Great introduction to the physics of counterbalancing. https://www.youtube.com/watch?v=OdmpYBSMWzM

>>35498 That certainly is a neat way to get your own motors. Definitely turn that speed down into torque tho. Then you just need to steal a control board off an ASMB-04b and you could control it just like a servo (not sure how much voltage it needs but the ASMB-04b does up to 24V). You can see the control board has separate connectors for the motor, motor power, and signal/board power. But being 3d printed it is probably going to be quite noisy. I might try building one eventually, but I'm focusing on just getting SPUD built fast n cheap as possible (without going mad, of course), and I think I'm doing pretty well at minimizing the uglification :) >>35454 Okay, now the concept is clear. Sorry about that :) Inmoov actually uses something kinda similar for the neck -which I modified for SPUD at one point, see vid.

>>35504 >This type of honest & healthy debate can only lead to a better outcome in the end for everyone involved here. Indeed! >>35549 >Do you mean just using this motor? Or, do you have your own design? I've designed my own. Though his is pretty good. I have designed three different sized axial motors (shoulder/hip/waist motor, knee/elbow motor, wrist/ankle motor), and two 'micro-ish' radial motors for neck and spine. The two radials are being redesigned as space is a premium and i can layout/fit some stuff better if they were larger diameter with thinner thickness and axial is well suited. I provided a link to that tutorial because it's well done. Largely my argument for using axial is because they can be easily diy'd at home since you can build them as air core, you can wind coils yourself easily with spools, you don't need costly arc magnets and you can pick and chose the kind of magnet you want, circular or bar. The axial flux efficiency/torque is largely just a bonus. The weight savings with axial is not insignificant either. >A cylinder is more mechanically resistant to that uneven loading causing problems. Axial flux rotors are flat disks, they form waves more easily, meaning the material must have far greater rigidity to reach the same power output safely. It largely depends on the construction, materials obviously, but the number of bearings and their placement, the coil/pole numbers, and your capabilities on making the airgap as small as possible. It's possible to remove a large amount of uneven loading from axial, it just requires some forethought. Like i said it's also better to get the parts machined out of some metal and use the 3dprints as a prototype. You can also stack coils and linked-stators in rotationally offset layers to further reduce uneven coil loading. I helped design a stacked and rotated layered axial pcb motor for school which uses large number of layers and it has low uneven loading and it has no bearings at all, just nylon spacers. There's a published paper on it, im sure you all can find it easily, I don't want to link it because I'd be doxing myself. >honestly wish that they were easier to mass produce so they would be easier to get at smaller scales. Personally after creating two different sized 'micro-ish' radials, using http://jystator.com/ I'd just stick with nema size motors if you can fit/afford them. It would be great if it radial were constructible at home, but it's not really feasible for most if anyone. Nema 8/11/17 are quite small and they can be gotten from China extremely cheaply for what they are. Sadly radial motors are quite heavy, for the same output you can see a 2 to 4 times weight reduction with axial, and you can use the weight savings for a better construction or live with uneven loading. The weight savings are extremely beneficial. Lower weight means less rotational mass in limbs and lower weight overall meaning smaller battery capacity can be used or exploit the savings for longer battery life. There is a reason most commercial humanoid robots today are using axial. >>35552 >Definitely turn that speed down into torque tho. Yeah toothed belt gearing on axial is the best way imo. my axials have the toothed belt gearing directly embedded on the outside of the rotor and the housing has spots for belt gears for torque stacking. >Then you just need to steal a control board off an ASMB-04b and you could control it just like a servo Interesting, that's a good idea. Does it support 3 phase? All my axial motors are 3 phase y configuration. i like doing the electronics from scratch as I can select components that will match the motor, I can select higher quality chips/components with the savings from diy-ing the motor, and I can move the high heat components to specific places for better cooling. plus a motor controller is pretty easy to make with a pico/pico2 with pio and the extra components i noted before. But i know not everyone wants to make everything from scratch. Personally everything from scratch is the fun part for me.

>>35551 THANKS! Achieving reasonably-pleasing humanoid gaits (with our feasible, available, hips/spine design choices available rn) will certainly need a number of these counterbalance design approaches (notably, for the central battery-mass located proximal to the robowaifu's pelvis/belly center-mass volume) to enable the nice, arc-based motions+balances needed. Great find, Kiwi. Cheers. :^) >=== -minor edit

>>35573 Walking gets exponentially harder when the robot gets bigger, because of things like the square-cube law. It's easy for the Femsapien (the toy robot on OP's post), but for any human sized robot, it's going to be difficult. Note that I'm not saying impossible.

>>35570 >Does it support 3 phase? I thought there was something wonky with that DIY motor, unfortunately the board only supports bog standard DC motors. I'm not sure about the official terminology (I am orkpilled after all) but it seems bog standard dc motors are technically 3 phase motors, they got a funny little dingus called a "communicator" which takes the standard dc electricity via brushes that bush against multiple metal contacts along the shaft so it mechanically handles sending current to coils 120 degrees out of synch as opposed to using an external controller. Or something like that. Me ork. Gib motah elecktrisity it zoggin' zoomz. Simpul az. Amusingly, brushes are typically the first things to go on motors /generators, the most notable I've experienced being a car's alternator (at approx 120-140k miles). Replacing them aka "rebuilding" an alternator can cost between $5-$35 (turns out a pontiac 6 shares the same alternator brushes as certain models of Hummer!), as opposed to buying a new one at $100+. A little DIY can save you lots of money and eliminating brushes can prolong the life of your robot.

>>35570 >Axial flux actually makes sense from a DIY perspective I’m in manufacturing, so my biased understanding can obscure some potentiality. I’ll take your word for it that axial flux is generally a superior design for mostly 3D printed motors. I’d like to know more. Read a few papers but, overall I still feel as if a definitive design that is easily reproducible remains elusive. Partially because coil winding requires special jigs to maintain proper tension and alignment. I’d like for you to create a dedicated thread on home fabrication of axial flux motors. You seem uniquely qualified for such a task and I’d like to work with you on the subject in a thread where it’ll be easy for others to find and follow along. >Nylon spacers as bearings You could also use glass or ceramic spheres/beads to make thrust bearings. Works great with PETG. I’d run a track near the center and near the outer extremes of the coils. 3D printing small indents to place them in would be easy and provide great support. Perhaps the nylon spacers are better, I’d say both methods are worth comparison. >Shoulder and hip motors You speak as if these are direct drive implementations. Care to elaborate their dimensions/volume, mass, torque speed curves, and cost/estimated time to fabricate? Deeply curious about the potential. >>35573 >Humanoid gates Walking like a person is sadly far away still. Still, Good to have eyes on the prize. >>35576 >Easy for Femisapien to walk That same walking gate can easily be scaled up well beyond human sizes. It’s just a simple mass shifting statically stable design. She moves some mass to adjust center of gravity from her midpoint to being over a foot. The design has some aspect that allows the rest of her to tilt, this can be done with slight slants or springs in her feet, springs or loose joints in her hips, or a more complex internal mechanism, which causes her other foot to be off the ground, enabling a step. Femisapien uses springs in her feet and hips, so when she twists her trunk with her arms splaying in and out to adjust her center of gravity, her legs naturally tilt due to gravity, with one foot hovering a few mm off the ground. Her thighs then move her lower legs back and forth, causing her to step. What makes Femisapien especially clever is that she distributes her mass via twisting her trunk and arms which puts less load on her motor relative to leaning. When scaled up to human scale, I’d recommend having an eccentric mass, (perhaps her breasts?) to cause her to move her center of gravity. This would reduce how much mass the arms would need to move. Though, the issue would then be giving her gigantic feet to maintain stability. Something like Nana in picrel. I’m a tad obsessed with mass shifting mechanisms, gravity is the most reliable power source. The most reliable actuator is the one that’s not there. No one has ever had a problem with Femisapiens hip and ankle tilt actuators.

>>35584 >Though, the issue would then be giving her gigantic feet to maintain stability. Something like Nana in picrel. That's where the square-cube law will strike HARD. Imagine walking in lead-filled snowshoes.

This thread is really paying off for it's general conceptual approach rn. >>35549 >honestly wish that they were easier to mass produce so they would be easier to get at smaller scales. This. >>35552 Good luck with your neck actuation assembly, Mechnomancer. It's looking good so far. >but I'm focusing on just getting SPUD built fast n cheap as possible (without going mad, of course) Lol. >and I think I'm doing pretty well at minimizing the uglification :) She's charming! One day you'll look back and enjoy the 'family album/growth chart' of dear SPUD and see just how far you've actually come with her, Anon! Keep moving forward. >>35570 >The two radials are being redesigned as space is a premium and i can layout/fit some stuff better if they were larger diameter with thinner thickness and axial is well suited. Exactly so, and this set of priorities is in play for several actuation sites around the robowaifu. Her hips, for example. >The weight savings with axial is not insignificant either. Low mass is arguably our single-most important design philosophy bullet point at this phase of our history (cf. >>4313, et al). Thanks for all the great information in your post, Anon. >>35576 >Walking gets exponentially harder when the robot gets bigger, because of things like the square-cube law. The basic reason we need to focus on the square-cube law is generally because of the (usually) concommitant increase in mass, as the volume cubes (see link above why this is a critical issue rn). If we use every trick in the book to keep our robowaifu's mass down, then it's simply a matter of the increased mechanical forces required for the longer limb 'levers'. A more-delicate balancing act, if you will. :^) >>35583 >(I am orkpilled after all) Lolwut? :D >>35584 >I’d like for you to create a dedicated thread on home fabrication of axial flux motors. You seem uniquely qualified for such a task and I’d like to work with you on the subject in a thread where it’ll be easy for others to find and follow along. This. All in favor of this idea, personally. >Still, Good to have eyes on the prize. Yup. IIRC, you yourself were the one who posted images here on the board of the prototype that had a mass located inside the torso volume that swung back and forth to provide the needed counterbalancing? My position is simply that we design a suitable system to use the high-mass batteries to swing back and forth instead of deadweight. Make sense? >What makes Femisapien especially clever is that she distributes her mass via twisting her trunk and arms which puts less load on her motor relative to leaning. Her designer is quite brilliant, IMO. >The most reliable actuator is the one that’s not there. This. The same is quite true of software as well, btw. :^) >>35590 >That's where the square-cube law will strike HARD. Imagine walking in lead-filled snowshoes. I think there's some subtleties there, GreerTech. The Square-Cube Law [1][2][3] is formulated regarding volume. For meatspace things like elephants, blue whales, and birbs, this roughly-translates directly into increased mass -- which is our general nemesis. But notice the last example, birbs. God designed them with a very low mass bone structure, and same for their primary lifting mechanism: feathers. As long as special tricks are used to keep the strength up and mass low (as with birbs), then the square-cube isn't quite the problem it would be otherwise. In Kiwi's example case, I'd suggest the concept is kind of like this instead: imagine you're walking on a pair of stilts, with 2'/60cm wide hoops affixed to the bottoms. While the results may be somewhat awkward (perhaps even comical), they wouldn't really require a significant increase in force required, but rather in the finesse involved. With the vase-printing approach (particularly if the 'mesh shell' paradigm [4] is used), her extra wide 'calves/feet' shouldn't really represent a significant increase in mass. Make sense? --- 1. https://worldbuilding.stackexchange.com/questions/215851/consequences-of-an-altered-square-cube-law 2. https://en.wikipedia.org/wiki/Square%E2%80%93cube_law 3. https://www.wolframalpha.com/input?i=cube+calculator 4. (cf. >>16170, >>16171, >>16525, et al) >=== -minor edit -add 'vase-printing' cmnt -add 'mesh shell' cmnt/crosslinks

>>35584 I kinda tried similar to the femisapien walking mechanism least year, not easy as it looks (especially when manually controlling the servos and some of them are the wrong way around!). That's why I'm gonna beef up a smol robodog with some ASMC-04bs and try to mount SPUD on the front of that. ASMC-04bs are pretty good in they have considerable torque (180kg/cm) and they control just like a servo except for an extra set of terminals for actual motor power. >>35604 >Good luck with your neck actuation assembly, Mechnomancer. It's looking good so far. Oh that is from like 6 month ago and I don't advise using that mechanism. The screw-drive takes too much current.

>>35590 >Square cube law More like square cube "guideline." That "law" assumes the part is 100% solid and scaled with complete uniformity. Reality can be whatever you want it to be, I can make the same part scale linearly with respect to volume and mass. Just need to get creative. In our case, we actually need to get creative because we are focusing on a large volume, low mass machine. >>35604 >Shifting internal mass That takes me back. Posted about that in 2017, the year I first got into this endeavor. Back then I was considering a wheel with bolts that'd work similar to old gyro trains. I'd say having a battery pack where the heart is, eccentrically connected to a shaft would be a far more clever, efficient, and practical. I have an itch to test this now. Got the ol' noggin' joggin'. >Femisapiens walking scales in processing "finesse" more than power/force required. Eloquently put, couldn't of elaborated better myself. >>35618 >Ork Femisapien legs You'd need an Ork psychic gestalt field for that to work. To put it seriously, your ankles and hip tilt shouldn't be powered. Your PVC has far too much play, cancelling out any potential height differential the legs could have. Most importantly, you're missing her entire body. The one part that is supposed to impart a height differential via manipulating her center of gravity. Your swing servos and parallel mechanism are correct. Your feet are also well thought out in terms of size and placement. It's a clever design, just needs a body, move her servos around, and find a way to reduce the play in her legs. Currently your design is similar to TecFoot from David Buckley. You may enjoy his work. http://davidbuckley.net/DB/A_Minimalist_Approach_to_Biped_Walking.htm

>>35604 >>35644 I see. Ironic that I failed to account for hollow designs, considering my design is mostly hollow. Most of my theorizing was based on the RoboSapien toy I had, there the walking and balancing was achieved by having giant feet with the relatively heavy batteries in the feet, hence the "lead-filled snowshoes", plus my own experimentation with building tall robots.

>>35618 Reminds me of the first Honda robot prototypes

>>35644 >You'd need an Ork psychic gestalt field for that to work. You also didn't notice the ankles were tilting the opposite way they should be :D I was only using 3 servo channels to control 6 of 'em. Frankly I'm amazed it even woobled. Springs might work well for shifting the mass of a smol robot, but a large robot's walk cycle could be easily upset if it was carrying a load or accidentally bumped which is why I tried powered. But once again why reinvent the wheel when you can yoink from other products lol

Here's some videos of the Femsapien and Robosapien walking https://youtu.be/IfyB558ItD8?si=0idXfxuLnUVGrjsu https://www.youtube.com/watch?v=4N0pERu9gQ4

>>35644 >gyro trains Lol, that's very cool-looking Anon! :D >I have an itch to test this now. Got the ol' noggin' joggin'. Please do! I think a single actuator that drives a pushrod in either direction should probably suffice. It's what I'll plan the control interface for. Cheers, Kiwi. Maidcom Mini's coming right along! :^)

>>35647 We're all learning, I've made far worse assumptions. Wish I had someone to correct me in the early days. >>35654 >Powering extra DOF for safety Sensible, I can understand how that makes sense to ensure she doesn't topple over when dealing with large inertial disturbances. Circumferential Flux Motors A new kind of motor that is essentially a rotary solenoid. Coils produce a flux field that imparts kinetic motion within a magnet, see gif for gist. This would potentially allow for a motor that has nearly perfect efficiency with the dirt simple control of brushed DC motors. The only site I found with information on them; https://www.motion-robotics.co.uk/cf-motor How do they interface with magnets inside the coils? Their coils are wound as a C-shape. I'd make one by having magnets with teeth which snap together to form an annulus/ring gear for a planetary gear train. Sets of coils would be wrapped around the annulus with space for planet gear meshing. The planets are held in place on the carrier to prevent clashing with. the coils. (Carrier not in picrel because it looked weird.) Sun gear providing the final output for the system. I put a hex connector because I like them. How would you design or implement a circumferential flux motor?

>>35662 >gif related Wow that's wild. What's the little 'tube car', some kind of battery or other? >How would you design or implement a circumferential flux motor? Could we co-locate 3 of these together into a tight volume to create a universal direction ball-actuator in the hip joints, ala Sukabu's designs, et al : (cf. >>35663, etc.)?

>>35664 It's an AA battery with neodymium magnets at the front and back. Those magnets function as both brushes to induce and electromagnetic field in the copper coil, and they act as the motive element by "pushing" against that induced field. An ingenious machine, essentially a flexible solenoid with power held within the armature. >Using three for her hip I very much intend to make that happen! Though I want to make it by end of year, it'll likely take at least 2 considering MaidCom 1 is primary focus.

>>35662 That was something I saw long time ago, but I overlooked that the "train" was a battery, and I thought I could use it to pull "muscle" strings to move robot parts. But it turned out that it was too weak: >>4429

>>35673 Just need to calculate based on your needs for your solenoid. https://calculatorultra.com/en/tool/solenoid-force-calculator.html#gsc.tab=0

>>35498 Great comment. I've thought about Halbach arrays but didn't think about them in a coreless usage. The paper got me to thinking.

Responding to >>36430 from the diy motor thread. >Maybe we should consider a more unconventional design thats more similar to how muscles work I just want to say upfront that I’m not trying to be critical of your idea, I really appreciate outside the box thinking, since it’s exactly what we need to push robowaifu development forward. On the topic of your design, If the magnet is fixed and the coil moves, the coil will experience a force, but it may not move efficiently because electromagnetic forces generally require a closed magnetic circuit for strong actuation. In your design, the permanent magnet at the bottom has a magnetic field extending outward. The coil generates its own magnetic field when current flows through it. However, the fields don’t have a clear return path, meaning most of the flux will escape into free space rather than interacting efficiently. The force might not be strong enough to move the coil significantly unless very high currents are used. The spring’s placement directly below the coil could also interfere with the electromagnetic forces. Solenoid-based actuators are notoriously difficult for precise movement due to their binary nature (typically fully on or off), high hysteresis, and nonlinear force response. But based on your drawing it's far more like a Linear Voice Coil Motor except your coil doesn't surround the return spring. Look into Linear Voice Coil Motor or Voice Coil Actuators. Typically these have no torque rating and instead have a linear force rating. VCA/LCVM generally produce a low linear force, but they excel in applications requiring high precision, fast response times. They are largely unsuitable for applications requiring high rotational torque. (I assume you're wanting to drive a linkage to rotate limbs via the linear force). The rest of my post will be about magnetic linear actuators and more specifically linear synchronous motors (LSAs). These LSAs are largely how maglev trains and modern roller coasters work. These systems rely on electromagnetic forces to generate linear motion directly, eliminating the need for mechanical conversion from rotary motion. Industrial automation often uses them for contactless linear transport. These are really unlike any other commonly used actuator, such as a ball screw, timing belt, or rack and pinion, they provide high precision, high velocity, high force and long travel. They are pretty complicated and extraordinary expensive devices. These systems are extremely useful in automation, but largely no one ever thinks of them or even knows about them outside of maglev trains. See https://www.youtube.com/watch?v=ICN2iO3nbiQ for the pic in action and see https://www.instructables.com/DIY-IRONLESS-LINEAR-SERVO-MOTOR/ for more information on the pic. Looks amazing right? While LSAs excel in high-speed automation (maglev trains, CNC automation), they face significant challenges in humanoid robotics due to power inefficiency, control complexity, and limited precision for small-range movements. Below is my experience with them. Using LSAs as linear actuators is a really intriguing idea, I played around with the idea many years ago as linear actuators in a CNC shop before there was really any large interest in humanoid robotics. I've been trying to build a good humanoid robot for many years (since the 90's) and the problem has always been good ways to translate motion with low power. At the shop I was tasked with building some automation and they had a few LSAs lying around unused and I thought they were pretty cool and thought they could be used as linear actuators, so I messed around with them on my lunches. I built a LSA bicep/forearm and wrote some pages of notes on my experiences with them. (I wish I had some pictures but this was before there were cameras on phones, lol.) Here's some of my observed limitations with using LSAs as linear actuators. The main problem with them for humanoid robotics is multi-faceted. LSAs require significant magnetic field strength and large electromagnets or permanent magnet arrays to function efficiently, making them bulky compared to other options. The amount of current required for high-torque, low-speed operation (needed for humanoid joints) is substantial, leading to high power consumption. The coils in the actuator generate heat due to resistive losses, requiring cooling systems, which further increases size and complexity. LSAs are often water-cooled in automation systems, at least the ones I used were. Unlike geared motors, an LSA requires continuous power to hold a position. If power is lost, the joint loses all resistance, making it impractical for static postures without a mechanical brake. Furthermore, Since LSAs operate on an electromagnetic field, they constantly draw power to maintain a position, unlike other kinds of motors which can maintain positions with mechanical resistance due to gearing. LSAs are great at high-speed travel over long distances, like maglev systems. But humanoid robots require fine, precise movements in small ranges (gripping, balancing, small joint corrections). Magnetic force distribution in LSAs doesn't favor short-range precision, making them inefficient for fine motor control. LSAs require precise real-time control of magnetic fields to achieve stable, smooth motion. Unlike traditional servos (which only need PID control), LSAs need a dynamic magnetic field generation system, leading to increased CPU load and additional sensor requirements. Limited Back-Drivability: Unlike geared motors, LSAs resist passive motion, which can make them problematic for compliance-based movements in humanoid robots (soft grasping, adapting to external forces). The lack of small precise movements, limited back-drivability, and high power requirements is a real killer here. Also unlike rotational motor-based humanoid robots (where actuators are largely modular), LSAs require custom electromagnetic configurations per joint, making them hard to scale for general use.

>>36432 POTD I truly appreciate the scientific basis around your engineering thinking process, Axial. Thanks for elevating the general discussion here on the board. Cheers.

>>36432 Great comment . I've been thinking about much the same sort of thing but weird tangents. Most automobiles are moving towards switched reluctance motors. Which, I believe, is sort of what you have pictured but linear. What I have been thinking of is a mash up of a linear and regular circular reluctance motor. Looking at the linear you showed some of the problems are, your moving the coils (heavy, needs wiring that flexes and takes space) and the actual coil (working) area is a very small portion of the track. As you mentioned this means high currents to pack all the forces you need into that small coil area. What if you turned the thing sort of inside out. What if instead you moved the track? But in this case the track turns in a circle. Much like a fan belt runs between two pulleys. So the coils are stationary and the inductive part is on the belt which can rotate linearly til it runs around the pulley and then comes back. It's a belt. You could put coils on both sides driving a very large linear area. This defeats some of the problems in the rotary inductive reactance motor. High heat build up because it's all enclosed in the cylinder motor with limited area for coils. With it spread out you don't have either problem, Another feature is you can make the belt, chain, moving part as long as you want with a large coil area over many links. This means the large majority of the whole of the motor is being driven. Not just some small section. For movement you could tie a line directly to the chain/belt/ driven part or you could wrap a line that is pulled around one of the axles giving you a step down transmission. I think a holding force, without power, is unnecessary as people don't have that so it's not needed in a waifu. In reference to Halbach arrays >>35695 You mentioned the return path for the magnetic field. I wonder what would that be for Halbach arrays? Could you put metal return paths on the sides and have that work?

>>36439 of course! >>36523 Hmm your idea is intriguing, I'll have to stew on that for a bit. The main thing I would be worried about would be complexity and the custom reluctance control algorithm. Interesting thought though! >switched reluctance motors These are very cool but very tricky to get right. In the future once I get the Coreless Axial Flux Motor stuff finished, I would like to check these out more as they are significantly cheaper to produce because there are no permanent magnets needed! Unlike permanent magnet motors, it relies solely on the interaction between the stator's electromagnets and the salient poles of the rotor. In general, with SRM you have more stator poles and fewer rotor poles, for example a 6/4 SRM has 6 stator poles and 4 rotor poles. When a stator coil is energized, it creates a strong magnetic field. The rotor aligns itself to minimize the magnetic reluctance (resistance to magnetic flux). This movement generates torque as the rotor seeks the lowest reluctance path. Once the rotor aligns with the first energized stator pole, that coil is turned off, and the next phase is activated. This switching sequence ensures continuous rotation. The rotor has no magnets, making SRMs highly robust, cheaper, and suitable for high-temperature environments. The main problem with these kinds of motors is the optimal drive waveform is not a pure sinusoid, making it harder to create electronics and program the driver. This is due to the non linear torque relative to rotor displacement and the windings highly position dependent inductance. The other problem is high torque ripple. Torque ripple is basically the periodic increase or decrease in output torque as the motor shaft rotates. Cogging torque is kind of a good example of torque ripple, if you ever rotated a stepper motor on a 3d printer and you feel the rotational detents, that's cogging torque. Technically speaking, cogging torque and torque ripple are different, but they both cause uneven motion in electric motors, as they come from different sources, the mental idea and picture is the same though. Cogging torque is a magnetic locking effect whereas torque ripple is a fluctuating output torque. When the electronics for an SRM are switching it must deliver power to the different windings and limit torque ripple, this is what causes the high complexity in electronic/programming design. (one of two)

>>36523 >You mentioned the return path for the magnetic field. I wonder what would that be for Halbach arrays? Could you put metal return paths on the sides and have that work? You can! I'll try and explain Halbach arrays and return paths for fields a bit further (this might be a better post for the DIY motor thread, but we can link it) So the interesting thing about Halbach arrays is the magnetic field is concentrated on one side while nearly canceling out on the opposite side. The Halbach Array works due to a carefully arranged sequence of magnetization directions that reinforce the magnetic field on one side while nearly canceling it on the opposite side. This is achieved through vector addition of magnetic fields, which results in constructive interference on one side and destructive interference on the other. If i remember correctly this is called the magnetic field superposition. Knowing this, we can tackle the return path problem in multiple ways. >Free Space Halbach In a typical linear or cylindrical Halbach array, the return flux is distributed in space around the array. This is common in applications where weight reduction is prioritized, such as maglev trains and brushless motors with air-core stators. One main problem with a Free Space Halbach is the lower efficiency due to leakage flux and weaker field strength on the active side. This is your general Halbach Array with no return path consideration, and is probably the most common. >Ferromagnetic Backing Plate (Steel or Soft Iron) If we place a high-permeability material (like steel or soft iron) on the "weak side" of the Halbach array, it provides a low-reluctance return path. This is generally used in rotor designs in axial flux motors and linear Halbach tracks. What this backing plate does is it increases field strength on the active side by directing more flux towards it. The main problem with backing plates is added weight and potential eddy current losses. >Yoke Based Return Path In cylindrical Halbach rotors (like a motor), a ferromagnetic yoke can be placed around the outer perimeter and can be used as a return path. This yoke guides the flux back to the magnets, increasing efficiency. Some axial flux motors place a steel backplate behind the magnets on each rotor. >Opposing Halbach Arrays (Self-Contained Return Path) Using two opposing Halbach arrays creates a closed-loop magnetic path. This is commonly used in linear Halbach motors and magnetic bearings. You can also have multiple Halbach Arrays in a radial flux motor where one array is within the coil and the other one surrounds the coil. The secondary Halbach array reduces flux leakage and increases field uniformity. The only downside is a more complex assembly and alignment. >Flux Return with Soft Magnetic Composites (SMCs) Instead of solid steel or soft iron, soft magnetic composites (SMCs) can be used to shape and direct the flux with reduced eddy currents. Useful in high frequency applications where laminated steel or soft iron would cause excessive losses. This is pretty advanced and costly, but you can diy fairly cheaply with iron powder and epoxy. Downside is the added weight and reduced eddy currents. >Non-Magnetic Spacers Interestingly using air gaps and non-magnetic spacers you can adjust field strength and direct return paths. It allows fine tuning without adding significant weight or increasing losses. >Hybrid Halbach and Conventional Designs This is also called a "Partial Halbach Array" where you have additional traditional magnet arrangements to provide a better return path. Some radial flux motors use a Halbach configuration on one side and traditional radial magnets on the other. I've actually never seen this configuration in use but one of the books I have talks about it, so I figured I'd mention it. The main problem with magnetics in general is the math is pretty heavy and the fields are invisible. What's worse is magnetic simulation software is extremely expensive, but some software people use have simpler models which are pretty useful (like freecad). You can drastically change field strength and return paths by subtle changes of magnet placement and air gaps alone.

>>36607 >>Non-Magnetic Spacers Interestingly using air gaps and non-magnetic spacers you can adjust field strength and direct return paths. It allows fine tuning without adding significant weight or increasing losses. I've been reading quite a bit about ferrites and soft magnetic materials as I'm interested in motors and magnetic amplifiers. I'm really sure I get the "air gap" thing. My reading, and likely I have this wrong, the air gaps help keep you from going into saturation in the field focusing material or maybe better termed as where the magnetic field can more easily go through. You said that the powdered materiel is more costly. I think for our needs that would be somewhat incorrect "if" you consider the processing of the material and not just raw, per pound cost. It's my understanding that the powdered material, or some of it, has the advantage of the powder being separated by air or glue of some sort gives it the advantages of air gaps built in. It's also my understanding that the air gaps have the ability of raising the inductance of your magnetic material temporarily lowering it's permeability (meaning it's ability to channel magnetic fields). With higher inductance it lowers the inrush of current. Or this is what I assume the purpose is. I;m not 100% sure of this but keep looking. It;s remarkably hard to find scientific information that gives you a broad overall view. They all cover you up with equations and graphs without much telling you the over all purpose. Could it be?? that using the air gaps you can have a large core with higher current wiring BUT by raising the inductance and lowering inrush current you can still get a large magnetic field while not melting down your coil or turning your actuator into a oven??? As I say I'm not exactly 100% sure what air gaps really do. I think I sort of do but I wonder is there not some more satisfactory method of doing this without essentially choking the field down? Like why not use a material with less permeability in the first place??? A weird factoid. The air gaps in the transformers in guitar amplifiers I read are what gives them their great sounding even harmonic distortion sound. Apparently they saturate and clip the output, but in a way that sounds full tilt rock and roll. https://en.wikipedia.org/wiki/Sendust I've been trying to buy some sendust magnetic material. https://en.wikipedia.org/wiki/Sendust I found good deals in China but the shipping is a killer. I may do it anyways. US suppliers are mostly interested in selling not the powder but the whole core already made. I have no interest in that. And US supplies always want you to write in, get quotes, blah, blah, its difficult to find a straight, buy this many kilos for this many dollars. Deepseek AI says that higher permeability cores can be controlled with smaller DC control currents in magnetic amplifiers. This seems contradictory to me but that's what it said. I will have to ask grok what it thinks. If I could understand the air gap thing it could save me from needing higher permeability (more expensive) cores.

>>36663 >still get a large magnetic field while not melting down your coil or turning your actuator into a oven??? When I say this maybe I should clarify so people know what I'm talking about. I know a decent amount about AC electric motors. In many of them they have a separate circuit or some sort of arrangement to limit the current when they start. Some have big resistors or external cast iron resistors in really big motors. Some have relays that run the coils in series until the motor gets up to speed then switches them to parallel. All sorts. I'm thinking that these air gaps do much the same. The total magnetic field is based on the current but starting inrushes of current can be really high. The idea of the air gap is to slow down the inrush or so I surmise, but of course I'm not really sure.

>>36663 >the air gaps help keep you from going into saturation in the field focusing material or maybe better termed as where the magnetic field can more easily go through. Yes, exactly! The air gap helps prevent saturation in the field focusing material (like iron or ferrite) by acting as a flux bottleneck, ensuring that the magnetic field does not become too concentrated in one area. A high-permeability material (like laminated iron or ferrite) naturally 'funnels' magnetic flux efficiently, but it has a limit. Once it reaches magnetic saturation, adding more current does not increase the magnetic field proportionally, this leads to inefficiencies and heat buildup. If you add an air gap, you can increase the total reluctance (resistance to magnetic flux), which spreads the field more evenly. You can lower the effective permeability of the core, meaning it takes more current before reaching saturation. and the magnetic energy is partially stored in the air gap itself, reducing localized core saturation. The best way to think of an air gap is it acts like a pressure relief valve for the magnetic field, preventing the material from becoming overwhelmed and ensuring a more controlled magnetic response. To recap, without an air gap, a high permeability core saturates quickly, and any extra current turns into wasted heat instead of increasing the field. By adding an air gap, the field is distributed more evenly, preventing localized hot spots and allowing you to push more current through the coil without immediate saturation. This reduces hysteresis losses and eddy currents, both of which contribute to heating. >You said that the powdered materiel is more costly. I think for our needs that would be somewhat incorrect "if" you consider the processing of the material and not just raw, per pound cost. I said that SMCs are expensive, and that you can diy them yourself cheaply with iron powder and epoxy. Well designed SMCs are ridiculously expensive. >It's my understanding that the powdered material, or some of it, has the advantage of the powder being separated by air or glue of some sort gives it the advantages of air gaps built in. Kind of, it all depends on the material properties of the binder (glue/epoxy/etc) and interaction with the iron powder itself. It can act like an airgap but really it's not an air gap at all but rather a nonmagnetic material so it will influence the system differently than just air. Plus some non-magnetic binder materials (glue/epoxy/etc) can interact with the iron powder causing funky unexpected results. There's a bunch of papers on this. I remember one paper where a non-magnetic binder material turned slightly magnetic in the presence of iron. If I remember correctly, there was a chemical reaction and caused the binder to turn slightly magnetic itself. The electrical and chemical properties of the binder are probably the most significant part in the equation, since iron powder itself is largely a constant. Also there is paramagnetism in materials, a kind of magnetism which only occurs in the presence of an externally applied magnetic field. Material science is a very complex subject that I don't know that much about tbh. >It's also my understanding that the air gaps have the ability of raising the inductance of your magnetic material temporarily lowering it's permeability (meaning it's ability to channel magnetic fields). With higher inductance it lowers the inrush of current. Or this is what I assume the purpose is. I;m not 100% sure of this but keep looking. Yeah you're on the right track! It seems like you already got the tricky part down. The tricky part is that an air gap reduces overall permeability, which you might assume would reduce inductance. However, because the gap stores more magnetic energy, in many practical applications, the inductance ends up increasing or stabilizing instead of dropping. When you power on a motor or transformer, an air gapped core slows down the rate at which current can rise, reducing inrush current. This prevents excessive current spikes that could damage components or cause overheating. (1of2)

>>36663 >Could it be?? that using the air gaps you can have a large core with higher current wiring BUT by raising the inductance and lowering inrush current you can still get a large magnetic field while not melting down your coil or turning your actuator into a oven??? You are absolutely correct in thinking that air gaps allow you to use a large core with higher current wiring while managing inductance and preventing excessive heating. The key here is that an air gap regulates flux density, allowing you to generate strong magnetic fields without saturating the core and overheating the coil. >As I say I'm not exactly 100% sure what air gaps really do. I think I sort of do but I wonder is there not some more satisfactory method of doing this without essentially choking the field down? Like why not use a material with less permeability in the first place??? The reason is that low-permeability materials do not concentrate flux well. You need much more current to generate the same field strength, leading to higher electrical losses. Magnetic circuits become inefficient because the flux spreads out rather than staying focused where you need it. Energy storage is less effective, which can cause performance problems in motors, transformers, and inductors. By contrast, a high-permeability material with an air gap gives you the best of both worlds. The core still focuses most of the flux, but the air gap acts as a buffer, preventing saturation and excessive heating. You get better energy storage and less wasted power than if you just used a low-permeability material. Air gaps let you fine-tune performance without completely "choking" the field, making them the best practical option. >It;s remarkably hard to find scientific information that gives you a broad overall view. They all cover you up with equations and graphs without much telling you the over all purpose. Good books help but largely have the same problem. >Sendust Way to expensive for DIY. Iron powder is the most cost effective of all the powder cores. Don't bother with trying to source sendust. If you really wanted sendust, it's composition is typically 85% iron, 9% silicon and 6% aluminum. You can always mix your own batch up. I've seen this done before, though personally I wouldn't do it, I prefer coreless designs. >US suppliers are mostly interested in selling not the powder but the whole core already made. Well yeah, that's how they make money. They generally are selling a service and not really selling the end product. You're paying for their service to do a whole lot more than just make a core. They do all sorts of things to optimize your core design and provide you with a end product. >And US supplies always want you to write in, get quotes, blah, blah, its difficult to find a straight, buy this many kilos for this many dollars. Yep, the old "if you have to ask the price, you can't afford it". >If I could understand the air gap thing it could save me from needing higher permeability (more expensive) cores. Coreless motors are far better for robowaifu, imo. (2of2)

>>36673 >Good books help but largely have the same problem. The extraordinarily-eminent Carver Mead said that (my own very crude paraphrase here): >"Much of our difficulties in physics today comes from having to deal with Maxwell's equations, because they are all contrived around the idea of the Aether. You gotta get rid of that stuff! Then things get much simpler. :)" (cf. : >>33943, @ ~27mins ). I'm very interested to hear your take on that notion, Axial. >=== -fmt, minor edit

>>36672 In an earlier post I made a mistake an left out the I "DON'T" really understand air gaps. I'm getting much closer. >air gap ... acting as a flux bottleneck, ensuring that the magnetic field does not become too concentrated in one area. A high-permeability material (like laminated iron or ferrite) naturally 'funnels' magnetic flux efficiently, but it has a limit. Once it reaches magnetic saturation, adding more current does not increase the magnetic field proportionally, this leads to inefficiencies and heat buildup That I really get. Makes good sense. >To recap, without an air gap, a high permeability core saturates quickly, and any extra current turns into wasted heat instead of increasing the field. By adding an air gap, the field is distributed more evenly, preventing localized hot spots and allowing you to push more current through the coil without immediate saturation. This reduces hysteresis losses and eddy currents, both of which contribute to heating. I get this too. The problem I have is "IF" the air gap causes lower permeability then what's the point of high permeability material? Why not use something cheaper with less? Now "IF" what I said about electric motors here >>36665 and avoiding large inrushes of current BUT allowing large magnetic fields to go through with the higher permeability material, then I get that. I guess it depends on "IF" it's like AC motors. (An assumption)The killer is the "rapid change in current" not necessarily the current volume or amount. (Speculation)Rapid changes mean saturation but more gradual rises of current are less saturating. It's a bit confusing because according to Deepseek high permeability materials can be saturated with lower levels of DC current when used in magnetic amplifier. But it would seem that the low permeability would allow MORE magnetic field, meaning the level of DC bias would have to be higher before it choked. Some of the data I got from a paper referenced by Duckduckgo AI. This one below. I can not find a direct link. "A Comparison of Molybdenum Permalloy Powder and Sendust Cores for Energy Storage Inductors" Tim Slattery, Applications Engineer, The Arnold Engineering Company, Marengo, Illinois, USA May, 2000i "Molybdenum permalloy powder and sendust cores are described and compared." Now it says, "...cores in power conversion applications. Energy storage and release takes place in the gaps between magnetic metal powder particles. An insulation material that is applied to the powder before compaction maintains these gaps. Particle-to-particle insulation also reduces eddy currents in the core. The magnetizing force (magnetic field of the winding) works with the easily magnetized metal to achieve high magnetic flux density (induction) in free space within the core. The free space is divided into the many gaps that are uniformly distributed along the entire length of the magnetic path. This distributed gap is one of the most important aspects of powder cores. Fringing fields and associated winding eddy current losses caused by one or two discrete gaps in the core path length are avoided.." It seems almost as if the air gaps store more energy than the high perm material itself. Is it, as you said, the real reason this is, is because the air gaps make the magnetic field EVENLY"spread around the material? So that all of it is used. And is the energy stored in the coil alone or is some of it stored in the air or a combination of the two? The paper seems to posit that the field is stored in the "Air gaps" and the permeable materials is only to channel it and focus on these gaps. This of course brings up the question of why have the permeable material in the first place if the energy is stored in the air gaps?? It's all so confusing. My interest in this mostly lies in magnetic amplifiers but of course switch mode power supplies, inductive reactance motors and forces created. BTW I found Sendust powder suppliers in China that would sell sendust powder for $12 a Kg in 3Kg quantities but the shipping was like $90. One company told me they would send me 3Kg for free if I paid shipping. So $90 USD. I may end up doing that. Get a FedEx account, which seems to be what they want. But not until I understand the parameters I need. May be sendust is a waste of money for what I want.

Ok you answered stuff I didn't see before my last comment. Thanks a heap for the tutoring. It's VERY MUCH appreciated. And in turn I will tell you why I'm so interested in this. If you want to recreate all the muscles in a human then you need about 300 actuators. This means 300 MOSFETS or equivalent. They are cheap but good ones, not Chinese, will run you 50 cents to a dollar. Then of course you have driver circuits to drive the MOSFETS completely so you don't burn them up, more money, more complexity, then diodes and resistors to control the back EMF from the coils. It gets complicated fast. And pricey. You also have, with separate MODFETS like this, a mass of wires of fairly high size to go to each individual muscle. All of this of course requires boards, big flow soldier equipment to place it. It adds up real fast. So "what if" instead you use magnetic amplifiers made from powdered cores . Compare that to buying 3Kg of sendust for $12 a Kg, some silver(alloy) solder for maybe $30 a pound, a little epoxy and manufacturing this stuff in a oven. Mag amps are seriously robust. And the permeable material, if metal based, will allow very high short term amperages because they conduct heat really well. Mag amps is how V-2 rockets and WWII battleships were controlled and they hardly ever broke. Possibly you could integrate the amplifier as part of the actuator. I see no reason you couldn't. The power would be one long bus of AC power. The control wires for the various muscles would only need to be very small DC control level circuits. I have an idea for the coils in the permeable material. Make molds with hollows in them. The hollows would be the coils. Pack in epoxy and your permeable material. Now you have the core with a "nothing" area for the coils. Pack the coil area with very fine copper powder, and use a good silver alloy soldier that can be sucked up into the copper powder spaces along with the copper. Put in a oven, solder runs into copper powder and now you have a mass produced magnetic amplifier/actuator. All this greatly depends on 3D printers to make the molds. Another method is to print the actual coils in a resin 3D printer. The resin printers have outstanding resolution. Make a mold of the coil. Pour low temperature metal into the mold. Pack your permeable material around the metal coil then melt it out. You only need boiling water temp or less to do so. Then add copper powder, soldier. The key here once you set this up you can easily mass produce all these molds and rapidly squeegee in all the materials. The other alternative is hydraulics which might be ok if you made bladder type hydraulics but...I don't like hydraulics, but even if I don't like them it may be the cheapest, best solution.

>>36677 What I understand is that quote was in reference to special relativity and how light needed a medium to travel through in Maxwell's original equations. Originally Maxell's equations were formulated in the context of the luminiferous aether. An assumed medium through which light waves propagated, similar to how sound waves propagate through air. Once special relativity hit and showed that no such medium was necessary, Maxwell's equations were reinterpreted in a relativistic, aether free framework. The removal of aether made Maxwell's equations simpler, symmetric, and consistent with relativity. Instead of relying on a fictitious medium, modern physics understands electromagnetism as a manifestation of relativistic field theory, where the electric and magnetic fields transform into each other depending on the observer's motion. (First Picture) Interestingly if you look at Maxwell's equations through the lens of Geometric Algebra/Geometric Calculus and specifically in the SpaceTime Algebra (STA) formulation you can make it even simpler without tensors. This is the second picture. Instead of dealing with four separate equations (or the complicated tensor formulations in differential geometry), Maxwell's equations reduce to a single geometric equation. This approach unifies the equations into a single, compact form, showing that electromagnetism is inherently geometric. Which is pretty cool and intuitive! Though this requires esoteric GA/GC knowledge. Side note: Is it possible to include math like this picture on here in text instead of me using github with markdown and pictures?

>>36672 >When you power on a motor or transformer, an air gapped core slows down the rate at which current can rise, reducing inrush current. This prevents excessive current spikes that could damage components or cause overheating. Ok I got this now. Just like a motor when sitting still has a very low inductance, meaning the current flowing into it will melt it down, but after it gets going the inductance rises. This means all the power, like a pure load resister, will be dumped into the motor coils BUT with higher resistance, lowering the current so as to not cook the motor. A question. How does the air gap effect the attraction of high permeable materials to magnetic fields? Will it lower the force or only for a moment? Basically the the air gap acting as a dampener? I'm going to read over, and over, what you wrote, then formulate some really specific questions and hit Deepseek and grok up. I I bet I can really understand this. I'm one of those weird individuals that likes to understand the whole package instead of just cook booking things. "If" i can come to this understanding I think I could make something very cost effective.

>>36672 > I remember one paper where a non-magnetic binder material turned slightly magnetic in the presence of iron. My present plan is to use high temperature epoxy. I've read you can get it to 600F but I know of one product that gets to 450F but it's air, room temperature cured. Some of the very high temp stuff you have to bake cure it for many hours at high temperatures of 400F or more. Non starter as it will be a huge time killer. Maybe ok for fighter planes but it would slow down production. I want to note that I did some rough figures on efficiency of humans compared to Tesla's motor and we have a HUGE amount of room to work with. We can make something FAR, FAR less efficient and power to weight without much penalty or basically none at all. Tesla 3 motor output = 258KW(345HP) at 27.99Kg(60lbs.) but a human rarely puts out more than 400 watts in peak.(this is athlete level) https://en.wikipedia.org/wiki/Human_power So the Tesla motor puts out 4300 watts/pound and human puts out(at 250watts and 200lbs.), 1.25 watts/pound My goal is a robowaifu at least as strong as a very good athlete, so I get it to carry stuff. Very extreme peak performance in humans is 1,000 watts but only for a few seconds.

Axil I REALLY APPRECIATE all the tutoring you have done. It's super helpful. I think have a really good handle on things now. I now need some sendust alloy. There;'s a HUGE heap of materials but I settled, so far on sendust because it's not too expensive, has really good permeability and very low to no magnetostriction. Meaning it does not expand and contract in magnetic fields. Materials that do have a hum. Like the 60Hz hum you get from large iron transformers. Don't need a humming buzzing waifu. It also being metallic will conduct heat fairly well. My basic idea is a buss of AC at higher frequency, to be determined. For giggles, 50KHz with magnetic amplifiers driving actuators.

>>36677 >>36708 >Interestingly if you look at Maxwell's equations through the lens of Geometric Algebra/Geometric Calculus and specifically in the SpaceTime Algebra (STA) formulation you can make it even simpler without tensors. This is the second picture. Instead of dealing with four separate equations (or the complicated tensor formulations in differential geometry), Maxwell's equations reduce to a single geometric equation. This approach unifies the equations into a single, compact form, showing that electromagnetism is inherently geometric. Which is pretty cool and intuitive! Though this requires esoteric GA/GC knowledge. I should probably add some more context for digestion. When I said electromagnetism is inherently geometric, I mean that Maxwell's equations describe the structure of spacetime itself and that the electromagnetic field is a geometric object, not just a set of arbitrary vector equations. Traditionally, electromagnetism is described using electric (E) and magnetic (B) fields, which are treated as separate three-dimensional vector fields. However, in spacetime algebra (STA), these are naturally unified into a single object, a bivector F: F=E+IB. Where I=e1e2e3 is the pseudoscalar (volume element of space). E is a vector (directional quantity). B is a pseudovector (axial vector related to rotations). This means that electromagnetism is not just a set of field values floating in space; it's actually a structure embedded in spacetime itself. Furthermore, electromagnetic waves are really just geometric rotations in Spacetime. When an electromagnetic wave propagates, what is actually happening is a rotational oscillation of the electromagnetic field bivector F in spacetime. >In 3D, we think of electric and magnetic fields oscillating perpendicular to each other. >In 4D spacetime, this is better understood as a single rotating bivector, much like a complex number or spinor. This interpretation makes electromagnetism look structurally similar to spinor rotations in quantum mechanics, hinting at a deep connection between electromagnetism and fundamental spacetime geometry. Maxwell’s equations are really a single geometric constraint, instead of being four separate equations, Maxwell’s equations collapse into a single equation provided in the second image. This is structurally similar to the Clifford-Dirac equation for spinors in quantum mechanics. In other words, electromagnetism is not just a force; it is a geometric feature of spacetime itself. The Lorentz Force is a natural geometric action, instead of defining the Lorentz force as an arbitrary rule: F=q(E+v*B). Geometric Algebra shows that the force law is actually a consequence of spacetime structure: Fqv. where v is the four-velocity of a charged particle. This tells us that charged particles follow geodesic-like paths through spacetime, modified by the structure of the electromagnetic field. The unification with relativity, in standard vector calculus, we awkwardly separate E and B and then recombine them in relativity into the Faraday tensor F_muν (Faraday tensor F_muv represents the electromagnetic field in a relativistic framework, and it’s a rank-2 antisymmetric tensor, meaning it has two indices [mu and v]). But in Geometric Algebra, we never need to separate them to begin with! The bivector field F is already a naturally four-dimensional object. This means electromagnetism is not something separate from spacetime; it is a direct consequence of spacetime geometry. >Maybe this is all too esoteric, but hopefully it's somewhat informative or at least thought provoking. If anyone is interested further and wants to know more, https://bivector.net/ is the best place online about GA/GC, while Alan Macdonald has the best books to learn about GA/GC (Linear and Geometric Algebra, Vector and Geometric Calculus). Hopefully this has been somewhat mind-opening. I know when I learned that electromagnetism was a structure embedded in spacetime itself. It kind of blew my mind for awhile. >>36711 You're very welcome. You are definitely getting it, in no time you'll understand it as much as anyone else does. Would you like me to continue to going over your posts or are you good? I don't mind.

>>36712 Anything, anything, you wish to add would only add to my thrill and joy. >>36677 >>36708 >Geometric Algebra Yep yep. I've been babbling about Geometric algebra a good deal. Not that I can work with it competently but I recognize the significance and I have some rudimentary understanding of what it's good for...like everything in physics. Chobitsu you didn't ask me but I have something to add that is very pertinent. The experiment that all the textbooks say proves that there is no aether is NOT represented correctly THEY LIE. Directly and bold faced lie. Here's what the Duckduckgo AI says, "...Michelson-Morley experiment was designed to detect the presence of the luminiferous ether, a medium thought to carry light waves. However, the experiment found no difference in the speed of light in different directions..." This is not true. I have personally seen an actual 100% original issue of the report myself in the univ. library. It does not say zero. I read it myself. I was clued into this by G. Harry Stine. They DID NOT find zero difference as is always said. I can't remember the exact numbers but these are probably close. They were looking for the speed of the Earth in orbit like 25Km/s but they found something like 8/Km/s. The statement that they found zero is a lie. And furthermore other scientist have repeated the experiment hundreds of times with more accurate equipment and they, also, did not get zero.(These used to be listed in Wikipedia but they've obscured them) One scientist did hundreds and hundreds of test with all sorts of conditions. He made sheds to cover the light path, all sorts of stuff. He found that the difference was also tied to the movement of the planets. Now you ask why would they do this...well if there is a difference, and there is, then Einsteins's theory is in trouble and you know who prints the textbooks. There's your answer.

>>36712 >Furthermore, electromagnetic waves are really just geometric rotations in Spacetime. When an electromagnetic wave propagates, what is actually happening is a rotational oscillation of the electromagnetic field bivector F in spacetime This reminds me very much of Dewey B. Larsons Reciprocal System of physical theory He says everything is motion and that twist of spacetime create everything (I think Have that right). Now this is of course called stupid and here, https://rationalwiki.org/wiki/Reciprocal_Theory they tell you how they have completely disproved it. But...I think they take some things out of context They also use earlier works of his which are more fleshed out in later books and papers. They even use equations of other people to damn Larson. Larson did some very significant things. He predicted certain astronomical type stars before they were found. (I think I have this somewhat right)His theory appears to explain the properties of materials based on their twist?. Like specific heat and lots of other properties. The site, meant to complain about him, says quantum physics explains all of chemical matter combinations HHAHAHHA yeah if you have the life of the universe to do the math. but Larson lays this all out. Even if it's wrong he explains, and can make predictions, of a lot of stuff, in a very easy manner that fits together with a few postulates. https://reciprocalsystem.org/dewey-b-larson I'm not so sure Larson is right(and I'm not smart enough to say) but, his formulation of how to attack the problem seems to be of value. An interesting idea he has, matter is in our universe sucked into another in black holes and blasted out in the mirror universe, same here, and these large jets of matter are where matter comes from. Star formations do seem to bear this out or so I read somewhere long ago.

>>36708 Thanks! You've filled in the details that Mead simply glossed over in that informal chat (+ my clear misinterpretations of his words). Yes, much simpler! Thanks, Axial. >Side note: Is it possible to include math like this picture on here in text instead of me using github with markdown and pictures? Apologies but not as far as I know, Anon. MathJax isn't supported on IBs that I'm aware of. Codeblocks and simple formating is about all you get here. https://alogs.space/.static/pages/posting.html <---> Let's move this to /meta pls, Anons Haha, this is extremely interesting to me, but we are all clearly-derailing our Actuators thread. I should have seen that coming a mile off with that question, so my fault entirely. :D >=== -minor edit

>>36712 >Furthermore, electromagnetic waves are really just geometric rotations in Spacetime. When an electromagnetic wave propagates, what is actually happening is a rotational oscillation of the electromagnetic field bivector F in spacetime. Where did you learn that? Because it just answered a question I've had since High School

>>36673 >Coreless motors are far better for robowaifu, imo. Back to actuators. Axil you said this but I'm not sure this is true nor can I say it is not. But I can game the logic why this might not be so. My confusion is the return path problem. I do understand that Halbach arrays focus magnetic fields but...I see this as changing the magnetic field into a sort of ellipsis or egg shape. Yes there is a very strong concentration in front of it but, does it not have a return path for the magnetic fields? To the best of my knowledge Halbach arrays do not create monopole magnets. I can't imagine it does. I see the magnetic field exactly analogous to electric circuits. The current (magnetic field strength) being alike and if you have a high resistance in the path (low permeable materials..air) then you are lowering the magnetic field strength throughout the whole circuit. Even if you focus the magnetic field you still are going through air in the return path, and air's low permeability means you are choking down your magnetic field. "If" you have a permeable material providing the return path it will increase the field strength over the WHOLE path. I also take issue, for cost reasons, on your use of neodymium magnets( and yes I fully acknowledge you brought that up, clearly and directly). I'm not in any way faulting the ease, performance, feasibility, just cost. In my mind switched reluctance is the only way to go because of the dirt cheap cost. They make the majority of motors and transformers with electrical steel for a reason. It's cheap. For me, one of the major overriding things to watch is cost. A waifu no one can afford is wonderful but of little use. My dollar figure I would like is $2,000 but more likely it will end up at $3,000. But that is affordable. I suspect the compute/electronics will cost $1,500 and more likely $2,000 so that doesn't leave a lot of coin for all the rest. You also said that the compute for inductive reactance motors was troublesome. Now they've been saying that for a long time and I think it's become a catch phrase that was once correct but I don't believe this is true any more, exactly Because now you can get a cheap micro-controllers that will do all the compute very fast for less than $9(or cheaper depending on form/function). With the ESP-32 you'd need about 20 to control 300 actuators equivalent to human muscles. Further about permeable materials. Example-You have two magnets and stick them together such that they are attracted. "If" you add a permeable material around the outside of them connecting the end of one and the beginning of the other...will not the attraction between them be much higher due to the completion of the magnetic circuit? An addendum that might be of great use to all actuator and motor driver schemes. Don Lancaster's Magic Sinewaves This is some really crafty stuff. Don has managed to find a way to use spikes of on-off MOSFET's. The sequence of spikes in actuality, with harmonics, add up to a very good sine wave even though it's made up of a bunch of sharp on off signals. The only harmonics in the end result are high frequency so can be easily filtered. Here's a link asking about them where they also provide links to Lancaster's work. https://electronics.stackexchange.com/questions/11844/don-lancasters-magic-sinewaves#12502 Magic Sinewaves Library https://www.tinaja.com/magsn01.shtml Lancaster is a very smart guy who has written a whole lot of dead tree books and articles on electronics, computing, etc.

>>36607 >ne main problem with a Free Space Halbach is the lower efficiency due to leakage flux and weaker field strength on the active side. This is your general Halbach Array with no return path consideration My apologies. What I wrote I did so before seeing this. I don't know how I missed it, but I did.

I don't know if anyone has heard of this guy he's old school dead tree publishing but I expect a lot of older guys who were interested in electronics have. Don Lancaster. I haven't looked at his stuff in a really long time but used to religiously read all his work. He did a stupendous amount of writing in electronics magazines. An absolute golds mine of all sorts of electronics, robotics stuff. Well I found he passed away by looking for his work on a"magic sinewaves" I commented on above. While looking at some of his other articles I found something I had mentioned here "somewhere" before. Grays code or binary codes that can use a few lines on around wheel to provide very accurate position sensing on rotating machines, actuators, etc. The link is on this page https://www.tinaja.com/hack01.shtml go down to Hardware Hacker Columns #73-87 HACKAR4.PDF and get the link. The article is on page 80.2. If you are into this sort of thing, massive intelligent broad range info on radio wavers, electronic, computing and all other sorts of interesting stuff, I recommend you download his work before it's gone. I have no idea whose hosting this, his kids maybe? I "thought" I had copies of this but searched and, I can't find them so I need to copy all his work before it disappears.

>>36941 F Have no idea who that is, but I'm glad there is interest in preserving his stuff. I dream of our robowaifu's AIs one day being able to sift everything available to find hidden gems for our current needs, engineering or otherwise. Cheers, Grommet. :^) >tl;dr Save.everything.

>>36944 >Have no idea who that is SERIOUS LEGEND I've been going though and saving everything. So much good stuff. Very relevant. All sorts parts interface tricks, Driver tricks. I'm going to post a "field's" super easy calculate link in the motors from him. He put out articles for 50??? years. A long time. He wrote for all sorts of what were major magazines before the internet. I don't even think you can imagine before the internet. Nut & Volt, Electronic Design, Electronics Magazine, there was one that was almost all ads but had a few articles that the ads paid for called Computer Shopper. It was like 3/4 to 1 inch thick in large format like Shotgun News (you may not even know what that is)of all sorts of computer parts and electronics. Huge. It was cheap because the ads paid for the magazine. Like a buck. It used to be fairly difficult to get what you can get with a couple keystrokes now. And with AI that will become even easier. To find out stuff I used to wander through huge stacks of bound older magazines in the Univ. library. Looking through print indexes to find stuff.

>>36949 He sounds amazing. What a career this Anon must've had. I'm sure I must have seen some of his stuff in a bookstore or something. Also, I found this page on his site: https://www.tinaja.com/ebksamp1.shtml Glad you're saving his stuff, Anon. Anything in specific you think would be the most-important for Anons here on /robowaifu/ to know about his stuff? Say a 'Top 5' list or something? Cheers. <---> BTW: Can we please continue this in /meta : ( >>36952, ... )? We're derailing the Actuators bread, IMO. --- https://hackaday.com/2023/07/02/saying-goodbye-to-don-lancaster/ https://www.youtube.com/watch?v=GiI2ayNVDQg >=== -add'l hotlinks -/meta note