/robowaifu/ - Actuators For Waifu Movement Part 3

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Actuators For Waifu Movement Part 3 Kiwi 12/06/2023 (Wed) 01:18:16 No.27021

(1stl thread >>406 2nd thread >>12810) Kiwi back again with a thread for discussing actuators to move your waifu! Part Three! Let's start with a quick introduction to common actuators! 1. DC motors, these use brushes to switch the ferrous core electromagnets on a rotor to rotate its magnetic field relative to surrounding magnets! They're one of the cheapest options with an average efficiency range of 30 to 90%. Larger DC motors and motors with higher turn counts are more efficient. 1.5 Coreless DC motors, by removing ferrous materials, losses from hysteresis are almost eliminated, dramatically increasing efficiency to nearly 90% even in small motors. Eliminating the ferrous materials reduces flux focusing, resulting in weaker fields and higher speeds. 2. Brushless DC motors (BLDC), these use a controller to switch the electromagnets on a stator to rotate the magnets of a rotor! Without brushes, they have the potential to be more efficient with higher power density compared to DC motors. Their efficiency and behavior vary depending on the algorithm and sensors used to control them. Coreless brushless motors exist but are rare and only used for very niche applications. 3. AC motors, a wide and incredibly varied category. They all rely on AC’s frequency to control them. With single phase AC motors relying on shaded poles, capacitors, or some other method to induce a rotating magnetic field. 3 phase AC motors naturally have a rotating field which usually gives them higher efficiency and power density. Notably, most AC motors are brushless. The most commonly used brushed AC motor is the universal motor, which is 4. Stepper motors, brushless motors with ferrous teeth to focus magnetic flux. This allows for incredible control (stepping) at the cost of greater mass, subsequently giving them higher rotary inertia. Usually 50 to 80% efficient depending on control algorithm/speed/and quality of the stepper. Due to their increasing mass production (& ubiquitous low cost controllers), they have appeal as a lower cost alternative to BLDC motors if one carefully designs around them. 5. Coiled Nylon Actuators! These things have an efficiency rating so low it's best to just say they aren't efficient. (0.01% typical, 2% achieved under extremely specific conditions in a lab.) Though they are exciting due to their incredible low cost of fabrication, they’re far too slow and the energy requirements are nonsensical. https://youtu.be/S4-3_DnKE9E https://youtu.be/wltLEzQnznM 6. Hydraulics! These rely on the distribution of pressure in a working liquid to move things like pistons. Though popular in large scale industry, their ability to be used in waifu's has yet to be proven. (Boston Dynamics Atlas runs on hydraulics but it's a power guzzler and heavy) Efficiency varies wildly depending on implementation. They would work great for a giantess! 7. Pneumatics, hydraulics lighter sister! This time the fluid is air! This has the advantage in weight. They aren't capable of the same power loads hydraulics are but, who wants their waifu to bench press a car? (Too loud and inefficient for mobile robotics.) 8. Wax motors, hydraulic systems where the working fluid is expanding melted (commonly paraffin) wax! Cheap, low power, and produce incredible forces! Too bad they're slow and hard to control. 9. Explosion! Yes, you can move things through explosions! Gas engines work through explosions! Artificial muscles can be made by exploding a hydrogen and oxygen mixture in a piston, then using hydrolysis to turn the water back into hydrogen and oxygen. None of this is efficient or practical but it's vital we keep our minds open! Though there are more actuators, most are derivatives or use these examples to work. Things like pulleys need an actuator to move them. Now, let's share, learn, and get our waifu moving! Servos! These use an actuator and sensor to control motion. DC, coreless DC, and BLDC motors are the most commonly used actuators for servos in mobile robotics. Potentiometers or hall effect sensors are the most commonly used sensors to detect rotary motion in servo systems. >Soft muscles (pneumatic system) with origami-inspired skeletons: https://youtu.be/OJO4FP0DXgQ[ >Printed pneumatics (TSA can also be used instead of pneumatics for actuation.) https://youtu.be/_X0rDW6NQ58 >Using sugar as soluble support material for printing silicone muscles: https://youtu.be/L0Z0-y3qpNk >Cavatappi artificial muscles (hydraulic coiled nylon hybrid): https://youtu.be/yXAJGH5s4cs https://youtu.be/MpCFumHFZvU https://www.designnews.com/automation/cavatappi-robot-muscles-have-5-times-strength-human-muscles >Twisted string actuators (TSA) Be extremely careful when choosing your strings. They will be put under extreme strain and must be durable. https://youtu.be/N4VMoYFrusg https://youtu.be/hFuzQ4ed-t0 https://youtu.be/J26y1nn7JMM https://youtu.be/zYrHGMiqC9A https://youtu.be/PABVsuV7Y1M https://youtu.be/tP9B3aqc4CI https://youtu.be/Y1uceDzhjKY >Continuous ransmission (CVT) / torque converters https://youtu.be/kVPjhmTThPo https://youtu.be/cd2-vsTzd9E https://youtu.be/c9e2y-5DMNc https://youtu.be/PEq5_b4LWNY >=== -edit subj

Edited last time by Chobitsu on 12/06/2023 (Wed) 03:06:55.

Axial 02/05/2025 (Wed) 12:09:29 No.36607

>>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.

Chobitsu 02/06/2025 (Thu) 02:27:47 No.36652

>tfw i'm getting smarter just lurking this thread rn. :^)

Grommet 02/06/2025 (Thu) 08:49:21 No.36663

>>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.

Grommet 02/06/2025 (Thu) 08:57:09 No.36665

>>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.

Axial 02/06/2025 (Thu) 10:56:15 No.36672

>>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)

Axial 02/06/2025 (Thu) 10:56:27 No.36673

>>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)

Chobitsu 02/06/2025 (Thu) 12:47:06 No.36677

>>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

Edited last time by Chobitsu on 02/06/2025 (Thu) 19:57:26.

Grommet 02/07/2025 (Fri) 02:21:13 No.36705

>>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.

Grommet 02/07/2025 (Fri) 02:51:26 No.36707

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.

Axial 02/07/2025 (Fri) 03:00:28 No.36708

>>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?

Grommet 02/07/2025 (Fri) 03:05:16 No.36709

>>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.

Grommet 02/07/2025 (Fri) 03:20:01 No.36710

>>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.

Grommet 02/07/2025 (Fri) 03:28:54 No.36711

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.

Axial 02/07/2025 (Fri) 03:40:40 No.36712

>>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.

Grommet 02/07/2025 (Fri) 04:27:28 No.36713

>>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.

Grommet 02/07/2025 (Fri) 05:15:54 No.36716

>>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.

Chobitsu 02/07/2025 (Fri) 07:51:35 No.36720

>>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

Edited last time by Chobitsu on 02/07/2025 (Fri) 07:57:17.

GreerTech 02/08/2025 (Sat) 12:43:36 No.36759

Grommet 02/11/2025 (Tue) 01:52:08 No.36872

>>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.

Grommet 02/11/2025 (Tue) 02:04:39 No.36873

>>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.

Grommet 02/13/2025 (Thu) 06:42:51 No.36941

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.

Chobitsu 02/13/2025 (Thu) 08:06:51 No.36944

>>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.

Grommet 02/13/2025 (Thu) 12:27:19 No.36949

>>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.

Chobitsu 02/13/2025 (Thu) 12:51:57 No.36951

>>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

Edited last time by Chobitsu on 02/13/2025 (Thu) 14:30:39.

Grommet 03/11/2025 (Tue) 02:25:05 No.37425

I found something that I didn't know while looking at some of Robert Murray's stuff. This is one of those things you might want to keep the back of your mind as it may come in handy. I found that Silicon Carbide diodes have very high temperature ratings, they have almost no time to switch from on to off and are more efficient with less leakage. Silicon needs a finite amount of time that can cause problems. They appear to be close to indestructible compared to silicon. The reason this appeals to me is I'm interested in switch reactance actuators and all other sorts and you are going to have to have diodes to stop high reverse currents AND, while I do not know this for sure I expect that we can build our own. They are in a class called Schottky diodes and these were made a really long time ago with a semiconductor like silicon carbide and a metal. "if" you have 300 muscle circuits you are going to need a lot of them and you can buy silicon carbide super cheap by the pound for abrasives. Maybe you could use this stuff??? I'll look around and see. It beats trying to solder 600 or so diodes. These you might could silk screen them on. https://en.wikipedia.org/wiki/Schottky_diode https://www.electronicdesign.com/technologies/power/power-supply/discrete-power-semis/article/21193085/schottky-diodes-the-old-ones-are-good-the-new-ones-are-better I "think", not sure at all, that you can also make transistors from SiC...hmmm.... not sure. Something to think about.

Robowaifu Technician 03/11/2025 (Tue) 04:17:13 No.37433

>>37425 Any idea how well they handle high voltages?

Grommet 03/11/2025 (Tue) 08:26:33 No.37441

>>37433 >high voltages Yes noted for it's high voltage handling. They are using them in auto motors because of this. Far better than typical silicon. Not that I completely understand this but normal P-N type silicon diodes have a built up charge barrier when reversed. It takes energy and time to reverse this and allow current to flow. Schottky diodes do not have this and are therefore faster and if I remember correctly more efficient. Note there is Schottky diodes made of silicon. I'm mostly talking about the SiCarbide ones though to be specific but I of course do not rule out others that I may not have heard of yet. SiC has very high temperature ratings. I wonder. One of the metals used to make Schottky diodes is tungsten which of course has very high melting point. I wonder if you took some SiC powder and electroplated it with tungsten would that work????

Grommet 04/21/2025 (Mon) 00:35:46 No.37623

>>37425 > Schottky diodes...silicon carbide and a metal....you can buy silicon carbide super cheap by the pound for abrasives. Maybe you could use this stuff??? The Llama 3.3 70B AI is very skeptical of this approach. It doesn't say you categorically couldn't do it, but it seems to discourage the idea this can be done. I'm still not so sure that some sort of functionally useful Schottky diode can not be made economically. After all these were made in the early days. This is likely one of those things I'll have to keep n the back of my mind and slowly research and maybe something will pop up.

Chobitsu 04/21/2025 (Mon) 17:39:43 No.37627

>>37623 Interesting, Grommet. Do you have a good feel yet for why it's spitting that negative response back?

Grommet 04/24/2025 (Thu) 09:12:49 No.37754

I've been hunting for this paper. I found it when the site was down and thought it very good but when I went to find...arrrggh. It's about using black sand, basically iron oxide you dig up in a yard or find in a steam to make electrical parts, including motors and actuators. I told Chobitsu you could do this but didn't have a paper that backed it up like this one. The reason I couldn't find it was I forgot the name and the title didn't have iron or F2O3 or whatever. So searching all over didn't help. But I finally did. It's great and a way to cheaply get material to make your own motors and actuators using "dirt" as the permeable material. Like the electrical steel in motors and transformers. Here's the link and on that page is a download for, "Digging Dirt: on Inductors: Experiments with Custom Magnetics Made from "Black Sand."" https://hpfriedrichs.com/radioroom/inductors/inductors.htm One thing he found was that while iron oxide is not the best permeable material he found that as long as it was not over driven with too much magnetic field strength it had very low Magnetic reluctance which like resistance in circuits but for magnetics. So good efficiency at low field levels. This is fine for us because you can get fairly strong forces with even this material. This is well worth reading even if you don't plan to use iron oxide as a material.

Grommet 04/24/2025 (Thu) 09:15:54 No.37755

>>37627 >spitting that negative response back I think purity and maybe not crystalline enough. Basically rough material. I'm guessing so don't count on that as definitive. It could be wrong though. People made crystal radios in the old days from rough stuff. I've caught AI's saying wrong things more than once. But they are sooooo useful, mostly.

Chobitsu 04/24/2025 (Thu) 23:59:13 No.37764

>>37754 That's really pretty cool, Grommet. Stuff like this gives me hope that humans will be able to recover from catastrophe should the need arise. Cheers. >>37755 Yeah, that seems to make sense to me.

Grommet 04/25/2025 (Fri) 06:45:15 No.37780

>"Digging Dirt: on Inductors: Experiments with Custom Magnetics Made from "Black Sand."" I want to say one more thing about this article. If you look at the price of motors, actuators, etc. they are high as hell (for the numbers we need for real looking waifu's)and with the recent tariff troubles they are only going to get higher. I think that there is no way possible to economically make a robowaifu if you buy all these actuators. So the article above may not be exactly what you need but it's a great good start and shows you can do this with found materials and some methods. I've been looking at synthesizing iron oxide nano-particles. There's a LOT of work on this. Some of it doesn't look extraordinarily complicated though I just started looking. I don't know all the numbers yet but the reason its so popular as a research subject is these have great permeability and a very high level of magnetic flux before they choke. This paper looks REALLY GOOD for making these. A quick preview I see no super odd chemicals needed or specialized equipment. "A Milestone in the Chemical Synthesis of Fe3O4 Nanoparticles Unreported Bulklike Properties Lead to a Remarkable Magnetic Hyperthermia" bulklike It uses PEG which can be bought as a laxative Polyethylene Glycol Powder for Solution (MiraLAX) and Iron oleate I don't know for sure yet but oleate is a surfactant so I expect you make the above from it and iron I don't think this will be a huge problem. None the less if you can start with regular black sand from the ground or streams and then try more powerful stuff. I only started looking to make this stuff when I priced permeable powders and they were high. China had them reasonable but the shipping cost alone was like $90 for a couple kilos. Now, way higher.

Chobitsu 04/25/2025 (Fri) 16:25:46 No.37802

>>37780 >I think that there is no way possible to economically make a robowaifu if you buy all these actuators. Now you're getting it, Anon: actuators have always been the highest-cost single factor category of constructing pleasing & effective robowaifus (solely b/c the software coming from here is FREE [as in beer & speech: MIT-licensed (so, actually free speech! :D ]). This is one of the highly-important reasons why Kiwi, myself, and other cadres are so pleased with the ideas of Tensegrity : ( >>37672 ) for humanoid robotics. Amongst the many, many benefits this approach brings to us here on /robowaifu/ , significantly-reduced actuation costs (primarily due to significantly-reduced mass : >>4313 ) is a BIG one. <---> I like this guy's stuff, Grommet. Thanks for introducing us here to him! Cheers, Anon. :^)

Edited last time by Chobitsu on 04/25/2025 (Fri) 18:34:42.

Grommet 05/02/2025 (Fri) 07:22:01 No.38110

Artificial Muscles from Fishing Line and Sewing Thread haines2014 abstract https://www.science.org/doi/10.1126/science.1246906 paper https://sci-hub.ru/10.1126/science.1246906

Chobitsu 05/02/2025 (Fri) 12:32:33 No.38118

>>38110 Seems like we've been over this before, and it didn't seem to turn out positive. Didn't one of our guys actually do a fair bit of realworld experiments on this idea? Regardless, I'm sure the potential there is real. It's simply going to take a professionally-manufactured set of components to pull off well, AFAICT. The >tl;dr being this isn't well-suited to typical Anon's garage lab approaches.

Grommet 05/04/2025 (Sun) 02:01:28 No.38154

Crystal Structure and Magnetic Properties of Fe3O4 Nanoparticles Using Iron Sand as a Raw Material for Mercury Removal https://jonuns.com/index.php/journal/article/view/1240/1234 The key here is not mercury removal but making nano magnetite (Fe3O4) from black sand you can dig up. Nano magnetite (Fe3O4) has very high superparamagnetism. Means that magnetic fields are channeled through it at a very high rate and the material has high saturation figures to these fields and it makes for very high power solenoids or electromagnets. An it's totally non toxic to boot. They use this for contrast in medical scans. People swallow it. Here's a paper that goes over, roughly, the main methods of making this stuff. Magnetite nanoparticles Synthesis methods – A comparative review IJCRT22A6681 https://ijcrt.org/papers/IJCRT22A6681.pdf It's a good brief review and if you are at all interested in making magnetic actuators, from scratch, you should download it. That and the paper using black sands directly above. It also has the references in it to learn the methods. There are many. A paper needed is a way to make a flexible rubbery like conductive material. Combine these and I think you would really have something.

Grommet 05/04/2025 (Sun) 07:53:00 No.38166

I found a really, really good video on this, Making ferrofluid from scratch https://www.youtube.com/watch?v=6L8yUY-doNc

Chobitsu 05/04/2025 (Sun) 20:14:10 No.38186

>>38166 Great information, Grommet! Thanks & cheers. :^)

Robowaifu Technician 05/04/2025 (Sun) 20:20:12 No.38187

>>37780 What application are you trying to synthesize them for? Are there any requirements for size or crystal structure of the nano particles? If so what are the tolerances?

Grommet 05/05/2025 (Mon) 08:25:12 No.38224

>>38187 >What application are you trying to synthesize them for? Magnetic amplifiers, solenoids and electric motors Are there any requirements for size or crystal structure of the nano particles? If so what are the tolerances? They are typically looking at 5-20nm. For our purposes I suppose we could do with larger. A lot of research is for medical use. The magnetic particles provide high contrast for medical imaging equipment. Me, I want to tag along on their research. I will not say that I can write a symposium on all the effects of this but I get generally that they have very high permeability, they are able to sustain high magnetic fields without them choking and becoming a high resistance. As a general rule higher permeability means higher frequency and much smaller equipment with larger forces. Concentration and force per magnet field force is the big one. They also have a benefit that they can operate as one large mass, though I'm not exactly sure about all of the relevance of that but I believe it's directly related to the other traits I just listed and, I think it lowers eddy currents which are wasted energy. If you are making magnetic amplifiers from them you can use a much smaller (very small)DC voltage to control a very large AC voltage and current. This could come in very handy. They used these to control theater lights and battleships turrets in WWII. They are VERY robust. There's, I think, two different forms they're looking for. One is better than the other but I think both "not bad". I believe the one with less oxygen F3O2, a guess, is better, but I could be wrong. I have briefly looked at the papers but I can't remember all of the details off hand. The data is in the papers and in the video that I linked. The two forms have different crystal forms.

Grommet 05/05/2025 (Mon) 08:40:20 No.38225

I may have it wrong. I think this is the form you want 2 Fe3+ + Fe2+ + 8 OH− → Fe3O4↓ + 4 H2O So more oxygen??? I note that the synthesis in the video he worried about too much oxygen as he was stirring upsetting the reaction to a less desirable state. I think it might produce side reactions that are none of the above. FeO maybe??? I;m not a chemist but took a couple chemistry courses so I know just enough to know, that I know very little. Like Barbie says,"Chemistry is hard". Here's links on these, https://en.wikipedia.org/wiki/Iron_oxide https://en.wikipedia.org/wiki/Iron_oxide_nanoparticle

Grommet 05/05/2025 (Mon) 08:47:03 No.38226

If I could easily get powders online I wouldn't waste my time with this but the people supplying this are typically only interested in selling you tons and you have to sign up, talk to reps, it's a huge annoyance and on their part they don't care. They want to sell the already made cores not the powders. The ones who list just powders, with price, want an ASTRONOMICAL fee for them. It may very well end up that using black sands or some chemically made version of them is the best path even if the material is inferior. I wish I could get a couple kilos of Sendust alloy powder. That would be good. China will sell it to you but the shipping is a killer and now, with tariffs and trade disputes...not going to waste time on that.

Robowaifu Technician 05/05/2025 (Mon) 13:38:09 No.38232

>>38224 Nile red's video looks like your best bet for making them at home. If you are really interested in the biomedical applications you could try cultivating magnetotactic bacteria for their magnetosomes. You would have more control over chemical composition, size, and shape, but it is a slow and energy intense process and it is not a mature process. If you are making them on a small scale those might not be huge issues. https://microbialcellfactories.biomedcentral.com/articles/10.1186/s12934-020-01455-5

Grommet 05/05/2025 (Mon) 18:59:05 No.38242

>>38232 >interested in the biomedical applications I have zero interest in biomed. Only noted it as this is the a lot of why they are researching this.

Grommet 05/07/2025 (Wed) 00:44:18 No.38277

I found these brief articles. It's a great summary of why to use permeable materials for actuators, motors, etc. Very concise and short with a lot of info using graphs. https://www.horizontechnology.biz/blog/what-is-sintered-soft-magnetic-material https://www.horizontechnology.biz/blog/iron-powder-types-permeability Earlier I noted that one of the advantages of nano-materials is that they acted like one solid mass. I didn't really understand thta til I saw this i the article, "...However, what if your design requires higher perm and saturation? A logical transition is to the iron phosphorus material now with the benefit of advanced compaction technologies. The higher densities - up to 7.3 g/cm³ will promote higher perm - up to 4000 coupled with higher saturation induction..." So "maybe" the nano materials act like a compressed solid without actually sintering it into a solid, or so I read it that way. Maybe I seem to be blathering away a lot about this but in my opinion it;s at the very root of making efficient actuators. Now if a way can be found to make coils using these powdered materials without actually winding them up... Lots of resources here, https://www.horizontechnology.biz/soft-magnetic-composite-resources?hsCtaTracking=bf1123d2-dd65-4967-a84e-b0297046fa01%7C22279883-1ca0-4188-85a0-15819ac3a283

Grommet 05/07/2025 (Wed) 01:07:01 No.38279

One more I find myself looking at. It's a coil gun link. Directly applies because it;s all about getting the most force from magnetic systems. https://coilgun.info/theorymath/saturation.htm

Chobitsu 05/07/2025 (Wed) 15:54:24 No.38294

>>38277 >Maybe I seem to be blathering away a lot about this but in my opinion it;s at the very root of making efficient actuators. Nah, it's fine Anon. We all get it, I think. I'm hopeful that @Axial will return soon to pick up his thread again (cf. >>36271 ). Your investigations into these things may have bearing there. >Now if a way can be found to make coils using these powdered materials without actually winding them up... This. Cheers, Grommet. :^)

Grommet 05/09/2025 (Fri) 03:13:42 No.38312

>>38294 >Axial I personally believe that any non return path, no permeable material, motor/actuator will always be inferior to the one with a return path. My understanding is it's like an electrical circuit and the permeable material is like a less resistive wire and a return path that has none, only air, is like a big ass resistor in a circuit. You will have way less magnetic force. If it;s such a good idea then why does every single electric car makers motors have permeable material to concentrate the magnetic field? Now it "may" be possible to use rare earth magnets and use purely attraction to the coils but REM cost a damn fortune and kill the price/performance level. Interesting factoid https://www.nextbigfuture.com/2025/05/nvidia-james-fan-proposes-physical-turing-test.html "1.5 million parameters is all that is needed to capture the sophistication of the human body for humanoid robot training." Anyone here know what that means exactly? A guess, 1.5 million bytes of data to monitor??? Or could it be nodes in an AI and if so what sort of compute would be needed for this. Anyone with a rough guess? Not a perfect guess but maybe one order of magnitude. I'll throw some numbers out there for fun. (not to be used for insurance claims nor do I accept responsibility for inaccuracies) A ESP32 microcontroller has 600 DMIPS. So at 1.5 millon parameters we have 400 operations per parameter and that's just a regular microcontroller. Looks as if one microcontroller could handle the whole entire waifu. Note that the whole body is not going to be moving so it could be less compute. Hell lets be generous and make one for gross body movement and one each for legs, head. You're still easily in range.

Chobitsu 05/09/2025 (Fri) 07:49:18 No.38314

>>38312 >I personally believe that any non return path, no permeable material, motor/actuator will always be inferior to the one with a return path. I don't have sufficient training in EM/Field-theory (yet) to know any better one way or other, but the instincts of my mind's imagination tell me this is the correct take. >why does every single electric car makers motors have permeable material to concentrate the magnetic field? We have a video linked here on the board somewhere about the remarkable stator, etc., design of the newer Tesla motors. It would be nice to know more about the manufacturing techniques used to produce them! There's also another video about the 'print-in-place' method used behind an even more-sophisticated, smol'r design motor (in response to your 'make coils:no winding' comment posted above). <---> >"1.5 million parameters is all that is needed to capture the sophistication of the human body for humanoid robot training." <sauce: bull's a*rse With all due respect to those esteemed researchers, I think this is yet to be determined! :D We simply can't say something like this definitively yet, I deem. But what we can say definitively is that the eminent Carver Mead has done extensive research on so-called Neuromorphics (being the founder of the field back in the day) [1]. And what Dr. Mead, et al, says is that the "intelligence" of creatures gets 'pushed out' to the periphery of their body structures. In other words, for us humans, a very large part of our own sensorimotor / kinesthetic "understanding" happens not within our brains -- but within our peripheral spinal-column + limbs neural tissue! Certainly such a model of reality seems to me (at least with merely a surface, cursory view on these matters) to warrant against using just a simple, "LLM-like" discourse as the correct method to approach these problemspaces with. /$0.02 . <---> As to your back-of-the-napkin estimate of the h/w power needed for our robowaifus to be safe & successful, effective & pleasing waifus... again, hard to say yet. OTOH, I'm rather-confident we can, in fact, solve the basic kinematic needs with a reasonably modest array of smol SBCs & MCUs + sensors, etc. [2] Its the very language/emotions & world-modelling/judgement problems themselves that may need an inordinate amount of compute to manage well, I think. Stay tuned. I think most of us plan to use some sort of home server setup for offloading robowaifu compute. I personally mean rather to have it all onboard in the nominal case, and will be satisfied (at least at first) with having conversations not much more extensive than her saying "Chii?", "Chii!", "Hideki?", "Hideki!!" After all, teaching her about life & things is where all the fun is! :DD Cheers, Grommet. :^) --- 1. (cf. >>12828, >>12857, >>12861 ) 2. with the fundamental proviso that the software itself running on said hardware is highly-efficient, realtime-compatible, C++ & C code!

Edited last time by Chobitsu on 05/09/2025 (Fri) 09:09:07.

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