Active Suspension - Trying to build a Bose style suspension for an RC car

[@wildgophers91]

Thanks so much for reporting your findings even if they aren't "successful".

[@ambrosewest3817]

the design is brilliant. i was looking at this type of design and following the bose system. the issue that always made this design challenging for me was not the design it self (in terms of concept) ... it was was the energy and the dynamics of it required ... this suspension in my opinion would require very high amps, maybe a 48v system running on capacitor as a quick charge and discharge, and a very large battery pack to back it up ... is suppose it could be easier to adapt it for a slower moving vehicle ... just some thoughts... looking forward to seeing how you overcome the challenges and reach your goals ... good luck

[@salmanzafar86]

I have been trying to build a high bandwidth active suspension as well thank you for this video…

[@julienboucaron9780]

Nice video. Your hydraulics diagram reminds me of Citroen car suspension, most of those with mechanical control valves on each wheel to obtain a flat ride. I remember that Moog in F1 is providing very fast hydraulic actuators.

[@IndeterminateDesign]

Yes, it's very similar. It's actually the diagram for the Williams F1 active suspension system. The moog valves are amazing. When I did the F1 gearbox I found a lot of information on their servo valves. I think they were retailing for around $7k each a couple of years ago.

[@stefanguiton]

Excellent video!

[@IndeterminateDesign]

Thank you very much!

[@bytesandbikes]

I really like that bobbin winding setup. Saved for later! 😀

[@IndeterminateDesign]

Thanks! There's a really elaborate coil winding machine this guy made: kzbin.info/www/bejne/fXvGgpmAa6-HkMk. I had to pull myself back from building an entire machine for a handful of coils

[@ericlotze7724]

@@IndeterminateDesign major mood

[@rcmod642]

I tried after watching the boss's active suspension video, but I gave up because needed too much coil. I wish you success.

[@IndeterminateDesign]

Thanks! I'll keep at it and see how far I can go.

[@xXDaReasonXx]

my midnight stoner suggestion is to use a form of cantilever suspension arms to adjust the range of motion to what suits the power draw best. Its a very interesting concept and ive always been fascinated by the bose system. The benefits if you could properly measure the ride height in real time on a scale vehicle would be astounding for race chassis'.

[@IndeterminateDesign]

The cantilever suspension setup is a good idea, similar to how I had the servo's setup on my first active suspension truck. Its hard to say whether the weight from the variable cantilever setup would outweigh the additional windings in the voice coil. Ultimately, I really want to try the 3 phase setup, because we can get more travel range and power, but just haven't had the time to pull something together.

[@Liberty.Francis]

Great project. I hope you can figure it out...

[@IndeterminateDesign]

Thanks! I hope it's something that ends up being possible.

[@weareallbeingwatched4602]

You should just epoxy the wire as it goes onto the bobbin with an immersion dispenser - a plastic dispensing beaker or mixing pot with the wire thrreaded through a pair of holes in it, at the bottom end, so the wire gets tacked up, and you can then wind the bobbin continously, without voids.

[@IndeterminateDesign]

That's a good idea. The layer by layer process is super messy and difficult to start between the layers.

[@loukiankostovic9022]

In your video, you mentionned hydraulic active suspension. Is this kind of system controlled by a servo or a stepper motor or is controlled through actuators too? If not, trying different pistons diameter-range ratio to adapt to the force of the actuator might an option I think. Your content is very rich, thanks a lot for all your work! Luck for the next steps!

[@IndeterminateDesign]

Thanks so much. Yeah, the hydraulic based active suspension would be similar to what Williams used on the FW15 F1 car. Basically an electric motor driving a hydraulic pump and a series of servo valves. All of that would have to be custom designed, but I think it’s doable with a resin 3D printer. F1 teams and some FSAE teams have done something similar to what you’re mentioning with piston sizes and valving. They cross linked the shocks and built a valve body that was essentially an analog computer to control everything. I may try a very simplistic version of this.

[@DallusDaPwnage]

I thought heat would become an issue, I deal a lot with 3 phase motors and actuators in an industrial setting. I think a electrical hydraulic system would be optimal but on a RC scale I can't see it working. One thing that's been in my head for a while is having a vacuum system (like the 2J) on the wheels alone and having the body being aerodynamically neutral, I don't think it would work well on an RC scale but on like a velomobile scale I think it could work. I'm just a dumb breakdown electrician though so my knowledge is mostly experienced based with a heavy bias towards simplicity.

[@IndeterminateDesign]

I think a vacuum based system would be interesting and the simplicity is appealing. The hydraulic system would be so much more complex and heavy. I'd spend a year just sorting that out. I feel like at this point I have to go bigger to deal with the heat and weight issue, otherwise I'm not going to increase the performance of the RC car.

[@ericlotze7724]

I for one would LOVE a Velomobile / Quadricycle E-Bike type thing with some amazing active suspension lol More cost for the frame (and probably materials) to an extent, but having more room to shove components would be neat!

[@RunesLegacy]

You could do magnetic ride suspension instead, maybe using your coil to magnetize the fluid. They sell the magnetic fluid used in the real systems.

[@IndeterminateDesign]

That's been on my list for a while to try. It's been difficult to find the good MR fluid. It's about $350 for 250ml. I've thought about buying some old GM shocks to harvest the fluid from them instead. Most of the reasonably priced MR fluid I've found is the stuff for educational purposes with 10-20% nano particles. The stuff used for suspensions is about 30-40 percent nanoparticle iron, and it's much finer particles.

[@qwer.ty.]

What about FRIC (Front-to-Rear-Inter Connected Suspension) to minimize your energy consumption?

[@IndeterminateDesign]

That's definitely on the list of something I want to try, maybe even with a gas spring. I've played around with it a bit for my streamliner project and I really need to buy some small air cylinders or something because I found friction from the seals to be a real issue.

[@nuttyDesignAndFab]

a big issue here is that you'll have to constantly support the weight of the car with your actuator, which is no bueno for electric actuators. Recall that the energy being converted by an actuator is back emf * current, while the energy wasted is R*current^2, thus constant force with no motion is just burning energy. I know this is going back to position control, but consider using a 3 phase motor and a worm drive in line with the spring? I think position control would be good if you think of it in terms of it reacting to steering and accel/deccel commands for like keeping the stance of the car.

[@IndeterminateDesign]

Shouldn’t the spring carry the weight of the car? The way I was planning on running it would be just to act as a damper, albeit a damper than can add or subtract energy from the system. I wanted to see how powerful I could make the actuator, because ideally on rough terrain I’d want the actuator for a short period of time exert ~2x the cars weight. I have thought about using a 3 phase brushless motor and a ball screw, similar to how many cars perform brake by wire. They make some really cool 5mm ball screws but they are pricey, but they are backdriveable.

[@RupertArmstrong]

Do you think it would be possible to use a magneride style setup instead, where you include iron in the hydraulic fluid and adjust the dampening through an electric current that passes through it? it would be lighter and may use less energy then motors.

[@IndeterminateDesign]

It is definitely possible. I’ve talked to an individual that has attempted this with RC shocks. The challenge being finding the proper magnetorheological fluid. Most of the stuff online is for educational purposes and has too little iron and too large of particles. It’s also usually mixed with kerosene instead of a silicone oil. I need to find either an old GM shock to drain or pay $200 for a liter of the right stuff.

[@salmanzafar86]

Use a ball screw with a rotary electric motor it should work fine and add water cooling if needed.

[@IndeterminateDesign]

I’ve thought about that a lot. I’m concerned about getting small enough back-drivable screw. I really need it to be a force driven actuator versus my earlier position based actuators.

[@Lukaey]

Maybe you could get away with a geared motor and a multithread high pitch spindle. The gearing would make the system less backdrivable. But it should be fast enough.

[@IndeterminateDesign]

That’s a great idea. I’ve been trying to think of ways of having some sort of gearing system. I like how compact a screw drive is. I’ve been thinking of using a rack drive system but it’s difficult to achieve a significant reduction without a large gearbox.

[@micultimy91]

Next time, go to a scrapyard, buy a complete ABS unit, teardown the electronic module out of it and use the coils. Thank me later 😜 For the size you want, those coils are appropriate.

[@IndeterminateDesign]

That’s a good idea. I think I have an old BMW one I can try to take apart. I’m working on a 3 phase one too, but more work involved with that.

[@weareallbeingwatched4602]

Why not wind the voice coil with butted ends to linearise the magnetic field lines?

[@IndeterminateDesign]

What do you mean by butted ends? That sound interesting, but I'm still not sure I can get as consistent force as I would with a 3 phase linear motor setup.

[@weareallbeingwatched4602]

@@IndeterminateDesign basically vary the thickness of the motor and quantity of the windings so that the magnetic forces are linearised within the working range. Would also have a look at how hard drive head actuators work.

[@martylawson1638]

Belt drive from a drone BLDC motor should get you similar force/inertia ratios as Bose got. Packing will be more difficult, but the parts are off the shelf. Not surprizing that the company that bought the BOSE active suspension isn't going after the automotive market. As a tiny startup, they'd have 100% less chance of success than BOSE. (which is already a big automotive supplier) Active seat suspension and vibration control are still significant markets that could develop the tech enough for cars to be an interesting application again.

[@IndeterminateDesign]

Belt drive is a great idea, or even a cable drive system. I think it could be made quite compact. Yeah, the more I read about the Bose technology the less I felt like it was a viable product. I think their most useful patents were around the control algorithms for an active suspension system.

[@ericlotze7724]

@@IndeterminateDesign I don’t know if it is exactly a fit, but along this line of thought, “James Bruton” used BLDC motors and belt and/or Gear Reduction for adding “springy-ness” to their Open Source robot quadroped, “OpenDog” ‘s limbs. That may be worth a look for inspiration (if you don’t already watch his channel that is! )

[@CarlosRodriguez-zr6dx]

Im my opinion way too complicated for what it really is , the design for functionality it’s just way too extra and NOT overkill at all because it didn’t work