Brushless motors can offer impressive torque-to-size ratios, and when combined with complex drive control and sensor feedback, exciting things become possible that expand the usual ideas of what motors can accomplish. For example, to use a DC motor in a robot leg, one might expect to need a gearbox, a motor driver, plus an encoder for position sensing. If smooth, organic motion is desired, some sort of compliant mechanical design would be involved as well. But motors like the IQ Vertiq 6806 offered by [IQ Motion Control] challenge those assumptions. By combining a high-torque brushless DC motor, advanced controller, and position sensing into an integrated device, things like improved drone performance and direct-drive robotic legs like those of the Mini Cheetah become possible.
First, the bad news: these are not cheap motors. The IQ Vertiq 6806 costs $399 USD each through the Crowd Supply pre-order ($1499 for four), but they aren’t overpriced for what they are. The cost compares favorably with other motors and controllers of the same class. A little further than halfway down the Crowd Supply page, [IQ Motion Control] makes a pretty good case for itself by comparing features with other solutions. Still, these are not likely to be anyone’s weekend impulse purchase.
So how do these smart motors work? They have two basic operating modes: Speed and Position, each of which requires different firmware, and which one to use depends on the intended application.
The “Speed” firmware is designed with driving propeller loads in mind, and works a lot like any other brushless DC motor with an ESC (electronic speed control) on something like a drone or other UAV. But while the unit can be given throttle or speed control signals like any other motor, it can also do things like accept commands in terms of thrust. In other words, an aircraft’s flight controller can communicate to motors directly in thrust units, instead of a speed control signal whose actual effect is subject to variances like motor voltage level.
The “Position” mode has the motor function like a servo with adjustable torque, which is perfect for direct drive applications like robotic legs. The position sensing also allows for a few neat tricks, like the ability to use the motors as inputs. Embedded below are two short videos showcasing both of these features, so check them out.
If you’re wishing these motors were a bit less spendy, there’s good news! [IQ Motion Control] previously released a smaller motor with similar features: the IQ Vertiq 2306. That unit is available in 220KV (low-speed) and 2200KV (high-speed) versions for servo and drone applications, respectively. Check out our earlier coverage of these smaller units and get a feel for their capabilities, and maybe get a few ideas of your own in the process.
The mini cheetah legs are not direct drive
About the spring, I can imagine that in a near future, this kind of technology will replace current spring/dampers in cars..
complete control over softness. easy hight change, super fast reaction.
Even it’s possible scan the road and cancel bumps actively…
but some problems may occur when you turn off the power :)
i think apple has a recent patent for a variable feel keyswitch in a mechanical keyboard. as for cars though, air suspension is a common mod which is more suitable and efficient.
It has already been done, look up this video: https://www.youtube.com/watch?v=3KPYIaks1UY
Although the tech si in my opinion really impressive, they state at the end of the clip that the system was too heavy/costly if I remember correctly.
And as you stated, in case of power failure, you have nothing, which is a no go in these industries.
Power steering?
What about it? Power steering still works when unpowered, it’s just very difficult to turn when stationary
You can always carry a small 4 HP gasoline generator in backseat.
Here’s the F1 take on powered suspension
https://youtu.be/sRB9T2ACPRI
Funny, I just looked this video today! Very interesting and impressive
Jumping over a small obstacle is awesome. Maybe it needs a “turbo” mode, black paint and a wobbly red light.
Awesome! I’m sure over time, and with mass production, it becomes cheaper/lighter and more reliable.
And for power failure and also when you turn off your car, maybe they can use some sort of mechanical position lock in them.
50 years ago, having a fully electric power steering was not possible. But now it’s possible, it’s safe, and the price is reasonable.
The car jumping over the obstacle is spectacular.
You mean like these?
https://www.autoevolution.com/news/how-magnetorheological-suspension-works-8947.html
Should I do what “A” did above and effectively say “nope”, or should I be a good robot and furnish an answer?
Whirr, click, compute, whirr…
Ping! Not nope. Nope is insufficient. Human probably wants answer…
The answer is:
Nope.
But nope because the magnetorheological suspension linked above can only vary the dampening of the system. By applying a magnetic field it changes the way ferrofluid type dampening material goes through channels. More goopy (probably, but not certainly, higher field) means more dampening. The Bose system is effectively replacing the dampers with linear motors (leaving springs in place). The springs take the weight of the car and the linear motors can add or subtract force, thus balancing the car as it goes over rough lumpy surfaces.
To speculate, the linear motors could be of the 3ph permanent magnet type:
https://en.wikipedia.org/wiki/Linear_motor
Error. Error. Robots do no speculate. Fizz. Clunk. Whirrrrrrr. Smoke
$399 ??
$18 on ebay – dc brushless, with optical encoder, with pwm controler integrated. Add PID library for AVR or STM32, done.
Thanks for your insight, please build a demo and share the details.
Nidec 24H motor most likely. The ones described here are way more powerful. Also the Nidec integrated pwm controller has a high minimum torque.
Still, both options are good value for money depending on what you need.
And what does the torque look like on those tiny motors?
mN/m?
Don’t forget the power level these motors are looking at.. You don’t find working brushless motors of this specs anywhere near that cheap. The ESC and encoders are not free either, and you probably need external most of the time… You really can build you own versions with cheap parts if you don’t need the performance, but from a look at the paper specs the motor is in the power range to be at least double your estimate just for the bare motor, Control circuits and encoders probably double your estimate again, and that is all at second hand pre-crashed parts..
To get new separate parts with the right kind of specs isn’t going to be much cheaper… So it all comes down to if you need those specs (skimp and it can be done much cheaper) or can accept the less sleek form factor and you can save a little. But on the whole its actually priced in the right ballpark IMO..
The best way to improve such a motor is to take a cheaper one, and build an open-source controller for it.
Ironically, these are knockoffs of the MIT mini cheta motors (sans planetary gearbox) which was open source to begin with.
There are factories that make similar products with OPEN SOURCE firmware and controller circuitry. based on the open source MIT cheetah. I assume these guys were “inspired” by that to create a closed-source product. pass.
is it available as a raw motor ie sans any electronics? I would love to experiment with it as a wind generator
You can get similar hub motors. See the Mini-Cheetah paper? https://dspace.mit.edu/handle/1721.1/118671
This looks like what Josh Pieper has been building on .io :
https://hackaday.io/project/167845-mjbots-quad
https://www.youtube.com/watch?v=brN2C59aBxU