Almost two years ago, a research team showed that it was possible to get fine motor control from cheap, brushless DC motors. Normally this is not feasible because the motors are built-in such a way that the torque applied is not uniform for every position of the motor, a phenomenon known as “cogging”. This is fine for something that doesn’t need low-speed control like a fan motor, but for robotics it’s a little more important. Since that team published their results, though, we are starting to see others implement their own low-speed brushless motor controllers.
The new method of implementing anti-cogging maps out the holding torque required for any position of the motor’s shaft so this information can be used later on. Of course this requires a fair amount of calibration; [madcowswe] reports that this method requires around 5-10 minutes of calibration. [madcowswe] also did analysis of his motors to show how much harmonic content is contained in these waveforms, which helps to understand how this phenomenon arises and how to help eliminate it.
While [madcowswe] plans to add more features to this motor control algorithm such as reverse-mapping, scaling based on speed, and better memory usage, it’s a good implementation that has visible improvements over the stock motors. The original research is also worth investigating if a cheaper, better motor is something you need.
We have to admit that we raised a wary eyebrow as we first watched [MakerMan]’s video below. We thought it was going to be just another hoverboard hack at first, but as we watched, there were some pretty impressive fabrication skills on display. Yes, the project does start with tearing into a defunct hoverboard for parts, primarily one wheel motor and the battery pack. But after that, [MakerMan] took off on a metalworking tear. Parts of the hoverboard chassis were attached to a frame built from solid bar stock — we’ll admit never having seen curves fabricated in quite that way before. The dead 18650 in the battery pack was identified and replaced, and a controller from an e-bike was wired up. Fitted with a thumb throttle and with a bit of padding on the crossbar, it’s almost a ride-upon but not quite. It seems to move along at quite a clip, even making allowances for the time-compression on the video.
While [Vedder]’s controller is aimed at low power applications such as skate board motors, [Marcos]’s version amps it up several notches. It uses 600 V 600 A IGBT modules and 460 A current sensors capable of powering BLDC motors up to 150 kW. Since the control logic is seperated from the gate drivers and IGBT’s, it’s possible to adapt it for high power applications. All design files are available on the 
That may or may not be [pacificmeister]’s goal with his 
