As promised I've started a separate thread on this. I had mentioned over at my Alan thread that I was thinking about using hoverboard motors for a rolling base for the full bodies of Alan and Alena. These motors are super cheap at about $25 a piece on ebay. They are 3 phase just like the 3 phase hobby motors for cars and planes. So there should be driver support for them.....well yes and kinda no.
I have been watching a motor controller called the ODrive. Its all open source (hardware and software) and its a dual motor driver. I posted a video of these motors on a grocery cart driving around using hoverboard motors. So I bought an Odrive. I ended up buying a whole hoverboard so I could use the charger, battery and some of the connectors. This one came from Frys and cost $100. Its good upto 265 pounds.
Well now the bad. The ODrive is still a work in progress and not too intuitive. But they have a good write up on how to set them up with the hall effects encoders. All went well until I tried to save out to the board. Over and over again i could not get it to work right. I posted on the forums and got no reply back as to what the issue could be. So after days I began looking for another solution.
I found a great source in china that is making opensource stuff for skate boards. The got 2 single motor drivers. Each one has a standard servo connector and i can use two of them for mixed mode (tank mode). Each board costs $85. So its a bit more than the ODrive ($150 with shipping for the 48 volt ver.)
The name of the board is the FSESC 4.12 50A Based on VESC 4.12 from Flipsky ESC. And can be found here: Flipsky ESC
This controller can be completely programmed with their really great software..automatically figures out all the poles for the phases. Set up the frequency for the pwm and even have shut offs for voltage mins etc. They have a good youtube channel with vids on how to set up everything.
I have the video of the break down of the hoverboard done. As soon as I get these control boards I will be doing tests with the ezb to control them. Then I'll put together a final video and post here.
Other robots from Synthiam community
Leversofpower's Roboquad Redux
Tmesserschmidt's Topsie The Easy To Build Robot Dog
Since we are using it for robots and not racing skate boards I'm going to set these up as FOC. They are super quiet and a bit slower than the BLDC mode. But you get instant full current to move your load from a dead stand still to moving with out taking too long. The trade off is speed, but thats not what we are trying to achieve.
I also am excited about ramping. You can ease in and out of your speed. There is also braking which is important if your robot finds itself on a hill. And reverse. Alot of these controllers do not reverse, because right now they are just set up for skateboards and you really only go one direction. But this has reverse. You can set a separate reverse speed as well.
FOC: FOC is a different method of spinning up the motors. It was originally developed for high-performance motor applications that are required to operate smoothly over the full speed range, generate full torque at zero speed, and have high dynamic performance including fast acceleration and deceleration.
So if i understand you correctly, it can hold at zero speed? Example on a grade or hill.? Can it Segway?
You sure can...rock solid...you can also decline or incline at a set speed.....at the expense of battery consumption:)
....and if thats not enough...they have an app for android phones to monitor in real time....
Looks like Alan may stand on his own some day with only 2 wheels.
I promise, i will stop now and leave you alone to play. It's after 6 here and i will finish up work soon.
Looks like boards go on order tomorrow. Poor credit card this month, especially if Dj comes through with the rest of the parts we need.
...hahahaha yeah my wallet is smoking....
...interesting....with position control...you can turn these into massive servos!
Good Morning All. Everything's on order ! Hopefully all will arrive in a week and at the same time.
You are saying these can work as servos?
Can you imagine the massive shoulder and elbow servos using these? Instant full torque without gearboxes. Once I get the new hover board, I may buy a replacement motor to see if it can be hacked.