What a difference new wheels make. Big wheels! I spent ages trying to figure out why he flops around sometimes, then lowered power (Kp) to see if it helped – seems like if I keep Kp lower than 16 it doesn’t freak out. So, I think the draw from the motors is what’s creating […]
Read more "BalanceBot One Lives!"
Poor BB1 hasn’t been able to balance since I refactored him with dual motors. I thought it was motor speed related, but larger wheels arrived today and still no good. The large wheels make it more apparent that he is almost stable except the direction of the motor ‘flips’ every now and then, driving him […]
Read more "Balancebot Algorithm Redux"
I hooked up the motor controller with the wrong polarity by stupidity! I got too excited about all this and instead of taking my time I pushed forward in a rush. Dead motor controller. Silver lining – I know I can output 5V PWM from an Arduino already, and I have a throttle now .. […]
Read more "Slider trike delayed!"
Slider trike is partially assembled! I was sad that I have stalled on putting this together, and realised it was because I don’t have batteries worked out. I don’t want to spend $400 on lithium right now for 48v 20Ah (easily an hour of fun!), and I don’t want to waste money on crap batteries […]
Read more "Slider Trike Partially assembled!"
Ok, so BB1 got all reconfigured again – now with dual motor drive! He still can’t stand (torque seems good, speed maybe not enough? I’ve ordered some more motors, geared faster). When they arrive I’ll swap them over and see what the improvement is like. I did a little reading and saw some notes about how a speedier motor almost always trumps a torquier motor. I look forward to seeing if more speed can get this balancing (come to think of it, even with the motor stuck on full speed, it’s not very fast … ).
There is a problem that causes the IMU to stop responding when flopping from side to side (and, hence, motors going full positive to full negative). That leaves the motor stuck on, and the various while()’s in code never complete, so it’s essentially dead but with 100% motor. While plugged into USB (only) I can’t get it to happen, so I think it’s something to do with driving the motors hard creating voltage/current drops enough to kill the IMU.
I’ve tidied up his code a lot using bits from TKJ and Bajdi (it looks like Bajdi just borrowed TKJ’s anyway!) and modularized it a bit. At least the angle calculation, PID generation, and motor control are all in different functions now. I’d love to clean it up more.
I just found these CHEAP motor controllers .. ordered one just in case, because at $14 .. wow – the specs suggest it would run my unicycle easily. Will have to do some testing!
This week was big for poor BB1 – during a demo some of his magic smoke escaped. I did a quick smell test and determined that something on the VIN circuit had popped. I looked into it more and discovered that I had wired everything up backwards in the first place. So I had battery […]
Read more "Balance Bot 1 Upgrade"
One of the steps on the hobby fronts was to buy a hub motor for an ebike project! Happily I’ve just ordered an ebike conversion kit from http://em3ev.com – their “500W DD” kit. Many happy users on endless-sphere are putting a lot more than 500W through these, so it seems like a good place to […]
Read more "Hub Motor ordered!"