robertstuart

Member Since: October 26, 2011

Country: United States

  • Since all of my self-balancing robots, http://twopotatoe.net, use wheel encoders, I normally can’t offer much useful advice for your robot. Nevertheless, I have a few comments:

    • You are right about keeping the weight high. However, with an effective algorithm the weight can be kept quite low. Witness FivePotatoe: https://youtu.be/9pQcHJDpBWg6. As you can see, it also allows self-righting which is kind of neat. SixPototoe—https://youtu.be/ShRu4HaDT_M—also has this characteristic.

    • Most balancing robots—but not mine!—use a PID algorithm, which can often be made to work quite well. However, if you follow general control theory practices, the “I” should not be needed. But yet, most people need it to get the robot to stay up at all. Why is this? I think it is the speed of the robot that hasn’t been added in to the calculations. Essentially the “I” should be removed and the speed of the wheels should be substituted. This is not easy but doable. I think this is why your robot is falling over. Nevertheless, some PID adjustments could fix it as well.

    • As for the algorithm rate, higher would seem to be better. However, anything much over 100HZ is probably unnecessary since the low pass filter in the IMU makes a higher rate mostly ineffective. In fact, rates as low as 20HZ can work quite well.

    • Motor size is always a problem. If the motors aren’t providing enough power, just up the voltage! Anyway, you work at Sparkfun so replacing motors shouldn’t be a burden.

  • One of my robots can use MaxSonar devices to navigate. The now deleted chain link fences give a great signal but hay bales do not. Other than the barrels, are there going to be any stanchions or the like to navigate by? Also, it would be nice to have a more complete specification on the ramp: its width, height and placement. It could easily be avoided or negotiated on the old course but with the narrower path on the new course presents a particular problem for either strategy. Placing it off-center might help.

No public wish lists :(