Kiwi Drive and Integrating PID Loops

[GeeTwo]

Originally Posted by jgrindle

According to Inventor the CG rests right behind the back of the opening. When we finalize building it, we will actually have to put some weights in the back, to balance the robot out when we have a full stack on it. Without the weights(With all the Electronics still on it though), the CG will be really close to the center of the robot. This will be because of the Elevator we will be adding, and the built in tote ramp(Sort of like 1902's or 125's) we will be adding to it.

Just eyeballing it, this would mean that the CoG is going to be about 10" from the center wheel, and about 20" from the side wheels. Assuming that you're using encoders and controlling based on speed, this would mean that Jared's scaling of W3 at half of that for W1 and W2 is correct. As your CoG moves farther away from the point where the axes cross, you may find that you will have to scale the side wheels' rotational values (W1 and W2) down a bit to compensate. The amount would be by cosФ, where Ф is the angle between the line from the CoG to the wheel's floor contact and the axle for that wheel.