Quote:
Originally Posted by nxtsoccer
I know what an encoder is (measures/counts rotations), but I don't see how that would be beneficial to a holonomic drive.  |
Encoders are beneficial to a holonomic drive because these drives largely rely on the kinematics involved with the wheels going at very precise speeds. Since an encoder can measure the revolution (in this case of the drive axle or an axle coming off of the gearbox), it is the proper sensor to close that loop and accurately control the speeds of all of your wheels.
If a mecanum drive is coded for voltage control (no closed loop, just set the motors to a given voltage), you could have a situation where your driver commands the robot to drive straight forward, but only 3 of the 4 wheels are driving close enough to the same speed. That fourth wheel driving at a different speed than the other three will cause a slight rotation/strafe in the driving, resulting in a robot that will not be able to drive in a straight line. This is why speed control of the wheels is very important and encoders can be used to achieve this.
Good luck, and I hope you guys have success with your off season projects! It's this kind of work that will prepare your team for a successful season.