Teams With Mecanum Wheels

[Ken Stafford]

[quote=Joe Ross]190, 211, and 357 are the teams that I know that competed with their mecanum wheels. Several other teams (mine included) played around with them but did not compete with them.

Just a quick comment here. Mecanum wheels can lead you to field-oriented controls. We (190) used this--357 did not, don't know about 211. Our veteran drivers were initially very reluctant to try field-orientation, once they tried it, they all loved it and never used the over-ride switch to return to robot-orientation. Basically mecanum wheels allow you to ignore the conventional front and back orientation of your 'bot (since the robot can move equally well in any orientation). Once you've accepted this there is really no reason to have your driver controls move the robot "forward" or "backward". On our controls, forward on the single joy stick always meant "down field/away from driver" regardless of the orientation of the robot, pushing the stick to the left aways moved the robot to the driver's left, etc. The orientation (yaw angle) of the robot was controlled initially by another joystick where right movement meant "spin CW", left meant "spin CCW". (We have since included this function into twisting the single stick.) The cool thing about field-oriented controls is that say you want to travel directly from a "loader" to an "offload station" but need to have the robot at different orientations. With our controls you simply push the stick in the straight line direction you need and while transiting (via a straight line), you simply twist the stick CW or CCW until the orientation is correct. While twisting, the robot track remains a straight line. It is very cool to drive! Certainly makes for a unbeatable defensive robot. It is not particularly difficult to program but you do need 4 accurate wheel encoders and a stable yaw sensor.

GOOD LUCK!