[jonathan lall]

I've examined a few controls on crab/strafe drive robots and what seems to be popular is a simple single-stick control that dictates the angle of the wheels. For example, a stick moved halfway to the top-right corner from the centre position would have the robot strafe forward 45 degrees right at half-speed, or whatever the transfer function dictates for that stick position. To turn on axis, these robots often have a knob that simply moves one side forward and one side backward like a typical tank drive system.