[lovelj]

What would be better is a powered caster. By offsetting the steering axis but having it rotated 90 deg from your design you can achieve true Holonomic omnidirectionality. The steering axis imparts a velocity that is orthogonal to your rolling axis. No matter what the configuration of the pods, you can instantaneously move in any direction. There is a nice closed form solution for the inverse kinematics. We built a munition loader for the navy using this approach. I've debated about trying it on a FIRST robot with 3824. Good summer project. I've got a publication on it if anyone is interested