2000 Volume 18 Issue 8 Pages 1166-1172
In this paper, a new wheel mechanism for holonomic and omnidirectional mobile robots is presented. The caster drive technique is one of the feasible solutions to allow a vehicle to have holonomic and omnidirectional mobile capability with standard wheels. The caster drive is applied to a differential drive mechanism. A drive unit equips with two drive wheels driven by individual motors. The rotational stage, driven by the third motor, is mounted on the drive unit with its rotational center locating at the off centered position from the mid point of the two driving wheels. The translational position and velocity of a mobile base are controlled by the differential-drive mechanism executing a caster like behavior. The orientation of the mobile base is controlled by the rotational stage decoupled with the translational motion of the drive unit. The vehicle 3DOF are controlled by the three motors, hence the system includes no over constraint problem. In addition, the drive mechanism is very simple and could be implemented by using a traditional differential-drive mechanism.
