An apparatus and method for direct physical interaction between a person and a general purpose manipulator (10) controlled by a computer. The appartus, known as a collaborative robot or 'cobot' (10), may take a number of configurations common to conventional robots. In place of the actuators that move conventional robots, however, cobots use variable transmission elements (20) whose transmission ratio is adjustable under computer control via small servomotors (50). Cobots (10) thus need few if any powerful, potentially dangerous, actuators. Instead, cobots (10) guide, redirect, or steer motions that originate with the person. A method is also disclosed for using the cobot's (10) ability to redirect and steer motion in order to provide physical guidance for the person, and for any payload being moved by the person and the cobot (10). Virtual surfaces, virtual potential fields, and other guidance schemes may be defined in software and brought into physical effect by the cobot (10).
NON-HOLONOMIC USER INTERFACE FOR A ROBOT