Modal state position controller for the Utah/MIT dextrous hand

Control of multifingered robotic hands is a natural example of hybrid control in which contact forces must be controlled without exceeding force thresholds while the fingers are moved to impart motion to an object. A modal state position control algorithm is described which is suited for hybrid manipulation tasks. Position tracking is robust, allowing force control to be executed in parallel according to task requirements. Hybrid control is achieved by the summed actions of the primary position controller and one or more secondary force controllers. The position control algorithm is outlined for both joint-space and Cartesian-space applications. Implementation and performance issues on the Utah/MIT dextrous hand are discussed