The Inverse Function Approach to Kinematic Control of Redundant Manipulators

An inverse kinematic function for a redundant manipulator is a generalization of the most common form of sensor-driven control for nonredundant manipulators. However, the nonuniqueness of the functions in the redundant case can be used to reduce joint speeds, avoid obstacles, and improve the usable workspace. This paper reviews our work of the last several years on the inverse function approach and discusses the practical considerations that recommend its use. Methods of representing the inverse functions are discussed and compared to the related extended Jacobian technique. Recent results on workspace limits are summarized, and the paper concludes with an indication of possible avenues for future research in the area.