A systematic method of hybrid position/force control of a manipulator

The feasibility of applying robot manipulators to complex handling and assembly problems in indus try and space depends on the ability to control manipulators precisely, even when there are uncertainties and variations in the environment. This can be done by giving a manipulator hand sensors that provide information about the progress of interactions with the environment. A method is presented for controlling both the position of a manipulator and the contact forces generated at the hand. This hybrid controller has the feature of permitting trajectories to be specified in a convenient Cartesian coordinate system, while offering advantages over the existing approximate "free joint" methods. An experimental implementation of the controller was developed and used to control two joints of a modified Scheinman manipulator equipped with a wrist mounted force sensor. Data from this implementation are presented along with the results from a simple simulation.