<title>Systematic control scheme for multiarm robot systems</title>

Abstract

Control of multiple robots has attracted researchers' interests for many years. Problems arise when uncertainty or coordinated motions are involved. This paper investigates several issues related to control of robot systems with multiple arms. We present a systematic control strategy for the coordination of robot motions during homogeneous manipulations. A hybrid force and position control law is used to determine the force and position targets of the object being manipulated. The frictional equilibrium and stability principles are employed in computing the optimal force distribution among the robots. The position targets for the end effector of individual robots are calculated using appropriate transformations which take into account the coordinating constraints. A generalized control algorithm is developed using this strategy and the manipulation can be achieved by specifying a number of external quantities, which describe the nature of the tasks to be performed, as the inputs to the control algorithm. This control strategy is adopted in developing control algorithms for heterogeneous manipulation tasks such as tasks that require robot interchange during the manipulation. In such as task, it is necessary to coordinate the motions between the coordinating robots and a free robot. A hierarchical control mechanism is used in achieving this coordination. The control primitives developed for controlling robots in the homogeneous manipulation can be used in this hierarchical control. The control algorithms have been successfully implemented on a robot system to perform various tasks with good results.