A Comparison of Control Algorithms for Redundant Manipulators from Viewpoint of Collision Forces

In the paper some control algorithms for redundant manipulators are compared from the viewpoint of the behaviour of the system during the collision with an obstacle. The emphasis is given to the contact forces and their minimization, and how they can utilize the self-motion caused by the contact forces to avoid the obstacles and to minimize the tracking errors in the task space. A controller which ensures stiff behaviour in the task space and compliant behaviour in the null space has turned out to be the best solution. The efficiency of the particular control algorithms is illustrated the experiments on a four link planar manipulator.