Force control of redundant robots in unstructured environment

B. Nemec, L. Zlajpah
2002 IEEE transactions on industrial electronics (1982. Print)  
In the paper a method for force control of redundant robots in unstructured environment is proposed. We assume that the obstacles are not known in advance. Hence, the robot arm has to be compliant with the environment while tracking the desired position and force at the end effector. First, the dynamic properties of the internal motion of redundant manipulators are considered. The motion is decoupled into the end-effector motion and the internal motion. Next, the dynamic model of a redundant
more » ... ipulator is derived. Special attention is given to the inertial properties of the system in the space where internal motion is taking place; we define a null space effective inertia and its inverse. Finally, a control method is proposed which completely decouples the motion of the manipulator into the task space motion and the internal motion, and enables the selection of dynamic characteristics in both subspaces separately. The proposed method is verified with the simulation and with the experimental results of 4.D.O.F planar redundant robot In the past the Moore-Penrose pseudoinverse [10] has been widely used to resolve the redundancy. It is defined as J · J T´J J T µ 1 where n m. Its "weighted" counterpart [6] is defined as where W is an n¢n weighting matrix. A special form of J · w is when W H, where H is the inertia matrix of the manipulator. Khatib [9] has proven that
doi:10.1109/41.982267 fatcat:grsgsifnnngllmuabxs6d7yfsm