Abstract
This paper is concerned with a direct teaching/playback method for a hybrid position and force control in a robot manipulation. By adjusting the impedance of the robot appropriately, a teaching operator can manipulate the robot tip easily in free space and constrained space by appling force to a teaching lever mounted at the tip of the robot. The operational force applied by the operator and the contact force acting on the smoothly curved constrained surface are stored in the computer as the teaching data. A given task in the playback process is to make a smooth contact with a constrained surface from the free space and to apply a specified forces while the tip of the robot is moving along the constrained surface. In the playback, the contact force is possible to follow the stored values of the contact force or the different values programmed after the teaching. To keep accuracies of the force control even when the location of the constrained surface is slightly changed from the teaching process, the well-known “hybrid control technique” is applied to obtain control laws. The method is applied to a 2-link vertical articulated direct-drive hydraulic robot. The experimental results affirm the validity of the proposed method.
