Abstract
To automate bead grinding tasks by industrial robots, compliant motion of a grinding tool is necessary. However, almost industrial robots are designed on the basis of position control schemes and are not appropriate for force control tasks. In order to solve the problem, this paper proposes an active tool holder which adjusts the tool position independently of robot motion. The developed active tool holder consists of a brushless DC motor, a ball screw and a parallel links mechanism. The translational motion of the grinding tool is realized by the compact mechanism. In order to realize the compliant motion, a stiffness control system using non-linear force feedback was designed. The system can change the stiffness of the tool holder according to its position and enables the effective bead grinding task. The developed system was applied to a simple bead grinding task to confirm the effectiveness of the proposed method.
