In order to robotize bead grinding tasks, we have developed an active tool holder which adjusts the tool position independently of robot motion. A simple stillness control using force sensor is applied to the active tool holder. The control system is effective for flattening the small unevenness of the weld bead. However, it is difficult to remove large bumps of the weld bead by the control system. To solve the problem, we propose a method to reduce the feed rate of a tool at the large bump.
