Optimal Variable Damping Control for a Robot Carrying an Object with a Human

In the near future many robots will do tasks in our life such as home automation, agriculture, medical engineering and so on. In this situation, the robots work in close space to human. The robots, therefore, should be humanfriendly and designed considering human characteristics. One of the important functions for the human-friendly robot is to cooperate to the motion of the human. We have considered a task of carrying an object by a robot and a human as the example of the human and robot cooperation [1]. To develop the controller of the robot, we have investigated the characteristics of the cooperative task by two human operators. The results of the investigation are implemented as the robot controller. In this report, it is shown that the cooperative characteristics of human can be regarded as a damper model whose damping factor changes optimally so that a cost function becomes minimum. The effectiveness of this model is shown experimentally.