An improvement method of compliance control in pushing operation by mobile manipulator

This paper describes a new control method for pushing operation by mobile manipulator. The mobile manipulator can perform many tasks because it has mobility of the mobile platform and manipulability of the multijoint arms. Therefore, it is very effective for tasks in human environment. Using this advantage of the mobile manipulator, this paper aims at pushing operation in human environment. In pushing operation, stability of a pushing object is very important factor. Also, in the case that a pushing object is a wheelchair, stability is a great factor in the meaning of ride quality. As the method to enhance these factors, there was compliance control in past researches. However, in pushing operation by compliance control, there is the problem of tracking performance because this method does not consider nonholonomic constraint of a pushing object. In this paper, by improving compliance control, the control method is proposed that considers nonholonomic constraint and becomes asymptotically stable to a desired trajectory. By this proposed method, both high stability and tracking performance of a pushing object can be realized in pushing operation. The experiments were carried out in order to verify the validity of the proposed method.