Bilateral control for fine processing using virtual grasping/manipulating robots

In this paper, a bilateral control method using virtual grasping/manipulating robots is proposed. In the proposed system, a human operator handles two master robots, and two slave robots grasp and manipulate an object cooperatively at remote location. Concretely speaking, one master robot is utilized only for controlling manipulating motion of slave robots and the other is utilized only for controlling grasping motion of slave robots. Virtual grasping/manipulating robots are defined for making the connection between the motion of master grasping/manipulating robots and the motion of two slave robots. The motion of virtual grasping/manipulating robots is calculated in grasping/manipulating mode space, respectively. Discrete Fourier transform (DFT) matrices are utilized as matrices transforming each robot space into grasping/manipulating mode space. Bilateral control is realized in virtual grasping/manipulating mode space. The proposed bilateral controller, which decomposes grasping/manipulating motion, makes it possible to move an object precisely and to grasp an object with suitable grasping force. The validity of the proposed method is shown by the experimental results.