Realization of "Law of action and reaction" by multilateral control

In recent years, the realization of a haptic system has been strongly desired in the fields of medical treatment and expert's skill acquisition. The key point of haptics is to realize a vivid presentation of reactive force, particularly in applications that involve touching action. In this paper, a realization of the "law of action and reaction" by multilateral control is introduced. First, an analysis and a design of bilateral control based on the disturbance observer are discussed. A disturbance observer is a basic technology for quarrying of disturbance torque and attainment of robust acceleration control. This paper shows that a four-channel controller which is composed of position control and force control in the acceleration dimension is decomposed into two modes: common and differential modes. A design of bilateral control is treated as position and force control in a single joint. The proposed method generates a good realization of reactive force for the slave side at the master side in bilateral force control. Second, bilateral control is extended and multilateral control is generalized. Multilateral control is designed similarly as bilateral control based on the modal decomposition. Robots with a haptic ability will have an important role in human adaptive mechatronics.