Experimental investigation of variable scaled bilateral control

Recently, the field of real-world haptics which deals with force information has been widely researched. In order to acquire haptic information which is fed back to operator from a remote environment, a master-slave system is constructed and bilateral control is implemented to the system. Transmitting haptic information has many advantages for tele-operations, human support system and so on. In the tele-operation, operator mainly manipulates the instruments only based on visual information conventionally. Due to the lack of haptic information, there are some possibilities that the instruments and the environment are broken. So, by applying bilateral control to the tele-operation system, they can operate on the basis of not only visual information but also haptic information, and consequently it leads that the accuracy and safety in the manipulation dramatically become better. As one of the applications of bilateral control, macro-micro bilateral control has been proposed so far. This control method intends to transmit haptic information between the different scaled objects. Therefore, operators can feel the reaction force as if they are touching the real micro or macro environment. It is effective for the manipulation where they cannot operate directly. However, most conventional researches are focused on the constant scaling gain. Considering the actual manipulation, the scaling gain should be changed arbitrary by operators in real-time. To tackle this requirement, variable scaled bilateral control is proposed, and the control system is constructed based on the effect of the order of the disturbance observer, which is experimentally investigated in this paper. The validity of the proposed method is verified by experimental results.