ゲインスケジューリング制御を用いた空気圧サーボ系の動摩擦補償法

抄録

Friction force that pneumatic servo systems inherently possess varies considerably while the system is working. Therefore, changes in plant dynamics are inevitable. In addition, due to its nonlinearity and negative velocity-characteristics, stick-slip often occurs near a target position. This paper proposes gain-scheduled H_∞ control of a pneumatic servo system with linear matrix inequalities (LMI) for compensating the influence of dynamic friction force on control performance. In the proposed approach, a linear parameter-varying (LPV) system is constructed by modeling a coefficient of dynamic friction, which varies under operation, as a time-varying parameter. The coefficient of dynamic friction is on-line estimated using the friction force model that we have previously proposed. In order to reduce deterioration of the control performance and avoid stick slip, controller dynamics is adjusted based on the estimation as it can follow the plant dynamics. The effectiveness of the proposed control system is experimentally confirmed by comparing with conventional H_∞ control.