Robust fast tracking control for multi-degrees-of-freedom motion system considering torque saturation

Robust fast continuous path tracking control is the important technology for the multi-degrees-of-freedom position control system such as X-Y table, robot manipulator and so on. Especially, large acceleration and/or deceleration torque is necessary for fast continuous path tracking control at its start position and its goal position. Each motor of high speed path tracking control has the torque limitation. This motor cannot always obtain the enough acceleration and/or deceleration torque due to its torque limitation. Hence, in controlling a multi-degree-of-freedom position control system, even if motor torque of only one axis has torque limitation, the actual position response is not equal to the trajectory reference. In fast continuous path tracking control of multi-degree-of-freedom position control system, the position error sometimes increases according to the unknown disturbance torque and inertia variation. In order to overcome these problems, this paper proposes a new robust fast continuous path tracking control algorithm taking into account both the torque saturation and the coordinated motion, which is based on the robust acceleration control using disturbance observer. The proposed method assures the coordinated motion considering the torque limitation. The effectiveness of the proposed method is confirmed by the experimental results in this paper.