液压并联机器人力/位混合控制策略研究

The aim was to propose a combined position/force control scheme for Stewart parallel platform's interacting tasks with environment or human body based on force sensor and vision system. The vision system included a high resolution camera and a laser range finder which aimed at providing global position information. To enhance the performance of industrial tasks interacting with the environment, a novel hybrid position/force control algorithm using exteroceptive vision system for hydraulic Stewart parallel platform was proposed. A two control-loop scheme was designed for interacting tasks, and gravity compensation was demonstrated to balance the disturbance. A full experimental system was built and a number of experiments were performed. The whole experimental system consisted of two parts, which was the hydraulic parallel manipulator and the docking simulation system. Firstly, a relative position tracking experiment was conducted to investigate the manipulator's high-speed tracking ability. Movement commands of ±100 mm/s in y axis and ±80 mm/s in z axis were given to actuate the manipulator. From the experiment result, the relative position tracking errors of y and z axes were both smaller than 10 mm. And then the dynamic docking experiment was performed to investigate the interacting performance with the target object of the proposed combined position/force control law, where the movement speeds of the docking simulator was driven along the y axis at 50 mm/s and z axis at 40 mm/s. In dynamic docking experiment, the contact force of the manipulator was controlled within 300 N, the hydraulic manipulator could track and dock with the moving target reliably and quickly. The above two experiments were conducted and the experiment results demonstrated the effectiveness and stability of the proposed algorithm.