基于模糊控制理论，研究水平运动的4自由度欠驱动机器人位置和姿态控制问题。平面4自由度欠驱动机器人是具有冗余度和欠驱动双重特征的复杂二阶非完整系统，利用主动关节和被动关节加速度之间的耦合作用控制被动关节的运动，同时实现机械臂末端的轨迹跟踪和末杆的姿态控制。根据分层控制思想，提出双模态模糊PID复合控制算法，针对两个子任务分别设计控制器。通过Matlab和ADAMS的联合仿真验证算法的有效性，在基于可编程多轴运动控制卡的试验台上实现平面4自由度欠驱动机器人的位置和姿态控制试验。仿真和试验结果表明，所设计的模糊PID复合控制器对平面4自由度欠驱动机器人末杆的位置和姿态控制是可行、有效的。

Based on the fuzzy control theory, the position and orientation control of a 4-DOF planar underactuated robot is investigated. The 4-DOF planar underactuated robot is a complex second order non-holonomic system with redundancy and underactuation. Using the coupling effect between the acceleration of passive joint and that of active joints, the motion of the passive joint is controlled. The trajectory tracking of end point and the orientation control of end link of robot are achieved simultaneously. A double fuzzy-PID compound controller is designed for the two subtasks based on the hierarchical control idea. The controller is verified by the co-simulation in Matlab and ADAMS. The experiment of the position and orientation control of the 4-DOF planar underactuated robot is realized on the experimental test bed based on PMAC controller. The results of simulation and experiment indicate that the fuzzy-PID compound controller is feasible and effective for the position and orientation control of 4R horizontal underactuated robot.