气动三自由度并联平移型机器人的同步控制

气动三自由度并联平移机器人由固定平台、动平台、3个辅助臂和3个驱动臂组成,3个辅助臂约束机器人动平台的转动,3个气缸驱动机器人动平台沿x, y, z方向的运动。根据并联平移机器人的机械结构及运动特征,得到动平台的运动学正解和逆解。在并联平移机器人的运动控制中,不仅要减少单个驱动臂的跟踪误差,还需考虑驱动臂间的运动协调性。由于气体的可压缩性、负载的时变性和摩擦力等因素,精确的驱动臂模型难以建立,因此针对单个驱动臂设计了线性自抗扰控制器;此外,根据机器人结构特点设计基于驱动臂跟踪误差分解组合的协调控制器,解决了运动协调的问题,进一步减小了空间轨迹的跟踪误差。实验证明了该控制策略的有效性。

Synchronization Control of a 3-DOF Pneumatic Translational Parallel Robot

The mechanical structure of the pneumatic 3-DOF translational parallel robot consists of a fixed platform, a movable platform, three auxiliary limbs and three driving limbs. The three auxiliary limbs structures constrain the rotation of the movable platform, and the three cylinders act as drivers to realize the movement of the movable platform along the x, y, z directions. According to the mechanical structure and motion characteristics, the forward and inverse kinematics solutions of the moving platform are obtained. For motion control of the pneumatic translational parallel manipulator, not only the tracking error of a single driving limb needs to be reduced, but also the coupling of driving limbs and the motion coordination need to be considered. Due to the compressibility of the gas, the time-varying load and the friction, it is difficult to establish accurate model of the driving limb, a linear active disturbance rejection controller is designed for single driving limb. In addition, according to the structural characteristics of the manipulator, a coordination controller based on decomposition and combination of the driving limb tracking error is designed to solve the problem of the motion coordination, further reducing tracking error of space trajectory. The effectiveness of the control strategy is verified by experiment.