The parallel robots exhibit some outstanding properties on the repeatability, stiffness and force-to-weight ratio compared with serial robots. 6-DOF parallel robots have been utilized in various applications and the research on control design has attracted the attentions of researchers. However, the current Cartesian space path tracking performance of the parallel robots cannot meet the growing requirements from industry. In this paper, a dynamic sliding mode control (DSMC) scheme combined with the position-based visual servoing (PBVS) method is proposed to improve the tracking performance of the 6-Revolute-Spherical-Spherical (6-RSS) parallel robot based on the measurements from the optical coordinate measuring machine (CMM) sensor. By employing the CMM sensor, the pose of the parallel robot in Cartesian space can be estimated and incorporated in a closed-loop visual servoing control scheme in real time. The stability of the proposed DSMC has been proved by using Lyapunov theorem. The real-time experiment tests on a 6-RSS parallel robot demonstrate that the complex 6-dimension trajectory tracking can be achieved with high-accuracy. Compared with the classical kinematic level controllers, the proposed DSMC exhibits the superiority in terms of tracking performance and robustness.

与串行机器人相比，并行机器人在可重复性，刚度和力重比方面表现出出色的性能。6自由度并联机器人已在各种应用中得到了应用，控制设计方面的研究引起了研究人员的关注。但是，当前并行机器人的笛卡尔空间路径跟踪性能不能满足工业上日益增长的要求。本文提出了一种动态滑模控制（DSMC）方案与基于位置的视觉伺服（PBVS）方法相结合的方法，以提高基于6圈-球形-球形（6-RSS）并联机器人的跟踪性能。来自光学坐标测量机（CMM）传感器的测量结果。通过使用CMM传感器，可以估计平行机器人在笛卡尔空间中的姿态，并将其实时纳入闭环视觉伺服控制方案中。利用李雅普诺夫定理证明了提出的DSMC的稳定性。在6-RSS并行机器人上进行的实时实验测试表明，可以高精度实现复杂的6维轨迹跟踪。与经典的运动水平控制器相比，提出的DSMC在跟踪性能和鲁棒性方面表现出优越性。