Vision-based adaptive control of a 3-RRR parallel positioning system

The macro positioning stage with high-precision and rapid positioning ability plays a crucial role in the macro-micro combination positioning system. In this paper, we develop a practical method for the control of a 3-RRR planar positioning system using online vision measurement as feedback. In this method, a monocular vision system is established to accomplish highprecision online pose measurement for the 3-RRR manipulator. Additionally, a robust and operable adaptive control algorithm,which incorporates a fuzzy controller and a PI controller, is employed to achieve precise and rapid positioning of the 3-RRR positioning system. A series of experiments are conducted to verify the positioning performances of the proposed method, and a conventional PI control algorithm is utilized for comparison. The experimental results indicate that using the proposed control approach, the parallel positioning system obtains high precision and shows higher efficiency and robustness, especially for the time-varying positioning system.