Control Systerm Design And Trajectory Tracking Experimental Study Of Four Wire Driven Parallel Mechanism

Wire driven parallel mechanism is a new type of parallel mechanism that replaces the traditional link by the cable. This type of new mechanism has simple structure, strong carrying capacity, flexible working space, easy to implement, and so on. Owing to these configurations,wire driven parallel mechanism is more widely used in practical engineering. The invention of wire driven parallel mechanism is an important supplement of parallel mechanism family, and it greatly expands the application field of parallel mechanism. However, it is urgent to be solved that control method and control precision of wire driven parallel mechanism, before extension and application in various industries. The main research contents of this paper include:The positive and inverse kinematics modeling of four-wire driven parallel mechanism is established. The simulation results show the positive and inverse algorithm are verified. Based on Lagrange method, the dynamic model is established, which provides the model foundation for the design of the control system.A robust and resist disturbed auto-disturbances rejection controller (ADRC) is designed considering nonlinear, strong coupling and MIMO characteristics. The simulation analysis shows that the controller can realize the high precision trajectory control of the wire driven parallel mechanism.The open CNC system hardware and software design are constructed with industrial PC and DMC motion control card as the core. In the hardware, master-slave control structure that NC is embedded PC mode is selected. The motion control card connects with the servo drive by the DMC interface function. In the software, based on the Visual C++, the special control interface of the four-wire driven parallel mechanism and the universal G code control interface software are completed.The initial position of the four-wire driven parallel mechanism is calibrated based on the nonlinear least squares method. The influence of kinematic parameters error on the movement precision is predicted. The control parameters such as the interpolation points and the pulse command of the trajectory tracking experiment are determined, and then the stability control of the straight and circular trajectory are realized.