Dynamic Modeling And Control Of A Four-Wire-Driven Parallel Robot System

The current schemes for outside-wall cleaning of the buildings mainly include "spider-man" suspended in the building roof, climbing cleaning robot, and railway glass rubbing machine. In order to overcoming the shortcomings of the schemes, a concept about the working platform driven by 4 wires in parallel for outside-wall cleaning is introduced, and a wire-driven parallel robot with a high-safety factor, a low cost, a labor intensity and an high efficiency is obtained.On the basis of the previous work including investigation of the related mechanism issues when the robot works with a slow speed, dynamic modeling and control of the electromechanical coupling system for the 4-wire-driven parallel robot has been studied in detail with the consideration of the influence of cable mechanics on the performance of the robot system. The detailed work is as following:At first, the scale model of the working platform driven by 4 wires in parallel for outside-wall cleaning is given, the catenary model for wires at an initial steady posture is studied, and the inverse kinematics is solved after the motion trajectory of the end-effector for the mechanism is planned.Then, a test prototype is set up according to the requirement of the mechanism parameters for the scale model, and the experiments for the trajectory control of the end-effector based on inverse kinematics are implemented using an open-loop position control for actuators. The experimental results have shown that cable mechanical characteristics have some innegligible impacts on the precision of the trajectory control of the end-effector.Furthermore, with the consideration of cable mechanics, the virtual prototype model of the mechanical part of the 4-wire-driven parallel robot is built under the environment of ADAMS software. The simulation results have indicated that the precision of the trajectory control of the end-effector can be improved if cable mechanics is considered, however a control law is needed to increase the precision.Finally, the dynamic model of the electromechanical coupling system for the4-wire-driven parallel robot is set up by the combinational control simulation ofADAMS and MATLAB/Simulink. The simulation results have shown that the precision of the trajectory control of the end-effector is improved further.The research outcomes will provide theoretical basis and simulation data for the hardware-in-the-loop simulation of the 4-wire-driven parallel robot and development of the working platform driven by 4 wires in parallel for outside-wall cleaning.