Mechanical Analysis Of Electro-hydraulic Hybrid-Driven Cable Parallel Robot

This thesis is supported by Chinese National Natural Science Foundation,entitled by “Research on dynamic coupling characteristics,control methods and experiments of a modularized reconfigurable equipment of cable-driven parallel robot with electrohydraulic hybrid-driven system”.For electro-hydraulic hybrid-driven cable parallel robot(EH-DCPR),this thesis focus on the kinematics,workspace,coupling dynamics,motion simulations and control schemes.The main work in this thesis is summarized as follows:1.The structure and the reconfigurable process of EH-DCPR is introduced in this thesis,and the workspace and its related problems are researched.The coupling kinematics model of EH-DCPR including driving devices is analyzed,and the statics equilibrium equation is established.Then the workspace of EH-DCPR is searched by Monte-Carlo method in MATLAB.Additionally,the effect of different structural parameters such as weight of end-effector,height of cylinder and angle of mobile modules on the workspace is also discussed.The result is that the reconfigurable characteristics can improve the adaptability of EH-DCPR.2.In this thesis,the coupling dynamics of EH-DCPR is studied,and the accurate dynamics model of a cable is analyzed considering the gravity,inertia force,damping force and elastic of cable.Moreover,AC servo systems is introduced,and the dynamics model of driving system is established on this basis.3.The simulation of obstacle avoidance motion of EH-DCPR in definitive obstacles is analyzed by SolidWorks and ADAMS,and the results showed that the coupling dynamics of EH-DCPR established above is correct.Besides,the elastic of cable could influence the system motion performance and accuracy.The simulation comparison for the coupling dynamics of Lagrange Method and ADAMS show that the coupling dynamics of Lagrange Method is correct,and this is verified by the experimental results.4.According to the characteristics of EH-DCPR,the control system established by independent kinematics closed-loop control strategy is simulated.Additionally,the conventional PID control and fuzzy-PID control are analyzed and compared.The study reveals that the fuzzy-PID control has better control performance,and it was more suitable for multivariable and complicated time-varying system.Furthermore,the experimental system controlled by fuzzy-PID method can get high control precision.