Stability Analysis and control of under-constrained cabledriven parallel robots with visco-elastic cables

Cable robots are known for their large workspace characteristic. However, large workspace requires lengthy cables which results in the increase of system flexibility. This flexibility produces internal dynamic which challenges the rigid model based controller. In this paper, the dynamic equations of cable robots with viscoelastic cables are obtained. Then, Feedback Linearization (FL) method is used to provide a linearized dynamic error for the closed loop model of the system with rigid cables. Using the Lyapunov criterion, the stability analysis of the flexible system with the rigid FL controller is performed. It is shown that considering a small damping coefficient and employing the rigid FL controller, the system stability can be guaranteed. The optimal control gains are obtained using LQR method. The effectiveness of the control approach is proved through simulation. Furthermore, in order to show the effect of cable stiffness and damping coefficient on the end-effector vibration and tension oscillation another simulation is conducted.

کلیدواژه ها:

Cable-driven parallel robot ، Feedback Linearization ، LQR ، Lyapunov