In this paper dynamic analysis and robust PID control of‎‎fully-constrained parallel cable driven manipulators are studied in‎‎detail‎. ‎Since in this class of manipulators‎, ‎cables should remain in‎‎tension for all maneuvers in their workspace‎, ‎feedback control of‎‎such robots becomes more challenging than ‎that of ‎conventional parallel‎‎robots and research on this topic especially on robust stability analysis is limited‎. In this paper, structured and unstructured uncertainties are considered in the dynamic model and Jacobian of the robot, and a robust PID controller is proposed for the cable driven parallel robot. To ensure that all the cables are in‎‎tension‎, ‎a corrective term is used in the‎‎proposed PID controlbased on the internal force concept. Then, robust stability of the closed-loop system is analysed through Lyapunov’s second method and it is shown that by suitable selection of the controller gains, the closed-loop system would be robustly stable. ‎‎Finally‎, ‎the effectiveness of the‎‎proposed PID algorithm is examined through experiments on a planar‎‎cable driven robot and it is shown that the proposed control‎‎structure is able to provide suitable performance in practice‎.

Keywords: Parallel cable robots, PID control, Internal force, Stability analysis, UUB stability.

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