A Real-Time Fault-Tolerant Constrained Control Scheme for Elastic Cable-Driven Robots

This article proposes an integrated fault-tolerant control architecture for unidirectional constrained control of elastic cable-driven parallel robots (CDPRs). In CDPRs, the cable tension can only be positive, requiring unidirectional control effort. In the proposed structure, the positive tension distribution (PTD) of the elastic CDPR is ensured using a prevention function. Compared to existing methods for elastic CDPRs, this new technique has significantly lower computation time, which is essential for real-time applications. Moreover, two adaptive observers are utilized to tackle undesirable events, particularly partial failures. The stability analysis of the closed-loop system is provided using Lyapunov’s second method. The simulation study shows that the proposed method improves the tracking accuracy and is significantly faster than conventional methods. The effectiveness of the proposed method is evaluated in the presence of model uncertainties and various faulty conditions.