In this paper, we investigate and employ a torque redistribution approach to track a preplanned trajectory while avoiding actuator saturation for redundantly actuated, parallel robots encountering actuator failure. The redistribution criterion proposed and utilized in this work minimizes class 1 discontinuities in the actuator torque profiles (i.e., torque corner effects) and keeps the new torque requirements of the remaining actuators “close” to their original saturation-free requirements while still tracking the planned end-effector trajectory. The computed torque method is employed consisting of a model reference algorithm in the feedforward process, and a PID controller in the feedback process. The results of simulations encountering both full and partial actuation failure show the viability of this approach to trajectory tracking with redundantly actuated robots in the presence of actuator failure.

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