Robust Tracking Under Nonlinear Friction Using Time-Delay Control With Internal Model

In this paper, the robustness problem in time-delay control (TDC) is considered in the presence of the nonlinear friction dynamics of robot manipulators. As a remedy for this problem, the TDC is enhanced with a compensator based on internal model control (IMC). The robustness and stability of the proposed method have been analyzed to be effective against friction while preserving the positive attributes of the TDC: It is simple, efficient, and easily applicable because it does not require a complete plant model. Through experiments, the proposed method achieves accuracy levels that are 10-20 times better than that of the TDC, thereby confirming its effectiveness under friction.