Non-singular fast terminal sliding mode control of robotic manipulator with prescribed performance

Abstract Considering the improvement of transient response when tracking the trajectory of the robotic manipulator, a novel prescribed performance non-singular fast terminal sliding mode (PPNFTSM) controller is designed. The method performs the controller design by introducing performance functions with constraint effects, and, at the same time, transforms the trajectory tracking deviation using the hyperbolic tangent function, and a new error performance index function is designed accordingly to solve the dilemma that the prescribed performance control (PPC) depends on the first constrained value of the system; the error obtained from the transformation is then combined with the non-singular fast terminal sliding mode (NFTSM) for controller design. The proof of the stability is established based on Lyapunov functions. The proposed method does not require an initial tracking condition. This is verified by simulation and ensures that the tracking deviation approaches a delimited region near the equilibrium point with a prescribed transient performance and strong robust performance.