Input saturation control of manipulator based on fully actuated system approach

A control strategy based on fully actuated system approach is proposed for the manipulator system with input saturation. By introducing a smooth hyperbolic tangent function to approximate the saturation function, the original system is transformed into a smooth system. The complex differential operation is converted into algebraic operation by introducing a first-order low-pass filter. By designing an adaptive law, the uncertainty of the system model is effectively estimated. Based on fully actuated system approach, the controller for the manipulator system is directly designed, which eliminates the step of converting the original second-order strict feedback system into a first-order strict feedback system, reduces the steps of controller design, lowers the complexity of algorithm design, and effectively avoids the "differential explosion"problem. The Lyapunov stability theory is used to prove that all signals in the closed-loop system are uniformly ultimately bounded. Finally, numerical simulations of the manipulator system are performed to verify the effectiveness of the proposed method.