Trajectory Tracking Control of Robot Manipulator Using Hybrid Control Strategy

This article proposes a linear−quadratic regulator-based optimal second-order sliding mode controller for trajectory tracking control of robot manipulators under lumped disturbance. The coupled dynamics of the manipulator with a geared motor and the desired joint space trajectory are designed and discussed. The linear−quadratic regulator controller is developed by penalizing corresponding weighting matrices for the nominal input−output linearized robot dynamics. An integral sliding mode control law is incorporated to address external disturbances, ensuring the linear−quadratic regulator's optimized performance remains unaffected. A non-singular terminal sliding mode control law is then cascaded with the optimal integral switching manifold to alleviate chattering effects. The proposed strategy, validated using SimMechanicsTM/Simulink in MATLAB®, demonstrates superior performance compared to known control algorithms by achieving joint trajectories with lower torque and smoother control. The validation of the proposed controller is based solely on simulation and has not been implemented practically. Specifically, the energy consumption and tracking errors of the proposed controller are 27.63 J and 0.00167, respectively.