New robust control strategy for module manipulators via sliding mode control with an extended state observer

This paper proposes a robust control strategy for module manipulators based on sliding mode control (SMC) and an extended state observer (ESO). First, the nth-order system function is reduced into a first-order function whose argument is the sliding mode. Based on the generalized system, the structured and/or unstructured system non-linear uncertainties are lumped together to form a gross uncertainty which can be estimated by the ESO as an extended state in real time. Then, a controller of the generalized system is designed using SMC based on the extended state. The stability of the system is strictly analysed via the Lyapunov stability theorem approach. This method is applied to the control problem for robot manipulators. Trajectory tracking problems of the joints in a PowerCube robot manipulator are investigated with simulations to validate the analysis.