Observer-based event-triggered sliding mode tracking control for uncertain robotic manipulator systems

In this paper, a sliding mode trajectory tracking control law based on a state observer and an improved event-triggered strategy is designed to control the uncertain manipulator with disturbance. First, the state observer is adopted to solve the control problem when the velocity trajectory is unpredictable. In contrast with the time-triggered approach, an improved event-triggered rule is designed to reduce the number of control updates and save communication resources. To reveal the advantages brought by the event-triggering mechanism, a new formula is designed to calculate the communication resource savings rate. Then, a sufficient condition is derived by using Lyapunov analysis to ensure the stability of error dynamics. Finally, a two-link robotic manipulator example is used to prove the effectiveness of the proposed method. The simulation shows that the controller reduces the frequency of control signal updates while ensuring system performance.