Sliding Mode Control Optimized with PSO for Precise Trajectory Tracking of a Two-Axis Gimbal

A two-axis gimbal system is designed utilizing two perpendicular single-axis gimbal systems. The optimization objectives for controlling this system are to obtain the optimal rotation paths around the y- and z-axes, with the requirement of covering all lines of sight (LOS). To achieve these objectives, the two control inputs, which are DC motor voltages, are used to adjust the angles of the two axes, which serve as the system’s outputs, efficiently tracking the reference points. In this chapter, a nonlinear, robust approach, a sliding mode controller (SMC), is proposed for precise path tracking for two-axis gimbal movement. The objectives of this system are to minimize the time required to achieve the desired rotation path and to reduce the system’s steady-state error. To optimize performance, the concept of SMC is combined with the particle swarm optimization (PSO) algorithm. In other words, by integrating SMC into the PSO algorithm, the hybrid approach benefits from SMC’s ability to drive system dynamics robustly and rapidly toward desired states while retaining the population-based global search capability of PSO. This approach leads to a more efficient, stable, and disturbance-resistant system in complex problem spaces. Simulation results show that the proposed controller outperforms both the PID and conventional sliding mode controllers when tracking various command signals. Additionally, in the presence of system uncertainty, the optimal sliding mode controller is the most effective for achieving the best performance. This confirms the robustness of this controller in dynamic operating conditions.