Robust Nonlinear Control of Laser Scanning System under Stochastic Mechanical Disturbances

This paper presents a robust nonlinear control strategy for a laser scanner’s actuator operating under stochastic mechanical disturbances. External perturbations are represented as bounded stochastic torque inputs, capturing the aggregate effect of structural imbalance, impacts, or system degradation. Experimental observations of vibration-induced angular fluctuations motivate this modeling choice, highlighting the need for control strategies tolerant to bounded stochastic disturbances resulting from unpredictable mechanical faults. A smooth hyperbolic-based control law is proposed to achieve robust velocity tracking under these uncertain conditions. Global asymptotic stability is formally established through Lyapunov analysis, and simulation results confirm that the proposed method effectively maintains convergence and bounded control effort in the presence of estimated disturbance torque. The formulation is suitable for fault-tolerant control of precision actuators where physical irregularities are difficult to isolate or diagnose in real time.