The Small Satellite Adaptive Sliding Mode Attitude Controller with Mechanical Flywheels Disturbance Compensation

An adaptive sliding mode control law with disturbance compensation is proposed for small satellite attitude control system to overcome the deterioration of performance under mechanical flywheel disturbance.According to the small 3-axis stabilization satellite attitude control system with mechanical flywheels as actuators,the dynamic model of the system is firstly given,including attitude dynamic equations of a satellite with mechanical flywheels and the mechanical flywheels control system model.Secondly,an adaptive sliding mode control law which takes wheel disturbances into account is given and state observer is used to estimate wheels friction disturbance for compensation.The stability of the system is proven by using Lyapunov theorem.Finally,the simulation results show that this method shortens flywheel speed zero-crossing time,decreases the largest attitude disturbance value and effectively improves attitude control accuracy and stability.