A Controller For Small-scale Unmanned Helicopter Under Wind Disturbance Based On Output Regulation

Small-scale unmanned helicopters have several advantages such as small size,sensitive,able to take off without a runway,can be independent hovering,etc.They are widely used in both military and civil scenes.However,when unmanned helicopters are used in complex outdoor environments,such as outdoor aerial photography,mapping,and agricultural irrigation,it is inevitably to face the problem of wind disturbances.Therefore,the design of the unmanned helicopter with winddisturbance controller is one of the most urgent problems to be solved.The most commonly used wind-disturbance controller is based on the back-stepping method and state observer compensates,and its accuracy depends on the accuracy of the state observer.The traditional output regulation theory can reject the disturbance while tracking the reference input.It is suitable for the wind-resistant controller,but it is complicated in design procedure and the control effect still has possibility to be improved.In order to solve these problems,this dissertation presents a new type of output regulation control strategy for unmanned helicopter wind-resistant control.In this dissertation,wind disturbance is modeled using wind tunnel laboratory data by the system identification method to describe the wind disturbance,and the wind/torque disturbance was quantitatively calculated by the wind speed.Then,based on this,the wind influence function is optimized.The optimized wind influence function has less parameters and the identification results show that the correlation between real data and fitted data exceeds 96% under different wind directions and wind velocities,which means that the estimated force/torque by wind influence function can well match the real force/torque in different wind directions and speeds.This provides the foundation for the next controller design.When designing the controller,a new type of output regulation is proposed for all lower triangle models to reduce design complexity and improve control effect.Combining this control strategy and the wind influence function,the winddisturbance controller under different wind directions and wind speeds is designed.At the same time,for the convenience of control,the UAH system is divided into two lower triangular subsystems of position and attitude angle.The wind-disturbance controllers are designed respectively for the both two subsystems,so that the UAH can reach the required position and the required heading angle under wind disturbance.In order to verify the control algorithm,the traditional output regulation,the backstepping method with the state observer and the lower triangular regulation proposed in this dissertation are simulated and compared in MATLAB.The simulation results show that,compared with the traditional output regulator and the back-stepping method with the state observer,our proposed lower triangular output regulator requires fewer parameters,is easier to adjust parameters,and can control the unmanned helicopter arriving at the designed position and heading angle under wind disturbance within a specified time.At the same time,the overshoot is smaller and the setting time is shorter.