Design Of Motion Control System For Underactuated Aerostat Based On Sliding Mode Active Disturbance Rejection

This article concerns the control problems presented in the tracking of the fin-less underactuated euler aerostat driven by two propellers with actuators saturation,the uncertain parts of the system and wind disturbance taken into concern.The main works of this paper are listed below:1.Nonlinear model of underactuated aerostat was established: the six degree of freedom model and three degree of freedom model were built to study the kinetic and dynamic characteristics of the underactuated aerostat.The simulation platform was built in Matlab/Simulink environment.2.Sliding model active disturbance rejection control was proposed for motion control of underactuated aerostat: The active disturbance rejection control(ADRC)and sliding model control(SMC)were combined.The functions of the tracking differentiator and the characteristics of the extended state observer in the active disturbance rejection control were introduced with simulation experiments;the SMC was used as part of the feedback error control law.Such the sliding mode active disturbance rejection control method was proposed to improve the robustness of the controller.The chattering problem caused by SMC was considered.The effectiveness and robustness of the sliding mode adaptive disturbance rejection control were verified by simulation results.3.Plane trajectory tracking control of underactuated aerostat was realized: The controller was divided into inner and outer loop control loop controller,the outer loop was designed and the differential signal extraction were resulting in a virtual track.The inner loop was designed with virtual trajectory as the target value.The sliding surface was designed according to the forward flight velocity error and the lateral velocity error respectively.In order to improve the system’s ability in suppressing disturbances and reducing upper bound of disturbance,adaptive sliding mode variable structure control was established and the disturbance was compensated.Finally,the model was simulated by the aeronautical device designed by Shanghai Jao Tong University,and the robustness and effectiveness of the controller with condition of wind disturbance.4.Space path following control of underactuated aerostat was accomplished: The state control of forward,lateral,yaw and roll were studied based on the 6-DOF aerostat system.The navigation algorithm was designed in the Serret-Frenet coordinate,the proposed path was designed as the function of the attitude and position.The design of yaw angle control and roll angle control were designed separately by using the longitudinal velocity and lateral velocity coupling design of slide mode active disturbance rejection control law.The simulation experiment was carried out to verify the design theory.