Research On Iterative Learning Control Of Small Body Spacecraft Trajectory Tracking

In order to obtain the accurate prior information for the small body spacecraft,it is necessary to ensure the high-precision trajectory tracking control.In the flight orbit,the spacecraft will be affected by various unknown periodic and non-periodic disturbances,such as sunlight pressure and non-spherical gravity,in the complex outer deep space environment,which makes the orbit tracking control of the small-body spacecraft have the characteristics of multi-source disturbances,unknown dynamic environment and multiple constraints.Small bodies,this paper spacecrafts the strong nonlinear,strong coupling and deep space is irregular the gravitational field and spatial perturbation action leads to poor trajectory tracking control accuracy and robustness and response speed slow problem,based on the operation characteristics of periodic orbit period,using the data from the orbiting in deep space spacecraft orbit trajectory tracking control method of the research.Details are as follows:（1）To solve the problem that the tracking control robustness of the small body detector is seriously affected by the uncertainties of deep space environment,the perturbation of measurement parameters and the system’s own parameters,a sliding mode tracking control method based on adaptive control law and dynamic surface technology was designed.The proposed method is based on nonlinear disturbance observer,and the traditional sliding mode control method is optimized by introducing dynamic surface technology and hyperbolic tangent function,and constructing adaptive law to estimate the upper bound of disturbance.Finally,the convergence proof and simulation analysis verify the effectiveness of the proposed method..（2）An active disturbance rejection control method based on iterative learning control was proposed to solve the problem that the trajectory tracking control accuracy was affected by periodic disturbances,mainly non-spherical gravitational perturbation,in the flight orbit of a small body detector.It firstly estimates the system disturbance observer is designed by the total disturbance,considering active immunity control can improve the response speed.The disturbance estimation of the observer is used to design the control law to realize the active compensation of the total disturbance.The convergence proof and simulation analysis prove that the proposed method can not only accelerate the response speed,but also improve the accuracy of the trajectory tracking control.（3）To solve the problem that the probe will be affected by periodic and aperiodic disturbances simultaneously during repeated orbit,an iterative learning tracking control method for the orbit trajectory of the small object probe combined with sliding mode control was proposed.The iterative learning controller is designed to eliminate the influence of non-spherical gravitational perturbation and the sliding mode feedback controller is designed to eliminate the influence of its own parameters perturbation.The controller can not only improve the control accuracy and speed up the response,but also has good robustness.