Adaptive Dynamic Surface Sliding Mode Control for Orbit Tracking of Small Celestial Body Detector with Disturbance Observer

Abstract

In order to solve the problem of tracking the orbit of small celestial body detector under the disturbance of unknown external environment, a dynamic model of the orbit of small celestial body detector with unknown disturbance was established. The perturbation observer method was utilized to estimate the disturbance to the external environment of the small celestial body detector, and its dynamic characteristics were observed and compensated by the controller, so that the sliding mode shake amplitude could be reduced. An adaptive law was designed to estimate the bound of disturbance observation error, and the symbol function was replaced by hyperbolic tangent function, thus the buffeting was further eliminated and the control accuracy was improved. At the same time, dynamic surface technology was introduced to solve the differential explosion problem caused by the derivative of virtual control. At the end of the paper, a small object 243Ida was utilized as the target object for simulation verification. In the simulation results, the detector is able to track the desired trajectory and the position and velocity errors are significantly reduced at the time of 70s, and the controller output is smooth. The results show that the proposed method is an effective and reasonable method for the orbit tracking of celestial body detectors.