Adaptive Sliding Mode Control for Spacecraft Rendezvous With Unknown System Parameters and Input Saturation

Zongling Li,Shuo Song,Qingjun Zhang,Ganxin Yu,Hongtao Cui

doi:10.1109/access.2021.3075564

Abstract

In this study, we investigated the sliding mode control (SMC) for the spacecraft rendezvous maneuver under unknown system parameters and input saturations. On the basis of the attitude and position tracking subsystem, two anti-saturation sliding mode surfaces (SMSs) are constructed to guarantee the exponential convergence of tracking errors between the target spacecraft and the pursuer spacecraft. In connection with hyperbolic tangent, a modified auxiliary system is established to compensate the nonlinear constraint caused by the actuator saturation. Meanwhile, in order to enhance the practicability and reliability of the controller, unknown inertial information is taken into consideration. The resulting system uncertainties are estimated accurately via adaptive laws. Additionally, it is concluded that the designed controller is capable of ensuring the boundedness of the closed-loop signals with reasonable selection of control parameters. Finally, the effectiveness and advantages of the proposed methods are verified through numerical simulations.

Highlights

In the last several decades, the rendezvous maneuver control of spacecraft has been widely applied in space missions such as construction of orbiting space stations, docking and removing space debris, among others
Compared with the existing control schemes of spacecraft rendezvous maneuver [7], [11], [25], the time-varying inertial parameters are considered in this paper, and the resulting unavailable dynamics are estimated by the design of adaptive update laws
This paper focuses on the trajectory tracking control for the spacecraft rendezvous maneuver suffering from input saturation and system parameter uncertainties

Summary

INTRODUCTION

In the last several decades, the rendezvous maneuver control of spacecraft has been widely applied in space missions such as construction of orbiting space stations, docking and removing space debris, among others. Inertial parameters are not always measured definitely for designers during practical missions, for which actions like fuel consumption, rendezvous and docking between space vehicles, load and shape adjustments, will change the inertial information of in-orbit spacecrafts [18]–[20] Given this fact, with no exact knowledge for the mass and inertial matrix of control object, an extended state observer is designed in [18] to estimate the relative parameters in real-time. Compared with the existing control schemes of spacecraft rendezvous maneuver [7], [11], [25], the time-varying inertial parameters are considered in this paper, and the resulting unavailable dynamics are estimated by the design of adaptive update laws. More details on the modeling of attitude dynamics can be found in Ref. [1]

RELATIVE ORBIT DYNAMICS MODEL

CONTROL OBJECTIVE

SIMULATION RESULTS

CONCLUSION