Rendezvous And Docking Control With Prescribed Performance Theory

As one of the most important key technologies in China’s aerospace technology,spacecraft rendezvous technology has been widely used in many missions such as the construction of the International Space Station,on-orbit service,and air defense.Therefore,the design of the controller becomes the prerequisite for the successful execution of the task is also very important.For the design of attitude control system,the following issues should be paid attention to: The first is robustness.From the perspective of safety,the controller is required to have the ability to deal with disturbances and uncertainties caused by bad space environments.At the same time,there are constraints on the dynamic and stable characteristics of spacecraft in practical engineering.And because some missions still have time window conditions,and the asymptotic steady-state and finite-time stabilization technologies no longer meet the actual needs,the spacecraft has reached a steady state at a given moment.Therefore,this article will take the spacecraft rendezvous and docking maneuvers as the background and adopt the backstepping control theory to study the preset performance control of unknown system parameters and the presence of external interference,and further innovatively propose a preset time stability control method.The main research contents of the thesis are as follows:First,the basic mathematical principles of backstepping and the design ideas of the preset performance controller are given,and the system stability analysis method based on Lyapunov theory is discussed.Then,the relative motion attitude orbital kinematics model and dynamics model of the spacecraft were established respectively.Then,the issue of relative motion control is deeply studied.First,according to the spacecraft’s transient characteristics and steady-state performance constraints,the most basic preset performance limitation method is given;then,when the upper bound of external interference is unknown and the parameter uncertainty is considered,backstepping can be used The method combines the neural network design with the minimum parameter learning method to design an improved adaptive preset performance control method.Because the introduction of neural network can effectively solve the influence of uncertainty,the minimum parameter learning method can replace the weight matrix of the neural network with a parameter,which greatly simplifies the computational complexity of the controller.Finally,the Lyapunov theory can be used to prove the asymptotic stability of the two systems,and the effectiveness of the basic control scheme and the improved control scheme is proved by simulation.Then,aiming at the spacecraft missions with specific time window requirements,the control method of preset time enhancement preset performance is studied.This paper innovatively proposes a design method for the performance function of the preset time,and based on the designed performance function,in the case that the unknown spacecraft inertial parameters and the upper bound of external interference cannot be accurately known,it achieves both transient and steady-state performance.Adaptive control.Compared with the existing finite-time attitude control method,the method proposed in this paper does not use the state fractional order and symbol technology,so it is more concise and easy to implement online.This part of the research work develops the infinite time(exponential convergence)stable preset performance controller design to the appointed time preset performance controller design.Finally,the overall work is summarized,and the direction of further research in the future is made relevant prospects.