Performance Constraint Control For Spacecraft Attitude

Facing the country’s efforts to build space power and the demand for emerging aerospace technologies,large-scale space construction and on-orbit services have rapidly developed.For the emerging and increasingly complex spacecraft control tasks,the control methods need to consider more constraints and higher performance requirements caused by the close rendezvous of the spacecraft.Traditional control methods mainly focus on the stability of the closed-loop system,and lack strict constraints on the performance of the closed-loop system.The way of optimizing control performance through parameter adjustment will also increase the workload.Thus,the traditional control methods are slightly weak in such tasks.Inspired by the idea of constraining the performance of the closed-loop system in advance,the concept of performance constraint control came into being.The performance constraint control is designed so that the closed-loop system can theoretically meet the pre-defined or prescribed performance requirements and simplify parameter selection.This dissertation is dedicated to solving the expected transient and steady-state constraints and precise control problems of the spacecraft attitude tracking through the performance constraint method.That is,the relevant expected parameters of the time-domain performance response of the spacecraft attitude closed-loop system,such as settling time,overshoot,and steady-state error,are abstracted as performance constraints.According to constraint conditions,considering external disturbances,input constraints,optimal state and energy consumption,various related control methods are proposed to achieve the precise control objectives of the system under constraint conditions and various complex situations.Specifically:For the precise control problem of the spacecraft attitude tracking,considering the expected performance constraints,this dissertation proposes the time-varying continuous performance constraint function that explicitly contains the maximum settling time parameter and the error transformation method.By using this function to construct the constraint conditions with the error transformation method,the maximum settling time and the upper bound of the steady-state error when the maximum settling time is reached can be artificially set according to the actual task requirements.Based on the proposed performance constraint function and the error transformation method,this dissertation proposes the spacecraft attitude tracking performance constraint control methods with pre-defined time parameters,including attitude performance constraint asymptotic control,attitude performance constraint finite-time control,and its robust result,the improved transient performance constraint control based on the norm-normalized sign function and ratio persistence property,and its robust result.These methods can ensure that the settling time,overshoot,and steady-state error of the closed-loop system state are less than their corresponding pre-defined values.In addition,the finite-time results and the norm-normalized sign function further improve the transient performance of the closed-loop system.Simultaneously,considering the external disturbances,the observers enhance the robustness of the closed-loop system.For the problem of control input constraints in performance constrained control with pre-defined time parameters,this dissertation designs the spacecraft attitude asymptotic control based on the command filter backstepping method as a basic method.Then,the related attitude tracking performance constraint control methods with pre-defined time parameters based on the command filter technique are proposed,including the spacecraft attitude performance constraint asymptotic control based on the command filter technique and the spacecraft attitude performance constraint finite-time control based on the command filter technique.Considering the difference between the command signals before and after filtering and the stability of the closed-loop system containing the filters,this dissertation proposes the asymptotically stable or finite-time stable compensators considering performance constraints to compensate for the signal loss caused by filtering.These methods fully consider the adaptability of the spacecraft actuators to the control commands.Through the command filter technique,the theoretical control signal is actively adjusted so that the control input signal of the actual system has the appropriate amplitude,rate,and bandwidth,etc.Considering the external disturbances,this dissertation analyzes or proposes the robustness correction results of the corresponding controls.For the optimization problem of the spacecraft-related-state and energy consumption in performance constraint control with pre-defined time parameters,this dissertation proposes related optimal control methods for spacecraft attitude tracking performance constraints with pre-defined time parameters based on adaptive dynamic programming,including spacecraft attitude performance constraint optimal control based on adaptive dynamic programming,spacecraft attitude performance constraint optimal control based on experience replay adaptive dynamic programming,and spacecraft attitude performance constraint control with N-actuators based on the non-zero-sum game.The above control methods fully consider performance constraints and optimal control issues.In the framework of the spacecraft attitude performance constraint control,the quadratic value function of the related state and control input is defined.Then,through the adaptive dynamic programming method,the online-adaptive neural network is used to estimate the solution of the Hamilton-Jacobi-Bellman(HJB)or the coupled Hamilton-Jacobi(HJ)equations.When the residual errors of the HJB equation or the coupled HJ equation converge to 0,the optimal controls are obtained to solve the optimal control problem under performance constraints with pre-defined time parameters.The dissertation carried out rigorous stability analysis and comparative simulation analysis on the proposed performance constraint control methods,which verified the rationality and effectiveness of the proposed control methods.The proposed control methods emphasize performance guarantees by considering a variety of actual engineering conditions.They are suitable for attitude control situations with actual physical constraints or virtual control constraints.They provide a theoretical basis and simulation experience for the motherland to develop high-performance,high-precision spacecraft attitude control.It hopes these will contribute to the development of the motherland’s aerospace technology.