Attitude Fault Tolerant Control Of Spacecraft Based On High Order Sliding Mode And Artificial Potential Function

Along with the development of space,space missions,structure and function also increasingly complex spacecraft,the spacecraft payload attachment types increasingly rich,then improve degree of automation,equipment such as space flexible manipulator,large antenna,solar panels and other large flexible attachment of on-orbit spacecraft is more and more,the complexity of the system is also more and more high.In the complex space environment,the complex spacecraft system sensor and actuator failure probability is becoming more and more big,once the on-orbit stage fails,whether adopt the on-orbit servicing technology or give up the partial function of spacecraft,a high price needs to pay,while the fault-tolerant control can solve the problem to a great extent.This paper takes flexible spacecraft as the research object,comprehensively considers the flexible interference and common faults of spacecraft,and studies the fault-tolerant control of flexible spacecraft based on the adaptive sliding mode control theory.The main research contents are as follows:First consider described in attitude quaternion kinematics equation of spacecraft,the modal method is given directly based on the assumption of flexible spacecraft dynamic equation,and the flexible mode carries on the preliminary analysis and interference,at the same time for actuator fault types and made a brief analysis of the mathematical model,and introduce the basic knowledge of sliding mode control theory.Secondly,the fault tolerant control problem of multiplicative failure of actuator is considered.Firstly,the fault element is directly adaptive estimated,and the fault tolerant controller is designed based on the general linear sliding mode surface.Considering the limitation of control input,the adaptive sliding mode surface is used to design the controller to meet the input saturation requirement,and the design of the adaptive sliding mode controller is completed by combining the inverse compensation strategy,and the fault-tolerant control of multiplicative fault is realized.Then consider cases indirect estimation of unknown fault elements,the output of the second-order sliding mode controllers,smooth,based on the fault element separation and flexible interference to synthetically estimate,combined with the control system model and Lyapunov stability theory to complete the design of adaptive sliding mode fault tolerant controller,and implements the limited time of fault-tolerant control.At last,a new adaptive law which does not depend on the model and Lyapunov stability principle is redesigned by using the characteristics of potential function,which is used to update the gain coefficient of sliding mode controller.Based on this,an adaptive sliding mode controller is designed to realize fault-tolerant control of actuator faults of flexible spacecraft,reduce the influence of actuator faults on attitude maneuver control,and fully weaken the chattering inherent in the sliding mode controller when the control system is stable,and have good robustness to external uncertainties.