高超声速飞行器分数阶滑模姿态控制方法研究

发布时间：2018-03-05 22:33

本文选题：分数阶滑模　切入点：姿态控制　出处：《北京理工大学》2016年硕士论文　论文类型：学位论文

【摘要】：高超声速飞行器对其姿态控制器的鲁棒性和控制精度要求,随着飞行器的发展变得越来越高。飞行过程中马赫数高、飞行区域广、通道间耦合作用强、参数摄动以及外部不确定干扰复杂,加大了控制器的设计难度。在滑模控制中加入分数阶微积分,分数阶滑模控制结合了两者的优点,不但使控制系统具有强鲁棒性,而且提高了控制系统的响应特性,是非线性控制的重要组成部分。本文研究了分数阶滑模姿态控制器在高超声速飞行器姿态控制方面的应用。主要研究内容有:基于分数阶特征比整定的思想,首先设计了一种线性分数阶滑模姿态控制器,闭环系统响应能够以设定超调跟踪姿态角指令。该方法将系统响应的超调量和响应速率分开设计,使得飞行器姿态角误差能够以预先设定的2%的超调渐进收敛到0,并且可以通过改变相应时间常数调节闭环系统的响应速率而不改变系统响应的超调量,解决了分数阶滑模面参数给定问题。进一步,提出了一种基于变伪时间常数的非线性分数阶滑模姿态控制器,克服了线性分数阶滑模姿态控制方法中的不足,解决了飞行器姿态控制中存在的加快系统响应速率和控制量饱和之间的矛盾。之后又提出了一种伪时间常数自适应的分数阶滑模姿态控制方法,伪时间常数通过自适应方法获得,加快系统滑模面的收敛速率以缩短系统到达段时间,系统鲁棒性得到了增强。针对传统整数阶PID滑模姿态控制方法中可能出现的积分项过大问题,将其推广到分数阶,在整数阶积分项上引入积分阶次,以设计一种分数阶PID滑模姿态控制方法,削弱了误差积分项,避免系统超调量过大,并且飞行器姿态角误差能够渐进收敛到0。在此基础上设计了一种能够固定时刻收敛的分数阶时变滑模姿态控制方法,飞行器姿态角误差能够在固定时刻收敛到0,并且系统状态全局都在滑动段,鲁棒性得到加强。
[Abstract]:With the development of the aircraft, the robustness and control accuracy of the hypersonic vehicle to its attitude controller become more and more high, the Mach number is high, the flight area is wide, and the coupling between the channels is strong. The complexity of parameter perturbation and external uncertainties makes the design of the controller more difficult. Adding fractional calculus to sliding mode control, fractional sliding mode control combines the advantages of both, which not only makes the control system strong robustness, but also makes the control system more robust. And the response characteristics of the control system are improved, In this paper, the application of fractional sliding mode attitude controller to the attitude control of hypersonic vehicle is studied. The main research contents are as follows: based on the idea of fractional order characteristic ratio tuning, Firstly, a linear fractional sliding mode attitude controller is designed. The closed-loop system response can track the attitude angle instruction by setting overshoot. The overshoot and the response rate of the system response are designed separately. The attitude angle error of the aircraft can converge to 0 with a pre-set overshoot of 2%, and the response rate of the closed-loop system can be adjusted by changing the corresponding time constant without changing the overshoot quantity of the system response. Furthermore, a nonlinear fractional sliding mode attitude controller based on variable pseudo time constant is proposed, which overcomes the shortcomings of linear fractional sliding mode attitude control method. The contradiction between acceleration of system response rate and control saturation in attitude control of aircraft is solved. Then a pseudo-time constant adaptive fractional sliding mode attitude control method is proposed. The pseudo-time constant is obtained by adaptive method, which accelerates the convergence rate of the sliding mode surface of the system so as to shorten the arrival time of the system. The robustness of the system is enhanced. Aiming at the problem that the integral term may be too large in the traditional integer order PID sliding mode attitude control method, the integral order is introduced into the integral term of integral order, and the integral term is extended to fractional order. In order to design a fractional PID sliding mode attitude control method, the error integral term is weakened and the overshoot of the system is avoided. And the attitude angle error of the aircraft can converge gradually to 0. On this basis, a fractional time-varying sliding mode attitude control method is designed, which can converge at a fixed time. The attitude error of the aircraft can converge to 0 at a fixed time, and the overall state of the system is in the sliding section, so the robustness is enhanced.
【学位授予单位】：北京理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：V249.1

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