摘要
对于具有严重非线性、多变量以及参数不确定等特点的高超声速飞行器的轨迹控制系统,滑模控制是一种十分有效的控制方法,但传统的滑模控制会不可避免的产生抖振现象,为了彻底消除这一现象,设计了一种新型的自适应全阶终端无抖振滑模控制律。首先,简要介绍了高超声速飞行器纵向非线性模型,并给出反馈线性化后速度和高度的状态方程。其次,假设所有状态可测,采用全阶终端滑模滑动流型,分别对速度和高度两个子系统设计有限时间收敛的全阶终端滑模控制器,以避免奇异问题,并引入一阶低通滤波器作用于控制输入,以消除由开关函数引起的抖振现象;最后,采用扩张状态观测器对不可测状态进行估计,设计了自适应全阶终端滑模控制律。数字仿真表明,自适应全阶滑模控制器能够使系统在有限时间内跟踪到给定指令,并彻底消除了抖振现象。仿真验证了所提出控制律的有效性。
Sliding mode control theory is a quite efficient way to deal with the control problem of hypersonic vehicles trajectory tracking system which is nonlinear, multivariable and with uncertain parameters. However, the general Sliding mode control theory can introduce chatting inevitably. To eliminate the chatting, a new adaptive full order terminal sliding mode chatting free controller was designed. First, the nonlinear longitudinal model of hypersonic vehicles and the state - space equations of velocity and height in the feedback linearization form were presented. Secondly, assuming all states were measurable, terminal sliding mode controllers convergencing in finite time were designed for speed and height subsystems respectively, choosing full - older mainfold to avoid singularity. And a first - order low - pass filter was introduced in the control input to eliminate chattering. Then the extended state observers were adopted to estimate the unpredictable states. Finally, the estimated states were used for contorl. Digital simulation shows that the extended state observers can achieve estimations with relatively high precision and the sliding mode controller with the real states can make the systems track to the given instructions in finite time with chattering phenomenon being eliminated. The simulation verifies the validity of the proposed control law.
作者
李雅君
侯明善
梁帅
刘柏均
LI Ya - jun, HOU Ming - shan, LIANG Shuai, LIU Bai - jun(College of Automation, Northwestern Polytechnical University, Xi＇an Shanxi 710129, China)
出处
《计算机仿真》
北大核心
2018年第10期72-77,共6页
Computer Simulation
