摘要:球杆系统是控制领域一个典型的非线性不稳定系统,其控制目的是将小球随时定位在导轨的指定位置上。本课题将球杆系统的数学模型分解为机械部分数学模型、角度关系模型、电机模型,联合得到球杆系统的非线性模型,并在平衡点附近对球杆系统进行线性化处理,得到球杆系统在平衡点的线性模型。课题通过分析球杆系统的开环阶跃响应,得出系统本身的不稳定性,从而针对球杆系统设计了两种控制器,分别为基于频率响应的控制器和二次最优控制器,以控制小球位置的平衡。课题采用超前校正设计频率响应控制器,并实现了基于频率响应的球杆位置的实时控制;针对球杆系统的不稳定和非线性特点,运用二次型最优控制理论进行反馈控制规律的研究,选取小球位置,小球速度、大齿轮角度和大齿轮角速度作为状态变量,设计了基于LQR的球杆系统控制器,在MATLAB和Simulink环境进行仿真,对比分析了两种控制器的控制效果。4570
关键字:球杆系统;数学模型;频率响应;二次最优控制
Research and design of ball and beam system’s control method
Abstract: Ball-beam system is a typically nonlinear and unstable system in the field of control; what the objective of the control is to locate the ball at the given position of the guide rail. By building the models of machines, the relationship of angles and the model of motor, the nonlinear model of the ball-beam system can be obtained. Linearizing the ball-beam system near the equilibrium point contributes to getting the ball-beam system’s linear model. The purposes of this paper are to analyze the response of its open-loop step input and design two controllers. One is based on frequency response and the other is based on the quadratic optimal control. Frequency response controller which uses the lead compensation can successfully implement the real-time control. In allusion to the instability and non-linear characteristics of the ball-beam system, we use the theory of quadratic, with selecting the location of the ball, the speed of the ball, the gear's angle and gear's angular velocity as the state variable, to design the controller based on LQR. Meanwhile I conduct the simulated experiments using MATLAB and make contrastive analysis from the control effects of two controllers.
Keywords: Ball-beam system;Mathematical model; Frequency response;Quadratic optimal control