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1、Chapter 5 Vehicle Modeling in Matlab,施树明 ,Contents,Modeling a Cruise Control System Modeling a Cruise Control System in Simulink Modeling a Bus Suspension System using Transfer Functions Bus Suspension Modeling in Simulink,Modeling a Cruise Control System,Using Newtons law, modeling equations for th
2、is system becomes:,Physical setup and system equations Assumption: 1. the inertia of the wheels is neglected, 2. friction (which is proportional to the cars speed) is what is opposing the motion of the car,(1),Design requirements,Rise time 5 sec Overshoot 10% Steady state error 2%,To solve this prob
3、lem using MATLAB, copy the following commands into an new m-file: m=1000; b=50; u=500; num=1; den=m b; cruise=tf(num,den);,MATLAB representation 1. Transfer Function,Modeling a Cruise Control System,Open-loop responsestep(u*cruise),2. State-Space We can rewrite the first-order modeling equation (1)
4、as the state-space model.To use MATLAB to solve this problem, create an new m-file and copy the following commands: m = 1000; b = 50; u = 500; A = -b/m; B = 1/m; C = 1; D = 0; cruise=ss(A,B,C,D);,MATLAB representation,Modeling a Cruise Control System,Open-loop responsestep(u*cruise),Modeling a Cruis
5、e Control System in Simulink,Using Newtons law, modeling equations for this system becomes:,(1),Modeling a Cruise Control System in Simulink,Building the ModelOpen-loop response,思考题,本节建立的汽车动力学模型有何问题？ 如何改进？ 请课后重新建模并编程分析。,Modeling a Bus Suspension System using Transfer Functions,* body mass (m1) = 250
6、0 kg, * suspension mass (m2) = 320 kg, * spring constant of suspension system(k1) = 80,000 N/m, * spring constant of wheel and tire(k2) = 500,000 N/m, * damping constant of suspension system(b1) = 350 Ns/m. * damping constant of wheel and tire(b2) = 15,020 Ns/m. * road disturbance (W) * control forc
7、e (u) = force from the controller we are going to design.,Modeling a Bus Suspension System using Transfer Functions,Physical setup Design requirements Equations of motion Transfer function equation Entering equations into MATLAB Open-loop response,Bus Suspension Modeling in Simulink,Physical setup Building the model Open-loop response,课堂练习,学生课堂动手建立悬架系统Simulink模型。 上机操作,大作业,思考巡航系统模型存在的问题，构建更加真实的汽车巡航系统模型 仿真分析随机路面激励下的悬架性能,End,
