汽车matlab模型

1、Chapter 5 Vehicle Modeling in Matlab 施树明 Contents nModeling a Cruise Control System nModeling a Cruise Control System in Simulink nModeling a Bus Suspension System using Transfer Functions nBus Suspension Modeling in Simulink Modeling a Cruise Control System Using Newtons law, modeling equations for

2、 this 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 nRise time 5 sec nOvershoot 10% nSteady state error 2% nTo solve th

3、is problem using MATLAB, copy the following commands into an new m-file: qm=1000; b=50; u=500; qnum=1; den=m b; qcruise=tf(num,den); MATLAB representation 1. Transfer Function Modeling a Cruise Control System nOpen-loop response step(u*cruise) n2. State-Space nWe can rewrite the first- order modelin

4、g equation (1) as the state-space model. nTo 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); DuCxy BuAxx MATLAB representation Modeling a Cruise Control System nOpen-loop response

5、 step(u*cruise) Modeling a Cruise Control System in Simulink Using Newtons law, modeling equations for this system becomes: (1) Modeling a Cruise Control System in Simulink nBuilding the Model nOpen-loop response 思考题 n本节建立的汽车动力学模型有何问题？ n如何改进？ n请课后重新建模并编程分析。 Modeling a Bus Suspension System using Tra

6、nsfer Functions * body mass (m1) = 2500 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.

7、 * road disturbance (W) * control force (u) = force from the controller we are going to design. Modeling a Bus Suspension System using Transfer Functions nPhysical setup nDesign requirements nEquations of motion nTransfer function equation nEntering equations into MATLAB nOpen-loop response Bus Suspension Modeling in Simulink nPhysical setup nBuilding the model nOpen-loop response a1 v1 x1 a2v2 x2 W U Sum5 Sum4 Sum3 Sum2 Sum1 Sum Spring 2 k2 Spring 1 k1 Scope Mass 2 -K- Mass 1 -K- Integrator 3 1 s Integrator 2 1 s Integrator 1 1 s Integrator 1 s Derivative