Building a Simple Drivetrain Model in Simulink

This tutorial will demonstrate how to model the drive force of a vehicle's tires and to calculate the vehicle's velocity and position from the drive force. It will have "gear" as an input, and drive force (lbf) as an output. The first section of the tutorial is found in F-5 of "Simulink for Automotive System Design." F_drive = (GearRatio*FDR*AVgEngTorque*Loss)/r_tire The gear ratio is determined by the gear the transmission is in. FDR (final drive ratio) represents the differential's gear reduction. Loss represents the efficiency of the drive train. Drivetrain loss occurs due to friction in the drivetrain components. The second subsystem created will be analyzing the velocity and position of the car. The output of the previous subsystem is force. Force equals mass times acceleration. Force is coming from the previous subsystem with the unit, lbf. To convert from lbf to lbm*ft/s^2, force will be divided by 32. d^2(x)/d(t^2)=Fdrive/(32*m) This equation will be integrated once to solve for the velocity (ft/s) of the car. To solve for the position (ft) of the car, the equation will be integrated twice. The car weighs 3000 lb, starts out at a velocity of 5 ft/s, and has an initial position of 100 ft.