# Car transfer function (from accelerator to wheels)

by Ulysees
Tags: accelerator, function, transfer, wheels
 P: 341 To be able to write a transfer function which I assume from the pedal angle to the speed of the car, you need to have a linear model which is very likely that it is not possible in this case, and you have to model the disturbances and uncertainties probably in a robust control framework. Of course it depends on what you would like to control, if the dynamics can be approximated by a linear model, then you might compute the impulse response (releasing the pedal suddenly from full throttle). The combustion dynamics can be neglected by some delay for example or a low pass filter. Let say a nicely damped $$\frac{\alpha\omega^2}{s^2 + 2\omega s + \omega^2}$$ where alpha is the gain of the system as in unit angle in the pedal causes alpha times the resulting speed etc. I am quite positive that you can come up with a simple transfer function but it still would be a rough approximation. If you know what you are modeling you can easily come up with your own chip tuning scheme that let say the controller tries to maximize the torque, where it is usually considered to be rocket science by the car magazines. But then you need to do an identification of the particular car that you are interested. Usually, industrial controllers use a look up table of the given torque-power-speed charts and simple PID control schemes. Here is the very basic usage of it http://www.engin.umich.edu/group/ctm...ise/ccPID.html