Torque mapping in C : Accelerator pedal vs speed

[yanno_yokizo]

Hi guys, I am struggling trying to define an interpolation based on the below accelerator pedal map. The target is to define a calculation method that outputs the Torque function of the Pedal angle and the current vehicle speed. I am working on the software implementation of this system in C.

Thanks for your tips

 

[shortbus=]

Might be wrong, but think your forgetting a very important thing in doing this. That thing is the road and environment. A hill or even a head or tail wind on the vehicle puts more into this than you are showing. Unless your not doing this for an actual driving vehicle.

 

[rjenkinsgb]

In its simplest form, and assuming linear change of torque with speed between the two lines & no outside influences:


t = b(p) + ((((r(p) - b(p)) / 50) * s);

t is result
b(p) is blue line value for the pedal position
r(p) is the red line value for the pedal position
s is speed.

The difference between the two lines at a given pedal position, divided by 50 to get 1km/h units, multiplied by the speed and added to the blue line value.

(Assuming I've not mistyped anything!).

Real-world applications typically use multi-dimensional lookup tables for this type of thing, with rather more inputs.

 

[danadak]

Two methods :

1) Least squares error fit

Least Squares Fitting: How to Fit a Curve to Data | Aleksandr Hovhannisyan

A review of the theory behind the least squares method, as well as a look at how to perform straight-line and polynomial least squares fitting, both by hand and with Python.

www.aleksandrhovhannisyan.com

2) Power series error fit (better for non linear)

Overview of Curve Fitting Models and Methods in LabVIEW

This document describes the different curve fitting models, methods, and the LabVIEW VIs you can use to perform curve fitting.

www.ni.com

Regards, Dana.

 

[yanno_yokizo]

In its simplest form, and assuming linear change of torque with speed between the two lines & no outside influences:


t = b(p) + ((((r(p) - b(p)) / 50) * s);

t is result
b(p) is blue line value for the pedal position
r(p) is the red line value for the pedal position
s is speed.

The difference between the two lines at a given pedal position, divided by 50 to get 1km/h units, multiplied by the speed and added to the blue line value.

(Assuming I've not mistyped anything!).

Real-world applications typically use multi-dimensional lookup tables for this type of thing, with rather more inputs.

Thanks. Easy to implement and works beautifully