# How is tractive force calculated from the PID controller of the Glider Model?

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Mathew Lindley on 16 Oct 2017
Commented: DEEPA ANAND on 27 Mar 2019
Hi there,
I am looking at using the model provided in Vehicle Modelling Part 1 in order to model the energy consumption and state of charge of a battery during the endurance event. I am wondering how the tractive force parameter is calculated from the PID controller?
I am also wondering how I am able to input my own parameters for my vehicle for the calculation of aero drag, rolling resistance etc.? When I double click the block I see there is an equation typed in but I am unable to locate where the parameters are within the MATLAB workspace.
Many thanks, Matt
kartik kanchan on 11 Jan 2018
Please tell me gain is selected on what bases and how to input values in DrCycles.US06 and what values
DEEPA ANAND on 27 Mar 2019
Can you please tell me how the PID tuning is done for both driver glider and BEV system.

Christoph Hahn on 16 Oct 2017
Edited: Christoph Hahn on 16 Oct 2017
Hi Matt,
the model is a closed-loop control system. The PID block gets the difference between desired speed (from drive cycle) and actual vehicle speed as input. It then increases or decreases the tractive force so that the difference is minimized. It is not solving an equation. Does that explanation make sense?
Cheers Christoph
Mathew Lindley on 16 Oct 2017
Hi Christoph,
Thank you for the reply. I understand that the PID block is calculating the error between vehicle speed and drive cycle speed, however I am unable to understand how this result models the tractive force. My understanding is that the difference between two speeds would result in another speed.
Apologies if I am missing something obvious however vehicle modelling is very new to me.
Matt

Christoph Hahn on 16 Oct 2017
Consider the tractive force to be an input to the vehicle model, so that the car reaches a desired speed.
For example, this is similar to your foot hitting the accelerator / brake pedals on a speed limited road that has hills.
Mathew Lindley on 16 Oct 2017
Okay I believe I am closer to understanding the model.
So to recap, let’s imagjne that I provide drive cycle data involving speed and time, the tractive force can be determined from the error between the vehicle speed and drive cycle required speed?
Thanks
Matt