Simulation and Animation of a Quarter-Car Automotive Suspension Model

A standard linear quarter-car model is simulated and then animated.

Description

This model was developed for use in teaching modeling, simulation, and optimization in graduate engineering courses. The simulation is particularly useful for demonstrating different simulation designs that are optimized for different applications (e.g., maximum handling capability, maximum comfort, etc.). The model is based on the electric vehicle case study found in this dissertation:

http://deepblue.lib.umich.edu/handle/2027.42/58449

This code was used in the creation of this corresponding video, used for teaching:

http://www.youtube.com/watch?v=_jKceIHn6tc

Note: this submission does not include code for the multi-objective optimization highlighted in the youtube video.

• Required Products: MATLAB
• MATLAB release: MATLAB 7.13 (R2011b)

[James Allison]

Alexandru: Perhaps there is another function 'ss' on your path that is superseding the built-in ss function:

http://www.mathworks.com/help/control/ref/ss.html

You can use the 'which' command to find out if this is the issue.

Another possibility is the ss is part of the control system toolbox. If you don't have that toolbox, then ss will not work.

[Alexandru]

Hello,

I am interested in your app. But I have problems when running it. I get this error:
Undefined function 'ss' for input arguments of type 'double'.

Error in sim_qcar (line 48)
qcar = ss(Aqcar,Bqcar,Cqcar,Dqcar);

What am I missing?
Thank you!
Alex

[James Allison]

umf is a multiplication factor that allows quick exploration of road profiles with different levels of roughness. It should be set to 1 for the output to correspond to the road profile in the .mat file.

Nice catch Louis. Yes, dt should be changed to dt2 on line 62.

[Louis]

Very helpful model, I have two comments though:
1. I think umf should be set to 1 (or removed)
2. on line 62 the division by dt should be changed to a division by dt2

These two details made the script output inaccurate results; the script otherwise gives consistent results.

[Chegireddy Venkateswara Reddy]

nice demo

[Mayur]

James,

Thanks for this model. I am trying to understand what umf = 3 is, and why you have used it. Could you please explain.

Thanks,
Mayur

[Olexander Zhytenko]

very nice !!!