Why is the motion of the shock absorber in my quarter car model seems undamped?

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Shuo Wang 2016-7-11

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https://ww2.mathworks.cn/matlabcentral/answers/294929-why-is-the-motion-of-the-shock-absorber-in-my-quarter-car-model-seems-undamped

回答： Swarooph 2016-7-12

physical_modeling.zip

Dear sir I just followed the tutorial video of Formula student physical modeling training. I have finished the part 9, section2. However, when I run the model. The scope of the shock absorber seems like the SA I defined doesn't reflect the properties of the damper and spring. I attached my model and matlab code in a zip file.My matlab version is 2014b.

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Answer 1

Swarooph 2016-7-12

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Shuo,

First things first, this is not an issue with the system being undamped but that the Scope configuration properties is set incorrectly.

Note on the X axis that your signal logging begins only around ~51 seconds. This means the Scope is not logging your entire simulation results. This is by design because the Scope logs only the last 5000 data points by default (for memory and performance considerations perhaps). Since your simulation is relatively long, it is not plotting ALL the simulation data points. This can be changed using the Scope configuration parameters. Click on the 'gear' icon on the Scope toolbar as highlighted below.

This opens the 'Parameters' of the Scope. Here, choose the 'History' tab as shown below and uncheck the 'Limit data points to last' option.

This makes sure that the Scope will plot all points. When I run the simulation after changing this option, I get the following expected result.

P.S: Please note that all these files were meant to be used with R2015a or later. Some features or results might be incompatible with previous releases.