sh_cyl_cou​nterbalanc​e_valve example: artificial results when 0 input?

Using sh_cyl_counterbalance_valve to help diagnose my own model.

When inputting no load or flow rate to the example model, simscape results explorer shows that there is still pressure being exerted on blocks such as the valve, cylinder, damper, pressure relief valve, etc. There are large spikes at the beginning. I would expect with no input or load that nothing would happen.

I don't think this is a real output and is an artificial result? Why would this be happening, is there a way to prevent these sharp spikes?

Answer 1

[Yifeng Tang]

Hi Chris,

I tried to make Load and Flow Rate blocks zero and seem to get what you saw as well. Look like the initial "spike" comes from the initial pressure set in the cylinders: 48e5 and 14e5 Pa. If you change those numbers, you will get less an initial spike.

To find out the actual initial conditions the model applies, you can try the variable viewer tool:

https://www.mathworks.com/help/simscape/ug/variable-viewer.html