Ideal position (translation/rotation) source in Matlab/SimScape?

Hello,

I'm would like to apply a defined displacement over time onto a Simscape Model.

It seems there's only a "velocity" and "force" source element. Is there a best practice for modelling a position source?

I've tried to simply use my time-position and connect it to a derrivation block to get a velocity-demand to use in a velocity-source. With a high amount of single position-exitations this leads to a drift in position due to small inaccuracies.

Best regards,

Daniel

[Zheng]

IF I understood u correctly

Perhaps you can simply use ideal force source to power mechanical blocks and use the "Translational Hard Stop" Block to lock the upper and lower limit of displacement. at least thats what I am doing to limit the input rod of Master Cylinder in a car

Answer 1

[Vidip]

I understand that you are trying to differentiate your position signal to get a velocity signal and then feed that into a velocity source, but you are getting drifted position due to small inaccuracies.

While using the derivative block, the model needs to follow a specific set of guidelines which are mentioned in the below link and if not possible there are certain alternatives mentioned to reduce the number of inaccuracies which are observed in the results –

• https://in.mathworks.com/matlabcentral/answers/95614-what-are-the-implications-of-using-the-derivative-block-in-simulink

Also, try implementing a feedback control system that uses a PID controller to ensure the position tracks the desired trajectory by comparing the actual position with the desired position and adjusting the velocity input accordingly.

For further information, refer to the documentation links below:

• https://in.mathworks.com/help/simscape/ref/simulinkpsconverter.html
• https://in.mathworks.com/help/simulink/slref/pidcontroller.html
• https://in.mathworks.com/matlabcentral/answers/261223-simscape-the-derivative-of-position-in-a-direction-not-equal-to-the-velocity