CODEWITHSUNDEEP
modelicadymola
A.Gharbi
A.Gharbi

Reputation: 759

Limiting torque in revolute joint

I am trying to model a contact between two bodies, one of them is moving up and down and the other is rotating (think of the cutting process of a rotating piece). I am using the IdealizedContact library for the contact part (please check the image below). enter image description here

I am giving the revolute joint a speed input and I want to see the effect of friction from the contact block on the angular velocity of the spindle component. I am unable to do that. Any change of the attributes in the contact block results in a change of the torque in the revolute joint but the speed remains constant. Is there a way of having the torque constrained in the joint? or what should I do to observe the friction effects (slow down or acceleration in the spindle speed)?

PS: I am using Dymola

Upvotes: 1

Views: 268

Answers (2)

Hans Olsson
Hans Olsson

Reputation: 12517

It is not directly possible to see everything from the diagram, but to investigate how friction changes the "steady-state" speed of a component at a given speed it is good to have:

  • Two friction components:
    • one clutch-like (allowing loss between the drive and the component)
    • one bearing-friction-like (allowing loss between the component and the environment)
  • Inertia/Mass of the component

Upvotes: 2

AlCap
AlCap

Reputation: 21

Disclaimer: this is most likely not a fully featured answer, but hopefully it will provide you with a good starting point.

This is related to your way of modeling. You define the input speed to be exactly 100 rad/s . Hence the simulation will always provide you this exact speed. To improve your results, you could try to give a force input to your joint and do some kind of torque control with a PD controller or even better try a constant torque input and observe the effect on the speed.

You could also try to provide a min max constraint on the torque in the declaration of your revolute component as an additional modifier, see the modelica language reference for that.

Upvotes: 2

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