MATLAB: Solver Configuration for Rotational Pneumatic Mechanical Converter

Question

I intended to use " Rotational Pneumatic Mechanical Converter" to convert angular velocity to pneumatic pressure. However it always pop up a solver error:

Nonlinear solver: Linear Algebra error. Failed to solve using iteration matrix. Initial conditions solve failed to converge.

How can I solve it?

Answer 1

If you look at the documentation Modelling Pneumatic Systems, you'll see that it says:

Every node in a pneumatic network must have a defined temperature as well as pressure. This rule places some constraints on how you connect the pneumatic elements. In effect, every node should have a volume of fluid associated with it.

I think your model violates this rule. I added a Constant Volume Pneumatic Chamber block to the node of the A port of the Rotational Pneumatic - Mechanical Converter block, with the thermal port connected to an Adiabatic Cup block, and the model ran just fine.

One note though: you use an Ideal Angular Velocity Source block, but the input to it says "Apply stall torque at t = 0.1s". If the signal is meant to represent a torque, then you should be using an Ideal Torque Source block. If it is meant to represent a velocity, you should change label of the step block. It's confusing to say the least.

HTH,

Arnaud