Hi Alex,
I understand that you are encountering a transient initialization error during the simulation of your Simscape model. This is a very generic error and could have occurred due to several reasons. This error commonly occurs when a model is excessively idealized, resulting in abrupt transitions that prevent the solver from converging. In such cases, the solver may attempt transient initialization. Assuming that you have correctly tried the things which you have mentioned and achieved no positive result, here are a few more things you can check for:
- Avoid Using Memory Block to Break Algebraic Loops: One of the reasons for this behaviour may be the use of a memory block to break algebraic loops in a continuous model. This is not recommended, as it can cause numerical problems. Refer to this blog post for more information: https://blogs.mathworks.com/simulink/2015/07/18/why-you-should-never-break-an-algebraic-loop-with-with-a-memory-block. You can replace the memory block with a transfer function with a time constant of X seconds (you can adjust as needed). It is generally better to drive a continuous Simscape model with continuous input signals, as is the case with the aforementioned transfer function.
- Simplify the Model: This includes removing unnecessary sensors since these add extra equations. You can get the plots after running the simulation using the MATLAB file exchange command `ssc_explore`, without using sensors. To get more information on this submission, please refer to the following link on MATLAB Central: http://www.mathworks.com/matlabcentral/fileexchange/28184 Additionally, instances of multiple resistors in series could be combined into one, and combining other components, etc.
- Incremental Building and Testing: You are encouraged to start with a simpler version and gradually build up before it gets to this level. After confirming that it gives expected results at smaller levels (including looking for correct initial states) you could then start to combine the pieces. This is because debugging small models is always easier.
- Use the Solver Profiler: Use the Solver Profiler to determine what the solver is doing just before you receive the error. In the step size tab, you should see a graph showing the step spike down as it approaches the time of the error occurring. If you zoom in on that spike, there should be more information, such as an indication that there is a zero crossing. The following link contains more information on the Solver Profiler: https://www.mathworks.com/help/releases/R2020b/simulink/slref/solverprofiler.html
You may refer to the following documentation to learn more about troubleshooting simulation errors:
Feel free to share your model and other associated files to help debug better in case the issue persists.
I hope these suggestions help you resolve the issue with your Simscape model.
