Solver Configuration error in electro-mechanical SIMSCAPE model

Hello everyone,

I am trying to build a mechanical system controlled by an electric actuator and controller in simscape. However, when I use one Solver Configuration for the whole system, I got this message[[ Not enough input derivatives were provided for one or more Simulink-PS Converter blocks associated with the highlighted Solver Configuration block, for the solver chosen. Implicit solvers (ode23t, ode15s, and ode14x) typically require fewer input derivatives than explicit solvers, and local solvers never require any. You can provide more input derivatives by selecting different options (including turning input filtering on or increasing the number of user-provided input derivatives) on the Input Handling tab of Simulink-PS Converter blocks linked]]. And when I add another Solver Configuration, I got different message [[ Multiple Solver Configuration blocks connected to Physical Network. Each physical network must be connected to exactly one Solver Configuration block]]

If any one has any information about how to solve this problem, that would be really appreciated.

Thanks all

engmoh

[Adedayo]

You can check the link below for possible solutions.

http://www.mathworks.com/matlabcentral/answers/122860-problem-with-solver-in-the-simscape-simmechanics-interface

Answer 1

[Sabin]

I do not know how the model looks like, but the error points to not enough input derivative from Simulink to Simscape via Simulink-PS Converter.

The Simulink-PS Converter block converts the input Simulink signal into a physical signal. Use this block to connect Simulink sources or other Simulink blocks to the inputs of a Simscape physical network.

When simulating a model, you may need to provide time derivatives of some of the input signals, especially if you use an explicit solver. One way of providing the necessary input derivatives is by filtering the input through a low-pass filter. Input filtering makes the input signal smoother and generally improves model performance. The additional benefit is that the Simscape engine computes the time derivatives of the filtered input. The first-order filter provides one derivative, while the second-order filter provides the first and second derivatives. If you use input filtering, it is very important to select the appropriate value for the filter time constant. The filter time constant controls the filtering of the input signal. The filtered input follows the true input but is smoothed, with a lag on the order of the time constant that you choose. Set the time constant to a value no larger than the smallest time interval in the system that interests you. If you choose a very small time constant, the filtered input signal is closer to the true input signal. However, this filtered input signal increases the stiffness of the system and slows the simulation. Instead of using input filtering, you can provide time derivatives for the input signal directly, as additional Simulink signals. If the provided derivatives are inconsistent with the input signal, then some of the quantities may be incorrect during simulation.

Depending on the solver configuration you will need or not to provide the additional derivative.

Each physical network must be connected to exactly one Solver Configuration block. You can split the network using Simulink blocks and then have two separate physical networks that can have their own solver configuration if needed but most likely this is not needed given the information we have.