MV-7009: Remote Co-simulation with Simulink

In this step, use a single body vector force (Force_Vector_OneBody) to model the control force in MotionSolve. The force on the cart is calculated as:

$$F_{cart}=F_{control}+F_{dist}$$, where

$$F_{dist}$$ is the disturbance force,

$$F_{control}=K_1\left(erro{r}_{\theta }\right)+K_2\left(erro{r}_{\omega }\right)+K_3\left(erro{r}_x\right)+K_4\left(erro{r}_{\dot{x}}\right)$$ is the control force,

$$K_i$$ are gains applied to each of the error signals

$$error$$ is the error (difference between reference and actual values) on the input signals.

The angular displacement and velocity of the pendulum are obtained by using the AY() and WY() expressions respectively. The translational displacement and velocity of the cart are obtained similarly, by using the DX() and VX() expressions.

A MotionSolve model needs a mechanism to specify the input and output connections to the Simulink model. The MotionSolve model (XML) used above is modified to include the Control_PlantInput and Control_PlantOutput model elements and provide these connections. In this tutorial, this has already been done for you, and you can see this by opening the model InvertedPendulum_Cosimulation.mdl from your <Working_Directory>.

This model contains two additional modeling components:

• The Control_PlantInput element defines the inputs to a mechanical system or plant. For this model, only one input is defined in the "Plant Input Simulink" solver array. This is set to the ID of the solver variable that holds the control force from Simulink.

  
  
  Figure 5. The Definition of the Input Channel to MotionSolve

• The Control_PlantOutput element defines the outputs from a mechanical system or plant. For this model, four outputs are defined in the "Plant Output Simulink" solver array. These are the pendulum rotation angle, the pendulum angular velocity, slider displacement and slider velocity.

  
  
  Figure 6. The Definition of the Output Channels from MotionSolve

  The inputs specified using the Control_PlantInput and Control_PlantOutput elements can be accessed using the PINVAL() and POUVAL() functions, respectively. Since the Control_PlantInput and Control_PlantOutput list the ids of solver variables, these inputs and output variables may also be accessed using the VARVAL() function. For more details, please refer to the MotionSolve User's Guide on-line help.

  This model has the following connections:

  • Plant Input: A single control force that will be applied to the cart.
  • Plant Output: The pendulum's angular displacement and angular velocity; the cart's translational displacement and velocity.

An example of the usage of these commands is listed below:

The core feature in Simulink that creates the co-simulation is an S-Function (System Function) block in Simulink. This block requires an S-Function library (a dynamically loaded library) to define its behavior. MotionSolve provides this library, but the S-Function needs to be able to find it. To help MATLAB/Simulink find the S-Function, you need to add the location of the S-Function to the list of paths that MATLAB/Simulink uses in order to search for libraries.

The S-Function libraries for co-simulation with MotionSolve is called mscosimipc – for Inter Process Communication (IPC) using TCP/IP sockets for communication.

This file is located at <altair>\hwsolvers\motionsolve\bin\<platform>.

The location of this file needs to be added to the search path of MATLAB for the S-Function to use mscosimipc.

This can be done in one of the following ways:

If you exercise Option 2 above, then the list of files that need to be copied/installed on the machine where Simulink is located include the following: