Prepare the Simcenter 3D Motion Model

Inside Simcenter 3D, the models consist of an external control element. Inputs consisting of position or velocity data are usually fed into the external control block while force and torque outputs are returned from Simcenter Amesim.

Creating Control Input and Output Elements

control input and output elements

In a coupled simulation the user should use the control input and control output elements to communicate with Simcenter Amesim. The reason for this is the 'sensor' elements on the mechanism models of all position, velocity, and acceleration sensors have to be passed on to Simcenter Amesim. You do this with the menu Insert > Control > Control Input

Create the 'sensor' elements = displacement, velocity, acceleration (translational and rotational) measured on any links of the mechanism with Control Input elements.

Creating the Mechatronics Connection Element

The Mechatronics element is a separate block inside Simcenter 3D Motioncontrol element, which imports a model that has been exported from Simcenter Amesim. The first step in the model is to create a Mechatronics element. You do this with the menu Insert > Control > Control > Mechatronics. This will bring up the dialog box shown below:

Simcenter 3D Motion Mechatronics interface (Input Ports tab)

Figure 7: Mechatronics dialog box

First, you must make sure that Amesim is selected from the Type drop-down list. Then you must select the Import option, in order to import the Simcenter Amesim model into Simcenter 3D Motion. When you select a valid Simcenter Amesim model from the Model File section (depending on the type of interface block defined in the Simcenter Amesim model) the Integration Type is automatically displayed. In this case, Model Exchange will be displayed. Simcenter 3D Motion is able to automatically retrieve the input and output nodes from Simcenter Amesim: in the Input Ports tab a list of all detected inputs from Simcenter Amesim is displayed (column Name), as well as the corresponding control input ports in Simcenter 3D Motion: the association is made automatically by name. If different names are used it is always possible to select any input and manually associate any existing port. Scale factors and offsets can also be applied to any input elements.

Watch Variables

Simcenter Amesim Watch variables can be exported back into Simcenter 3D Motion for post-processing (see figure below). Watch variables are reported during the solution process and are available for plotting inside Simcenter 3D Motion.

Figure 8: Watch Variables tab

Watch Parameters

Simcenter Amesim Watch parameters can be imported into Simcenter 3D Motion. This allows the parameters to be managed and altered from within Simcenter 3D Motion.The figure below shows the layout of the Watch Parameters tab.

Figure 9: Watch Parameters tab

Note

Information on creating Watches is given in the Simcenter Amesim Reference guide.

Creating Control Output Elements

In the Output Ports tab (see below) it is possible to see the list of available output elements as imported from Simcenter Amesim: these will represent the output data from Simcenter Amesim and applied to the Simcenter 3D Motion mechanism, typically forces and moments.

Figure 10: Output Ports tab

In order to define where these outputs will be applied, control output elements still need to be created outside the Mechatronics interface:

Use the menu Insert > Control > Control Output.

Each control output element will have to be manually associated with a corresponding output port in Simcenter 3D Motion.

Set up the Simcenter 3D Motion Solver Solution Parameters

Simcenter 3D Motion solver

Simcenter 3D Motion solver solution parameters

A combined Simcenter Amesim/Simcenter 3D Motion coupled solution requires a valid solution to be created in the model. The user can add a solution to the Simcenter 3D Motion navigator by going to Menu > Insert > Solution. When you double-click the Solution the following dialog is displayed:

Figure 11: Solution dialog box

You should set the Analysis Type to Kinematics/Dynamic for a coupled Dynamic simulation.

The BDF solver is based on DASSL and is similar to the Simcenter Amesim solver. The Simcenter 3D Motion solver will also handle the Simcenter Amesim discontinuities by locating the discontinuities in time and restarting itself on the other side of the discontinuity.