Designing a Mechanism

You can use the Mechanism Manager to set up a mechanism. This reference provides general information about accessing and using the Mechanism Manager.

This page discusses:

See Also
Engineering Connection Best Practices

About the Mechanism Manager

To assemble a mechanism, you need to add a predefined set of engineering connections (also referred to as joints) to determine how the components move with respect to each other.

The Mechanism Manager allows you to associate a set of joints to an existing mechanism. Use the mechanism manager to:

  • Display a status of the existing mechanism (degrees of freedom, can be simulated or not)
  • Add and/or remove joints from a mechanism (Include/Exclude). The joints referenced by a mechanism are solved during simulation execution.
  • Activate or deactivate existing commands on joints (either angle driven or length driven).
    Important:
    • A joint that is not associated to any mechanism is not taken into account (neither during animation nor simulation).
    • There can be multiple mechanisms but only one can be controlled by the resource motion controller. However, since two different mechanisms can reference the same joint, the recommended methodology is to create a mechanism that contains all required joints of the different mechanisms.
    • To reverse the sense of motion of a command, modify the command value parameters see step 5 in Defining a Mechanism

Accessing the Mechanism Manager

Mechanism Manager is available in the Assembly Design app. To access it, select a mechanism in the tree and select the command from the Mechanism Edition Toolbar. The Mechanism Manager dialog box is displayed, and allows you to specify the joints for the selected mechanism.

The parameters available in this dialog box can be modified. The following options are available:

  • Status: gives the current DOF value of the mechanism.
    Important:
    • The DOF value is updated automatically when you add or remove a command.
    • A mechanism can be simulated when the DOF value is 0.
  • Connection list: lists all available connections you can include in the current mechanism. You can filter the list content by selecting either Only included connections or All existing connections in the current session.
    • Included column: lists connections already included.
    • Name: provides the name for the connection.
    • Type: provides the type for the connection.
    • Command 1/Command 2: list the possible angle / length commands (value Yes or No) if previously specified in the Assembly Design app.

For more information, see Creating Engineering Connections For Mechanisms.

  • Connection Management: includes or excludes connections in the current mechanism.
  • Command Management: adds or removes angle and length commands on selected connections. These options are connection-dependent: i.e., available only if the command type is compatible with the selected connection, and if an angle or length value is already specified in the engineering connection (done at creation time in Assembly Design app). For example, a revolute connection can be angle driven only. For more information, see Engineering Connections and Degrees of Freedom - Summary Table.

Remark: New mechanisms for an Assembly are created via the Mechanism Representation command, available in the Mechanism Edition toolbar of the Assembly Design app. Other commands available in the Mechanism Edition toolbar are Mechanism Manager, Kinematic Simulation and Transient Mode.

Using Compound Engineering Connections

Compound connections (Gear, Rack, Cable) can be used to link the behavior of Prismatic and Revolute Engineering connections. Compound connections may be included in a mechanism of a resource, however all of the commands of the mechanism should be independent. For example, if a Gear is included in the mechanism, only one of the Revolute Engineering connections of the gear should be used as a command. If both of the Revolute connections are used as commands, the simulation behavior will be unpredictable.

For more information on Compound Engineering Connections, see Engineering Connections and Degrees of Freedom in the Mechanical Systems Design User Guide.