About Using Design Tables for Law Excitations

You can assign a design table to law excitations. A design table assigns discrete distance or angle values to each time increment in a kinematics simulation. For each time increment, a distance or angle value is assigned to a command, and the configuration of the mechanism is recalculated accordingly.

This page discusses:

See Also
About Interpolation of Time Increments
Creating a Position Law Excitation
Creating a Velocity Law Excitation

Creating a Design Table

To assign a design table to an excitation, you must first create an excitation and associate it with a command.

Note: You can leave the Formula field empty when you define the initial excitation.

Create an excitation to generate time and command parameters. You can then reference these parameters in a design table.

Note: To include multiple commands in a design table, create one excitation for each command.

To define a design table, from the Tools section of the action bar, click Design Table .

Defining the Parameters

For each excitation driving a command, specify the time increments and the corresponding distance or angle value. To drive multiple commands using multiple excitations, you can either:

  • Specify the same time increments to every command
  • Specify different time increments to each command

If you specify a single time parameter in the design table, all command values in the table are defined according to this time parameter.

Note: You can associate the time parameter to any of the commands in the scenario.

In the following design table, the same time parameter is used for the 3 commands.

Excitation.1\Time(sec) 0 1 2 …
Excitation.1\Length(mm) 5 7 10 …
Excitation.2\Length(mm) 3 0 3 …
Excitation.3\Angle(deg) 45 50 55 …

If you specify multiple time parameters in the design table, you must include the time parameters for every command that appears in the table. Each command value is defined according to a corresponding time increment.

In the following example, a specific set of time increments is used for each of the 3 commands.

Excitation.1\Time(sec) 0 1 2 …
Excitation.1\Length(mm) 5 7 10 …
Excitation.2\Time(sec) 0 3 6 …
Excitation.2\Length(mm) 3 8 10 …
Excitation.3\Time(sec) 0.5 4 5.5 …
Excitation.3\Angle(deg) 45 70 30 …

Defining the Parameters for Interdependent Commands

A command is considered as independent when its defined values have no impact on the values from another command. In a design table, if every command is independent, you must assign a value to each command, and for each time increment. No empty cells can appear in the design table.

Commands are considered as interdependent when the values of one of the commands can be inferred from the values of another command. In that case, one of the commands must be considered as the main command.

Assign values to the main command, and leave the cells corresponding to the other commands empty. The values for the other commands are calculated during the simulation.

You can select a different main command for each time increment. However, for each time increment, you can only assign a value to a single interdependent command. If you assign values to multiple interdependent commands, the mechanism simulation might not work if the command values do not comply with the interdependency rules.

For more information on design tables, see Knowledge Basics User's Guide:Design Tables.