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Glossary
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Controller
A controller is provided as a way to try and reach a desired (target) value by means of a feedback control loop.

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Reference
View the glossary, frequently asked questions, and errors and alerts.
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  - Alternative
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  - Connection Stiffness
    Connection Stiffness allows for better approximation of axial and shear stiffness in grounded fasteners, grounded joints, and cylindrical supports.
  - Controller
    A controller is provided as a way to try and reach a desired (target) value by means of a feedback control loop.
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    A load case is a set of loads and supports, displacements, accelerations, and temperatures that act on a model at one time.
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    The modeling window, sometimes referred to as the graphics area or window, is where you interact with your model.
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    Applying pretension to bolted and screwed connections allows a more complete understanding of the behavior of a structure.
  - Principal Axes
    The principal axes or global axes are the x, y, and z axes in the View Rotator.
  - Profile Functions
    Motors and actuators have a profile option on the microdialog that allows you to change how the shaft moves as time elapses (or another independent variable changes).
  - Property Editor
    The Property Editor shows all the properties of a selected object and allows you to edit them.
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    The ribbon allows you to quickly access tools and standard functions, and is located at the top of the Inspire workspace.
  - Screen Capture
    The Screen Capture tool saves an image of your model with a white background.
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    The Snaps Filter icon is located in the lower right corner of the application window. It opens the snaps menu.
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    The status bar displays model status information and includes the snaps filter and unit system selector.
  - Suppress (Unsuppress) Entities
    Suppress and Unsuppress joints, fasteners, and motion entities in a model.
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    Use the Unit System Selector to change the display units used in the user interface. (These can be the same or different as the modeling units, which are set in the Preferences.)
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    The view controls are located in the lower left corner of the modeling window.
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    When in sketch mode, the Rotate to Closest Principal Axes icon is replaced with the View Normal to Grid icon in the view controls.
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    Use the View Rotator to achieve finer control of rotation than is possible by using the mouse.
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    Most tools on the ribbon include text prompts beneath the tool or guide bar that explain what to do next. These prompts are a form of user assistance called workflow help.
Keyboard Shortcuts and Mouse Controls
Learn keyboard shortcuts and mouse controls for common operations.

Controller

A controller is provided as a way to try and reach a desired (target) value by means of a feedback control loop.

Motors and actuators use a controller by default, but have an option on the microdialog

that allows you to disable the controller.

Figure 1. Controller Option for Motors

Figure 2. Controller Option for Actuators

Types of Controllers

There are two types of controllers available from the Property Editor:

PID
Soft Constraint (available for angle motors and displacement actuators only)

Note: In general it is recommended to use a controller, but if your controller is not doing what you want, try turning it off. The selected profile function will be used directly with no feedback loop involved.

PID Controller

PID is a conventional Proportional-Integral-Derivative (PID) control scheme. If the controller does not respond the way you expect, you can adjust the gains in the Property Editor:

Proportional Gain
Integral Gain
Derivative Gain

Soft Constraint Controller

A soft constraint is not a conventional controller, but more like a mathematical constraint with some violation allowed. (That is why it is a soft constraint, as opposed to a hard constraint which allows no violation.)

You can change the behavior of a soft constraint by adjusting the factors in the Property Editor:

Proportional Factor
Derivative Factor

Example

This plot shows a case of a soft constraint controller overshooting the desired step-dwell-step profile function.