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Create Steering Frame VI

LabVIEW 2013 Robotics Module Help

Edition Date: June 2013

Part Number: 372983D-01

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Owning Palette: Advanced VIs

Requires: Robotics Module

Creates a steering frame of the type you specify. You must manually select the polymorphic instance to use.

You also can generate a steering frame in an interactive dialog box.

Details  Examples

Use the pull-down menu to select an instance of this VI.

Create User Defined Steering Frame

wheels contains an array of references to steering frame wheels. Use the Create Wheel VI to generate these LabVIEW class objects.
wheel x positions specifies the x-coordinates of the wheels with respect to the center of the steering frame. Negative values represent positions to the left of the center, and positive values represent positions to the right of the center.
wheel y positions specifies the y-coordinates of the wheels with respect to the center of the steering frame. Negative values represent positions to the rear of the center, and positive values represent positions to the front of the center.
error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
wheel frame angles (rad) specifies the angles of the wheel frames, measured counterclockwise from the direction of forward travel of the steering frame as viewed from above. A frame angle of 0 is parallel to the direction of forward travel of the steering frame.
steering frame out is a reference to the steering frame. You can wire this output to other Steering VIs.
error out contains error information. This output provides standard error out functionality.

Create Differential Steering Frame

Note Note  This VI instance creates a steering frame that consists of two fixed wheels. The center of a differential steering frame is at the midpoint of wheel separation.

wheels specifies the wheels to associate with the steering frame. Use the Create Wheel VI to generate these LabVIEW class objects.
Left Wheel defines the left wheel of a differential steering frame with respect to the frame of reference of the steering frame.
Right Wheel defines the right wheel of a differential steering frame with respect to the frame of reference of the steering frame.
wheel separation specifies the distance between the wheels.
error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
differential steering frame out contains the steering frame you define.
error out contains error information. This output provides standard error out functionality.

Create Ackermann Steering Frame

Note Note  This VI instance creates a steering frame that consists of two steering front wheels and two fixed rear wheels. The center of the steering frame is at the midpoint of the wheel separation width between the rear wheels.

wheels specifies the wheels to associate with the steering frame. Use the Create Wheel VI to generate these LabVIEW class objects.
Front Left Wheel defines the front left wheel of a steering frame with respect to the frame of reference of the steering frame.
Front Right Wheel defines the front right wheel of a steering frame with respect to the frame of reference of the steering frame.
Rear Left Wheel defines the rear left wheel of a steering frame with respect to the frame of reference of the steering frame.
Rear Right Wheel defines the rear right wheel of a steering frame with respect to the frame of reference of the steering frame.
wheel separation width specifies the distance between the wheels on the left and right sides of the steering frame.
wheel separation length specifies the distance between the front and rear wheels of the steering frame.
error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
ackermann steering frame out contains the steering frame you define.
error out contains error information. This output provides standard error out functionality.

Create Mecanum Steering Frame

Note Note  This VI instance creates a steering frame that consists of four Mecanum wheels. The center of the steering frame is at the midpoint of the rectangle formed by the four wheels.

wheels specifies the wheels to associate with the steering frame. Use the Create Wheel VI to generate these LabVIEW class objects.
Front Left Wheel defines the front left wheel of a steering frame with respect to the frame of reference of the steering frame.
Front Right Wheel defines the front right wheel of a steering frame with respect to the frame of reference of the steering frame.
Rear Left Wheel defines the rear left wheel of a steering frame with respect to the frame of reference of the steering frame.
Rear Right Wheel defines the rear right wheel of a steering frame with respect to the frame of reference of the steering frame.
wheel separation width specifies the distance between the wheels on the left and right sides of the steering frame.
wheel separation length specifies the distance between the front and rear wheels of the steering frame.
error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
mecanum steering frame out contains the steering frame you define.
error out contains error information. This output provides standard error out functionality.

Create Steering Frame Details

When you use the Steering VIs to create and operate on a steering frame and wheels, always use a consistent unit of measurement when you specify values that represent distance.

Steering frames that are not user-defined require certain wheel configurations. When you add wheels whose properties conflict with the steering frame definition, LabVIEW coerces the wheel properties. For example, if you add a Mecanum wheel to a Mecanum steering frame, LabVIEW coerces the roller orientation of the wheel to the value the steering frame requires given the position of the wheel on the frame, if necessary.

Examples

Refer to the following VIs for examples of using the Create Steering Frame VI:

  • labview\examples\robotics\Steering\3D Mecanum Robot\3D Mecanum Robot.lvproj
  • labview\examples\robotics\Steering\Differential Steering\Differential Steering.lvproj

 

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