Initial Alignment Options for the ATS800

The ATS800 is unique among laser trackers in that it offers a wide range of automated measurement options. Most of these automation require an initial alignment to the part. Below are a list of options to help facilitate initial part alignment for these applications where either surface point or feature measurement are used.

 

Feature Based Best Fit

The Measure Geometry-Based Alignment was added specifically for the ATS800. It offers the ability to be guided through feature measurement for the initial alignment process. To perform this operation follow these steps: 

  1. First build Features from a CAD model using the From CAD button. Features can also be build using imported geometry if needed. To do so use the option under the Nominal section of the Features tab. These features need to be point reducible such as Circles or Spheres.

  2. Configure these features for Geometry measurement by right-clicking on one of them selecting Geometry as follows:

    Use the Configure instrument button to apply these settings to all other similar features.

  3. Select the Best-Fit button from the features section or the Measure Geometry-Based Alignment option from the drop-down list on the Alignment tab.

  4. Select the geometry you wish to include in the operation and press OK to start the alignment process:

    Three dialogs will open:

    Because the instrument is not yet aligned you will need to manually guide the instrument to a feature and define it within the OVC.

    Close the OVC window to measure and move to the next feature in the list. The instrument will measure and open the window again to allow selection of the next feature.

  5. When all the features are measured the Nominal Geometry Relationship alignment Best-Fit window will open automatically. Press the Re-fit button to compute the transform. This will report the relative difference between the center of each nominal and each measured feature.

  6. Press the Apply Transform button to complete the operation.

 

Nominal Geometry Relationships

The Nominal Geometry Relationship alignment uses point reducible features to perform a best fit, just without the measurement automation, and can be used with any instrument. More information on the Nominal Geometry Relationship alignment can be found here. If an automated measurement process is not needed, and the GR-Features have both a measured and a nominal geometry, This option can be used directly as well.

  1. Build at least 3 point reducible features from CAD. This includes Circles, Slots, and Sphere features. You can also use the Average point feature for point specific locations.

  2. Open the OVC and measure those features.

  3. Right-click on each and assign the corresponding nominal.

  4. Select Align>Nominal Geometry Relationships

    This operation will open a best fit solution between the nominal and measure feature center points.

 

Quick Align

Quick align to CAD is a great way to perform an initial alignment to a part where 3 perpendicular planes are visible from the instrument. This can be done fully from the OVC camera.

Selecting the nominal points.

  1. Import or open a file with a CAD model

  2. Add an instrument station and connect to the instrument

  3. From the Menu select Quick Align:

  4. Select points on 3 perpendicular faces (3-2-1), (does not use circles or slots)

  5. Open the OVC and measure the corresponding points by clicking in the graphics on the part in each sequential position.

    More details on Quick Align can be found here.

 

 

Basic Alignment Options

In addition to feature measurements its also very reasonable to use a reflector to measure the point and any traditional laser tracker alignment strategy can also be used. For a review of other alignment options refer to the Alignments Tab.