Mechanical rotation axis measurement system and method
AssigneeNorthrop Grumman Corporation
InventorGordon E. James
Life of this patent
Estimating the term…
Abstract
A system, apparatus (60) and method (20) of determining an average axis of rotation (Wf) and defined center of rotation (Cr) of a rotatable device (10) having a rotation axis which is nominally fixed in global coordinates (X,Y,Z) and having a plurality of target points (P1-PN) affixed thereon. It comprise a data collector (62) for obtaining target point location data from the device target points (P1-PN) for a plurality of rotated positions, a transformer (64) for translating and rotating the target point data in global coordinates, and an iterative algorithm (66) for positioning a secondary coordinate system (U,V,W) to be coincident with the axis of rotation (Wf), and defined center of rotation (Cr) of the rotatable device (10).
Claims28
A system for determining an average axis of a rotatable device, said rotatable device having a measured rotation axis nominally fixed in global coordinates, and having a plurality of target points affixed to the rotatable device, said system comprising:
- a data collector adapted to obtain target point location data from said device target points for a plurality of rotated positions;
- a transformer adapted to rotate and translate the obtained point data;
- and
- an iterative algorithm for positioning a secondary coordinate system associated with the obtained point data to be coincident with the average axis of rotation and center of rotation for at least one rotation axes of said rotatable device.
An apparatus for determining an average axis of rotation for a rotatable device, said rotatable device having a plurality of target points affixed thereon and having a measured rotation axis which is nominally fixed in global coordinates, comprising:
- a data collector adapted to obtain global coordinates of said target points
- at a plurality of rotations of said rotatable device;
- and
- a transformer adapted to translate and rotate by means of Euler rotations said target point global coordinates to position a secondary coordinate system to be coincident with said rotatable device average axis of rotation and defined center of rotation.
A method for determining an average axis of rotation of a rotatable device, said rotatable device having at least one rotation axis which is nominally fixed in global coordinates and having a plurality of target points affixed thereon, said method comprising the steps of:
- obtaining target point location data from said plurality of target points for a plurality of rotated positions of said rotatable device, such that location point data sets are associated with each of the plurality of rotated positions;
- and
- translating and rotating said target point location data of the location point data sets to position a secondary coordinate system to be coincident with said average axis of rotation of said rotatable device including calculating the distance the device rotated between similar target points in the location point data sets.
A system that determines an average axis of rotation and center of rotation of a rotational device, comprising:
- a data collector that receives location data associated with a plurality of target points affixed to a rotational device at a plurality of rotational positions of the rotational device, the location data includes target position coordinates with respect to an initial coordinate system;
- a transformer that employs the location data to translate and rotate a second coordinate system to place an origin of the second coordinate system at a center of rotation of the rotational device and place an axis of the second coordinate system along the average axis of rotation of the rotational device;
- and
- an iterative algorithm that iteratively modifies the translation and rotation of the second coordinate system to optimize a figure of merit calculated from the transformed target point location data.
Dependencies are inferred from the claim text.