Perceptron, Inc.

Myles Markey, Jr

Dale R Greer

Brett Hibbard

Stephen James Tenniswood

Jesper Christensen

A temperature compensation system (,) is provided for compensating measurements from a sensor (,). A temperature transducer (,) is placed in close proximity to a manufacturing workstation as a means of measuring the ambient temperature associated with the workstation (,). A reference workpiece (,) is placed within a sensing zone of the sensor (,). The system (,) includes a temperature compensating module (,) that is connected to the sensor (,) and to the temperature transducer (,) for determining a baseline measurement of the reference workpiece at a reference temperature. The temperature compensating module (,) is further adapted for collecting a plurality of measurements of the reference workpiece over a plurality of temperatures for establishing a relationship between these measurements and their corresponding temperature values. In addition, a workpiece measuring module (,) is also connected to the sensor (,) and to the temperature transducer (,) for measuring a first workpiece at a first temperature, whereby the sensor measurement is compensated for temperature using this relationship. In this way, the temperature compensation system (,) compensates the sensor measurement for physical changes in any of the components of the workstation that are caused by fluctuations in ambient temperature. Rather than compensate for ambient temperature changes, the temperature compensation system (,) may also be adapted to compensate sensor measurements based on process driven temperature changes (i.e., a &ldquo;hot&rdquo; workpiece).

Method and apparatus for temperature compensation of measurements from a non-contact sensor

The laser tracker is positioned at a vantage point to detect and calibrate its reference frame to the external reference frame demarcated by light-reflecting retro reflector. A tetrahedron framework with retro reflector mounted on one of the vertices serves as a reference target that is placed in front of the non-contact sensor to be calibrated. The laser tracker reads and calibrates the position of the retro reflector (and thus the tetrahedron) while the structured light of the non-contact sensor is projected onto the framework of the reference target. The structured light intersects with and reflects from the reference target, providing the non-contact sensor with positional and orientation data. These data are correlated to map the coordinate system of the non-contact sensor to the coordinate system of the external reference frame.

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Ann Arbor, MI, United States of America

Myles Markey, Jr