A Multiple Sensor, Geometrically Corrected Co-ordinate Measuring Machine System

This paper describes a modular and open Co-ordinate Measuring Machine architecture that merges quasi-static thermally compensated geometric error compensation with multiple data collection sensors. The complete system consists of thermocouples attached to the CMM and part, a motion control computer, trigger and analogue touch probes, and a non-contact laser digitiser. To simplify error correction algorithm implementation, motion control is performed directly on a Pentium based microcomputer. Linear scale quadrature signals are used to synchronise the sensor data with the CMM position, and ethernet provides data interconnection amongst the components. Use of the laser digitiser reflected light intensity with calibrated artefacts is proposed as a promising and practical self calibration method.