Calibration of a 3D working space by multilateration

• Identification of parametric errors by multilateration using a unique Laser Tracer.
• Definition of a reference measuring system independently of the CMM kinematics.
• Evaluation of uncertainties associated to CMM parametric errors.
• A priori assessment of the calibration procedure in terms of uncertainty.

This paper deals with a calibration procedure of a 3D working space based on multilateration using a unique tracking interferometer. The key point of the procedure, detailed for a Cartesian CMM, is the definition of a reference measuring system built from the successive locations of a single tracer independently of the machine kinematics. Procedure limits are thus highlighted and can be classified into three types: limits of the devices (interferometer and measuring rule performances), limits linked to the use of a single tracer (reflector reorientation for visibility purposes), and limits linked to the algorithm. To evaluate associated uncertainties, a virtual measurement module has been developed which simulates a realistic 3D calibration and allows the study of the influence of each uncertainty component on the calibration procedure. The approach applied to the calibration of a virtual CMM proves that the simulation module is an efficient tool to investigate uncertainties associated with calibration procedures based on multilateration using a single tracer.