Patent ID: 11964394
Assignee: RENISHAW PLC
Field: Measurement (Instruments)
Classification: CPC B  G | IPC B  G

Claim 0:
1. A method of calibrating a coordinate positioning machine, a geometry of the machine being characterized by a parametric model and the calibration method being intended to determine a new set of model parameters that characterizes the geometry of the machine better than an existing set of model parameters, the method comprising:
controlling the machine into a pivot pose in which a target point associated with a moveable part of the machine and a pivot point associated with a fixed part of the machine are separated from one another by a known separation;
determining an error value for the pivot pose based on the known separation and a separation expected for the pivot pose from the existing set of model parameters;
controlling the machine into a plurality of different target poses;
for each target pose, (i) measuring a separation between the target point and the pivot point and (ii) determining an error value for that target pose based on the measured separation and a separation expected for that target pose from the existing set of model parameters;
determining an overall error measure from the error values; and
determining a new parameter set that would result in a lower overall error measure than for the existing set of model parameters.