Calibrating and operating rotary devices, in particular for rotating probe heads and/or probes of coordinate measuring machines

A method of calibrating a measuring arrangement for determining rotational positions of a rotary device, the rotary device having a first part and a second part that is rotatable relative to the first part about a rotational axis, the method comprising:

• detecting, with a plurality of sensors, measured values of rotational positions of the first part and the second part relative to one another in various rotational positions of the rotary device, the sensors being arranged at various angular positions distributed around the rotational axis;
• generating a measuring signal corresponding to the respectively detected rotational position, to obtain redundant information concerning each of the rotational positions of the rotary device;
• providing a calculation model in which differences in the rotational positions detected by various sensors, and consequently the redundant information, are expressed by:
• translational errors, assigned to the respective sensor, of the detected rotational position that are caused by a translational movement transverse to an extent of the rotational axis;
• measuring errors of the measuring arrangement that are not errors caused by the translational movement;
• and
• angular positions of the sensors about the rotational axis;
• determining from the calculation model the translational errors assigned to the respective sensor and the measuring errors of the measuring arrangement and calibrating the measuring arrangement while taking into consideration the translational errors and the measuring errors of the measuring arrangement.

A method of operating a rotary device, wherein the rotary device has a first part and a second part that is rotatable relative to the first part about a rotational axis, the method comprising:

• detecting, with a plurality of sensors, measured values of rotational positions of the first part and the second part relative to one another in various rotational positions of the rotary device, the sensors being arranged at various angular positions distributed around the rotational axis;
• generating a measuring signal corresponding to the respectively detected rotational position, to obtain redundant information concerning each of the rotational positions of the rotary device;
• providing a calculation model in which differences in the rotational positions detected by various sensors, and consequently the redundant information, are expressed by:
• translational errors, assigned to the respective sensor, of the detected rotational position that are caused by a translational movement transverse to an extent of the rotational axis;
• measuring errors of the measuring arrangement that are not errors caused by the translational movement;
• and
• angular positions of the sensors about the rotational axis;
• determining from the calculation model the translational errors assigned to the respective sensor and the measuring errors of the measuring arrangement;
• and
• correcting the translational errors and the measuring errors of the measuring arrangement during an operation of the rotary device.

A calibrating assembly for calibrating a measuring arrangement for determining rotational positions of a rotary device that has a first part and a second part, which is rotatable relative to the first part about a rotational axis, the calibrating assembly comprising:

• a plurality of sensors disposed at various angular positions distributed around the rotational axis and respectively arranged on one of said first and second parts;
• at least one measuring body, disposed on the other of the first and second parts and assigned to at least one of said sensors, each said sensor being configured to generate a measuring signal in accordance with a rotational position of the measuring body, and consequently in accordance with a relative rotational position of the first and second parts;
• an evaluation device connected to said sensors for receiving measuring signals of said sensors and configured to use a calculation model in which differences in the rotational positions detected by various said sensors, and consequently redundant information, are expressed by:
• translational errors, assigned to the respective sensor, of the detected rotational position that are caused by a translational movement transverse to an extent of the rotational axis;
• measuring errors of the measuring arrangement that are not errors caused by the translational movement;
• and
• angular positions of the sensors about the rotational axis;
• said evaluation device being configured to determine the translational errors assigned to the respective sensor and the measuring errors of the measuring arrangement from the calculation model and to correct the translational errors and the measuring errors of the measuring arrangement for an operation of the rotary device.

A rotary device, comprising:

• a first part and a second part rotatably disposed for rotation relative to said first part about a rotational axis;
• a plurality of sensors disposed at various angular positions distributed around the rotational axis and respectively arranged on one of said first and second parts;
• at least one measuring body disposed on the other of said first and second parts and assigned to at least one of said sensors, each said sensor being configured to generate a measuring signal in accordance with a rotational position of the measuring body, and consequently in accordance with a relative rotational position of said first and second parts;
• an evaluation device connected to said sensors for receiving measuring signals of said sensors and configured to use a calculation model in which differences in the rotational positions detected by various of said sensors, and consequently the redundant information, are expressed by:
• translational errors, assigned to the respective sensor, of the detected rotational position that are caused by a translational movement transverse to an extent of the rotational axis;
• measuring errors that are not errors caused by the translational movement;
• and
• angular positions of the sensors about the rotational axis;
• and said evaluation device being further configured to determine the translational errors assigned to the respective sensor and the measuring errors from the calculation model and to correct the translational errors and the measuring errors of the measuring arrangement for the operation of the rotary device.