Measuring probe with field generating coil configuration and temperature compensation

Patent metadata

Field	Value
Publication number	US-12320635-B2
Application number	US-202218147553-A
Country	US
Kind code	B2
Filing date	Dec 28, 2022
Priority date	Dec 28, 2022
Publication date	Jun 3, 2025
Grant date	Jun 3, 2025

Abstract

A measuring probe for a coordinate measuring machine is provided. The measuring probe includes a stylus position detection portion, signal processing and control circuitry and a temperature dependent compensation portion. The stylus position detection portion includes a field generating coil configuration and a sensing coil configuration. The temperature dependent compensation portion includes a temperature dependent component that is coupled to a field generating coil of the field generating coil configuration such that a change in a characteristic of the temperature dependent component due to an increase in temperature of the temperature dependent component causes relatively more current to flow through the field generating coil when driven by the coil drive signal than if the characteristic of the temperature dependent component had not changed. Such implementations are configured to increase the accuracy of the processed signals by at least partially compensating for certain affects that occur due to temperature changes.

First claim

What is claimed is:

1. A measuring probe for a coordinate measuring machine, the measuring probe comprising:
a stylus suspension portion, comprising:
a stylus coupling portion that is configured to be rigidly coupled to a stylus with a probe tip; and
a stylus motion mechanism that is configured to enable axial motion of the stylus coupling portion along an axial direction, and rotary motion of the stylus coupling portion about a rotation center;

a stylus position detection portion arranged along a central axis that is parallel to the axial direction and nominally aligned with the rotation center, comprising:
a field generating coil configuration comprising at least one field generating coil;
a sensing coil configuration, comprising:
top position sensing coils, comprising:
at least one top axial sensing coil;
at least four top rotary sensing coils;

at least one top normalization sensing coil;
bottom position sensing coils, comprising:
at least one bottom axial sensing coil;
at least four bottom rotary sensing coils; and

at least one bottom normalization sensing coil;

a disruptor configuration comprising a conductive disruptor element that provides a disruptor area, wherein the disruptor element is located along the central axis in a disruptor motion volume and the disruptor element is coupled to the stylus suspension portion, wherein the disruptor element moves in the disruptor motion volume relative to an undeflected position in response to a deflection of the stylus suspension portion, the field generating coil configuration generating a changing magnetic flux generally along the axial direction in the disruptor motion volume in response to a coil drive signal;
signal processing and control circuitry that is operably connected to the coils of the stylus position detection portion to provide the coil drive signal and configured to receive signals comprising respective signal components provided by the respective sensing coils, and provide signals indicative of an axial position and a rotary position of the probe tip; and:
a temperature dependent compensation portion comprising a temperature dependent component, wherein the temperature dependent component is coupled to a field generating coil of the field generating coil configuration such that a change in a characteristic of the temperature dependent component due to an increase in temperature of the temperature dependent component causes relatively more current to flow through the field generating coil when driven by the coil drive signal than if the characteristic of the temperature dependent component had not changed.

2. The measuring probe of claim 1 , wherein the temperature dependent component is a temperature dependent resistor and the characteristic that changes is the resistance of the temperature dependent resistor.

3. The measuring probe of claim 2 , wherein the temperature dependent resistor is a temperature coefficient resistor.

4. The measuring probe of claim 2 , wherein the temperature dependent resistor is a thermistor.

5. The measuring probe of claim 1 , wherein the temperature dependent component is one of coupled in parallel or coupled in series with the field generating coil.

6. The measuring probe of claim 1 , wherein the temperature dependent component is a positive temperature coefficient resistor for which the resistance increases as the temperature increases.

7. The measuring probe of claim 6 , wherein the positive temperature coefficient resistor is coupled in parallel with the field generating coil.

8. The measuring probe of claim 1 , wherein:
the field generating coil has first and second coil terminals; and
the measuring probe comprises a resonant circuit portion connected to the first and second coil terminals, the resonant circuit portion comprising at least a first resonant circuit portion component and a second resonant circuit portion component, wherein the first resonant circuit portion component is coupled between a first resonant circuit portion node and a second resonant circuit portion node, the first resonant circuit portion node is separated from the first coil terminal by at least the second resonant circuit portion component.

9. The measuring probe of claim 8 , wherein the resonant circuit portion further comprises a third resonant circuit portion component, wherein the second resonant circuit portion node is separated from the second coil terminal by at least the third resonant circuit portion component.

10. The measuring probe of claim 9 , wherein:
the first resonant circuit portion component comprises a first resonant circuit capacitor which is connected between the first and second resonant circuit portion nodes; and
the second resonant circuit portion component comprises a second resonant circuit capacitor which has a respective first terminal connected to the first resonant circuit portion node, and a respective second terminal connected to the first coil terminal; and
the third resonant circuit portion component comprises a third resonant circuit capacitor which has a respective first terminal connected to the second resonant circuit portion node, and a respective second terminal connected to the second coil terminal.

11. The measuring probe of claim 8 , further comprising an amplifier portion connected to the first and second resonant circuit portion circuit nodes, the amplifier portion having an output impedance during operation, wherein the amplifier portion is configured to provide an oscillating drive signal at the first and second resonant circuit portion nodes, the amplifier portion comprising first and second amplifier inputs and first and second amplifier outputs, with the first amplifier output connected to the first resonant circuit portion node and the second amplifier output connected to the second resonant circuit portion node.

12. The measuring probe of claim 11 , further comprising:
a first filter portion connected to the first coil terminal and the first amplifier input of the amplifier portion; and
a second filter portion connected to the second coil terminal and the second amplifier input of the amplifier portion.

13. The measuring probe of claim 12 , wherein:
the first filter portion comprises a first filter portion capacitor and a first filter portion resistor which are coupled in series between the first coil terminal and the first amplifier input; and
the second filter portion comprises a second filter portion capacitor and a second filter portion resistor which are coupled in series between the second coil terminal and the second amplifier input.

14. The measuring probe of claim 1 , wherein the signal processing and control circuitry is configured to divide signals from the axial and rotary sensing coils by signals from the normalization sensing coils to determine the signals that are indicative of an axial position and a rotary position of the probe tip.

15. A method of operating a measuring probe for a coordinate measuring machine,
the measuring probe comprising:
a stylus suspension portion, comprising:
a stylus coupling portion that is configured to be rigidly coupled to a stylus with a probe tip; and
a stylus motion mechanism that is configured to enable axial motion of the stylus coupling portion along an axial direction, and rotary motion of the stylus coupling portion about a rotation center;

a stylus position detection portion arranged along a central axis that is parallel to the axial direction and nominally aligned with the rotation center, comprising:
a field generating coil configuration comprising at least one field generating coil;
a sens

Assignees

• Mitutoyo Corp

Inventors

• Hamner Christopher Richard
• Harsila Scott Allen

Classifications

• G01B5/0014

  due to temperature (on machine tools B23Q11/0003) · CPC title

• G01B5/012 Primary

  Contact-making feeler heads therefor · CPC title

• G01B7/012 Primary

  Contact-making feeler heads therefor · CPC title

• G01B7/016 Primary

  Constructional details of contacts · CPC title