US 10,473,536 B2Granted

Gap compensation for magnetostrictive torque sensors

AssigneeBently Nevada, LLC

InventorsDan Tho Lu, Brian F. Howard, Pekka Tapani Sipila

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Abstract

A gap compensated torque sensing system and methods for using the same are provided. The system can include a sensor head in communication with a controller. The sensor head can contain a torque sensor and a proximity sensor coupled to the sensor head. The torque and proximity sensors can each sense magnetic fluxes passing through the target and a gap between the sensor head and the target. The controller can estimate torque applied to the target from magnetic fluxes sensed by the torque sensor. The controller can determine an improved gap measurement that is independent of electromagnetic properties of the target from magnetic fluxes sensed by the torque and proximity sensors. The estimated torque can be modified by the improved gap measurement to compensate for changes in magnetic properties of the target due to variations in the gap. In this manner, the accuracy of the torque measurements can be increased.

Claims16

Dependent claims

A magnetostrictive sensor, comprising:

a sensor head including,
a driving pole having a driving coil coupled thereto that is configured to generate magnetic fluxes in response to a driving current;
two magnetic sensors coupled to respective sensing poles and each configured to output a first signal based at least upon first magnetic fluxes and second magnetic fluxes sensed by the two magnetic sensors, the first sensed magnetic fluxes resulting from interaction of the generated magnetic fluxes with a target, a gap between the sensor head and the target and the second sensed magnetic fluxes resulting from interaction of the generated magnetic fluxes with the gap;
and
a proximity coil coupled to the driving pole that is configured to output a second signal based at least upon the first magnetic fluxes, the second magnetic fluxes, and third magnetic fluxes sensed by the proximity coil, the third magnetic fluxes resulting from interaction of the generated magnetic fluxes with the gap;
and
a controller in electrical communication with the sensor head, the controller configured to,
receive the first signals and the second signal,
determine a third signal based upon the first signals and the second signal, wherein the third signal is a function of the gap, and
determine a force applied to the target based upon the first signals and the third signal.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/675,269Filed 11 Aug 2017
Published: US 2019/0049320 A114 Feb 2019
Granted: 12 Nov 2019
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

G01L 1/125
By measuring variations in the magnetic properties of materials resulting from the application of stress: by using magnetostrictive means
G01B 7/14
Measuring arrangements characterised by the use of electric or magnetic techniques: for measuring distance or clearance between spaced objects or…
G01D 3/0365
On measuring arrangements themselves: the undesired influence being measured using a separate sensor, which produces an influence related signal
G01L 3/102
Involving magnetic or electromagnetic means: involving magnetostrictive means