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ACTIVE POSITIONING OF TORQUE SENSOR

IP.com Disclosure Number: IPCOM000242508D
Publication Date: 2015-Jul-21
Document File: 4 page(s) / 59K

Publishing Venue

The IP.com Prior Art Database

Abstract

The present invention provides a technique for decimating torque signal from orientation error signal. The technique includes either applying a known actuation or setting a system into a known position every time to overcome decimation of torque signal. The technique uses a non-torque sensitive signal to control positioning of the system. Once actuation and its influence to signal is known, the technique determines operating point of a sensor. The operating point is defined on a probe orientation to a target, as well as by diameter of shaft geometry. In order to discriminate change in eddy current response, the technique uses eddy current response to monitor sensor orientation and further use the orientation information to correct the signal, or to readjust positioning of sensor. Multiple AC signals of the sensor are also utilized in parallel for better discrimination of the location.

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ACTIVE POSITIONING OF TORQUE SENSOR

BACKGROUND

The present invention relates generally to non-contacting torque sensors and more particularly to a technique for active positioning of torque sensors.

Variation in relative positioning between target and sensor deteriorates signal quality of a non-contacting, magnetostriction-based torque sensor. Variations in the positioning are due to thermal expansion in the bearings, shaft and drive train vibration, sensor and bracket vibration, installation errors and shaft relative movement during start-up and shut down, for example, during rising up of shaft on oil film, among others.

For example, a conventional technique includes location of piezoelectric actuators and sensors for active control of flexible structures. Another conventional technique includes method and system for locating position of a source that emits a rotating magnetic field. Three or more receivers are deployed or positioned in known position relative to each other. The receivers are positioned such that they are along a common axis in certain instants.

One other conventional technique includes a device for positioning object in nanometer (nm) range using piezoelectric actuator. However, such conventional techniques provide complex and non-linear response which creates difficulty in suppressing effect of the positioning error.

It would be desirable to have a technique to provide active positioning of non-contacting torque sensors to improve insensitivity to gap and orientation variations.

DETAILED DESCRIPTION

The present invention provides a technique for decimating torque signal from orientation error signal. The technique includes either applying a known actuation or setting a system into a known position every time to overcome decimation of torque signal. The technique uses a non-torque sensitive signal to control positioning of the system.

 

Once actuation and its influence to signal is known, the technique determines operating point of a sensor. The operating point is defined on a probe orientation to a target, as well as by diameter of shaft geometry.

Torque or stress change is provided by permeability change of medium. The torque provides eddy current change in a target. As a result, there is phase shift in the target. By knowing that the torque results in eddy current change the technique discriminates torque by comparing on variation of air gap, which is a non-dispersive medium.

Actuators, generally, belong to three categories. For example, the actuators are piezoelectric actuators, magnetostrictive actuators and electromotor actuators. The technique includes any of the three types of actuators.

The technique uses motor movement either directly or transformed between linear and rotational movement. Motor movement is along plurality of axis and rotations. It is required that motor movement is along every axis to which the sensor is sensitive.

Applied motor movement is at an alternating current (AC) frequency or at a direct...