Method and apparatus for reduced temperature dependent position detection
US6541961B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 28, 2002 |
| Grant date | Apr 1, 2003 |
| Priority date | — |
| Expiry date | Jan 28, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B7/02
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The invention relates to a method for substantially temperature-independent detection of the position of a moving element (9) by way of an inductive position sensor (1), comprising a coil (5) and a core (4) movable within the coil, the position of said core in relation to the coil (5) being dependent on the position of said element (9), whereby a measurement of the inductance of said coil (5), corresponding to the core (4) position, is detected by connecting a voltage to said coil (5) and measuring the time period in which a current (i) through the coil (5) is changed between two predetermined levels. The method follows the steps of feeding a regularly alternating voltage to the coil (5), measuring the current (i) flowing through the coil (5), measuring the period of time (t1) needed for the current (i) to change from a first predetermined level (i1) to a second predetermined level (i2), and determining a measurement of the core (4) position through measuring the period of time (t1). Through the invention, an improved position detection is provided, primarily intended for automotive vehicle gearboxes, achieving a highly reduced temperature dependence.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.