US 2019/0195660 A1Published application

High resolution absolute encoder

AssigneeServosense (SMC) Ltd.

InventorsYves Villaret, Alexander Puzev

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Abstract

A high resolution encoder device using a number of static sensors distributed on a circumference, and a rotating disc, having several sections of two different properties on an annular track according to a predefined pattern, placed so that the sensors can sense the properties of the sections of track in proximity. An auxiliary unit is also provided and by itself or in combination with the sensor signal values, provides a first low resolution position value. In a first processing step, the signals of each sensor are compared to a threshold, and bit values zero or one for each sensor are set according to the comparison result. All bits are then set in a digital word, in order to create a code number, which in combination with the output of the auxiliary unit, is characteristic of a first low resolution position value. For each low resolution position value, a mathematical combination of signals values is defined. The values of the result of said mathematical combination of the signals value is then used as an entry variable to pre-recorded tables to output high resolution position value.

Claims10

Dependent claims

A high resolution encoder device to measure the angular position of a rotating element, comprising:

a) first means to provide a first angular position value;
b) a rotating disc fixed to the rotating element, said rotating disc including a circular track having sections associated with a first and second property according to a given pattern,
c) a number of fixed sensors positioned in proximity of said circular track, each sensor outputting an electrical signal having a first range of analog values when in proximity to said circular track section associated with said first property, and a second range of analog values when in proximity to said circular track section associated with said second property,
each sensor receiving continuously changing intermediate values when said rotating disc rotates from a position at which said sensor is in proximity to said circular track section associated with said first or second property to a position at which said sensor is in proximity to said circular track section associated with said second or first property respectively,
d) processing means to process the analog values of said electrical signals;
and
e) a memory to store pre-recorded tables of signal selection, signal combinations and table position values,
wherein for every said first angular position value there is selected:
i) a number of said electrical signals,
ii) at least one mathematical combination of analog values of said selected electrical signals and
iii) at least one of said pre-recorded table position values,
wherein said selected electrical signal analog values are combined using said selected mathematical combination to provide a combined value, and
wherein at least one high resolution angular position value of said rotating disc is retrieved from at least one of said selected table position values using said combined analog value as an entry variable.

10 more elements

A method for measuring the angular position of a rotating element, using a high resolution encoder device comprising:

providing a high resolution encoder device comprising:
a) first means to provide a first angular position value;
b) a rotating disc fixed to the rotating element, said rotating disc including a circular track having sections associated with a first and second property according to a given pattern,
c) a number of fixed sensors positioned in proximity of said circular track, each sensor outputting an electrical signal having a first range of analog values when in proximity to said circular track section associated with said first property, and a second range of analog values when in proximity to said circular track section associated with said second property,
each sensor receiving continuously changing intermediate values when said rotating disc rotates from a position at which said sensor is in proximity to said circular track section associated with said first or second property to a position at which said sensor is in proximity to said circular track section associated with said second or first property respectively,
d) processing means to process the analog values of said electrical signals;
and
e) a memory to store pre-recorded tables of signal selection, signal combinations and table position values,
and selecting, for every said first angular position value:
i) a number of electrical signals;
ii) at least one mathematical combination of analog values of said selected electrical signals and
iii) at least one of said pre-recorded table position values,
wherein said selected electrical signal analog values are combined using said selected mathematical combination to provide a combined value, and
wherein at least one high resolution angular position value of said rotating disc is retrieved from at least one of said selected table position values using said combined value as an entry variable.

11 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/328,732Filed 31 Jul 2017
Priority: 2 Aug 2016
Published: 27 Jun 2019
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

G01D 5/2497
Using pulse code: absolute encoders
G01D 5/145
Using Hall-effect devices: influenced by the relative movement between the Hall device and magnetic fields
G01D 5/24476
Error correction: signal processing
H03M 7/16
Conversion to or from non-weighted codes: conversion to or from unit-distance codes, e.g. Gray code, reflected binary code