Motion detecting apparatus

Patent metadata

Field	Value
Publication number	US-10697803-B2
Application number	US-201515315793-A
Country	US
Kind code	B2
Filing date	Jun 5, 2015
Priority date	Jun 30, 2014
Publication date	Jun 30, 2020
Grant date	Jun 30, 2020

Abstract

To reduce information used for processes of complementing a missing detection pulse of a magnetic field detecting section, the apparatus carries out the processes of storing, as rotation direction information of a movable section 43, “rightward direction”, “leftward direction”, “unidentified” and “unidentified inversion”, and setting the rotation direction information to “unidentified” when recognizing a missing detection pulse, and subsequently, adjusting a rotation change amount of the movable section using a first adjustment value if the rotation direction information becomes the “unidentified” and adjusting the rotation change amount of the movable section using a second adjustment value if the rotation direction information is updated from the “unidentified” to the “rightward direction” or the “leftward direction”.

First claim

The invention claimed is:

1. A motion detecting apparatus for detecting rotating motion of a detected object, comprising:
a movable section fixed to the detected object and rotating according to the rotating motion of the detected object;
at least one pair of magnets located in the movable section to respectively generate magnetic fields in different directions from each other;
n magnetic sensors, wherein n is an integer 3 or more, located in a vicinity of the movable section, wherein any one of the n magnetic sensors changes a magnetization direction thereof and outputs a positive detection pulse when one of said at least one pair of magnets approaches said any one of the n magnetic sensors, and said any one of the n magnetic sensors changes the magnetization direction thereof and outputs a negative detection pulse when another of said at least one pair of magnets approaches said any one of the n magnetic sensors; and
a motion detecting circuit having a storage section, receiving detection pulses outputted from the n magnetic sensors, and detecting a state of the rotating motion of the detected object on a basis of the received detection pulses,
wherein said at least one pair of magnets and the n magnetic sensors are located so that detection pulses in respective one of a positive direction and a negative direction are continuously outputted one by one at different timings from the respective n magnetic sensors while the movable section rotates in one direction, and subsequently, detection pulses in respective another of the positive direction and the negative direction are continuously outputted one by one at different timings from the respective n magnetic sensors while the movable section further rotates in said one direction, and thereby, a constant output pattern composed of 2n detection pulses is formed, wherein each one of the 2n detection pulses composing the output pattern is different from any other of the 2n detection pulses composing the output pattern with respect to a direction of a detection pulse, a magnetic sensor from which the detection pulse is outputted, or both the direction of the detection pulse and the magnetic sensor from which the detection pulse is outputted,
wherein the motion detecting circuit assigns numbers of 1, 2, . . . , n, n+1, n+2, . . . , 2n to the 2n detection pulses composing the output pattern in order of outputs of the 2n detection pulses while the movable section rotates said one direction,
wherein the storage section stores a number of a last detection pulse outputted from any one of the n magnetic sensors, motion direction information indicating that a motion direction of the movable section at a time when the last detection pulse is outputted is said one direction, another direction, an unidentified state, or an unidentified inversion state, wherein the unidentified inversion state is an inversion in the unidentified state, and a motion amount detection value indicating a motion amount of the movable section at the time when the last detection pulse is outputted,
wherein the motion detecting circuit decides whether the motion direction of the movable section at a time when a present detection pulse is outputted from any one of the n magnetic sensors is said one direction, said another direction, the unidentified state or the unidentified inversion state, and decides or sets the motion amount of the movable section at the time when the present detection pulse is outputted on a basis of (i) a difference between a number of the present detection pulse and the number of the last detection pulse, (ii) the motion direction information, and (iii) the motion amount detection value, and
wherein the motion detecting circuit updates the number of the last detection pulse stored in the storage section on a basis of the number of the present detection pulse, updates the motion direction information stored in the storage section on a basis of a decision with respect to the motion direction of the movable section at the time when the present detection pulse is outputted, and updates the motion amount detection value stored in the storage section on a basis of a decision or setting with respect to the motion amount of the movable section at the time when the present detection pulse is outputted.

2. The motion detecting apparatus according to claim 1 , wherein:
the motion detecting circuit calculates a comparison value by subtracting the number of the last detection pulse from the number of the present detection pulse, wherein, if a value obtained by subtracting the number of the last detection pulse from the number of the present detection pulse is a negative value, a value is taken by adding 2n to the obtained value as the comparison value,
decides, if the comparison value is 1 and the motion direction information indicates said one direction, that the motion direction of the movable section at the time when the present detection pulse is outputted is said one direction, and a change value of the motion amount of the movable section at the time when the present detection pulse is outputted is +1,
decides, if the comparison value is 2n−1 and the motion direction information indicates said another direction, that the motion direction of the movable section at the time when the present detection pulse is outputted is said another direction, and the change value of the motion amount of the movable section at the time when the present detection pulse is outputted is −1,
decides, if the comparison value is n and the motion direction information indicates said one direction, that the motion direction of the movable section at the time when the present detection pulse is outputted is said another direction, and the change value of the motion amount of the movable section at the time when the present detection pulse is outputted is −n,
decides, if the comparison value is n and the motion direction information indicates said another direction, that the motion direction of the movable section at the time when the present detection pulse is outputted is said one direction, and the change value of the motion amount of the movable section at the time when the present detection pulse is outputted is +n,
decides, if the comparison value is 2 and the motion direction information indicates said one direction, that the motion direction of the movable section at the time when the present detection pulse is outputted is the unidentified state, and sets the change value of the motion amount of the movable section at the time when the present detection pulse is outputted to −(n−1)/2,
decides, if the comparison value is n−1 and the motion direction information indicates said one direction, that the motion direction of the movable section at the time when the present detection pulse is outputted is the unidentified state, and sets the change value of the motion amount of the movable section at the time when the present detection pulse is outputted to −(n−1)/2,
decides, if the comparison value is 2n−2 and the motion direction information indicates said another direction, that the motion direction of the movable section at the time when the present detection pulse is outputted is the unidentified state, and sets the change value of the motion amount of the movable section at the time when the present detection pulse is outputted to (n−1)/2,
decides, if the comparison value is n+1 and the motion direction information indicates said another direction, that the motion direction of the movable section at the time when the present detection pulse is outputted is the unidentified state, and sets the change value of the motion amount of the movable section at the time when the present detection pulse is outputted to (n−1)/2,
decides, if the comparison value is 1 and the motion direction information indicates the unidentified state, that the motion direction of the movable sectio

Assignees

• Hirose Electric Co Ltd

Inventors

• Kasuga Atsushi

Classifications

• G01D5/24495 Primary

  using previous values · CPC title

• G01D5/245 Primary

  using a variable number of pulses in a train · CPC title