[go: up one dir, main page]

WO1987007010A1 - Procede et appareil de mesure precise d'un angle de torsion - Google Patents

Procede et appareil de mesure precise d'un angle de torsion Download PDF

Info

Publication number
WO1987007010A1
WO1987007010A1 PCT/SE1987/000229 SE8700229W WO8707010A1 WO 1987007010 A1 WO1987007010 A1 WO 1987007010A1 SE 8700229 W SE8700229 W SE 8700229W WO 8707010 A1 WO8707010 A1 WO 8707010A1
Authority
WO
WIPO (PCT)
Prior art keywords
signal
pulses
memory
rotational angle
period
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/SE1987/000229
Other languages
English (en)
Inventor
Kurt-Ove Stenberg
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ELOPTRICON AB
Original Assignee
ELOPTRICON AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ELOPTRICON AB filed Critical ELOPTRICON AB
Publication of WO1987007010A1 publication Critical patent/WO1987007010A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
    • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
    • G01D5/36—Forming the light into pulses

Definitions

  • the present invention relates to a method of accurately measuring an object that rotates around a first symmetry axis at a sub ⁇ stantially constant rotational speed, comprising the steps of:
  • a pulse emitting unit that is fixed in a defined rotational angle relationship to the object to emit a first signal S.. consisting of pulses at a first frequency f 1 that is dependent upon the rotation of the object;
  • a measuring signal transmitting unit causing a measuring signal transmitting unit to emit a third signal S, indicative of the respective instants of beginning and of ending of at least one rotational angle measurement during the rotation of the object.
  • the invention also relates to apparatus for carrying out such a method.
  • a relatively good accuracy in the measurement of a rotational angle can be obtained by this method, with a corre ⁇ sponding apparatus.
  • the difficulty lies in devising a pulse emit ⁇ ting unit that will emit pulses, each of which corresponds exact- ly to a like rotational angle magnitude, in practice on the order of 2 ⁇ x10 —4 radians or less per pulse.
  • the pulse emitting unit comprises a rotating plate with a transparent circular ring provided with a large number (on the order of 10,000) opaque radial lines, which are intended to be evenly distributed around the circular ring.
  • a radiation source for example for infra-red radiation, directs its radiation around the circle ring which, during rotation of the plate, produces pulses that are detected by a detector located at the other side of the circle ring, arranged to produce a signal consisting of corresponding pulses.
  • the problem is that it can be difficult to obtain an absolutely uniform division of the circle ring, so that the lengthhs of the pulses can vary somewhat.
  • This can be compensated for, in and of itself, by effecting a corresponding calibration, in which an object's rotational angle is measured with some reference method, for example by means of laser interference under static conditions.
  • This applies, however, only to the calibration of the rotational angle in relation to the number of whole pulses, or rather the corresponding whole periods. Every such period can be divided up according to a known method into a fixed number of im ⁇ pulses by means of an oscillator. But this method does not take into account the fact that those periods can differ somewhat in duration.
  • the object of the invention is to provide a method of the type mentioned in the introduction which is distinguished by especially great accuracy. According to the invention, such a method is characterized by, in a computer unit:
  • a calculating unit B 1 to calculate from M M.. j bb ++ MM 2 -bb/M 3 -bb -— f-.a — M ⁇ a/M,a a value V. related to the measured rotational angle.
  • the pulse emitter unit comprises
  • a radiation source so directing its radiation toward said circular ring that a detector instrumentality receives radia ⁇ tion pulses resulting from the radiation passing the circular ring, the detector instrumentality being so arranged as to convert these radiation pulses into said first signal S 1 .
  • Such a pulse emitting unit can be further improved by arranging a first and a second mirror instrumentality to return radiation that passes through said circular ring back through the same to meet said detector instrumentality.
  • the pulse period is thus re ⁇ pokerd to half, that is, the pulse frequency is doubled.
  • Fig. 1 is a schematic block diagram of an apparatus according to the invention:
  • Fig. 2 is a diagram of the relationship between amplitude and time for the signals S 1 , S_ and S,;
  • Fig. 3 is a schematic block diagram of a calculator unit accord ⁇ ing to the invention.
  • Fig. 4 schematically shows a part of a pulse emitting unit ac- cording to the invention, seen from above;
  • Fig. 5 shows the same unit as Fig. 4, but as seen from the side.
  • a rotating object 1 is coupled by means of a shaft 2 to a pulse emitting unit 3.
  • a pulse emitting unit 3 This involves 5 that the latter stand in a defined rotational angle relationship to the object and generate pulses with a first frequency f_. in dependence upon the rotation of the object, which are emitted in the form of a first signal S_, that is preferably converted to a square-wave pulse train.
  • An. oscillator 4 generates pulses at a frequency f which is sub ⁇ stantially larger than f.. and emits these in the form of a second signal S ? , preferably in the form of a square-wave pulse train.
  • a measuring signal transmitting unit 5 finds the position of rotation of the object, for example by optical means, and pro- 15 Jerusalem notices a third signal S, indicating the instants of beginning and of ending of a rotational angle measurement.
  • a computer unit 6 which comprises a first and a second counter R 1 and R ? , a first, second and third memory M. , M_ and M.,, together with a cal- 20 ' . culating unit B 1 , as can be seen in Fig. 3.
  • the first counter R 1 is arranged to count the pulses of the first signal, that is, the period of each revolution of rotation of the object 1.
  • the second counter R- is arranged to count the pulses of the second signal SRON for every period in the first signal S 1 .
  • a calculator unit B 1 calculates with the aid of
  • the measuring method will be more clearly understood from Fig. 2.
  • the signal S. is shown for two whole periods, n + 1 and n + 2. It will be understood that the latter period is somewhat longer than the first, so that the period n + 1 corresponds to 8 periods of the signal S 9 and the period n + 2 corresponds to 9 periods of the signal S_.
  • a first impulse (a) is obtained from the measuring signal trans ⁇ mitter unit at instant t 1 .
  • M.a n
  • From R consult the total number of S ? pulses is trans- ferred to M consult, so that M_a 3.
  • V. related to the measured angle of rotation, obtained with the aid of the calculator unit
  • the units are obviously the periods in the signal S... This depends upon the design of the pulse emitting unit.
  • Figs. 4 and 5 show a preferred embodiment of such a pulse emitting unit.
  • a circular disc 7 is rotatable about a shaft 2 which in this case is directly connected with a rotating object 1. It should be ob- served that the rotational angle relationship between a rotating object and the pulse emitting unit can be of many different types. Thus, more or less sophisticated optical designs can be found, according to the degree of precision desired.
  • the circular disc 7 is made with a transparent circular ring 8 at its periphery that is provided with a large number of opaque radial surface elements, that is, lines 9, of which only a few have been indi ⁇ cated in Fig. 4.
  • a radiation source 10 directs its radiation, which can, for example, lie in the infra-red region, at right 1 angles ⁇ through the circular ring 8.
  • the pulsing radiation that passes the circular ring is reflected back by first and second mirror instrumentalities 11a, 11b through another part of the circular ring and reaches a detector that comprises a pulse emit ⁇ ting unit. . From the latter there is thus given off a signal S 1 .
  • the radiation that reaches the detector appears in approximately sine wave form, and with the aid of electronic means the signal S. emitted from the pulse emitting unit to the calculator unit 6 is converted to a square wave with many short rise and fall periods.
  • the signal S. will in this manner take the form that is _ shown in Figs. 1 and 2.
  • the frequency of the signal S obviously depends upon the rate of rotation of the disc 7 and the number of divisions, that is, the number- of radial surface elements in its circular ring 8. If the n rate of rotation is, for example, 10 revolutions/second and there are 10 divisions, the frequency in that case will be
  • the process according to the invention is applicable in situa ⁇ tions where an accurate measuring of the angle of rotation of a rotating object is required.
  • This process relates particularly to accurate measuring of shafts with finished bearing surfaces, such as crankshafts for vehicle engines.
  • a corresponding apparatus the position of a laser beam in a measuring plane is measured by means of an optical system that comprises a polygonal mirror fixedly coupled to a pulse emitting unit of the type that is described in the present patent appli ⁇ cation.
  • the angular position of the machine part in that case the crankshaft — is determined with the use of a process and an apparatus according to the present invention, which is obviously applicable in numerous fields of measuring tech ⁇ nology.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optical Transform (AREA)
  • Length Measuring Devices With Unspecified Measuring Means (AREA)
  • Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
  • Transmission And Conversion Of Sensor Element Output (AREA)

Abstract

Un procédé de mesurage précis de l'angle de rotation d'un objet qui tourne comprend les étapes de procédure suivantes: une unité émettrice d'impulsions (3) produit un signal (S1) composé d'impulsions à une fréquence f1 dépendant de la rotation de l'objet, un oscillateur (4) émet un signal S2 composé d'impulsions à une fréquence f2 sensiblement plus élevée que f1 et une unité émettrice de signaux de mesure (5) produit un signal S3 indiquant les moments où commence et finit respectivement la mesure de l'angle de rotation. Selon la présente invention, un compteur (R1) disposé dans une unité calculatrice compte les impulsions du siganl S1, c'est-à-dire les périodes de chaque révolution de l'objet, un compteur (R2) compte les impulsions du signal S2 pour chaque période dans le signal S1. Lors d'une première et d'une seconde impulsions respectivement du signal S3, une première mémoire (M1) enregistre le nombre d'impulsions de S1 = M1a et M1b, respectivement, une seconde mémoire (M2) enregistre la somme des impulsions de S2, M2a et M2b, respectivement alors qu'une troisième mémoire (M3), à la fin de la première période de S1 après les première et seconde impulsions respectives de S3 enregistre la somme des impulsions de S2 durant une période de S1 = M3a et M3b, respectivement, une unité calculatrice B1 calculant une valeur V1 correspondant à l'angle de rotation mesuré sur la base de M1b + M2b/M3b - M1a - M2a/M3a.
PCT/SE1987/000229 1986-05-09 1987-05-07 Procede et appareil de mesure precise d'un angle de torsion Ceased WO1987007010A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8602111A SE453225B (sv) 1986-05-09 1986-05-09 Forfarande och anordning for noggrann metning av en vridningsvinkel
SE8602111-0 1986-05-09

Publications (1)

Publication Number Publication Date
WO1987007010A1 true WO1987007010A1 (fr) 1987-11-19

Family

ID=20364468

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1987/000229 Ceased WO1987007010A1 (fr) 1986-05-09 1987-05-07 Procede et appareil de mesure precise d'un angle de torsion

Country Status (5)

Country Link
EP (1) EP0412960A1 (fr)
JP (1) JPH01502359A (fr)
AU (1) AU7359387A (fr)
SE (1) SE453225B (fr)
WO (1) WO1987007010A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000031498A1 (fr) * 1998-11-24 2000-06-02 Hamamatsu Photonics K.K. Unite de projection/reception et dispositif de recherche d'une plage omnidirectionnelle

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
No relevant documents have been disclosed. *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000031498A1 (fr) * 1998-11-24 2000-06-02 Hamamatsu Photonics K.K. Unite de projection/reception et dispositif de recherche d'une plage omnidirectionnelle
US6411374B2 (en) 1998-11-24 2002-06-25 Hamamatsu Photonics K.K. Light-projecting/receiving unit and omnidirectional distance detecting apparatus

Also Published As

Publication number Publication date
JPH01502359A (ja) 1989-08-17
SE453225B (sv) 1988-01-18
SE8602111L (sv) 1987-11-10
AU7359387A (en) 1987-12-01
SE8602111D0 (sv) 1986-05-09
EP0412960A1 (fr) 1991-02-20

Similar Documents

Publication Publication Date Title
US4297030A (en) Method and apparatus for measuring the distance and/or relative elevation between two points
US6304825B1 (en) Rotary encoder error compensation system and method for photoreceptor surface motion sensing and control
US4240069A (en) Angle coder with variable input angle
US4622462A (en) Method and apparatus for three-dimensional scanning
US3800423A (en) Method and apparatus for measuring pitch or indexing errors in toothed members
US5329814A (en) Apparatus for turning a body to be balanced into a working position
GB2285137A (en) Method and apparatus for measuring rotary movement of a shaft
JP2549280B2 (ja) ロ−タリ−エンコ−ダ
CN106525302A (zh) 一种基于高精度键相的旋转轴扭矩非接触动态测量系统
US4716292A (en) Linear incremental measuring system for measuring speed and displacement
US5293040A (en) Method and apparatus for measuring vibrations of rotating shaft
US4521113A (en) Optical measuring device
WO1987007010A1 (fr) Procede et appareil de mesure precise d'un angle de torsion
US4947695A (en) Apparatus for controlling a star wheel for positioning specimen containers
CA1114203A (fr) Systeme d'affichage pour equilibreuse de roues
GB1592514A (en) Distance measuring apparatus
US3867629A (en) System for measuring rotation using polarized light
JP6640541B2 (ja) レーザスキャナ
US3536406A (en) Digital angle measuring apparatus
US3833808A (en) Deflection angle measuring apparatus and method
Ivanov Experience of Developing and Investigating Circular Angle Measuring Transducers of High Resolving Power
RU4606U1 (ru) Цифровой измеритель мощности, крутящего момента и частоты вращения
US5048338A (en) Electronic bobweight eliminator
JPS62255807A (ja) 膜厚測定装置
SU1767325A1 (ru) Способ контрол угла поворота

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AU JP KR US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): CH DE FR GB IT

WWE Wipo information: entry into national phase

Ref document number: 1987902858

Country of ref document: EP

WWP Wipo information: published in national office

Ref document number: 1987902858

Country of ref document: EP

WWW Wipo information: withdrawn in national office

Ref document number: 1987902858

Country of ref document: EP