JPH07198420A - Absolute encoder - Google Patents
Absolute encoderInfo
- Publication number
- JPH07198420A JPH07198420A JP33571393A JP33571393A JPH07198420A JP H07198420 A JPH07198420 A JP H07198420A JP 33571393 A JP33571393 A JP 33571393A JP 33571393 A JP33571393 A JP 33571393A JP H07198420 A JPH07198420 A JP H07198420A
- Authority
- JP
- Japan
- Prior art keywords
- code
- detection
- code word
- circular
- codes
- 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.)
- Granted
Links
- 238000001514 detection method Methods 0.000 claims description 53
- 239000011295 pitch Substances 0.000 claims description 4
- 238000005259 measurement Methods 0.000 abstract description 3
- 238000000034 method Methods 0.000 description 15
- 125000004122 cyclic group Chemical group 0.000 description 4
- 102100027340 Slit homolog 2 protein Human genes 0.000 description 2
- 101710133576 Slit homolog 2 protein Proteins 0.000 description 2
- 239000000428 dust Substances 0.000 description 2
- 101700004678 SLIT3 Proteins 0.000 description 1
- 102100027339 Slit homolog 3 protein Human genes 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
Landscapes
- Transmission And Conversion Of Sensor Element Output (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は測量等に用いられるアブ
ソリュートエンコーダーに関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absolute encoder used for surveying and the like.
【０００２】[0002]
【従来の技術】従来、この種のアブソリュートエンコー
ダーとして、０又は１を示す幅狭又は幅広のスリットか
ら成る物理的符号を同一円形トラックに等ピッチで、且
つ、該トラック上の各位置から連続してｎ個の物理的符
号をとって成る符号語が相互に異なる、即ち各符号語相
互のハミング距離が１以上となる様に配置した円形符号
板を用い、該符号板に対し相対回転する極座標の所定の
角度区域に存する連続したｎ個の物理的符号から成る符
号語をイメージセンサ等から成る検出手段で読み取っ
て、読み取られた符号語に対応する絶対角度位置を対応
表と照合して算定するようにしたものが知られている。2. Description of the Related Art Conventionally, as an absolute encoder of this type, a physical code composed of a narrow or wide slit indicating 0 or 1 is continuously arranged on the same circular track at an equal pitch and from each position on the track. Polar code that is rotated relative to the code plates by using the circular code plates arranged such that the code words formed by taking n physical codes are different from each other, that is, the Hamming distance between the code words is 1 or more. , A code word consisting of consecutive n physical codes existing in a predetermined angle area is read by a detecting means such as an image sensor, and the absolute angle position corresponding to the read code word is collated with a correspondence table to calculate. It is known to do so.
【０００３】この様な同一円形トラック上の物理的符号
列から成る数列を有する円形符号板を用いたアブソリュ
ートエンコーダーの方式は、シリアルコード読み取り方
式と呼ばれ、複数の数列を同心円状に設けるマルチトラ
ック方式に比べて、単一トラックで位置決めが行えるた
め、トラック間の位置関係の調節が不要、符号板の径を
小さくできること等、利点が多いとされてきた。An absolute encoder system using a circular code plate having several sequences of physical code sequences on the same circular track is called a serial code reading system, and a multi-track system in which a plurality of several sequences are concentrically provided. Compared with the method, it is said that positioning can be performed by a single track, so that it is not necessary to adjust the positional relationship between the tracks and the diameter of the code plate can be reduced, which has many advantages.
【０００４】しかしながら、シリアルコード方式のアブ
ソリュートエンコーダーにおいて、高精度で位置決めを
行おうとした場合には、数列の項数を大きくしなければ
ならず、そのため物理的符号であるスリットのパターン
を微細化しなければならなくなる。かかる微細化に伴
い、Ｓ／Ｎ比の低下やスリット上にゴミが付着する等に
よって読み取りミスが発生してしまうことがあった。こ
の様な読み取りミスは測定位置の検出ミスとなるので、
読み取りミス検出手段、訂正手段が必要とされてきた。However, in order to perform positioning with high accuracy in the serial code absolute encoder, the number of terms in the sequence must be increased, and therefore the slit pattern, which is the physical code, must be miniaturized. I will have to do it. With such miniaturization, a read error may occur due to a decrease in S / N ratio, dust attached on the slit, or the like. Since such a reading error is a detection error of the measurement position,
Read error detection means and correction means have been required.
【０００５】そこで従来は上記した角度区域に設ける第
１の検出手段に対し１８０°異なる位置に第２の検出手
段を設け、第２の検出手段で読み取られた符号語に対応
する絶対角度位置も対応表と照合して算定し、第１の検
出手段で読み取られた符号語に対応する絶対角度位置と
の角度差を求め、この角度差が１８０°になっているか
否かで読み取りミスの有無を判別するようにしていた。Therefore, conventionally, the second detecting means is provided at a position different by 180 ° from the first detecting means provided in the above-mentioned angular area, and the absolute angular position corresponding to the code word read by the second detecting means is also provided. It is calculated by collating with the correspondence table, the angular difference from the absolute angular position corresponding to the code word read by the first detecting means is determined, and whether or not there is a reading error depending on whether this angular difference is 180 ° or not. I was trying to determine.
【０００６】[0006]
【発明が解決しようとする課題】しかし上記の方法で
は、読み取りミスの判別のために、２つの検出手段で読
み取られた２つの符号語について各々絶対角度位置を対
応表で検索する必要があり、その処理に時間がかかって
迅速な作業の妨げとなっていた。本発明はこの様な不都
合を解消するために創作されたもので、その目的は読み
取りミスを短時間で発見することができ、且つ短い検索
時間で測定を可能ならしめるアブソリュートエンコーダ
ーを提供することにある。However, in the above method, it is necessary to search the correspondence table for the absolute angular positions of the two code words read by the two detecting means in order to determine a reading error. The processing takes time and hinders quick work. The present invention was created in order to eliminate such inconvenience, and an object thereof is to provide an absolute encoder capable of detecting a reading error in a short time and enabling measurement in a short search time. is there.
【０００７】[0007]
【課題を解決するための手段】上記課題を解決するため
に、本発明は、円形符号板であって、０又は１を示す物
理的符号が等ピッチで同一円形トラックに、且つ、該ト
ラックの各位置から連続してｎ個の物理的符号をとって
成る符号語と他の位置から連続してｎ個をとって成る符
号語とのハミング距離が１以上となる様に配置されたも
のと、前記円形符号板に対し相対回転する極座標の所定
の角度区域にある連続したｎ個の物理的符号から成る符
号語を読み取って第１検出符号を出力する第１検出手段
と、連続したｎ個の物理的符号から成る符号語と円形符
号板中の位置とを対応させた対応表を予め記憶しておく
記憶手段と、前記第１検出符号と前記対応表とから第１
検出手段の絶対角度位置を算出する算出手段とを備えた
アブソリュートエンコーダーにおいて、前記円形符号板
中の物理的符号は、連続したｎ個の物理的符号をとって
成る符号語と、該符号語とは１８０°対向する位置にあ
るｎ個の物理的符号から成る符号語とのハミング距離が
ｎである様に配置され、第１検出手段が読み取る符号語
とは１８０°対向した位置にある符号語を読み取って第
２検出符号を出力する第２検出手段と、第１検出符号と
第２検出符号とを比較して検出ミスの有無を判別する判
別手段とを備えたことを特徴とする。In order to solve the above-mentioned problems, the present invention is a circular code plate, in which the physical code indicating 0 or 1 is at the same circular track at equal pitches, and It is arranged such that the Hamming distance between a codeword that continuously takes n physical codes from each position and a codeword that continuously takes n from other positions is 1 or more. A first detection means for reading a code word consisting of consecutive n physical codes in a predetermined angular area of polar coordinates rotating relative to the circular code plate and outputting a first detection code; From the first detection code and the correspondence table, and a storage unit that stores in advance a correspondence table that associates a code word composed of the physical code of the above with a position in the circular code plate.
In an absolute encoder provided with a calculating means for calculating the absolute angular position of the detecting means, the physical code in the circular code plate is a code word formed by taking consecutive n physical codes, and the code word. Are arranged so that the hamming distance is n with respect to the code word consisting of n physical codes located 180 ° opposite to each other, and the code word is located 180 ° opposite to the code word read by the first detecting means. And a second detecting means for reading the second detecting code and outputting the second detecting code, and a judging means for comparing the first detecting code and the second detecting code to judge the presence or absence of a detection error.
【０００８】[0008]
【作用】第１検出手段が読み取るべき円形符号板中の符
号語と第２検出手段が読み取るべき符号語とは、ハミン
グ距離が符号語長ｎとなるように配置されているため、
２つの検出手段が読み込んだ検出符号同士を比較すれば
読み取りミスの有無を判別することができる。The code word in the circular code plate to be read by the first detecting means and the code word to be read by the second detecting means are arranged so that the Hamming distance becomes the code word length n.
Whether or not there is a reading error can be determined by comparing the detection codes read by the two detecting means.
【０００９】又、第１検出符号を対応表中の符号語と照
合して絶対角度位置を求める際、検出符号と対応表中の
符号語とのハミング距離が０であるものがあればその符
号語に対応する絶対角度位置が検出手段の絶対角度位
置、ハミング距離が符号語長ｎであるものがあればその
符号語に対応する絶対角度位置に１８０°加えた値が検
出手段の絶対角度位置であるとすることができる。従っ
て、検出符号を対応表と照合する際、最大でも対応表中
の符号語の半分と照合すれば、検出手段の絶対角度位置
を算出することができることとなる。Further, when the first detection code is collated with the code word in the correspondence table to obtain the absolute angular position, if the Hamming distance between the detection code and the code word in the correspondence table is 0, that code is present. If the absolute angular position corresponding to the word is the absolute angular position of the detecting means and the Hamming distance is the code word length n, a value obtained by adding 180 ° to the absolute angular position corresponding to the code word is the absolute angular position of the detecting means. Can be Therefore, when the detection code is collated with the correspondence table, the absolute angular position of the detection means can be calculated by collating with at most half of the code words in the correspondence table.
【００１０】更に、円形符号板にある符号語の全てを絶
対角度位置と対応させて対応表に記憶させる必要がな
く、１８０°対向する位置にあるいずれか一方の符号語
のみを円形符号板の絶対角度位置と対応させて記憶して
おけばよく、このため記憶容量が半分で済む。Further, it is not necessary to store all of the code words on the circular code plate in the correspondence table in association with the absolute angular position, and only one of the code words facing each other by 180 ° is stored on the circular code plate. It suffices to store it in association with the absolute angular position, and therefore the storage capacity is half.
【００１１】[0011]
【実施例】図１を参照して、１は円形符号板であり、周
方向に並べて０又は１を示す物理的符号であるスリット
２が刻まれている。スリット２は、図２に示す如く細い
ものと太いものとがあり、細いスリット２ａは０を表
し、太いスリット２ｂは１を表す。これらスリット２
ａ、２ｂは等ピッチＰで同一円形トラックＴ上に周方向
に配置してある。スリット２は、該トラック上の各位置
から連続してｎ個のスリットをとって成る符号語と他の
位置から連続してｎ個のスリットをとって成る符号語と
のハミング距離が１以上であり、且つ、連続したｎ個の
スリットをとって成る符号語と、該符号語とは１８０°
対向する位置にあるｎ個のスリットから成る符号語との
ハミング距離がｎである様に配置してある。DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, reference numeral 1 is a circular code plate having slits 2 which are physical codes indicating 0 or 1 arranged in the circumferential direction. As shown in FIG. 2, the slit 2 includes a thin one and a thick one. The thin slit 2a represents 0 and the thick slit 2b represents 1. These slits 2
a and 2b are arranged at equal pitch P on the same circular track T in the circumferential direction. The slit 2 has a Hamming distance of 1 or more between a codeword formed by taking n slits continuously from each position on the track and a codeword made by taking n slits continuously from other positions. And a code word formed by taking n continuous slits and the code word are 180 °
It is arranged so that the Hamming distance to a codeword composed of n slits located at opposite positions is n.
【００１２】ところで、スリット２を連続して複数配置
した場合、各スリットは０又は１を示すため、概念上、
スリットの集合を０又は１を要素とする数列として取り
扱うことができる。この様な観点に立てば、前記数列
中、数列中の各要素から連続してｎ個のスリットをとっ
て成る符号語と他の位置から連続してｎ個のスリットを
とって成る符号語とのハミング距離が１以上であるもの
は巡回数列と把握することができ、それは適当な初項と
生成多項式とから作れることが知られている。By the way, when a plurality of slits 2 are continuously arranged, each slit indicates 0 or 1, and therefore, conceptually,
A set of slits can be treated as a sequence of 0 or 1 elements. From such a point of view, in the above-mentioned number sequence, a codeword formed by taking n slits continuously from each element in the number sequence and a codeword obtained by taking n slits continuously from other positions A Hamming distance of 1 or more can be understood as a cyclic sequence, and it is known that it can be created from an appropriate first term and a generator polynomial.
【００１３】そのうちでも特に、巡回数列中の巡回する
部分を円形に配置した場合に、数列中の互いに１８０°
対向する位置にある２つの要素が互いに異なるものであ
る様な巡回数列はセルフコンプリメンタルコード（以下
「ＳＣＣ」と言う。）と呼ばれている。セルフコンプリ
メンタルコードから連続したｎ個の要素をとって成る符
号語と、該符号語とは１８０°対向する位置にあるｎ個
の要素から成る符号語とのハミング距離は符号語長ｎで
あることとなる。Among them, in particular, when the circulating portions in the sequence of numbers are arranged in a circle, they are 180 ° from each other in the sequence.
A cyclic sequence in which two elements located at opposite positions are different from each other is called a self-complementary code (hereinafter referred to as "SCC"). The Hamming distance between a codeword formed by taking n consecutive elements from the self-complementary code and a codeword made up of n elements located 180 ° opposite to the codeword is the codeword length n. It will be.
【００１４】巡回数列は、生成多項式に適当な符号語を
代入して得られる値を順次符号語に加えていくことで得
られることは広く知られているが、ＳＣＣを発生させる
方法を以下に説明する。一般に、生成多項式Ｇ（ｘ）に
適当な多項式を「２を法とした乗算」を施して得られる
多項式ｇ（ｘ）も又、生成多項式である。従って、ｇ
（ｘ）と適当な初項とから巡回数列を得ることができ
る。このうち、ＳＣＣを発生させることのできる生成多
項式ｇ（ｘ）を得るためには、適当な生成多項式Ｇ
（ｘ）と多項式ｘ2＋１とを乗算して得られる。長い巡
回性を得るためには、Ｇ（ｘ）にＭ系列の多項式を用い
るのが望ましく、例えば、 Ｇ（ｘ）＝ｘ4＋ｘ＋１ を用いれば、 ｇ（ｘ）＝（ｘ2＋１）×Ｇ（ｘ）＝（ｘ2＋１）×（ｘ
4＋ｘ＋１）＝ｘ6＋ｘ4＋ｘ3＋ｘ2＋ｘ＋１ と、ＳＣＣを発生させることができる生成多項式ｇ
（ｘ）を得ることができる。なお、「×」は２を法とし
た乗算であり、「＋」は排他的論理和を表している。こ
の生成多項式ｇ（ｘ）と初期値０００００１とから、次
の様なＳＣＣが得られる。 ０００００１１０００１００１０１１１１１００１１１
０１１０１… （「…」以下は繰り返しパターンである。）上記数列の
繰り返し部分である「…」以下を省略し、最後の項の
「１」と最初の項の「０」とが隣あう様に円形に配置す
ればＳＣＣを得ることができる。It is widely known that a cyclic sequence can be obtained by sequentially adding values obtained by substituting an appropriate codeword to a generator polynomial to a codeword. A method for generating SCC will be described below. explain. Generally, a polynomial g (x) obtained by subjecting the generator polynomial G (x) to "multiplication modulo 2" with an appropriate polynomial is also a generator polynomial. Therefore, g
A cyclic sequence can be obtained from (x) and an appropriate first term. Of these, in order to obtain a generator polynomial g (x) capable of generating SCC, an appropriate generator polynomial G
It is obtained by multiplying (x) by the polynomial x 2 +1. In order to obtain long cyclicity, it is desirable to use an M-sequence polynomial for G (x). For example, if G (x) = x 4 + x + 1 is used, g (x) = (x 2 +1) × G (X) = (x 2 +1) × (x
4 + x + 1) = x 6 + x 4 + x 3 + x 2 + x + 1 and a generator polynomial g capable of generating SCC
(X) can be obtained. In addition, "x" represents multiplication modulo 2, and "+" represents exclusive OR. From the generator polynomial g (x) and the initial value 000001, the following SCC is obtained. 0000011100100101111100111
01101 ... (“...” and the following are repeating patterns.) The following “...”, which is the repeating part of the above sequence, is omitted and “1” of the last term and “0” of the first term are adjacent to each other. SCC can be obtained by arranging in a circular shape.
【００１５】その様な配置で構成される数列中の連続し
た７つの要素からなる符号語は、順番に記すと次の様に
なる。A codeword composed of seven consecutive elements in a sequence formed by such an arrangement is as follows when written in order.
【００１６】 （０〜１８０°） （１８０°〜３６０°） ０００００１１ １１１１１００ ００００１１０ １１１１００１ ０００１１００ １１１００１１ ００１１０００ １１００１１１ ０１１０００１ １００１１１０ １１０００１０ ００１１１０１ １０００１００ ０１１１０１１ ０００１００１ １１１０１１０ ００１００１０ １１０１１０１ ０１００１０１ １０１１０１０ １００１０１１ ０１１０１００ ００１０１１１ １１０１０００ ０１０１１１１ １０１００００ １０１１１１１ ０１０００００ ０１１１１１０ １０００００１ 上記符号語同士のハミング距離は最低でも２であり１ビ
ットの読み取りミスがあった場合は、その様な符号語
は、該ＳＣＣ中には存在しないこととなる。又、１８０
°対向する位置にある２つの符号語同士は、対応する各
要素は互いに異なるものであり、そのハミング距離は符
号語長ｎ即ち７となる。(0-180 °) (180 ° -360 °) The Hamming distance of is at least 2, and if there is a 1-bit read error, such a code word does not exist in the SCC. Also, 180
The corresponding elements of the two code words located at the opposite positions are different from each other, and the Hamming distance is the code word length n, that is, 7.
【００１７】円形符号板１に上記ＳＣＣの各要素に対応
するスリットを配置し、該円形符号板１に対し相対回転
する極座標の所定の角度区域にある連続したｎ個のスリ
ットから成る符号語Ａを読み取る第１検出手段３を設け
て、該検出手段３から第１検出符号ａを算出手段６と判
別手段４とに出力する。前記極座標は、円形符号板１が
固定の場合には測定すべき回転体に対し静止した座標と
し、円形符号板１が回転体と一体に回転する場合は空間
座標系に対し静止した座標とする。Slits corresponding to the respective elements of the SCC are arranged on the circular code plate 1, and a code word A consisting of a series of n slits in a predetermined angular area of polar coordinates rotating relative to the circular code plate 1. Is provided and the first detection code a is output from the detection means 3 to the calculation means 6 and the determination means 4. The polar coordinates are coordinates that are stationary with respect to the rotating body to be measured when the circular code plate 1 is fixed, and coordinates that are stationary with respect to the spatial coordinate system when the circular code plate 1 rotates integrally with the rotating body. .
【００１８】又、第１検出手段３が読み取る符号語Ａと
は１８０°対向した位置にある連続したｎ個のスリット
から成る符号語Ｂを読み取る第２検出手段５を設け、該
検出手段５から第２検出符号ｂを算出手段６と判別手段
４とに出力する。第１検出手段３と第２検出手段５は、
レンズ、プリズム、リニアイメージセンサの組合せによ
り構成できるが、リニアイメージセンサについては、第
１検出手段と第２検出手段とで別々に２つ設けても、１
つのリニアイメージセンサを共有しても良い。又、算出
手段６はＣＰＵの様な演算装置及びＤＲＡＭ等の記憶装
置とから構成される。Further, a second detecting means 5 for reading a code word B consisting of continuous n slits at a position opposed to the code word A read by the first detecting means 3 by 180 ° is provided, and the second detecting means 5 is provided. The second detection code b is output to the calculation means 6 and the discrimination means 4. The first detecting means 3 and the second detecting means 5 are
The linear image sensor can be configured by combining a lens, a prism, and a linear image sensor, but even if two linear image sensors are separately provided for the first detecting unit and the second detecting unit,
You may share one linear image sensor. The calculating means 6 is composed of a computing device such as a CPU and a storage device such as a DRAM.
【００１９】判別手段４は、第１検出符号ａと第２検出
符号ｂとを照合して読み取りミスの有無を判別してその
結果を算出手段６に出力する。算出手段６は、該判別結
果と第１検出符号ａと第２検出符号ｂと記憶手段７に予
め記憶された対応表から第１検出手段３の絶対角度位置
を図３に示す手順で算出する。The discriminating means 4 collates the first detection code a and the second detection code b to discriminate the presence or absence of a reading error, and outputs the result to the calculation means 6. The calculation means 6 calculates the absolute angular position of the first detection means 3 from the discrimination result, the first detection code a, the second detection code b, and the correspondence table stored in advance in the storage means 7 in the procedure shown in FIG. .
【００２０】図３を参照し、処理はＳ１から開始され
る。Ｓ２で、第１検出手段３が、連続したｎ個のスリッ
トから成る符号語Ａを読み取って算出手段６に第１検出
符号ａを出力する。Ｓ３で、第２検出手段５は、符号語
Ａとは１８０°対向する位置にある符号語Ｂを読み込ん
で、算出手段６に第２検出符号ｂを出力する。Referring to FIG. 3, the process starts at S1. In S2, the first detecting means 3 reads the code word A consisting of continuous n slits and outputs the first detecting code a to the calculating means 6. In S3, the second detection means 5 reads the code word B located at a position opposite to the code word A by 180 ° and outputs the second detection code b to the calculation means 6.
【００２１】Ｓ４では判別手段４が第１検出符号ａと第
２検出符号ｂとのハミング距離ｄH（ａ，ｂ）を求めて
符号語長ｎと等しいか否かを判別する。読み取りミスの
ため、Ａ≠ａ又はＢ≠ｂのいずれかである場合はｄH
（ａ，ｂ）が符号語長ｎと等しくないため処理をＳ５に
移行させる。ｄH（ａ，ｂ）＝ｎであった場合は、読み
取りミスはなかったと判断して、処理をＳ６に移行させ
る。In S4, the discriminating means 4 obtains the Hamming distance dH (a, b) between the first detection code a and the second detection code b and discriminates whether or not it is equal to the code word length n. If either A ≠ a or B ≠ b due to a read error, dH
Since (a, b) is not equal to the codeword length n, the process proceeds to S5. If dH (a, b) = n, it is determined that there is no reading error, and the process proceeds to S6.
【００２２】Ｓ６で、算出手段６が記憶手段７に記憶さ
れた対応表中の符号語と第１検出符号ａとを照合する。
対応表中に、第１検出符号ａとハミング距離が０又はｎ
である符号語Ｃがあった場合、ハミング距離が０のとき
はＳ７に移行して第１検出手段３の絶対角度位置αをＣ
に対応する絶対角度θの値とし、ｎの場合はＳ８に移行
して絶対角度位置αをθに１８０°加えた値とする。In S6, the calculation means 6 collates the code word in the correspondence table stored in the storage means 7 with the first detection code a.
In the correspondence table, the first detection code a and the Hamming distance are 0 or n.
If the Hamming distance is 0, the absolute angular position α of the first detecting means 3 is set to C.
The value of the absolute angle .theta.
【００２３】０又はｎである符号語が存在しなかった場
合は、第１検出符号ａと第２検出符号ｂとの両方に検出
ミスがありながらｄH（ａ、ｂ）＝ｎが保たれたレアケ
ースである。通常「１」を示す太いスリット２ｂにゴミ
が付着して「０」を示す細いスリット２ａと読み誤るこ
とはあるが、細いスリットを太いスリットと読み誤るこ
とは希である。しかも、ＡとＢの対応する要素でその様
な読み誤りが同時に起こることは非常に確率が低い。こ
の場合には、Ｓ９で警報を出力して作業を終了する。When there is no code word which is 0 or n, dH (a, b) = n is maintained although there is a detection error in both the first detection code a and the second detection code b. It is a rare case. Usually, dust may adhere to the thick slit 2b indicating "1" and may be misread as the thin slit 2a indicating "0", but it is rare that the thin slit is misread as a thick slit. Moreover, it is extremely unlikely that such reading errors will occur simultaneously in the corresponding elements of A and B. In this case, an alarm is output in S9 and the work is finished.
【００２４】Ｓ４で、第１検出符号ａ又は第２検出符号
ｂに読み誤りがあると判断された場合には、Ｓ５に処理
が移る。Ｓ５ではＳ６と同様に、ハミング距離が０であ
る時はＳ１１に、ｎであった時はＳ１２に処理が移行
し、Ｓ１１ではＳ７と、Ｓ１２ではＳ８と同様の処理が
される。対応表に第１検出符号ａとハミング距離が０又
はｎなる符号語が存在しなかった場合には、第１検出符
号ａに読み取りミスがあるので、Ｓ１０に処理を移し、
第１検出符号ａに代わって第２検出符号ｂを用いる。If it is determined in S4 that the first detection code a or the second detection code b has a reading error, the process proceeds to S5. Similar to S6, in S5, the process shifts to S11 when the Hamming distance is 0, to S12 when the Hamming distance is n, and the same process as S7 in S11 and S8 in S12 is performed. If there is no code word having a Hamming distance of 0 or n with the first detection code a in the correspondence table, there is a reading error in the first detection code a, so the process proceeds to S10.
The second detection code b is used instead of the first detection code a.
【００２５】第２検出符号ｂとハミング距離が０である
符号語Ｃが対応表中に存在した場合は、Ｓ１０からＳ１
３に処理が移り、第１検出手段３の絶対角度位置αを符
号語Ｃに対応する絶対角度位置θに１８０°加えた値と
する。第２検出符号ｂとハミング距離がｎである符号語
Ｃが対応表中に存在した場合は、Ｓ１０からＳ１４へ処
理が移り、第１検出手段３の絶対角度位置αをθの値と
する。対応表中に０又はｎとなる符号語がいずれも存在
しなかった場合には、第２検出符号ｂにも読み取りミス
がある場合であり、第１検出手段３の絶対角度位置を求
めることができないためＳ１５に処理を移して警報を出
力して処理は終了する。When the second detection code b and the code word C having a Hamming distance of 0 are present in the correspondence table, S10 to S1.
3, the absolute angular position α of the first detection means 3 is set to a value obtained by adding 180 ° to the absolute angular position θ corresponding to the code word C. When the second detection code b and the code word C having the Hamming distance of n are present in the correspondence table, the process proceeds from S10 to S14, and the absolute angular position α of the first detection means 3 is set to the value of θ. If there is no code word of 0 or n in the correspondence table, it means that there is a reading error in the second detection code b, and the absolute angular position of the first detection means 3 can be obtained. Since this is not possible, the process moves to S15, an alarm is output, and the process ends.
【００２６】以上の処理により得られた絶対角度位置α
の値又は警報は、表示手段１０でされる。Absolute angular position α obtained by the above processing
Is displayed on the display means 10.
【００２７】なお、この様に、検出符号を対応表中の符
号語と照合して絶対角度位置を求める際、検出符号と対
応表中の符号語とのハミング距離が０であるものがあれ
ば、直ちにその符号語に対応する絶対角度位置が検出手
段の絶対角度位置に、ハミング距離が符号語長ｎである
ものがあればその符号語に対応する絶対角度位置に１８
０°加えた値が検出手段の絶対角度位置であるとするこ
とができる。従って、例えば前記巡回数列中の０〜１８
０°の範囲に対応する符号語のみを記憶しておく等、１
８０°対向する位置にあるいずれか一方の符号語のみを
円形符号板の絶対角度位置と対応させて記憶しておけば
よく、このため記憶手段７の記憶容量が半分で済む。As described above, when the detection code is collated with the code word in the correspondence table to obtain the absolute angular position, if the Hamming distance between the detection code and the code word in the correspondence table is 0, Immediately, the absolute angular position corresponding to the code word is at the absolute angular position of the detecting means, and if the Hamming distance is the code word length n, the absolute angular position is at the absolute angular position corresponding to the code word.
The value obtained by adding 0 ° can be regarded as the absolute angular position of the detecting means. Therefore, for example, 0 to 18 in the cycle sequence
Only the code words corresponding to the range of 0 ° are stored, for example, 1
Only one of the code words facing each other by 80 ° may be stored in association with the absolute angular position of the circular code plate, and therefore the storage capacity of the storage means 7 may be half.
【００２８】[0028]
【発明の効果】本発明によれば、読み取りミスの有無
を、検索作業を行うことなく簡易迅速に判別することが
できる。According to the present invention, the presence / absence of a reading error can be determined easily and quickly without performing a search operation.
【００２９】検出手段が検出した検出符号と対応表とを
照合して絶対角度位置を求める際、ハミング距離が０で
あるものばかりでなく、符号語長ｎであるものからも絶
対角度位置がわかるので、対応表中の符号語全てを照合
する必要がなく、検索時間が短くて済む。更には、１８
０°対向する位置にあるいずれか一方の符号語のみを円
形符号板の位置と対応させて対応表中に記憶しておけば
済むため、記憶手段は半分の容量があればよく、コスト
ダウンを図れる。When the detection code detected by the detection means and the correspondence table are collated to obtain the absolute angular position, not only the one having the Hamming distance of 0 but also the one having the code word length n can find the absolute angular position. Therefore, it is not necessary to collate all the code words in the correspondence table, and the search time can be shortened. Furthermore, 18
Since only one of the code words at the position facing each other by 0 ° is stored in the correspondence table in association with the position of the circular code plate, it is sufficient that the storage means has a half capacity, which leads to cost reduction. Can be achieved.
【図１】 本発明の一実施例のブロック図である。FIG. 1 is a block diagram of an embodiment of the present invention.
【図２】 円形トラック部分の拡大図である。FIG. 2 is an enlarged view of a circular track portion.
【図３】 本発明による処理手順の一例を示すフローチ
ャートである。FIG. 3 is a flowchart showing an example of a processing procedure according to the present invention.
１ 円形符号板 ２ スリット ３
第１検出手段 ４ 判別手段 ５ 第２検出手段 ６
算出手段 ７ 記憶手段1 circular code plate 2 slit 3
First detecting means 4 Discriminating means 5 Second detecting means 6
Calculation means 7 Storage means
Claims (2)
理的符号が同一円形トラックに等ピッチで、且つ、該ト
ラックの各位置から連続してｎ個の物理的符号をとって
成る符号語と他の位置から連続してｎ個をとって成る符
号語とのハミング距離が１以上となる様に配置されたも
のと、 前記円形符号板に対し相対回転する極座標の所定の角度
区域にある連続したｎ個の物理的符号から成る符号語を
読み取って第１検出符号を出力する第１検出手段と、 連続したｎ個の物理的符号から成る符号語と円形符号板
中の位置とを対応させた対応表を予め記憶しておく記憶
手段と、 前記第１検出符号と前記対応表とから第１検出手段の絶
対角度位置を算出する算出手段とを備えたアブソリュー
トエンコーダーにおいて、 前記円形符号板中の物理的符号は、連続したｎ個の物理
的符号をとって成る符号語と、該符号語とは１８０°対
向する位置にあるｎ個の物理的符号から成る符号語との
ハミング距離がｎである様に配置され、 第１検出手段が読み取る符号語とは１８０°対向した位
置にある符号語を読み取って第２検出符号を出力する第
２検出手段と、 第１検出符号と第２検出符号とを比較して検出ミスの有
無を判別する判別手段とを備えたことを特徴とするアブ
ソリュートエンコーダー。1. A circular code plate, wherein physical codes indicating 0 or 1 are formed on the same circular track at equal pitches, and n physical codes are continuously taken from each position of the track. A code word and a code word formed by continuously taking n pieces from other positions so that the Hamming distance is 1 or more, and a predetermined angular area of polar coordinates relative to the circular code plate. A first detecting means for reading a code word consisting of consecutive n physical codes in (1) and outputting a first detection code; and a code word consisting of consecutive n physical codes and a position in the circular code plate. In the absolute encoder, the absolute encoder includes a storage unit that stores in advance a correspondence table that associates with each other, and a calculation unit that calculates the absolute angular position of the first detection unit from the first detection code and the correspondence table. Physical code in code plate , Arranged so that the Hamming distance between a codeword formed by taking consecutive n physical codes and a codeword formed by n physical codes at a position facing each other by 180 ° is n The first detection code and the second detection code are compared with the second detection means which reads the code word at a position opposite to the code word read by the first detection means by 180 ° and outputs the second detection code. Absolute encoder, which is provided with a determining means for determining whether or not there is a detection error.
したｎ個の符号をとって成る符号語のうち１８０°対向
する位置にあるいずれか一方の符号語のみを円形符号板
の位置と対応させて予め記憶したものであることを特徴
とする請求項１記載のアブソリュートエンコーダー。2. The correspondence table stored in the storage means is such that only one of the code words, which are opposite to each other by 180 °, among the code words formed by taking consecutive n codes is the position of the circular code plate. The absolute encoder according to claim 1, wherein the absolute encoder is stored in association with each other.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33571393A JP3375708B2 (en) | 1993-12-28 | 1993-12-28 | Absolute encoder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33571393A JP3375708B2 (en) | 1993-12-28 | 1993-12-28 | Absolute encoder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07198420A true JPH07198420A (en) | 1995-08-01 |
| JP3375708B2 JP3375708B2 (en) | 2003-02-10 |
Family
ID=18291648
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP33571393A Expired - Fee Related JP3375708B2 (en) | 1993-12-28 | 1993-12-28 | Absolute encoder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3375708B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007163313A (en) * | 2005-12-14 | 2007-06-28 | Sokkia Co Ltd | Absolute encoder |
| JP2007259517A (en) * | 2006-03-20 | 2007-10-04 | Ricoh Co Ltd | Rotating body drive control device, image forming apparatus, and positional deviation correction method |
| JP2009268177A (en) * | 2008-04-22 | 2009-11-12 | Toshiba Corp | Non-contact master controller and fault detecting method for non-contact mater controller |
| JP2013029511A (en) * | 2011-07-28 | 2013-02-07 | Dr Johannes Heidenhain Gmbh | Method and apparatus for angle measurement |
-
1993
- 1993-12-28 JP JP33571393A patent/JP3375708B2/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007163313A (en) * | 2005-12-14 | 2007-06-28 | Sokkia Co Ltd | Absolute encoder |
| JP2007259517A (en) * | 2006-03-20 | 2007-10-04 | Ricoh Co Ltd | Rotating body drive control device, image forming apparatus, and positional deviation correction method |
| JP2009268177A (en) * | 2008-04-22 | 2009-11-12 | Toshiba Corp | Non-contact master controller and fault detecting method for non-contact mater controller |
| JP2013029511A (en) * | 2011-07-28 | 2013-02-07 | Dr Johannes Heidenhain Gmbh | Method and apparatus for angle measurement |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3375708B2 (en) | 2003-02-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR970003620B1 (en) | Axial Position Detector of Piston Rod | |
| US4414754A (en) | High resolution compass card position decoder | |
| US4701615A (en) | Measuring scale coding system for length or angle measuring instruments | |
| JP3176861B2 (en) | Position measuring device | |
| US4794251A (en) | Apparatus for measuring lengths or angles | |
| US10876863B2 (en) | Absolute position sensor using Hall array | |
| US5301005A (en) | Method and apparatus for determining the position of a retroreflective element | |
| US20040173735A1 (en) | Absolute incremental position encoder and method | |
| JPH0989595A (en) | Rotary encoder | |
| KR880013015A (en) | Rotation angle detection method and device | |
| JP3375708B2 (en) | Absolute encoder | |
| JP3442869B2 (en) | Optical absolute encoder | |
| JP4885670B2 (en) | Absolute type linear encoder | |
| JP2005500548A (en) | Method and apparatus for optical measurement data detection | |
| JPH05231879A (en) | Correcting method for detecting position | |
| US4901255A (en) | Method and apparatus for evaluating quadrature encoders | |
| CN111332504A (en) | Low-speed drive device for satellite and fast positioning method using the same | |
| JPS63187118A (en) | Position reading encoder | |
| US20220107208A1 (en) | Position-measuring device for measuring an absolute position | |
| JP4726220B2 (en) | Absolute encoder | |
| JPH06347287A (en) | Magnetic displacement/rotation detection sensor | |
| CN117968749B (en) | Angle encoder measurement result correction method and device | |
| JPH05252037A (en) | Rotary absolute encoder with error correction / detection function | |
| JPH04143620A (en) | Position detector | |
| JP2002228489A (en) | Disk for absolute encoder |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20071129 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20081129 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Year of fee payment: 7 Free format text: PAYMENT UNTIL: 20091129 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20091129 Year of fee payment: 7 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Year of fee payment: 8 Free format text: PAYMENT UNTIL: 20101129 |
|
| S533 | Written request for registration of change of name |
Free format text: JAPANESE INTERMEDIATE CODE: R313533 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Year of fee payment: 8 Free format text: PAYMENT UNTIL: 20101129 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Year of fee payment: 8 Free format text: PAYMENT UNTIL: 20101129 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20101129 Year of fee payment: 8 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20111129 Year of fee payment: 9 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Year of fee payment: 9 Free format text: PAYMENT UNTIL: 20111129 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20121129 Year of fee payment: 10 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Year of fee payment: 10 Free format text: PAYMENT UNTIL: 20121129 |
|
| S531 | Written request for registration of change of domicile |
Free format text: JAPANESE INTERMEDIATE CODE: R313531 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20121129 Year of fee payment: 10 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Year of fee payment: 10 Free format text: PAYMENT UNTIL: 20121129 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20131129 Year of fee payment: 11 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20131129 Year of fee payment: 11 |
|
| S531 | Written request for registration of change of domicile |
Free format text: JAPANESE INTERMEDIATE CODE: R313531 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Year of fee payment: 11 Free format text: PAYMENT UNTIL: 20131129 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| LAPS | Cancellation because of no payment of annual fees |