RU2434323C1 - Recursive code scale - Google Patents

Abstract

FIELD: information technology.

SUBSTANCE: recursive code scale has an information code track made in accordance with characters of a nonlinear binary sequence with length N=2ⁿ and n reader elements lying along the information code track with an angle pitch which is equal to the value of the quantum of the information code track δ=360°/N, a second information code track made in accordance with characters of N periods of a nonlinear binary sequence with length M=2^m, and m reader elements lying along the second information code track with an angle pitch (δ+δ₂), where δ₂=360°/NM is the value of the quantum of the second information code track and simultaneously the value of the quantum of the recursive code scale, outputs of pit reader elements in total determine the output length of the recursive code scale.

EFFECT: high versatility of the recursive code scale based on nonlinear binary sequences.

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Description

The invention relates to measuring equipment, in particular to analog-to-digital conversion, and in particular to the code scales of angular displacement converters to code.

At present, and in the future, one of the urgent and technically challenging tasks is the digital measurement of the angular displacements of the moving organs of numerous automatic control systems for various objects. This function is performed by angular displacement transducers.

The development of angular displacement transducers - suppliers of primary information is largely due to the widespread use of control microcomputers and various computing devices based on microprocessor and other large and very large integrated circuits.

In general, the angular displacement transducers, which are very diverse, are presented with a combination of the most diverse and, as a rule, high technical requirements.

Analysis of literature sources allows us to note the following advantages for transducers with direct conversion of displacement to code based on reading using spatial coding: the ability to use various physical methods of information reading, high speed, for encoders of angular displacement, high rotation speed of the encoded shaft (100 ... 150 r / min), high resolution (up to 20 dv. times.), resistance to external destabilizing factors, in zmozhnost meet various conditions of use, the possibility of movement in the functional conversion code and others. The main element of such transducers, the determining of the most important characteristics is the code scale (CABG).

The elementary section (quantum) of the code track (CD) of the scale is represented, as a rule, by one binary symbol, where the active sections of the scale correspond to single symbols, and passive sections correspond to zero.

Considering that the angular displacement transducers constructed by the reading method can be implemented on various physical methods of reading information, the active and passive elementary sections of the CD scale mean, respectively, the conductive and non-conductive parts of the scale with the contact method of reading information, transparent and opaque parts of the scale with photoelectric the method of information retrieval, the presence of a metal plate and insulation on the sections of the scale with the capacitive method of information retrieval, the presence and the absence of magnetic material on the parts of the scale with the electromagnetic method of reading information, etc.

The code scales of angular displacement transducers are known [1, 2], the mask of which is executed in an ordinary binary code or in a Gray code. In the classic version of constructing such scales, the number of code tracks is equal to the scale capacity. Therefore, the mass and dimensions of KS are mainly determined by the diameter of the scale and also increase with increasing bit depth. In this case, as a consequence, the manufacturability of such scales is deteriorating.

Closest to the technical solution and chosen by the authors for the prototype is a recursive code scale for angular displacement transducers, built on the basis of nonlinear binary sequences [3].

Recursive code scales based on nonlinear binary sequences have only one information code track with n readout elements along it with a step equal to one quantum of the scale and provide a resolution of δ = 360 ° / 2 ⁿ . Such scales can be implemented using most known methods of reading information.

The disadvantages of the prototype

The low adaptability of the recursive code scale is explained by the placement of reading elements along the code track in increments of one quantum. Since real reading elements have finite dimensions, when placed in increments of one quantum, they introduce restrictions on the dimensions of the recursive code scale for a given resolution.

In the present invention, the problem of improving the manufacturability of a recursive code scale based on non-linear binary sequences is solved.

To achieve a technical result, a recursive code scale containing an information code track, made in accordance with the symbols of a nonlinear binary sequence of length N = 2 ⁿ , and n readout elements located along the information code track with an angular step equal to the quantum value of the information code track δ = 360 ° / N, is equipped with a second information code track, made in accordance with the symbols of N periods of a nonlinear binary sequence of length M = 2 ^m , and m with reading elements, sizes along the second information code track with an angular step (δ + δ ₂ ), where δ ₂ = 360 ° / NM is the quantum value of the second information code track and at the same time the quantum value of the recursive code scale, the outputs of n and m reading elements in total determine the output bit depth recursive code scale.

New in the invention is:

- joint implementation of the mask recursive code scale in the form of two code tracks: information code track, made in accordance with the characters of a nonlinear binary sequence of length N = 2 ⁿ , the second information code track, made in accordance with the characters N periods of a nonlinear binary sequence of length M = 2 ^m , where the unit symbols of the sequences correspond to active sections of the scale, and to zero - passive;

- providing a resolution of the recursive code scale δ ₂ = 360 ° / NM, which is simultaneously the quantum value of the second information code track;

- supplying a recursive code scale m with reading elements placed along the second information code track with an angular step (δ + δ ₂ ).

The set of essential features in the present invention allowed:

- to increase the manufacturability of the recursive code scale due to the joint corresponding execution of the code mask of the scale in the form of two information code tracks based on non-linear binary sequences, as well as the corresponding placement of n and m reading elements on them.

As a result of this, we can conclude that the invention allows to obtain a technical result.

The invention is new, since the prior art on available sources of information did not reveal analogues with a similar set of features.

The invention is industrially applicable, as it can be used in all areas where high-precision positional determination of the angular position of an object is required using angular displacement transducers based on the claimed recursive code scales.

The invention is illustrated in the drawing, which shows a linear scan of a six-bit recursive code scale.

The inventive recursive code scale contains an information code track 1, a second information code track 2, reading elements 3, 4, 5 (n = 3) and reading elements 6, 7, 8 (m = 3).

To clarify the essence of the invention, we give some theoretical background.

In [4], KSs were proposed for angular displacement transducers, called pseudo-random code scales (PSKS) and constructed on the basis of using the theory of pseudorandom binary sequences of maximum length (M-sequences). PCSS have only one information code track, made in accordance with the symbols of the M-sequence a ₀ a ₁ ... a _L-1 , and n readout elements (SC) located along the track. Reading elements make it possible to obtain, with a full turn of the scale L = 2 ⁿ -1, various n-bit code combinations and provide the resolution of the angular displacement transducer based on the PSCH δ = 360 ° / L.

As follows from the method of constructing PCSS, its resolution is determined by the length of the M-sequence L = 2 ⁿ -1. Obviously, for any scale resolution, one (zero) code combination is lost. However, when constructing some technical systems using angular displacement transducers, it is necessary to provide a resolution of the latter that is a multiple of 2 ⁿ .

In [4], the recursive code scales (RCS) used in the invention, which are called nonlinear code scales (NCC) and are constructed on the basis of nonlinear binary sequences that provide the resolution of the scale δ = 360 ° / 2 ^{n, are considered} .

A non-linear sequence is a sequence of binary characters { a _j } of length N = 2 ⁿ that satisfy the recursive relation [5]

where the sign ⊕ - means a summation modulo two, and the indices for the characters of the sequence are taken modulo N. The initial values of the characters a ₀ a ₁ ... a _n-1 sequences are chosen arbitrarily.

In (1), h _i are coefficients depending on the form of a primitive polynomial of degree n with coefficients of the Galois field GF (2) [6], that is,

where h ₀ = h _n = 1, and h _i = 0,1 for 0 <i <n,

The first term in (1) determines the rule of formation linear with respect to the summation operator modulo 2 M-sequences. The second term (3) in (1) indicates the operation of multiplying the values of n-1 code symbols. This leads to the fact that the resulting sequence of characters becomes non-linear and a combination appears in it containing n consecutive zeros.

Table 1 shows the polynomials h (x) up to n = 20 inclusive, which can be used to generate the corresponding M-sequences [6].

Consider a method for constructing an n-bit single-rail RCS based on a nonlinear sequence.

1. Depending on the required bit depth of the scale n, a polynomial h (x) of degree n is selected from Table 1.

2. Using the recursive relation (1), the sequence { a _j } is generated.

3. The elementary sections (quanta) of the scale δ are performed in accordance with the symbols of the nonlinear sequence { a _j }, where symbols 1 of the sequence correspond to active and symbols to 0, passive sections of the information track. For definiteness, the sequence symbols are displayed on the information code track clockwise in the order a ₀ a ₁ ... a _N-1 .

4. Placing n reading elements on a scale with a step equal to one quantum, i.e. in accordance with the placement polynomial

The uniqueness of this arrangement is explained by the nonlinear properties of the sequence in question.

Let us explain the construction of the information code tracks of the RCS shown in the drawing.

, j=0,1,…, 4. Нелинейная последовательность должна быть нанесена на шкалу в виде активных (единицы последовательности) и пассивных (нули последовательности) участков (квантов) информационной кодовой дорожки 1, например, по ходу часовой стрелки, причем на информационную кодовую дорожку 1 шкалы наносится только один период последовательности. Нелинейная последовательность с периодом N=2ⁿ определяет число квантов информационной кодовой дорожки 1 шкалы, которое в данном примере равно N=8. Отсюда величина кванта δ=360°/N=360°/δ=45°. В примере размещение СЭ 3, 4 и 5 (n=3) вдоль информационной кодовой дорожки 1 определяется полиномом r(x)=1+х+x² и осуществляется с шагом, равным величине одного кванта информационной кодовой дорожки δ по ходу часовой стрелки.In the example, the information code track 1 of the scale is constructed in accordance with the symbols of the nonlinear sequence { a _j } = a ₀ a ₁ ... a ₇ = 0001011l of length N = 2 ⁿ = 2 ³ = 8, to obtain which the primitive polynomial h (x) = x ³ + x + 1, and the characters a _{3 + j of the} sequence { a _j } at the initial values a ₀ = a ₁ = a ₂ = 0 satisfy the recursive relation

, j = 0,1, ..., 4. The non-linear sequence must be plotted on the scale in the form of active (sequence units) and passive (sequence zeros) sections (quanta) of the information code track 1, for example, clockwise, and on the information code track 1 of the scale is applied only one period of the sequence. A non-linear sequence with a period of N = 2 ⁿ determines the number of quanta of the information code track 1 of the scale, which in this example is N = 8. Hence, the quantum value is δ = 360 ° / N = 360 ° / δ = 45 °. In the example, the placement of solar cells 3, 4, and 5 (n = 3) along the information code track 1 is determined by the polynomial r (x) = 1 + x + x ² and is carried out with a step equal to the value of one quantum of the information code track δ clockwise.

By fixing reading elements 3, 4 and 5 in sequence, the code combination when moving the RCS cyclically to one elementary section (quantum), for example, counterclockwise, we get eight different three-digit code combinations: 000, 001, 010, 101, 011, 111, 110 and 100.

According to this principle, theoretically a railroad recursive code scale of any capacity can be constructed.

However, this approach to the construction of one-way recursive code scales unambiguously involves placing reading elements along the information track of the scale with a step of one quantum. Since real sensing elements have finite dimensions, with this arrangement they will not allow the RCS (and, accordingly, the angular displacement transducer based on it) to be performed in the specified weight and size characteristics at high (10 and higher) scale digits, which reduces the manufacturability of its manufacture.

In order to improve the manufacturability of the recursive code scale in this invention, it is proposed to provide the recursive code scale with a second information code track, made in accordance with the symbols of N periods of a nonlinear binary sequence of length M = 2 ^m , and m reading elements placed along the second information code track with an angular step (δ + δ ₂ ), where δ2 = 360 ° / NM is the quantum value of the second information code track.

Improving the manufacturability of the recursive code scale is achieved due to the fact that:

- for the construction of the information and the second information code tracks of the RCS, nonlinear binary sequences of small length are used. In this case, the total bit depth of the two-track recursive code scale will be determined as (n + m);

- the use of a non-linear binary sequence of small length for constructing the information code track of the scale provides (due to a sufficient angular pitch δ) technological placement along such track n of SC;

- the placement of m reading elements along the second information code track is performed with an angular step (δ + δ ₂ ), where δ ₂ = 360 ° / NM is the quantum value of the second information code track.

, j=0,1,…,4. Нелинейная последовательность должна быть нанесена на РКШ в виде активных (единицы последовательности) и пассивных (нули последовательности) участков (квантов) информационной кодовой дорожки 2, например, по ходу часовой стрелки, причем на информационную кодовую дорожку 2 РКШ наносятся N=8 периодов последовательности. Восемь периодов нелинейной последовательности длиной M=2³=8 определяют число квантов второй информационной кодовой дорожки РКШ, которое в данном примере равно NM=64. Отсюда величина кванта второй информационной кодовой дорожки δ₂=360°/NM=360°/64=5,625°.In the drawing, the second information code track 2 of the CABG is constructed in accordance with the symbols of the nonlinear sequence { a _j } = a ₀ a ₁ ... a ₇ = 00010111 of length M = 2 ^m = 2 ³ = 8, to obtain which the primitive polynomial h (x) was used = x ³ + x + 1, and the characters a _{3 + j of the} sequence { a _j } for initial values a ₀ = a ₁ = a ₂ = 0 satisfy the recursive relation

, j = 0,1, ..., 4. A non-linear sequence should be plotted on the CSC in the form of active (sequence units) and passive (sequence zeros) sections (quanta) of the information code track 2, for example, clockwise, with N = 8 sequence periods being applied to the information code track 2 of the CSC. Eight periods of a nonlinear sequence of length M = 2 ³ = 8 determine the number of quanta of the second information code track of the RCS, which in this example is NM = 64. Hence, the quantum value of the second information code track is δ ₂ = 360 ° / NM = 360 ° / 64 = 5.625 °.

Thus, in the example, the placement of solar cells 6, 7, and 8 (m = 3) along the second information code track 2 is carried out with a step equal to the value (δ + δ ₂ ) = 45 ° + 5.625 ° = 50.625 ° clockwise.

In our example, the total bit depth provided by the information and the second information code tracks during the placement of the FE considered above will be (n + m) = 3 + 3 = 6.

Fixing the reading elements 3, 4, 5 and 6, 7, 8 sequentially a code combination, when moving the RCS cyclically to one elementary section (quantum) of the second information code track δ ₂ , for example, counterclockwise, we get 64 different six-digit code combinations, which correspond to 64 angular positions of the scale. These code combinations are given in table 2.

In this example, the same nonlinear binary sequence is used to build informational 1 and second informational code tracks 2 N = M = 8. In the general case, N ≠ M is allowed. For example, a six-bit recursive code scale can be constructed in two other ways, where (n = 4, m = 2) and (n = 2, m = 4). With an increase in the bit depth of a two-track recursive code scale, the number of variants of its construction also increases. This approach provides additional opportunities for choosing the most technologically advanced option for constructing an RCS (and, as a result, an angular displacement transducer based on it), which is associated with the possibility of multivariate placement of reading elements on the scale.

Thus, the present invention improves the manufacturability of recursive code scales built on the basis of nonlinear binary sequences.

Literature

1. Photoelectric information converters. / L.N. Presnukhin, S.A. Mayorov, I.V. Meskin, V.F. Shangin. Ed. L.N. Presnukhina. - M.: Mechanical Engineering, 1974. - 375 p.

2. Domrachev V.G., Meiko B.S. Digital angle converters: principles of construction, accuracy theory, control methods. - M .: Energoatomizdat, 1984. - 328 p.

3. Azov A.K., Ozhiganov A.A., Tarasyuk M.V. Recursive code scales. // Publishing house "Engineering" Information technology, 1998, No. 6. P.39-43.

4. Ozhiganov A.A. Pseudo-random code scales. // Izv. Universities. Instrument Engineering, 1987.V.30. No. 2. S. 40-43.

5. Agulnik A.R., Musaelyan S.S. Construction of nonlinear binary sequences. // Radio electronics. 1983. No. 4. P.19-28.

6. McWilliams F.D., Sloan N.D. Pseudorandom sequences and tables. // TIIER. 1976.V.64. No. 12. S.80-95.

Claims (1)

A recursive code scale containing an information code track, made in accordance with the symbols of a nonlinear binary sequence of length N = 2 ⁿ and n read elements, placed along the information code track with an angular step equal to the quantum value of the information code track δ = 360 ° / N, different the fact that the recursive code scale is equipped with a second information code track, made in accordance with the symbols of N periods of a nonlinear binary sequence of length M = 2 ^m , and m reading elements and, placed along the second information code track with an angular step (δ + δ ₂ ), where δ ₂ = 360 ° / NM is the quantum value of the second information code track and at the same time the quantum value of the recursive code scale, the outputs of n and m reading elements in total determine output bit depth of the recursive code scale.