JP3488875B2 - Encoder signal processing apparatus and method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an encoder signal processing apparatus and method, and more particularly to a novel improvement for improving the detection accuracy of absolute data.

[0002]

2. Description of the Related Art As a conventional device of this type, there can be mentioned, for example, the configuration of a signal processing circuit of an encoder shown in FIG. That is, in FIG. 3, reference numerals 1a and 1b indicate A output from a well-known encoder (not shown) including A phase and B phase.
They are a phase signal and a B-phase signal. Since the output values of the A-phase signal 1a and the B-phase signal 1b show almost accurate sine waveforms, the A-phase signal 1a is treated as COSθ and the B-phase signal 1b as SINθ here.

The A phase signal 1a and the B phase signal 1b are A
COS via the / D converter 2^-1Calculation unit 3 and SIN^-1Calculation
Input to the part 4, and as shown in FIG. 4 (b) and FIG. 4 (C)
COS^-1Data 3a and SIN^-1Detection accuracy for data 4a
Bad section 3a₁3a₂3a₃4a₁4a₂Contains
Therefore, as shown in FIG. 4, the A phase signal 1a and the B phase signal are
COS corresponding to a relatively linear section of the signal 1b
^-1Calculation unit 3 and SIN ^-1The output of the arithmetic unit 4 is sent to the selector 5.
And selectively combine them in the
I got the solution data.

[0004]

Since the conventional device is constructed as described above, the following problems exist. That is, when the A-phase signal and the B-phase signal are not complete sine wave signals, the output of the selector 5 becomes discontinuous as shown in FIG. 4D, and the detection accuracy deteriorates. .

That is, the A-phase output and the B-phase output of the encoder are not accurate sine wave signals with a 90 ° phase difference, but an error is included in the phase difference. Since it was converted into information (absolute data), the error of the phase difference greatly affected the accuracy of the position information.

The present invention has been made to solve the above problems, and in particular, the absolute information is detected by correcting the position information using the average value of the phase error in the above-mentioned four sections. An object of the present invention is to provide an encoder signal processing device and method with improved accuracy.

[0007]

An encoder signal processing apparatus according to the present invention converts an A-phase signal and a B-phase signal of an encoder into a CO signal.
When expressed as Sθ and SINθ, A = COSθ, B =
Based on the A-phase signal, CO
An intersection of the COS ^-1 calculation unit that calculates S ^-1 A, the SIN ^-1 calculation unit that calculates SIN ^-1 B based on the B-phase signal, the intersection of the A-phase signal and the B-phase signal, or these One cycle of the A-phase signal and the B-phase signal is divided at the points where the amplitudes of the signals are equal and the directions of vibrations are opposite to each other, and the average error of the errors contained in each divided section is obtained. An average error calculation unit, an A phase correction unit that corrects the A phase signal for each section based on the average error, and a B phase correction unit that corrects the B phase signal for each section based on the average error And a waveform synthesizing unit for synthesizing the A-phase signal corrected by the A-phase correcting unit and the B-phase signal corrected by the B-phase correcting unit,
The configuration is such that the output of the waveform synthesizing unit is used as absolute data, the intersections with the A-phase signal and the B-phase signal, and the amplitudes of these signals are equal, and the directions of vibrations are opposite to each other. At this point, one cycle of the A-phase signal and the B-phase signal is divided into four, and the average error of the errors included in each of the four divided sections is obtained. Further, the encoder signal processing method of the present invention, when the A-phase signal and the B-phase signal of the encoder are represented by COSθ and SINθ,
For A and B such that A = COSθ and B = SINθ, the above A
The step of calculating COS ^-1 A based on the phase signal, the step of calculating SIN ^-1 B based on the B phase signal, the intersection of the A phase signal and the B phase signal, or the amplitude of these signals Dividing one cycle of the A-phase signal and the B-phase signal at points where they are equal and have opposite vibration directions, and obtain an average error of errors included in each of the divided sections;
Correcting the A-phase signal for each section based on the average error, correcting the B-phase signal for each section based on the average error, the corrected A-phase signal and the correction And a step of synthesizing the generated B-phase signal, wherein the synthesized output is used as absolute data, and an intersection of the A-phase signal and the B-phase signal,
And one period of the A-phase signal and the B-phase signal is divided into four at the points where the amplitudes of these signals are equal and the directions of vibrations are opposite to each other, and each period is divided into four. This is a configuration for obtaining the average error of the errors.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of an encoder signal processing apparatus and method according to the present invention will be described in detail below with reference to the drawings. The same or equivalent parts as those of the conventional device are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 1, in the encoder signal processing device of the present invention, the A phase signal 1a and the B phase signal 1b are A
It is input to the COS ⁻¹ calculation unit 3 and the SIN ⁻¹ calculation unit 4 via the / D converter 2, and the Δθ ₁ calculation unit 10 that is the first error calculation unit and the Δθ ₂ calculation that is the second error calculation unit. Unit 11, Δθ ₃ calculation unit 12 which is the third error calculation unit, and
It is input to the Δθ ₄ calculation unit 13, which is the fourth error calculation unit.

Here, the Δθ ₁ calculation unit 10 to the Δθ ₄ calculation unit 1
The calculation of the error in 3 is performed as follows. First, the intersection of the A-phase signal 1a and the B-phase signal 1b, or
There are 5 points (A, B, C, D and E in FIG. 2) in which one signal has the same amplitude and opposite vibration directions in one cycle when both ends are included. The cycle is divided into _four sections θ _{1 to} θ 4 sandwiched between these 5 points, and phase errors Δθ _{1 to} Δθ ₄ are calculated for each section. In general, if the sine wave has a phase error Δθ, the phase error Δθ is
Since it can be expressed as = π / 2−SIN ⁻¹ K, Δθ ₁ to Δθ ₄ are obtained based on this equation (see FIG. 2).

The COS ^-1 data 3a and the SIN ^-1 data 4a output from the COS ^-1 calculation unit 3 and the SIN ^-1 calculation unit 4 are input to the A phase correction unit 14 and the B phase correction unit 15, respectively. It Δθ ₁ calculation unit 10, Δθ ₂ calculation unit 11,
The outputs of the Δθ ₃ calculation unit 12 and the Δθ ₄ calculation unit 13 are Δ
A Δθ _m calculator 16 that calculates an average error Δθ _m that is an average value (average of four errors) of θ ₁ , Δθ ₂ , Δθ ₃ and Δθ _4.
Entered in.

The average error Δθ _m output from the Δθ _m calculation unit 16 is input to the A-phase correction unit 14 and the B-phase correction unit 15, and the COS ⁻¹ data 3 is used by using the average error Δθ _m.
a and the SIN- ¹ data 4a are corrected for each section (? _{1 to} ? ₄ ). The corrected COS data and SIN data are input to the waveform synthesizer 17 and output as absolute data (position data) 17a.

As described above, since the encoder signal processing device of the present invention is configured as described above, when the A-phase signal and the B-phase signal are not perfect sine wave signals, or the distortion due to the offset or the harmonic component is caused. It is possible to provide an encoder signal processing device and method capable of outputting absolute data composed of continuous data with high detection accuracy even when the encoder signal is included.

[0014]

The encoder signal processing device of the present invention converts the A-phase signal and the B-phase signal of the encoder into COSθ and SIN.
When expressed as θ, for A and B such that A = COS θ and B = SIN θ, a COS ⁻¹ calculation unit that calculates COS ⁻¹ A based on the A phase signal, and a SIN ⁻¹ based on the B phase signal.
The SIN ^-1 calculation unit for calculating B and the intersection of the A-phase signal and the B-phase signal, or the amplitudes of these signals are equal,
And an average error calculator that divides one period of the A-phase signal and the B-phase signal at points where the directions of vibrations are opposite to each other and obtains an average error of errors included in each of the divided sections,
An A-phase correction unit that corrects the A-phase signal for each section based on the average error, a B-phase correction unit that corrects the B-phase signal for each section based on the average error, and the A-phase correction Phase signal corrected by the B-phase and B phase corrected by the B-phase correction unit
Since the waveform synthesizing unit for synthesizing the phase signal is provided and the output of the waveform synthesizing unit is used as the absolute data, it is possible to provide an encoder signal processing device having a simple configuration and high detection accuracy. Further, the intersection of the A-phase signal and the B-phase signal and the amplitudes of these signals are equal, and
Since one cycle of the A-phase signal and the B-phase signal is divided into four at the points where the directions of vibrations are opposite to each other, and the average error of the errors included in each of the four divided sections is obtained, the detection accuracy is further improved. It is possible to provide a high encoder signal processing device. Further, in the encoder signal processing method of the present invention, when the A-phase signal and the B-phase signal of the encoder are represented by COSθ and SINθ, A and B such that A = COSθ and B = SINθ
On the other hand, a step of calculating COS ^-1 A based on the A-phase signal, a step of calculating SIN ^-1 B based on the B-phase signal, an intersection of the A-phase signal and the B-phase signal, or Of the A-phase signal and the B-phase signal are divided at the points where the amplitudes of the signals are equal and the directions of the vibrations are opposite to each other, and the average error of the errors included in each divided section is calculated. A step of obtaining, a step of correcting the A phase signal for each section based on the average error, a step of correcting the B phase signal for each section based on the average error, and the corrected A phase Since a signal and the corrected B-phase signal are combined and the combined output is used as absolute data, it is possible to provide an encoder signal processing device with a simple configuration and high detection accuracy. In addition, one cycle of the A-phase signal and the B-phase signal is defined at the intersection with the A-phase signal and the B-phase signal, and at the points where the amplitudes of these signals are equal and the directions of vibrations are opposite to each other. Since it is divided into four and the average error of the errors included in each of the four divided sections is obtained, it is possible to provide an encoder signal processing method with higher detection accuracy.

[Brief description of drawings]

FIG. 1 is a configuration diagram schematically showing a circuit configuration of an encoder signal processing device according to the present invention.

FIG. 2 is a characteristic diagram showing various waveforms in the encoder signal processing device according to the present invention.

FIG. 3 is a configuration diagram schematically showing a circuit configuration of a conventional encoder signal processing device.

FIG. 4 is a characteristic diagram showing various waveforms in a conventional encoder signal processing device.

[Explanation of symbols]

1a A phase signal 1b B phase signal 2 A / D converter 3 COS ^-1 calculation unit 3a COS ^-1 data 4 SIN ^-1 calculation unit 4a SIN ^-1 data 10 Δθ ₁ calculation unit 11 Δθ ₂ calculation unit 12 Δθ ₃ calculation Section 13 Δθ ₄ calculating section 14 A-phase correcting section 15 B-phase correcting section 16 Δθ _m calculating section 17 waveform synthesizing section 17a absolute data

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01D 5/00-5/62 G01B ⁷ /00-7/34

Claims (4)

(57) [Claims] 1. An A-phase signal (1a) and a B-phase signal of an encoder
When (1b) is expressed as COSθ and SINθ, A = CO
For A and B such that Sθ and B = SINθ, the A phase signal (1
COS ^-1 calculation unit (3) that calculates COS ^-1 A based on a)
And S for calculating SIN ^-1 B based on the B-phase signal (1b)
The IN ^-1 operation unit (4), the A phase signal (1a) and the B phase signal (1
An average error calculator that calculates the average error of each error calculated at the intersection with b) or at the points where the amplitudes of these signals (1a, 1b) are equal and the directions of vibrations are opposite to each other. (16), an A-phase correction unit (14) for correcting the section in which the average error of the A-phase signal is obtained based on the average error, and the average error of the B-phase signal based on the average error. B phase correcting section (15) for correcting the obtained section, and the A phase correcting section
A waveform synthesizing section (17) for synthesizing the A-phase signal corrected in (14) and the B-phase signal corrected in the B-phase correcting section (15),
An encoder signal processing device, characterized in that the output (17a) of the waveform synthesizer (17) is used as absolute data. 2. One of the A-phase signal (1a) and the B-phase signal (1b)
Four points in the cycle where the A-phase signal (1a) and the B-phase signal (1b) intersect, and the amplitudes of these signals (1a, 1b) are equal and the directions of vibrations are opposite to each other. The encoder signal processing device according to claim 1, wherein an average error of the respective errors at the points is obtained. 3. A-phase signal (1a) and B-phase signal of an encoder
When (1b) is expressed as COSθ and SINθ, A = CO
For A and B such that Sθ and B = SINθ, the A phase signal (1
calculating COS ^-1 A based on a), and the B-phase signal
The step of calculating SIN ^-1 B based on (1b) and the intersection of the A phase signal (1a) and the B phase signal (1b), or the amplitudes of these signals (1a, 1b) are equal, and Obtaining an average error of each error at a plurality of points where the directions of vibrations are opposite to each other, correcting a section in which the average error of the A-phase signal is obtained based on the average error, and the average error And a step of synthesizing the corrected A-phase signal and the corrected B-phase signal. An encoder signal processing method characterized in that (17a) is used as absolute data. 4. One of the A-phase signal (1a) and the B-phase signal (1b)
Four points in the cycle where the A-phase signal (1a) and the B-phase signal (1b) intersect, and the amplitudes of these signals (1a, 1b) are equal and the directions of vibrations are opposite to each other. 4. The encoder signal processing method according to claim 3, wherein an average error of the respective errors at the points is calculated.