JPH03170011A - Error detecting method by position detector and position detector with automatic error correcting function - Google Patents

Abstract

PURPOSE:To calculate position information according to a two-phase AC signal containing no error and to decrease man-hours and to attain highly accurate position detection by automatically detecting and correcting respective errors in a two-phase AC signal detected for the position detection. CONSTITUTION:The two-phase AC signal outputted by a two-phase AC signal detector 20 has an elliptic locus on its two-phase AC plane owing to respective errors. An offset error detector 11 performs arithmetic based upon an obtained coefficient value to detect offset errors Va and Vb, an amplitude error detector 12 detects an amplitude error Vbeta/Valpha, and a phase error detector 13 detects a phase error DELTAP=sinalpha. Then an offset error corrector 14 subtracts the errors Va and Vb from the instantaneous value of the two-phase AC signal and outputs signals Sa2 and Sb2. An amplitude error corrector 15 multiplies the signal Sa2 by the error Vbeta/Valpha and outputs signals Sa3 and Sb3 after the amplitude of a sin phase is corrected. A phase error corrector 16 has a small error DELTAP=sinalpha while cosalpha can be regarded nearly as 1 and outputs signals Sa4 and Sb4. A position detector 8 performs reverse trigonometric function conversion according to the signals Sa4 and Sb4 to detect the position theta in a gear tool.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to an error detection method in a position detection device that detects various errors included in a detection signal when detecting the position of a moving object; The present invention relates to a position detection device with an automatic error correction function that detects a position by automatically correcting a detected error.

(Prior Art) FIG. 8 is a configuration diagram of a conventional magnetic rotational position detection device. In the figure, gear 1. A two-phase AC signal detector 20 consisting of a permanent magnet 2 and a magnetic sensor 3.4 receives two-phase AC signals Vsinθ, which have a phase difference of 90° from each other.
Detect Vcosθ. Two samples each
Hold circuit 5 and A/D (analog/digital)
An instantaneous value detector 7 comprising a converter 6 samples the instantaneous values of the two-phase AC signals Vsinθ, Vcosθ from the two-phase AC signal detector 20 and converts them into digital data. The position signal detector 8 is triggered by the instantaneous value of the two-phase alternating current signal from the instantaneous value detector 7, and calculates θ-tan-'(Vsinθ/V
cos8) 17) Calculation: Detect the position θ within the gear teeth.

(Problem to be Solved by the Invention) However, in the conventional position detection device described above, two
Regarding the actual two-phase AC signal output from the phase AC signal detector, there may be an offset, different amplitudes, or a phase difference of 90°, so the signal may not match the Vsinθ that should be detected. , Vcosθ was detected as a different value. Therefore, since calculations were performed based on detected values that included this error,
There was a problem that highly accurate position detection was not possible.

In the past, such cases were sometimes dealt with by providing each of the above error correction circuits, but these conventional error extraction circuits required adjustment of variable resistors, etc. Due to adjustment errors, deterioration of characteristics due to aging of circuit elements, etc., it has not been possible to always perform highly accurate detection.

The present invention was made in view of the above-mentioned circumstances, and an object of the present invention is to provide an error detection method in a position detection device that can accurately detect a position, and a position detection device with an automatic error correction function. There is a particular thing.

(Means for Solving the Problems) The last invention relates to an error detection method in a position detection device that detects various errors included in a detection signal when detecting the position of a moving object. The above object of the invention is to provide a position detection device for detecting the position of a moving object based on two-phase AC signals having a periodic waveform corresponding to the moving distance of the moving object and having a predetermined phase difference from each other. , the mutual relationship of the two-phase AC signals is approximated and expressed by an elliptic equation, and the error with respect to the desired mutual relationship of the two-phase AC signals, which is expressed by a predetermined calculation formula combining the coefficients of the equation, is expressed as: The number of above 2 necessary to find the coefficient
This is achieved by determining it based on a set of instantaneous values of the phase alternating current signal. The invention also relates to a position detection device with an automatic error correction function that detects the position by automatically correcting the detected error.The above purpose is to detect the position of a moving object and to detect the position according to the distance traveled It has a periodic waveform,
and position signal detection means for generating two-phase AC signals having a predetermined phase difference from each other; amplitude error detection means for detecting mutual amplitude ratios of the two-phase AC signals, that is, amplitude errors; and said amplitude error detection means. amplitude error correction means for correcting the two-phase alternating current signal based on the value of the amplitude error detected by; and calculating the position of the moving body based on the two-phase alternating current signal subjected to the amplitude error correction. This is achieved by providing a position detecting means. Further, the present invention further includes an offset error detection means for detecting an offset error of the two-phase AC signal, and an offset error correction means for correcting the two-phase AC signal based on the value of the offset error detected by the offset error detection means. This is achieved by having a phase error detection means for detecting a phase error that is a deviation from the predetermined phase difference of the two-phase AC signal; This is achieved by comprising a phase error correction means for correcting the error.

(Function) In the present invention, the two-phase AC signal has an amplitude error. If the offset error k includes a phase error, the locus of the two-phase AC signal on the two-phase AC plane becomes an ellipse, so it can be calculated based on the relational expression between each coefficient of the ellipse equation and each of the above-mentioned errors. By detecting each of the errors using a required number of sets of instantaneous values of two-phase AC signals and correcting the two-phase AC signal based on the detected error values, two-phase AC signals that do not include the respective errors are detected. Since position information can be calculated based on the AC signal, position detection can be performed accurately.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 is a block diagram of a magnetic rotary position detecting device, which is an embodiment of the position detecting device of the invention.

Note that the two-phase AC signal detector 20, the instantaneous value detector 7, and the position signal detector 8 are the same as the conventional ones, so their explanations will be omitted.

First, the two-phase AC signal output from the two-phase AC signal detector 20 has an amplitude error. Assuming that offset and phase errors are included, the two-phase AC signal in that case is (1)
It can be expressed by the following equation, and its locus on the two-phase AC plane becomes an ellipse as shown in FIG.

Offset error detector 11. The amplitude error detector l2 and the phase error detector 13 apply the above ellipse equation to the general formula shown in equation (2), and calculate each coefficient of equation (2) using the instantaneous values of the five sets of two-phase AC signals. Calculate.

ax2+by2+cx+dy+exy+f-0
- - (2)? Here, the offset error detector 11 performs calculation -c based on the obtained coefficient value.
/2a, -d/2b and calculate the offset error va. v
b, the amplitude error detector 12 detects the amplitude error v, /V, by performing the calculation J1η, and the phase error detector 12 detects the amplitude error v, /V. 3 detects the phase error JP-sin α by performing the calculation -e/2F positive. Next, the offset error corrector l4 detects the offset error V■ detected by the offset error detector 11 from the instantaneous value of the -2 phase AC signal.
Vb is subtracted and removed, and the signal S. 2-Vm s in (θ
◆α》, Sb2-ν, cosθ are output. The amplitude error corrector l5 adds an amplitude ratio error V, /V, ·J to the signal Sa2.
Signal Sa3 multiplied by T81 and corrected for sin phase amplitude
・J'T7T・sa 2-V, sin(θ+a)
, Sb+-Sbz-V, cos θ is outputted. The phase error corrector 16 is configured such that the phase error AP-sin α is small<
, COSα can be considered to be almost 1, so by the addition theorem of trigonometric functions, sin(θ◆α)・sinθ・cos a
+sina-cosθ~sinθ+sina eco
Assuming that sθ is calculated using the phase error AP for the signal Sa3+Sb3, Saa=Sas-A P-Sb+ x
-Vp COS e Outputs signals Sa4, S, and 4. The position liV signal detector 8 detects the signals Sa4 . S
Inverse trigonometric transformation based on b4, i.e. θ・tan-'
(Saa/Sy) stan-' (VISsinθ/
'J/scosθ), and the position θ within the gear tooth is
Detect.

Hereinafter, the method for detecting each of the above-mentioned errors will be explained in detail.

Generally, the two-phase AC signal output from the two-phase AC signal detector 20 is the ideal two-phase AC signal No. 2 Vsin as described above.
θ, Vcosθ is not the amplitude error. Since it includes an offset error and a phase error, its output signal becomes as shown in equation (1). At this time, sinθ. On a two-phase AC plane with cos θ as the orthogonal coordinate axis, the trajectory of the signal based on equation (1) becomes an ellipse as shown in FIG. Therefore, if we assume that the general formula for this ellipse is as shown in equation (2), then (
2) The following relationship exists between each coefficient in the formula and each error.

Amplitude error v, /v, ・Ur direct t - Offset error V, -d/2b, Vb-c/2a Phase error
sin a・-e/(21TE'), in order to determine the general formula for the ellipse shown in equation (2), the points on the ellipse must be 5.
Just separate it into pieces. In other words, five sets of instantaneous values (
X+. y+), i-1 to 5. If you know, the simultaneous equations X1
"a+y1'b"X1C"311d+X1y+e"f-
0. By solving (i-1 to 5) and finding the coefficients, the ellipse can be uniquely determined, and based on the obtained coefficients, the calculations f correction, -c/2a, -d/2b, -e/( 2,/T
IT), the amplitude error, offset error, and phase error can be determined. In addition, if there is an error that does not require correction among the above-mentioned 3 ffl class errors, the error required for correction can be calculated by assuming an ellipse equation as in some specific examples explained below. can only be detected.

First, when only the amplitude error is included, the equation of the ellipse can be assumed to be ax''+by2+f-0, and the locus of the ellipse based on this equation is shown in Figure 3.In this case,
Two sets of instantaneous values (x+, y+) of a two-phase AC signal. in, 2
, the amplitude error V, /V (wov, /v. - JTr
It can be detected by a- - y+ -y2 XI -X2.

Further, when only the phase error is included, the equation of the ellipse can be assumed to be ax2◆a y 2◆exy+f·0, and the locus of the ellipse based on this equation is as shown in FIG.

In this case, ( is two sets of instantaneous values (x+, y
+). +−t4 to convert the phase error sin a to sin
α-e/2a = (X+"y+"-X,'-y2')/(2 (X
+V+-x2Y2)).

When an amplitude error and an offset error are included, the equation of the ellipse can be assumed to be ax2+by2+cx+dy+f-0, and the 1,900 traces of the ellipse based on this equation are shown in FIG. In this case, four sets of instantaneous values (X
+. y+). Using i1 to 4, the amplitude error M v,/
V-1 and offset error Va, V, as %/V, -r- 8+ + D+
, + [However, 81 (x+-x2) (X2-X3)
(X3-XI) (y:+-y4)11- (XI-X
2) (X3-X-1) (X++X2-1+-Xa)
(y2-y3). C- (X2-X3) (x+-
x4) (X4-X3) (y+-y2) . 0- (
y+-y2)(y2-y3)(ya-y1)(X3-X
4). E-(y+-y2)(ys-y4)(y+"y2
-y3-y4) (x2-x3). F-(y2-ys
) (!I'3-y4) (Y4-yz) (XI-X2
)] V. --d/2b- (^81+882◆A^3+^^4)/ +2 (A8, +88.+887◆8^l,)} [However, A^+-
(X3-X4) (X2-X4) (Xz-Xs)y
+'882- (XI-X:l1(X3-X4)(X4
-X+)yz', ^83-(XI-X2)(X2-
X4) (X+-X4)y3' * ^^4-(XI
-X2) (X2-X3) (X3-Xlly4'.
885” (X3-X+) (X2-X'4) (X2-X3
)yl. AAa-(Xl-X3) (X3-X4)
(X4-XI)3'21 AA7- (XI-X2)
(X2-X4) (X l -X4) y3. 886” (XI-X2) (X2-X3) (X3-XI)y
4. ]Vb"-C/2a■ - (BB r"882"[lB3+[l[l4)/
{2 (DBS”B1111”BI17+BB8)) [
However, BL-(y3-y4) (3'2-y4) (
y2-y3)X1'BB2-(y+-y3) (y3-
y4) (ya-y+)X2', lllh-b'+-
y2) (!/2-!/4) (y+-y4)X3".
BB. +- (y+-yz) (3'2-Y3) (y
3-yl)X4'. I]Bs” (y3-y4)(y
2-y4)(y2-y3)XI. +1 lo a-(y
l-ya) (y3-Ll) (y4-y+)X2. I
IBt"(3'+-y2) (y2-y4) (y+-L+
)X3, BBa(y+-3'2) (y2-y3)
(3's-yI) The result will be as shown in Figure 6. In this case, 3! of the two-phase AC signal! Instantaneous value of l1 (X+ .
y+) j”t ~3, the amplitude error V/I/v,
and phase error sin α is 1% /VJ − J””E7′T, and sin a−
e/(2-/'TF) [However, a・(yz'-y3'
)X+y+◆(3'3'-y+')XzY2◆(y+
'-y221 X+V3. b- (X2'-X3')
X+y+"(X3'-XI')X23'2"(X
+'-X2')X3y3.e-(X2'-X3')y+
"(Xs'-X+")Y2"(X+'-X2')yi'
] ? more detectable.

If offset errors and phase errors are included, the ellipse equation can be changed to ax'+ay2+cx+dy+exy+f-
It can be assumed that 0, and the elliptical sail trace based on this formula is as shown in FIG. In this case, using four sets of instantaneous values of the two-phase AC signal, the offset error V■vb and the phase error s
in α as V, --d/2a, V, --c/2a, sin a-
-Can be detected by e/2a.

Note that the present invention is not limited to the magnetic rotary position detecting device using gears as described above, but may also be applied to other position detecting devices, such as a magnetic rotary position detecting device using a mounted drum, or an optical type. The present invention can be applied to position detection devices that use two-phase alternating current signals, such as position detection devices and linear movement type position detection devices in addition to rotary type position detection devices.

(Effects of the Invention) As described above, according to the error detection method in the position detection device 43 and the position detection device with automatic error correction function 1; Amplitude difference. By automatically detecting and correcting offset errors and phase errors, position information can be calculated based on two-phase AC signals that do not include each error, which reduces the steps required for assembly and adjustment, and allows for constant high performance. Accurate position detection can be performed.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a magnetic rotary position detecting device which is an embodiment of the position detecting device of the present invention, and Figs. 2 to 7 show the 1,900 marks of two-phase AC No. The figure shown in FIG. 8 is a configuration diagram of a conventional magnetic rotational position detection device. DESCRIPTION OF SYMBOLS 1... Gear, 2... Permanent magnet, 3, 4... Magnetic sensor, 5... Sample and hold circuit, 6...
... A/D conversion circuit, 7... Instantaneous value detector, 8...
Position signal detection unit, 1l...Offset error detector, 1
2... Amplitude error detector, 13... Phase error detector,
l4... Offset error corrector, l5... Amplitude error corrector, 16... Phase error corrector.

Claims (1)

[Claims] 1. A position detection device that detects the position of a moving body based on a two-phase AC signal having a periodic waveform corresponding to the distance traveled by the moving body and having a predetermined phase difference from each other. The mutual relationship of the two-phase AC signals is approximated and expressed by an elliptic equation, and the error with respect to the desired mutual relationship of the two-phase AC signals expressed by a predetermined arithmetic expression combining the coefficients of the equation is, An error detection method in a position detection device, characterized in that the coefficient is determined based on a necessary number of sets of instantaneous values of the two-phase AC signal. 2. The above equation is a_1x^2+b_1y^2+f_1
Represented by = 0, there are calculations ▲ mathematical formulas, chemical formulas, tables, etc. ▼
2. The method for detecting an error in a position detecting device according to claim 1, wherein the amplitude ratio, that is, the amplitude error, determined by ▲ is a mathematical formula, a chemical formula, a table, etc., based on the two sets of instantaneous values. 3. The above equation is a_2x^2+a_2y^2+e_2
2. The position detection device according to claim 1, wherein a deviation from a predetermined phase difference, that is, a phase error, expressed by xy+f_2=0 and determined by calculation -e_2/2a_2, is determined based on the two sets of instantaneous values. Error detection method. 4. The above equation is a_3x^2+b_3y^2+e_3
Expressed as xy + f_3 = 0, calculation ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼
2. The method for detecting an error in a position detecting device according to claim 1, wherein the amplitude error and the phase error obtained by the calculation ▲There are mathematical formulas, chemical formulas, tables, etc.▼ are obtained based on the three sets of instantaneous values. . 5. The above equation is a_4x^2+b_4y^2+c_4
Represented by x + d_4y + f_4 = 0, the phase error and calculation determined by the operation ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ - c_4/2a_4, -d_4/2
The error detection method in a position detection device according to claim 1, wherein the offset error determined by b_4 is determined based on four sets of the instantaneous values. 6. The above equation is a_5x^2+a_5y^2+c_5
Claim 1: x+d_5y+e_5xy+f_5=0, and the offset error obtained by calculations -c_5/2a_5 and -d_5/2a_5 and the phase error obtained by calculation -e_5/2a_5 are obtained based on the four sets of instantaneous values. Error detection method in the position detection device described in . 7. The above equation a_6x^2+b_6y^2+c_6x
It is expressed as +d_6y+e_6xy+f_6=0, and there are calculations ▲mathematical formulas, chemical formulas, tables, etc.▼ or ▲mathematical formulas, chemical formulas,
There are tables, etc.Amplitude error calculated by ▼, calculation -c_6/2a_6, -d_6/2
Error detection in the position detecting device according to claim 1, wherein the offset error and the phase error determined by the calculation ▲There are mathematical formulas, chemical formulas, tables, etc.▼ are determined based on the five sets of instantaneous values. Method. 8. position signal generating means for generating two-phase alternating current signals having a periodic waveform according to the moving distance of the moving body and having a predetermined phase difference with each other, and a mutual amplitude ratio of the two-phase alternating current signals, i.e. amplitude error detection means for detecting an amplitude error;
amplitude error correction means for correcting the two-phase AC signal based on the value of the amplitude error detected by the amplitude error detection means; and the movement based on the two-phase AC signal subjected to the amplitude error correction. 1. A position detection device with an automatic error correction function, comprising a position detection means for calculating a body position. 9. A position signal generating means for generating a two-phase AC signal having a periodic waveform according to the moving distance of the moving body and having a predetermined phase difference from each other, and detecting an offset error of the two-phase AC signal. offset error detection means for correcting the two-phase alternating current signal based on the value of the offset error detected by the offset error detection means;
A position detection device with an automatic error correction function, comprising: a position calculation means for calculating the position of the moving object based on a phase alternating current signal. 10. Has a periodic waveform according to the moving distance of the moving object,
and position signal generation means for generating two-phase AC signals having a predetermined phase difference from each other; phase error detection means for detecting a phase error that is a deviation of the two-phase AC signal from the predetermined phase difference; phase error correction means for correcting the two-phase AC signal based on the value of the phase error detected by the phase error detection means; 1. A position detection device with an automatic error correction function, comprising: a position calculation means for calculating the position of.