JP2018112450A - Rotational angle detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress erroneous determination that a sin signal and a cos signal are normal despite the fact that abnormality occurs in the sin signal and the cos signal from a resolver.SOLUTION: A resolver digital converter includes a first calculation part for calculating an angular speed of a rotation shaft. An abnormality determination device includes: a second calculation part for calculating a time derivative value of a sin signal and a time derivative value of a cos signal; a third calculation part for calculating a first multiplication value for multiplying the calculated angular speed by the cos signal and a second multiplication value for multiplying the calculated angular speed by a value -1 and the sing signal; and a determination part for determining that abnormality occurs in the sin signal when the sin signal and the first multiplication value of the time derivative value do not coincide with each other by comparing the time derivative value of the sin signal and the first multiplication value, and determining that the abnormality occurs in the cos signal when the time derivative value of the cos signal and the second multiplication value do not coincide with each other by comparing the time derivative value of the cos signal and the second multiplication value.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rotation angle detection device, and more particularly to a rotation angle detection device including a resolver and a resolver digital converter.

  Conventionally, as this type of rotation angle detection device, a device including a resolver and a resolver digital converter (R / D converter) has been proposed (see, for example, Patent Document 1). The resolver digital converter converts a sin signal (sin phase signal) and a cos signal (cos phase signal) from the resolver into a digital angle signal. In this apparatus, an abnormality in the sin signal and the cos signal is detected by using the fact that the sum of squares of the sin signal and the cos signal from the resolver becomes 1.

JP 2008-122216 A

  However, in the above-described rotation angle detection device, when an abnormality occurs in which the sin signal or the cos signal is fixed at an intermediate value between the value 0 and the value 1, the sum of squares of the sin signal and the cos signal is the value 1. It may become. In this case, although the sin signal and the cos signal are abnormal, it is erroneously determined to be normal.

  The main object of the rotation angle detection device of the present invention is to prevent erroneous determination as normal despite the occurrence of an abnormality in the sine signal and cos signal from the resolver.

  The rotation angle detection device of the present invention employs the following means in order to achieve the main object described above.

The rotation angle detection device of the present invention is
A resolver attached to the rotating shaft;
A resolver digital converter that converts a sin signal and a cos signal from the resolver into digital values, and calculates a rotation angle of the rotation shaft from the digital values;
An abnormality determination device for determining whether an abnormality has occurred in the sin signal or the cos signal;
A rotation angle detection device comprising:
The resolver digital converter is:
A first calculation unit for calculating an angular velocity of the rotating shaft;
Have
The abnormality determination device is
A second calculation unit for calculating a time differential value of the sin signal and a time differential value of the cos signal;
A third calculation unit for calculating a first multiplication value obtained by multiplying the calculated angular velocity by the cos signal and a second multiplication value obtained by multiplying the calculated angular velocity by a value −1 and the sin signal;
The time differential value of the sin signal is compared with the first multiplication value, and when the time differential value of the sin signal and the first multiplication value do not match, it is determined that an abnormality has occurred in the sin signal, Judgment by comparing the time differential value of the cos signal with the second multiplication value and determining that an abnormality has occurred in the cos signal when the time differential value of the cos signal does not match the second multiplication value And
Having
This is the gist.

  In the rotation angle detection device of the present invention, the first calculation unit of the resolver digital converter calculates the angular velocity from the sin signal and the cos signal from the resolver. The second calculation unit of the abnormality determination device calculates the time differential value of the sin signal and the time differential value of the cos signal, and the third calculation unit calculates and calculates the first multiplication value obtained by multiplying the calculated angular velocity by the cos signal. A second multiplication value obtained by multiplying the obtained angular velocity by the value -1 and the sin signal is calculated. The abnormality determining unit compares the differential value of the sin signal with the first multiplication value, and determines that an abnormality has occurred in the sin signal when the time differential value of the sin signal does not match the first multiplication value. When the sin signal is normal, the time differential value of the sin signal is equal to the first multiplication value. When an abnormality occurs in which the sin signal becomes a constant value (a value that does not change with time), the time differential value of the sin signal becomes 0, so that the time differential value of the sin signal is different from the first multiplication value. It may become. Therefore, by comparing the time differential value of the sin signal with the first multiplication value and determining that the sin signal has an abnormality when the time differential value of the sin signal does not match the first multiplication value, the sin signal It is possible to suppress erroneous determination that the sine signal is normal when an abnormality in which becomes a constant value occurs. When the cos signal is normal, the time differential value of the cos signal is equal to the second multiplication value. When an abnormality occurs in which the cos signal has a constant value (a value that does not change with time), the time differential value of the cos signal is 0, and the time differential value of the cos signal is different from the second multiplication value. . Therefore, the time differential value of the cos signal is compared with the second multiplication value, and when the time differential value of the cos signal and the second multiplication value do not match, it is determined that an abnormality has occurred in the cos signal, whereby the cos signal It is possible to suppress erroneous determination that the cos signal is normal when there is an abnormality in which becomes a constant value. As a result, it is possible to suppress erroneous determination as normal despite the occurrence of abnormality in the sin signal and cos signal from the resolver.

It is a block diagram which shows the outline of a structure of the rotation angle detection apparatus 20 as 1st Example of this invention. 4 is an explanatory diagram for explaining a state in which a resolver 22 is attached to a rotary shaft A connected to a rotor of a motor M. FIG. It is explanatory drawing which shows an example of the time change of the output signal of the output coils 126 and 127. FIG. It is a block diagram which shows the outline of a structure of the rotation angle detection apparatus 220 as 2nd Example of this invention. It is a block diagram which shows the outline of a structure of the rotation angle detection apparatus 320 of a modification.

  Next, the form for implementing this invention is demonstrated using an Example.

  FIG. 1 is a configuration diagram showing an outline of a configuration of a rotation angle detection device 20 as a first embodiment of the present invention. FIG. 2 is an explanatory diagram for explaining a state in which the resolver 22 is attached to the rotary shaft A connected to the rotor of the motor M. The rotation angle detection device 20 is configured, for example, as a device that detects the rotation angle of the rotation axis A, and includes a resolver 22 and a microcomputer 30.

  As shown in FIG. 2, the resolver 22 is attached to the rotating shaft A, and a rotor 124 as a magnetic body that rotates integrally with the rotating shaft A, and an alternating current having a constant frequency is applied as an excitation signal from an oscillation circuit (not shown). And a stator 128 as a magnetic body that incorporates output coils 126 and 127 that are electrically shifted by 90 degrees (so that the phase difference is 90 degrees). FIG. 3 is an explanatory diagram showing an example of the time change of the output signals of the output coils 126 and 127. The output signals of the output coils 126 and 127 are signals generated in accordance with the change in the gap between the rotor 124 and the stator 128 caused by the rotation of the elliptical rotor 124, and complement the peak value as shown in FIG. Sometimes the signals are sinusoidal and cosine wave signals (hereinafter, the sinusoidal signal is called “sin signal X” and the cosine wave signal is called “cos signal Y”). The voltage amplitudes x and y of the sin signal X and the cos signal Y can be calculated by the following equations (1) and (2) using the angular velocity ω of the resolver 22. Hereinafter, the “voltage amplitudes x and y of the sin signal X and the cos signal Y” may be simply referred to as “sin signal X and cos signal Y”. In formulas (1) and (2), “A” is an integer.

x = A ・ sin (ωt) ・ ・ ・ (1)
y = A ・ cos (ωt) ・ ・ ・ (2)

  The microcomputer 30 is mainly configured by a CPU (not shown), and includes an AD converter 32, a resolver digital converter (hereinafter referred to as “RD converter”) 34, and an arithmetic unit 36 in addition to the CPU. In addition, the microcomputer 30 includes a ROM, a RAM, an input / output port, a communication port, etc. (not shown).

  The AD converter 32 receives the sin signal X and the cos signal Y from the resolver 22, converts the input sin signal X and the cos signal Y into digital values, and outputs them.

  The RD converter 34 calculates the resolver angle φ from the sin signal X and the cos signal Y from the AD converter 32. The RD converter 34 calculates and outputs a resolver angle φ, an angular velocity ω, and an angular velocity (−ω) obtained by multiplying the angular velocity ω by a value of −1.

  The computing unit 36 is configured as a device that performs operations such as differentiation and multiplication, and comparison operations.

  In the rotation angle detection device 20 configured as described above, when the sin signal X and the cos signal Y from the resolver 22 are input to the microcomputer 30, the AD converter 32 of the microcomputer 30 converts the sin signal X and the cos signal Y into digital values. And output to the RD converter 34. The RD converter 34 to which the digital values of the sin signal X and the cos signal Y are input calculates and outputs the rotation angle (resolver angle, that is, the rotation angle of the rotation axis A) φ of the resolver 22 from the sin signal X and the cos signal Y. To do.

  Next, the operation of the rotation angle detection device 20 configured as described above, particularly the operation when determining whether or not an abnormality has occurred in the sin signal X and the cos signal Y from the resolver 22 will be described.

  When the sin signal X and the cos signal Y from the resolver 22 are input to the microcomputer 30, the microcomputer 30 converts the sin signal X and the cos signal Y into digital values by the AD converter 32 and converts the sin signal X and the cos signal Y into digital values. And output.

  The RD converter 34 to which the digital value is input calculates the angular velocity ω, (−ω) of the resolver 22 from each digital value, and outputs it to the calculator 36.

  The arithmetic unit 36 to which the digital values of the sin signal X and the cos signal Y and the angular velocity ω, (−ω) of the resolver 22 are input uses the digital values of the sin signal X and the cos signal Y to obtain the sin signal X and the cos signal Y. Time differential values dX / dt, dY / dt, a product ωY of the cos signal Y and the angular velocity ω, and a product −ωX of the sin signal X and the angular velocity (−ω).

  Then, the calculator 36 compares the time differential value dX / dt and the product ωY, and outputs a signal Rsin indicating the comparison result. When the time differential value dX / dt and the product ωY are equal, it is determined that the sin signal X is normal, a signal indicating that the sin signal X is normal is output as the signal Rsin, and the time differential value dX / dt If the product ωY is different from the product ωY, it is determined that an abnormality (for example, an abnormality that does not change with time (signal fixing abnormality), etc.) has occurred in the sin signal X, and an abnormality has occurred in the sin signal X as the signal Rsin. Output a signal indicating that Here, the reason why it is possible to determine whether or not an abnormality has occurred in the sin signal X by comparing the time differential value dX / dt and the product ωY will be described.

  When the sin signal X is normal, the time differential value dX / dt and the product ωY can be obtained by the following equations (3) and (4) using the equations (1) and (2) described above. Therefore, when the sin signal X is normal, the time differential value dX / dt and the product ωY are equal. When an abnormality occurs in the sin signal X, the time differential value dX / dt is a constant value of 0, and the time differential value dX / dt and the product ωY may be different values. Therefore, it is possible to determine whether or not an abnormality has occurred in the sin signal X by comparing the time differential value dX / dt and the product ωY. In this way, by comparing the time differential value dX / dt and the product ωY to determine whether or not an abnormality has occurred in the sin signal X, it is normal even though the abnormality has occurred in the sin signal X. It can suppress misjudging that there exists.

dX / dt = A ・ ω ・ cos (ω ・ t) ・ ・ ・ (3)
ωY = A ・ ω ・ cos (ω ・ t) ・ ・ ・ (4)

  The computing unit 36 compares the time differential value dY / dt and the product (−ωX), and determines that the cos signal Y is normal when the time differential value dY / dt and the product (−ωX) are equal. When a signal indicating that the cos signal Y is normal is output as the signal Rcos, and the time differential value dY / dt and the product (−ωX) are different, the cos signal Y is abnormal (for example, signal sticking abnormality or the like). It determines with having produced, and the signal which shows that abnormality has arisen in cos signal Y as signal Rcos is output. When the cos signal Y is normal, the time differential value dY / dt and the product (−ωX) can be obtained by the following equations (5) and (6) using the equations (1) and (2) described above. When the cos signal Y is normal, the time differential value dY / dt and the product (−ωX) are equal to each other, and when the cos signal Y has a signal sticking abnormality, the time differential value dY / dt becomes the value 0, and the time differential The value dY / dt and the product (−ωX) are different values. Therefore, it is possible to determine whether or not an abnormality has occurred in the cos signal Y by comparing the time differential value dY / dt and the product (−ωX). Thereby, it is possible to suppress erroneous determination that the cos signal Y is normal although there is an abnormality.

dY / dt = -A ・ ω ・ sin (ω ・ t) ・ ・ ・ (5)
-ωX = -A ・ ω ・ sin (ω ・ t) ・ ・ ・ (6)

  According to the rotation angle detection device 20 of the first embodiment described above, the RD converter 34 calculates the angular velocity ω, (−ω) of the resolver 22 from the digital values of the sin signal X and the cos signal Y, and the calculator 36. The arithmetic unit 36 uses the input digital values to calculate the time differential values dX / dt and dY / dt of the sin signal X and the cos signal Y, the product ωY of the cos signal Y and the angular velocity ω, and sin. The product -ωX of the signal X and the angular velocity (−ω) is calculated, the time differential value dX / dt and the product ωY are compared, and when the time differential value dX / dt and the product ωY are different, the sin signal XY is It is determined that an abnormality has occurred, the time differential value dY / dt is compared with the product (−ωX), and when the time differential value dY / dt and the product (−ωX) are different, an abnormality occurs in the cos signal Y. It is determined that Accordingly, it is possible to suppress erroneous determination that the sin signal X and the cos signal Y are normal although there is an abnormality.

  FIG. 4 is a configuration diagram showing an outline of the configuration of the rotation angle detection device 220 as the second embodiment of the present invention. Similar to the rotation angle detection device 20, the rotation angle detection device 220 is configured as a device that detects the rotation angle of the rotation axis A of the motor M, and includes a resolver 222, a rotary encoder 223, a buffer amplifier 234, A computer 224, multiplication type D / A converters 236 and 238, differentiation circuits 240 and 242, and comparators 244 and 246 are provided.

  Since the resolver 222 has the same configuration as the resolver 22 described above, detailed description thereof is omitted. The resolver 222 outputs the sin signal X and the cos signal Y to the buffer amplifier 234.

  The buffer amplifier 234 converts the sin signal X from the resolver 222 into a digital value and outputs the digital value to the microcomputer 224, the multiplication type D / A converter 236, and the differentiating circuit 242. The buffer amplifier 234 converts the cos signal Y from the resolver 222 into a digital value and outputs the digital value to the microcomputer 224, the multiplying D / A converter 236, and the differentiating circuit 240.

  The rotary encoder 223 is configured as, for example, a known optical incremental rotary encoder in which a rotary plate having a slit is attached to a rotary shaft connected to a rotor of a motor. The rotary encoder 223 outputs an A-phase pulse signal and a B-phase pulse signal that are 90 degrees out of phase to the microcomputer 224.

  The microcomputer 224 is mainly configured by a CPU (not shown), and includes a ROM, a RAM, an input / output port, a communication port, etc. (not shown) in addition to the CPU. The microcomputer 224 counts the number of pulses of the A-phase pulse signal and the B-phase pulse signal from the rotary encoder 223, and generates a Z-phase pulse signal that rises only twice per two rotations of the rotary encoder 223 and the count result. Then, the resolver angle φ is calculated from the sin signal X and the cos signal Y from the buffer amplifier 234. The microcomputer 224 calculates and outputs the angular velocity ω of the resolver 22 and the angular velocity (−ω) obtained by multiplying the angular velocity ω by the value −1 from the Z-phase pulse signal and the count result.

  The multiplying D / A converter 236 calculates a product ωY of the cos signal Y and the angular velocity ω from the angular velocity ω from the microcomputer 224 and the digital value of the cos signal Y from the buffer amplifier 234 and outputs the product ωY to the comparator 244. Multiplication type D / A converter 238 calculates the product (−ωX) of sin signal X and angular velocity (−ω) from the angular velocity (−ω) from microcomputer 224 and the digital value of sin signal X from buffer amplifier 234. And output to the comparator 246.

  The differentiating circuit 240 calculates a time differential value dX / dt of the sin signal X from the digital value of the sin signal X input from the buffer amplifier 234 and outputs it to the comparator 244. The differentiation circuit 242 outputs the time differential value dY / dt of the cos signal Y to the comparator 246 from the digital value of the cos signal Y input from the buffer amplifier 234.

  The comparator 244 compares the product ωY input from the multiplication type D / A converter 236 with the time differential value dX / dt input from the differentiation circuit 240. When the time differential value dX / dt is equal to the product ωY, it is determined that the sin signal X is normal, and a signal indicating that the sin signal X is normal is output as the signal Rsin. When the time differential value dX / dt and the product ωY are different, it is determined that an abnormality has occurred in the sin signal X, and a signal indicating that an abnormality has occurred in the sin signal X is output as the signal Rsin. As described above, when the sin signal X is normal, the time differential value dX / dt is equal to the product ωY, and when an abnormality occurs in the sin signal X, the time differential value dX / dt and the product ωY are different from each other. Become. Therefore, by comparing the product ωY input from the multiplication type D / A converter 236 and the time differential value dX / dt input from the differentiating circuit 240, the sin signal X is normal despite an abnormality. It can suppress misjudging that it is.

  The comparator 246 compares the product (−ωX) input from the multiplication type D / A converter 238 with the time differential value dY / dt input from the differentiating circuit 242 and outputs a signal Rcos indicating the comparison result. When the time differential value dY / dt is equal to the product (−ωX), it is determined that the cos signal Y is normal, and a signal indicating that the cos signal Y is normal is output as the signal Rcos. When the time differential value dY / dt is different from the product (−ωX), it is determined that an abnormality has occurred in the cos signal Y, and a signal indicating that an abnormality has occurred in the cos signal Y is output as the signal Rcos. . As described above, when the cos signal Y is normal, the time differential value dY / dt is equal to the product (−ωX), and when the signal fixation abnormality occurs in the cos signal Y, the time differential value dY / dt and the product ( -ΩX) is a different value. Therefore, by comparing the time differential value dY / dt and the product (−ωX), it is possible to suppress erroneous determination that the cos signal Y is normal although the cos signal Y is abnormal.

  In the rotation angle detector 220 of the second embodiment described above, the microcomputer 224 calculates the angular velocity ω, (−ω) from the output of the rotary encoder 223 and outputs it to the multiplying D / A converters 236, 238, The multiplication type D / A converter 236 calculates the product ωY of the cos signal Y and the angular velocity ω, the differentiation circuit 240 calculates the time differential value dX / dt of the sin signal X, and the comparator 244 calculates the product ωY and the time. The differential value dX / dt is compared, and when the time differential value dX / dt and the product ωY are different, it is determined that an abnormality has occurred in the sin signal X. The multiplication type D / A converter 238 calculates the product (−ωX) of the sin signal X and the angular velocity (−ω), the differentiation circuit 242 calculates the time differential value dY / dt of the cos signal Y, and the comparator 246. Compares the product (−ωX) with the time differential value dY / dt, and determines that an abnormality has occurred in the cos signal Y when the time differential value dY / dt and the product (−ωY) are different. Accordingly, it is possible to suppress erroneous determination that the sin signal X and the cos signal Y are normal although there is an abnormality.

  In the rotation angle detection device 220 of the second embodiment, the angular velocity ω, (−ω) of the resolver 222 is calculated based on the A-phase pulse signal and the B-phase pulse signal from the rotary encoder 223. And the microcomputer 224 may be omitted, and the angular velocity ω, (−ω) may be calculated from the sin signal X and the cos signal Y from the resolver 222.

  In the rotation angle detection devices 20 and 220 of the first and second embodiments, the resolvers 22 and 222 are attached to the rotation axis A of the motor M. The resolver 22 and 222 are attached to the rotation axis A of the motor M. It is not limited to what is attached, and it does not matter as long as it is attached to a rotating rotating shaft.

  In the first and second embodiments, the present invention relates to a rotation angle detection device 20 including a resolver 22 and a microcomputer 30, a resolver 222, a buffer amplifier 234, a rotary encoder 223, a microcomputer 224, An example applied to a rotation angle detection device 220 including multiplication type D / A converters 236 and 238, differentiation circuits 240 and 242, and comparators 244 and 246 is illustrated. However, the present invention is not limited to such a configuration, and a resolver 322, an angular velocity calculator (RD converter) 324, a differential calculator 326, and a multiplication are exemplified as illustrated in the rotation angle detection device 320 of the modified example of FIG. As long as it has the calculator 328 and the comparison calculator 330, it does not matter. In the rotation angle detection device 320 of the modified example, the resolver 322 has the same configuration as the resolvers 22 and 222. The angular velocity calculator (RD converter) 324 calculates the resolver angle φ and the angular velocity ω, (−ω) using the sin signal X and the cos signal Y from the resolver 322. The differential calculator 326 calculates time differential values dX / dt and dY / dt of the sin signal X and the cos signal Y from the resolver 322. The multiplication calculator 328 is the product of the product ωY of the cos signal Y from the resolver 322 and the angular velocity ω from the angular velocity calculator 324, and the product of the sin signal X from the resolver 322 and the angular velocity (−ω) from the angular velocity calculator 324. (−ωX) is calculated. The comparison computing unit 330 compares the time differential value dX / dt and the product ωY, compares the time differential value dY / dt and the product (−ωX), and when the time differential value dX / dt and the product ωY are different. It is determined that an abnormality has occurred in the sin signal X, and it is determined that an abnormality has occurred in the cos signal Y when the time differential value dY / dt differs from the product (−ωX). In the rotation angle detection device 320 of the modified example, the differential calculator 326, the multiplication calculator 328, and the comparison calculator 330 are configured by hardware, but the differential calculator 326, the multiplication calculator 328, the comparison calculator 230, The same function may be configured by software.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the first embodiment, the resolver 22 corresponds to a “resolver”, the AD converter 32 and the RD converter 34 correspond to a “resolver digital converter” and a “first calculation unit”, and the calculator 36 is an “abnormality determination device”. , “Second calculation unit”, “third calculation unit”, and “determination unit”. In the second embodiment, the resolver 222 corresponds to a “resolver”, the microcomputer 224 and the buffer amplifier 234 correspond to a “resolver digital converter”, the differentiating circuits 240 and 242 correspond to a “second arithmetic unit”, Multiplication type D / A converters 236 and 238 correspond to a “third arithmetic unit”, and comparators 244 and 246 correspond to a “determination unit”.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is the same as that of the embodiment described in the column of means for solving the problem. Therefore, the elements of the invention described in the column of means for solving the problems are not limited. In other words, the interpretation of the invention described in the column of means for solving the problem should be made based on the description of the column, and the examples are those of the invention described in the column of means for solving the problem. It is only a specific example.

  As mentioned above, although the form for implementing this invention was demonstrated using the Example, this invention is not limited at all to such an Example, In the range which does not deviate from the summary of this invention, it is with various forms. Of course, it can be implemented.

  The present invention can be used in the manufacturing industry of rotation angle detection devices.

  20, 220, 320 Rotation angle detection device, 22, 222, 322 Resolver, 30, 224 Microcomputer, 32 AD converter, 34 Resolver digital converter (RD converter), 36 arithmetic unit, M motor, A rotating shaft, 124 rotor, 125 excitation coil, 126, 127 output coil, 128 stator, 223 rotary encoder, 234 buffer amplifier, 236, 238 multiplication type D / A converter, 240, 242 differentiation circuit, 244, 246 comparator, 324 angular velocity calculator, 326 differentiation calculation , 328 multiplication operation unit, 330 comparison operation unit.

Claims (1)

A resolver attached to the rotating shaft;
A resolver digital converter that converts a sin signal and a cos signal from the resolver into digital values, and calculates a rotation angle of the rotation shaft from the digital values;
An abnormality determination device for determining whether an abnormality has occurred in the sin signal or the cos signal;
A rotation angle detection device comprising:
The resolver digital converter is:
A first calculation unit for calculating an angular velocity of the rotating shaft;
Have
The abnormality determination device is
A second calculation unit for calculating a time differential value of the sin signal and a time differential value of the cos signal;
A third calculation unit for calculating a first multiplication value obtained by multiplying the calculated angular velocity by the cos signal and a second multiplication value obtained by multiplying the calculated angular velocity by a value −1 and the sin signal;
The time differential value of the sin signal is compared with the first multiplication value, and when the time differential value of the sin signal and the first multiplication value do not match, it is determined that an abnormality has occurred in the sin signal, Judgment by comparing the time differential value of the cos signal with the second multiplication value and determining that an abnormality has occurred in the cos signal when the time differential value of the cos signal does not match the second multiplication value And
Having
Rotation angle detection device.

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