JP6652075B2 - Rotation angle detector - Google Patents

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 kind of rotation angle detection device, one provided with a resolver and a resolver digital converter (R / D converter) has been proposed (for example, see 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 device, the abnormality of the sin signal and the cos signal is detected by using the fact that the sum of the squares of the sin signal and the cos signal from the resolver has a value of 1.

JP 2008-122216 A

  However, in the rotation angle detection device described above, 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 the squares of the sin signal and the cos signal becomes the value 1 It may be. In this case, it is erroneously determined that the signal is normal even though the sin signal and the cos signal are abnormal.

  A main object of the rotation angle detection device of the present invention is to suppress erroneous determination that the sine signal and the cos signal from the resolver are normal despite the occurrence of an abnormality.

  The rotation angle detecting device of the present invention employs the following means in order to achieve the above-mentioned main object.

The rotation angle detection device of the present invention
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 axis from the digital values;
An abnormality determination device that determines whether an abnormality has occurred in the sin signal or the cos signal;
A rotation angle detection device comprising:
The resolver digital converter,
A first calculation unit for calculating the angular velocity of the rotating shaft;
Has,
The abnormality determination device,
A second calculator for calculating a time differential value of the sin signal and a time differential value of the cos signal;
A third calculator for calculating a first multiplied value obtained by multiplying the calculated angular velocity by the cos signal and a second multiplied value obtained by multiplying the calculated angular velocity by a value -1 and the sin signal;
Comparing the time derivative of the sine signal with the first multiplied value, and when the time derivative of the sine signal does not match the first multiplied value, determines that an abnormality has occurred in the sine signal; The time differential value of the cos signal is compared with the second multiplied value, and when the time differential value of the cos signal does not match the second multiplied value, it is determined that the cos signal is abnormal. Department and
Having,
That is the gist.

  In the rotation angle detecting device according to the present invention, the first calculation unit of the resolver digital converter calculates the angular velocity from the sine signal and the cos signal from the resolver. The second arithmetic 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 arithmetic unit calculates the first multiplied value obtained by multiplying the calculated angular velocity by the cos signal and calculates the first multiplied value. A second multiplied value is calculated by multiplying the calculated angular velocity by the value -1 and the sin signal. The abnormality determining unit compares the differential value of the sin signal with the first multiplied 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 multiplied value. When the sin signal is normal, the time derivative of the sin signal is equal to the first multiplied value. When an abnormality occurs in which the sin signal becomes a constant value (a value that does not change with respect to 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 multiplied value. It may be. Accordingly, the time differential value of the sin signal is compared with the first multiplied value, and when the time differential value of the sin signal does not match the first multiplied value, it is determined that an abnormality has occurred in the sin signal. Can be suppressed from being erroneously determined that the sin signal is normal when an error occurs in which the constant becomes a constant value. When the cos signal is normal, the time differential value of the cos signal is equal to the second multiplied value. When an abnormality occurs in which the cos signal becomes a constant value (a value that does not change with time), the time differential value of the cos signal becomes 0, and the time differential value of the cos signal and the second multiplied value become different values. . Therefore, the time differential value of the cos signal is compared with the second multiplied value, and when the time differential value of the cos signal does not match the second multiplied value, it is determined that an abnormality has occurred in the cos signal. Can be suppressed from being erroneously determined that the cos signal is normal when there is an abnormality in which is a constant value. As a result, it is possible to suppress erroneous determination that the sine signal and the cos signal from the resolver are normal despite the occurrence of an abnormality.

FIG. 1 is a configuration diagram schematically illustrating a configuration of a rotation angle detection device 20 according to a first embodiment of the present invention. FIG. 4 is an explanatory diagram for explaining a state in which a resolver 22 is attached to a rotating shaft A connected to a rotor of a motor M. FIG. 9 is an explanatory diagram illustrating an example of a temporal change of output signals of output coils 126 and 127. FIG. 9 is a configuration diagram schematically illustrating a configuration of a rotation angle detection device 220 as a second embodiment of the present invention. It is a block diagram showing the outline of the composition of rotation angle detector 320 of a modification.

  Next, an embodiment for carrying out the present invention will be described using an embodiment.

  FIG. 1 is a configuration diagram schematically showing 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 a rotating shaft A connected to a rotor of the motor M. The rotation angle detection device 20 is configured as, for example, 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 rotation axis A, and a rotor 124 as a magnetic body that rotates integrally with the rotation axis A, and an alternating current having a constant frequency as an excitation signal is applied from an oscillation circuit (not shown). And a stator 128 as a magnetic body including 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 a 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 a change in the gap between the rotor 124 and the stator 128 caused by the rotation of the elliptical rotor 124, and as shown in FIG. Sometimes, the signals have a sine wave shape and a cosine wave shape, respectively (hereinafter, a signal having a sine wave shape is referred to as a "sin signal X" and a signal having a cosine wave shape is referred to as a "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 “the sin signal X and the cos signal Y”. In the 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, in addition to the CPU, an AD converter 32, a resolver digital converter (hereinafter, referred to as an “RD converter”) 34, and a calculator 36. The microcomputer 30 further includes a ROM and a RAM (not shown), an input / output port, a communication port, and the like.

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

  The RD converter 34 calculates a 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 the resolver angle φ, the angular velocity ω, and the angular velocity (−ω) obtained by multiplying the angular velocity ω by a value −1.

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

  In the rotation angle detecting device 20 thus configured, when the sine 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 sine signal X and the cos signal Y into digital values. And outputs it to the RD converter 34. The RD converter 34 having input the digital values of the sin signal X and the cos signal Y calculates and outputs the rotation angle φ of the resolver 22 (resolver angle, that is, the rotation angle of the rotation axis A) φ from the sin signal X and the cos signal Y. I do.

  Next, the operation of the rotation angle detecting device 20 configured as described above, particularly, the operation for determining whether or not the sin signal X and the cos signal Y from the resolver 22 are abnormal will be described.

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

  The RD converter 34 to which the digital values have been input calculates the angular velocities ω, (−ω) of the resolver 22 from the respective digital values, and outputs the results 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 and (−ω) of the resolver 22 are input, uses the digital values of the sin signal X and the cos signal Y to generate the sin signal X and the cos signal Y. , 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 arithmetic unit 36 compares the time differential value dX / dt with the product ωY, and outputs a signal Rsin indicating the comparison result. 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, and the time differential value dX / dt Is different from the product ωY, it is determined that an abnormality (for example, an abnormality that does not change with time (signal fixation abnormality) or the like) occurs in the sin signal X, and an abnormality occurs in the sin signal X as the signal Rsin. Output a signal indicating that Here, the reason why it is possible to determine whether an abnormality has occurred in the sin signal X by comparing the time differential value dX / dt with 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 above equations (1) and (2). Therefore, when the sin signal X is normal, the time differential value dX / dt is equal to the product ωY. When an abnormality occurs in the sin signal X, the time differential value dX / dt becomes a constant value at a value of 0, and the time differential value dX / dt and the product ωY sometimes become different values. Therefore, by comparing the time differential value dX / dt with the product ωY, it is possible to determine whether or not the sin signal X is abnormal. As described above, by comparing the time differential value dX / dt and the product ωY to determine whether or not the sin signal X is abnormal, the sin signal X is normal despite the abnormality. It is possible to suppress erroneous determination that there is.

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

  The arithmetic unit 36 compares the time differential value dY / dt and the product (−ωX), and when the time differential value dY / dt and the product (−ωX) are equal, determines that the cos signal Y is normal. , A signal indicating that the cos signal Y is normal is output as the signal Rcos, and when the time differential value dY / dt and the product (−ωX) are different from each other, the cos signal Y has an abnormality (for example, abnormal signal fixation). It is determined that the error has occurred, and a signal indicating that an abnormality has occurred in the cos signal Y is output as the signal Rcos. 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 above equations (1) and (2). When the cos signal Y is normal, the time differential value dY / dt is equal to the product (−ωX). When the cos signal Y has a signal sticking abnormality, the time differential value dY / dt becomes 0, and the time differential value dY / dt becomes 0. The value dY / dt and the product (−ωX) are different values. Therefore, by comparing the time differential value dY / dt and the product (−ωX), it can be determined whether or not the cos signal Y is abnormal. This can prevent erroneous determination that the cos signal Y is normal despite the occurrence of an abnormality.

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

  According to the rotation angle detecting device 20 of the first embodiment described above, the RD converter 34 calculates the angular velocities ω, (−ω) of the resolver 22 from the digital values of the sine signal X and the cos signal Y, and calculates 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 is compared with the product ωY, and when the time differential value dX / dt and the product ωY are different, the sin signal XY is obtained. It is determined that an abnormality has occurred, and the time differential value dY / dt is compared with the product (−ωX). 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 there is. Thus, it is possible to suppress erroneous determination that the sine signal X and the cos signal Y are normal despite the occurrence of an abnormality.

  FIG. 4 is a configuration diagram schematically showing a configuration of a rotation angle detection device 220 as a second embodiment of the present invention. The rotation angle detection device 220 is configured as a device for detecting the rotation angle of the rotation axis A of the motor M, similarly to the rotation angle detection device 20, and includes a resolver 222, a rotary encoder 223, a buffer amplifier 234, and a microcontroller. It includes a computer 224, multiplying D / A converters 236 and 238, differentiating circuits 240 and 242, and comparators 244 and 246.

  Since the resolver 222 has the same configuration as the resolver 22 described above, detailed description will be 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 sine signal X 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 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 whose phases are shifted from each other by 90 degrees to the microcomputer 224.

  The microcomputer 224 mainly includes a CPU (not shown), and includes a ROM, a RAM, an input / output port, a communication port, and the like (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 for every two rotations of the rotary encoder 223 and a 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 an angular velocity ω of the resolver 22 and an angular velocity (−ω) obtained by multiplying the angular velocity ω by a 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 result to the comparator 244. The multiplying D / A converter 238 calculates the product (−ωX) of the sin signal X and the angular velocity (−ω) from the angular velocity (−ω) from the microcomputer 224 and the digital value of the sin signal X from the buffer amplifier 234. And outputs it 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 the result to the comparator 244. The differentiating circuit 242 outputs a 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 multiplying D / A converter 236 with the time differential value dX / dt input from the differentiating circuit 240. When the time differential value dX / dt is equal to the product ωY, it determines that the sin signal X is normal, and outputs a signal indicating that the sin signal X is normal as the signal Rsin. When the time differential value dX / dt is different from the product ωY, 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 a signal Rsin. As described above, when the sin signal X is normal, the time differential value dX / dt becomes equal to the product ωY, and when the sin signal X becomes abnormal, the time differential value dX / dt and the product ωY become different values. Become. Therefore, by comparing the product ωY input from the multiplying D / A converter 236 with the time differential value dX / dt input from the differentiating circuit 240, it is possible to determine that the sine signal X is normal despite the occurrence of an abnormality. Erroneously determined to be.

  The comparator 246 compares the product (−ωX) input from the multiplying 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 derivative 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 and the product (-ωX) are different, it is determined that the cos signal Y is abnormal, and a signal indicating that the cos signal Y is abnormal is output as the signal Rcos. . As described above, when the cos signal Y is normal, the time differential value dY / dt becomes equal to the product (−ωX), and when the cos signal Y has a signal sticking abnormality, the time differential value dY / dt and the product (−ωX) are obtained. −ωX). 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 despite the occurrence of an abnormality in the cos signal Y.

  In the rotation angle detecting device 220 of the second embodiment described above, the microcomputer 224 calculates the angular velocities ω, (−ω) from the output of the rotary encoder 223, and outputs the calculated angular velocities to the multiplying D / A converters 236, 238. The multiplying D / A converter 236 calculates the product ωY of the cos signal Y and the angular velocity ω, the differentiating 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 is different from the product ωY, it is determined that the sin signal X is abnormal. The multiplying D / A converter 238 calculates a product (−ωX) of the sin signal X and the angular velocity (−ω), the differentiating circuit 242 calculates a time differential value dY / dt of the cos signal Y, and a comparator 246. Compares the product (−ωX) with the time differential value dY / dt, and when the time differential value dY / dt and the product (−ωY) are different, determines that the cos signal Y is abnormal. Thus, it is possible to suppress erroneous determination that the sine signal X and the cos signal Y are normal despite the occurrence of 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, 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, but the resolvers 22 and 222 are attached to the rotation axis A of the motor M. It is not limited to the one to be attached, but may be any 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 detecting device 20 including a resolver 22 and a microcomputer 30, a resolver 222, a buffer amplifier 234, a rotary encoder 223, a microcomputer 224, The example applied to a rotation angle detecting device 220 including multiplying D / A converters 236 and 238, differentiating circuits 240 and 242, and comparators 244 and 246 is illustrated. However, the present invention is not limited to such a configuration, and as illustrated in a rotation angle detection device 320 of a modified example in FIG. 5, a resolver 322, an angular velocity calculator (RD converter) 324, a differential calculator 326, Any configuration may be used as long as the configuration includes the arithmetic unit 328 and the comparison arithmetic unit 330. 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 the time differential values dX / dt and dY / dt of the sin signal X and the cos signal Y from the resolver 322. The multiplication operation unit 328 calculates the product ωY of the cos signal Y from the resolver 322 and the angular velocity ω from the angular velocity operation unit 324, and the product of the sin signal X from the resolver 322 and the angular velocity (−ω) from the angular velocity operation unit 324. (−ωX). The comparison calculator 330 compares the time differential value dX / dt with the product ωY and also compares the time differential value dY / dt with the product (−ωX). 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 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. In the rotation angle detection device 320 of the modified example, the differential operation unit 326, the multiplication operation unit 328, and the comparison operation unit 330 are configured by hardware, but the differential operation unit 326, the multiplication operation unit 328, the comparison operation unit 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 section 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 operation unit”, and the operation unit 36 corresponds to an “abnormality determination device”. , "Second operation unit", "third operation unit", and "judgment 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 operation unit", The multiplying D / A converters 236 and 238 correspond to a “third operation unit”, and the 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 section of the means for solving the problem is as follows. This is merely an example for specifically describing a mode for carrying out the invention, and thus does not limit the elements of the invention described in the section of “Means for Solving the Problems”. That is, the interpretation of the invention described in the section of the means for solving the problem should be interpreted based on the description of the section, and the embodiment is not limited to the invention described in the section of the means for solving the problem. This is only a specific example.

  As described above, the embodiments for carrying out the present invention have been described using the embodiments. However, the present invention is not limited to these embodiments at all, and various forms may be provided without departing from the gist of the present invention. Of course, it can be implemented.

  INDUSTRIAL APPLICABILITY The present invention is applicable to a manufacturing industry of a rotation angle detection device and the like.

  20, 220, 320 rotation angle detecting 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 operation Unit, 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 axis from the digital values;
An abnormality determination device that determines whether an abnormality has occurred in the sin signal or the cos signal;
A rotation angle detection device comprising:
The resolver digital converter,
A first calculation unit for calculating the angular velocity of the rotating shaft;
Has,
The abnormality determination device,
A second calculator for calculating a time differential value of the sin signal and a time differential value of the cos signal;
A third calculator for calculating a first multiplied value obtained by multiplying the calculated angular velocity by the cos signal and a second multiplied value obtained by multiplying the calculated angular velocity by a value -1 and the sin signal;
Comparing the time derivative of the sine signal with the first multiplied value, and when the time derivative of the sine signal does not match the first multiplied value, determines that an abnormality has occurred in the sine signal; The time differential value of the cos signal is compared with the second multiplied value, and when the time differential value of the cos signal does not match the second multiplied value, it is determined that the cos signal is abnormal. Department and
Having,
Rotation angle detector.

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