JP5454390B2 - Rotation angle detector - Google Patents

Description

  The present invention calculates a rotation angle of a rotating body based on an output signal of the magnet provided on the rotating body, a magnetic detection unit that detects a change in magnetic flux emitted from the magnet due to the rotation of the rotating body, and the magnetic detection unit And a rotation angle detecting device including the calculating unit.

  Conventionally, as shown in Patent Document 1, for example, based on a magnet fixed to a rotating body, magnetic flux density detecting means for outputting a sine wave signal corresponding to the rotation angle of the rotating body, and an output signal of the magnetic flux density detecting means Thus, there has been proposed a rotation angle detection device including rotation angle calculation means for calculating the rotation angle of the rotating body. In this rotation angle detection device, the three magnetic flux density detection means are arranged so as to output three sine wave signals that are not in phase and opposite phase to each other. The above rotation angle calculation means sequentially selects two sine wave signals from the sine wave signals output from the three magnetic flux density detection means, and based on the selected two sine wave signals, the sine value and cosine for the rotation angle. Calculate the value. Next, the rotation angle calculation means calculates a rotation angle by calculating an arctangent based on the calculated sine value and cosine value, and determines whether the rotation angle is normal based on the sine value, cosine value, and rotation angle. Determine. Finally, the rotation angle calculation means outputs the rotation angle determined to be normal.

  According to the above configuration, even if one of the three magnetic flux density detection means fails, two of the calculated three rotation angles are abnormal, but the normal rotation angle is You can get one. In this way, even if one of the three magnetic flux density detection means fails, a normal rotation angle can be detected based on the sine wave signals of the remaining two magnetic flux density detection means. It has become.

JP 2008-286709 A

  By the way, as described above, the rotation angle detection device disclosed in Patent Document 1 detects the rotation angle based on two sine wave signals. Therefore, when two magnetic detectors out of the three magnetic flux density detectors (magnetic detectors) fail, only one sine wave signal can be obtained, so that the rotation angle cannot be detected. Arise.

  Therefore, in view of the above problems, the present invention has an object to provide a rotation angle detection device capable of detecting a rotation angle even if only an output signal of one magnetic detection unit can be obtained due to a failure. To do.

  In order to achieve the above-described object, the invention described in claim 1 includes a magnet provided in the rotating body, a magnetic detection unit that detects a change in magnetic flux generated from the magnet due to the rotation of the rotating body, and the magnetic detection. A rotation angle detector that calculates a rotation angle of a rotating body based on an output signal of the rotation unit, wherein the magnetism detection unit is arranged so that the phase difference of the output signal differs by 90 ° or 270 °. A first magnetic detection unit and a second magnetic detection unit that are provided apart from each other in the rotation direction, and the calculation unit generates a cosine wave signal based on the sine wave signal output from the first magnetic detection unit. A first generator for generating; a second generator for generating a sine wave signal based on a cosine wave signal output from the second magnetic detector; a sine wave signal for the first magnetic detector; and a second generator A first normal sine wave signal out of the first sine wave signals A selection unit; a second selection unit that outputs one normal cosine wave signal among the cosine wave signal of the second magnetic detection unit and the cosine wave signal of the first generation unit; and a sine output from the first selection unit And a calculation unit that calculates a rotation angle of the rotating body based on the wave signal and the cosine wave signal output from the second selection unit.

  Thus, according to the present invention, the first magnetic detection unit and the second magnetic detection unit are provided apart from each other in the rotation direction of the magnet so that the phase difference of the output signal differs by 90 ° or 270 °. A sine wave signal is output from the first magnetic detection unit, and a cosine wave signal is output from the second magnetic detection unit. Further, the calculation unit is based on the first generation unit that generates a cosine wave signal based on the sine wave signal output from the first magnetic detection unit, and on the basis of the cosine wave signal output from the second magnetic detection unit, A second generator for generating a sine wave signal.

  According to this, for example, even when the first magnetic detection unit fails, the cosine wave signal of the second magnetic detection unit and the sine wave signal of the second generation unit can be obtained as normal signals. On the contrary, even when the second magnetic detection unit fails, the sine wave signal of the first magnetic detection unit and the cosine wave signal of the first generation unit can be obtained as normal signals. Thus, even if only one output signal from the other magnetic detector can be obtained because one of the magnetic detectors has failed, two normal signals (sinusoidal waves) having a phase difference of 90 ° or 270 °. Signal and cosine wave signal). Therefore, the rotation angle can be detected by calculating these two signals in the calculation unit.

  The calculation unit includes a first selection unit that outputs one normal sine wave signal out of the sine wave signal of the first magnetic detection unit and the sine wave signal of the second generation unit, and the cosine of the second magnetic detection unit. And a second selection unit that outputs one normal cosine wave signal among the wave signal and the cosine wave signal of the first generation unit. According to this, failure determination of each magnetic detection unit can be performed based on the output signal of each magnetic detection unit or the output signal of each generation unit.

  The first selection unit outputs the sine wave signal of the first magnetic detection unit when the first selection unit determines that the first magnetic detection unit is operating normally, and detects the first magnetic detection unit. The second generation unit outputs a sine wave signal of the second generation unit when it is determined that the unit is out of order, and the second selection unit determines that the second magnetic detection unit is operating normally. A configuration is preferable in which the cosine wave signal of the first generation unit is output when the cosine wave signal of the magnetic detection unit is output and it is determined that the second magnetic detection unit is out of order.

  Since the output signal of the generation unit is a signal generated based on the output signal of the magnetic detection unit, the waveform may be disturbed compared to the output signal of the original magnetic detection unit. In contrast, in the second aspect of the invention, when the magnetic detection unit is normal, the output signal of the magnetic detection unit is input to the calculation unit. As a result, even when the magnetic detection unit is normal, the output signal of the generation unit is not input to the calculation unit, so that the detection accuracy of the rotation angle is prevented from being lowered.

  According to a third aspect of the present invention, the first selection unit determines the presence or absence of a failure of the first magnetic detection unit based on the sine wave signal of the first magnetic detection unit, and the second selection unit detects the second magnetic detection unit. The second selection unit determines whether or not the second magnetic detection unit has failed based on the cosine wave signal of the unit, and the first selection unit receives information from the second selection unit that the second magnetic detection unit has failed. The second magnetic detecting unit outputs a sine wave signal of the first magnetic detecting unit, and the second selecting unit detects the second magnetic detecting unit when information indicating that the first magnetic detecting unit is out of order is transmitted from the first selecting unit. The structure which outputs the cosine wave signal of a part is good.

  According to this, a 1st selection part determines the presence or absence of a failure of a 2nd magnetic detection part based on the cosine wave signal produced | generated by the 2nd production | generation part, and a 2nd selection part is produced | generated by the 1st production | generation part Compared with the configuration for determining the presence or absence of a failure of the first magnetic detection unit based on the sine wave signal, the failure determination of the magnetic detection unit is faster and the signal processing speed is faster.

  In addition, although the second magnetic detection unit is out of order, the sine wave signal of the second generation unit is prevented from being output from the first selection unit, and the first magnetic detection unit is out of order. Nevertheless, the cosine wave signal of the first generator is prevented from being output from the second selector. Thereby, it is suppressed that the detection accuracy of a rotation angle falls.

  According to a fourth aspect of the present invention, the first selection unit includes a first memory in which a specified value of the sine wave signal of the first magnetic detection unit is stored, and the specified value and the sine wave signal of the first magnetic detection unit. A first determination unit that determines whether or not the first magnetic detection unit is operating normally, and the second selection unit has a specified value of the cosine wave signal of the second magnetic detection unit A second determination unit that determines whether or not the second magnetic detection unit is operating normally based on the stored second memory and the specified value and the cosine wave signal of the second magnetic detection unit; Good configuration. According to this, by determining whether or not the amplitude of the signal output from each magnetic detection unit is a normal value, it is possible to determine whether or not there is a failure in each magnetic detection unit.

  According to a fifth aspect of the present invention, the first selection unit includes a third memory in which a predetermined value of a signal obtained by differentiating the sine wave signal of the first magnetic detection unit is stored, and the predetermined value and the first magnetic detection unit. A third determination unit that determines whether or not the first magnetic detection unit is operating normally based on a signal obtained by differentiating the sine wave signal, and the second selection unit includes the second magnetic detection unit. The second magnetic detection unit normally operates on the basis of the fourth memory in which the prescribed value of the signal obtained by differentiating the cosine wave signal is stored and the signal obtained by differentiating the prescribed value and the cosine wave signal of the second magnetic detection unit. A configuration having a fourth determination unit that determines whether or not the device is operating is preferable. According to this, by determining whether or not the waveform of the signal output from each magnetic detection unit is normal, it is possible to determine whether or not there is a failure in each magnetic detection unit.

The first selection unit may determine whether the first magnetic detection unit is operating normally and the first magnetic detection unit sine wave signal and the second generation unit sine wave signal. And a second selection unit for determining whether the second magnetic detection unit is operating normally and the cosine wave signal of the second magnetic detection unit and the first generation unit. A configuration having a second comparison unit that compares the cosine wave signal is preferable. According to this, it is possible to determine whether or not there is a failure in each magnetic detection unit by determining whether the amplitude or waveform of the signal output from each magnetic detection unit is normal.

  Since the operational effects of the inventions according to claims 7 to 10 are the same as the operational effects of the invention according to any one of claims 1 to 5, the description thereof is omitted.

  The first generation unit generates a cosine wave signal by differentiating the sine wave signal of the first magnetic detection unit once, and the second generation unit includes the second magnetic detection unit. The sine wave signal is preferably generated by differentiating the cosine wave signal once and inverting the sign.

  When the output signal of the first magnetic detection unit is expressed as sin θ, the output signal of the second magnetic detection unit is cos θ. Therefore, the first generation unit outputs a value obtained by differentiating sin θ, cos θ, and the second generation unit outputs a value obtained by differentiating cos θ and inverting the sign (positive / negative), sin θ. Thus, a cosine wave signal corresponding to the output signal of the second magnetic detector is output from the first generator, and a sine wave signal corresponding to the output signal of the first magnetic detector is output from the second generator. Is output.

  The first generation unit generates a cosine wave signal by differentiating the sine wave signal of the first magnetic detection unit once, and the second generation unit includes the second magnetic detection unit. It is preferable to generate a sine wave signal by differentiating the cosine wave signal three times.

  As described above, when the output signal of the first magnetic detection unit is expressed as sin θ, the output signal of the second magnetic detection unit is cos θ. Therefore, the first generation unit outputs a value obtained by differentiating sin θ, cos θ, and the second generation unit outputs a value obtained by differentiating cos θ, differentiating −sin θ, and differentiating −cos θ, sin θ. . Thus, a cosine wave signal corresponding to the output signal of the second magnetic detector is output from the first generator, and a sine wave signal corresponding to the output signal of the first magnetic detector is output from the second generator. Is output.

  According to a thirteenth aspect of the present invention, it is preferable to have a notification unit that notifies the user of the presence or absence of a failure in each of the first magnetic detection unit and the second magnetic detection unit. According to this, the user can recognize the presence or absence of a failure of the rotation angle detection device. Further, the user can recognize whether or not the signal output from the rotation angle detection device is correct.

It is a top view for demonstrating the position of a magnet and a magnetic detection part. It is a block diagram which shows schematic structure of the rotation angle detection apparatus which concerns on 1st Embodiment. It is a block diagram for demonstrating the signal when a 1st magnetism detection part fails. It is a block diagram for demonstrating the signal when a 2nd magnetism detection part fails. It is a block diagram which shows schematic structure of the rotation angle detection apparatus which concerns on 2nd Embodiment. It is a block diagram for demonstrating the signal when a 1st magnetism detection part fails. It is a block diagram for demonstrating the signal when a 2nd magnetism detection part fails.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a plan view for explaining the positions of the magnet and the magnetic detection unit. FIG. 2 is a block diagram illustrating a schematic configuration of the rotation angle detection device according to the first embodiment. FIG. 3 is a block diagram for explaining a signal when the first magnetic detection unit fails. FIG. 4 is a block diagram for explaining a signal when the second magnetic detection unit fails. 2 to 4, the magnet 10 is omitted, and in FIGS. 3 and 4, failures and abnormalities are indicated by broken lines.

  The rotation angle detection device 100 includes a magnet 10, a magnetic detection unit 30, and a calculation unit 50 as main parts. As shown in FIG. 1, a magnetic detection unit 30 is disposed near the magnet 10, and a magnetic flux generated from the magnet 10 is applied to the magnetic detection unit 30. Further, as shown in FIG. 2, the magnetic detection unit 30 is electrically connected to the calculation unit 50, and an output signal of the magnetic detection unit 30 depending on the magnetic field of the magnet 10 is input to the calculation unit 50. It has become. The rotation angle detection apparatus 100 according to the present embodiment includes a notification unit 70. The notification unit 70 and the calculation unit 50 are electrically connected, and a signal including a failure determination of the magnetic detection unit 30 is notified. It is input to the unit 70. In the following, after describing each of the magnet 10, the magnetic detection unit 30, the calculation unit 50, and the notification unit 70, the calculation unit 50 that is a feature point of the rotation angle detection device 100 will be described in detail.

  The magnet 10 has at least one magnetic pole pair composed of an N pole and an S pole. The magnet 10 according to the present embodiment has one magnetic pole pair and has an annular shape. A cylindrical shaft 11 is inserted into a hole formed by the inner ring portion of the magnet 10 that forms an annular shape, and is fixed to the shaft 11 together with a rotor (not shown) made of a permanent magnet. The shaft 11 is rotated by a repulsive force between a magnetic flux generated from a field winding (not shown) arranged around the shaft 11 and a magnetic flux generated by the rotor described above. As the shaft 11 rotates, the magnet 10 also rotates, and a change in magnetic flux emitted from the magnet 10 due to this rotation is applied to the magnetic detection unit 30. The shaft 11 corresponds to the rotating body described in the claims.

  The magnetic detection unit 30 detects a change in magnetic flux emitted from the magnet 10 due to the rotation of the shaft 11. As shown in FIG. 1, the magnetic detection unit 30 includes a first magnetic detection unit 31 and a second magnetic detection unit 32 that are provided apart from each other in the rotation direction of the magnet 10 so that the phase difference of the output signal differs by 90 °. And have. Each of the magnetic detectors 31 and 32 is a magnetoresistor that outputs a waveform signal for one cycle when the magnet 10 rotates by an electrical angle (an angle obtained by dividing the angle at which the shaft 11 rotates once by the magnetic pole pair of the magnet 10). It is an element. If the angle around the shaft 11 is θ, a signal dependent on sin θ (hereinafter referred to as a sine wave signal S1) is output from the first magnetic detection unit 31, and a signal dependent on cos θ from the second magnetic detection unit 32. (Hereinafter referred to as cosine wave signal C1) is output.

  The calculation unit 50 calculates the rotation angle of the shaft 11 based on the output signal of the magnetic detection unit 30. The calculation unit 50 generates a cosine wave signal C2 corresponding to the cosine wave signal C1 based on the sine wave signal S1, and the sine corresponding to the sine wave signal S1 based on the cosine wave signal C1. A second generation unit 52 that generates the wave signal S2. Further, the calculation unit 50 outputs a normal sine wave signal of the sine wave signals S1 and S2, and one normal cosine wave signal of the cosine wave signals C1 and C2. Based on the second selection unit 54 to be output, the sine wave signal output from the first selection unit 53 and the cosine wave signal output from the second selection unit 54, the calculation unit 55 that calculates the rotation angle of the shaft 11. And having. The calculation unit 55 calculates the rotation angle of the shaft 11 by performing an arctangent calculation based on the input sine wave signal and cosine wave signal.

  The notification unit 70 functions to notify the user of the presence or absence of a failure in each of the magnetic detection units 31 and 32. As shown in FIG. 2, the notification unit 70 is electrically connected to determination units 57 and 59 to be described later, and the determination unit 57 and 59 includes an electric circuit including the presence / absence of a failure in each of the magnetic detection units 31 and 32. When a signal is output, this is notified to the user by voice or symbol.

  Next, the calculation unit 50 that is a feature point of the rotation angle detection device 100 will be described in detail. As shown in FIG. 2, the output signal (sine wave signal S1) of the first magnetic detection unit 31 is input to the first generation unit 51 and the first selection unit 53, and the output signal of the second magnetic detection unit 32 ( The cosine wave signal C1) is input to the second generator 52 and the second selector 54. The first generation unit 51 generates the cosine wave signal C2 by differentiating the sine wave signal S1 once, and the second generation unit 52 differentiates the cosine wave signal C1 once and then changes the sign (positive / negative). By inverting, a sine wave signal S2 is generated. The cosine wave signal C2 generated by the first generation unit 51 is input to the second selection unit 54, and the sine wave signal S2 generated by the second generation unit 52 is input to the first selection unit 53. As described above, the sine wave signals S 1 and S 2 are input to the first selection unit 53, and the cosine wave signals C 1 and C 2 are input to the second selection unit 54.

  The first selection unit 53 includes a first storage unit 56 that stores a prescribed value of the sine wave signal S1 and a prescribed value of a signal obtained by differentiating the sine wave signal S1, and the prescribed value and the sine wave signal S1. And a first determination unit 57 that determines whether or not the first magnetic detection unit 31 is operating normally. The first determination unit 57 according to the present embodiment functions to compare the sine wave signals S1 and S2, and also functions as the first comparison unit described in the claims. The first determination unit 57 has the functions of the first determination unit and the third determination unit described in the claims, and the first storage unit 56 includes the first memory and the first determination unit described in the claims. It has the functions of each of the three memories.

  When the sine wave signals S1 and S2 are input, the first determination unit 57 first compares the sine wave signal S2 with the sine wave signal S1 using the sine wave signal S2 as a reference signal. Here, if the waveforms match, it is determined that the sine wave signal S1 is normal, the first magnetic detection unit 31 is normal, the sine wave signal S1 is output to the calculation unit 55, and the first magnetic detection is performed. Information that the unit 31 is normal is output to the notification unit 70.

  When the waveforms do not match, the first determination unit 57 extracts the specified value of the sine wave signal S1 and the specified value of the signal obtained by differentiating the sine wave signal S1 from the first storage unit 56, and uses these specified values. As a reference value, the amplitude and waveform of the sine wave signal S1 are determined. Here, when the first determination unit 57 determines that the sine wave signal S1 is normal and the first magnetic detection unit 31 is normal, the sine wave signal S1 is output to the calculation unit 55 and the first The information that the 1 magnetic detection unit 31 is normal is output to the notification unit 70. On the other hand, when the first determination unit 57 determines that the sine wave signal S1 is not normal and the first magnetic detection unit 31 is out of order, the sine wave signal S2 is output to the calculation unit 55. At the same time, information that the first magnetic detection unit 31 is out of order is output to the notification unit 70.

  The second selection unit 54 stores the specified value of the cosine wave signal C1 and the specified value of the signal obtained by differentiating the cosine wave signal C1, the second storage unit 58, and the specified value and the cosine wave signal C1. And a second determination unit 59 that determines whether or not the second magnetic detection unit 32 is operating normally. The second determination unit 59 according to the present embodiment functions to compare the cosine wave signals C1 and C2, and also functions as the second comparison unit described in the claims. The second determination unit 59 has the functions of the second determination unit and the fourth determination unit described in the claims, and the second storage unit 58 includes the second memory and the second determination unit described in the claims. It has the functions of each of the four memories.

  When the cosine wave signals C1 and C2 are input, the second determination unit 59 first compares the cosine wave signal C2 with the cosine wave signal C1 using the cosine wave signal C2 as a reference signal. Here, if the waveforms match, it is determined that the cosine wave signal C1 is normal, the second magnetic detection unit 32 is normal, the cosine wave signal C1 is output to the calculation unit 55, and the second magnetic detection is performed. Information that the unit 32 is normal is output to the notification unit 70.

  If the waveforms do not match, the second determination unit 59 extracts the specified value of the cosine wave signal C1 and the specified value of the signal obtained by differentiating the cosine wave signal C1 from the first storage unit 56, and uses these specified values. As a reference value, the amplitude and waveform of the cosine wave signal C1 are determined. Here, if the second determination unit 59 determines that the cosine wave signal C1 is normal and the second magnetic detection unit 32 is normal, the cosine wave signal C1 is output to the calculation unit 55, and the first 2 Information indicating that the magnetic detection unit 32 is normal is output to the notification unit 70. On the other hand, when the second determination unit 59 determines that the cosine wave signal C1 is not normal and the second magnetic detection unit 32 is out of order, the cosine wave signal C2 is output to the calculation unit 55. At the same time, information that the second magnetic detection unit 32 is out of order is output to the notification unit 70.

  Although not shown, the first determination unit 57 and the second determination unit 59 are electrically connected. When the first determination unit 57 determines that the first magnetic detection unit 31 is out of order, information indicating that the first magnetic detection unit 31 is out of order is output to the second determination unit 59. When this information is received by the second determination unit 59, the second determination unit 59 outputs the cosine wave signal C1 to the calculation unit 55 without performing the above-described failure determination. When the second determination unit 59 determines that the second magnetic detection unit 32 is out of order, information indicating that the second magnetic detection unit 32 is out of order is output to the first determination unit 57. The When this information is received by the first determination unit 57, the first determination unit 57 outputs the sine wave signal S1 to the calculation unit 55 without performing the above-described failure determination.

  Moreover, although not shown in figure, the 1st production | generation part 51 and the 1st determination part 57 are electrically connected, and the 2nd production | generation part 52 and the 2nd determination part 59 are electrically connected. Then, the first generation unit 51 outputs a signal obtained by differentiating the sine wave signal S1 once to the first determination unit 57, and the second generation unit 52 generates a signal obtained by differentiating the cosine wave signal C1 once. 2 is output to the determination unit 59. Based on the signal output from the first generation unit 51 and the specified value of the signal obtained by differentiating the sine wave signal S1 stored in the first storage unit 56, the first determination unit 57 calculates the sine wave signal S1. Determine the waveform. Based on the signal output from the second generation unit 52 and the specified value of the signal obtained by differentiating the cosine wave signal C1 stored in the second storage unit 58, the second determination unit 59 determines the cosine wave signal C1. Determine the waveform.

  Furthermore, the notification unit 70 according to the present embodiment is electrically connected to a control unit (not shown) that controls the calculation unit 50. When it is determined by the first determination unit 57 that the first magnetic detection unit 31 is out of order, the information is output to the control unit via the notification unit 70, and the first generation unit 51 and the first selection unit 53, respectively. Is stopped. When the second determination unit 59 determines that the second magnetic detection unit 32 is out of order, the information is output to the control unit via the notification unit 70, and the second generation unit 52 and the second selection unit Each drive of 54 is stopped. When it is determined that each of the magnetic detection units 31 and 32 is out of order, the information is output to the control unit via the notification unit 70, and the driving of the calculation unit 50 is stopped.

  Next, the effect of the rotation angle detection apparatus 100 according to the present embodiment will be described. As described above, the magnetic detection unit 30 includes the first magnetic detection unit 31 that outputs the sine wave signal S1 and the second magnetic detection unit 32 that outputs the cosine wave signal C1. The calculation unit 50 corresponds to the sine wave signal S1 based on the first generation unit 51 that generates the cosine wave signal C2 corresponding to the cosine wave signal C1 based on the sine wave signal S1, and the cosine wave signal C1. And a second generation unit 52 that generates a sine wave signal S2 to be generated.

  According to this, for example, as shown in FIG. 3, even when the first magnetic detection unit 31 breaks down and the signals S <b> 1 and C <b> 2 become abnormal, The cosine wave signal C1 and the sine wave signal S2 of the second generator 52 can be obtained. On the contrary, as shown in FIG. 4, even when the second magnetic detection unit 32 fails and the signals C1 and S2 become abnormal, the sine of the first magnetic detection unit 31 is regarded as a normal signal. The wave signal S1 and the cosine wave signal C2 of the first generator 51 can be obtained. Thus, even if only one of the output signals of the other magnetic detection unit can be obtained because one of the magnetic detection units has failed, two normal signals (a sine wave signal and a cosine signal) that differ in phase by 90 ° are obtained. Wave signal). Therefore, the rotation angle can be detected by calculating these two signals by the calculation unit 55.

  Further, the calculation unit 50 outputs a normal sine wave signal of the sine wave signals S1 and S2, and one normal cosine wave signal of the cosine wave signals C1 and C2. A second selection unit 54 for outputting. According to this, based on the output signals S1 and C1 of the magnetic detection units 31 and 32 or the output signals S2 and C2 of the generation units 51 and 52, it is possible to determine the failure of each of the magnetic detection units 31 and 32.

  The first selection unit 53 includes a first storage unit 56 that stores a prescribed value of the sine wave signal S1 and a prescribed value of a signal obtained by differentiating the sine wave signal S1, and the prescribed value and the sine wave signal S1. And a first determination unit 57 that determines whether or not the first magnetic detection unit 31 is operating normally. According to this, the 1st determination part 57 takes out a regulation value from the 1st memory | storage part 56, and uses this regulation value as a reference value, and determines the amplitude and waveform of sine wave signal S1, and is 1st magnetic detection. The presence or absence of a failure of the unit 31 can be determined.

  The second selection unit 54 stores the specified value of the cosine wave signal C1 and the specified value of the signal obtained by differentiating the cosine wave signal C1, the second storage unit 58, and the specified value and the cosine wave signal C1. And a second determination unit 59 that determines whether or not the second magnetic detection unit 32 is operating normally. According to this, the second determination unit 59 takes out the specified value from the second storage unit 58 and determines the amplitude and waveform of the cosine wave signal C1 using the specified value as a reference value, thereby detecting the second magnetic detection. The presence or absence of a failure of the unit 32 can be determined.

  The first determination unit 57 functions to compare the sine wave signals S1 and S2, and the first determination unit 57 functions to compare the sine wave signals S1 and S2. According to this, the first determination unit 57 compares the sine wave signal S2 with the sine wave signal S1 using the sine wave signal S2 as a reference signal, and the second determination unit 59 uses the cosine wave signal C2 as a reference signal. By comparing the cosine wave signal C2 and the cosine wave signal C1, it is possible to determine the presence or absence of a failure in each of the magnetic detection units 31 and 32.

  Since the output signals S2 and C2 of the generation units 51 and 52 are signals generated based on the output signals S1 and C1 of the magnetic detection units 31 and 32, the output signals S1 and C1 of the original magnetic detection units 31 and 32 are generated. There is a possibility that the waveform is disturbed. On the other hand, in this embodiment, the first determination unit 57 outputs the sine wave signal S1 of the first magnetic detection unit 31 when it is determined that the first magnetic detection unit 31 is operating normally. The second determination unit 59 outputs the cosine wave signal C1 of the second magnetic detection unit 32 when it is determined that the second magnetic detection unit 32 is operating normally. According to this, even when the magnetic detection units 31 and 32 are normal, the output signals S2 and C2 of the generation units 51 and 52 are not input to the calculation unit 55, so that the rotation angle detection accuracy is lowered. It is suppressed.

  The first determination unit 57 outputs the sine wave signal S1 of the first magnetic detection unit 31 when information indicating that the second magnetic detection unit 32 is out of order is transmitted from the second determination unit 59. 2 determination part 59 outputs the cosine wave signal C1 of the 2nd magnetic detection part 32, when the information that the 1st magnetic detection part 31 has failed from the 1st determination part 57 is transmitted. According to this, the sine wave signal S2 of the second generation unit 52 is prevented from being output from the first determination unit 57 even though the second magnetic detection unit 32 is out of order, and the first magnetic detection Although the unit 31 is out of order, the cosine wave signal C <b> 2 of the first generation unit 51 is suppressed from being output from the second determination unit 59. Thereby, it is suppressed that the detection accuracy of a rotation angle falls.

  The notification unit 70 notifies the user when an electric signal including the presence / absence of the failure of the magnetic detection units 31 and 32 is output from the determination units 57 and 59. According to this, the user can recognize whether there is a failure in the rotation angle detection device 100 and whether the signal output from the rotation angle detection device 100 is correct.

  The first generation unit 51 outputs a signal obtained by differentiating the sine wave signal S1 once to the first determination unit 57, and the second generation unit 52 determines a signal obtained by differentiating the cosine wave signal C1 once. Is output to the unit 59. Based on the signal output from the first generation unit 51 and the specified value of the signal obtained by differentiating the sine wave signal S1 stored in the first storage unit 56, the first determination unit 57 calculates the sine wave signal S1. Determine the waveform. The second determination unit 59 then generates a cosine wave signal based on the signal output from the second generation unit 52 and the specified value of the signal obtained by differentiating the cosine wave signal C1 stored in the second storage unit 58. The waveform of C1 is determined. As described above, since the differentiation functions of the generation units 51 and 52 are utilized for the determination of the waveforms of the signals S1 and C1, the sine wave signal S1 is differentiated in order to determine the waveform of the sine wave signal S1. The first selection unit 53 may not have a member for the purpose, and the second selection unit 54 may not have a member for differentiating the cosine wave signal C1 in order to determine the waveform of the cosine wave signal C1. . This reduces the number of parts and simplifies the structure.

  When it is determined by the first determination unit 57 that the first magnetic detection unit 31 is out of order, the information is output to the control unit via the notification unit 70, and the first generation unit 51 and the first selection unit 53, respectively. Is stopped. When the second determination unit 59 determines that the second magnetic detection unit 32 is out of order, the information is output to the control unit via the notification unit 70, and the second generation unit 52 and the second selection unit Each drive of 54 is stopped. When it is determined that each of the magnetic detection units 31 and 32 is out of order, the information is output to the control unit via the notification unit 70, and the driving of the calculation unit 50 is stopped. According to this, when at least one of the magnetic detection units 31 and 32 breaks down, it is possible to suppress wasteful power consumption.

(Second Embodiment)
Next, 2nd Embodiment of this invention is described based on FIGS. FIG. 5 is a block diagram showing a schematic configuration of the rotation angle detection device according to the second embodiment, and corresponds to FIG. 2 shown in the first embodiment. FIG. 6 is a block diagram for explaining a signal when the first magnetic detection unit fails, and corresponds to FIG. 3 shown in the first embodiment. FIG. 7 is a block diagram for explaining a signal when the second magnetic detection unit fails, and corresponds to FIG. 4 shown in the first embodiment. 5-7, the magnet 10 is abbreviate | omitted and in FIG.6 and FIG.7, a failure and abnormality are shown with the broken line.

  Since the rotation angle detection apparatus 100 according to the second embodiment is often in common with that according to the first embodiment, a detailed description of the common parts will be omitted below, and different parts will be described mainly. In addition, the same code | symbol shall be provided to the element same as the element shown in 1st Embodiment.

  In the first embodiment, the example in which the sine wave signals S1 and S2 are input to the first determination unit 57 and the cosine wave signals C1 and C2 are input to the second determination unit 59 has been described. On the other hand, in the present embodiment, the sine wave signal S1 is input to the first determination unit 57, and the cosine wave signal C1 is input to the second determination unit 59.

  The first determination unit 57 determines whether or not the sine wave signal S1 is normal based on the specified value stored in the first storage unit 56, and based on the result, the first magnetic detection unit 31 performs the determination. It is determined whether or not there is a failure. The first determination unit 57 takes out the specified value of the sine wave signal S1 and the specified value of the signal obtained by differentiating the sine wave signal S1 from the first storage unit 56, and uses these specified values as reference values for the sine wave. The amplitude and waveform of the signal S1 are determined.

  Here, when the first determination unit 57 determines that the sine wave signal S1 is normal and the first magnetic detection unit 31 is normal, the sine wave signal S1 is And the information that the first magnetic detection unit 31 is normal is output to the calculation unit 55 and the notification unit 70. Receiving this information, the calculation unit 55 determines that the signals output from the first magnetic detection unit 31 and the first generation unit 51 can be used. In this state, when information indicating that the second magnetic detection unit 32 is out of order is input from the second determination unit 59 to the calculation unit 55, the calculation unit 55 includes the first magnetic detection unit 31 and the first magnetic detection unit 31. The rotation angle is calculated using signals output from the respective generation units 51. When information indicating that the second magnetic detection unit 32 is normal is input from the second determination unit 59 to the calculation unit 55, the calculation unit 55 includes the first magnetic detection unit 31 and the second magnetic detection unit. The rotation angle is calculated using the signals output from the respective 32.

  On the contrary, when the first determination unit 57 determines that the sine wave signal S1 is not normal and the first magnetic detection unit 31 is out of order, there is information that the first magnetic detection unit 31 is out of order. The data is output to the calculation unit 55 and the notification unit 70. Receiving this information, the calculation unit 55 is output from each of the second magnetic detection unit 32 and the second generation unit 52 without using signals output from the first magnetic detection unit 31 and the first generation unit 51, respectively. The rotation angle is calculated using the signal. The first storage unit 56 has the functions of the first memory and the third memory described in the claims.

  The second determination unit 59 determines whether or not the cosine wave signal C1 is normal based on the specified value stored in the second storage unit 58, and based on the result, the second magnetic detection unit 32 performs the determination. It is determined whether or not there is a failure. The second determination unit 59 extracts the specified value of the cosine wave signal C1 and the specified value of the signal obtained by differentiating the cosine wave signal C1 from the second storage unit 58, and uses the specified value as a reference value for the cosine wave. The amplitude and waveform of the signal C1 are determined.

  Here, if the second determination unit 59 determines that the cosine wave signal C1 is normal and the second magnetic detection unit 32 is normal, the cosine wave signal C1 is calculated by the calculation unit 55 and the second generation unit 52. And the information that the second magnetic detection unit 32 is normal is output to the calculation unit 55 and the notification unit 70. Receiving this information, the calculation unit 55 determines that the signals output from the second magnetic detection unit 32 and the second generation unit 52 can be used. In this state, when information indicating that the first magnetic detection unit 31 is out of order is input from the first determination unit 57 to the calculation unit 55, the calculation unit 55 includes the second magnetic detection unit 32 and the second magnetic detection unit 32. The rotation angle is calculated using the signal output from each of the generation units 52. When information indicating that the first magnetic detection unit 31 is normal is input from the first determination unit 57 to the calculation unit 55, the calculation unit 55 includes the first magnetic detection unit 31 and the second magnetic detection unit. The rotation angle is calculated using the signals output from the respective 32.

  On the other hand, when the second determination unit 59 determines that the cosine wave signal C1 is not normal and the second magnetic detection unit 32 is out of order, there is information that the second magnetic detection unit 32 is out of order. The data is output to the calculation unit 55 and the notification unit 70. Receiving this information, the calculation unit 55 is output from each of the first magnetic detection unit 31 and the first generation unit 51 without using signals output from the second magnetic detection unit 32 and the second generation unit 52, respectively. The rotation angle is calculated using the signal. The second storage unit 58 has the functions of the second memory and the fourth memory described in the claims.

  Finally, the calculation unit 55 stops the calculation of the rotation angle when information indicating that each of the first magnetic detection unit 31 and the second magnetic detection unit 32 has failed is input.

  With the above configuration, the rotation angle detection device 100 according to the present embodiment has the same effects as the main effects of the rotation angle detection device 100 according to the first embodiment. That is, for example, as shown in FIG. 6, even when the first magnetic detection unit 31 fails and the signals S1 and C2 become abnormal, the cosine wave signal of the second magnetic detection unit 32 is a normal signal. C1 and the sine wave signal S2 of the second generator 52 can be obtained. On the contrary, as shown in FIG. 7, even when the second magnetic detector 32 fails and the signals C1 and S2 become abnormal, the sine of the first magnetic detector 31 is regarded as a normal signal. The wave signal S1 and the cosine wave signal C2 of the first generator 51 can be obtained. Thus, even if only one of the output signals of the other magnetic detection unit can be obtained because one of the magnetic detection units has failed, two normal signals (a sine wave signal and a cosine signal) that differ in phase by 90 ° are obtained. Wave signal). Therefore, the rotation angle can be detected by calculating these two signals by the calculation unit 55.

  In addition, since the other effect of the rotation angle detection apparatus 100 which concerns on 2nd Embodiment overlaps with the effect of the rotation angle detection apparatus 100 of 1st Embodiment, the description is abbreviate | omitted.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  In the example, each of the magnetic detection units 31 and 32 is a magnetoresistive element that outputs a waveform signal for one cycle when the magnet 10 is rotated by an electrical angle. However, each of the magnetic detection units 31 and 32 may be a magnetoelectric conversion element that converts a magnetic signal into an electric signal, and is not limited to the above example. As the magnetoelectric conversion element, for example, a magnetoresistive element in which variation in resistance due to magnetic flux depends on the shape, or a Hall element that allows current to flow in the thickness direction or the surface direction of the semiconductor substrate may be employed. Furthermore, a solenoid can be adopted. The magnetoresistive element described above is a magnetoresistive element having a fixed layer whose magnetization direction is fixed and a free layer whose magnetization direction changes according to the direction of the magnetic field. Specifically, the magnetoresistive element is a tunnel magnetoresistive element. Or a giant magnetoresistive element.

  In the example, the second generation unit 52 generates the sine wave signal S2 by differentiating the cosine wave signal C1 once and then inverting the sign (positive / negative). However, the method of generating the sine wave signal S2 is not limited to the above example. For example, the second generator 52 may generate the sine wave signal S2 by differentiating the cosine wave signal C1 three times. However, in the case of this configuration, the circuit configuration of the second generation unit 52 is complicated, so that a method of differentiating once and inverting the sign is preferable.

  The control unit that controls the calculation unit 50 and the notification unit 70 are electrically connected, and the failure determination of each of the magnetic detection units 31 and 32 is performed from the determination units 57 and 59 via the notification unit 70 to the control unit. An example of output is shown. However, it is also possible to employ a configuration in which the failure determination of each of the magnetic detection units 31 and 32 is directly output from the determination units 57 and 59 to the control unit without passing through the notification unit 70. Alternatively, a configuration in which the failure determination of each of the magnetic detection units 31 and 32 is output from the determination units 57 and 59 to the control unit via the calculation unit 55 may be employed.

  In the example, the first magnetic detection unit 31 and the second magnetic detection unit 32 are provided apart from each other in the rotation direction of the magnet 10 so that the phase difference of the output signal is different by 90 °. However, it is also possible to employ a configuration in which the first magnetic detection unit 31 and the second magnetic detection unit 32 are provided apart from each other in the rotation direction of the magnet 10 so that the phase difference of the output signals differs by 270 °. Also in this case, the first magnetic detection unit 31 outputs the sine wave signal S1 and the second magnetic detection unit 32 outputs the cosine wave signal C1.

  In the first embodiment, an example is shown in which the first determination unit 57 compares the sine wave signal S2 and the sine wave signal S1, and the second determination unit 59 compares the cosine wave signal C2 and the cosine wave signal C1. It was. However, without performing the above-described comparison, the first determination unit 57 determines whether there is a failure in the first magnetic detection unit 31 based on the specified value in the first storage unit 56 and the sine wave signal S1, and the second A configuration in which the determination unit 59 determines the presence or absence of a failure of the second magnetic detection unit 32 based on the specified value of the second storage unit 58 and the cosine wave signal C1 may be employed. According to this, since the signals S2 and C2 generated by the generation units 51 and 52 are not used, the failure determination of the magnetic detection units 31 and 32 is accelerated, and the signal processing speed is increased.

DESCRIPTION OF SYMBOLS 10 ... Magnet 30 ... Magnetic detection part 31 ... 1st magnetic detection part 32 ... 2nd magnetic detection part 50 ... Calculation part 51 ... 1st production | generation part 52 ... 2nd Generation unit 53 ... first selection unit 54 ... second selection unit 55 ... calculation unit 70 ... notification unit 100 ... rotation angle detection device

Claims (13)

A magnet provided on the rotating body;
A magnetic detection unit for detecting a change in magnetic flux emitted from the magnet due to rotation of the rotating body;
A rotation angle detection device comprising: a calculation unit that calculates a rotation angle of the rotating body based on an output signal of the magnetic detection unit;
The magnetic detection unit includes a first magnetic detection unit and a second magnetic detection unit that are provided apart from each other in the rotation direction of the magnet so that the phase difference of the output signal differs by 90 ° or 270 °,
The calculation unit includes:
A first generator for generating a cosine wave signal based on the sine wave signal output from the first magnetic detector;
A second generator for generating a sine wave signal based on the cosine wave signal output from the second magnetic detector;
A first selection unit that outputs one normal sine wave signal among the sine wave signal of the first magnetic detection unit and the sine wave signal of the second generation unit;
A second selection unit that outputs one normal cosine wave signal among the cosine wave signal of the second magnetic detection unit and the cosine wave signal of the first generation unit;
And a calculation unit that calculates a rotation angle of the rotating body based on a sine wave signal output from the first selection unit and a cosine wave signal output from the second selection unit. Rotation angle detection device. If the first selection unit determines that the first magnetic detection unit is operating normally, the first selection unit outputs a sine wave signal of the first magnetic detection unit, and the first magnetic detection unit fails. If it is determined that the sine wave signal of the second generation unit is output,
When the second selection unit determines that the second magnetic detection unit is operating normally, the second selection unit outputs a cosine wave signal of the second magnetic detection unit, and the second magnetic detection unit fails. 2. The rotation angle detection device according to claim 1, wherein the cosine wave signal of the first generation unit is output when it is determined that the rotation angle is present. The first selection unit determines the presence or absence of a failure of the first magnetic detection unit based on a sine wave signal of the first magnetic detection unit,
The second selection unit determines whether or not the second magnetic detection unit has a failure based on a cosine wave signal of the second magnetic detection unit;
The first selection unit outputs a sine wave signal of the first magnetic detection unit when information indicating that the second magnetic detection unit is out of order is transmitted from the second selection unit,
The second selection unit outputs a cosine wave signal of the second magnetic detection unit when information indicating that the first magnetic detection unit is out of order is transmitted from the first selection unit. The rotation angle detection device according to claim 1 or 2. The first selection unit is configured to store a first memory in which a prescribed value of the sine wave signal of the first magnetic detection unit is stored, and based on the prescribed value and the sine wave signal of the first magnetic detection unit. A first determination unit that determines whether or not one magnetic detection unit is operating normally,
The second selection unit includes a second memory storing a predetermined value of the cosine wave signal of the second magnetic detection unit, and the second selection unit based on the predetermined value and the cosine wave signal of the second magnetic detection unit. The rotation angle detection device according to claim 1, further comprising: a second determination unit that determines whether or not the two magnetic detection units are operating normally. The first selection unit has a third memory storing a prescribed value of a signal obtained by differentiating the sine wave signal of the first magnetic detection unit, and differentiates the prescribed value and the sine wave signal of the first magnetic detection unit. And a third determination unit that determines whether or not the first magnetic detection unit is operating normally based on the signal,
The second selection unit is a fourth memory in which a prescribed value of a signal obtained by differentiating the cosine wave signal of the second magnetic detection unit is stored, and the prescribed value and the cosine wave signal of the second magnetic detection unit are differentiated. The rotation angle according to any one of claims 1 to 4, further comprising: a fourth determination unit that determines whether or not the second magnetic detection unit is operating normally based on the signal. Detection device. The first selection unit compares the sine wave signal of the first magnetic detection unit with the sine wave signal of the second generation unit in order to determine whether the first magnetic detection unit is operating normally . 1 comparison part
The second selection unit compares the cosine wave signal of the second magnetic detection unit with the cosine wave signal of the first generation unit to determine whether the second magnetic detection unit is operating normally . The rotation angle detection device according to claim 1, further comprising a second comparison unit. A magnet provided on the rotating body;
A magnetic detection unit for detecting a change in magnetic flux emitted from the magnet due to rotation of the rotating body;
A rotation angle detection device comprising: a calculation unit that calculates a rotation angle of the rotating body based on an output signal of the magnetic detection unit;
The magnetic detection unit includes a first magnetic detection unit and a second magnetic detection unit that are provided apart from each other in the rotation direction of the magnet so that the phase difference of the output signal differs by 90 ° or 270 °,
The calculation unit includes:
A first determination unit that determines whether or not the sine wave signal output from the first magnetic detection unit is normal;
A second determination unit for determining whether the cosine wave signal output from the second magnetic detection unit is normal;
A first generator for generating a cosine wave signal based on the sine wave signal of the first magnetic detector;
A second generator for generating a sine wave signal based on the cosine wave signal of the second magnetic detector;
Based on the sine wave signal output from the first determination unit or the second generation unit and the cosine wave signal output from the second determination unit or the first generation unit, the rotation angle of the rotating body is determined. A computing unit for computing,
The arithmetic unit, when the first determination unit determines that the sine wave signal of the first magnetic detection unit is abnormal, the sine wave signal of the second generation unit and the cosine wave of the second magnetic detection unit The rotation angle of the rotating body is calculated based on the signal, and the sine wave of the first magnetic detection unit when the second determination unit determines that the cosine wave signal of the second magnetic detection unit is abnormal. A rotation angle detection device that calculates a rotation angle of the rotating body based on a signal and a cosine wave signal of the first generation unit. The arithmetic unit determines that the sine wave signal of the first magnetic detection unit is normal by the first determination unit, and determines that the cosine wave signal of the second magnetic detection unit is normal by the second determination unit. when the rotation angle detection according to claim 7, characterized in that for calculating the rotation angle of the rotating body on the basis of the cosine wave signal of a sine wave signal of the first determination unit and the second determination unit apparatus. The first determination unit determines whether the first magnetic detection unit is based on a sine wave signal of the first magnetic detection unit and a sine wave signal of the first magnetic detection unit stored in the first memory. Determine whether it is working properly,
The second determination unit determines whether the second magnetic detection unit is based on a specified value of a cosine wave signal of the second magnetic detection unit and a cosine wave signal of the second magnetic detection unit stored in a second memory. The rotation angle detection device according to claim 7 or 8, wherein it is determined whether or not the device is operating normally. The first determination unit is based on a specified value of a signal obtained by differentiating the sine wave signal of the first magnetic detection unit stored in the third memory and a signal obtained by differentiating the sine wave signal of the first magnetic detection unit. , Determining whether the first magnetic detection unit is operating normally,
The second determination unit is based on a specified value of a signal obtained by differentiating the cosine wave signal of the second magnetic detection unit stored in the fourth memory and a signal obtained by differentiating the cosine wave signal of the second magnetic detection unit. The rotation angle detection device according to claim 7, wherein it is determined whether or not the second magnetic detection unit is operating normally. The first generator generates a cosine wave signal by differentiating the sine wave signal of the first magnetic detector once.
The said 2nd production | generation part produces | generates a sine wave signal by differentiating the cosine wave signal of the said 2nd magnetic detection part once, and inverting a code | symbol. The rotation angle detection device according to item. The first generator generates a cosine wave signal by differentiating the sine wave signal of the first magnetic detector once.
The rotation angle according to claim 1, wherein the second generation unit generates a sine wave signal by differentiating the cosine wave signal of the second magnetic detection unit three times. Detection device.   The rotation angle detection device according to any one of claims 1 to 12, further comprising a notification unit that notifies the user of the presence or absence of a failure in each of the first magnetic detection unit and the second magnetic detection unit.

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