JP5400583B2 - Rotation angle detection device and rotation angle detection method - Google Patents

Description

  The present invention relates to a rotation angle detection device and a rotation angle detection method.

Conventionally, an apparatus for detecting the rotation angle of a rotating body that can rotate over 360 degrees has been proposed.
For example, Patent Document 1 describes a rotation angle detection device configured as follows. That is, the rotatable rotating body has a gear having n teeth. This gear is engaged with a gear having m teeth and two gears having m + 1 teeth. The angles ψ and θ of these two gears are measured using two periodic angle sensors. This measurement is performed in a contact or non-contact manner. Each of these angle sensors is connected to an electronic evaluation circuit, and this evaluation circuit performs a calculation necessary for detecting the rotation angle φ of the rotating body. In the rotation angle detection device configured as described above, the two angle sensors, which are so-called absolute value sensors, supply the rotation angles ψ and θ of the two gears at the time of switch-on immediately after the rotation angle detection device is switched on. . The angle φ of the rotating body is detected from these angle values, the angle marks or the number of teeth of the gears of the rotating body, and the angle marks or the number of teeth of the two gears.

Japanese Patent No. 3792718

  The rotation angle of each of the two driven gears that mesh with the gear attached to the rotating body that can rotate over 360 degrees is detected by two sensors, and the rotation angle of the rotating body is determined based on the detection results of these two sensors. In the device for calculation, it is conceivable to use a sensor that outputs a pulse width modulation signal having a duty ratio corresponding to the measured rotation angle at a predetermined cycle as the two sensors. When each of the two sensors detects the rotation angle independently and outputs the detection result as a pulse width modulation signal, the rotation angle of the two driven gears used when calculating the rotation angle of the rotating body is calculated. A maximum deviation of the period of the pulse width modulation signal occurs in the detection timing. This deviation does not affect when the rotating body is stopped, but in the rotating state, it causes a detection error of the rotational angle of the rotating body. The faster the rotational angle of the rotating body, the lower the frequency of the pulse width modulation signal, The error tends to increase. Therefore, in order to detect the rotation angle of the rotating body with higher accuracy, it is desirable to calculate the rotation angle of the rotating body in consideration of such points.

For this purpose, the present invention is a rotation angle detection device for detecting the rotation angle of a rotating body, the first driven body and the second driven body rotating in conjunction with the rotation of the rotating body, First detection means for detecting the rotation angle of the first follower at a predetermined period; and second detection means for detecting the rotation angle of the second follower at a predetermined period; Rotation angle calculating means for calculating the rotation angle of the rotating body at a predetermined cycle based on the detection results input by the first detecting means and the second detecting means, the rotating body comprising: The first driven body includes a first driven gear, and the second driven body includes a second driven gear having a number of teeth different from the number of teeth of the first driven gear. And the first driven body and the second driven body include the first driven gear and Serial second driven gear is rotated in conjunction with rotation of the rotary member by a rotational force is applied by the gear, the rotation angle calculation means, each for calculating a rotation angle of the rotating body, wherein A phase difference calculation means for calculating a phase difference between a detection timing of the first detection means and a detection timing of the second detection means; and the first detection means and the second detection means are the first follower. A detection angle calculation means for calculating a detection rotation angle, which is a rotation angle at the time when the rotation angle of the body or the second follower is detected, based on the detection results of the first detection means and the second detection means; Based on the phase difference calculated by the phase difference calculating means, the rotation angle of one of the first driven body and the second driven body calculated by the detection angle calculating means is corrected. Correction means, The rotation angle of the rotating body is calculated based on the rotation angle of the one driven body corrected by the correcting means and the rotation angle of the other driven body calculated by the detection angle calculating means. This is a rotation angle detection device.

Here, the first detection means and the second detection means output a pulse width modulation signal having a duty ratio corresponding to the detected rotation angle at the predetermined period, and the rotation angle calculation means It is preferable that the phase difference calculation means calculates the phase difference based on a pulse width modulation signal input from the first detection means and the second detection means.
The phase difference calculating unit of the rotation angle calculating unit further includes a recognizing unit for recognizing a time when an edge of the pulse width modulation signal output from the first detecting unit and the second detecting unit is input. The time when the edge of the pulse width modulation signal output from the first detection means recognized by the recognition means and the edge of the pulse width modulation signal output from the second detection means are input. It is preferable to calculate the phase difference based on a difference from time.

  The correction means calculates the rotation angle difference between the detected rotation angle at the current calculation time and the detected rotation angle at the previous calculation time calculated by the detected angle calculation means, and the phase difference calculation means calculates It is preferable to correct the rotation angle of the one follower based on the phase difference.

From another point of view, according to the present invention, the first driven body and the second driven body that rotate in conjunction with the rotation of the rotating body, and the rotation angle of the first driven body are predetermined. First detecting means for detecting at a cycle, and second detecting means for detecting a rotation angle of the second follower at a predetermined cycle , wherein the rotating body has a gear, The first driven body has a first driven gear, the second driven body has a second driven gear having a number of teeth different from the number of teeth of the first driven gear, and the first driven gear The driven body and the second driven body have a rotational angle detection in which the first driven gear and the second driven gear rotate in conjunction with the rotation of the rotating body when a rotational force is applied by the gear. A method of detecting a rotation angle of the rotating body in an apparatus, each time a rotation angle of the rotating body is calculated The phase difference between the detection timing of the first detection means and the detection timing of the second detection means is calculated, and the first detection means and the second detection means are the first follower or the second detection means. A detection rotation angle that is a rotation angle at the time when the rotation angle of the second follower is detected is calculated based on the detection results of the first detection means and the second detection means, and based on the calculated phase difference The rotation angle of one of the first driven body and the second driven body is corrected, and the corrected rotation angle of the one driven body and the detected rotation angle of the other driven body are corrected. The rotation angle detection method is characterized in that a rotation angle of the rotating body is calculated based on the rotation angle.

Here, the first detection means and the second detection means output a pulse width modulation signal having a duty ratio corresponding to the detected rotation angle at the predetermined period, and the first detection means It is preferable to calculate the phase difference based on the pulse width modulation signal input from the second detection means.
The difference between the time when the edge of the pulse width modulation signal output from the first detection means is input and the time when the edge of the pulse width modulation signal output from the second detection means is input It is preferable to calculate the phase difference.

  According to the present invention, the rotation angle of the rotating body can be detected with higher accuracy than when the present invention is not employed.

It is a schematic block diagram of the rotation angle detection apparatus which concerns on this Embodiment. It is a figure which shows the relationship between the rotation angle of a rotary body, and the rotation angle of a 1st driven gear and a 2nd driven gear. It is a figure which shows the relationship between the rotation angle of a 1st driven gear and a 2nd driven gear, and the duty ratio of a pulse width modulation signal. It is a figure which shows the relationship between the rotation angle of a 1st driven gear and a 2nd driven gear, and the pulse width modulation signal which a 1st rotation angle sensor and a 2nd rotation angle sensor output. It is a figure which shows a mode that the timing which outputs the detection of a 1st rotation angle sensor and a 2nd rotation angle sensor, and a detection result shifts | deviates. It is a flowchart which shows the procedure of the rotation angle calculation process of the rotary body which ECU performs.

Hereinafter, this embodiment will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic configuration diagram of a rotation angle detection device 1 according to the present embodiment.
The rotation angle detection device 1 is a device that detects the rotation angle of a rotating body 100 that is rotatably supported by a body frame of a vehicle such as an automobile.
The rotating body 100 is a rotating shaft to which, for example, a steering wheel is connected, and is rotatably supported by the housing via a bearing such as a ball bearing fixed to a housing (not shown) that is a member fixed to the main body frame. ing.

  By detecting the rotation angle of the rotating body 100 by the rotation angle detecting device 1, it is possible to detect the rotation angle of the steering wheel connected to the rotating body 100, and thus to grasp the traveling direction of the vehicle on which the steering wheel is mounted. It becomes possible. The detection result of the rotation angle detection device 1 is used in various control devices such as a device that performs route guidance and a device that changes the hardness of the suspension according to the steering angle.

Below, the rotation angle detection apparatus 1 is explained in full detail.
The rotation angle detection device 1 includes a gear 101 that is an example of a gear attached to the rotating body 100, a first driven gear 111 that is an example of a first driven gear that meshes with the gear 101, and a second that meshes with the gear 101. And a second driven gear 121 as an example of the driven gear. For example, the first driven gear 111 is rotatable with respect to the housing by being attached to the first rotation shaft 110 that is rotatably supported by the housing. The second driven gear 121 is also rotatable with respect to the housing, for example, by being attached to the second rotating shaft 120 that is rotatably supported by the housing. The first driven gear 111 and the first rotating shaft 110 constitute an example of a first driven body, and the second driven gear 121 and the second rotating shaft 120 constitute an example of a second driven body. Configure.

FIG. 2 is a diagram illustrating the relationship between the rotation angle of the rotating body 100 and the rotation angles of the first driven gear 111 and the second driven gear 121.
The number of teeth of the gear 101 is n, the number of teeth of the first driven gear 111 is m, and the number of teeth of the second driven gear 121 is (m + 1). Then, the relationship between the number of teeth of the gear 101 and the number of teeth of the first driven gear 111 and the relationship between the number of teeth of the gear 101 and the number of teeth of the second driven gear 121 are taken into account, and the first driven gear 111 is taken into consideration. 2 and the number of teeth of the second driven gear 121 is (m + 1), the rotation angle of the rotating body 100 and the first driven gear 111, as shown in FIG. The figure which shows the relationship with the rotation angle of the 2nd driven gear 121 can be obtained. It can be exemplified that n is 81 and m is 21.

Further, the rotation angle detection device 1 includes a first rotation angle sensor 112 as an example of first detection means for detecting the rotation angle of the first driven gear 111. The first rotation angle sensor 112 is arranged outside the first driven gear 111 in the radial direction of rotation, and a plurality of first rotation angle sensors 112 are formed in the teeth of the first driven gear 111 or in the circumferential direction of the first rotary shaft 110. Based on the angle mark, the rotation angle of the first driven gear 111 is detected.
Similarly, the rotation angle detection device 1 has a second rotation angle sensor 122 as an example of second detection means for detecting the rotation angle of the second driven gear 121. The second rotation angle sensor 122 is disposed outside the second driven gear 121 in the rotation radial direction, and a plurality of second rotation angle sensors 122 are formed in the circumferential direction of the second driven gear 121 or the second rotation shaft 120. Based on the angle mark, the rotation angle of the second driven gear 121 is detected.
Then, the rotation angle detection device 1 is based on the output values from the first rotation angle sensor 112 and the second rotation angle sensor 122, in other words, by the first rotation angle sensor 112 and the second rotation angle sensor 122. An electronic control unit (hereinafter simply referred to as “ECU”) 150 (see FIG. 1) as an example of a rotation angle calculation means for calculating the rotation angle of the rotating body 100 based on the input detection result is provided. .

The first rotation angle sensor 112 and the second rotation angle sensor 122 respectively generate a pulse width modulation signal PWM having a duty ratio corresponding to the detected rotation angle of the first driven gear 111 or the second driven gear 121. Output at a predetermined cycle.
FIG. 3 is a diagram showing the relationship between the rotation angles of the first driven gear 111 and the second driven gear 121 and the duty ratio of the pulse width modulation signal PWM.
As shown in FIG. 3, the first rotation angle sensor 112 and the second rotation angle sensor 122 respectively set the rotation angles 0 to 360 degrees of the first driven gear 111 or the second driven gear 121 as duty cycles. It is converted into a pulse width modulation signal PWM having a ratio of 5% to 95% and output.

FIG. 4 shows the relationship between the rotation angle of the first driven gear 111 and the second driven gear 121 and the pulse width modulation signal PWM output from the first rotation angle sensor 112 and the second rotation angle sensor 122. FIG.
As shown in FIG. 4, the first rotation angle sensor 112 generates a pulse width modulation signal PWMA having a PWM signal ON (High) time PWMA_ON corresponding to the rotation angle of the first driven gear 111 at a predetermined cycle. The second rotation angle sensor 122 outputs a pulse width modulation signal PWMB having a PWM signal ON (High) time PWMB_ON corresponding to the rotation angle of the second driven gear 121, with a predetermined period PWMB_T. To output.

  The ECU 150 is an arithmetic logic circuit including a CPU, a ROM, a RAM, a backup RAM, and the like. The ECU 150 is connected to the first rotation angle sensor 112 and the second rotation angle sensor 122, and power is supplied to the first rotation angle sensor 112 and the second rotation angle sensor 122 via the ECU 150. . ECU 150 also receives pulse width modulation signals PWMA and PWMB output from first rotation angle sensor 112 and second rotation angle sensor 122, and the period of pulse width modulation signals PWMA and PWMB and the pulse width modulation signal. The phase difference between the PWMA and the pulse width modulation signal PWMB and the time of the ON (High) pulse of the pulse width modulation signals PWMA and PWMB are recognized.

More specifically, ECU 150 includes a timer counter for measuring the period of pulse width modulation signals PWMA and PWMB, the phase difference between pulse width modulation signal PWMA and pulse width modulation signal PWMB, and pulse width modulation signal PWMA. And a total of three timer counters including two timer counters for measuring the time of ON (High) pulse of each PWMB.
The timer counter for measuring the periods and phase differences of the pulse width modulation signals PWMA and PWMB is set to a free-run counter, and captures the value of the counter at the falling edge of the pulse width modulation signals PWMA and PWMB into the capture register. Also, using the buffer function, the current (n-th) counter values TA (n) and TB (n) of the pulse width modulation signals PWMA and PWMB, and the previous (n-1th) counter value TA (n−1) ) And TB (n-1) can be stored.
Each timer counter for measuring the time of the ON (High) pulse of each of the pulse width modulation signals PWMA and PWMB starts at the rising edge of the pulse width modulation signal PWMA or PWMB, stops at the falling edge, Captures the value into the capture register and clears the counter.

  Then, ECU 150 reads the latest pulse width modulation signals PWMA and PWMB ON pulse times taken into the capture register at a predetermined period T (see FIG. 4), and based on this time, rotator 100 An arithmetic processing for calculating the rotation angle φ of the. FIG. 4 shows a process for calculating the rotation angle φ of the rotating body 100 performed by the ECU 150 and the period (PWMA_T and PWMB_T) and timing at which the first rotation angle sensor 112 and the second rotation angle sensor 122 detect the rotation angle. The timing and cycle are shown.

  Here, the first rotation angle sensor 112 and the second rotation angle sensor 122 detect the rotation angle of the first driven gear 111 or the second driven gear 121 independently, that is, asynchronously, and detect the rotation angle. The result is output as a pulse width modulation signal PWMA or PWMB. Therefore, even if the first rotation angle sensor 112 and the second rotation angle sensor 122 are intended to output the detection and the detection result at the same predetermined cycle, the individual difference between these two sensors. The periods of both sensors may be different. In such a case, even when the ECU 150 is started, that is, when the first rotation angle sensor 112 and the second rotation angle sensor 122 are started, even if the detection timing of these sensors and the output timing of the detection result are the same, both sensors There is a possibility that the timing of detection and the output of the detection result may be shifted due to the difference in period. FIG. 5 is a diagram illustrating a state in which the detection of the first rotation angle sensor 112 and the second rotation angle sensor 122 and the timing of outputting the detection result are shifted. FIG. 4 shows a case where a phase difference (deviation) ΔTAB occurs at the n-th detection timing by the first rotation angle sensor 112 and the second rotation angle sensor 122.

  Then, the first rotation angle sensor 112 and the second rotation angle sensor 122 detect the rotation angle of the first driven gear 111 or the second driven gear 121, and the detection result is represented by the pulse width modulation signal PWMA or When the phase difference (TAB) ΔTAB shown in FIG. 4 occurs at the timing of output as PWMB, the latest pulse width modulation signals PWMA and PWMB are used when performing arithmetic processing for calculating the rotation angle φ of the rotating body 100. Even if the time of the ON pulse is read and the calculation process is performed, the timing detected by the first rotation angle sensor 112 and the second rotation angle sensor 122 is different, so that there is an error in the rotation angle φ of the rotating body 100. May occur. In particular, when the rotator 100 is rotating, it becomes a cause of detection error, and this error tends to increase as the rotation angle of the rotator 100 increases and the frequency of the pulse width modulation signals PWMA and PWMB decreases. . Therefore, ECU 150 according to the present embodiment calculates the rotation angle of rotating body 100 as follows in consideration of this point.

Hereinafter, the rotation angle calculation process of the rotating body 100 performed by the ECU 150 will be described using a flowchart.
FIG. 6 is a flowchart showing the procedure of the rotation angle calculation process of the rotating body 100 performed by the ECU 150. The ECU 150 performs this rotation angle calculation process in the cycle T described above.
First, ECU 150 calculates detection periods PWMA_T and PWMB_T of first rotation angle sensor 112 and second rotation angle sensor 122 (step 601).
The process of calculating the detection period PWMA_T of the first rotation angle sensor 112 is based on the counter value TA (n) at the falling edge of the pulse width modulation signal PWMA in the current (nth) flow stored in the RAM. This is a process of subtracting the counter value TA (n−1) at the falling edge of the pulse width modulation signal PWMA in the previous (n−1) th flow (PWMA_T = TA (n) −TA (n−1). ).
In addition, the process of calculating the detection cycle PWMB_T of the second rotation angle sensor 122 starts from the counter value TB (n) at the falling edge of the pulse width modulation signal PWMB in the current flow (n-th) flow (n− This is a process of subtracting the counter value TB (n−1) at the falling edge of the pulse width modulation signal PWMB in the first flow (PWMB_T = TB (n) −TB (n−1)).

Thereafter, the ECU 150 calculates the rotation angle θA of the first driven gear 111 and the rotation angle θB of the second driven gear 121 (step 602).
The process of calculating the rotation angle θA of the first driven gear 111 reads the latest PWM signal ON time PWMA_ON corresponding to the rotation angle of the first driven gear 111 captured in the capture register, and the following equation (1) And the calculation is performed by substituting the detection cycle PWMA_T calculated in step 601 into the following equation (1).
θA = (PWMA_ON−PWMA_T × 0.05) / (PWMA_T × 0.9) × K1 (1)
Here, K1 is a coefficient for converting the pulse width modulation signal PWMA to the rotation angle θA, and is a coefficient depending on the width of the duty ratio used for the pulse width modulation signal PWMA and the maximum rotation angle of 360 degrees. It is remembered.
Further, the process of calculating the rotation angle θB of the second driven gear 121 reads the latest PWM signal ON time PWMB_ON corresponding to the rotation angle of the second driven gear 121 captured in the capture register, and the following equation ( This is a process of assigning to 2) and calculating by substituting the detection cycle PWMB_T calculated in step 601 into the following equation (2).
θB = (PWMB_ON−PWMB_T × 0.05) / (PWMB_T × 0.9) × K2 (2)
Here, K2 is a coefficient for converting the pulse width modulation signal PWMB into the rotation angle θB, and is a coefficient depending on the width of the duty ratio used for the pulse width modulation signal PWMB and the maximum rotation angle of 360 degrees. It is remembered.
In the present embodiment, the relationship between the width of the duty ratio used for pulse width modulation signal PWMB and the maximum rotation angle 360 degrees is the relationship between the width of the duty ratio used for pulse width modulation signal PWMA and the maximum rotation angle 360 degrees. Since the relationship is the same, it is preferable that K2 = K1.

  Next, the ECU 150 calculates a phase difference (displacement) ΔTAB of the n-th detection timing by the first rotation angle sensor 112 and the second rotation angle sensor 122 (step 603). Here, the n-th detection timing by the first rotation angle sensor 112 and the second rotation angle sensor 122 is that a falling edge is input immediately before the timing of the n-th rotation angle calculation process by the ECU 150. This is the detection timing that is the basis of the pulse width modulation signals PWMA and PWMB. The processing in step 603 is processing for calculating the absolute value of the value obtained by subtracting the counter value TB (n) from the counter value TA (n) (ΔTAB = | TA (n) −TB (n) |). .

Thereafter, ECU 150 determines whether or not counter value TA (n) is larger than counter value TB (n) (TA (n)> TB (n)) (step 604).
If the determination in step 604 is affirmative, the n-th detection timing by the second rotation angle sensor 122 is ahead of the n-th detection timing by the first rotation angle sensor 112. The following processing is performed to calculate the rotation angle φ of the rotating body 100 in consideration of the rotation angle of the second driven gear 121 between ΔTAB.

That is, first, the angular velocity ωB of the second driven gear 121 is calculated (step 605). This is based on the second angle calculated in step 602 in the previous (n-1) th flow from the rotation angle θB (n) of the second driven gear 121 calculated in step 602 in the current (nth) flow. This is a process of multiplying a value obtained by subtracting the rotational angle θB (n−1) of the driven gear 121 by a predetermined coefficient KB for converting the rotational angle difference of the second driven gear 121 into an angular velocity (ωB = ( θB (n) −θB (n−1)) × KB). The coefficient KB is preferably a value (1 / T) obtained by dividing 1 by the period T of the rotation angle calculation process. The coefficient KB is stored in advance in the ROM.
Next, correction amounts αA and αB for correcting the rotation angle θA of the first driven gear 111 and the rotation angle θB of the second driven gear 121 calculated in step 602 are calculated (step 606). This is calculated by multiplying the correction amount αB of the second driven gear 121 that should take into consideration the rotation angle between the phase differences ΔTAB by multiplying the angular velocity ωB calculated in step 605 by the phase difference ΔTAB (αB = ωB × ΔTAB). ), A process of setting the correction amount αA of the first driven gear 111 to zero (αA = 0).

On the other hand, when a negative determination is made in step 604, the n-th detection timing by the first rotation angle sensor 112 is ahead of the n-th detection timing by the second rotation angle sensor 122. The following processing is performed to calculate the rotation angle φ of the rotating body 100 in consideration of the rotation angle of the first driven gear 111 between ΔTAB.
That is, first, the angular velocity ωA of the first driven gear 111 is calculated (step 607). This is the first calculated in step 602 in the previous (n-1) th flow from the rotation angle θA (n) of the first driven gear 111 calculated in step 602 in the current (nth) flow. This is a process of multiplying a value obtained by subtracting the rotation angle θA (n−1) of the driven gear 111 by a predetermined coefficient KA for converting the rotation angle difference of the first driven gear 111 into an angular velocity (ωA = ( θA (n) −θA (n−1)) × KA). The coefficient KA is preferably a value (1 / T) obtained by dividing 1 by the period T of the rotation angle calculation process. The coefficient KA is stored in advance in the ROM.
Next, correction amounts αA and αB for correcting the rotation angle θA of the first driven gear 111 and the rotation angle θB of the second driven gear 121 calculated in step 602 are calculated (step 608). This is calculated by multiplying the correction amount αA of the first driven gear 111 that should consider the rotation angle between the phase differences ΔTAB by multiplying the angular velocity ωA calculated in step 607 by the phase difference ΔTAB (αA = ωA × ΔTAB). ), A process of setting the correction amount αB of the second driven gear 121 to zero (αB = 0).

  Thereafter, ECU 150 calculates rotation angle θA ′ of first driven gear 111 and rotation angle θB ′ of second driven gear 121 in consideration of correction amounts αA and αB (step 609). This is a process of adding the correction amounts αA and αB calculated in step 606 or step 608 to the rotation angle θA of the first driven gear 111 and the rotation angle θB of the second driven gear 121 calculated in step 602. (ΘA ′ = θA + αA, θB ′ = θB + αB).

  Thereafter, the ECU 150 calculates an angle difference ΔθAB between the rotation angle θA ′ of the first driven gear 111 and the rotation angle θB ′ of the second driven gear 121 corrected in step 609 (ΔθAB = θA′−θB ′). (Step 610). Then, ECU 150 determines whether or not angle difference ΔθAB calculated in step 610 is smaller than 0 degrees (deg) (step 611). If an affirmative determination is made in step 611, the value obtained by adding 360 degrees to the angle difference ΔθAB calculated in step 610 is replaced with ΔθAB (ΔθAB = ΔθAB + 360) (step 612), and the process proceeds to step 613. On the other hand, if a negative determination is made in step 611, the process proceeds to step 613.

Then, ECU 150 calculates rotation angle φ of rotating body 100 in step 613. This is a process of calculating by the following equation (3).
φ = ΔθAB × K3 (3)
Here, K3 is a coefficient for converting the angle difference ΔθAB between the rotation angle θA ′ of the first driven gear 111 and the rotation angle θB ′ of the second driven gear 121 into the rotation angle φ of the rotating body 100. The number of teeth of 101, the number of teeth of the first driven gear 111, the number of teeth of the second driven gear 121, and the detection angles of the first rotation angle sensor 112 and the second rotation angle sensor 122 are 360 degrees. It is a coefficient and is a coefficient stored in the ROM in advance.

  As described above, in the rotation angle detection device 1 according to the present embodiment, the first rotation angle sensor 112, the second rotation angle sensor 122, and the like each time processing for calculating the rotation angle φ of the rotating body 100 is performed. The rotation angle of the first driven gear 111 or the second driven gear 121 is detected, the phase difference ΔTAB of the timing at which the detection result is output as the pulse width modulation signal PWMA or PWMB is calculated, and the calculated phase difference ΔTAB is calculated. Since the rotation angle φ of the rotating body 100 is calculated in consideration of the rotation angle of the first driven gear 111 or the second driven gear 121, the rotation angle φ of the rotating body 100 can be detected with high accuracy. .

  Regarding the rotation angle calculation processing of the rotating body 100 performed by the ECU 150 described above, the cycles PWMA_T and PWMB_T of the first rotation angle sensor 112 and the second rotation angle sensor 122 are calculated for each calculation processing (step 601). Based on the calculated cycles PWMA_T and PWMB_T, the rotation angle θA of the first driven gear 111 and the rotation angle θB of the second driven gear 121 are calculated (step 602), which are predetermined as the cycles PWMA_T and PWMB_T. May be used. That is, when calculating the rotation angle of the rotating body 100, the ECU 150 starts from the process of step 602 without performing the process of step 601 in the flowchart shown in FIG. In step 602, ECU 150 reads PWMA_T and PWMB_T stored in the ROM, and calculates rotation angle θA of first driven gear 111 and rotation angle θB of second driven gear 121. . Even in such a case, each time the process of calculating the rotation angle φ of the rotating body 100 is performed, the phase difference between the detection timings of the first rotation angle sensor 112 and the second rotation angle sensor 122 and the output of the detection result is detected. Since ΔTAB is calculated and the rotation angle φ of the rotating body 100 is calculated in consideration of the rotation angle of the first driven gear 111 or the second driven gear 121 corresponding to the calculated phase difference ΔTAB, the rotation of the rotating body 100 is accurately performed. It becomes possible to detect the angle φ.

DESCRIPTION OF SYMBOLS 1 ... Rotation angle detection apparatus, 100 ... Rotating body, 101 ... Gear, 110 ... 1st rotating shaft, 111 ... 1st driven gear, 112 ... 1st rotating angle sensor, 120 ... 2nd rotating shaft, 121 ... Second driven gear, 122 ... Second rotation angle sensor, 150 ... ECU

Claims (7)

A rotation angle detection device for detecting a rotation angle of a rotating body,
A first driven body and a second driven body that rotate in conjunction with the rotation of the rotating body;
First detection means for detecting a rotation angle of the first follower at a predetermined cycle;
Second detection means for detecting a rotation angle of the second follower at a predetermined cycle;
A rotation angle calculation means for calculating a rotation angle of the rotating body at a predetermined cycle based on the detection results input by the first detection means and the second detection means;
With
The rotating body has a gear;
The first driven body has a first driven gear;
The second driven body has a second driven gear having a number of teeth different from the number of teeth of the first driven gear;
The first driven body and the second driven body rotate in conjunction with the rotation of the rotating body by applying a rotational force to the first driven gear and the second driven gear by the gear. And
The rotation angle calculation means includes
Phase difference calculating means for calculating a phase difference between the detection timing of the first detection means and the detection timing of the second detection means each time the rotation angle of the rotating body is calculated;
A detected rotation angle that is a rotation angle at the time when the first detection means and the second detection means detect the rotation angle of the first follower or the second follower, and the first detection means and the second detection means. Detection angle calculation means for calculating based on the detection result of the second detection means;
Correction for correcting the rotation angle of one of the first driven body and the second driven body calculated by the detection angle calculating means based on the phase difference calculated by the phase difference calculating means. Means,
Have
The rotation angle of the rotation body is calculated based on the rotation angle of the one follower corrected by the correction means and the rotation angle of the other follower calculated by the detection angle calculation means. Detection device. The first detection means and the second detection means output a pulse width modulation signal having a duty ratio corresponding to the detected rotation angle at the predetermined period,
The phase difference calculation means of the rotation angle calculation means calculates the phase difference based on a pulse width modulation signal input from the first detection means and the second detection means. The rotation angle detection device according to 1. Recognizing means for recognizing the time when the edge of the pulse width modulation signal output from the first detecting means and the second detecting means is input;
The phase difference calculation means of the rotation angle calculation means is output from the time when the edge of the pulse width modulation signal output from the first detection means recognized by the recognition means is input and from the second detection means. The rotation angle detection device according to claim 2, wherein the phase difference is calculated based on a difference from a time when an edge of the pulse width modulation signal is input.   The correction means calculates the rotation angle difference between the detected rotation angle at the current calculation time and the detected rotation angle at the previous calculation time calculated by the detection angle calculation means, and the position calculated by the phase difference calculation means. The rotation angle detection device according to any one of claims 1 to 3, wherein a rotation angle of the one follower is corrected based on a phase difference. A first driven body and a second driven body that rotate in conjunction with the rotation of the rotating body;
First detection means for detecting a rotation angle of the first follower at a predetermined cycle;
Second detection means for detecting a rotation angle of the second follower at a predetermined cycle;
Equipped with a,
The rotating body has a gear;
The first driven body has a first driven gear;
The second driven body has a second driven gear having a number of teeth different from the number of teeth of the first driven gear;
The first driven body and the second driven body rotate in conjunction with the rotation of the rotating body by applying a rotational force to the first driven gear and the second driven gear by the gear. A rotation angle detection method for the rotating body in a rotation angle detection device that comprises:
Every time the rotation angle of the rotating body is calculated, the phase difference between the detection timing of the first detection means and the detection timing of the second detection means is calculated,
A detected rotation angle that is a rotation angle at the time when the first detection means and the second detection means detect the rotation angle of the first follower or the second follower, and the first detection means and the second detection means. Calculation based on the detection result of the second detection means,
Based on the calculated phase difference, the rotation angle of one of the first driven body and the second driven body is corrected,
A rotation angle detection method comprising: calculating a rotation angle of the rotating body based on the corrected rotation angle of the one driven body and the detected rotation angle of the other driven body. The first detection means and the second detection means output a pulse width modulation signal having a duty ratio corresponding to the detected rotation angle at the predetermined period,
6. The rotation angle detection method according to claim 5 , wherein the phase difference is calculated based on a pulse width modulation signal input from the first detection unit and the second detection unit. The phase difference is determined by the difference between the time when the edge of the pulse width modulation signal output from the first detection means is input and the time when the edge of the pulse width modulation signal output from the second detection means is input. The rotation angle detection method according to claim 6 , wherein:

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