JP2568902B2 - Rotary body origin position determination device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an origin position (steering neutral position) when a rotating body rotating in conjunction with steering of a steering wheel of a vehicle or the like travels straight.
The present invention relates to an apparatus for determining the origin position of a rotating body which is suitable for use in determining

[Conventional technology]

2. Description of the Related Art Conventionally, in a vehicle such as an automobile, a plurality of slits are formed at equal angular intervals (predetermined angular pitch) in a rotating disk that rotates in association with steering of a steering wheel, and two photo interrupters are adjacent to a passing position of the slits. And perform various controls linked to the steering of the steering wheel.

That is, a pulse-like electric signal (two-phase incremental signal) having the same waveform and a phase shift of about 90 ° is provided to the first and second photointerrupters in conjunction with the steering of the steering wheel.
The incremental signal is counted and the steering direction and the steering angle are detected.

Normally, since the origin position cannot be detected only by the two-phase incremental signal, an origin slit is provided on the rotating disk to detect the origin position, and the origin slit passes through the third photointerrupter. A three-bit configuration is used to obtain the origin signal, and a method is employed in which the relative position of the rotating disk from the origin position is detected by an incremental signal.

However, considering the deviation of the serration between the steering shaft and the steering wheel, the mounting tolerance between the steering shaft and the steering sensor, the poor adjustment of the wheel alignment, and the like, the mounting error is as large as several tens of degrees in the worst case. For this reason, in order to obtain the origin signal, the angle width of the origin slit where the rotating disk is provided is usually enlarged, and even if there is an assembly error of several tens of degrees, as long as the vehicle is traveling straight, A signal can be obtained.

As a result, there arises a problem that the origin position cannot be specified only by the presence or absence of the origin signal, and in order to solve such a problem, as disclosed in JP-A-61-28811. A steering position detecting device has been proposed. That is, the steering position detection device is provided on a steering member that is rotated by a steering operation, detects a steering angle, outputs a steering angle signal, and detects a steering position corresponding to an actual steering angle zero. Neutral zone detecting means for detecting a predetermined steering range (origin range in the present invention) and outputting a steering neutral zone signal, and calculating an average value of the steering angle signal when the steering neutral zone signal is detected. ,
And a neutral position calculating means for outputting the average value as a neutral position signal.By using such a steering position detecting device, regardless of the maintenance condition of the vehicle or the occupant status of the vehicle, the vehicle position can be controlled. The steering neutral position in the straight traveling state can be detected.

[Problems to be Solved by the Invention] However, according to such a steering position detection device, an average value while the steering neutral zone signal is detected is calculated and output as a neutral position signal. There is a problem that it takes time to obtain a new neutral position signal to be updated.

In addition, in order to calculate the average value of the steering angle signal when the steering neutral zone signal is detected, a weighted moving average calculation is performed to calculate the average value. The computation has complicated the circuit configuration.

[Means for solving the problem]

The present invention has been made to solve such a problem, and a slit zone provided at a predetermined angular pitch on an outer peripheral surface thereof and an origin zone provided at an angular width wider than a three-angle pitch of the slit zone. A rotating body that rotates clockwise and counterclockwise in conjunction with an external operation; rotation position detecting means that detects a rotation angle position of the rotating body based on passage of the rotating body through a slit zone; Origin range detecting means for detecting the origin range of the rotating body based on the passage of the origin zone of the body; and, while the origin range is detected by the origin range detecting means, the rotational angle position detected by the rotational position detecting means. The origin zone is divided into a plurality of sub-zones, some of which overlap with each other, based on the divided sub-zones. Was subzone is obtained and a determination means determining the origin position as the origin position.

Further, the apparatus further comprises origin position determining means for judging, from the divided sub-zones, the sub-zone which has continuously contributed to the detection of the origin range while traveling for a predetermined distance or more as the origin position.

[Action]

Therefore, according to the present invention, during the origin zone, the sub zone that has continuously contributed to the detection of the origin range for a predetermined time or more, and the sub-zone that has continuously contributed to the detection of the origin range while traveling for a predetermined distance or more, is the origin position. Determined.

〔Example〕

Hereinafter, an apparatus for determining the origin position of a rotating body according to the present invention will be described in detail.

FIG. 1 is a block diagram showing an embodiment of the origin position determining device. In the figure, reference numeral 5 denotes an input which receives a pulse-like electric signal transmitted from a rotational position detecting sensor (steering angle sensor) 100 (FIG. 2) and transmits a processing signal (an up signal and a down signal) in accordance with steering of the steering wheel. / DOWN
The switching circuit 6 is an UP / DOWN counter that receives a processing signal sent from the UP / DOWN switching circuit 5 as an input.

The steering angle sensor 100 includes a rotating disk (rotating body) 1 that rotates in association with steering of a steering wheel, and photointerrupters 2 to 4 having a light emitting element and a light receiving element. Slits (slit zones) 1a of the same shape are formed at equal angular intervals (predetermined angular pitch P) on the outer peripheral surface. The photo interrupters 2 and 3 are arranged adjacent to each other at a position where the slit 1a passes.
Fig. 3 (a) by the passage of the slit 1a accompanying the rotation of
And (b), a pulse-like electric signal having the same waveform alternately having the "1" level and the "0" level is generated. That is, when the steering wheel is now rotated clockwise (rightward rotation in FIG. 2) from the steering state as shown in FIG. 2, an electric signal in the positive direction centering on the point N is counterclockwise. When rotated, an electric signal is generated in the negative direction about the point N. The electric signal generated in the photo-interrupter 2 has a phase 90 ° ahead of the electric signal generated in the photo-interrupter 3, and the electric signal generated at the origin position (steering neutral position) of the rotating disk 1 which is ideal in design, At the point N shown in the figure, the electric signal generated in the photo interrupter 2 is at the falling or rising timing at which the level changes from "1" level to "0" level or from "0" level to "1" level. The electric signal generated at 3 is "0"
You are in a level state. And this photo interrupter 2
And 3 are input to the UP / DOWN switching circuit 5.

On the other hand, a slit 1b as an origin zone is independently provided at a predetermined rotation angle position on the outer peripheral surface of the rotating disk 1, and the passage of the slit 1b is detected by the photo interrupter 4. That is, the rotational position where the slit 1b faces the photo interrupter 4 is defined as the origin range of the rotating disk 1.
(Origin range detecting means) detects the angular width of the origin range, that is, the angular width α of the slit 1b, to determine the deviation of the serration between the steering shaft and the steering wheel, the mounting tolerance between the steering shaft and the steering sensor, and the poor alignment of the wheel alignment. It is set to be larger than the worst case of the considered assembly error. In the present embodiment, the angle width α of the slit 1b is set to 60 °, and a value of 50 ° is experimentally obtained as a worst case of the assembling error in the investigation of the inventor. Is set to 60 °, a "1" level origin range detection signal (FIG. 3 (c)) can be obtained as an electric signal transmitted by the photointerrupter 4 whenever the vehicle is traveling straight. . Then, the "1" level origin range detection signal is transmitted through its terminal 101 in FIG.
It is provided to one end of an AND gate 8 and one end of OR gates 10 and 11 via an inverter 9.

Here, the photo interrupter 4 is located at the center of the angular width α of the slit 1b at the origin position which is ideal in design of the rotating disk 1, that is, at the point N shown in FIG. In the present embodiment, the slit 1b
Is set slightly wider than 5 times (5 angle pitch) the angle pitch P of the slit 1a.

On the other hand, the UP / DOWN switching circuit 5 processes the input pulsed electric signal and sends out up signals and down signals corresponding to the right steering amount and the left steering amount of the steering wheel from its output terminals 5a and 5b. The UP / DOWN counter 6 counts up or down the count value by the number of input up signals or down signals. That is, the count value of the UP / DOWN counter 6 is basically set to zero with reference to the origin position which is ideal in design of the rotating disk 1, and the count value of the photo-interrupter 2 is increased by right steering of the steering wheel. The output is sequentially increased every falling edge of the output. Further, the count value is sequentially decreased at each rising edge of the output of the photo interrupter 2 by the left steering of the steering wheel. That is, in FIG. 3, if the handle is rotated rightward starting from point N, the count value of the UP / DOWN counter 6 at point a is increased to +1, at point b to +2, and at point c to +2.
3, the count value of the UP / DOWN counter 6 at point d is reduced to −1, at point e to −2, and at point f to −3 when rotated leftward from point N. It goes down sequentially. From the count value of the UP / DOWN counter 6, the rotation angle position (including the rotation direction) of the rotating disk 1, that is, the steering angle (including the steering direction) can be known. In this embodiment, the photo interrupters 2 and 3, the UP / DOWN switching circuit 5 and the UP / DOWN
The counter 6 constitutes a steering angle detecting means (rotational position detecting means).

The count value of the UP / DOWN counter 6 is given to the decoder 7, and the decoder 7 selects an output terminal (not shown) at a position corresponding to the provided count value, and sets its level to " As "0" or "1", it is configured to control an external device that operates in conjunction with steering wheel steering, for example, a cornering lamp system.

On the other hand, the other end of the AND gate 8 has a reference clock generator
A clock signal transmitted from the counter 13 is supplied to the counter 13 by a count-up operation based on the clock signal input through the AND gate 8.
14 "1" level overflow signal (CARRY signal)
Is transmitted, and the "1" level CARRY signal is supplied as a reset signal to the UP / DOWN counter 6 via the OR gate 15. And UP / DOWN
The up signal and the down signal sent from the switching circuit 5 are:
"CP" of T flip-flop 17 via OR gate 16
Also provided as inputs, the "Q" output and "Q bar" output of the T flip-flop 17 are input to one ends of AND gates 18 and 19, and the other ends of the AND gates 18 and 19 are connected via OR gate 20 to two bits. The outputs of the shift registers 21 and 22 are provided. Prompted by a "1" level signal passing through AND gates 18 and 19, one-shot multivibrators (hereinafter simply referred to as "one-shots") 23 and 24 transmit one-shot signals. The one-shot signal transmitted from the inverter 24 and the “1” level signal from the inverter 9 are output to the counter through OR gates 10 and 11.
14 and 13 are given as reset signals.

The shift registers 21 and 22 are composed of D flip-flops 21-1, 21-2 and 22-1, 22-2. The UP signal sent from the UP / DOWN switching circuit 5 is given as the "R" input of the flip-flops 22-1 and 22-2.
2 "CP" input and D flip-flops 21-1, 22-
2, a down signal sent from the UP / DOWN switching circuit 5 is provided.

 Next, the operation of the device configured as described above will be described.

Now, assuming that the automobile is traveling straight, and the rotating disk 1 is located at the original origin position which is ideal in design as shown in FIG. While the "1" level origin range detection signal is being input, the count value of the UP / DOWN counter 6 has a time that continues to be ± 0 much longer than the time that the other values continue. That is, while the "1" level origin range detection signal is being input via the terminal 101, the clock signal sent from the reference clock generator 12 passes through the AND gate 8 and is supplied to the counters 13 and 14. When a predetermined time elapses while the count value of the UP / DOWN counter 6 maintains ± 0, that is, when a predetermined time elapses without sending an up signal or a down signal from the UP / DOWN switching circuit 5,
By the count-up operation based on the supplied clock signal, a "1" level CARRY signal is transmitted from the counters 13 and 14, and the "1" level CARRY signal is supplied to the UP / DOWN counter 6 via the OR gate 15. . As a result, the count value of the U / DOWN counter 6 is reset to ± 0. In this case, the count value of the UP / DOWN counter 6 is already ± 0, and based on such an operation, the count value of the UP / DOWN counter 6 is maintained at ± 0 at the straight steering position.

Here, the CARR of the "1" level is obtained from the counters 13 and 14.
It is assumed that the count in the UP / DOWN counter 6 has shifted from ± 0 to +1 or ± 0 to −1 before the Y signal is transmitted.

That is, if an up signal is sent from the UP / DOWN switching circuit 5 and the count value in the UP / DOWN counter 6 is increased from ± 0 to +1, the up signal sent from the UP / DOWN switching circuit 5 is transmitted through the OR gate 16. To the T flip-flop 17. The T flip-flop 17 receives the up signal through the OR gate 16 and changes its "Q" output and "Q bar" output to "1" and "0".
Level. On the other hand, the UP signal sent from the UP / DOWN switching circuit 5 is supplied to the “CP” inputs of the D flip-flops 21-1 and 21-2 constituting the shift register 21 and the shift register.
"R" of the D flip-flops 22-1 and 22-2 forming the 22
The D flip-flops 21-1 and 22-2 are reset while the "Q" output of the D flip-flop 21-1 is set to the "1" level. That is, even if the "1" level "Q" output sent from the T flip-flop 17 is applied to one end of the AND gate 18, the output of the OR gate 20 to the other end does not become the "1" level state. No one-shot signal is sent from the shot 23, and the counting operation in the counter 14 is not reset. Of course, the counting operation in the counter 13 is also
Since the one-shot signal is not sent from the one-shot 24, it is not reset. In this manner, when a predetermined time has elapsed in the counters 13 and 14, a "1" level CARRY signal is transmitted from the counters 13 and 14 by the count-up operation based on the provided clock signal, and the count in the UP / DOWN counter 6 is counted. The value is returned from +1 to ± 0.

It should be noted that CARRY of "1" level is obtained from the counters 13 and 14.
Before the signal is transmitted, the count value of the UP / DOWN counter 6 shifts from ± 0 to +1 and further from ± 1 to ± 0.
In the case of shifting to, the down signal sent from the UP / DOWN switching circuit 5 is supplied to the T flip-flop 17 via the OR gate 16, and the "Q" output and "Q bar" Output "0" and "1"
Level. On the other hand, the down signal sent from the UP / DOWN switching circuit 5 is transmitted to the “CP” input of the D flip-flops 22-1 and 22-2 constituting the shift register 22 and the shift register.
"R" of D flip-flops 21-1 and 21-2 constituting 21
The D flip-flops 22-1 and 21-2 are reset when the "Q" output of the D flip-flop 22-1 is set to the "1" level. That is, even if the "1" level "Q bar" output sent from the T flip-flop 17 is applied to one end of the AND gate 19, the output of the OR gate 20 to the other end does not become the "1" level state. The one-shot signal is not transmitted from the one-shot 24, and the counting operation in the counter 13 is not reset.

In other words, the total time during which the count value of the UP / DOWN counter 6 maintains ± 0 and +1 is the counter 13
, And are reset to ± 0 when the count value of the UP / DOWN counter 6 is ± 0 or +1.

Above, the count value of the UP / DOWN counter 6 is ±
The operation in the case of going up from 0 to +1 has been described, but the same applies to the case of going down from ± 0 to -1.
The count value of the OWN counter 6 is ± 0 or −
When it becomes 1, it is reset to ± 0.

In this way, the count value of the UP / DOWN counter 6 is set to ± 2 at the straight-ahead steering position using the two-angle pitch width of the slit 1a formed in the rotating disk 1 as a detection zone.
0 will continue to be maintained. That is, by appropriately determining the number of count-ups before the input clock signal overflows to the counters 13 and 14, the UP / D
The count value of the OWN counter 6 is ± 0 and +
In such a short time as continuing two adjacent count values other than 1 or ± 0 and −1, the counter 13 and
The count operation of the clock signal in 14 is reset based on the up signal and the down signal through the UP / DOWN switching circuit 5. For example, when the count value of the UP / DOWN counter 6 increases from ± 0 to +1 and further increases to +2, the UP sent at this time is
The "Q" and "Q bar" outputs of the T flip-flop 17 become "0" and "1" levels by the up signal from the / DOWN switching circuit 5, and the "Q" of the D flip-flop 21-2 in the shift register 21. The output becomes "1" level, a one-shot signal is transmitted from the one-shot 24, and the counting operation of the counter 13 is reset. That is, in the UP / DOWN counter 6,
Since the time during which 1, + 2 continues is much shorter than the time during which ± 0 continues, if the count-up number until the input clock signal overflows in counters 13 and 14 is appropriately determined, then counter 13 And 14 make it impossible to transmit the "1" level CARRY signal.

On the other hand, when the rotating disk 1 is deviated from the origin position which is ideal in design due to the assembling error, the correcting operation which is a feature of the present embodiment is promptly performed as follows. Therefore, the external device can be controlled in conjunction with the steering of the steering wheel without any trouble.

That is, when the rotating disk 1 is at the origin position which is ideal in design, the point Z2 (c) is shifted from the point Z1 (f) shown in FIG.
When the range up to the point is defined as the origin zone in the slit 1b, the origin zone is divided into a region from point d to point b (hereinafter, this region is referred to as a first sub-zone) or from point a to point e. In a region (hereinafter, this region is referred to as a second sub-zone), the time during which the count value of the UP / DOWN counter 6 continues ± 0 and +1 or ± 0 and −1 during straight running is increased. However, when the rotating disk 1 is deviated from the origin position which is ideal in design due to the assembling error, the UP / DOW
The time during which the count value in the N counter 6 continues to a value other than ± 0 becomes longer. For example, if the time during which the count value of the UP / DOWN counter 6 continues to be +2 or -2 becomes longer, the area from the point a to the point c dividing the origin zone (hereinafter, this area is referred to as a third sub-zone) will be described. Alternatively, in the area from the point d to the point f (hereinafter, this area is referred to as a fourth subzone), the time during which the count value of the UP / DOWN counter 6 continues +1 and +2 or -1 and -2 becomes longer. .

If the time during which the count value of the UP / DOWN counter 6 continues +1 and +2 in the third sub-zone becomes longer, the count value of the UP / DOWN counter 6 becomes +1 or +
When the counter value is 2, that is, when the third sub-zone is detected among the four sub-zones partially overlapping with each other, a CARRY signal of "1" level is transmitted from the counter 13 or 14. Becomes UP / DO
The count value in the WN counter 6 is returned to ± 0. That is, the third sub-zone is quickly determined as the origin position, and the count value of the UP / DOWN counter 6 is corrected.

Further, if the time during which the count value of the UP / DOWN counter 6 continues −1 and −2 in the fourth sub-zone becomes longer, when the count value of the UP / DOWN counter 6 is −1 or −2, At the time when the fourth sub-zone is detected from the four sub-zones whose parts partially overlap each other, a CARRY signal of "1" level is sent from the counter 13 or 14, whereby the U
The count value of the P / DOWN counter 6 is returned to ± 0. That is, the fourth sub-zone is quickly determined as the origin position, and the count value of the UP / DOWN counter 6 is corrected.

In this embodiment, the counter 13 and the counter 14 are provided with the clock signal transmitted from the reference clock generator 12 via the AND gate 8, but instead of the clock signal transmitted from the reference clock generator 12, You may comprise so that a pulse signal (distance signal) according to a run distance may be given. That is, when the traveling distance becomes equal to or more than a predetermined value based on the distance signal passing through the AND gate 8, the counters 13 and 14 transmit a "1" level CARRY signal, and UP / DOWN based on the CARRY signal. The count value of the counter 6 may be corrected. In other words, of the four sub-zones whose parts partially overlap each other, the sub-zone that has continuously contributed to the detection of the origin range while traveling for a predetermined distance or more is determined as the origin position, and the count value of the UP / DOWN counter 6 is counted. The correction may be performed. With this configuration, the origin position can be determined more quickly as the traveling speed increases.

Further, in the above-described embodiment, when the origin zone is divided into a plurality of sub-zones, some of which overlap with each other, the width of the sub-zone is twice the minimum resolution of the steering angle sensor. It is needless to say that the minimum resolution is not necessarily twice the minimum resolution of the steering angle sensor, and the width may be twice or more. In the above-described embodiment, the angle width α of the slit 1b is
Although it is set to be slightly wider than the 5 angle pitch of 1a, it is sufficient that the angle width is at least wider than the 3 angle pitch of the slit 1a. In this way, based on the steering angle position detected by the steering angle sensor, In addition, the origin zone can be divided into a plurality of sub-zones, some of which overlap with each other, and it is possible to accurately determine the origin position in the origin zone whose width is enlarged.

Further, in the above-described embodiment, the determination of the steering neutral position in the vehicle has been described as an example. However, the present invention is not limited to the vehicle alone, and the determination of the origin positions of various rotating bodies that rotate in conjunction with an external operation is performed. The present invention is suitable for application to various types of control, and various controls can be performed based on the determined origin position, and its utility value is extremely high. Further, in the embodiment, the device for determining the origin position of the rotating body is configured as a hardware with a specific circuit, but it is needless to say that it can be realized by a software technology using a microcomputer or the like. .

As an example showing the basics of this embodiment, there is Japanese Patent Application No. 63-78529 (rotational body origin position determining device) by the present applicant. In this device, the origin range of each divided sub-zone is determined. A large number of memory areas are required to store the accumulated time that contributed to the detection. On the other hand, in the case of the origin position determining apparatus as in the present embodiment, the memory area can be saved, the circuit configuration can be simplified, and the cost can be reduced as compared with the method of storing the integrated time. It becomes possible.

〔The invention's effect〕

As described above, according to the rotating body origin position determining apparatus according to the present invention, the slit zone provided on the outer peripheral surface at a predetermined angular pitch and the origin provided with an angular width wider than the three-angle pitch of the slit zone are provided. A rotating body having a zone and rotating in a clockwise and counterclockwise direction in conjunction with an external operation; a rotating position detecting means for detecting a rotating angle position of the rotating body based on passage of the rotating body through a slit zone;
Origin range detecting means for detecting an origin range of the rotating body based on passage of the rotating body through the origin zone; and a rotation angle detected by the rotational position detecting means while the origin range is detected by the origin range detecting means. Dividing the origin zone into a plurality of sub-zones that partially overlap each other based on the position, and among the divided sub-zones, a sub-zone that continuously contributes to detection of the origin range for a predetermined time or more and determines the origin position as the origin position Since it is provided with the determination means, it is also provided with the origin position determination means for determining the sub-zone which has contributed to the detection of the origin range continuously while traveling for a predetermined distance or more among the divided sub-zones as the origin position. , The sub-zone has contributed to the detection of the origin range continuously for a predetermined time or more, and the detection of the origin range continues while traveling for a predetermined distance or more. Can be determined as the origin position.For example, when this rotating body is rotated in conjunction with the steering operation of the vehicle, it is possible to accurately and quickly determine the steering neutral position with a simple circuit configuration. Become.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a device for determining the origin of a rotating body according to the present invention, FIG. 2 is a schematic diagram showing a steering angle sensor used in the device, and FIG. FIG. 4 is an output waveform diagram of FIG. 1 ... rotating disk, 1a ... slit, 1b ... slit, 2,
3,4 …… photo interrupter, 5 …… UP / DOWN switching circuit,
6 UP / DOWN counter, 8 AND gate, 12
Reference clock generator, 13,14 …… Counter, 17… T ・
Flip-flops 21, 22,… Shift registers, 23, 24…
…one-shot.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Soichi Tajima 500 Kitawaki, Shimizu City, Shizuoka Prefecture Inside the Koito Manufacturing Shizuoka Plant (72) Inventor Kazuki Takahashi 500 Kitawaki, Shimizu City, Shizuoka Prefecture Koito Manufacturing Shizuoka Co., Ltd. In-plant (72) Inventor Shinzo Yokoyama 500 Kitawaki, Shimizu-shi, Shizuoka Prefecture Koito Manufacturing Co., Ltd.Shizuoka Plant (72) Inventor Akihiro Matsumoto 500, Kitawaki, Shimizu-shi, Shizuoka Prefecture Koito Manufacturing Shizuoka Plant (72) Inventor Takashi Kurita 500 Kitawaki, Shimizu City, Shizuoka Pref. Koito Manufacturing Co., Ltd. Shizuoka Plant (56) References JP-A-61-28811 (JP, A) Real-life Sho 62-158302 (JP, U)

Claims (2)

(57) [Claims] 1. A timepiece having a slit zone provided at a predetermined angular pitch on an outer peripheral surface thereof and an origin zone provided at an angular width wider than a three-angle pitch of the slit zone. A rotating body that rotates in a counterclockwise direction, rotation position detecting means that detects a rotation angle position of the rotating body based on passage of the rotating body through a slit zone, and a rotating body that rotates based on the passage of the rotating body through an origin zone. Origin range detecting means for detecting the origin range, and while the origin range is being detected by the origin range detecting means, the origin zones are partially overlapped with each other based on the rotational angle position detected by the rotational position detecting means. The sub-zone that has contributed to the detection of the origin range for at least a predetermined period of time among the divided sub-zones. Origin position determination device of the rotating body formed by a determination unit. 2. A timepiece having a slit zone provided at a predetermined angular pitch on an outer peripheral surface thereof and an origin zone provided at an angular width wider than a three-angle pitch of the slit zone. A rotating body that rotates in a counterclockwise direction, rotation position detecting means that detects a rotation angle position of the rotating body based on passage of the rotating body through a slit zone, and a rotating body that rotates based on the passage of the rotating body through an origin zone. Origin range detecting means for detecting the origin range, and while the origin range is being detected by the origin range detecting means, the origin zones are partially overlapped with each other based on the rotational angle position detected by the rotational position detecting means. Into sub-zones, and among the divided sub-zones, the sub-zone that continuously contributed to the detection of the origin range while traveling a predetermined distance or more is defined as the origin position. Origin position determination device of the rotating body formed by a constant to the home position determining means.