JPH08260811A - Position detecting apparatus for moving body - Google Patents

Abstract

PURPOSE: To certainly detect the position of a moving body such as a window glass by a method wherein ripple waveform of a driving motor is detected, on the basis of, and the revolution speed of a motor is measured on the decision. CONSTITUTION: The value of parameter corresponding to driving torque of a driving motor 7 is detected by a parameter detecting means comprising a driving electric current detecting means 12. Then, thresholds for detecting ripple waveforms are set one by one, on the basis of the values of detections. In normal operations where the value of driving electric current and driving torque are small, the ripple waveforms are detected, on the basis of the thresholds that are set at small values. In special operations where the driving electric current and the driving torque are large, the ripple waveforms are detected, on the basis of the thresholds that are set at large values. Thereby, noises are not erroneously detected as ripple waveforms, and the ripple waveforms can be detected quickly and correctly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position detecting device for a moving body driven by a drive motor such as a power window, a power seat, a sunroof or an electric tilt handle provided in an automobile.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Laid-Open No. 61-128789.
As disclosed in Japanese Patent Publication, a pulsation (ripple waveform) generated in a current flowing through a drive motor composed of a DC motor is detected, and the pulsation frequency is driven by utilizing the property that the frequency is proportional to the number of rotations and the number of poles of the motor. Measure the number of rotations of the motor,
There is known a position control device for a moving body, which is configured to detect the position of the moving body driven by the drive motor based on the measured value.

[0003]

In the position control device for a moving body constructed as described above, the pulsating component is affected by load fluctuation of the drive motor and characteristic change of the resonance circuit. However, there is a problem that it is difficult to accurately measure the rotation speed of the drive motor.

For example, between the start of a drive motor having a large drive current value and the normal operation of a small drive current value,
Since a large difference occurs in the amplitude of the noise component included in the pulsation component, when the threshold value for pulsation detection is set to a small value so that the pulsation component during steady operation can be detected,
A noise component having a large amplitude generated at the time of start-up will be erroneously detected as a pulsation component. On the other hand, when the threshold value is set to a large value so that only the pulsating component can be detected without detecting the noise component at the time of starting, the detection of the pulsating component in the steady operation is performed. There was a problem that was impossible.

In order to solve the above problems, for example, as disclosed in Japanese Unexamined Patent Publication No. 6-173526, a voltage drop due to a motor current flowing through a drive motor for vertically driving a windshield of an automobile is narrow band bandpass. By inputting to the filter (BPF), the pulsating component contained in the motor current is detected by this BPF, this is converted into a series of pulse trains by the pulse detection circuit, and the number of pulses contained in this pulse train is measured, There is known a position detecting device for a moving body that detects the position of a windshield.
Further, in the moving body detecting device, the center frequency of the pass region of the BPF is switched according to the moving direction of the windshield, and the center frequency is controlled so as to always match the frequency of the pulsating component. There is.

When the pulsating component is detected by the narrow band bandpass filter (BPF) as described above, it is said that the pulsating component can be accurately detected by removing the noise component included in the pulsation. On the other hand, there is an advantage, but since the BPF needs to be provided, the structure is complicated, and when the center frequency of the BPF and the frequency of the pulsating component contained in the motor current are slightly different from the frequency, the beat component is added to the pulse train. Appears, which makes it difficult to convert the pulsating component into an accurate pulse train.

Therefore, in the position detecting device for a moving body described in the above publication, the difference between the frequency of the pulsating component and the center frequency of the BPF is based on the disturbance generated in the pulse train obtained by the pulse train detecting means. Based on the attribute of the beat component detected by the beat detecting means and the beat component detected by the detecting means, the central frequency of the BPF is controlled so as to eliminate the beat component, or the pulsating component is detected. The threshold value is being changed.

However, in the moving body position detecting device having the above-mentioned structure, the beat detecting means detects the changing state of the pulse train for a predetermined time to detect the beat cycle and then removes the BPF. Since complicated control such as controlling the center frequency of the control is required, it is inevitable that a control response delay occurs, and the processing capacity of the control means increases.

The present invention has been made in order to solve the above-mentioned problems, and does not cause a response delay of control,
An object of the present invention is to provide a position detecting device for a moving body, which is capable of accurately measuring the number of rotations of a drive motor composed of a DC motor with a simple configuration and appropriately detecting the position of the moving body based on this.

[0010]

The invention according to claim 1 is
A moving body position detecting device for detecting the position of a moving body driven by a drive motor composed of a DC motor, wherein the ripple waveform detecting means detects a ripple waveform generated when the drive motor operates based on a threshold value. And a rotation speed measuring means for measuring the rotation speed of the drive motor according to the detection signal of the ripple waveform detecting means, and a position estimating means for estimating the position of the moving body according to the measurement value of the rotation speed measuring means. And a parameter detecting means for detecting a value of a parameter corresponding to the drive torque of the drive motor, and a threshold for setting a threshold value corresponding to the drive torque according to the detected value of the parameter. A value setting means is provided.

According to a second aspect of the present invention, there is provided a moving body position detecting device for detecting the position of a moving body driven by a drive motor composed of a DC motor, wherein a plurality of threshold values having different sizes are set. Threshold setting means, ripple waveform detection means for detecting a ripple waveform generated when the drive motor operates based on the plurality of threshold values, and the drive motor of the drive motor according to the detection signal of the ripple waveform detection means. A rotation speed measuring means for measuring the rotation speed and a position estimating means for estimating the position of the moving body according to the measurement value of the rotation speed measuring means are provided, and the ripple waveform detecting means supports a plurality of threshold values. When the ripple waveforms are detected at the same time, the rotation speed of the drive motor is detected by the rotation speed measuring means according to the ripple waveform detection signal corresponding to the large threshold value. It is obtained by configured to measure.

According to a third aspect of the present invention, in the position detecting device for a moving body according to the first or second aspect, a moving body detecting means for detecting that the moving body has reached a preset reference position, and a position An error between the position of the moving body estimated by the estimating means and the position of the moving body detected by the moving body detecting means is detected, and a threshold for ripple waveform detection is learned and updated in a direction to eliminate this error. And a learning means for doing so.

[0013]

According to the first aspect of the present invention, a large threshold value is set by the threshold value setting means when the drive motor having a large driving torque is started, and based on this threshold value. The ripple waveform is detected, and at the time of normal operation of the drive motor having a small drive torque, the threshold value setting means sets a small threshold value, and the ripple waveform is detected based on this threshold value. . Then, the rotation speed of the drive motor is measured according to the detection signal of the ripple waveform, and the position estimation means estimates the position of the moving body driven by the drive motor based on the measured value. Become.

According to the second aspect of the present invention, when the drive motor is operated, the ripple waveforms are respectively detected based on a plurality of threshold values, and only the threshold values set to a small value are detected. When the ripple waveform is detected or when the ripple waveform is detected only based on the threshold value set to a large value, the rotation speed of the drive motor is measured according to the detection signal. Further, when the ripple waveform is detected based on both the small value threshold and the large value threshold, respectively, according to the detection signal of the ripple waveform corresponding to the large value threshold, The rotation speed of the drive motor will be measured.

According to the third aspect of the present invention, the estimated position of the moving body of the position estimating means at the time when the moving body detecting means confirms that the moving body has reached the reference position, and the reference position. If an error is detected, and this error is large, the threshold value for ripple current detection is corrected in the direction of eliminating this error, and this threshold value is set by the threshold value setting means.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a first embodiment in which the moving body detecting apparatus according to the present invention is applied to a power window. The power window includes a window glass 1 and a window regulator 2 that drives the window glass 1 up and down.
It has a control unit 3 for controlling the window regulator 2. The window regulator 2 includes a pair of front and rear guides 4 and 5 for supporting the window glass 1 so as to be vertically movable.
An X-type arm mechanism 6 that supports the lower end of the window glass 1 and a drive motor 7 that is a DC motor that drives the arm mechanism 6 are provided.

When a control signal is output from the control unit 3 to the drive motor 7 in response to a switch operation of the operation switch 8 provided in the vehicle compartment, the drive motor 7 is rotated forward or backward. When the arm mechanism 6 is driven, the window glass 1 in the lower open position is raised and automatically closed, or the window glass 1 in the upper closed position is lowered and automatically opened. ing.

The control section 3 includes a ripple waveform detecting means 9 for detecting a ripple waveform generated when the drive motor 7 is operated, based on a threshold value described later, and a detection signal of the ripple waveform detecting means 9. A rotation speed measuring means 10 for measuring the rotation speed of the drive motor 7, a position estimating means 11 for estimating an ascending / descending position of a moving body made of the window glass 1 according to a measurement value of the rotation speed measuring means 10, A drive current detecting means 12 such as an ammeter for detecting the drive current of the drive motor 7 and a threshold setting means 13 for setting the threshold for detecting the lip waveform are provided.

The ripple waveform detecting means 9 compares the drive current value of the drive motor 7 detected by the drive current detecting means 12 with the threshold value set by the threshold value setting means 13, It is configured to detect a ripple waveform generated when the drive motor 7 operates, depending on the number of rotations and the number of poles. That is, the drive motor 7 detected by the drive current detection means 12
As shown in FIG. 2, for example, a mountain-shaped ripple waveform is generated at a predetermined interval in the driving current, and when the driving current value becomes equal to or more than the threshold value A for detecting the lip waveform, the ripple is generated. The detection signal C having a waveform is used as the rotational speed measuring means 10 described above.
Configured to output to.

The rotation speed measuring means 10 includes a direction determining means 15 for determining the rotation direction of the drive motor 7 according to the output signal of the operation switch 8, and the direction determining means 15 and the lip waveform detecting means 9. A counter 1 that accumulates and stores the number of rotations of the drive motor 7 with the fully open position or the fully closed position of the window glass 1 as an initial position according to the detection signal.
6 and reset means 17 for confirming that the window glass 1 has reached the initial position and resetting the integrated value of the rotational speed stored in the counter 16 to zero.

The counter 16 counts the number of ripple waveform detection signals output from the ripple waveform detecting means 9, and when the direction discriminating means 15 confirms that the drive motor 7 is in the forward rotation state. , Drive motor 7
When the number of detection signals of the ripple waveform corresponding to the number of poles is output, it is determined that the drive motor 7 has made one rotation, and the integrated value of the number of rotations is increased by one. Further, when it is confirmed that the drive motor 7 is in the reverse rotation state, the integrated value of the rotation speed is decremented by 1 when it is determined that the drive motor 7 makes one rotation. .

The reset means 17 sets a timer in accordance with a command signal output from the operation switch 8 to open the window glass 1 in a fully open state, and when the timer expires, the window glass 1 is set to the initial position. It is configured to output a reset signal for judging that the number of revolutions has been reached and resetting the integrated value of the number of revolutions stored in the counter 16. A sensor such as a limit switch for detecting that the window glass 1 is fully opened is provided in the door, and the reset signal is output to the counter 16 when the detection signal is output from the sensor. You may comprise.

The position estimating means 11 is based on the number of revolutions of the drive motor 7 accumulated in the counter 16 of the number of revolutions measuring means 10 and the moving speed of the windshield 1 driven by the drive motor 7. It is configured to estimate the ascending / descending position of 1. That is, since the amount of movement of the window glass 1 per one rotation of the drive motor 7 (moving speed of the window glass 1) is known in advance according to the characteristics of the window regulator 2, the number of rotations stored in the counter 16 is stored. The position estimation means 11 estimates the ascended position of the window glass 1 with respect to the fully open position based on the integrated value of the above and the moving speed.

Further, the threshold value setting means 13 utilizes the fact that there is a proportional relationship between the magnitude of the drive current flowing through the drive motor 7 and the drive torque of the drive motor 7, and thus the drive current detecting means. The threshold value corresponding to the drive torque is set based on the detected value of 12. For example,
The drive torque is calculated by using the drive current value detected by the drive current detection means 12 as a parameter,
By multiplying the detected value of the driving torque by a predetermined coefficient, a threshold value corresponding to the magnitude of the driving torque is linearly set, and this threshold value is output to the ripple waveform detecting means 9. Has been done.

In the above structure, the operation switch 8 is turned on.
When operated, the drive motor 7 is operated according to the operating direction.
Rotates in the normal or reverse direction, and the above window regulator 2
By this, the window glass 1 is driven up and down. Further, the drive current of the drive motor 7 is detected by the drive current detection means 12, and the detection signal is output to the ripple waveform detection means 9 and the threshold value setting means 13, respectively.

The threshold value for ripple waveform detection corresponding to the drive torque is sequentially set by the threshold value setting means 13 in accordance with the detection value of the drive current detecting means 12, and this threshold value is set. Based on the value and the detected value of the drive current, the ripple waveform generated when the drive motor 7 is operated is detected by the ripple waveform detecting means 9, and this detection signal is output to the rotational speed measuring means 10.

That is, during steady operation in which the rotation speed of the drive motor 7 is constant, the drive torque and drive current of the drive motor 7 are small, as shown in FIG. The threshold value A for is also set to a small value. On the other hand, when the drive motor 7 is started or stopped, or during a specific operation in which foreign matter is caught between the window glass 1 and the upper sash, as shown in FIG. Also, since the value of the drive current is large, the threshold value B for ripple waveform detection is set to a large value accordingly.

Then, the threshold values A and B are compared with the detected value of the drive current to detect a ripple waveform, and when the drive current value exceeds the threshold values A and B, the ripple waveform of the ripple waveform is detected. The detection signal C is output from the ripple waveform detecting means 9 to the rotation speed measuring means 10, and this rotation speed measuring means 10 is outputted.
At, the number of pulses of the detection signal C is counted, and the number of rotations of the drive motor 7 is integrated.

In this way, the value of the parameter corresponding to the drive torque of the drive motor 7, that is, the drive current value is detected by the parameter detection means including the drive current detection means 12, and the ripple waveform detection for detecting the ripple waveform is performed according to the detected value. Since the threshold value of is set sequentially, the ripple waveform is detected quickly and reliably based on the threshold value A set to a small value during the steady operation where the driving current value and the driving torque are small. can do.

Further, since the ripple waveform is detected based on the threshold value B set to a large value during the specific operation in which the driving current value and the driving torque are large, a large amplitude included in the ripple waveform is detected. It is possible to reliably prevent the noise N from being erroneously detected as a ripple waveform and to detect the ripple waveform quickly and accurately.

Therefore, the rotational speed of the drive motor 7 can be properly detected by the rotational speed measuring means 10 according to the detection signal C of the ripple waveform, and the moving body made of the window glass 1 is based on the detected value. By estimating the ascending / descending position of the above in the position estimating means 11 quickly and accurately, various controls can be properly executed.

For example, when it is confirmed by the position estimating means 11 that the windshield 1 is located below the fully closed position where foreign matter is likely to be caught, it is determined that the windage detecting means 11 is not shown. Control such as starting the jamming detection operation and reducing the rotation speed of the drive motor 7 by the rotation speed control means can be executed.

In the above embodiment, the timer is set in accordance with the command signal output from the operation switch 8 to bring the window glass 1 into the fully open state, and when the timer expires, the window glass 1 is set to the initial position. Since the reset means 17 for resetting the integrated value of the number of revolutions stored in the counter 16 when it is judged to have arrived is provided, the integrated value of the counter 16 can be reliably initialized at the initial position.

Therefore, it is possible to accurately detect that the window glass 1 is at the fully closed position with a simple structure without providing a new sensor such as a limit switch. Moreover, when there is an error between the vertical position of the window glass 1 estimated by the position estimating means 11 and the actual vertical position, a control for forcibly making this error 0 at the initial position is executed. Therefore, it is possible to reliably prevent the error between the estimated values and the actual ascending / descending position from increasing due to the accumulation of the above errors.

In the above embodiment, the drive current of the drive motor 7 is used as the parameter corresponding to the drive torque of the drive motor 7, and the drive current value is detected by the drive current detecting means 12 including an ammeter. Although the example has been described, the rotation speed of the drive motor 7 or the ascending / descending position of the window glass 1 may be used as the parameter, and the threshold value may be set based on the detected value of the parameter. .

That is, the drive torque of the drive motor 7 and
Since the rotation speed is inversely proportional to the rotation speed, when the rotation speed of the drive motor 7 detected by the rotation speed detection means is low, the ripple waveform detection value having a large value is detected as compared with the case where the rotation speed is high. The threshold value may be set by the threshold value setting means 13.

There is a certain relationship between the ascending / descending position of the window glass 1 and the driving torque of the drive motor 7, as shown in FIG. While reaching the steady operating position b, near the fully closed position c when the window glass 1 approaches the fully closed position
After and, relatively large driving torque acts,
In addition, a relatively small driving torque acts between the steady operating position b and the fully closed position c. Therefore, the set value of the threshold value may be changed stepwise according to the position of the window glass 1 estimated by the position estimating means 11.

Further, as in the second embodiment shown in FIG. 5, the threshold value setting means 13 sets a plurality of threshold values A and B having different magnitudes, and the ripple waveform detecting means 9 drives them. When the ripple waveform generated during the operation of the motor 7 is detected based on the plurality of threshold values A and B, and the ripple waveforms corresponding to the plurality of threshold values A and B are simultaneously detected within a predetermined period, The rotation speed measuring means 10 may be configured to measure the rotation speed of the drive motor 7 in accordance with the detection signal of the ripple waveform corresponding to the large threshold value B.

For example, when two kinds of threshold values A and B of large and small are set and the detection control of the ripple waveform is simultaneously executed based on the threshold values A and B, in the area α where the driving torque is small, Since the ripple waveform is detected based only on the small threshold value A, the detection signal C
The rotation speed is measured based on 1. Further, the amplitude of the noise N is comparatively low.
In the above, since the ripple waveform is detected only on the basis of the large threshold value B, the rotation speed is measured based on the detection signal C2.

On the other hand, in the region γ of large driving torque where the driving torque is large and the noise N of large amplitude is generated, the threshold value A of small value and the threshold value B of large value are both used. Since the ripple waveform is detected as described above, the rotation speed of the drive motor 7 is measured by the rotation speed measuring means 10 according to the detection signal C2 corresponding to the large threshold value B.

With this configuration, the ripple waveform can be accurately detected based on the plurality of preset threshold values A and B while preventing the erroneous detection based on the noise N. At the same time, there is an advantage that the operation for obtaining the threshold values A and B by calculation is unnecessary.

Further, as in the third embodiment shown in FIG. 6, it comprises a timer which operates in response to a fully-closed operation command signal output from the operation switch 8 or a limit switch provided at the upper end of the door opening. , A moving body detecting means 19 for detecting that the moving body such as the windshield 1 has reached a preset reference position such as a fully closed position, the position of the moving body estimated by the position estimating means 11 and the moving body A structure may be provided in which a learning unit 20 that detects an error from the position of the moving body detected by the detection unit 19 and learns and updates the ripple waveform detection threshold value in a direction to eliminate this error.

Then, as shown in FIG. 7, when the position detecting operation of the moving body is started, it is judged whether or not the moving body has reached the reference position (step S1), and when it is judged to be YES. An error δ between the position of the moving body estimated by the position estimating means 11 and the position of the moving body detected by the moving body detecting means 19 is detected (step S2).

Then, it is determined whether or not the absolute value | δ | of the error δ is larger than a preset reference value R (step S3). If NO is determined, the threshold value is Since it is proper, it is judged that the error δ hardly occurs, and the process returns.

If it is determined NO in step S3 and it is confirmed that a large error δ has occurred due to the improper threshold value, the error δ is a positive value. It is determined whether or not (step S4). If YES is determined in this step S4, the rotation speed measuring means 10 causes the drive motor 7 to operate because the threshold value is large.
Is determined to be smaller than the actual number, and it is determined that the error δ has occurred due to this, and in step S5, the learning control for reducing the threshold value is executed, and then the process returns.

That is, in the first embodiment in which the threshold value is set by multiplying the detection value of the drive current detecting means 12 by a coefficient, the value of the coefficient is updated to a small value, Perform learning control. Further, in the second embodiment in which a plurality of thresholds having different magnitudes set by the threshold setting means 13 are used, the learning control for updating the thresholds to large values is executed.

If NO in step S4, the threshold value is small and the noise N is erroneously detected as a ripple waveform, so that the rotation speed measuring means 10 causes the drive motor 7 to operate. Is measured more than the actual speed, and it is determined that the above error δ has occurred, and in step S6, the learning control for increasing the threshold value is executed, and then the process returns.

In the case of such a construction, the individual difference in each vehicle body can be automatically corrected, and
Since it is possible to automatically correct an error caused by deterioration of the regulator 6 or the drive motor 7 with time, it is possible to accurately detect the vertical position of the moving body.

[0049]

As described above, the invention according to claim 1 detects the value of the parameter corresponding to the drive torque of the drive motor by the parameter detection means including the drive current detection means, and responds to the detected value. Since it is configured to sequentially set the threshold for ripple waveform detection described above,
In steady operation where the drive current value and drive torque are small, the ripple waveform can be detected quickly and reliably based on the threshold value set to a small value, while the drive current value and drive torque are large. During operation, by detecting the ripple waveform based on the threshold value set to a large value, noise N having a large amplitude included in the ripple waveform is erroneously detected as a ripple waveform. It is possible to surely prevent the ripple waveform from being detected quickly and accurately.

Therefore, the rotational speed of the drive motor can be properly detected by the rotational speed measuring means according to the detection signal of the ripple waveform with a simple structure without providing a bandpass filter or the like as in the conventional device. The advantage is that the vertical position of the moving body made of windshield can be promptly and accurately estimated by the position estimating means based on the detected value, and a delay in control response can be effectively prevented. .

According to a second aspect of the present invention, the threshold value setting means sets a plurality of threshold values having different magnitudes, and the ripple waveform detection means determines the ripple waveform generated when the drive motor operates. When the ripple waveforms corresponding to the multiple thresholds are detected at the same time by detecting based on multiple thresholds, the number of revolutions is changed according to the detection signal of the ripple waveform corresponding to the large threshold. Since the measuring means is configured to measure the rotation speed of the drive motor, the ripple waveform can be accurately detected based on a plurality of preset threshold values while preventing erroneous detection based on the noise, and There is an advantage that the operation of obtaining the threshold value by calculation is unnecessary.

Further, the invention according to claim 3 is the moving body detecting means for detecting that the moving body has reached a preset reference position, the position of the moving body estimated by the position estimating means, and the moving body. Since the error with respect to the position of the moving body detected by the detecting means is detected, and the learning means for learning and updating the threshold value for ripple waveform detection is provided in the direction of eliminating this error, the regulator or the drive motor with time elapses. An error generated due to deterioration or the like can be automatically corrected to accurately detect the vertical position of the moving body.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a first embodiment of a position detecting device for a moving body according to the present invention.

FIG. 2 is a time chart showing a detected state of a ripple waveform when the driving torque is small.

FIG. 3 is a time chart showing a detected state of a ripple waveform when the driving torque is large.

FIG. 4 is a time chart showing the relationship between drive torque and a threshold value.

FIG. 5 is a time chart showing a ripple waveform detection state in the second embodiment of the present invention.

FIG. 6 is a block diagram showing a third embodiment of the present invention.

FIG. 7 is a flowchart showing a control operation in the third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wind glass (moving body) 7 Drive motor 9 Ripple waveform detecting means 10 Rotation speed measuring means 11 Position estimating means 12 Drive current detecting means (parameter detecting means) 13 Threshold setting means 19 Moving body detecting means 20 Learning means

Claims (3)

[Claims] 1. A position detecting device for a moving body for detecting the position of a moving body driven by a driving motor comprising a DC motor, wherein a ripple waveform generated when the driving motor is operated is detected based on a threshold value. Ripple waveform detection means, and rotation speed measurement means for measuring the rotation speed of the drive motor according to the detection signal of the ripple waveform detection means,
A position estimating means for estimating the position of the moving body according to the measured value of the rotation speed measuring means is provided, and a parameter detecting means for detecting a value of a parameter corresponding to the drive torque of the drive motor, and a parameter detecting means for detecting the value of the parameter. A position detecting device for a moving body, comprising: a threshold value setting means for setting a threshold value having a magnitude corresponding to the drive torque according to a detected value. 2. A moving body position detecting device for detecting the position of a moving body driven by a drive motor comprising a DC motor, comprising: a threshold value setting means for setting a plurality of threshold values having different sizes. A ripple waveform detecting means for detecting a ripple waveform generated during the operation of the drive motor based on the plurality of threshold values, and a rotation for measuring the rotational speed of the drive motor according to a detection signal of the ripple waveform detecting means. A number measuring means and a position estimating means for estimating the position of the moving body according to the measurement value of the rotation speed measuring means are provided,
When the ripple waveform detecting means simultaneously detects ripple waveforms corresponding to a plurality of threshold values, the rotation speed measuring means detects the ripple waveform corresponding to the large threshold value of the drive motor in accordance with the detection signal of the ripple waveform. A position detecting device for a moving body, which is configured to measure the number of rotations. 3. A moving body detecting means for detecting that the moving body has reached a preset reference position, a position of the moving body estimated by the position estimating means, and a moving body detected by the moving body detecting means. 3. The moving body according to claim 1 or 2, further comprising: learning means for detecting an error from the position and learning and updating the threshold value for ripple waveform detection in a direction to eliminate the error. Position detection device.