JP2008020443A - Adjusting technique for signal amplification factor of rotation detecting sensor and rotation detecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adjusting technique for signal amplification factor of rotation detecting sensor and a rotation detecting device capable of detecting the signal of only rotation of rotational bodies and implementing no pulse output during the time of vibration. <P>SOLUTION: The adjusting technique for signal amplification factor of a rotation detecting sensor, which is equipped with a detecting element 1 detecting the signal induced by displacement of a rotational body 7, an amplifier 3 amplifying the signal concerned, and an automatic gain controlling circuit 5 adjusting the amplification factor at the amplifier 3 automatically, includes a rotation judging step judging rotating of the rotational body 7, an amplification factor adjusting step adjusting the amplification factor of the signal in the amplifier 3, and an amplification factor limiting step limiting the aforementioned amplification factor at the starting time of the aforementioned rotation detecting sensor to the range of a predetermined amplification factor containing the amplification factor adjusted by the aforementioned amplification factor adjusting step, when the rotational body 7 is judged to be rotating at the aforementioned rotation judging step. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a method for adjusting a signal amplification factor of a rotation detection sensor and a rotation detection device that detect a signal caused by the displacement of a rotating body and amplify the signal to obtain an output signal corresponding to the rotation state of the rotating body.

  The rotation detection sensor detects, for example, a change in magnetic flux generated with the rotation of the rotating body. As shown in FIG. 1, the rotating body 7 includes many teeth 8 formed of a ferromagnetic material on the outer peripheral portion. The detection element 1 such as a Hall element or a magnetoresistive element is arranged in a magnetic circuit made up of the teeth 8 of the rotating body 7 and a magnet. When the ferromagnetic tooth 8 is moved by the rotation of the rotating body 7, the magnetic flux penetrating the detection element 1 changes. The detection element 1 converts a change in magnetic flux penetrating into an electrical signal. The electrical signal output from the detection element 1 is used to detect the rotational speed and direction of the rotating body 7.

  The signal of the detection element 1 is amplified by an amplifier, binarized by, for example, a waveform shaping circuit, and converted into a pulse corresponding to the rotational speed of the rotating body. The rotation detection device usually includes a magnetic detection element 1, an amplification circuit, and one integrated circuit that generates pulses (there may be no integration).

  The above-mentioned type of rotation detection sensor that is currently commercialized increases the degree of freedom in selecting the separation distance between the teeth 8 of the rotation body 7 and the detection element 1 in order to extend the separation distance from the detectable rotation body. In addition, the following configuration is adopted by increasing the variable range of the signal amplification factor. For example, a predetermined number of amplitude fluctuations (specifically, the rotator is turned on) from power-on (start of energization) so that a binarization process is executed with an appropriate threshold value on a signal input to the waveform shaping circuit. In the case of rotation, gain adjustment and offset adjustment are automatically executed within the time required to reach a predetermined rotation speed.

  In the gain adjustment, the amplification factor is automatically adjusted so that the signal falls within a predetermined appropriate amplitude range. In the offset adjustment, an appropriate offset value is automatically obtained so that the value of the amplitude center falls within a predetermined range. For example, the timing for executing gain adjustment and offset adjustment processing (hereinafter referred to as initialization processing) is determined by the number of amplitude fluctuations of the output signal.

  Until the signal amplification factor is adjusted to an appropriate value according to the distance between the rotating body and the rotation detection sensor, the output pulse is different from a waveform similar to the shape of the tooth 8 of the rotating body 7 and rotation cannot be detected correctly. there is a possibility.

  As a solution to such a problem, for example, it has been proposed to detect or monitor that the rotating body has been stopped for a predetermined period, and then re-execute gain adjustment and offset adjustment. However, this solution is executed even when the initialization process is substantially unnecessary. Therefore, there is a possibility that the output pulse is disturbed during the initialization process.

  Patent Document 1 proposes another solution. In the technique of Patent Document 1, a displacement sensor or the like that detects physical vibration is separately provided (that is, the displacement sensor is dedicated to detecting vibration that is not rotation). And the output of a rotation detection sensor is compensated based on the vibration detected by this displacement sensor. However, providing an additional sensor complicates the circuit and processing, resulting in an increase in cost.

Patent Document 2 discloses a method and apparatus for providing information from speed and direction sensors. The technology of Patent Document 2 detects the presence of a ferromagnetic material when passing through a sensor. The sensor determines the speed and direction information about the ferromagnet (moving object) as well as information about the environment surrounding the sensor or moving object, such as the gap between the sensor and the moving object, and the environment where the sensor or moving object is installed. Provides information on temperature.
JP 2000-205259 A JP 2005-517928 gazette

  By the way, as one application example, such a rotation detection sensor is used for a device that vibrates like a vehicle. In this case, even when the rotating body is not rotating, the vibration of the device itself to which the rotating body is attached may cause periodic fluctuations in the separation distance between the rotating body and the detection element. . The vibration of the rotating body causes a change in the magnetic flux of the detection element, and the rotation detection sensor may generate an output pulse signal due to the vibration of the rotating body.

  And, in this way, when gain adjustment processing is performed in an environment where fluctuation (vibration noise) due to unexpected vibration appears in the output signal from the magnetic detection element, the change in magnetic flux due to vibration is very small. As a result of gain adjustment, a large gain is obtained.

  Thereafter, when the rotating body rotates, a sufficiently large change in magnetic flux is detected. When this output signal is amplified with an excessive amplification factor, the amplified signal becomes an excessive value exceeding the maximum signal processing range of the integrated circuit. If pulse generation is performed in this state, inconveniences such as disturbing pulse generation timing occur.

  FIG. 5 is a diagram for explaining signal amplification and waveform shaping in the rotation detection device. The left side of FIG. 5 shows a case where the rotating body vibrates without rotating. The right side of FIG. 5 shows the case where the rotating body is rotating. In any case, the detection signal, the amplified signal, and the output pulse after waveform shaping are shown from the top.

  When the rotator is rotating, a detection signal having a somewhat large amplitude is obtained as shown in the upper right waveform in FIG. An appropriate gain is set by the automatic gain control circuit, and is amplified into a waveform that crosses the upper threshold value and the lower threshold value at an appropriate timing. An output pulse corresponding to the rotation is obtained. For example, when the amplified signal exceeds the upper threshold, the rising edge of the output pulse is set. After that, when the signal becomes smaller than the lower threshold, the falling edge of the output pulse is set.

  When the rotating body vibrates without rotating, the amplitude of the detection signal is small as shown in the upper left waveform in FIG. Therefore, a large gain is set by the automatic gain control circuit. When the maximum gain of the amplifier is large and the signal is amplified to the extent that it crosses the threshold, an output pulse can be obtained even though it is not rotating.

  When noise such as vibration is applied to the rotation detection sensor and the gain is set to a large value while the rotating body is not rotating, the rotating body starts to rotate until the gain is adjusted to an appropriate value. Does not provide a correct output pulse waveform.

  Thus, there is a possibility that vibrations and the like may be detected as rotation in addition to the rotation of the rotating body. In addition, it takes time until the amplification factor is adjusted to an appropriate value to detect rotation. In particular, immediately after the rotation detector is turned on, there is a problem that vibration is detected by the maximum gain.

  The present invention has been made in view of the above circumstances, and provides a method for adjusting a signal amplification factor of a rotation detection sensor and a rotation detection device that detect only a rotation signal of a rotating body and do not output a pulse during vibration. With the goal.

  In order to solve the above problems, a signal amplification factor adjustment method for a rotation detection sensor according to a first aspect of the present invention includes a signal detection means for detecting a signal caused by displacement of a rotating body, and an amplification means for amplifying the signal. And an automatic gain control means for automatically adjusting the amplification factor in the amplification means, and a rotation determination step for judging that the rotating body is rotating, the rotation detection sensor comprising: The amplification factor at the time of starting the rotation detection sensor when it is determined in the amplification factor adjustment step for adjusting the amplification factor of the signal in the amplification means and the rotation determination step that the rotating body is rotating. And an amplification factor limiting step of limiting the amplification factor to a predetermined amplification factor range including the amplification factor adjusted in the amplification factor adjustment step.

  Further, the amplification factor limiting step adjusts the amplification factor at the time of starting the rotation detection sensor in the amplification factor adjustment step when it is determined in the rotation determination step that the rotating body is rotating. You may comprise so that it may fix to the amplified gain.

  Furthermore, the rotation detection sensor includes trigger signal input means for inputting a trigger signal, and the rotation determination step is performed when the rotating body is rotating when the trigger signal is input by the trigger signal input means. It is characterized by judging.

  The rotation detecting step includes a counting step for counting the number of output pulses of the rotation detection sensor, and the rotation determining step is such that the rotating body rotates when the number of pulses counted in the counting step exceeds a predetermined value. You may judge.

  Preferably, the counting step counts the number of output pulses per predetermined time, and the rotation determining step counts the number of output pulses per predetermined time counted in the counting step exceeds a predetermined value. Sometimes it is determined that the rotating body is rotating.

  The amplification factor limiting step includes an initialization step of initializing the amplification factor range limited by the amplification factor limiting step to a unique fluctuation range inherent in the automatic gain control means, and the amplification factor limiting step includes the initialization step. After the amplification factor is reset in step, when the rotation determination step determines that the rotating body is first rotating, the amplification factor at the time of starting the rotation detection sensor is adjusted to the amplification factor adjustment. It is good also as a structure restrict | limited to the range of the predetermined gain including the gain adjusted in the step.

  According to a second aspect of the present invention, there is provided a rotation detection device for automatically adjusting a signal detection means for detecting a signal caused by displacement of a rotating body, an amplification means for amplifying the signal, and an amplification factor in the amplification means. A rotation detecting device comprising: automatic gain control means for determining that the rotating body is rotating; and when the rotating determining means determines that the rotating body is rotating. And a gain limiting means for limiting the gain at the time of starting the rotation detection device to a predetermined gain range including the gain adjusted by the automatic gain control means at that time. And

  Furthermore, the amplification factor limiting means, when the rotation determining means determines that the rotating body is rotating, the amplification factor at the time of starting the rotation detecting device, and the automatic gain control at that time You may comprise so that it may fix to the gain adjusted with the means.

  Further, the rotation detection device includes trigger signal input means for inputting a trigger signal, and the rotation determination means is configured to rotate the rotating body when the trigger signal is input by the trigger signal input means. It is characterized by judging.

  The rotation detector includes a counting unit that counts the number of output pulses of the rotation detecting device, and the rotation determining unit rotates the rotating body when the number of pulses counted by the counting unit exceeds a predetermined value. You may judge.

  Preferably, the counting unit counts the number of output pulses per predetermined time, and the rotation determining unit counts the number of output pulses per predetermined time counted by the counting unit exceeds a predetermined value. Sometimes it is determined that the rotating body is rotating.

  The amplification factor limiting unit includes an initialization unit that initializes the range of the amplification factor limited by the amplification factor limiting unit to an inherent variation range inherent in the automatic gain control unit, and the amplification factor limiting unit includes the initialization factor After the amplification factor is reset by the means, when the rotation determination unit first determines that the rotating body is rotating, the amplification factor at the time of starting the rotation detection device is A configuration may be adopted in which the gain is limited to a predetermined gain range including the gain adjusted by the automatic gain control means.

  According to the amplification factor adjusting method and rotation detection device of the rotation detection sensor of the present invention, it is possible to prevent erroneous detection of vibration or the like as rotation of the rotating body when the rotation detection device is activated. And normal rotation can be rapidly detected even at the time of starting.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

(Embodiment 1)
FIG. 1 is a block diagram showing an example of a rotation detection device according to Embodiment 1 of the present invention. As shown in FIG. 1, the rotation detection device 20 includes a rotating body 7, a detection element 1, an amplifier 3, a waveform shaping circuit 4, an automatic gain control circuit 5, a switch 9, and an amplification factor setting circuit 6. The trigger input circuit 11 is provided.

  The rotating body 7 includes many teeth 8 formed of a ferromagnetic material on the outer periphery. A detection element 1 such as a Hall element or a magnetoresistive element is arranged in a magnetic circuit made up of the teeth 8 of the rotating body 7 and the magnet 2. When the ferromagnetic tooth 8 is moved by the rotation of the rotating body 7, the magnetic flux penetrating the detection element 1 changes. The detection element 1 converts a change in magnetic flux penetrating into an electrical signal.

  The signal of the detection element 1 is amplified by the amplifier 3, binarized by the waveform shaping circuit 4, and converted into an output pulse corresponding to the rotation speed of the rotating body 7. The converted output pulse is output from the terminal 10. The reciprocal of the cycle of the output pulse is the rotation speed of the rotator 7, and the output pulse number represents the rotation angle.

  The output of the amplifier 3 is also input to the automatic gain control circuit 5. For example, the automatic gain control circuit 5 adjusts the amplification factor so that the average level of the output of the amplifier 3 is constant. The adjusted amplification factor is input to the amplification factor setting circuit 6. The amplifier 3 has a variable gain. In the amplification factor setting circuit 6, for example, the amplification factor represented by numerical data is converted into a control voltage of the amplifier 3 by D / A conversion or the like, and is input to the amplifier 3 for amplification. Set the rate. The amplification factor setting circuit 6 includes a nonvolatile memory that stores the amplification factor.

  The automatic gain control circuit 5 adjusts the amplification factor to an appropriate value, and the signal of the detection element 1 is amplified to a waveform that crosses the upper threshold value and the lower threshold value at appropriate timing (see FIG. 5). When the amplified signal exceeds the upper threshold, the rising edge of the output pulse is set. After that, when the signal becomes smaller than the lower threshold, the falling edge of the output pulse is set. An output pulse corresponding to the rotation is obtained.

  Noise that fluctuates in the vicinity of the threshold value when the threshold value to be binarized is one and the output pulse is H (High) when the output pulse is larger than the threshold value and L (Low) when the output pulse is smaller than the threshold value As a result, the output pulse varies. Therefore, two threshold values, upper and lower, are provided.

  The rotation detection device 20 includes a switch 9 between the automatic gain control circuit 5 and the amplification factor setting circuit 6 that interrupts the signal path. The trigger input circuit 11 opens the switch 9 by an external trigger signal. The trigger signal may be input by a manual push switch or the like. Alternatively, when it is possible to detect that the vehicle control device is rotating by another method (for example, the voltage and current of a generator coupled to the engine), a trigger signal may be input from the vehicle control device or the like. . The reset input circuit 12 connects the switch 9 with an external reset signal.

  When the trigger signal is input, the switch 9 between the automatic gain control circuit 5 and the gain setting circuit 6 is opened, and the gain of the gain setting circuit 6 is held at the previous value. Thereafter, the amplification factor of the amplifier 3 is fixed to the value stored in the memory. As a result, by inputting a trigger signal when the rotating body 7 is rotating, the rotating body 7 is rotating and can be fixed to an appropriate amplification factor for detecting the rotation.

  The trigger input circuit 11 and the switch 9 constitute rotation determination means. The switch 9 and the amplification factor setting circuit 6 constitute amplification factor limiting means. The rotation detection device 20 normally includes a detection element 1 and an integrated circuit constituting an amplification circuit, an automatic gain control circuit 5, a switch 9, an amplification factor setting circuit 6, and a waveform shaping circuit 4 (integrated). May not have been).

  When the reset signal is input after the trigger signal is input and the amplification factor is fixed, the amplification factor of the amplifier 3 is changed by the automatic gain control circuit 5. When the trigger signal is input again, the amplification factor is fixed.

  For example, when the rotating body 7 attached to the axle or propeller shaft of the vehicle and the detecting element 1 are separated and reassembled, the rotation detecting device 20 is reset and triggered in a rotating state. By inputting a signal, the amplification factor can be fixed to an appropriate value. If the rotating body 7 and the detection element 1 are not reconfigured, or if the conditions hardly change after reconfiguration, the reset input circuit 12 may be omitted.

  Next, the gain adjustment operation of the rotation detection device 20 will be described with reference to FIG. FIG. 2 is a flowchart showing an operation of adjusting the amplification factor of the rotation detection device 20 shown in FIG.

  It is assumed that the rotating body 7 and the detection element 1 are in an initial state assembled or reset. When the rotation detection device 20 is activated, the automatic gain control circuit 5 waits for a trigger signal while adjusting the amplification factor in accordance with the detection signal (step A1, step A2; No). The trigger signal is input when the rotating body 7 is in a normal rotating state and the output pulse is stable.

  When the trigger signal is input (step A2; Yes), the amplification factor is fixed to the value at that time (step A3). That is, since the trigger signal input circuit opens the switch 9 and disconnects the signal path between the automatic gain control circuit 5 and the amplification factor setting circuit 6, the amplification factor of the amplification factor setting circuit 6 is maintained at the previous value. .

  Thereafter, even when the rotation detector 20 is turned off and restarted, the switch 9 remains open and the amplification factor is fixed to the value held in the nonvolatile memory. An appropriate amplification factor for detecting the rotation state is maintained. As a result, an output pulse can be obtained from which rotation can be normally detected from the time of activation.

  As described above, since the amplification factor is fixed when it is determined that the rotating body 7 is rotating, the rotation is correctly detected from the time when the rotation detecting device 20 is started even if it is repeatedly turned on and off. can do. Noise due to vibration or the like is not excessively amplified, and vibration or the like is not detected as rotation. Even when the rotating body 7 and the detection element 1 are reconfigured, the signal amplification factor can be set again and fixed in accordance with the state.

(Modification of Embodiment 1)
Instead of fixing the amplification factor in step A3 of FIG. 2, the amplification factor can be limited to a predetermined range. FIG. 6 is a block diagram illustrating a different example of the rotation detection device according to the first embodiment.

  The rotation detection circuit 20 in FIG. 6 does not have the switch 9 in FIG. 1 but includes a gain range limiting circuit 17 instead. When a trigger signal is input, the gain range limiting circuit 17 limits the amplification factor to a predetermined range with the amplification factor at that time as a center with respect to the automatic gain control circuit 5. Further, when the reset signal is input, the restriction on the amplification factor is released. The gain range limiting circuit 17 constitutes amplification factor limiting means.

  For example, the gain range limiting circuit 17 limits a numerical value that defines the gain variation width of the automatic gain control circuit 5. The automatic gain control circuit 5 controls the gain within a limited range of fluctuation of the gain. The amplification factor setting circuit 6 sets the amplification factor of the amplifier based on the numerical value of the amplification factor set by the automatic gain control circuit 5, so that the amplification factor of the amplifier 3 is in a range limited by the gain range limiting circuit 17. Stay on. As a result, even when the rotating body 7 does not rotate and there is noise such as vibration, the noise is not excessively amplified and vibration or the like is not detected as rotation.

  In the rotation detection circuit 20 of FIG. 6, instead of fixing the amplification factor in step A3 of FIG. 2, the amplification factor is narrowed to a predetermined range. FIG. 7 is a flowchart showing another example of the gain adjustment operation according to the first embodiment. As shown in FIG. 7, in step A4 instead of step A3 in FIG. 2, processing for limiting the range of the variable amplification factor is performed. Here, the range of the amplification factor is narrowed to the range corresponding to the corresponding opponent's rotating body. According to this method, when the step of manufacturing the rotation detection device 20 and the step of combining the rotating body 7 and the rotation detection device 20 are performed at different places or times, a variable amplification factor can be obtained at the manufacturing stage of the rotation detection device 20. This range can be limited in accordance with the target rotating body 7, so that the number of man-hours for final adjustment can be reduced in the subsequent combination process.

(Embodiment 2)
FIG. 3 is a block diagram illustrating an example of the rotation detection device according to the second embodiment of the present invention. In the second embodiment, the output pulse is counted to determine that the rotating body 7 is rotating. As shown in FIG. 3, a counter 14, a determination circuit 15, a determination circuit on / off setting circuit 13, and a trigger generation circuit 16 are provided instead of the trigger signal circuit of the first embodiment.

  The counter 14 counts the output pulses and supplies the number of pulses to the determination circuit 15. The determination circuit on / off setting circuit 13 sets a condition for determining that the rotating body 7 is rotating. For example, there are cases where the number of output pulses after the rotation detection device 20 is turned on exceeds a predetermined number, or cases where the number of output pulses per unit time exceeds a predetermined number. For example, the rotation determination condition may be set from the outside with a dip switch or the like, or may be written into the flash memory or the like from the outside. It can also be configured as a mask ROM.

  The determination circuit 15 compares the condition set by the determination circuit on / off setting circuit 13 with the number of pulses supplied from the counter 14, and activates the trigger generation circuit 16 when the condition is met. When triggered by the determination circuit 15, the trigger generation circuit 16 opens the switch 9 between the automatic gain control circuit 5 and the amplification factor setting circuit 6.

  When the switch 9 between the automatic gain control circuit 5 and the gain setting circuit 6 is opened, the gain of the gain setting circuit 6 is held at the previous value. Thereafter, the amplification factor of the amplifier 3 is fixed to the value stored in the memory. Therefore, by setting a condition for the number of pulses that can be determined that the rotating body 7 is rotating, the rotating body 7 is rotating and can be fixed to an appropriate amplification factor in order to detect the rotation.

  The determination circuit 15 and the determination circuit on / off setting circuit 13 constitute rotation determination means. The trigger generation circuit 16, the switch 9, and the amplification factor setting circuit 6 constitute amplification factor limiting means. The rotation detection device 20 usually includes a detection element 1, an amplification circuit, an automatic gain control circuit 5, a switch 9, an amplification factor setting circuit 6, a waveform shaping circuit 4, a counter 14, a determination circuit 15, and a determination circuit on / off setting circuit. 13 and one integrated circuit constituting the trigger generation circuit 16 (there may not be integrated).

  Once the trigger generation circuit 16 is activated and the amplification factor is fixed, when a reset signal is input from the reset input circuit 12, the switch 9 is closed and the amplification factor of the amplifier 3 is set to the automatic gain control circuit 5 It will change depending on the situation. Further, the amplification factor is fixed when the trigger generation circuit 16 is activated from the determination circuit 15. The fact that the reset input circuit 12 is not necessary is the same as in the first embodiment.

  Next, the gain adjustment operation of the rotation detection device 20 will be described with reference to FIG. FIG. 4 is a flowchart showing an operation of adjusting the amplification factor of the rotation detection device 20 shown in FIG.

  It is assumed that the rotating body 7 and the detection element 1 are in an initial state assembled or reset. When the rotation detection device 20 is activated, the automatic gain control circuit 5 counts output pulses while adjusting the amplification factor according to the detection signal (step B1, step B2; No).

  When the number of output pulses matches the set condition (for example, when a predetermined number is exceeded) (step B2; Yes), the amplification factor is fixed to the value at that time (step B3). That is, the determination circuit 15 activates the trigger signal generation circuit 16, and the trigger signal generation circuit 16 opens the switch 9. Since the signal path between the automatic gain control circuit 5 and the amplification factor setting circuit 6 is disconnected, the amplification factor of the amplification factor setting circuit 6 is maintained at the previous value.

  Thereafter, even when the rotation detector 20 is turned off and restarted, the switch 9 remains open and the amplification factor is fixed to the value held in the nonvolatile memory. An appropriate amplification factor for detecting the rotation state is maintained. As a result, an output pulse can be obtained from which rotation can be normally detected from the time of activation.

(Modification of Embodiment 2)
In step B1 of FIG. 4, instead of counting the cumulative number of output pulses, the number of output pulses per predetermined time can be counted. FIG. 8 is a flowchart showing another example of the gain adjustment operation according to the second embodiment. As shown in FIG. 8, instead of step B1 in FIG. 4, the number of pulses within a certain time is counted in step B4. In this case, the amplification factor is fixed when the specified rotational speed is exceeded. In this case, the counter 14 counts the number of pulses per fixed time. Alternatively, the determination circuit 15 or the determination circuit on / off setting circuit 13 may reset the counter 14 at regular intervals.

  In this method, the predetermined number of pulses to be compared in step B2 is set to a numerical value corresponding to a specified frequency smaller than the rotation frequency that can be reached during actual use. When the rotation detection device 20 is inspected alone, the rotation detection device 20 is inspected at a frequency smaller than the specified frequency. In this way, since the rotation rate is fixed when the rotation detection device 20 is combined with the rotating body 7 and the rotation frequency close to that in actual use is reached, the amplification rate is fixed after the rotation detection device 20 is inspected alone. There is no need to reset pinning.

  According to this method, when the step of manufacturing the rotation detecting device 20 and the step of combining the rotating body 7 and the rotation detecting device 20 are performed at different places or times, the amplification rate is fixed in the subsequent combining step. There is no need to do. Further, the reset input circuit 12 can be omitted.

  As described above, since the amplification factor is fixed when it is determined that the rotating body 7 is rotating, the rotation is correctly detected from the time when the rotation detecting device 20 is activated even if the on / off is repeated thereafter. be able to. Noise due to vibration or the like is not excessively amplified, and vibration or the like is not detected as rotation. Even when the rotating body 7 and the detection element 1 are reconfigured, the signal amplification factor can be set again and fixed in accordance with the state.

  According to the method of the present invention, there is no need to provide another sensor or the like in the rotation detection device 20 that can set a wide separation distance from the rotating body 7 that can be detected. With a simple configuration, it is possible to realize the rotation detection device 20 that can stably detect rotation from the time of startup.

  Note that the method of the present invention can be applied not only to rotation detection but also to detection of linear motion. That is, for a linear motion body driven by a linear actuator, if the output of the detection element that detects linear motion includes a signal such as vibration of the linear motion body, the signal amplification factor is linear The gain is fixed at the time when Since the amplification factor is fixed when it is determined that the rectilinear moving body is moving linearly, the rectilinear movement can be correctly detected from the time when the detection device is activated even if ON / OFF is repeated thereafter. And noise due to vibration or the like is not excessively amplified, and vibration or the like is not detected as a straight movement.

  Needless to say, the rotation detection device of the present invention can be applied to a rotating body such as a pinion or a worm when the rotation is converted into a linear motion by a rack and pinion or a rack and worm. In addition, the hardware configuration and the flowchart described above are merely examples, and can be arbitrarily changed and modified.

It is a block diagram which shows an example of the rotation detection apparatus which concerns on Embodiment 1 of this invention. It is a flowchart which shows the operation | movement of the gain adjustment which concerns on Embodiment 1 of this invention. It is a block diagram which shows an example of the rotation detection apparatus which concerns on Embodiment 2 of this invention. It is a flowchart which shows the operation | movement of the gain adjustment which concerns on Embodiment 2 of this invention. It is a figure explaining amplification of a signal and waveform shaping in a rotation detector. It is a block diagram which shows the example from which the rotation detection apparatus which concerns on Embodiment 1 differs. 6 is a flowchart showing another example of the gain adjustment operation according to the first embodiment. 10 is a flowchart illustrating an example of a different operation of gain adjustment according to the second embodiment.

Explanation of symbols

1 detection element (signal detection means)
3 Amplifier (amplification means)
4 Waveform shaping circuit 5 Automatic gain control circuit (automatic gain control means)
6 Amplification factor setting circuit (Amplification factor limiting means)
7 Rotating body 8 Teeth 9 Switch (Amplification factor limiting means)
11 Trigger input circuit (trigger signal input means)
12 reset input circuit 13 determination circuit ON / OFF setting circuit (rotation determination means)
14 Counter (Counting means)
15 determination circuit (rotation determination means)
16 Trigger generation circuit (amplification factor limiting means)
17 Gain range limiting circuit (amplification limiting means)
20 Rotation detector

Claims (12)

Signal amplification of a rotation detection sensor comprising signal detection means for detecting a signal caused by displacement of the rotating body, amplification means for amplifying the signal, and automatic gain control means for automatically adjusting the amplification factor in the amplification means A rate adjustment method,
A rotation determining step for determining that the rotating body is rotating;
An amplification factor adjustment step for adjusting the amplification factor of the signal in the amplification means;
In the rotation determination step, when it is determined that the rotating body is rotating, the amplification factor at the time of starting the rotation detection sensor is a predetermined amplification factor including the amplification factor adjusted in the amplification factor adjustment step An amplification factor limiting step to limit the range to
A method for adjusting a signal amplification factor of a rotation detection sensor, comprising:   In the amplification factor limiting step, when it is determined in the rotation determination step that the rotating body is rotating, the amplification factor at the time of starting the rotation detection sensor is adjusted by the amplification factor adjustment step. The method for adjusting a signal amplification factor of a rotation detection sensor according to claim 1, wherein the signal amplification factor is fixed to a rate. The rotation detection sensor includes trigger signal input means for inputting a trigger signal,
2. The signal amplification of the rotation detection sensor according to claim 1, wherein the rotation determination step determines that the rotating body is rotating when the trigger signal is input by the trigger signal input unit. Rate adjustment method. A counting step of counting the number of output pulses of the rotation detection sensor;
2. The rotation detection sensor according to claim 1, wherein the rotation determining step determines that the rotating body is rotating when the number of pulses counted in the counting step exceeds a predetermined value. Signal gain adjustment method. The counting step counts the number of output pulses per predetermined time,
The rotation determining step determines that the rotating body is rotating when the number of output pulses per predetermined time counted in the counting step exceeds a predetermined value. 5. A method for adjusting a signal amplification factor of a rotation detection sensor according to 4. An initialization step of initializing the range of the amplification factor limited in the amplification factor limiting step to a unique variation range inherent in the automatic gain control means;
In the amplification factor limiting step, after the amplification factor is reset in the initialization step, and when the rotation determination step first determines that the rotating body is rotating, the rotation detection sensor is activated. Limiting the amplification factor to a predetermined amplification factor range including the amplification factor adjusted in the amplification factor adjustment step,
The method for adjusting the signal amplification factor of the rotation detection sensor according to claim 1. A rotation detection device comprising: signal detection means for detecting a signal caused by displacement of a rotating body; amplification means for amplifying the signal; and automatic gain control means for automatically adjusting an amplification factor in the amplification means. ,
Rotation determining means for determining that the rotating body is rotating;
When the rotation determination unit determines that the rotating body is rotating, the amplification factor at the time of activation of the rotation detection device includes a predetermined value including the amplification factor adjusted by the automatic gain control unit at that time. An amplification factor limiting means for limiting the amplification factor to a range;
A rotation detection device comprising:   When the rotation determination unit determines that the rotating body is rotating, the amplification factor limiting unit determines the amplification factor at the time of starting the rotation detection device at that time by the automatic gain control unit. The rotation detection device according to claim 7, wherein the rotation detection device is fixed to the adjusted amplification factor. The rotation detection device includes trigger signal input means for inputting a trigger signal,
The rotation detection device according to claim 7, wherein the rotation determination unit determines that the rotating body is rotating when the trigger signal is input by the trigger signal input unit. Comprising a counting means for counting the number of output pulses of the rotation detecting device;
The rotation detection device according to claim 7, wherein the rotation determination unit determines that the rotating body is rotating when the number of pulses counted by the counting unit exceeds a predetermined value. The counting means counts the number of output pulses per predetermined time,
The rotation determining means determines that the rotating body is rotating when the number of output pulses per predetermined time counted by the counting means exceeds a predetermined value.
The rotation detection device according to claim 10. Initializing means for initializing the range of the amplification factor limited by the amplification factor limiting unit to a inherent variation range inherent in the automatic gain control unit;
The amplification factor limiting unit is configured to start the rotation detection device when the rotation determination unit first determines that the rotating body is rotating after the amplification unit is reset by the initialization unit. Limiting the amplification factor to a predetermined amplification factor range including the amplification factor adjusted by the automatic gain control means at that time,
The rotation detection device according to claim 7.

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