JP4524461B2 - Sensor self-diagnosis method and apparatus using jump element - Google Patents

Description

  The present invention relates to a sensor self-diagnosis method and apparatus using jump elements.

It is necessary in the fields of automatic control and various fields such as electric and electronic devices to detect the presence / absence of an object, the moving position and moving speed of a moving object, and the like. Conventionally, various sensors that can be used in such fields have been developed and used. Among these sensors, there are general ones such as a position sensor, an angle sensor, and a speed sensor using an electromagnetic pickup, a magnetoresistive element, a Hall element, an optical element, a sound wave element, and the like. However, the electromagnetic pickup has a problem that the generated voltage is low when the moving speed of the object to be detected is extremely low, and it is in the vicinity of the noise level. There is a problem that a separate power source is required for energization, and no power source can be used.
As an alternative to the sensor having these problems, there is a sensor using a jump element as disclosed in, for example, Japanese Patent Application Laid-Open No. 11-94588 and Japanese Patent Application Laid-Open No. 11-195964 by the present applicant. It has been developed. A sensor using these jump elements is generally a magnetic element that can cause a large Barkhausen jump (hereinafter referred to as a jump element), and detection means (hereinafter referred to as a pickup coil) disposed in association with the jump element. ), And a working magnetic field generating means for applying a magnetic field that can move relative to the jump element according to the movement of the detected object and can cause a large Barkhausen jump to the jump element. Sensors using these jump elements can detect the moving position and moving speed of an object regardless of the moving speed of the object to be detected, can provide extremely high resolution, and can be powered off. It is a very wide application field.
However, one of the features of the sensor using these jump elements is that it only generates a pulse output signal only when a predetermined condition is met, and does not generate any output in other states due to its operating principle. It is what you are trying. Therefore, in other states, whether the detected object is present or not, what is the current state of the sensor or the jump element itself, and whether the sensor using the jump element is normal It is difficult to determine whether it is in a state where it can operate or is in a defective / abnormal state.
To elaborate on this point, it is necessary to detect the rotation of medium / high-speed rotating bodies, for example, and the objects will always appear without repeating each other. For example, in the case of detecting the number of mass-produced products in a conveyance line, the presence or absence of an object is caused by the occurrence of a pulse output. Abnormalities can also be confirmed. However, for example, when an object is moving, present, or absent irregularly, such as opening or closing of a window or door as an object to be detected or an irregular approach or presence of an object, or when the time interval is relatively long Therefore, it is not always possible to reliably check the state of the “current” object, the jump element itself, and the sensor itself using the jump element. In addition, when the devices that have been turned off are turned on again, the initial state of the detected object, the jump element itself, and the sensor using the jump element, and the jump element are used. It is difficult to determine whether the sensor is in a state in which it can operate normally, or in a defective / abnormal state.
This is because the change in the output current that occurs when power is always applied, such as various sensors as described above other than the sensor using a jump element, such as a magnetoresistive element, a Hall element, an optical element, and a sonic element. The presence or absence of the target object and the normality / abnormality of the sensor itself are completely different from those that can always be confirmed by the output.
Accordingly, an object of the present invention is to provide a sensor self-diagnosis method and apparatus capable of solving the problems of the sensor using the jump element as described above.

The present invention relates to the presence / absence of an object (detection target object or some action object) and the current state and operable state / defective / abnormal state of the sensor or jump element itself, etc. It is intended to provide a method and apparatus that can be verified.
According to one aspect of the present invention, in a self-diagnosis method for a sensor using a jump element, an excitation signal sufficient to change the state of the magnetic history of the jump element is applied to the jump element. A self-diagnosis method is provided that receives the output signal of the sensor and detects the state of the sensor by identifying the output signal.
According to another aspect of the present invention, in a self-diagnosis device for a sensor using a jump element, an excitation signal for applying an excitation signal sufficient to change the state of the magnetic history of the jump element to the jump element. A self-diagnosis apparatus comprising: a signal applying unit; and an output signal identification unit that receives an output signal of the sensor, identifies the output signal, and outputs a state signal indicating the state of the sensor Is done.
According to one embodiment of the present invention, the excitation signal applying unit applies an excitation signal directly to the pickup coil of the sensor.
According to another embodiment of the present invention, the excitation signal applying unit generates an excitation signal to be applied to the excitation signal applying coil disposed in the vicinity of the jump element and the excitation signal applying coil. An excitation signal generating circuit.
According to still another embodiment of the present invention, the output signal identification unit is connected to an output terminal of a pickup coil of the sensor.
According to still another embodiment of the present invention, the excitation signal has an alternating current waveform for at least one cycle changing from one polarity to the other polarity.
According to still another embodiment of the present invention, the excitation signal has the same magnetic history state of the jump element after application of the excitation signal as the magnetic history state of the jump element before application of the excitation signal. It is like that.
Next, based on an accompanying drawing, the present invention is explained in detail about an embodiment and an example of the present invention.

FIG. 1 is a diagram for explaining the relationship between a magnetic history (hysteresis) curve of a jump element and a generated pulse output.
FIG. 2 is a block diagram showing a configuration example of a self-diagnosis apparatus as an embodiment of the present invention for carrying out a sensor self-diagnosis method using jump elements according to the present invention.
FIG. 3 is a diagram showing a waveform example of an excitation signal used for self-diagnosis of the present invention.
FIG. 4 is a diagram for explaining an output curve output in the self-diagnosis of the present invention.
FIG. 5 is a diagram for explaining a pulse train output in accordance with the state of the sensor when a certain excitation signal is used in the self-diagnosis of the present invention.
FIG. 6 is a diagram for explaining a pulse train output according to the state of the sensor when another excitation signal is used in the self-diagnosis of the present invention.
FIG. 7 is a diagram for explaining a pulse train output according to the state of the sensor when another excitation signal is used in the self-diagnosis of the present invention.
FIG. 8 illustrates a pulse train output according to the state of the sensor when another excitation signal is used in the self-diagnosis of the present invention, and for returning the sensor to the state before the self-diagnosis after the self-diagnosis. It is a figure for demonstrating this method.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing embodiments and examples of the present invention, referring to FIG. 1 of the accompanying drawings, a magnetic hysteresis curve of a jump element used in a sensor to be self-diagnosed. And the pulse output output in the self-diagnosis will be described. Generally, the jump element has a magnetic history as exemplified by a magnetic history curve in the upper part of FIG. As shown in this magnetic history curve, the state of the jump element itself is the moment the pulse output is generated in relation to the pulse output corresponding to the lower part of the magnetic history curve, that is, reverse pulse generation. Except for the point (α point) and the positive pulse generation point (β point), the state is always in one of the states (1) to (4) or the region.
In FIG. 1, the region {circle around (1)} is a state or region where a magnetic field having a reverse polarity is applied and a state or region where a magnetic field larger than the α point is applied. The region {circle around (2)} is the state or region from the region {circle around (1)} to the point immediately before the point β after the applied magnetic field weakens and exceeds the point α. The region {circle around (3)} is a state or region after the β point is exceeded and still having a positive magnetic field applied. The region {circle around (4)} is the state or region from the region {circle around (3)} to the point just before the point α after the magnetic field applied is weakened and exceeds the point β.
Next, a configuration example of a self-diagnosis device for carrying out the self-diagnosis method of the present invention will be described. FIG. 2 (a) schematically shows a configuration of an embodiment of a sensor self-diagnosis device using a jump element according to the present invention, and FIG. 2 (b) shows a jump element according to the present invention. 1 schematically shows a configuration of another embodiment of a sensor self-diagnosis device using a sensor. The embodiment of FIG. 2 (a) is a type in which an excitation signal for self-diagnosis is directly applied to a pickup coil 2 as detection means arranged in association with a jump element 1 of a sensor to be self-diagnosis. belongs to. The self-diagnosis device of this embodiment includes an excitation signal applying unit 10 connected between the output terminals 2A and 2B of the pickup coil 2 and a pulse output identification unit 20. The embodiment of FIG. 2 (b) is of a type in which an excitation signal for self-diagnosis is applied to the jump element 1 by an excitation signal applying coil 12A arranged in the vicinity of the jump element 1 of the sensor to be self-diagnosed. is there. The self-diagnosis device of this embodiment includes an excitation signal application unit 10A comprising an excitation signal generation circuit 11A and an excitation signal application coil 12A, and a pulse output identification unit 20A connected between the output terminals 2A and 2B of the pickup coil 2. Is provided.
FIG. 3 is a diagram showing a waveform example of an excitation signal to be applied to the pickup coil 2 or the excitation signal applying coil 12A for sensor self-diagnosis using the jump element 1. FIG. The waveform of this excitation signal is a rectangular current waveform for one cycle that changes from positive to negative, and the amplitude of the state of the jump element 1 described with reference to FIG. It is sufficient to shift from point to α point. Therefore, the excitation signal applying unit 10 and the excitation signal generating circuit 11A may be arbitrary as long as they can generate such an excitation signal, and known means can be applied.
FIG. 4 (a) shows a pickup when the excitation signal of FIG. 3 is applied to the pickup coil 2 when the jump element 1 is in the region {circle around (1)} or {circle around (2)} described with reference to FIG. The example of the self-diagnosis output waveform output between the output terminals 2A and 2B of the coil 2 is shown. In this case, as shown in FIG. 4A, the self-diagnosis output waveform has a form in which the waveform of the pulse output by the large Barkhausen jump of the jump element 1 is superimposed on the output waveform by the excitation signal. Yes.
FIG. 4B shows a case where the excitation signal of FIG. 3 is applied to the excitation signal applying coil 12A when the jump element 1 is in the region {circle around (1)} or {circle around (2)} described with reference to FIG. 4 shows an example of a self-diagnosis output waveform output between the output terminals 2A and 2B of the pickup coil 2. In this case, as shown in FIG. 4B, the self-diagnosis output waveform has only a waveform of a pulse output by the large Barkhausen jump of the jump element 1.
Next, the operation principle of the self-diagnosis according to the present invention will be described in more detail with reference to FIGS. First, FIG. 5 shows a case where the excitation signal used for self-diagnosis has a waveform as illustrated in FIG. 3, and the pickup coil 2 according to the magnetic history state of the jump element 1 of the sensor. The self-diagnosis output waveforms output to the output terminals 2A and 2B of FIG. 5A shows the excitation signal waveform to be used, and FIG. 5B shows the state of the magnetic history of the jump element 1 before applying the excitation signal with respect to FIG. FIG. 5C shows the self-diagnosis waveform obtained when the region is in the region {circle around (1)} described above. FIG. 5C shows the state of the magnetic history of the jump element 1 before applying the excitation signal. FIG. 5D shows an example of a self-diagnosis waveform obtained when the region is in the region {circle around (2)} described with reference to the figure. FIG. 5 (d) shows the state of the magnetic history of the jump element 1 before applying the excitation signal. FIG. 5 (e) shows an example of a self-diagnosis waveform obtained when the region is in the region {circle around (3)} described with reference to FIG. 1, and FIG. The state is in the area of (4) described with reference to FIG. It illustrates a self-diagnostic waveform obtained when. As can be understood by comparing these self-diagnosis output waveforms, it is possible to distinguish and know which region the state of the magnetic history of the jump element 1 was in by using these waveforms. Therefore, the pulse output identification unit 20 or 20A connected to the output terminals 2A and 2B of the pickup coil 2 recognizes the pattern of the output pulse output thereto and outputs a status signal corresponding to the pattern. You can know the state of. Here, the state signal output from the pulse output identification unit 20 or 20A is, for example, whether the jump element 1 is in the state (1), (2), or (3). It may be arbitrary as long as it indicates whether it is in the state of (4) or the like. The pulse output identification unit 20 or 20A may be any unit as long as it can recognize and recognize the pattern of output pulses, and may be a known unit of that type.
As can be seen by comparing the output pulse patterns of FIGS. 5 (b) and 5 (c), when the excitation signal shown in FIG. 5 (a) is used, the jump element 1 is It cannot be distinguished whether it was in the area (1) or the area (2). The output waveform of FIG. 5 is shown as being obtained in the embodiment of FIG. 2 (b), but the output waveform obtained in the embodiment of FIG. 2 (a) is also shown. Since this is merely superimposed on the output waveform of the excitation signal (see the waveform in FIG. 4A), these will not be described repeatedly. The same applies to the description of the example of FIGS.
Next, FIG. 6 shows the magnetic field of the jump element 1 of the sensor when the excitation signal used for self-diagnosis has a waveform that is 180 degrees out of phase with the waveform illustrated in FIG. The self-diagnosis output waveforms output to the output terminals 2A and 2B of the pickup coil 2 in accordance with the history state are respectively illustrated. 6A shows the excitation signal waveform to be used (the waveform of FIG. 3 is 180 degrees out of phase with that of FIG. 3), and FIG. 6B shows the application of the excitation signal. FIG. 6C shows an example of a self-diagnosis waveform obtained when the magnetic history state of the jump element 1 is in the region {circle around (1)} described with reference to FIG. FIG. 6 (d) shows an example of a self-diagnosis waveform obtained when the state of magnetic history of the jump element 1 before application is in the region {circle around (2)} described with reference to FIG. FIG. 6 (e) shows an example of a self-diagnosis waveform obtained when the state of the magnetic history of the jump element 1 before the signal is applied is in the region (3) described with reference to FIG. The state of the magnetic history of the jump element 1 before applying the excitation signal It illustrates a self-diagnostic waveform obtained when there was the ▲ 4 ▼ regions described in relation to Figure 1. As can be understood by comparing these self-diagnosis output waveforms, it is possible to distinguish and know which region the state of the magnetic history of the jump element 1 was in by using these waveforms.
As can be seen by comparing the output pulse patterns of (d) and (e) of FIG. 6, when the excitation signal shown in (a) of FIG. It cannot be distinguished whether it was in the area (3) or the area (4).
As can be seen from the above description, the jump element 1 was in the area (1) or (2), or was it in the area (3) or (4). In order to clearly distinguish between the excitation signal used in FIG. 5 and the excitation signal used in FIG. 6, a self-diagnosis may be performed.
Next, FIG. 7 shows the output terminal of the pickup coil 2 according to the state of the magnetic history of the jump element 1 of the sensor when an excitation signal having another waveform is used as the excitation signal used for self-diagnosis. The self-diagnosis output waveforms output to 2A and 2B are respectively illustrated. 7A shows the excitation signal waveform used, and FIG. 7B shows the state of the magnetic history of the jump element 1 before application of the excitation signal. FIG. 7 (c) shows the state of the magnetic history of the jump element 1 before the excitation signal is applied. FIG. 7D shows an example of a self-diagnosis waveform obtained when the region is in the region {circle around (2)} described with reference to FIG. 1. FIG. 7 (d) shows the state of magnetic history of the jump element 1 before the excitation signal is applied. Exemplifies a self-diagnostic waveform obtained when it is in the region {circle around (3)} described with reference to FIG. 1, and FIG. 7 (e) shows the magnetic history of the jump element 1 before the excitation signal is applied. Is in the area (4) described with reference to FIG. It illustrates a self-diagnostic waveform obtained when Tsu. As can be understood by comparing these self-diagnosis output waveforms, it is possible to distinguish and know which region the state of the magnetic history of the jump element 1 was in by using these waveforms.
Next, FIG. 8 shows the output terminal of the pickup coil 2 in accordance with the state of the magnetic history of the jump element 1 of the sensor when an excitation signal having another waveform is used as the excitation signal used for self-diagnosis. The self-diagnosis output waveforms output to 2A and 2B are respectively illustrated. 8 (a) shows the excitation signal waveform used, and FIG. 8 (b) shows the state of the magnetic history of the jump element 1 before applying the excitation signal. FIG. 8 (c) shows the state of the magnetic history of the jump element 1 before applying the excitation signal. FIG. 8 (d) shows an example of a self-diagnosis waveform obtained when the region is in the region {circle around (2)} described with reference to FIG. 1. FIG. Exemplifies a self-diagnosis waveform obtained when it is in the region {circle around (3)} described with reference to FIG. 1. FIG. 8 (e) shows the magnetic history of the jump element 1 before the excitation signal is applied. Is in the area (4) described with reference to FIG. It illustrates a self-diagnostic waveform obtained when Tsu. As can be understood by comparing these self-diagnosis output waveforms, it is possible to distinguish and know which region the state of the magnetic history of the jump element 1 was in by using these waveforms.
If an excitation signal having a waveform as shown in FIG. 8 (a) is used, the state of the magnetic history of the jump element 1 of the sensor is the same as that before applying the excitation signal after applying the excitation signal for self-diagnosis. It is convenient to make it the same as the state. That is, as shown in FIGS. 8 (b), (d), and (e) (the symbol attached to the right end of each output pulse waveform indicates the state of the magnetic history of the jump element after applying the excitation signal. The magnetic history state of the jump element after application of the excitation signal is the same as the magnetic history state of the jump element before application of the excitation signal. However, in the case of FIG. 8C, the magnetic history state of the jump element is made the same as the original state by further applying an excitation signal as shown on the right side thereof.
In the above description, the waveform of the output pulse output to the output terminal of the pickup coil as a result of applying the excitation signal for self-diagnosis is normal for each component of the sensor that is performing the self-diagnosis. It is as. However, in the case of a sensor performing self-diagnosis, for example, when the pickup coil is disconnected, no pulse will be output to the output terminal of the pickup coil even if an excitation signal is applied. Because, for example, when the jump element of the sensor is broken or when other circuits or elements are abnormal, the predetermined pulse will not be output to the output terminal of the pickup coil. By grasping this point in advance, it is possible to identify and detect various failures of the sensor.
In the embodiment described above, a rectangular alternating current waveform is used as the waveform of the excitation signal. However, the present invention is not limited to this, and an arbitrary alternating current waveform such as a sine wave, a sawtooth wave, or a triangular wave is used. Can also be used. However, when the rectangular AC current waveform is used, the excitation signal rises and falls sharply, and the shape of the output pulse generated accordingly can be clearly distinguished. This is advantageous in that it can be performed more easily and accurately.

  According to the present invention, it is possible to easily confirm the current state, operable state, defect / abnormal state, etc. of the sensor using the jump element by simply applying the excitation signal. Even when a failure occurs, it is possible to easily determine whether the cause of the failure is in the sensor itself or in other components of the device.

Claims (7)

In a self-diagnosis method for a sensor using a jump element, an excitation signal sufficient to change a state of magnetic history of the jump element is applied to the jump element, an output signal of the sensor is received, Detecting the state of the sensor by identifying the output signal ;
The excitation signal is such that the state of magnetic history of the jump element after application of the excitation signal is the same as the state of magnetic history of the jump element before application of the excitation signal. Diagnosis method.   The self-diagnosis method according to claim 1, wherein the excitation signal has an alternating current waveform for at least one cycle changing from one polarity to the other polarity. In a self-diagnosis device for a sensor using a jump element, an excitation signal applying unit for applying an excitation signal sufficient to change the state of the magnetic history of the jump element to the jump element, and an output signal of the sensor And an output signal identification unit for identifying the output signal and outputting a status signal indicating the status of the sensor ,
The excitation signal is such that the state of magnetic history of the jump element after application of the excitation signal is the same as the state of magnetic history of the jump element before application of the excitation signal , A self-diagnosis device built in the sensor system for diagnosing the sensor itself .   The self-diagnosis apparatus according to claim 3, wherein the excitation signal applying unit applies an excitation signal directly to a pickup coil of the sensor.   The excitation signal application unit includes an excitation signal application coil disposed in the vicinity of the jump element, and an excitation signal generation circuit for generating an excitation signal to be applied to the excitation signal application coil. Self-diagnosis device.   The self-diagnosis device according to claim 3, wherein the output signal identification unit is connected to an output terminal of a pickup coil of the sensor.   The self-diagnosis device according to any one of claims 3 to 6, wherein the excitation signal has an alternating current waveform for at least one cycle changing from one polarity to the other polarity.

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