JP7192247B2 - Position detector - Google Patents

Description

The present invention relates to a position detection device.

As a device of this type, for example, one described in Patent Document 1 is known. The device described in Patent Document 1 is provided with a magnetic sensor for detecting changes in the magnetic field accompanying movement of the magnet. This device calculates the output voltage of the magnetic sensor and detects the position of the magnet, that is, the shift position, based on the calculation result.

JP 2011-105166 A

In this type of device, the detection results can change over time, ie, endurance fluctuations. In general, a reference value is required to control endurance variation. However, for example, in a position detection device mounted on a vehicle, the output itself of the sensor element used serves as a reference for the physical quantity used for position detection. Therefore, it has been difficult to control the durability variation.

The present invention has been made in view of the circumstances exemplified above. That is, it is an object of the present invention to satisfactorily suppress changes in detection results over time, that is, variations in endurance.

A position detection device (1) according to claim 1 is configured to detect the position of a position detection target (3).
This position detection device
a sensor element unit (2) configured to output a sensor signal, which is an electrical signal corresponding to the position;
a detection value output unit (6) configured to output a detection value corresponding to the detection result of the position based on the sensor signal;
with
The detected value output unit is
a provisional detection value acquiring unit (63) provided to acquire a provisional detection value corresponding to the provisional detection result of the position by processing the sensor signal;
An initial provisional detection value, which is the provisional detection value acquired by the provisional detection value acquisition unit, corresponding to the initial position, which is the position at the time of system startup of the position detection target, and the detection value corresponding to the initial position. A calculation processing unit (65) provided to determine whether or not to correct the provisional detection value over time by performing calculation processing based on an initial standard value preset as a standard value of
provided to generate the detection value by performing the temporal correction on the provisional detection value when the arithmetic processing unit determines that the provisional detection value needs to be corrected with time; a correction unit (66);
with
The provisional detection value obtaining unit performs non-temporal correction, which is different from the temporal correction, on the pre-correction provisional detection value obtained by processing the sensor signal, so that the temporal correction is It is configured to acquire the temporary detection value that has not been detected.

In addition, in each column of the application documents, when each element is given a reference sign with parentheses, the reference sign simply indicates the corresponding relationship between the same element and the specific configuration described in the embodiment described later. An example is shown. Therefore, the present invention is not limited by the description of such reference numerals.

1 is a schematic diagram showing a schematic configuration of a position detection device according to an embodiment; FIG. 2 is a block diagram showing a schematic configuration of the position detection device shown in FIG. 1; FIG. 3 is a graph showing an outline of the operation of the position detection device shown in FIG. 2; 3 is a flow chart showing an outline of the operation of the position detection device shown in FIG. 2;

(embodiment)
BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described based on the drawings. It should be noted that if various modifications applicable to one embodiment are inserted in the middle of a series of explanations regarding the embodiment, there is a risk that the understanding of the embodiment will be hindered. It is described collectively after the explanation.

(composition)
First, referring to FIG. 1, a schematic configuration of a position detection device 1 according to an embodiment will be described. For convenience of explanation, right-handed XYZ orthogonal coordinates are set as shown in FIG. The position detection device 1 according to this embodiment is configured to detect the relative position of the sensor element portion 2 and the position detection target 3 in the X-axis direction in the figure. For simplification of explanation, the relative position of the sensor element unit 2 and the position detection target 3 in the X-axis direction in the figure is hereinafter simply referred to as "the position of the position detection target 3". The position detection object 3 is provided with a movable magnet.

In this embodiment, the position detection device 1 is a shift position detection device mounted on an automatic transmission vehicle, and is configured to generate a detection output corresponding to the shift position. Specifically, the position detection object 3 is connected to a gear shift lever 4 provided on the vehicle via a connecting mechanism 5 . The position detection object 3 is provided so as to move relative to the sensor element portion 2 in the X-axis direction in the figure according to the operation state of the shift lever 4 .

The sensor element section 2 has a plurality of magnetic detection elements 20 . In this embodiment, the magnetic detection element 20 is a TMR element, which is a semiconductor sensor element, and is configured such that the electric resistance value changes according to the change in the magnetization direction of the free layer due to the external magnetic field. TMR is an abbreviation for Tunnel Magneto-Resistance.

Referring to FIG. 2, the sensor element section 2 has a configuration in which a plurality of magnetic detection elements 20 are bridge-connected. Specifically, the sensor element section 2 has a first bridge circuit 21 and a second bridge circuit 22 .

The first bridge circuit 21 and the second bridge circuit 22 are half bridge circuits formed by a plurality of magnetic detection elements 20, and are configured to output sensor signals, which are electric signals corresponding to the position of the position detection target 3. there is The first bridge circuit 21 is provided to generate a sinusoidal output when the position detection object 3 continuously moves in the X-axis direction in the drawing at a constant speed. The second bridge circuit 22 is provided so as to generate a cosine wave-shaped output when the position detection target 3 continuously moves in the X-axis direction in the figure at a constant speed.

Referring to FIG. 2 , the position detection device 1 further includes a detection value output section 6 . The detection value output unit 6 is configured to output a detection value corresponding to the detection result of the position of the position detection target 3 based on the sensor signals output by the first bridge circuit 21 and the second bridge circuit 22. there is Specifically, in the present embodiment, the detected value output unit 6 includes an interface 61, an AD converter 62, a temporary detected value acquisition unit 63, a memory 64, an arithmetic processing unit 65, and a temporal correction unit 66. , a selector 67 and an output terminal 68 .

The interface 61 is electrically connected to the first bridge circuit 21 and the second bridge circuit 22 in parallel. The interface 61 is provided so as to alternately acquire the sensor output of the first bridge circuit 21 and the sensor output of the second bridge circuit 22 in a time-division manner and input them to the AD converter 62 . The AD converter 62 is provided so as to analog/digital convert the input sensor output and input the conversion result to the provisional detection value acquisition section 63 .

The provisional detection value acquisition unit 63 acquires a provisional detection value corresponding to the provisional detection result of the position of the position detection target 3 by processing the input signal, that is, the sensor signal analog/digital converted by the AD converter 62 . It is designed to Specifically, the temporary detection value acquisition unit 63 has a codec 631 and a non-temporal correction unit 632 .

The codec 631 is provided so as to process the sensor signal analog/digital converted by the AD converter 62 to acquire the pre-correction provisional detection value. The pre-correction provisional detection value corresponds to the detection value before various corrections are made to the sensor signal. The processing performed by the codec 631 includes filtering, arctangent calculation processing, and the like. In arctangent calculation processing, arctangent (that is, arctangent) calculation is performed based on the sensor output of the first bridge circuit 21 corresponding to the sine wave and the sensor output of the second bridge circuit 22 corresponding to the cosine wave. processing.

The non-temporal correction unit 632 is provided to obtain a provisional detection value by performing non-temporal correction on the sensor signal. The non-temporal correction is correction caused by the characteristics of the magnetic detection element 20 and is different from the temporal correction. Temporal correction is correction due to temporal changes in sensor output, that is, correction for compensating for temporal changes.

The memory 64 stores various data necessary for the operation of the position detection device 1, such as initial values, tables, parameters, and the like. The arithmetic processing section 65 is provided so as to control each section of the detection value output section 6 . That is, the arithmetic processing unit 65 controls the interface 61 to alternately acquire the sensor output of the first bridge circuit 21 and the sensor output of the second bridge circuit 22 in a time division manner. Further, the arithmetic processing unit 65 controls operations of the temporal correction unit 66 and the selection unit 67 based on the temporary detection value acquired by the temporary detection value acquisition unit 63 and various data stored in the memory 64. It has become.

Specifically, the arithmetic processing unit 65 is provided so as to perform arithmetic processing based on the initial provisional detection value and the initial standard value to determine whether or not the provisional detection value needs to be corrected over time. The initial provisional detection value is a provisional detection value obtained by the provisional detection value obtaining section 63 corresponding to the initial position of the position detection target 3 . In this embodiment, the "initial position" is the position of the position detection target 3 when the ignition switch of the vehicle equipped with the position detection device 1 is turned on. The initial standard value is a value set in advance as a standard value of the detected value corresponding to the initial position and stored in the memory 64 in advance. Arithmetic processing based on the initial provisional detection value and the initial standard value is, for example, calculation of the difference between the two.

Further, the calculation processing unit 65 is provided so as to set parameters for correction over time based on the result of calculation processing when correction over time is required. That is, the arithmetic processing unit 65 reads parameters for temporal correction from the memory 64 based on the difference between the initial provisional detection value and the initial standard value and the table stored in the memory 64 .

When the arithmetic processing unit 65 determines that temporal correction is necessary, the temporal correction unit 66 corrects the temporary detection value over time based on the parameters set by the arithmetic processing unit 65, thereby correcting the detected value. It is designed to generate On the other hand, the detected value output unit 6 is configured to generate a detected value without executing the temporal correction by the temporal correction unit 66 when the arithmetic processing unit 65 determines that the temporal correction is unnecessary. .

Specifically, in this embodiment, a selection unit 67 is provided between the arithmetic processing unit 65 and the temporal correction unit 66 . The selection unit 67 inputs the output result of the temporary detection value acquiring unit 63 to the temporal correction unit 66 when the arithmetic processing unit 65 determines that temporal correction is necessary. The temporal correction unit 66 outputs the temporal correction result to the output terminal 68 . On the other hand, when the arithmetic processing unit 65 determines that the temporal correction is unnecessary, the selecting unit 67 outputs the output result of the temporary detection value acquisition unit 63 to the output terminal 68 without inputting it to the temporal correction unit 66. It's like

(effect)
The effects produced by the configuration of the present embodiment will be described below together with an outline of the operation of the configuration.

In the above configuration, the sensor element section 2 outputs a sensor signal corresponding to the position of the position detection target 3 . The temporary detection value acquisition unit 63 acquires a temporary detection value corresponding to the temporary detection result of the position of the position detection target 3 by processing the sensor signal. The detection value output unit 6 outputs a detection value corresponding to the detection result of the position of the position detection target 3 based on the sensor signal, that is, the provisional detection value.

In the graph of FIG. 3, the horizontal axis P represents the position of the position detection target 3, and the vertical axis V represents the output of the provisional detection value acquisition unit 63. The graph of FIG. The vertical axis V in FIG. 3 corresponds to voltage.

As indicated by the dashed line in FIG. 3, the ideal correspondence relationship between the position and the output voltage is a substantially linear relationship. However, in reality, as indicated by the solid line in FIG. 3, errors from the ideal linear relationship occur due to temporal or non-temporal factors. Such an error increases over time as indicated by the dashed line in FIG. If, as indicated by the chain double-dashed line in FIG. 3, a standard is set in consideration of endurance fluctuations, it would be difficult to improve the accuracy of position detection.

In this respect, the initial position of the position detection target 3 may be estimated with high probability. Specifically, for example, in the present embodiment, the position detection device 1 is an in-vehicle shift position detection device. In this case, the initial position is most likely in the "P" range.

Therefore, the calculation processing unit 65 performs calculation processing based on the initial provisional detection value and the initial standard value, thereby determining whether or not the provisional detection value needs to be corrected over time. The initial provisional detection value is a provisional detection value obtained by the provisional detection value obtaining section 63 corresponding to the initial position of the position detection target 3 . The initial standard value is a value set in advance as a standard value of the detected value corresponding to the initial position.

When the arithmetic processing unit 65 determines that the temporary detection value needs to be corrected with time, the temporal correction unit 66 performs temporal correction on the temporary detection value to generate a detection value. On the other hand, when the arithmetic processing unit 65 determines that temporal correction of the provisional detection value is unnecessary, the detection value is generated without performing temporal correction of the provisional detection value.

FIG. 4 shows an outline of the operation of the detection value output section 6 shown in FIG. In addition, in the flowchart of FIG. 4, "S" is an abbreviation for "step".

The routine shown in FIG. 4 is started when the ignition switch of the vehicle is turned on. When this routine starts, first, in step 401, the AD converter 62 acquires a sensor signal corresponding to the initial position of the position detection target 3. FIG.

Next, in step 402, the codec 631 acquires a pre-correction provisional detection value corresponding to the initial position of the position detection target 3 by processing the acquired sensor signal. Also, the non-temporal correction unit 632 performs non-temporal correction on the output of the codec 631 to obtain an initial provisional detection value.

Subsequently, at step 403 , the arithmetic processing unit 65 reads out the initial standard value from the memory 64 to obtain the initial standard value. Further, at step 404, the arithmetic processing unit 65 performs a comparison operation between the initial provisional detection value and the initial standard value. Specifically, the arithmetic processing unit 65 calculates the difference Δd between the initial provisional detection value and the initial standard value. Processing then proceeds to step 405 .

At step 405, the arithmetic processing unit 65 determines whether or not Δd is between predetermined standard values Δd1 and Δd2. If Δd1≦Δd≦Δd2 (ie, step 405=YES), processing proceeds to step 406; That is, the arithmetic processing unit 65 determines that the temporal correction is unnecessary. On the other hand, if Δd is not between the predetermined standard values Δd1 and Δd2 (that is, step 405=NO), the process proceeds to step 407. That is, the arithmetic processing unit 65 determines that temporal correction is necessary.

If temporal correction is required (that is, step 407), the arithmetic processing unit 65 reads correction parameters α, β, γ in the following correction formula from the memory 64 based on the value of Δd. In addition, in the following correction formula, x is a provisional detection value. Also, the table stored in the memory 64 that defines the relationship between Δd and the correction parameters α, β, γ can be obtained through experiments and/or computer simulations.
f(x)=α·x ² +β·x+γ

If temporal correction is required (ie step 407 ), then processing proceeds to step 408 . At step 408 , the temporal correction unit 66 performs temporal correction on the provisional detection values based on the correction parameters α, β, and γ set by the arithmetic processing unit 65 to generate detection values.

If no temporal correction is required (ie, step 405=YES), processing proceeds from step 406 to step 409; At step 409 , the detected value output unit 6 outputs the output of the temporary detected value acquisition unit 63 to the output terminal 68 . In other words, the detection value output unit 6 outputs the initial provisional detection value as the initial value of the detection value without executing correction over time.

On the other hand, if a correction over time is required (ie, step 405=NO), processing proceeds from step 407 through step 408 to step 409 . At step 409 , the detection value output section 6 outputs the output of the temporal correction section 66 to the output terminal 68 . In other words, the detection value output unit 6 outputs the result of performing temporal correction on the initial provisional detection value, which is the output of the provisional detection value acquisition unit 63, as the initial value of the detection value.

According to the above configuration, the initial provisional detection value, which is the provisional detection value acquired by the provisional detection value acquiring unit 63 corresponding to the initial position of the position detection target 3, and the detection value corresponding to the initial position of the position detection target 3 Based on the initial standard value set in advance as the standard value of , it is possible to satisfactorily determine whether or not correction over time is necessary. Therefore, it is possible to satisfactorily suppress changes in detection results over time, that is, variations in endurance.

(Modification)
The present invention is not limited to the above embodiments. Therefore, the above embodiment can be modified as appropriate. A representative modified example will be described below. In the following description of the modified example, only parts different from the above embodiment will be described. Moreover, in the above-described embodiment and modifications, the same reference numerals are given to parts that are the same or equivalent to each other. Therefore, in the description of the modification below, the description in the above embodiment can be used as appropriate for components having the same reference numerals as those in the above embodiment, unless there is a technical contradiction or special additional description.

The present invention is not limited to the specific device configurations shown in the above embodiments. For example, the position detection device 1 is not limited to a shift position detection device. That is, for example, the position detection device 1 may be a rotational position detection device for the position detection target 3, which is a rotating body.

The configuration of the sensor element section 2 is not particularly limited as long as the problems of the present invention are satisfactorily solved and the effects are exhibited satisfactorily. Specifically, for example, the magnetic detection element 20 may be a so-called GMR element. GMR is an abbreviation for Giant Magneto Resistance. Further, the sensor element section 2 is not limited to a configuration in which a plurality of magnetic detection elements 20 are bridge-connected.

The detected value output section 6 may have a logic configuration including an ASIC. ASIC is an abbreviation for Application Specific Integrated Circuit. Alternatively, the detected value output section 6 may be configured as an in-vehicle microcomputer including a CPU, a ROM, a RAM, a nonvolatile RAM, and the like. Non-volatile RAM is, for example, flash ROM or the like.

In the present invention, the non-temporal correction unit 632 is not essential. That is, the non-temporal correction unit 632 can be omitted. Alternatively, the temporal correction unit 66 may be configured to perform both temporal correction and non-temporal correction.

The temporal correction unit 66 and the selection unit 67 can be configured as integrated processing or logic.

The present invention is not limited to the specific processing modes shown in the above embodiments. For example, at step 404, the arithmetic processing unit 65 may calculate the ratio between the initial provisional detection value and the initial standard value.

If the position detection device 1 is a shift position detection device mounted on a manual transmission vehicle, the initial position and the initial standard value may correspond to the neutral position.

As described above, the present invention can be preferably applied to a system configuration in which the position is uniquely determined at startup, such as when the position detection device 1 is a shift position detection device. However, the present invention is not limited to such system configurations.

That is, for example, the initial position can be obtained by storing in the memory 64 the position of the position detection target 3 at the time of the previous system shutdown. In this case, the initial standard value may be a standard value corresponding to the initial position read out from the memory 64 at the time of system startup.

Needless to say, the elements constituting the above-described embodiments are not necessarily essential, unless explicitly stated as essential or clearly considered essential in principle. In addition, when numerical values such as the number, numerical value, amount, range, etc. of a constituent element are mentioned, unless it is explicitly stated that it is particularly essential or when it is clearly limited to a specific number in principle, The present invention is not limited to the number of .

Similarly, when the shape, direction, positional relationship, etc. of the constituent elements, etc. are mentioned, unless it is explicitly stated that it is particularly essential, or when it is limited to a specific shape, direction, positional relationship, etc. in principle , the shape, direction, positional relationship, etc., of which the present invention is not limited. There are no particular limitations on the materials that constitute each part, except when it is explicitly stated that they are particularly essential or when they are clearly limited to specific materials in principle.

Modifications are also not limited to the above examples. Also, multiple embodiments may be combined with each other. Likewise, multiple variants can be combined with each other. Furthermore, at least one of the multiple embodiments and at least one of the multiple variations may be combined with each other.

Reference Signs List 1 position detection device 2 sensor element section 3 position detection target 20 magnetic detection element 21 first bridge circuit 22 second bridge circuit 6 detection value output section 63 provisional detection value acquisition section 65 arithmetic processing section 66 temporal correction section

Claims (4)

A position detection device (1) configured to detect the position of a position detection target (3),
a sensor element unit (2) configured to output a sensor signal, which is an electrical signal corresponding to the position;
a detection value output unit (6) configured to output a detection value corresponding to the detection result of the position based on the sensor signal;
with
The detected value output unit is
a provisional detection value acquiring unit (63) provided to acquire a provisional detection value corresponding to the provisional detection result of the position by processing the sensor signal;
An initial provisional detection value, which is the provisional detection value acquired by the provisional detection value acquisition unit, corresponding to the initial position, which is the position at the time of system startup of the position detection target, and the detection value corresponding to the initial position. A calculation processing unit (65) provided to determine whether or not to correct the provisional detection value over time by performing calculation processing based on an initial standard value preset as a standard value of
provided to generate the detection value by performing the temporal correction on the provisional detection value when the arithmetic processing unit determines that the provisional detection value needs to be corrected with time; a correction unit (66);
with
The provisional detection value obtaining unit performs non-temporal correction, which is different from the temporal correction, on the pre-correction provisional detection value obtained by processing the sensor signal, so that the temporal correction is configured to obtain the tentative detection value that is not
Position detection device. The arithmetic processing unit is configured to set parameters for the temporal correction based on the result of the arithmetic processing.
The position detection device according to claim 1. The sensor element unit has a configuration in which a plurality of magnetic detection elements (20) are bridge-connected,
The position detection device according to claim 1 or 2. The position detection target is provided so as to move relative to the magnetic detection element in accordance with the operation state of a gearshift shift lever (4) provided in the vehicle,
The position detection device according to claim 3.

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