JP2019200149A - Position detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To satisfactorily suppress changes in detection results over time, that is, variations in durability. A position detection device (1) includes a sensor element section (2) and a detection value output section (6). The sensor element unit outputs a sensor signal corresponding to the position of the position detection target (3). The detection value output unit includes a temporary detection value acquisition unit (63), a calculation processing unit (65), and a time correction unit (66). The temporary detection value acquisition unit acquires the temporary detection value corresponding to the temporary detection result of the position by processing the sensor signal. The arithmetic processing unit performs temporary detection based on an initial temporary detection value that is a temporary detection value corresponding to the initial position of the position detection target and an initial standard value preset as a standard value of the detection value corresponding to the initial position. It is determined whether or not the value needs to be corrected over time. The temporal correction unit generates a detected value by performing temporal correction on the temporary detection value when the arithmetic processing unit determines that temporal correction on the temporary detection value is necessary. [Selection diagram] Figure 2

Description

  The present invention relates to a position detection device.

  As this type of apparatus, for example, the apparatus described in Patent Document 1 is known. In the apparatus described in Patent Document 1, a magnetic sensor for detecting a change in a magnetic field accompanying the movement of a magnet is provided. This apparatus 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 apparatus, the detection result can change with time, that is, endurance fluctuation. In general, a reference value is required to control the endurance fluctuation. However, for example, in a position detection device mounted on a vehicle, the output itself of the sensor element used is a reference for the physical quantity used for position detection. For this reason, it was difficult to control the endurance fluctuation.

  The present invention has been made in view of the circumstances exemplified above. That is, an object of the present invention is to satisfactorily suppress a change in detection result with time, that is, a variation in durability.

The position detection device (1) according to claim 1 is configured to detect the position of the position detection target (3).
This position detection device
A sensor element portion (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
A temporary detection value acquisition unit (63) provided to acquire a temporary detection value corresponding to the temporary detection result of the position by processing the sensor signal;
An initial temporary detection value that is the temporary detection value acquired by the temporary detection value acquisition unit corresponding to the initial position of the position detection target and a standard value of the detection value corresponding to the initial position are set in advance. An arithmetic processing unit (65) provided to determine whether or not the temporal detection correction is necessary for the temporary detection value by performing arithmetic processing based on the initial standard value;
Temporal correction provided to generate the detection value by executing the temporal correction on the temporary detection value when the arithmetic processing unit determines that the temporal correction on the temporary detection value is necessary Part (66);
It has.

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

  The initial position of the position detection target may be estimated with high probability. Specifically, for example, when the position detection device is a so-called shift position detection device mounted on a vehicle, the initial position has a high probability and is in the “P” range.

  Therefore, the arithmetic processing unit determines whether or not the temporal correction is necessary for the temporary detection value by performing arithmetic processing based on the initial temporary detection value and the initial standard value. The initial temporary detection value is the temporary detection value acquired by the temporary detection value acquisition unit corresponding to the initial position of the position detection target. The initial standard value is a value set in advance as a standard value of the detection value corresponding to the initial position.

  The time correction unit generates the detection value by executing the time correction on the temporary detection value when the arithmetic processing unit determines that the time correction on the temporary detection value is necessary. . On the other hand, when the arithmetic processing unit determines that the temporal correction for the temporary detection value is unnecessary, the detection value is generated without executing the temporal correction for the temporary detection value.

  According to the above configuration, the initial temporary detection value that is the temporary detection value acquired by the temporary detection value acquisition unit corresponding to the initial position of the position detection target, and the initial position of the position detection target. Based on the initial standard value set in advance as the standard value of the corresponding detection value, it is possible to satisfactorily determine whether the temporal correction is necessary. Therefore, it is possible to satisfactorily suppress the change with time of the detection result, that is, the durability fluctuation.

  In each column of the application document, when each element is given a reference numeral in parentheses, the reference numeral simply indicates a correspondence relationship between the element and a specific configuration described in an embodiment described later. An example is shown. Therefore, the present invention is not limited by the description of the reference symbols.

It is a schematic diagram which shows schematic structure of the position detection apparatus which concerns on embodiment. It is a block diagram which shows schematic structure of the position detection apparatus shown by FIG. It is a graph which shows the operation | movement outline | summary of the position detection apparatus shown by FIG. It is a flowchart which shows the operation | movement outline | summary of the position detection apparatus shown by FIG.

(Embodiment)
Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that various modifications that can be applied to one embodiment may interfere with understanding of the embodiment if inserted in the middle of a series of descriptions related to the embodiment. It is described collectively after the explanation.

(Constitution)
First, a schematic configuration of the position detection device 1 according to the embodiment will be described with reference to FIG. For convenience of explanation, in FIG. 1, right-handed XYZ orthogonal coordinates are set as shown. The position detection device 1 according to the present embodiment is configured to detect the relative positions of the sensor element unit 2 and the position detection target 3 in the X-axis direction in the figure. For simplification of description, 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 “position of the position detection target 3”. The position detection target 3 is provided with a movable magnet.

  In the present 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 target 3 is coupled to a shift lever 4 for shifting provided in the vehicle via a coupling mechanism 5. The position detection target 3 is provided so as to move relative to the sensor element unit 2 in the X-axis direction in the figure in accordance with the operation state of the shift lever 4.

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

  Referring to FIG. 2, the sensor element unit 2 has a configuration in which a plurality of magnetic detection elements 20 are bridge-connected. Specifically, the sensor element unit 2 includes 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 including a plurality of magnetic detection elements 20 and are configured to output a sensor signal that is an electrical signal corresponding to the position of the position detection target 3. Yes. The first bridge circuit 21 is provided so as to generate a sinusoidal output when the position detection target 3 continuously moves at a constant speed in the X-axis direction in the figure. The second bridge circuit 22 is provided so as to generate a cosine wave-like output when the position detection target 3 continuously moves at a constant speed in the X-axis direction in the figure.

  Referring to FIG. 2, the position detection device 1 further includes a detection value output unit 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. Yes. Specifically, in the present embodiment, the detection value output unit 6 includes an interface 61, an AD converter 62, a provisional detection value acquisition unit 63, a memory 64, an arithmetic processing unit 65, and a temporal correction unit 66. , A selection unit 67 and an output terminal 68 are provided.

  The first bridge circuit 21 and the second bridge circuit 22 are electrically connected to the interface 61 in parallel. The interface 61 is provided so that the sensor output of the first bridge circuit 21 and the sensor output of the second bridge circuit 22 are alternately obtained by time division and input to the AD converter 62. The AD converter 62 is provided to perform analog / digital conversion on the input sensor output and input the conversion result to the provisional detection value acquisition unit 63.

  The temporary detection value acquisition unit 63 acquires the temporary detection value corresponding to the temporary 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 provided to do. Specifically, the provisional detection value acquisition unit 63 includes a codec 631 and a non-aging correction unit 632.

  The codec 631 is provided so as to acquire the pre-correction provisional detection value by processing the sensor signal analog / digital converted by the AD converter 62. The pre-correction provisional detection value corresponds to a detection value before various corrections are performed on the sensor signal. The processing executed by the codec 631 includes filter processing, arc tangent calculation processing, and the like. In the arc tangent calculation processing, arc tangent (that is, arctangent) calculation is executed 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. It is processing.

  The non-aging correction unit 632 is provided so as to acquire a provisional detection value by performing non-aging correction on the sensor signal. Non-temporal correction is correction due to the characteristics of the magnetic detection element 20 and is different from the temporal correction. The time correction is a correction caused by a change in sensor output with time, that is, a correction for compensating for a change with time.

  The memory 64 stores various data necessary for the operation of the position detection apparatus 1, for example, initial values, tables, parameters, and the like. The arithmetic processing unit 65 is provided to control each unit of the detection value output unit 6. In other words, the arithmetic processing unit 65 controls the interface 61 to acquire the sensor output of the first bridge circuit 21 and the sensor output of the second bridge circuit 22 alternately in a time division manner. The arithmetic processing unit 65 controls the 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 determine whether or not correction with time is necessary for the temporary detection value by performing arithmetic processing based on the initial temporary detection value and the initial standard value. The initial temporary detection value is a temporary detection value acquired by the temporary detection value acquisition unit 63 corresponding to the initial position of the position detection target 3. In the present embodiment, the “initial position” is the position of the position detection target 3 at the time when the ignition switch of the vehicle on which the position detection device 1 is mounted is turned on. The initial standard value is a value set in advance as the standard value of the detection value corresponding to the initial position, and is stored in the memory 64 in advance. The arithmetic processing based on the initial temporary detection value and the initial standard value is, for example, calculation of the difference between the two.

  In addition, the arithmetic processing unit 65 is provided so as to set a parameter for temporal correction when temporal correction is necessary based on the result of the arithmetic processing. That is, the arithmetic processing unit 65 reads out the time correction parameter 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 the temporal correction is necessary, the temporal correction unit 66 performs temporal correction on the temporary detection value based on the parameter set by the arithmetic processing unit 65, thereby obtaining the detected value. It is provided to generate. On the other hand, the detection value output unit 6 is configured to generate a detection value without performing the temporal correction by the temporal correction unit 66 when the arithmetic processing unit 65 determines that the temporal correction is unnecessary. .

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

(effect)
Hereinafter, the effect produced by the configuration of the present embodiment will be described together with the operation outline of the configuration.

  In the above configuration, the sensor element unit 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 temporary detection value.

  The graph of FIG. 3 shows the correspondence between the position detection target 3 on the horizontal axis P and the output of the provisional detection value acquisition unit 63 on the vertical axis V. The vertical axis V in FIG. 3 corresponds to voltage.

  As indicated by the alternate long and short dash line in FIG. 3, the ideal correspondence between the position and the output voltage is almost linear. However, in practice, as indicated by a solid line in FIG. 3, an error from an ideal linear relationship occurs due to factors with time or non-time. Such error increases with time as shown by the broken line in FIG. As shown by a two-dot chain line in FIG. 3, if a standard that allows for endurance variation is provided, it is difficult to improve the accuracy of position detection.

  In this regard, 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 on-vehicle shift position detection device. In this case, the initial position is “P” range with high probability.

  Therefore, the arithmetic processing unit 65 performs arithmetic processing based on the initial temporary detection value and the initial standard value to determine whether or not the temporal detection correction is necessary for the temporary detection value. The initial temporary detection value is a temporary detection value acquired by the temporary detection value acquisition unit 63 corresponding to the initial position of the position detection target 3. The initial standard value is a value preset as a standard value of the detection value corresponding to the initial position.

  The temporal correction unit 66 generates a detection value by executing temporal correction on the temporary detection value when the arithmetic processing unit 65 determines that the temporal correction on the temporary detection value is necessary. On the other hand, when the arithmetic processing unit 65 determines that the temporal correction for the temporary detection value is unnecessary, the detection value is generated without executing the temporal correction for the temporary detection value.

  FIG. 4 shows an outline of the operation of the detection value output unit 6 shown in FIG. 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.

  Next, in step 402, the codec 631 processes the acquired sensor signal to acquire a pre-correction temporary detection value corresponding to the initial position of the position detection target 3. Further, the non-aging correction unit 632 obtains an initial provisional detection value by performing non-aging correction on the output of the codec 631.

  Subsequently, in step 403, the arithmetic processing unit 65 reads the initial standard value from the memory 64 to acquire the initial standard value. Furthermore, in step 404, the arithmetic processing unit 65 compares the initial temporary detection value with the initial standard value. Specifically, the arithmetic processing unit 65 calculates a difference Δd between the initial temporary detection value and the initial standard value. Thereafter, the process proceeds to step 405.

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

When time correction is necessary (ie, step 407), the arithmetic processing unit 65 reads out the correction parameters α, β, γ in the following correction formula from the memory 64 based on the value of Δd. In the correction formula below, x is a provisional detection value. The table stored in the memory 64 that defines the relationship between Δd and the correction parameters α, β, γ can be obtained by experiments and / or computer simulations.
f (x) = α · x ² + β · x + γ

  If time correction is required (ie, step 407), then processing proceeds to step 408. In step 408, the temporal correction unit 66 generates a detection value by executing temporal correction on the provisional detection value based on the correction parameters α, β, and γ set by the arithmetic processing unit 65.

  If time correction is not necessary (ie, step 405 = YES), the process proceeds from step 406 to step 409. In step 409, the detection value output unit 6 outputs the output of the temporary detection value acquisition unit 63 to the output terminal 68. That is, the detection value output unit 6 outputs the initial temporary detection value as the initial value of the detection value without executing the temporal correction.

  On the other hand, when time correction is necessary (ie, step 405 = NO), the process proceeds from step 407 to step 409 through step 408. In step 409, the detection value output unit 6 outputs the output of the time correction unit 66 to the output terminal 68. That is, the detection value output unit 6 outputs the result of performing the temporal correction on the initial temporary detection value that is the output of the temporary detection value acquisition unit 63 as the initial value of the detection value.

  According to the above configuration, the initial temporary detection value that is the temporary detection value acquired by the temporary detection value acquisition 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, it is possible to satisfactorily determine whether or not the temporal correction is necessary. Therefore, it is possible to satisfactorily suppress the change with time of the detection result, that is, the durability fluctuation.

(Modification)
The present invention is not limited to the above embodiment. Therefore, it can change suitably with respect to the said embodiment. Hereinafter, typical modifications will be described. In the following description of the modified example, only the parts different from the above embodiment will be described. Moreover, in the said embodiment and a modification, the same code | symbol is attached | subjected to the part which is mutually the same or equivalent. Therefore, in the following description of the modified example, regarding the components having the same reference numerals as those in the above embodiment, the description in the above embodiment can be appropriately incorporated unless there is a technical contradiction or special additional explanation.

  The present invention is not limited to the specific apparatus configuration shown in the above embodiment. For example, the position detection device 1 is not limited to the shift position detection device. That is, for example, the position detection device 1 may be a rotation position detection device of the position detection target 3 that is a rotating body.

  The configuration of the sensor element unit 2 is not particularly limited as long as the problems of the present invention are solved satisfactorily and the effects are excellent. 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 unit 2 is not limited to a configuration in which a plurality of magnetic detection elements 20 are bridge-connected.

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

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

  The time correction unit 66 and the selection unit 67 can be configured as an integrated process or logic.

  The present invention is not limited to the specific processing mode shown in the above embodiment. For example, in step 404, the arithmetic processing unit 65 may calculate a ratio between the initial temporary detection value and the initial standard value.

  When 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 suitably applied in a system configuration in which the position is uniquely determined at the time of activation, such as when the position detection device 1 is a shift position detection device. However, the present invention is not limited to such a system configuration.

  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 previous system shutdown. In this case, the initial standard value may be a standard value corresponding to the initial position read from the memory 64 when the system is started this time.

  It goes without saying that the elements constituting the above-described embodiment are not necessarily essential except for the case where it is clearly indicated that it is essential and the case where it is considered that it is clearly essential in principle. In addition, when numerical values such as the number, numerical value, quantity, range, etc. of a component are mentioned, the specifics are specified unless explicitly stated as being essential and when clearly limited to a specific number in principle. The present invention is not limited to this number.

  Similarly, when the shape, direction, positional relationship, etc. of a component is mentioned, except when clearly stated as being essential, and in principle limited to a specific shape, direction, positional relationship, etc. The present invention is not limited to the shape, direction, positional relationship, and the like. The material constituting each part is not particularly limited unless it is specified as being particularly essential, or is clearly limited to a specific material in principle.

  The modification is not limited to the above example. Also, multiple embodiments can be combined with each other. Similarly, multiple variations can be combined with each other. Furthermore, at least one of the plurality of embodiments and at least one of the plurality of modifications may be combined with each other.

DESCRIPTION OF SYMBOLS 1 Position detection apparatus 2 Sensor element part 3 Position detection object 20 Magnetic detection element 21 1st bridge circuit 22 2nd bridge circuit 6 Detection value output part 63 Temporary detection value acquisition part 65 Operation processing part 66 Time correction part

Claims (5)

A position detection device (1) configured to detect a position of a position detection target (3),
A sensor element portion (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
A temporary detection value acquisition unit (63) provided to acquire a temporary detection value corresponding to the temporary detection result of the position by processing the sensor signal;
An initial temporary detection value that is the temporary detection value acquired by the temporary detection value acquisition unit corresponding to the initial position of the position detection target and a standard value of the detection value corresponding to the initial position are set in advance. An arithmetic processing unit (65) provided to determine whether or not the temporal detection correction is necessary for the temporary detection value by performing arithmetic processing based on the initial standard value;
When the arithmetic processing unit determines that the temporal correction for the temporary detection value is necessary, the temporal processing is provided to generate the detection value by executing the temporal correction for the temporary detection value. A correction unit (66);
A position detection device comprising: The temporary detection value acquisition unit executes the non-temporal correction, which is a correction different from the temporal correction, on the pre-correction temporary detection value acquired by processing the sensor signal. Configured to get the
The position detection device according to claim 1. The arithmetic processing unit is configured to set the time correction parameter based on the result of the arithmetic processing.
The position detection device according to claim 1 or 2. 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. The position detection target is provided so as to move relative to the magnetic detection element in response to an operation state of a shift lever (4) for shifting provided in the vehicle.
The position detection device according to claim 4.

Images