JP6497376B2 - Sensor signal value storage device - Google Patents

Description

  The technology disclosed herein relates to a sensor signal value storage device that stores a signal value output from a sensor.

  In a vehicle development site, many sensors may be attached to various parts of the vehicle (see Patent Document 1). Since the sensor of Patent Document 1 is connected to the data collection device by a signal line, an operator needs to spend a great deal of labor for arranging the signal line between the sensor and the data collection device.

  Patent Document 2 proposes a technique for wirelessly communicating data acquired by a sensor to a data collection device. According to the technique of Patent Document 2, the operation of arranging the signal line between the sensor and the data collection device is not required.

JP2013-253898A JP 2008-164467 A

  Whether the data is communicated in a wired manner or wirelessly, it is desirable that the data acquired by the sensor be obtained with high accuracy. For example, a corrosion sensor that detects the degree of corrosion at the mounting location may be attached to the vehicle as a sensor. The corrosion sensor generally outputs a current value corresponding to the degree of corrosion. However, since the current value is very small, the current value is usually amplified and recorded. However, since the corrosion sensor may be attached outside the vehicle, it is desired that the corrosion sensor is not affected by temperature. However, Patent Documents 1 and 2 do not fully examine this point.

  An object of the technology disclosed herein is to provide a sensor signal value storage device in which a signal value of a sensor is hardly affected by temperature.

In order to solve the above-described problem, one aspect of the technology disclosed herein is as follows:
A state detector that outputs a current value representing a state of a predetermined mounting location as an output current value;
A temperature detector for detecting the ambient temperature of the state detector;
A storage unit;
A storage control unit that stores the state of the mounting location in the storage unit;
With
The state detection unit is configured such that a range of the output current value is a range from a predetermined minimum current value to a predetermined maximum current value, and includes the first current value. A first mode for outputting the output current value as a current range and a second mode for outputting the output current value as a second current range not including the minimum current value;
In the first mode, the storage control unit stores a correction value obtained by correcting the output value corresponding to the output current value based on the temperature detected by the temperature detection unit in the storage unit, and the second mode. In the mode, the output value is stored in the storage unit.

  In this aspect, the state detection unit that outputs the current value representing the state of the mounting location as the output current value has a range of the output current value ranging from a predetermined minimum current value to a predetermined maximum current value. It is comprised so that it may become. In addition, the state detection unit includes a first mode that outputs an output current value as a first current range that includes a minimum current value, and a second mode that outputs an output current value as a second current range that does not include the minimum current value; Have

  In the first mode, a correction value obtained by correcting the output value corresponding to the output current value based on the temperature detected by the temperature detection unit is stored in the storage unit. In the second mode, the output value corresponding to the output current value is stored in the storage unit.

  When the output current value is output from the state detection unit as the first current range including the minimum current value, the output current value is very small and thus is affected by temperature. Therefore, in the first mode, a correction value obtained by correcting the output value corresponding to the output current value based on the temperature detected by the temperature detection unit is stored in the storage unit. Therefore, according to this aspect, it is possible to eliminate the influence of temperature and store the value that accurately represents the state of the mounting location in the storage unit.

  In the above aspect, for example, in the first mode, the storage control unit stores the correction value in the storage unit only when the temperature detected by the temperature detection unit is equal to or higher than a predetermined temperature threshold, When the temperature detected by the temperature detection unit is lower than the temperature threshold, the output value may be stored in the storage unit.

  In this aspect, in the first mode, the correction value is stored in the storage unit only when the temperature detected by the temperature detection unit is equal to or higher than a predetermined temperature threshold, and the temperature detected by the temperature detection unit is less than the temperature threshold. Sometimes the output value is stored in the storage unit. When the output current value is output from the state detection unit as the first current range including the minimum current value, the temperature is more greatly affected when the detected temperature is equal to or higher than the temperature threshold compared to when the detected temperature is lower than the temperature threshold. Therefore, according to this aspect, when the detected temperature is equal to or higher than the temperature threshold, the influence of the temperature can be eliminated, and a value that accurately represents the state of the mounting location can be stored in the storage unit.

  In the above aspect, for example, the minimum current value may be 0.01 nA. The first current range may be 0.01 nA or more and 0.03 μA or less.

  When it is within the range of 0.01 nA or more and 0.03 μA or less, the output current value is very small and is greatly affected by temperature. Therefore, a correction value obtained by correcting the output value corresponding to the output current value based on the temperature detected by the temperature detection unit is stored in the storage unit. Therefore, according to this aspect, it is possible to eliminate the influence of temperature and store the value that accurately represents the state of the mounting location in the storage unit.

  In the above aspect, for example, the state detection unit may include a corrosion sensor that outputs a current value corresponding to the degree of corrosion at the mounting location as the output current value.

  In this aspect, the state detection unit includes a corrosion sensor that outputs a current value corresponding to the degree of corrosion at the mounting location as an output current value. When the current value output from the corrosion sensor according to the degree of corrosion at the installation location is very small, it is greatly affected by temperature. Therefore, when the output current value is very small, a correction value obtained by correcting the output value corresponding to the output current value based on the temperature detected by the temperature detection unit is stored in the storage unit. Therefore, according to this aspect, it is possible to eliminate the influence of the temperature and store the value that accurately represents the degree of corrosion at the mounting location in the storage unit.

  In the above aspect, for example, the storage control unit is wired to the state detection unit and the temperature detection unit, generates the correction value from the output current value in the first mode, and outputs the correction value in the first mode. A correction unit that generates the output value from a current value, a first antenna unit for wirelessly transmitting the correction value or the output value, and wireless transmission of the correction value or the output value from the first antenna unit. A first communication control unit to control; a second antenna unit for receiving the correction value or the output value transmitted from the first antenna unit; and the correction value received by the second antenna unit or the A second communication control unit that stores the output value in the storage unit.

  In this aspect, the correction value or the output value is transmitted from the first antenna unit and received by the second antenna unit. Therefore, according to this aspect, since the correction value or the output value is transmitted wirelessly, there is an advantage that it is not necessary to consider the routing of the wiring between the state detection unit and the storage unit.

  In the above aspect, for example, the state detection unit, the temperature detection unit, the storage unit, and the storage control unit may be mounted on a vehicle.

  In this aspect, the state detection unit, the temperature detection unit, the storage unit, and the storage control unit are mounted on the vehicle. Therefore, according to this aspect, the state of the mounting location in the vehicle can be examined.

  In the above aspect, for example, the state detection unit may be attached to the outside of the vehicle.

  In this aspect, the state detection unit is attached outside the vehicle. Therefore, according to this aspect, the state of the outdoor installation location in the vehicle can be examined.

  According to the sensor signal value storage device, in the first mode in which the output current value is output from the state detection unit as the first current range including the minimum current value, the output value corresponding to the output current value is detected by the temperature detection unit. Since the correction value corrected based on the set temperature is stored in the storage unit, the influence of the temperature can be eliminated, and a value that accurately represents the state of the mounting location can be stored in the storage unit.

It is a block diagram showing roughly the composition of vehicles provided with the sensor signal value storage device of this embodiment. It is a figure which shows roughly the example of arrangement | positioning of a radio | wireless transmitter, a detection part, a data collection device, and an antenna unit. It is a figure which shows roughly the change with respect to the temperature of the voltage amplification value output from an amplifier circuit.

  Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each figure, the same numerals are given to the same element, and explanation is omitted suitably.

  FIG. 1 is a block diagram schematically showing a configuration of a vehicle including a sensor signal value storage device of the present embodiment. A vehicle 1 shown in FIG. 1 is, for example, a four-wheeled vehicle. As shown in FIG. 1, the vehicle 1 includes a wireless transmission device 10, a detection unit 20, a data collection device 30, and an antenna unit 40.

  The vehicle 1 is used for evaluating the performance of a vehicle using a large number of sensors attached to the vehicle at a vehicle development site. In the present embodiment, the detection unit 20 includes a corrosion sensor 21 and a temperature / humidity sensor 22 as such sensors. The corrosion sensor 21 is connected to the wireless transmission device 10 via a connection cable 23, and the temperature / humidity sensor 22 is connected to the wireless transmission device 10 via a connection cable 24. The antenna unit 40 is connected to the data collection device 30 by a connection cable 41. The vehicle 1 is configured such that the detection data detected by the detection unit 20 is transmitted wirelessly by the wireless transmission device 10 and stored in the data collection device 30 via the antenna unit 40.

  The corrosion sensor 21 (an example of a state detection unit) detects the degree of corrosion in the vehicle 1 where the corrosion sensor 21 is attached. The corrosion sensor 21 may be a general sensor element that can detect the degree of corrosion of the vehicle 1. As the corrosion sensor 21, for example, an atmospheric corrosion monitor (ACM) type corrosion sensor may be used.

  The temperature / humidity sensor 22 (an example of a temperature detection unit) detects the temperature and humidity of the vehicle 1 where the temperature / humidity sensor 22 is attached. A general detection element may be used as the temperature / humidity sensor 22. As a temperature detection element of the temperature / humidity sensor 22, for example, a known platinum resistance thermometer may be used. As a humidity detection element of the temperature / humidity sensor 22, for example, a known polymer capacitive humidity detection element may be used.

  FIG. 2 is a diagram schematically illustrating an arrangement example of the wireless transmission device 10, the detection unit 20, the data collection device 30, and the antenna unit 40.

  The detection unit 20 is attached to four locations of the vehicle 1 such as an engine room, a front wheel house, a lift gate outer plate, and an engine under cover. The wireless transmission device 10 connected to the detection unit 20 with connection cables 23 and 24 is attached to four locations of the vehicle 1 in the vicinity of the detection unit 20. The data collection device 30 is disposed, for example, in the trunk room 2 of the vehicle 1. The antenna unit 40 is disposed, for example, on the ceiling of the indoor front portion 3 of the vehicle 1.

  Returning to FIG. 1, the wireless transmission device 10 includes a memory 11, a central processing unit (CPU) 12, an antenna unit 13, an amplifier circuit 15, a correction circuit 16, an AD conversion circuit 17, and the like.

  The memory 11 of the wireless transmission device 10 is configured by, for example, a semiconductor memory such as a flash memory, or another storage element. The memory 11 includes a memory that temporarily stores detection data detected by the detection unit 20, a memory that stores a program, and the like. Note that the memory 11 may be configured by a single memory element including an area for temporarily storing detection data detected by the detection unit 20 and an area for storing a program.

  As described above, the detection unit 20 and the wireless transmission device 10 are attached to a plurality of locations (four locations in the present embodiment) of the vehicle 1. Therefore, the memory 11 of the four wireless transmission devices 10 stores in advance unique child device IDs that identify the respective wireless transmission devices 10.

  In this embodiment, the antenna unit 13 (an example of a first antenna unit) radiates a radio wave with a frequency of 2.4 GHz with a power of 3 mW, for example. The corrosion sensor 21 is connected to the amplifier circuit 15 by a connection cable 23. The temperature / humidity sensor 22 is connected to the correction circuit 16 and the CPU 12 by a connection cable 24. The CPU 12 functions as a detection control unit 12a and a communication control unit 12b by operating according to a program stored in the memory 11.

  The corrosion sensor 21 outputs a current value corresponding to the degree of corrosion at the mounting location of the corrosion sensor 21. The amplification circuit 15 converts the current value output from the corrosion sensor 21 into a voltage value, amplifies the voltage value, and outputs a voltage amplification value. The correction circuit 16 outputs a voltage correction value obtained by correcting the voltage amplification value output from the amplification circuit 15 according to the temperature detected by the temperature / humidity sensor 22, or outputs the voltage amplification value without correction. To do. The AD conversion circuit 17 converts the voltage correction value or voltage amplification value output from the correction circuit 16 into a digital value and outputs the digital value to the CPU 12. Here, the functions of the corrosion sensor 21, the amplifier circuit 15, and the correction circuit 16 will be described in more detail with reference to FIG.

  FIG. 3 is a diagram schematically showing the change of the voltage amplification value output from the amplifier circuit 15 with respect to the temperature. In FIG. 3, the vertical axis represents the reference value [V] of the voltage amplification value, and the horizontal axis represents the temperature [° C.].

  In the present embodiment, the corrosion sensor 21 outputs current values as four ranges in accordance with the degree of corrosion at the mounting location. In the present embodiment, for example, the corrosion sensor 21 outputs a current value as the first range in the range of 0.01 [nA] to 30 [nA]. When the output current value exceeds 30 [nA], the corrosion sensor 21 outputs the current value as the second range. However, once the current value is output as the second range and the output current value is less than 30 [nA], the corrosion sensor 21 outputs the current value as the second range as it is. When the output current value is less than 1 [nA], the corrosion sensor 21 outputs the current value as the first range. That is, in the range of 1 [nA] to 30 [nA], the corrosion sensor 21 outputs the current value as the first range when the output current value is increasing, and the output current value is decreased. When the current value is output as the second range. As described above, the corrosion sensor 21 has hysteresis in the current value at the boundary of switching the range of the current value to be output. This prevents the current value output at the time of range switching from becoming unstable or becoming discontinuous and causing a step.

  And the corrosion sensor 21 outputs an electric current value as a 2nd range in the range of 1 [nA]-700 [nA]. Further, the corrosion sensor 21 outputs a current value as the third range in the range of 0.01 [μA] to 20 [μA]. Further, the corrosion sensor 21 outputs a current value as the fourth range in the range of 0.1 [μA] to 1500 [μA]. The corrosion sensor 21 has hysteresis as described above in the range of current values that overlap each range.

  Thus, the corrosion sensor 21 of the present embodiment is configured such that the output range of the current value is in the range from 0.01 [nA] which is the minimum current value to 1500 [μA] which is the maximum current value. Has been. In the present embodiment, the first range is an example of a first current range, and the second range to the fourth range are examples of a second current range.

  When the current value is output from the corrosion sensor 21 as the first range, the amplifier circuit 15 amplifies at the gain Ap1, and when the current value is output from the corrosion sensor 21 as the second range, the amplifier 15 amplifies at the gain Ap2. When the current value is output from the corrosion sensor 21 as the third range, the current value is amplified at the gain Ap3. When the current value is output from the corrosion sensor 21 as the fourth range, the current value is amplified at the gain Ap4. Here, Ap1> Ap2> Ap3> Ap4.

  In FIG. 3, the reference value V1 of the voltage amplification value is an example of the reference value of the voltage value output from the corrosion sensor 21 as the first range and amplified by the amplification circuit 15 with the amplification factor Ap1. The reference value V4 of the voltage amplification value is an example of a reference value of the voltage value output from the corrosion sensor 21 as the fourth range and amplified by the amplification circuit 15 at the amplification factor Ap4.

  As shown in FIG. 3, the reference value V4 of the voltage amplification value is substantially constant even when the temperature changes. On the other hand, the reference value V1 of the voltage amplification value gradually increases as the temperature T rises when the temperature is lower than the temperature threshold Tth (in this embodiment, for example, Tth = 25 ° C.), and the temperature is equal to or higher than the temperature threshold Tth. When the temperature T rises, it rapidly increases. When the inventor examined, when the current value was output from the corrosion sensor 21 as the first range, it was found that the same tendency was exhibited even if the current value was different. This is probably because the current value in the first range is as small as 0.01 to 30 [nA], so that it is greatly affected by temperature.

Therefore, in the present embodiment, when the current value is output from the corrosion sensor 21 as the first range, the following equation representing the correction value Cr (T) of the reference value V1 (T) of the voltage amplification value at the temperature T (1) is experimentally obtained in advance.
Cr (T) = A × T ⁵ + B × T ⁴ + C × T ³ + D × T ² + E × T + F (1)
In the above formula (1), A, B, C, D, E, and F are constants obtained experimentally. Further, the reference value Vth of the voltage amplification value corresponding to the temperature threshold value Tth is experimentally obtained in advance.

  The correction circuit 16 holds the correction value Cr (T) obtained in advance and the reference value Vth of the voltage amplification value. The correction value Cr (T) and the reference value Vth of the voltage amplification value are stored in the memory 11, and the correction circuit 16 acquires the correction value Cr (T) and the reference value Vth of the voltage amplification value from the memory 11. May be. In the present embodiment, as the correction value Cr (T), a quintic polynomial of the temperature T is adopted as shown in the above equation (1), but the present invention is not limited to this, and polynomials of other orders are adopted. May be.

In the vehicle 1, when the corrosion sensor 21 starts detecting the degree of corrosion, and the current value is output from the corrosion sensor 21 as the first range, the correction circuit 16 acquires the temperature T from the temperature / humidity sensor 22. The correction circuit 16 obtains the difference obtained by subtracting the correction value Cr (T) from the reference value V1 of the voltage amplification value at the temperature T obtained by the amplifier circuit 15 as the voltage amplification value at the temperature threshold Tth. The true change width from the reference value Vth is obtained. In other words, the correction circuit 16 sets the reference value of the voltage amplification value as
Vth + {V1-Cr (T)}
And The correction circuit 16 outputs a voltage correction value obtained by correcting the voltage amplification value output from the amplification circuit 15 using the reference value of the voltage amplification value to the AD conversion circuit 17.

  On the other hand, in the vehicle 1, when the corrosion sensor 21 starts detecting the degree of corrosion and a current value is output from the corrosion sensor 21 as the second range, the third range, or the fourth range, the correction circuit 16 includes an amplification circuit. The voltage amplification value output from 15 is output to the AD conversion circuit 17 as it is.

  The detection control unit 12a acquires a voltage correction value or a voltage amplification value output from the AD conversion circuit 17. The detection control unit 12a stores the acquired voltage correction value or voltage amplification value in the memory 11 as corrosion data. The detection control unit 12 a acquires temperature data and humidity data detected by the temperature / humidity sensor 22 via the connection cable 24. The detection control unit 12 a stores the acquired temperature data and humidity data in the memory 11.

  The communication control unit 12b (an example of a first communication control unit) transmits detection data (corrosion data, temperature data, and humidity data in the present embodiment) stored in the memory 11 from the antenna unit 13. The communication control unit 12 b transmits the detection data from the antenna unit 13 together with the child device ID stored in the memory 11.

  The antenna unit 40 (an example of the second antenna unit) receives detection data (corrosion data, temperature data, and humidity data in this embodiment) of the detection unit 20 by receiving radio waves radiated from the antenna unit 13. To do. As described above, the antenna unit 40 is connected to the data collection device 30 by the connection cable 41.

  The data collection device 30 collects detection data (corrosion data, temperature data, and humidity data in this embodiment) of the detection unit 20. The data collection device 30 includes a memory 31, a CPU 32, and other peripheral circuits. The data collection device 30 is constituted by a personal computer, for example.

  The memory 31 (an example of a storage unit) is configured by, for example, a semiconductor memory such as a flash memory, a hard disk, or another storage element. The memory 31 includes a memory that stores detection data of the detection unit 20, a memory that stores programs, a memory that temporarily stores data, and the like. Note that the memory 31 may be configured by a single memory element having an area for storing detection data of the detection unit 20, an area for storing a program, and an area for temporarily storing data.

  The CPU 32 functions as the communication control unit 33 by operating according to a program stored in the memory 31. The communication control unit (an example of a second communication control unit) 33 stores the detection data (corrosion data, temperature data, and humidity data in this embodiment) received by the antenna unit 40 in the memory 31. . In the present embodiment, the memory 11, the detection control unit 12a, the communication control unit 12b, the antenna unit 13, the amplifier circuit 15, the correction circuit 16, the antenna unit 40, and the communication control unit 33 constitute an example of a storage control unit.

  As described above, in the present embodiment, when the current value is output as the first range from the corrosion sensor 21, the correction circuit 16 is a reference for the voltage amplification value at the temperature T obtained by the amplification circuit 15. A difference obtained by subtracting the correction value Cr (T) from the value V1 is obtained as a true change width from the reference value Vth of the voltage amplification value at the temperature threshold Tth. Then, the correction circuit 16 sets the reference value of the voltage amplification value as Vth + {V1−Cr (T)}, and uses the reference value of the voltage amplification value to correct the voltage amplification value output from the amplification circuit 15. The correction value is output to the AD conversion circuit 17. Therefore, according to the present embodiment, even when a minute current value is output from the corrosion sensor 21, a value that accurately represents the degree of corrosion can be stored in the memory 31 of the data collection device 30.

(Modified embodiment)
(1) In the above embodiment, the corrosion sensor 21 is configured so that the output range of the current value is in the range from 0.01 [nA] which is the minimum current value to 1500 [μA] which is the maximum current value. However, it is not limited to this. The minimum current value and the maximum current value are examples, and other current values may be used.

  (2) In the above embodiment, the corrosion sensor 21 outputs current values in four ranges according to the degree of corrosion at the mounting location, but is not limited thereto. In addition, the lower limit current value and the upper limit current value that define each range in the above embodiment are also examples of the current value in the above embodiment, and are not limited to the above current value. The corrosion sensor only needs to output current values divided into two or more ranges.

  In that case, the voltage amplification value at the temperature T when the current value is output as the minimum range from the corrosion sensor to be used may be experimentally obtained in advance. Next, a temperature threshold value at which the voltage amplification value starts increasing may be obtained. Further, a voltage difference between the voltage amplification value at the temperature T and the voltage amplification value at the temperature threshold may be obtained for each temperature. The correction circuit 16 may hold the voltage difference for each temperature in advance. Also in this modified embodiment, a value that accurately represents the degree of corrosion can be stored in the memory 31 of the data collection device 30 as in the above embodiment.

  (3) In the above-described embodiment, the detection unit 20 is attached to four locations of the vehicle 1, for example, the engine room, the front wheel house, the outer plate of the lift gate, and the engine under cover, but is not limited thereto. . For example, the detection unit 20 may be attached to a place other than the above four places. Moreover, the detection part 20 may be attached to three or less places, and may be attached to five or more places. The wireless transmission device 10 may be attached in the vicinity of the detection unit 20.

  (4) In the above embodiment, the detection unit 20 includes the corrosion sensor 21 and the temperature / humidity sensor 22, but the detection unit 20 includes other sensors in addition to the corrosion sensor 21 and the temperature / humidity sensor 22. May be included. Further, the detection unit 20 may include a temperature sensor that detects only the temperature instead of the temperature and humidity sensor 22.

1 vehicle 10 wireless transmission device 11, 31 memory 12, 32 CPU
12a Detection control unit 12b, 33 Communication control unit 13, 40 Antenna unit 15 Amplification circuit 16 Correction circuit 20 Detection unit 21 Corrosion sensor 22 Temperature / humidity sensor 30 Data collection device

Claims (7)

A state detector that outputs a current value representing a state of a predetermined mounting location as an output current value;
A temperature detector for detecting the ambient temperature of the state detector;
A storage unit;
A storage control unit that stores the state of the mounting location in the storage unit;
With
The state detection unit is configured such that a range of the output current value is a range from a predetermined minimum current value to a predetermined maximum current value, and includes the first current value. A first mode for outputting the output current value as a current range and a second mode for outputting the output current value as a second current range not including the minimum current value;
In the first mode, the storage control unit stores a correction value obtained by correcting the output value corresponding to the output current value based on the temperature detected by the temperature detection unit in the storage unit, and the second mode. In the mode, the output value is stored in the storage unit.
Sensor signal value storage device. In the first mode, the storage control unit stores the correction value in the storage unit only when the temperature detected by the temperature detection unit is equal to or higher than a predetermined temperature threshold, and is detected by the temperature detection unit. When the temperature is less than the temperature threshold, the output value is stored in the storage unit,
The sensor signal value storage device according to claim 1. The minimum current value is 0.01 nA,
The first current range is a range of 0.01 nA or more and 0.03 μA or less.
The sensor signal value storage device according to claim 1. The state detection unit includes a corrosion sensor that outputs a current value corresponding to the degree of corrosion at the mounting location as the output current value.
The sensor signal value storage device according to claim 1. The storage control unit
A correction unit that is wired to the state detection unit and the temperature detection unit, generates the correction value from the output current value in the first mode, and generates the output value from the output current value in the first mode; ,
A first antenna unit for wirelessly transmitting the correction value or the output value;
A first communication control unit that controls wireless transmission of the correction value or the output value from the first antenna unit;
A second antenna unit for receiving the correction value or the output value transmitted from the first antenna unit;
A second communication control unit that stores the correction value or the output value received by the second antenna unit in the storage unit;
including,
The sensor signal value storage device according to claim 1. The state detection unit, the temperature detection unit, the storage unit, and the storage control unit are mounted on a vehicle.
The sensor signal value storage device according to claim 1. The state detection unit is attached outside the vehicle,
The sensor signal value storage device according to claim 6.

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