Sensor device

Abstract

To provide a technique allowing acquisition of an electrification state of a vehicle.SOLUTION: In a sensor device 1, a detection unit 10 detects a current flowing between a first constituent member 30 and a second constituent member 32 of a vehicle 90 on the basis of electric charges generated in a wheel 92 due to the travel of the vehicle 90. A comparison unit 14 compares a value related to the detected current with a threshold.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a sensor device mounted on a vehicle. [Background technology]

[0002] Patent Document 1 discloses a vehicle current sensor that measures a current value in a current path connected to a vehicle battery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6871028 Summary of the Invention [Problem to be solved by the invention]

[0004] The driving performance of a vehicle changes depending on the electrified state of the vehicle while it is running. The inventors recognized that it would be desirable to evaluate the driving performance of a vehicle depending on the electrified state of the vehicle. However, the technology of Patent Document 1 cannot acquire the electrified state of the vehicle.

[0005] An object of the present invention is to provide a technique that can acquire the charged state of a vehicle. [Means for solving the problem]

[0006] In order to solve the above problem, a sensor device according to one embodiment of the present invention includes a detection unit that detects a current flowing between a first component and a second component of the vehicle based on an electric charge generated in a wheel as the vehicle moves, and a comparison unit that compares a value related to the detected current with a threshold value. [Effects of the Invention]

[0007] According to the present invention, a technique can be provided that can acquire the charged state of a vehicle. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram schematically illustrating a vehicle equipped with a sensor device according to an embodiment; [Figure 2] FIG. 2 is an equivalent circuit diagram of the vehicle body periphery and the detection unit of the vehicle shown in FIG. 1. [Figure 3] 2 is a diagram showing an example of a current detected by the sensor device of FIG. 1. FIG. [Figure 4] 10 is a flowchart illustrating a process of the sensor device according to the embodiment. [Figure 5] FIG. 5(a) shows an equivalent circuit of a first configuration example of the sensor device, and FIG. 5(b) shows an equivalent circuit of a second configuration example of the sensor device. [Figure 6] FIG. 10 is a diagram illustrating a third configuration example of the sensor device. [Figure 7] 7 is a flowchart showing the processing of the sensor device of FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0009] FIG. 1 schematically shows a vehicle 90 equipped with a sensor device 1 according to an embodiment. FIG. 1 also shows the functional configuration of the sensor device 1. The vehicle 90 may be a vehicle that uses only an internal combustion engine as a driving force source, or may be an electric vehicle that uses an electric motor as a driving force source. The vehicle 90 may be a vehicle driven by a driver, or may be an autonomous vehicle.

[0010] It is known that a moving vehicle becomes charged to a negative voltage of several kV relative to the ground due to negative charge generated on the wheels by friction between the wheels and the road surface, which then transfers to the vehicle body. Experimental evidence has shown that installing devices that add air ions to the interior of the vehicle, devices that apply current or voltage to the vehicle body, or self-discharge static eliminators such as aluminum tape or Teflon®, can change the sensations experienced when going over bumps or during steering response. It is believed that this is because positive air ions in the air are attracted to the negatively charged vehicle surface and neutralize the vehicle's negative charge, which in turn changes aerodynamic characteristics such as pressure fluctuations on the vehicle surface.

[0011] In response to these phenomena, a technology for evaluating the quality of sensations is needed. The inventors focused on charge transfer in a vehicle and found that installing the above-mentioned device in a vehicle changes the charge transfer in the vehicle. The inventors also found that there is a correlation between the current flowing between certain parts of the vehicle and the vehicle's driving performance, and that sensing this current makes it possible to evaluate the quality of driving performance.

[0012] Therefore, the sensor device 1 of the embodiment senses the current flowing between two specific components of the vehicle 90 while it is running, and evaluates the driving performance of the vehicle 90, including its handling stability, based on the acquired current.

[0013] As shown in FIG. 1, the sensor device 1 includes a detection unit 10 and a processing unit 12. The detection unit 10 includes a current sensor and detects a current flowing between a first component 30 and a second component 32 of the vehicle 90 while the vehicle 90 is traveling, based on a negative charge generated on a wheel 92 due to the vehicle's travel. In the illustrated example, the wheel 92 is the left front wheel, but it may be a different wheel. The detection unit 10 is connected to the first component 30 and the second component 32 by an electric wire. In other words, the first component 30 and the second component 32 are short-circuited via the detection unit 10. The detection unit 10 supplies information about the detected current to the processing unit 12. The detection unit 10 can also be called a charge state sensing device that senses the charge state of the vehicle 90. The charge state of the vehicle 90 can also be referred to as the electrical state of the vehicle body or vehicle surface.

[0014] The first component 30 is a component near the wheel 92 to which negative charge generated in the wheel 92 due to friction between the wheel 92 and the ground while the vehicle is running is supplied. The first component 30 may be, for example, a kingpin of the wheel 92, or a bolt or nut near the wheel 92. The first component 30 may be a metal component that does not rotate with the wheel 92. The second component 32 is, for example, a body earth. The negative charge generated in the wheel 92 passes through the first component 30 and moves to the second component 32. It can also be said that the detection unit 10 detects the amount of negative charge that is generated in the wheel 92 due to friction between the wheel 92 and the ground and flows into the vehicle body.

[0015] 2 is an equivalent circuit diagram of the vehicle body periphery and the detection unit 10 of the vehicle 90 in FIG. 1. The current source I1 generates a current due to the movement of negative charges generated in the wheel 92 due to friction between the wheel 92 and the ground. The current source I1 is connected between the node N1 and the ground GND. The ground GND represents the earth.

[0016] Node N1 corresponds to the first component 30. Node N2 corresponds to the second component 32. In other words, node N2 corresponds to the body earth. A resistor R1 is connected between node N1 and node N2. Resistor R1 represents the electrical resistance of the vehicle body or the like between the first component 30 and the second component 32.

[0017] A detection unit 10 is also connected between node N1 and node N2 in parallel with resistor R1. That is, node N1 and node N2 are short-circuited via detection unit 10. For example, the resistance component of detection unit 10 may be sufficiently small compared to resistor R1. Therefore, almost all of the current flowing from node N2 to node N1 flows through detection unit 10, and substantially none flows through resistor R1. In this way, the current path between first component 30 and second component 32 via detection unit 10 serves as a bypass path for the current flowing from node N2 to node N1, allowing the current flowing from node N2 to node N1 to be indirectly measured.

[0018] Node N3 corresponds to the window or the surface of the vehicle body. Resistor R2 is connected between node N2 and node N3. Resistor R2 represents the electrical resistance between second component 32 and the window or the surface of the vehicle body.

[0019] Capacitor C1 and resistor R3 are connected in parallel between node N3 and ground GND. Capacitor C1 is the capacitance between the window or vehicle body surface and the ground. Resistor R3 represents the estimated equivalent discharge resistance. As mentioned above, the charge that reaches the window or vehicle body surface combines with charges of the opposite polarity in the air and is neutralized, returning to the ground, forming a closed loop.

[0020] FIG. 3 shows an example of the current detected by the sensor device 1 of FIG. 1. As an example, FIG. 3 shows the results of an experiment in which a vehicle 90 accelerated and decelerated on a straight road for approximately 50 seconds. Here, the vehicle 90 accelerated from 60 km / h to 100 km / h and then decelerated to 60 km / h. The experiment evaluated how the current flowing between the wheel 92 and the body earth, detected by the detection unit 10, changed depending on whether or not the aforementioned device, which has been confirmed to have an effect of improving handling stability through subjective evaluation, was used. Three trials were conducted with and without the device, and FIG. 3 shows the average change over the three trials. As shown in FIG. 3, in this example, it was confirmed that the current value was approximately 1.5 times higher when the device was used, which improved handling stability, compared to when the device was not used, which resulted in poor handling stability.

[0021] Therefore, the range of current values ​​from the first threshold value X1 to the second threshold value X2 that provides good driving stability is set in advance through experiments. Then, while the detection unit 10 senses the current value in real time, the processing unit 12 executes the following process based on the obtained current value, thereby making it possible to determine whether the current driving stability is good or bad.

[0022] Returning to FIG. 1, the processing unit 12 executes a process related to evaluation of the driving performance of the vehicle 90 based on the current detected by the detection unit 10. The processing unit 12 can also be called a driving stability determination device. The processing unit 12 has a comparison unit 14 and an evaluation unit 16.

[0023] The configuration of the processing unit 12 can be realized in hardware terms by the CPU, memory, and other LSI of any computer, and in software terms by a program loaded into memory, but here it is depicted as functional blocks realized by the cooperation of these. Therefore, it will be understood by those skilled in the art that these functional blocks can be realized in various forms using only hardware, only software, or a combination of both.

[0024] The comparison unit 14 receives information about the current detected by the detection unit 10 and compares a value related to the detected current with a threshold value. The threshold value includes a first threshold value X1 and a second threshold value X2. Specifically, the comparison unit 14 derives an average value of the current over a predetermined time period as a value related to the detected current, and compares the derived average value with the threshold value. The predetermined time period can be determined appropriately through experiments or simulations. The comparison unit 14 supplies the comparison result to the evaluation unit 16.

[0025] The evaluation unit 16 receives the comparison result from the comparison unit 14 and evaluates the driving performance of the vehicle 90, including the handling stability, based on the comparison result. The evaluation unit 16 evaluates the driving performance as poor if the condition that the average value of the current is equal to or greater than the first threshold value X1 and equal to or less than the second threshold value X2 is not satisfied. On the other hand, the evaluation unit 16 evaluates the driving performance as good if the average value of the current is equal to or greater than the first threshold value X1 and equal to or less than the second threshold value X2.

[0026] The evaluation unit 16 stores the data on the running performance as a log. The stored data is read out by an operator or the like. For example, at the vehicle design stage, a prototype vehicle may be run to collect data on the running performance, and the electrical resistance of the vehicle body may be designed to improve the running performance.

[0027] Although not shown, a detection unit 10 may be provided for each of the multiple wheels. The number of wheels to be provided with a detection unit 10 and which wheels to provide the detection unit 10 on may be determined appropriately through experiments or simulations. Each of the multiple detection units 10 supplies detected current information to the processing unit 12. The detection unit 10 provided for the right front wheel may detect the current flowing between the first component 30 and the second component 32 related to the right front wheel. The first component 30 related to the right front wheel may be a component near the right front wheel to which a negative charge generated in the right front wheel due to friction between the right front wheel and the ground is supplied, such as the kingpin of the right front wheel. The second component 32 related to the right front wheel may be a body earth located at a different position from the second component 32 related to the left front wheel, or may be a body earth located at the same position. When a detector 10 is also provided for the rear wheels, the detector 10 provided for the left rear wheel may detect the current flowing between the first component 30 and the second component 32 for the left rear wheel. The detector 10 provided for the right rear wheel may detect the current flowing between the first component 30 and the second component 32 for the right rear wheel. The first component 30 and the second component 32 for the left rear wheel and the right rear wheel, respectively, can be defined in the same way as the first component 30 and the second component 32 for the left front wheel and the right front wheel, respectively. The second component 32 for the rear wheels is preferably a body earth located at a different position from the second component 32 for the front wheels.

[0028] In this case, the comparison unit 14 may compare a value derived based on the current detected by each detection unit 10 with a threshold value. Specifically, the comparison unit 14 may derive an average value of the current detected by the detection unit 10 for each wheel over a predetermined period of time, derive a sum of the derived average values, and compare the sum with a threshold value. This can improve the accuracy of the comparison result and also improve the accuracy of the evaluation of driving performance.

[0029] Fig. 4 is a flowchart showing the processing of the sensor device 1 according to the embodiment. The processing of Fig. 4 is repeatedly executed while the vehicle 90 is traveling. Fig. 4 shows the processing when a detection unit 10 is provided for each of the four wheels.

[0030] The detection unit 10 detects the current for each wheel (S10), and the comparison unit 14 averages the current for each wheel (S12) and calculates the total value of the average currents for the four wheels (S14). If the condition that the total value is equal to or greater than the first threshold value X1 and equal to or less than the second threshold value X2 is not met (N in S16), the evaluation unit 16 determines that the driving stability is poor (S18) and the process ends. On the other hand, if the total value is equal to or greater than the first threshold value X1 and equal to or less than the second threshold value X2 (Y in S16), the evaluation unit 16 determines that the driving stability is good (S20) and the process ends.

[0031] According to the embodiment, it is possible to acquire the charged state of the vehicle 90. In addition, it is possible to evaluate the running performance of the vehicle 90.

[0032] Next, a detailed description will be given of the connection between the detection unit 10 and the processing unit 12. Fig. 5(a) shows an equivalent circuit of a first configuration example of the sensor device 1, and Fig. 5(b) shows an equivalent circuit of a second configuration example of the sensor device 1.

[0033] As shown in FIG. 5( a), in the first configuration example, the detection unit 10 and the processing unit 12 are electrically connected. That is, the detection unit 10 and the processing unit 12 are electrically connected by a conductor 20 such as an electric wire, and the detection unit 10 sends information about the measured current value to the processing unit 12 via the conductor 20. The detection unit 10 and the processing unit 12 are driven by the same power supply, and the grounds of the detection unit 10 and the processing unit 12 are connected to a common body earth E1. In this case, a small leakage current I2 may flow through the conductor 20. The occurrence of the leakage current I2 causes a voltage drop at the ground, which in turn causes a fluctuation in the voltage value received by the processing unit 12, affecting the measured current value and potentially resulting in an inaccurate comparison result by the comparison unit 14.

[0034] Therefore, as shown in FIG. 5(b), in the second configuration example, the detection unit 10 and the processing unit 12 are electrically insulated. Specifically, the detection unit 10 and the processing unit 12 are connected by a cable 22 such as an optical fiber, and the detection unit 10 sends information about the measured current value to the processing unit 12 via the cable 22 in an electrically insulated state using an optical signal or the like. Various known techniques can be used to send signals between the detection unit 10 and the processing unit 12 in an electrically insulated state. Furthermore, the detection unit 10 and the processing unit 12 are driven by separate power supply systems. The detection unit 10 is connected to a body earth E1, but the ground of the processing unit 12 is connected to an earth E2 that is different from the body earth E1.

[0035] This makes it possible to eliminate the influence of leakage current, and more accurate information on the current value can be received by the comparison unit 14. This makes it possible to improve the accuracy of the comparison results, and also improve the accuracy of the evaluation of the running performance.

[0036] Next, a description will be given of another example of the configuration of the sensor device 1. The following description will focus on the differences from the configuration in FIG.

[0037] FIG. 6 shows a third configuration example of the sensor device 1. The sensor device 1 further includes a charge adjusting unit 18. The charge adjusting unit 18 receives the comparison result from the comparing unit 14 and supplies a positive or negative charge to a third component 34 of the vehicle 90 based on the comparison result. The third component 34 is a component capable of transferring charge between it and the second component 32. In the example of FIG. 6, the third component 34 is a window. The third component 34 may also be, for example, a door. The third component 34 may be any component as long as it is a component capable of transferring charge between it and the second component 32.

[0038] The charge adjusting unit 18 is, for example, a current source that causes a current to flow between the body earth and the third component member 34, or a voltage source that applies a voltage between the body earth and the third component member 34. The charge adjusting unit 18 is a power supply that can change the direction of the supplied current or the positive or negative polarity of the supplied voltage depending on the comparison result by the comparing unit 14.

[0039] When the total current value of the four wheels is less than the first threshold value X1, the charge adjustment unit 18 supplies charge by applying a current or voltage to the third component 34 so that the current flowing from the second component 32 toward the first component 30 increases and the total current value becomes greater than the first threshold value X1 and less than the second threshold value X2.

[0040] On the other hand, when the total current value is greater than the second threshold value X2, the charge adjustment unit 18 supplies charge by applying a current or voltage to the third component 34 so that the current flowing from the second component 32 toward the first component 30 decreases and the total current value becomes greater than the first threshold value X1 and less than the second threshold value X2.

[0041] In this way, by supplying a positive or negative charge to the third component 34 depending on the comparison result, it is possible to maintain an appropriate charged state of the vehicle 90. As a result, it is possible to maintain good driving stability.

[0042] Fig. 7 is a flowchart showing the processing of the sensor device 1 of Fig. 6. The processing of Fig. 7 is repeatedly executed while the vehicle 90 is traveling. The processing from S10 to S20 is the same as that of Fig. 4.

[0043] In S16, if the condition that the total value is equal to or greater than the first threshold value X1 and equal to or less than the second threshold value X2 is not met (N in S16), the charge adjusting unit 18 adjusts the charge according to the comparison result (S22) following the process of S18, and the process ends. If the total value is equal to or greater than the first threshold value X1 and equal to or less than the second threshold value X2 (Y in S16), the charge adjusting unit 18 does not adjust the charge, and the process ends. Note that the evaluation unit 16 may not be provided. In that case, the processes of S18 and S20 are omitted.

[0044] The present invention has been described above based on the embodiments. However, the embodiments are merely examples, and it will be understood by those skilled in the art that various modifications are possible in the combination of each component and each treatment process, and that such modifications are also within the scope of the present invention. [Explanation of symbols]

[0045] 1...sensor device, 10...detection unit, 12...processing unit, 14...comparison unit, 16...evaluation unit, 18...charge adjustment unit, 30...first component, 32...second component, 34...third component, 90...vehicle, 92...wheel, E1...body earth.

Claims

1. a detection unit that detects a current flowing between the first component and the second component of the vehicle based on charges generated on the wheels as the vehicle moves; a comparison unit that compares a value relating to the detected current with a threshold value; A sensor device comprising:

2. The sensor device according to claim 1 , further comprising an evaluation unit that evaluates the running performance of the vehicle based on a comparison result by the comparison unit.

3. the first component is a component near the wheel to which electric charges generated by friction between the wheel and the ground are supplied, the second component is a body earth; The first component and the second component are short-circuited via the detection unit.

3. The sensor device according to claim 1 or 2.

4. The detection unit is provided for each of a plurality of wheels, the comparison unit compares a value derived based on the current detected by each detection unit with the threshold value; 3. The sensor device according to claim 1 or 2.

5. The sensor device according to claim 1 or 2, further comprising a charge adjustment unit that supplies charge to a third component of the vehicle that is capable of transferring charge between the second component and the third component based on the comparison result by the comparison unit.

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