Detection device and detection method

Abstract

This detection device comprises: a measurement instrument capable of detecting information pertaining to a tire of a vehicle using a prescribed electrode unit configured from a plurality of electrodes, the measurement instrument detecting an output value of a capacitance generated in the electrode unit due to contact or proximity of the tire; and a detection unit that detects the ground contact width of the tire by specifying the position of the electrode on the basis of the detected change in the output value.

Description

Detection device and detection method

[0001] The present disclosure relates to a detection device and a detection method.

[0002] For example, it has been disclosed that small switches are arranged and turned on / off by pressing them when a tire passes over them (see, for example, Japanese Patent Laid-Open Publication No. 11-16086).

[0003] Conventionally, mechanical switches have had problems with durability and environmental resistance.

[0004] The present disclosure aims to provide a detection device and a detection method that enable accurate detection of tire contact patch width while taking into consideration durability and cost, compared to when tires are monitored by camera or scanning observation.

[0005] The detection device according to a first aspect is a measuring instrument capable of detecting information related to a tire using a predetermined electrode unit composed of a plurality of electrodes, and includes: a measuring instrument that detects an output value of capacitance generated in the electrode unit when the tire of a vehicle comes into contact with or is very close to the electrode unit; and a detection unit that detects the tire contact width by identifying the position of the electrode based on a change in the detected output value.

[0006] In the detection device according to the second aspect, the measuring instrument has a plurality of electrodes arranged in parallel, and the detection unit detects the distance between the two electrodes at both ends in the tire width direction among the electrodes whose capacitance output value has changed to a predetermined threshold or more as the tire contact width.

[0007] In the detection device according to the third aspect, the plurality of electrodes are arranged so that the electrode width is between 1 and 5 mm, the electrode length is between 20 and 80 mm, and the gap between the electrodes is 2 mm.

[0008] In the detection device of the fourth aspect, a detection unit that detects the approach of the vehicle is further provided, and the detection unit obtains an initial value of the capacitance at the timing of detection by the detection unit, and uses the initial value to correct changes in the output value of each electrode of the electrode unit.

[0009] The detection method according to the fifth aspect is a measuring instrument capable of detecting information related to a tire using a predetermined electrode portion composed of a plurality of electrodes, which detects an output value of the capacitance generated in the electrode portion due to contact or close proximity of a vehicle tire, and a computer performs a process of detecting the tire contact width by identifying the position of the electrode based on the change in the detected output value.

[0010] The present disclosure has the advantage of enabling accurate detection of tire contact patch width while taking durability and cost into consideration, compared to when tires are monitored by camera or scanning observation.

[0011] FIG. 1 is an example of an image of a vehicle. FIG. 2 is a diagram showing an example of an installation image of a passing-type measuring instrument of this embodiment and the configuration of the detection device. FIG. 3 is an example of an image of the main body. FIG. 4 is a diagram showing details of the electrode unit. FIG. 5 is a graph showing an example of output change in electrostatic capacitance of the electrode unit. FIG. 6 is a graph extracting only electrodes whose output has changed to or above a threshold. FIG. 7 is a graph extracting only electrodes whose output has not changed to or above a threshold. FIG. 8 is an example of the configuration of the detection unit as a computer. FIG. 9 is a flowchart showing an example of the flow of detection processing according to this embodiment. FIG. 10 is a diagram showing the configuration of a modified example.

[0012] Hereinafter, the present embodiment will be described with reference to the drawings. Note that the same components and processes are given the same reference numerals throughout the drawings, and redundant explanations will be omitted. The dimensional proportions in the drawings are exaggerated for the sake of explanation, and may differ from the actual proportions.

[0013] First, the premise of this embodiment will be explained. Conventional tire condition monitoring involves measuring and observing tires mounted on vehicles, using methods such as image processing using camera capture and laser scanning. Conventional methods for detecting the contact width of a tire on the ground include providing transparent glass or resin on the surface where the tire passes and detecting the image, or arranging small switches and turning them on and off by pressing them as the tire passes. However, these conventional methods have issues with scratches and dirt on transparent surfaces such as glass, as well as the durability and environmental resistance of mechanical switches. Another alternative is to read the tire size printed on the side of the tire. However, this does not necessarily represent the actual tire contact width, as it varies depending on the tire size, type, and internal pressure. Therefore, it is difficult to easily detect the tire contact width with any desired accuracy while taking durability and cost into consideration. Therefore, in this embodiment, to solve the above problems, we propose a pass-through detection method using changes in electrode output values.

[0014] 1 is an example of an image of a vehicle. The vehicle 2 is equipped with a tire 1. In this embodiment, it is assumed that the contact patch width of the tire 1 is detected when the vehicle 2 passes. Note that the type of vehicle 2 is not particularly limited.

[0015] Fig. 2 is a diagram showing an example of installation of a pass-through measuring instrument according to this embodiment and the configuration of a detection device. Fig. 2 shows a vehicle, a tire 1 of the vehicle 2, a pass-through measuring instrument 3 for measuring the tire condition, a display 4, and a detection unit 5. The measuring instrument 3 is connected to the detection unit 5 (detection circuit). The display 4 displays any value output from the measuring instrument 3 and the detection unit 5. The measuring instrument 3 and the detection unit 5 are an example of a detection device disclosed herein.

[0016] FIG. 3 shows an example of the main body of the measuring device 3. The measuring device 3 is equipped with an electrode unit 3-a as a means for measuring the contact width of the tire 1 and a measuring unit 3-b for measuring any value. The measuring device 3 can detect various information about the tire 1 related to contact with the tire 1. The electrode unit 3-a may be made of an electrically conductive metal. The measuring unit 3-b measures, for example, the load of the vehicle 2, but other values ​​may also be used. Note that the electrode unit 3-a is preferably exposed and made of corrosion-resistant stainless steel or the like, but may also be made of other metals or may be covered with a corrosion-preventing protective cover of a few millimeters or less. It is also assumed that each part of the measuring device 3 is embedded in the road surface and installed flat.

[0017] FIG. 4 is a diagram showing details of the electrode unit 3-a. The electrode unit 3-a is composed of multiple electrodes with an arbitrary length 3-a-L and width 3-a-W, and the electrodes 3-a-1 are arranged at an arbitrary pitch 3-a-P. The electrode length 3-a-L of the electrode unit 3-a is preferably 20 to 80 mm, taking into account the sampling speed required to observe waveform changes when a tire passes and the contact length of the tire 1, assuming a vehicle passing speed of approximately 5 km / h. Furthermore, the electrode width 3-a-W is preferably approximately 1 to 5 mm in terms of sensitivity and strength, and the electrode pitch 3-a-P is preferably set to provide a gap of approximately 2 mm between electrodes to prevent interference with adjacent electrodes.

[0018] When the vehicle 2 passes the measuring device 3, the tire 1 passes over the electrode portions 3-a installed on the right and left wheels of the measuring device 33 and over the measuring device 3-b that measures an arbitrary value. As the tire 1 passes over the electrode portions 3-a, the contact width of the tire 1 is detected. As the tire 1 advances, it passes over the means 3-a that measures the contact width of the tire 1 while gradually increasing its contact, and as the tire 1 advances further, it comes into complete contact with the electrode portion 3-a. Furthermore, as the tire 1 advances further, the tire 1 reduces its contact with the electrode portion 3-a, and eventually it is completely separated. Note that if the electrode portion 3-a is covered with a protective cover to prevent corrosion, the tire 1 will be in very close proximity to the electrode portion 3-a.

[0019] As described above, the measuring device 3 detects the output value of the capacitance generated in the electrode unit 3-a due to contact with the tire 1 of the vehicle 2. In each of the electrodes 3-a-1 of the electrode unit 3-a, the output value of the capacitance generated in that electrode changes depending on the contact state of the tire 1. Note that, for the sake of convenience in the following explanation, the reference numerals of the electrodes 3-a-1 may be omitted.

[0020] The detection unit 5 detects the tire contact width by identifying the position of the electrodes based on changes in the detected capacitance output value. A detection method using changes in capacitance output will be described below.

[0021] FIG. 5 is a graph showing an example of the change in capacitance output of the electrode unit 3-a. The graph shown in FIG. 5 shows the change in output from electrode 3-a-1 when one side of the tire 1 passes through the means 3-a for measuring the tire 1 contact width. The vertical axis represents the capacitance index, and the horizontal axis represents time (ms). Changes in capacitance output are detected from electrodes P1 to P16. Of the electrodes arranged in parallel, P1 to P16 are the electrodes from which capacitance output was detected, with P1 and P16 being the electrodes at both ends where output was detected. Note that only the symbols of representative electrodes necessary for explanation are shown, and other electrodes are omitted. As shown in the graph in FIG. 5, the value of the electrode in contact with the tire 1 drops sharply, while the value of the electrodes not in contact shows little or only a slight change.

[0022] FIG. 6 is a graph showing only electrodes whose output changed above the threshold. FIG. 7 is a graph showing only electrodes whose output did not change above the threshold. As shown in FIG. 6, it can be seen that P1 and P12 are the two electrodes whose output changed above the threshold. P5 at the top of FIG. 7 shows a slight change in output because electrode 3-a-1 was in the tire groove and came very close to electrode 3-a-1. In this way, the detection unit 5 can detect the tire width by identifying the positions of the electrodes at both ends where the capacitance output changed. The distance between the two electrodes, which is the tire width to be detected, can be calculated by adding the sum of the electrode widths of the electrodes at both ends and the electrode located inside them plus the sum of the inter-electrode spacing.

[0023] The detection unit 5 is configured as a computer circuit. As shown in Fig. 8, the detection unit 5 is configured using, for example, a computer 10. The computer 10 includes a CPU (Central Processing Unit) 10A, which is an example of a processor, a RAM (Random Access Memory) 10B used as a temporary work area for the CPU 10A, a non-volatile memory 10C, and an input / output interface (I / O) 10D. The CPU 10A, RAM 10B, non-volatile memory 10C, and I / O 10D are connected to each other via a bus 10E.

[0024] The nonvolatile memory 10C is an example of a storage device that maintains stored information even when power supplied to the nonvolatile memory 10C is interrupted. For example, a semiconductor memory is used, but a hard disk may also be used. Information that needs to be continuously stored even when power to the detection unit 5 is interrupted is stored in the nonvolatile memory 10C. The nonvolatile memory 10C also stores an information processing program for executing the detection process. The nonvolatile memory 10C also functions as a circuit for storing data from the detection unit 5, and stores various information for detecting the tire contact width, such as information on the position of each electrode and the distance between the electrodes. The nonvolatile memory 10C does not necessarily have to be built into the computer 10, and may be, for example, a portable storage device that is detachable from the computer 10. Furthermore, the computer 10 may have a general configuration, so a description of other components will be omitted.

[0025] The I / O 10D is connected to, for example, a communication unit 11, an input unit 12, a display unit 13, and a temperature sensor 14, but each unit may be omitted. In addition, the I / O 10D is connected to a plurality of temperature sensors 14, each of which is a thermometer that measures the outside air temperature around the measuring device 3.

[0026] (Processing Flow) Next, the flow of the detection processing according to this embodiment will be described. Fig. 9 is a flowchart showing an example of the flow of the detection processing according to this embodiment. When the vehicle 2 passes and the tire 1 comes into contact with the measuring device 3, a series of detection processing is performed.

[0027] In step S10, CPU 10A obtains the output value of the capacitance detected at each of electrodes 3-a-1 of electrode unit 3-a.

[0028] In step S12, CPU 10A identifies electrodes that have experienced a change in output value of each electrode that is equal to or greater than a predetermined threshold value.

[0029] In step S14, CPU 10A identifies the position of the electrode where a change equal to or greater than the threshold value has occurred.

[0030] In step S16, CPU 10A detects the distance between the two electrodes at both ends in the tire width direction as the tire contact patch width based on the identified electrode positions.

[0031] As described above, the detection process of this embodiment makes it possible to accurately detect the tire contact patch width while taking durability and cost into consideration.

[0032] (Modification) As shown in FIG. 10 , the configuration of the above embodiment may further include a detection unit 7, such as a camera or sensor, for detecting the approach of a vehicle 2 to the measuring instrument 3. The detection unit 5 acquires the initial capacitance value of each electrode 3-a-1 of the electrode unit 3-a upon detection by the detection unit 7, and corrects changes in the output value of each electrode 3-a-1 using the initial value. This allows detection to be performed taking into account the state of each electrode, which has a different initial value. Although variations are expected to increase depending on disturbances such as temperature and other weather conditions, this makes it possible to correct variations in the output of each electrode and detect changes in capacitance output. Furthermore, when the detection unit 7 detects approach, the measuring instrument 3 may be activated and perform detection, thereby saving power.

[0033] While one form of the detection device has been described above using the embodiment, the disclosed form is merely an example, and the form of the detection device is not limited to the scope described in the embodiment. Various changes or improvements can be made to each embodiment without departing from the gist of the present disclosure, and forms of the detection device with such changes or improvements are also included in the technical scope of the disclosure.

[0034] In the above embodiment, the detection process shown in Fig. 9 is implemented by the CPU 10A of the computer, but the same process as shown in the flowchart may be executed by another arithmetic circuit.

[0035] In addition, in each of the above embodiments, an example has been described in which the information processing program is stored in the nonvolatile memory 10C. However, the storage destination of the information processing program is not limited to the nonvolatile memory 10C. The information processing program may also be provided in a form recorded on a computer-readable storage medium.

[0036] For example, the information processing program may be provided in a form recorded on an optical disk such as a CD-ROM (Compact Disk Read Only Memory), a DVD-ROM (Digital Versatile Disk Read Only Memory), or a Blu-ray disc. The information processing program may also be provided in a form recorded on a portable semiconductor memory such as a USB (Universal Serial Bus) memory or a memory card. The non-volatile memory 10C, a CD-ROM, a DVD-ROM, a Blu-ray disc, a USB, and a memory card are examples of non-transitory storage media.

[0037] Furthermore, the CPU 10A may download an information processing program from an external device via the communication unit 11 and store the downloaded information processing program in the nonvolatile memory 10C.

[0038] In the embodiment, the CPU 10A has been used as an example of a general-purpose processor. However, in the embodiment, the term "processor" refers to a processor in a broad sense, and includes not only a general-purpose processor such as the CPU 10A, but also a dedicated processor (for example, a GPU: Graphics Processing Unit, an ASIC: Application Specific Integrated Circuit, an FPGA: Field Programmable Gate Array, a programmable logic device, etc.).

[0039] Furthermore, the operation of the processor in the above-described embodiments may not only be performed by a single processor, but may also be performed by multiple processors working together, or may be performed by multiple processors located in physically separate locations working together.

[0040] All publications, patent applications, and technical standards mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, or technical standard was specifically and individually indicated to be incorporated by reference.

[0041] The disclosure of Japanese Patent Application No. 2024-082093, filed on May 20, 2024, is incorporated herein by reference in its entirety. In addition, all documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually indicated to be incorporated by reference.

Claims

1. A measuring device capable of detecting information related to tires using a predetermined electrode section composed of multiple electrodes, which detects the output value of the capacitance generated in the electrode section when a vehicle tire comes into contact with or is very close to the electrode section, and a detection section which detects the tire contact width by identifying the position of the electrode based on changes in the detected output value.

2. The detection device according to claim 1, wherein the measuring device is provided with a plurality of electrodes arranged in parallel, and the detection unit detects the tire contact width as the distance between two electrodes at both ends in the tire width direction, among the electrodes whose capacitance output value has changed to a predetermined threshold or more.

3. The detection device according to claim 2, wherein the plurality of electrodes have an electrode width of 1 to 5 mm, an electrode length of 20 to 80 mm, and are installed with a gap between the electrodes of 2 mm.

4. The detection device according to claim 1, further comprising a detection unit that detects the approach of the vehicle, wherein the detection unit obtains an initial value of capacitance at the timing of detection by the detection unit, and uses the initial value to correct changes in the output value of each electrode of the electrode unit.

5. A detection method in which a measuring instrument is capable of detecting information related to tires using a predetermined electrode section composed of multiple electrodes, and detects the output value of the capacitance generated in the electrode section when a vehicle tire comes into contact with or is very close to the electrode section, and a computer executes a process to detect the tire contact width by identifying the position of the electrode based on the change in the detected output value.

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