Snow melting device

Abstract

To provide a snow melting device capable of inexpensively realizing a constitution for melting snow by detecting accumulated snow.SOLUTION: The snow melting device illuminates a road surface by controlling a light source (S53). The snow melting device acquires first information indicating intensity for each wavelength of reflected light from a road surface illuminated by the light source (S55). The snow melting device determines whether snow is accumulated on the road surface based on the acquired first information (S61). If it is determined that snow is accumulated on the road surface (S63: YES), the snow melting device heats the road surface (S65).SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a snow melting device. [Background technology]

[0002] Snow melting devices that melt snow on road surfaces are known. When snow melting devices detect snow on the road surface, they melt the snow by circulating a heated heat medium through heat dissipation pipes buried in the road surface. For example, a road snow detection device described in Patent Document 1 uses a camera to capture images of the road surface. The road snow detection device extracts the color brightness ratio from the obtained image and determines whether or not snow is present by determining the distribution of these values. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-213674 Summary of the Invention [Problem to be solved by the invention]

[0004] The road snow detection device described above requires a camera and a controller for image analysis to detect snow accumulation, which can lead to the device itself being expensive.

[0005] An object of the present invention is to provide a snow melting device that can inexpensively realize a configuration for detecting and melting accumulated snow. [Means for solving the problem]

[0006] The snow melting device of claim 1 is characterized by comprising an irradiation means for controlling a light source to illuminate a road surface, a first acquisition means for acquiring first information indicating the intensity for each wavelength of reflected light from the road surface illuminated by the light source controlled by the irradiation means, a determination means for determining whether or not there is snow on the road surface based on the first information acquired by the first acquisition means, and a heating means for heating the road surface when the determination means determines that there is snow on the road surface.

[0007] The determination means of the snow melting device according to claim 2 may determine that snow is present on the road surface when the color identified by the first information is white.

[0008] The judgment means of the snow melting device of claim 3 may determine that the color identified by the first information is white if the intensities of the wavelengths of R, G, and B indicated by the first information are all equal to or greater than a first threshold value stored in a memory unit.

[0009] In the snow melting device of claim 4, a reference portion consisting of a standard color may be provided on at least a portion of the road surface, and the first acquisition means may acquire the first information indicating the intensity of each wavelength of the reflected light when the reference portion is provided on the road surface.

[0010] In the snow melting device described in claim 5, a reference portion consisting of a standard color may be provided on at least a portion of the road surface, and a first setting means may be provided which determines the first threshold value based on the first information indicating the intensity of each wavelength of the reflected light when the reference portion is provided and there is snow, and stores and sets the first threshold value in a memory unit.

[0011] The snow melting device described in claim 6 is provided with a designated acquisition means for acquiring the first information indicating the intensity of each wavelength of the reflected light from the road surface illuminated by the light source in response to instructions from a user, and the first setting means may determine the first threshold value based on the first information acquired by the designated acquisition means, and store and set it in the memory unit.

[0012] In the snow melting device of claim 7, a reference portion consisting of a standard color is provided on at least a part of the road surface, and a first setting means is provided which determines a second threshold value for determining that there is no snow based on the first information indicating the intensity of each wavelength of the reflected light when the reference portion is provided and there is no snow, and stores and sets the second threshold value in a memory unit, and the determination means may determine that there is no snow on the road surface if the intensity of each wavelength of R, G, and B indicated by the second information is all below the second threshold value stored in the memory unit.

[0013] The snow melting device of claim 8 is provided with a designation acquisition means for acquiring the first information indicating the intensity of each wavelength of the reflected light from the road surface illuminated by the light source in response to instructions from a user, and the first setting means may determine the second threshold value based on the first information acquired by the designation acquisition means, and store and set it in the memory unit.

[0014] The first setting means of the snow melting device of claim 9 may further determine a first threshold value for determining that snow is present on the road surface based on the second threshold value, and may store and set the first threshold value and the second threshold value in the memory unit.

[0015] The snow melting device of claim 10 may further include a second acquisition means for acquiring second information output from a snowfall sensor, and the determination means may determine whether there is snow on the road surface based on the first information acquired by the first acquisition means and the second information acquired by the second acquisition means.

[0016] The snow melting device of claim 11 further includes a third acquisition means for acquiring third information output from a thermistor capable of measuring the temperature of the road surface, and the determination means may determine whether there is snow on the road surface based on the first information acquired by the first acquisition means and the third information acquired by the third acquisition means.

[0017] The snow melting device of claim 12 further comprises a second acquisition means for acquiring second information output from a snowfall sensor, a third acquisition means for acquiring third information output from a thermistor capable of measuring the temperature of the road surface, and a second setting means for setting which of the first information acquired by the first acquisition means, the second information acquired by the second acquisition means, and the third information acquired by the third acquisition means is to be valid, and the determination means may determine whether there is snow on the road surface based on the information set as valid by the second setting means among the first information, the second information, and the third information.

[0018] In the snow melting device of claim 13, the light source may be a lighting device that maintains the brightness of the road surface, and may include a changer that can change the distance between the lighting device and the road surface.

[0019] The first acquisition means of the snow melting device of claim 14 may acquire the first information from a color sensor. [Effects of the Invention]

[0020] The snow melting device of claim 1 determines whether there is snow on the road surface based on first information indicating the intensity of each wavelength of reflected light. In this case, it is possible to determine whether there is snow on the road surface without using a camera or a controller required for image analysis. Therefore, the snow melting device can inexpensively realize a configuration that melts snow by heating it. Furthermore, the snow melting device obtains the first information indicating the intensity of each wavelength of reflected light while the road surface is illuminated by a light source. In this case, the snow melting device can accurately determine whether there is snow on the road surface.

[0021] According to the snow melting device of claim 2, the amount of snow on the road surface can be determined by color from the intensity of each wavelength of the reflected light acquired as the first information.

[0022] The snow melting device of claim 3 can determine the amount of snow on the road surface by color based on the intensity of each wavelength of R, G, and B in the reflected light.

[0023] The snow melting device of claim 4 can increase the contrast between whether there is snow on the road surface at the position where the reference portion is provided, and therefore the snow melting device can accurately determine whether there is snow on the road surface.

[0024] The snow melting device according to claim 5 can accurately determine whether there is snow on the road surface.

[0025] In the snow melting device according to claim 6, the first threshold can be set with high accuracy by specifying when there is snow and having the snow melting device acquire the first information.

[0026] The snow melting device of claim 7 can accurately determine whether there is snow on the road surface and whether there is no snow on the road surface.

[0027] A user of the snow melting device according to claim 8 can set the second threshold value with high accuracy by specifying a time when there is no snow and having the snow melting device acquire the first information.

[0028] In the snow melting device of claim 9, the first threshold value can be automatically determined based on the second threshold value without acquiring the first information.

[0029] The snow melting device according to claim 10 can improve the accuracy of determining whether there is snow on the road surface compared to when the determination is made based only on the first information.

[0030] The snow melting device of claim 11 can improve the accuracy of determining whether there is snow on the road surface compared to when the determination is made based only on the first information.

[0031] In the snow melting device of claim 12, the user can set which of the first information, the second information, and the third information is to be valid depending on the environment in which the snow melting device is used. In this case, the snow melting device can improve the accuracy of determining snow accumulation regardless of the environment in which it is used.

[0032] The brightness of the road surface illuminated by the lighting device can be maintained regardless of the environment or time of day the snow melting device of claim 13 is used in. In this case, the snow melting device can improve the accuracy of snow accumulation determination regardless of the environment or time of day it is used in.

[0033] The snow melting device of claim 14 uses a color sensor, which is cheaper than a camera, so that a configuration for heating and melting accumulated snow can be realized at low cost. [Brief explanation of the drawings]

[0034] [Figure 1] 1 is a schematic diagram showing the configuration of a snow melting device 1. FIG. [Figure 2] 1 is a diagram showing a lighting device 90 and a color sensor 91. FIG. [Figure 3] 2 is a block diagram showing the electrical configuration of the snow melting device 1. FIG. [Figure 4] 10 is a table showing determination conditions. [Figure 5] 10 is a flowchart showing a first setting process. [Figure 6] 10 is a flowchart showing a second setting process. [Figure 7] 10 is a flowchart showing a main process. [Figure 8] 10 is a flowchart showing a first setting process in a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0035] A snow melting device 1 according to one embodiment of the present invention will be described below with reference to the drawings. These drawings are used to explain the technical features that can be adopted by the present invention. Unless otherwise specified, the structure of the device described below is not intended to be limiting and is merely an illustrative example.

[0036] <Summary> Snow melting device 1 is a device for eliminating snow accumulation by melting snow on the road surface. As shown in Fig. 1, snow melting device 1 includes hot water supply devices 2 to 4, a heating pipe 19, a sensor unit 9A, and a lighting support part 900 (see Fig. 2).

[0037] Snow melting device 1 determines whether or not there is snow accumulation based on information detected by sensor unit 9A. If it is determined that there is snow accumulation, water heater 2 heats the antifreeze liquid, which is a heat medium, using burner 50. The heated antifreeze liquid circulates through heating pipe 19. Heating pipe 19 is a repeatedly bent pipe that is buried in the snow melting target area 6 of the road surface. As the heated antifreeze liquid flows through heating pipe 19, heating pipe 19 releases heat, raising the temperature of the ground in snow melting target area 6. This melts the snow in snow melting target area 6. The antifreeze liquid that has flowed through heating pipe 19 returns to water heater 2 and is heated again. The above series of operations in snow melting device 1 is called "snow melting operation."

[0038] <Hot water supply device 2> Water heater 2 shown in Fig. 1 functions as a main unit. At the bottom of housing 2A of water heater 2, there are provided gas inlet 41 through which gas flows in, water inlet 42 through which antifreeze liquid that has returned after flowing through heating pipe 19 flows in, and water outlet 43 through which antifreeze liquid heated within housing 2A flows out. Burner 50 is provided in the combustion chamber of housing 2A. A gas supply pipe 45 connected to gas inlet 41 is connected to burner 50.

[0039] Gas solenoid valve 51, which opens and closes the gas flow path, is provided on the upstream side of gas flow in gas supply pipe 45. Gas proportional valve 52, which adjusts the gas flow rate and thereby the thermal power of burner 50, is provided downstream of gas supply pipe 45. Pipe 46, through which antifreeze liquid flows, is provided between water inlet 42 and water outlet 43. A heat exchanger (not shown) is provided midway along pipe 46. A flow rate sensor 56, which detects the return flow rate of antifreeze liquid flowing through pipe 46, and a return temperature thermistor 55, which detects the return temperature of the antifreeze liquid (the temperature of water entering hot water heater 2), are provided on pipe 46 upstream of the heat exchanger.

[0040] Water heating apparatus 2 is further provided with remote control device 36, lighting device 90, and sensor unit 9A. Sensor unit 9A includes a color sensor 91, a snowfall sensor 92, and a thermistor 93.

[0041] The remote control device 36 instructs the operation of the snow melting device 1. The remote control device 36 is provided with an operation switch 36A for executing normal operation of the snow melting device 1.

[0042] As shown in FIG. 2, the lighting device 90 illuminates a portion of the snow melting target area 6 on the road surface (hereinafter referred to as the "illumination area 6A") with light, thereby maintaining the brightness of the illumination area 6A. The lighting device 90 is supported by a lighting support part 900 at a position spaced above the snow melting target area 6. The lighting support part 900 can change the vertical distance between the lighting device 90 and the snow melting target area 6 by changing the height of the lighting device 90. A reference part Rp is provided in a portion of the illumination area 6A. The reference part Rp is, for example, a plate of a reference color. For example, the reference color is black. The reference part Rp is covered with snow when there is snow accumulation.

[0043] The color sensor 91 is a photoelectric sensor including a light-emitting unit and a light-receiving unit. The color sensor 91 emits light from the light-emitting unit toward a reference unit Rp provided in the irradiation area 6A. The color sensor 91 receives the light reflected from the reference unit Rp using the light-receiving unit. The light-receiving unit detects the light intensities of R (red), G (green), and B (blue) in the received reflected light. The color sensor 91 outputs the detected light intensities for each of R, G, and B as information (hereinafter referred to as "first information") indicated by 256 gradations (0 to 255). Hereinafter, when the light intensity of R is represented as Lr, the light intensity of G as Lg, and the light intensity of B as Lb, the light intensities of R, G, and B will be represented as (Lr, Lg, Lb).

[0044] The snow sensor 92 is a moisture detection sensor that detects whether snow is falling. The snow sensor 92 has a temperature sensor and an electrode sensor. The electrode sensor detects moisture by melting accumulated snow with a heater. If the temperature measured by the temperature sensor is below a predetermined temperature and moisture is detected by the electrode sensor, the snow sensor 92 outputs information indicating that snow is falling (hereinafter referred to as "second information"). The thermistor 93 is provided in the irradiation area 6A of the snow melting target area 6 and is capable of measuring the temperature of this area. The thermistor 93 outputs information indicating the measured temperature (hereinafter referred to as "third information").

[0045] Water heaters 3 and 4 function as sub-units. Water heaters 3 and 4 have almost the same configuration as water heater 2. Gas inlet 61, water inlet 62, and water outlet 63 are provided at the bottom of housing 3A of water heater 3. Gas inlet 81, water inlet 82, and water outlet 83 are also provided at the bottom of housing 4A of water heater 4. Burner 50, gas supply pipe 45, gas solenoid valve 51, gas proportional valve 52, and piping 46, similar to those of water heater 2, are provided within housings 3A and 4A of water heaters 3 and 4, respectively.

[0046] <Piping configuration> One end of heating pipe 19 on the downstream side where antifreeze liquid flows is connected to one end of first return pipe 7. The other end of first return pipe 7 is connected to the bottom of air separator 8, which separates air from the antifreeze liquid supplied from first return pipe 7. One end of second return pipe 9 is further connected to the bottom of air separator 8. The other end of second return pipe 9 is provided with branch section 21, which branches into two flow paths. One end of branch section 21 is connected to one end of third return pipe 10, which supplies antifreeze liquid to water heaters 2 to 4, and the other end is connected to one end of bypass pipe 18, which will be described later.

[0047] Third return pipe 10 extends across water heaters 2 to 4. Third return pipe 10 is provided with connections 22, 23, and 24, arranged in this order from upstream to downstream in the direction of antifreeze flow. One end of branch pipe 11 is connected to connection 22. The other end of branch pipe 11 is connected to water inlet 42 of water heater 2. One end of branch pipe 12 is connected to connection 23. The other end of branch pipe 12 is connected to water inlet 62 of water heater 3. One end of branch pipe 13 is connected to connection 24. The other end of branch pipe 13 is connected to water inlet 82 of water heater 4. A water heater pump 31 is provided upstream of third return pipe 10, between branch 21 and connection 22. Water heater pump 31 adjusts the flow rate of antifreeze supplied to water heaters 2 to 4. Water heater pump 31 is a DC pump driven by a DC power source. Therefore, when water heater-side pump 31 is driven, the antifreeze liquid flowing through third return pipe 10 flows from connections 22, 23, 24 through branch pipes 11, 12, 13 into water heaters 2, 3, 4.

[0048] On the other hand, one end of a supply pipe 17 is connected to one end of the heating pipe 19 on the upstream side of the antifreeze flow direction, through which the antifreeze heated in the water heaters 2 to 4 flows. The supply pipe 17 extends across the water heaters 2 to 4, similar to the third return pipe 10. The supply pipe 17 is provided with connections 25, 26, and 27 in this order from the downstream side to the upstream side in the direction of antifreeze flow. One end of a branch pipe 14 is connected to connection 25. The other end of branch pipe 14 is connected to water outlet 43 of the water heater 2. One end of branch pipe 15 is connected to connection 26. The other end of branch pipe 15 is connected to water outlet 63 of the water heater 3. One end of branch pipe 16 is connected to connection 27. The other end of branch pipe 16 is connected to water outlet 83 of the water heater 3. In each of the water heaters 2 to 4, The heated antifreeze flows from each outlet 43 , 63 , 83 through each branch pipe 14 , 15 , 16 , and flows from connecting parts 25 , 26 , 27 to the outflow pipe 17 where they join together and flow toward the heating pipe 19 .

[0049] Furthermore, a junction 28 is provided in the supply pipe 17 downstream of the connection 25. A bypass pipe 18 is provided between the branching point 21 of the second return pipe 9 and the junction 28 of the supply pipe 17. The bypass pipe 18 allows a portion of the antifreeze liquid that has flowed through the second return pipe 9 to flow directly into the supply pipe 17 without passing through the hot water heaters 2-4. A heat dissipation pump 32 is provided in the bypass pipe 18. The heat dissipation pump 32 adjusts the flow rate of the antifreeze liquid flowing through the bypass pipe 18, thereby adjusting the overall circulation amount in the snow melting device 1. The heat dissipation pump 32 is also a DC pump driven by a DC power source. A supply temperature thermistor 58 is provided in the supply pipe 17 downstream of the junction 28 to detect the supply temperature of the antifreeze liquid flowing through the supply pipe 17.

[0050] A radiator cap 73 with an air bleed valve 72 is provided above the air separator 8. The radiator cap 73 is provided with a communication pipe 74 through which excess antifreeze in the air separator 8 flows. The communication pipe 74 is inserted all the way to the bottom inside an expansion tank 70 provided next to the air separator 8. The expansion tank 70 absorbs the expansion of the antifreeze from the air separator 8 as the temperature of the antifreeze circulating through the snow melting device 1 rises. Conversely, if negative pressure occurs within the passage of the snow melting device 1, the expansion tank 70 supplies antifreeze to the air separator 8. An antifreeze refill port 75 for supplying antifreeze into the expansion tank 70 and a pair of water level electrodes 76 and 77 for detecting the water level within the tank are provided above the expansion tank 70. An overflow water drain pipe 78 is provided at the upper side of the expansion tank 70 to discharge antifreeze that overflows from the tank to the outside.

[0051] <Electrical configuration> As shown in FIG. 3, the snow melting device 1 includes a control device 5 in the housing 2A (see FIG. 1) of the hot water supply device 2. The control device 5 includes a CPU 101 that controls the snow melting device 1. The CPU 101 is connected to a ROM 102, a RAM 103, and an EEPROM 104. The ROM 102 is a non-volatile memory element that stores programs for a first setting process (see FIG. 5), a second setting process (see FIG. 6), and a main process (see FIG. 7), which will be described later, as well as initial values ​​of various data. The RAM 103 is a readable and writable volatile memory element that temporarily stores programs currently being executed and stores various data. The EEPROM 104 is a non-volatile memory element that stores various thresholds (a first threshold Th1, a second threshold Th2, and a temperature threshold Tt), which will be described later. The control device 5 also includes a battery 20 as a backup power source.

[0052] The CPU 101 is connected to a gas proportional valve drive circuit 52A, a flame rod circuit 116, an igniter circuit 117, a water heater side pump drive circuit 31A, a heat radiation side pump drive circuit 32A, a display drive circuit 37A, a lighting drive circuit 90A, an input / output (I / O) interface 121, and the like. The gas proportional valve drive circuit 52A is connected to a gas proportional valve 52. The flame rod circuit 116 is connected to a frame rod 106. The frame rod 106 detects misfires. The igniter circuit 117 is connected to an igniter 107. The igniter 107 ignites the burner 50. The water heater side pump 31 is connected to the water heater side pump drive circuit 31A. The heat radiation side pump 32 is connected to the heat radiation side pump drive circuit 32A. The display drive circuit 37A is connected to a display 37. The display unit 37 displays various screens such as error indications. The illumination device 90 is connected to the illumination drive circuit 90A. The safety circuit 114 is driven by a detection signal output from the flame rod circuit 116.

[0053] The input / output interface 121 is connected to the outgoing temperature thermistor (TH) 58, the return temperature thermistor (TH) 55, the flow rate sensor 56, the road surface temperature sensor 35, the water level electrodes 76, 77, the color sensor 91, snowfall sensor 92, and thermistor 93 of the sensor unit 9A, and the remote control device 36. The remote control device 36 is provided with an input section (not shown) for various inputs and settings, as well as an operation switch 36A for executing normal operation.

[0054] <Determination conditions> 4 shows five determination conditions (first to fifth conditions) when the CPU 101 determines that there is snow on the road surface in the snow melting target area 6. The user can set any one of the five determination conditions in the snow melting device 1.

[0055] Under the first condition, whether there is snow is determined based on the first information output from the color sensor 91. More specifically, if the color identified by the first information is white, it is determined that there is snow. Whether the color identified by the first information is white is determined by comparing the light intensities of R, G, and B with a first threshold value Th1 (Thb(1), Thg(1), Thr(1)) or a second threshold value Th2 (Thb(2), Thg(2), Thr(2)) stored in the EEPROM 104. If the light intensity Lr of R is equal to or greater than the light intensity Thr(1) of the first threshold value Th1, the light intensity Lg of G is equal to or greater than the light intensity Thg(1) of the first threshold value Th1, and the light intensity Lb of B is equal to or greater than the light intensity Thb(1) of the first threshold value Th1, it is determined that there is snow because the color indicated by the first information is white.

[0056] Under the second condition, it is determined whether there is snow on the ground based on the first information output from the color sensor 91 or the second information output from the snowfall sensor 92. More specifically, it is determined that there is snow on the ground based on the first information output from the color sensor 91, or when the second information indicating that there is snowfall is output from the snowfall sensor 92.

[0057] Under the third condition, it is determined whether there is snow on the ground based on the first information output from the color sensor 91 and the second information output from the snowfall sensor 92. More specifically, if it is determined that there is snow on the ground based on the first information output from the color sensor 91 and the second information indicating that there is snowfall is output from the snowfall sensor 92, it is determined that there is snow on the ground.

[0058] Under the fourth condition, it is determined whether there is snow on the ground based on the first information output from the color sensor 91 or the third information output from the thermistor 93. More specifically, it is determined that there is snow on the ground based on the first information, or if the temperature indicated by the third information is equal to or lower than a predetermined temperature threshold value Tt.

[0059] In the fifth condition, whether there is snow is determined based on the first information output from the color sensor 91 and the third information output from the thermistor 93. More specifically, if it is determined that there is snow based on the first information and the temperature indicated by the third information is equal to or lower than the temperature threshold value Tt, it is determined that there is snow.

[0060] On the other hand, if it is not determined that there is snow under the first to fifth conditions, and the light intensity Lr of R is equal to or less than the light intensity Thr(2) of the second threshold value Th2, the light intensity Lg of G is equal to or less than the light intensity Thg(2) of the second threshold value Th2, and the light intensity Lb of B is equal to or less than the light intensity Thb(2) of the second threshold value Th2, it is determined that there is no snow.

[0061] <First setting process> 5, the first setting process executed by the CPU 101 will be described. In the first setting process, a first threshold value Th1 and a second threshold value Th2 are set, which are referenced when determining whether or not snow is present. The first setting process is started when the CPU 101 executes a program for the first setting process stored in the ROM 102.

[0062] The CPU 101 determines whether an operation to start measurement by the color sensor 91 has been detected via the remote control device 36 (S11). If the CPU 101 determines that an operation via the remote control device 36 has not been detected (S11: NO), the process returns to S11. The CPU 101 continues to wait for an operation on the remote control device 36.

[0063] Here, for example, when there is no snow, the user performs an operation on the remote control device 36 to start measurement by the color sensor 91. Also, when there is snow, the user performs an operation on the remote control device 36 to start measurement by the color sensor 91. When the CPU 101 determines that an operation to start measurement by the color sensor 91 has been detected via the remote control device 36 (S11: YES), the process proceeds to S13.

[0064] CPU 101 turns on color sensor 91 (S13). This causes color sensor 91 to emit light from the light-emitting section and receive reflected light at the light-receiving section. Color sensor 91 detects the light intensities of R, G, and B based on the received light. Color sensor 91 outputs first information indicating the detected light intensities to CPU 101. CPU 101 acquires the first information (S15).

[0065] Next, the user inputs to the remote control device 36 information indicating whether the user has instructed the color sensor 91 to measure when there is no snow or when there is snow.

[0066] When the CPU 101 determines, based on the input to the remote control device 36, that an instruction to perform measurement by the color sensor 91 has been issued in a snowy environment (S17: YES), the CPU 101 determines the light intensity (Thb(1), Thg(1), Thr(1)) of the first threshold value Th1 based on the light intensities (Lr, Lg, Lb) indicated by the first information acquired in S15 (S19). For example, the CPU 101 determines the light intensities (Lr, Lg, Lb) indicated by the first information acquired in S15 as the light intensities (Thb(1), Thg(1), Thr(1)) of the first threshold value Th1 without modification. The CPU 101 stores the determined first threshold value Th1 in the EEPROM 104 (S25). The CPU 101 ends the first setting process.

[0067] The method for determining the first threshold value Th1 is not limited to the above. For example, CPU 101 may determine the light intensities Thb(1), Thg(1), and Thr(1) of the first threshold value Th1 by subtracting a predetermined value from each of the values ​​of Lr, Lg, and Lb obtained in S15. Alternatively, CPU 101 may determine the light intensities Thb(1), Thg(1), and Thr(1) of the first threshold value Th1 by subtracting a predetermined percentage (e.g., 25%) from each of the values ​​of Lr, Lg, and Lb obtained in S15. Alternatively, CPU 101 may determine the light intensities Thb(1), Thg(1), and Thr(1) of the first threshold value Th1 by subtracting a first percentage (e.g., 25%) from each of the values ​​of Lr and Lg obtained in S15 and subtracting a second percentage (e.g., 10%) from the value of Lb obtained in S15.

[0068] On the other hand, when the CPU 101 determines, based on the input to the remote control device 36, that an instruction to perform measurement by the color sensor 91 has been issued in a state where there is no snow (S17: NO), the CPU 101 determines the light intensity (Thb(2), Thg(2), Thr(2)) of the second threshold value Th2 based on the light intensities (Lr, Lg, Lb) indicated by the first information acquired in S15 (S21). For example, the CPU 101 determines the light intensities (Lr, Lg, Lb) indicated by the first information acquired in S15 as the light intensities (Thb(2), Thg(2), Thr(2)) of the second threshold value Th2 without any change. The CPU 101 stores the determined second threshold value Th2 in the EEPROM 104 (S25). The CPU 101 ends the first setting process.

[0069] The method for determining the second threshold value Th2 is not limited to the above. For example, CPU 101 may determine the light intensities Thb(2), Thg(2), and Thr(2) of the second threshold value Th2 by adding a predetermined value to each of the values ​​of Lr, Lg, and Lb acquired in S15. Alternatively, CPU 101 may determine the second threshold value Th2(Thb(2), Thg(2), and Thr(2)) by adding a predetermined percentage (e.g., 25%) to each of the values ​​of Lr, Lg, and Lb acquired in S15. Alternatively, CPU 101 may determine the second threshold value Th2(Thb(2), Thg(2), and Thr(2)) by adding a first percentage (e.g., 25%) to each of the values ​​of Lr and Lg acquired in S15 and adding a second percentage (e.g., 10%) to the value of Lb acquired in S15.

[0070] <Second setting process> The second setting process executed by the CPU 101 will be described with reference to Fig. 6. In the second setting process, determination conditions (first to fifth conditions) are set. The second setting process is started by the CPU 101 executing a program for the second setting process stored in the ROM 102.

[0071] The CPU 101 determines whether an operation to select any one of the first to fifth conditions as a snow accumulation determination condition has been detected via the remote control device 36 (S41). When the CPU 101 determines that an operation via the remote control device 36 has not been detected (S41: NO), the CPU 101 returns the process to S41. The CPU 101 continues to wait for an operation on the remote control device 36.

[0072] Here, the user performs an operation on the remote control device 36 to select one of the first to fifth conditions. When the CPU 101 determines that an operation to select one of the first to fifth conditions has been detected via the remote control device 36 (S41: YES), the CPU 101 acquires the detected condition. The CPU 101 stores the detected condition in the EEPROM 104 as a snow accumulation determination condition (S43). The CPU 101 ends the second setting process.

[0073] <Main processing> 7, the main processing executed by the CPU 101 will be described. The main processing starts when the CPU 101 executes a main processing program stored in the ROM 102.

[0074] The CPU 101 determines whether an operation to turn on the operation switch 36A of the remote control device 36 has been detected (S51). If the CPU 101 has not detected an operation to turn on the operation switch 36A (S51: NO), the process returns to S51. The CPU 101 continues to wait for an operation to turn on the operation switch 36A.

[0075] When the CPU 101 detects an operation to turn on the operation switch 36A (S51: YES), it turns on the lighting device 90 (S53). As a result, the irradiation area 6A of the snow melting target area 6 is illuminated with light, and the brightness of the irradiation area 6A is maintained. The CPU 101 also turns on each sensor of the sensor unit 9A (color sensor 91, snowfall sensor 92, thermistor 93) (S53). As a result, the color sensor 91 emits light from the light-emitting section and receives reflected light from the light-receiving section. The color sensor 91 detects the light intensities of R, G, and B based on the received light. The color sensor 91 outputs first information indicating the detected light intensities of R, G, and B to the CPU 101. The snowfall sensor 92 also heats the heater of the electrode sensor. When the temperature measured by the temperature sensor is equal to or lower than a predetermined temperature and the electrode sensor detects moisture, the snowfall sensor 92 outputs second information indicating that snow is falling to the CPU 101. The thermistor 93 also detects the temperature of the snow melting target area 6. The thermistor 93 outputs third information indicating the detected temperature to the CPU 101.

[0076] The CPU 101 acquires first information output from the color sensor 91 (S55). The CPU 101 acquires second information output from the snowfall sensor 92 (S57). The CPU 101 acquires third information output from the thermistor 93 (S59).

[0077] The CPU 101 reads out the determination conditions stored in the EEPROM 104 in S43 (see FIG. 6) of the second setting process. The CPU 101 also reads out the first threshold value Th1 and the second threshold value Th2 stored in the EEPROM 104 in S19 and S21 (see FIG. 5) of the first setting process.

[0078] The CPU 101 determines whether there is snow based on the read-out determination conditions (S61). If the CPU 101 determines that there is snow (S63: YES), it starts snow melting operation (S65). This heats the snow melting target area 6 on the road surface, melting the snow. The CPU 101 proceeds to S71. On the other hand, if the CPU 101 does not determine that there is snow (S63: NO), it proceeds to S67.

[0079] The CPU 101 determines whether there is snow based on the read-out determination conditions (S67). If the CPU 101 determines that there is no snow (S67: YES), it stops the snow melting operation (S69). The CPU 101 proceeds to S71. On the other hand, if the CPU 101 does not determine that there is no snow (S67: NO), it proceeds to S71.

[0080] The CPU 101 determines whether or not an operation to turn off the operation switch 36A of the remote control device 36 has been detected (S71). If the CPU 101 has not detected an operation to turn off the operation switch 36A (S71: NO), the process returns to S55 and the process is repeated.

[0081] For example, if the light intensity indicated by the first information is equal to or greater than the first threshold Th1, it is determined that there is snow, and snow melting operation is started (S63: YES → S65), the snow begins to melt. Even if the light intensity indicated by the first information becomes less than the first threshold Th1 (S63: NO), the light intensity indicated by the first information will not become less than the second threshold Th2 unless the snow has completely melted. In this case, it is not determined that there is no snow (S67: NO), and the snow melting operation is not stopped. Thereafter, if the light intensity indicated by the first information becomes less than the second threshold Th2 as the snow melts, and it is determined that there is no snow (S63: NO → S67: YES), the snow melting operation started in S65 is stopped (S69).

[0082] When the CPU 101 detects an operation to turn off the operation switch 36A (S71: YES), the CPU 101 turns off the lighting device 90 and the sensors of the sensor unit 9A (the color sensor 91, the snow sensor 92, and thermistor 93) (S73). The CPU 101 ends the main processing.

[0083] <Actions and Effects of This Embodiment> The snow melting device 1 measures the R, G, and B light intensities of light reflected from the road surface using a color sensor 91, and determines whether there is snow on the road surface based on the measurement results. In this case, it is possible to determine whether there is snow on the road surface without using a camera or a controller required for image analysis. Therefore, the snow melting device 1 can inexpensively realize a configuration that heats and melts snow. Furthermore, the snow melting device 1 acquires first information indicating the R, G, and B light intensities of the reflected light from the color sensor 91 while the road surface is illuminated by the lighting device 90. In this case, the snow melting device 1 can accurately determine whether there is snow on the road surface.

[0084] When determining whether or not there is snow based on the first information, the snow melting device 1 determines that there is snow if the color indicated by the first information is white. In this case, the snow melting device 1 can determine whether or not there is snow on the road surface based on the color.

[0085] When determining whether or not there is snow based on the first information, if the light intensities of R, G, and B indicated by the first information are all equal to or greater than the first threshold value Th, the snow melting device 1 determines that there is snow because the color identified by the first information is white. In this case, the snow melting device 1 can determine the snow on the road surface by color based on the light intensities of R, G, and B in the reflected light.

[0086] The snow melting device 1 acquires first information indicating the R, G, and B light intensities of the reflected light when the reference portion Rp is provided on the road surface. In this case, the snow melting device 1 can increase the color contrast between when there is snow and when there is not snow at the location of the reference portion Rp on the road surface. Therefore, the snow melting device 1 can accurately determine whether there is snow.

[0087] The snow melting device 1 sets a first threshold value Th1 for determining whether snow is present based on the first information acquired when the reference portion Rp is provided and there is snow (S19). The snow melting device 1 also sets a second threshold value Th2 for determining whether snow is absent based on the first information acquired when the reference portion Rp is provided and there is no snow (S21). When determining whether snow is present based on the first information, the snow melting device 1 determines whether snow is present using the first threshold value Th1 (S63) and whether snow is absent using the second threshold value Th2 (S67). This allows the snow melting device 1 to accurately determine whether snow is present and whether snow is absent.

[0088] In response to a user's operation, the snow melting device 1 acquires first information from the color sensor 91 (S15), determines the first threshold value Th1 or the second threshold value Th2, and stores it in the EEPROM 104 (S19, S21). In this case, the user can set the first threshold value Th1 with high accuracy by specifying a time when there is snow and having the snow melting device acquire the first information. Also, the user can set the second threshold value Th2 with high accuracy by specifying a time when there is no snow and having the snow melting device acquire the first information.

[0089] Under the second or third condition, the snow melting device 1 determines whether there is snow accumulation based on the first information acquired from the color sensor 91 and the second information acquired from the snowfall sensor 92. Under the fourth or fifth condition, the snow melting device 1 determines whether there is snow accumulation based on the first information acquired from the color sensor 91 and the third information acquired from the thermistor 93. In these cases, the snow melting device 1 can determine whether there is snow accumulation with better accuracy than when the determination is based only on the first information.

[0090] The snow melting device 1 determines whether there is snow accumulation based on any one of the first to fifth conditions selected by the user. In this case, the presence of snow accumulation is determined based on the information set by the user to be valid among the first information output from the color sensor 91, the second information output from the snowfall sensor 92, and the third information output from the thermistor 93. Therefore, by setting which of the first to fifth conditions to be valid depending on the environment in which the snow melting device 1 is used, the user can improve the accuracy of the snow accumulation determination regardless of the environment in which the snow melting device 1 is used.

[0091] The snow melting device 1 has a lighting support part 900 that can adjust the height of the lighting device 90. By adjusting the height of the lighting device 90, the user can maintain the brightness of the road surface illuminated by the lighting device 90 regardless of the environment or time of day in which the snow melting device 1 is used. In this case, the snow melting device 1 can accurately determine the amount of snow accumulated regardless of the environment or time of day in which it is used.

[0092] The snow melting device 1 uses the color sensor 91, which is cheaper than a camera, and can therefore inexpensively realize a configuration for heating and melting accumulated snow.

[0093] <Modification> The present invention is not limited to the above embodiment, and various modifications are possible. The color sensor 91 outputs first information indicating the light intensities of R, G, and B in the reflected light. In contrast, the color sensor 91 may output first information indicating the light intensities of wavelength ranges different from R, G, and B. The snow melting device 1 may determine that the color indicated by the first signal is white if the ratio of the light intensities of the R, G, and B components indicated by the first information satisfies a predetermined condition.

[0094] The method for determining the first threshold Th1 in S19 and the method for determining the second threshold Th2 in S21 may be changeable by the user. For example, in S19, the first threshold Th1 may be determined by adding a predetermined value to each of the values ​​of Lr, Lg, and Lb. For example, in S21, the second threshold Th2 may be determined by subtracting a predetermined value from each of the values ​​of Lr, Lg, and Lb. For example, the predetermined value added or subtracted to determine the first threshold Th1 in S19 and the predetermined value added or subtracted to determine the second threshold Th2 in S21 may be set by the user.

[0095] The color of the reference portion Rp is not limited to black and may be other colors. Multiple reference portions Rp of different colors may be used. The first threshold value Th1 and the second threshold value Th2 may be set for each color of the reference portion Rp. The height of the lighting device 90 may be fixed. In this case, the illuminance of the lighting device 90 may be changed depending on the surrounding environment.

[0096] 8 shows the first setting process in the modified example. The first setting process in the modified example differs from the first setting process in the above embodiment in that the process of S23 is further executed after the process of S21.

[0097] 8, after determining the second threshold value Th2 in S21, the CPU 101 determines the first threshold value Th1 based on the determined second threshold value Th2 (S23). Specifically, for example, the CPU 101 determines the light intensities Thb(1), Thg(1), and Thr(1) of the first threshold value Th1 by adding a predetermined value to each of the light intensities Thb(2), Thg(2), and Thr(2) of the second threshold value Th2. The CPU 101 stores the determined first threshold value Th1 in the EEPROM 104 (S25). The CPU 101 ends the first setting process.

[0098] In this case, the user does not need to perform a procedure to determine the first threshold value Th1, and therefore the snow melting device 1 can facilitate the user's setting of the first threshold value Th1.

[0099] <Other> The CPU 101 that performs the processing of S53 is an example of the "irradiation means" of the present invention. The CPU 101 that performs the processing of S55 is an example of the "first acquisition means" of the present invention. The CPU 101 that performs the processing of S61, S63, and S67 is an example of the "determination means" of the present invention. The CPU 101 that performs the processing of S65 is an example of the "heating means" of the present invention. The CPU 101 that performs the processing of S19, S21, and S23 is an example of the "first setting means" of the present invention. The CPU 101 that performs the processing of S15 is an example of the "designation acquisition means" of the present invention. The CPU 101 that performs the processing of S57 is an example of the "second acquisition means" of the present invention. The CPU 101 that performs the processing of S59 is an example of the "third acquisition means" of the present invention. The CPU 101 that performs the processing of S43 is an example of the "second setting means" of the present invention. The illumination support unit 900 is an example of the "change unit" of the present invention. The EEPROM 104 is an example of the "storage unit" of the present invention. The illumination device 90 is an example of the "light source" of the present invention. [Explanation of symbols]

[0100] 1:Snow melting device 90: Lighting equipment 91: Color sensor 92: Snowfall sensor 93: Thermistor 101: CPU 104: EEPROM 900: Lighting Support Department Rp

Claims

1. an illumination means for controlling the light source to illuminate the road surface; a first acquiring means for acquiring first information indicating the intensity of light reflected from the road surface illuminated by the light source controlled by the illuminating means for each wavelength; a determination means for determining whether or not snow is present on the road surface based on the first information acquired by the first acquisition means; a heating means for heating the road surface when the determining means determines that snow is present on the road surface; A snow melting device comprising:

2. The determination means The snow melting device according to claim 1, wherein when the color identified by the first information is white, it is determined that snow is present on the road surface.

3. The determination means A snow melting device as described in claim 2, characterized in that if the intensities of the wavelengths of R, G, and B indicated by the first information are all equal to or greater than a first threshold value stored in a memory unit, the color identified by the first information is determined to be white.

4. a reference portion made of a standard color is provided on at least a part of the road surface; The first acquisition means The snow melting device according to claim 1, characterized in that the first information indicating the intensity of the reflected light for each wavelength in a state in which the reference portion is provided on the road surface is acquired.

5. a reference portion made of a standard color is provided on at least a part of the road surface; The snow melting device described in claim 3, characterized in that it is provided with a first setting means that determines the first threshold value based on the first information indicating the intensity of each wavelength of the reflected light when the reference unit is provided and there is snow accumulation, and stores and sets the first threshold value in the memory unit.

6. a designation acquisition means for acquiring the first information indicating the intensity of the reflected light for each wavelength from the road surface illuminated by the light source in response to an instruction from a user, The first setting means The snow melting device according to claim 5, wherein the first threshold value is determined based on the first information acquired by the designation acquisition means, and is stored and set in the storage unit.

7. a reference portion made of a standard color is provided on at least a part of the road surface; a first setting means for determining a second threshold value for determining that there is no snow based on the first information indicating the intensity of each wavelength of the reflected light when the reference portion is provided and there is no snow, and for storing and setting the second threshold value in a storage unit; The determination means A snow melting device as described in claim 1, characterized in that if the intensities of the wavelengths of R, G, and B indicated by the first information are all below the second threshold value stored in the memory unit, it is determined that there is no snow on the road surface.

8. a designation acquisition means for acquiring the first information indicating the intensity of the reflected light for each wavelength from the road surface illuminated by the light source in response to an instruction from a user, The first setting means The snow melting device according to claim 7, wherein the second threshold value is determined based on the first information acquired by the designation acquisition means, and is stored and set in the storage unit.

9. The first setting means The snow melting device described in claim 8, characterized in that a first threshold value for determining that snow is present on the road surface is further determined based on the second threshold value, and the first threshold value and the second threshold value are stored and set in the memory unit.

10. The snowfall sensor further includes a second acquisition means for acquiring second information output from the snowfall sensor, The determination means The snow melting device according to claim 1, characterized in that it determines whether there is snow on the road surface based on the first information acquired by the first acquisition means and the second information acquired by the second acquisition means.

11. The vehicle further includes a third acquisition means for acquiring third information output from a thermistor capable of measuring the temperature of the road surface, The determination means The snow melting device according to claim 1, characterized in that it determines whether there is snow on the road surface based on the first information acquired by the first acquisition means and the third information acquired by the third acquisition means.

12. a second acquiring means for acquiring second information output from the snowfall sensor; a third acquisition means for acquiring third information output from a thermistor capable of measuring the temperature of the road surface; a second setting means for setting which of the first information acquired by the first acquisition means, the second information acquired by the second acquisition means, and the third information acquired by the third acquisition means is to be valid; Further provided with The determination means The snow melting device according to claim 1, characterized in that it determines whether there is snow on the road surface based on the information set as valid by the second setting means among the first information, the second information, and the third information.

13. the light source is a lighting device that maintains the brightness of the road surface, The snow melting device according to claim 1, further comprising a changer that can change the distance between the lighting device and the road surface.

14. The first acquisition means The snow melting device according to claim 1 , wherein the first information is acquired from a color sensor.

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