Remote Control System

Abstract

To make it possible to inform an operator of a change in radio wave intensity in addition to radio wave intensity received by a vehicle remotely controlled.SOLUTION: A communication device 14 is for manipulating a vehicle by transmitting and receiving radio waves to / from the vehicle. The communication device 14 includes a display unit 21 that displays information. The display unit 21 can display a first image 22 representing a first radio wave intensity, which is a radio wave intensity of a radio wave currently being received by the vehicle, and a second image 32 representing information about a change in the first radio wave intensity.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a remote control system that enables an operator to remotely control a work machine from a remote location, and more particularly to an improved remote control system that enables the operator to grasp the communication status of the work machine. [Background technology]

[0002] In recent years, a system has been developed that performs work by remotely controlling a work machine at a work site, as disclosed in Patent Document 1. In the remote control system of Patent Document 1, an operator remotely controls the machine by riding in a remote control device manufactured to be similar to the cockpit of an actual machine. The control device is equipped with a large monitor in front of the operator, and the operator can see the same field of view as when riding in an actual vehicle, allowing the operator to operate the work machine with the feeling of riding in the actual vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-200660 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the operator cannot grasp the communication status of the work machine that is being remotely operated. When the work machine moves, the radio wave strength of the radio waves received by the work machine changes depending on the location. Therefore, if the work machine moves to a place in the work area where the radio waves are unstable, there is a risk of communication being cut off. However, since the operator cannot grasp the communication status of the work machine, he / she cannot predict communication cut off. As a result, unexpected communication cut off occurs, and work is interrupted. Alternatively, delays in control of the work machine and instability in the images transmitted from the work machine to the remote device operated by the operator occur, which are factors that cause work delays.

[0005] In order to avoid the above-mentioned interruptions and delays in work, a means for grasping the changing communication conditions of a work machine that is working while moving has been desired.

[0006] The present invention has been made to solve the above-mentioned problems, and has an object to provide a means for understanding the communication status of a remotely operated work machine. [Means for solving the problem]

[0007] The communication device of the present invention is a communication device that transmits and receives radio waves between a vehicle and the vehicle to remotely operate the vehicle, and is characterized in that the communication device is equipped with a display device that displays information, and the display device is capable of displaying a first image that represents a first radio wave intensity, which is the radio wave intensity of the radio waves currently being received by the vehicle, and a second image that represents information regarding changes in the first radio wave intensity.

[0008] According to the communication device of the present invention, it is possible to notify the driver of the intensity of radio waves received by a remotely operated vehicle as well as any changes in the intensity of radio waves.

[0009] In addition, in the communication device of the present invention, it is preferable that the information regarding the change in the first radio wave intensity is the change in the first radio wave intensity relative to the second radio wave intensity, which is the radio wave intensity at a point in time a predetermined time before the current point in time, and the second image includes a third image indicating that the first radio wave intensity is greater than or equal to the second radio wave intensity, and a fourth image indicating that the first radio wave intensity is less than the second radio wave intensity.

[0010] According to the communication device of the present invention, the driver can be informed by the second image including the third image and the fourth image whether the radio wave strength received by the remotely operated vehicle is getting stronger or weaker. In particular, the driver who remotely operates the vehicle needs to concentrate on the remote operation, but even in such a situation, the driver can easily grasp the change in radio wave strength by glancing at the second image.

[0011] In addition, it is preferable that the communication device of the present invention includes a position identification unit that identifies the position of the vehicle, and a memory unit that stores information including a history of one or more radio wave intensities received by the vehicle in association with position information of each radio wave strength, and the display unit is capable of displaying a fifth image that displays the radio wave intensities included in the history in association with the corresponding position information.

[0012] The communication device according to the present invention allows the operator to know the radio wave strength of a specific location within the work area where the remotely controlled vehicle is working whenever the operator wants to know it. Therefore, the operator can select a work location with good communication conditions to work, or work under the assumption that the communication conditions are poor.

[0013] In the communication device according to the present invention, the fifth image is preferably displayed on a map showing an area in which the vehicle is traveling.

[0014] According to the communication device of the present invention, the radio wave strength of the locations where the vehicle has traveled within the vehicle driving area is displayed superimposed on a map showing the vehicle driving area, allowing the driver to easily understand the radio wave conditions in the vehicle driving area. [Brief description of the drawings]

[0015] [Figure 1] 1 is a schematic diagram of a remote control system according to an embodiment of the present invention; [Diagram 2] 2A and 2B show a first image and a second image displayed on the communication device of FIG. 1. [Diagram 3] 2A and 2B show a first image and a second image displayed on the communication device of FIG. 1. [Figure 4] 2 is a first image displayed on the communication device of FIG. 1; [Diagram 5] 5 is a fifth image displayed on the communication device of FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] A remote control system 100 according to an embodiment of the present invention will be described with reference to FIG. 1. The remote control system 100 includes a remote control device 10 that allows an operator to remotely control a vehicle, and a transmitting / receiving device 80 that is installed in a vehicle located away from the remote control device 10. In the following embodiment, the vehicle will be described as a work machine, which is an example of a vehicle. The work machine is, for example, a power shovel, a crane, or a dump truck. The remote control system 100 can be applied to vehicles other than work machines without limiting the type of vehicle. The remote control system 100 can be applied to, for example, passenger cars, buses, trucks, motorcycles, and the like.

[0017] Next, the remote control device 10 and the transmitting / receiving device 80 mounted on the work machine will be described. The remote control device 10 includes a processing unit 11, a display processing unit 12, a monitor 13, and a communication unit 14. In addition, the remote control device 10 includes a seat, an operating lever, and switches (not shown), and the monitor 13 is disposed in front of the seat where the operator sits. The processing unit 11 also includes a CPU and a memory (not shown). The processing unit 11 and the display processing unit 12, and the processing unit 11 and the communication unit 14 are connected by LAN cables. The display processing unit 12 and the monitor 13 are connected by an HDMI cable.

[0018] The remotely operated work machine is provided with a transmitting / receiving device 80. In addition, a camera (not shown) that captures the front view is attached to the work machine, and the image captured by the camera is transmitted to the remote control device 10 via the transmitting / receiving device 80. Transmission and reception is performed between the remote control device 10 and the transmitting / receiving device 80 via wireless communication. The type of wireless communication can be selected appropriately, and for example, WiFi communication or radio waves for mobile phone communication are used. The transmitted image is received by the communication device 14 installed in the remote control device 10 and displayed on the monitor 13 via the arithmetic processing device 11 and the display processing device 12. While viewing the image displayed on the monitor 13, the operator operates the operating levers and switches provided on the remote control device 10 in the same way as when he is on board the work machine. The arithmetic processing device 11 detects the type and amount of operation of the device operated by the operator, and transmits a control signal to the work machine via the communication device 14.

[0019] The control signal is received by the transmitting / receiving device 80, and the work machine is remotely operated. The transmitting / receiving device 80 can also recognize the strength of the received radio waves, and transmits information about the strength of the received radio waves to the remote control device 10 in real time at regular time intervals. The remote control device 10 stores the transmitted information about the strength of the received radio waves in the storage unit 61 and displays it on the first image. Information about the strength of the received radio waves can be received at regular time intervals, but if the information cannot be received due to a decrease in radio wave strength or the like and there is a loss in the received information, the radio wave strength at the loss time for each regular time interval is automatically stored as being less than a predetermined minimum radio wave strength.

[0020] Next, the first image 22 and the second image 32 displayed on the communication device 14 will be described with reference to Fig. 2. The communication device 14 has a display unit 21, on which information including the radio wave intensity received by the transmission / reception device 80 is displayed. The display unit 21 is selected from displays such as a liquid crystal screen, an organic EL screen, or a display device such as an LED display device in which a plurality of LEDs are combined. The display unit 21 may select a part of the display surface of the monitor 13 as the display device.

[0021] The first image 22 represents a first radio wave intensity, which is the intensity of radio waves currently being received by the work machine. The first image 22 includes a first image element 23, a second image element 24, a third image element 25, and a fourth image element 26. The radio wave intensity of the received radio waves is divided into four stages ranging from a predetermined minimum radio wave intensity that can be received to a predetermined maximum radio wave intensity, and each stage is displayed using the first image element 23, the second image element 24, the third image element 25, and the fourth image element 26. Each of the first image element 23 to the fourth image element 26 is displayed or hidden according to each stage.

[0022] The first image element 23, the second image element 24, the third image element 25, and the fourth image element 26 are each a rectangle formed with a slightly different length. Each of the first image element 23 to the fourth image element 26 includes a first long side 27, a second long side 28, a first short side 29, and a second short side 30, and is arranged with the longitudinal direction in FIG. 2. The first long side 27 and the second long side 28 are parallel to each other, and the second long side 28 is formed slightly longer than the first long side 27. The first short side 29 is arranged horizontally and downward, and the first long side 27 and the second long side 28 are arranged vertically with the lower end of the first long side 27 overlapping the left end of the first short side 29 and the lower end of the second long side 28 overlapping the right end of the first short side 29. Furthermore, above them, the second short side 30 is disposed with its left end overlapping the upper end of the first long side 27 and its right end overlapping the upper end of the second long side 28. The second long side 28 on the right side is formed slightly longer than the first long side 27 on the left side, so each second short side 30 is formed slanting upward to the right.

[0023] As shown in FIG. 2, the first image element 23 to the fourth image element 26 are arranged adjacent to each other from left to right in the order of the shortest first image element 23 to the longest fourth image element 26, with a small constant gap between them, in the longitudinal direction of the first image element 23 to the fourth image element 26. The first short sides 29 on the lower side of each are arranged to be located on the same straight line. Also, the second short sides 30 formed on the upper side of each are arranged to be located on the same straight line. The length of the first image element 23 to the fourth image element 26 is longer toward the fourth image element 26 at the right end, and the upper end side of the first image element 23 to the fourth image element 26 is formed to be slanted upward to the right. Therefore, the first image is configured so that the pilot can intuitively understand at a glance that the right side indicates a state in which the radio wave intensity is stronger.

[0024] Of the four signal strength levels, in the first level, which is the weakest, only the first image element 23 is displayed. In the second level, which is slightly stronger than the first level, the first image element 23 and the second image element 24 are displayed. In the third level, which is slightly stronger than the second level, the first image element 23, the second image element 24, and the third image element 25 are displayed. In the fourth level, which is even stronger than the third level, all of the first image element 23 to the fourth image element 26 are displayed. In this way, the first image 22 is configured so that the number of displayed image elements increases in proportion to the signal strength, so the pilot can intuitively know the current signal strength at just one glance at the first image 22.

[0025] In the above description, the radio wave intensity is divided into four stages, but it may be divided into stages other than four. For example, it may be divided into two stages, three stages, or five or more stages. In this case, the number of first image elements 23 and the like included in the first image is formed according to the number of stages. In addition, in the above description, a configuration has been described in which the first image element 23, which means the first stage, which is the lowest stage, is displayed continuously up to the current stage, for example, the third image element 25, but it is also possible to display only the current stage without displaying the lowest stage below the current one. For example, if the current radio wave intensity is the third stage, only the third image element 25 may be displayed.

[0026] The first image element 23 to the fourth image element 26 are formed in a color different from the background. It is preferable that the color is different from the background color so that the first image element 23 and the like can be clearly recognized. For example, the first image element 23 and the like are white and the background is black. Alternatively, the color scheme may be reversed. The colors of each element can be selected arbitrarily from white, black, blue, red, yellow, green, gray, intermediate colors, etc.

[0027] Alternatively, in addition to changing the respective colors, the same color may be changed in brightness. Furthermore, the color and brightness may be changed together. As with the brightness, the saturation may be changed. Furthermore, the first image elements 23, etc. may be formed in a display pattern different from that of the background. For example, one of them may be solid and the other may be a hatched pattern, a dot pattern, etc. Furthermore, the first image elements 23, etc. and the background may be different in color and pattern.

[0028] Also, the colors of the first image element 23 to the fourth image element 26 may not be the same, but may be different from each other. Or, they may have different brightness, saturation, and display pattern. It is sufficient that the first image element 23 to the fourth image element 26 are clearly recognizable from the background and from each other. Furthermore, when displaying the first image in a state where the radio wave intensity is weak, it is possible to form it in a state where it stands out more than the others. For example, only the first image element 23, or the first image element 23 and the second image element 24, can be red, yellow, or the like. Or, they may be displayed in a flashing manner. The first image element 23 to the fourth image element 26 may have a contour line that follows the outer shape of part or all of them.

[0029] Next, the second image 32 showing information on the change in radio wave intensity received by the work machine will be described. The radio wave intensity of radio waves received by a vehicle such as a work machine moving within a travel area varies greatly depending on the distance from the antenna of the work machine, the size and presence of structures around the work machine, and the presence or absence of radio waves in a frequency band close to the frequency used by the remote control device 10. The second image 32 shows the change in the first radio wave intensity relative to the second radio wave intensity, which is the radio wave intensity at a time a predetermined time before the present time. In other words, the operator can know from the second image 32 whether the first radio wave intensity, which is the radio wave intensity at the present time, is equal to or greater than the time at a time before the predetermined time, or whether it is less than that. The second image 32 includes a third image 33 showing the former and a fourth image 34 showing the latter.

[0030] The predetermined time is initially set as a predetermined time before the current time point of the first radio wave strength, which is the time point of the second radio wave strength that is the comparison standard. The predetermined time can be set arbitrarily. It may be set according to the type of vehicle. For example, for a work machine that moves slowly and does not travel long distances, the predetermined time can be set to 10 seconds, 15 seconds, 30 seconds, 45 seconds, 1 minute, etc. For a passenger car or the like that moves quickly and travels long distances, the predetermined time can be set to 1 second, 3 seconds, 5 seconds, 10 seconds, etc.

[0031] In FIG. 2, the third image 33 is shown adjacent to the upper side of the first image 22. The third image 33 is a display indicating that the first radio wave intensity is equal to or greater than the second radio wave intensity, which is the radio wave intensity at a time a predetermined time before the present time. The third image 33 is displayed, for example, when the display changes from only the first image element 23 to the second image element 24, or the second image element 24 and the third image element 25, or when there is no change in the displayed first image. When the third image 33 is displayed, the radio wave intensity is the same or stronger, and the pilot can recognize that the situation is such that communication disconnection is unlikely to occur.

[0032] 2 is a schematic diagram showing a power shovel climbing a slope. The third image 33 includes a drive unit 331 including a crawler, a riding unit 332 arranged on the drive unit 331, and an attachment unit 333 such as a power shovel arranged in front of the riding unit 332, and is formed with the front direction facing diagonally upward as if the power shovel is climbing up a slope.

[0033] The third image 33 may have any shape. For example, it may be an upward triangle, an upward or diagonally upward or rightward arrow, a circle, a square, or other shape. The third image 33 may be formed in a specific color, pattern, or both. Furthermore, the third image 33 may be displayed in a flashing manner, either alone, together with a part of the first image, or together with the entire first image.

[0034] In Fig. 3, a fourth image 34 is shown adjacent to the upper side of the first image 22. The third image 33 is a display indicating that the first radio wave intensity is less than the second radio wave intensity with respect to the second radio wave intensity. The third image 33 is displayed, for example, when the display changes from a state in which the first image element 23 to the third image element 25 are displayed to a state in which only the first image element 23 is displayed. When the fourth image 34 is displayed, the radio wave intensity has changed to be weaker, and the pilot can recognize that this is a situation in which a communication failure such as a communication cutoff may occur.

[0035] 3 is a schematic diagram showing a state in which a power shovel is descending a slope. The fourth image 34 includes a drive unit 341 including a crawler, a riding unit 342 arranged on the drive unit 341, and an attachment unit 343 such as a power shovel arranged in front of the riding unit 342, and is formed so that the front direction faces diagonally downward as if the power shovel is descending a slope.

[0036] The fourth image 34 may have any shape. For example, any display that can be distinguished from the third image 33, such as a downward triangle, an arrow pointing downward or diagonally downward or to the left, and a figure such as a circle or a square, may be used. The fourth image 34 may be formed in a specific color, pattern, or both. It may be in a conspicuous color such as red or yellow so that it is easily recognized by the pilot. Furthermore, the fourth image 34 may be displayed in a flashing manner, either alone, together with a part of the first image, or together with the entire first image.

[0037] In the above, a case has been described in which the second image 32 includes the third image 33 and the fourth image 34, but the second image 32 may be configured to include only the fourth image 34 without including the third image 33. In other words, the second image 32 showing information related to changes in radio wave intensity received by the work machine may be only the third image 33 showing that the first radio wave intensity is less than the second radio wave intensity, relative to the second radio wave intensity. In this case, the display can be simplified, improving visibility for the operator.

[0038] Next, referring to FIG. 4, a description will be given of a state in which the radio wave intensity is less than a predetermined value, that is, a radio wave no-detection state in which radio waves are not detected and no radio waves are received. FIG. 4 shows a fifth image element 31 formed in an x ​​shape of intersecting straight lines superimposed on the first image 22. A state in which the radio wave intensity is less than a predetermined value means that the radio wave intensity received by the transceiver 80 of the work machine is less than a predetermined minimum reception intensity, there is some problem with the remote control device 10 or the transceiver 80 of the work machine, and radio waves cannot be transmitted or received normally, etc. Because of the radio wave no-detection state, the first image element 23 to the fourth image element 26, the third image 33, and the fourth image 34 are not displayed. Note that the display shape of the fifth image element 31 is not limited to this. Also, the x shape may be displayed without being superimposed on the first image 22.

[0039] Next, a fifth image which displays radio wave intensity in association with corresponding position information will be described. The communication device 14 has a position identification unit 51 which identifies the position of the work machine, and a memory unit 61 which associates and stores the position of the work machine identified by the position identification unit 51 and information relating to the radio wave intensity at that position. Meanwhile, the transmission / reception device 80 mounted on the work machine has a position detection device 81. Position information of the work machine is detected by the position detection device 81 and transmitted by the transmission / reception device 80.

[0040] The transmitted work machine position information is received by communication device 14 and sent to position identification unit 51, where the position of the work machine is identified. Thereafter, the work machine position information and information relating to radio wave strength at that position are associated with each other and stored in memory unit 61. The position information stored in memory unit 61 and information relating to radio wave strength at that position are stored as multiple sets as a history of both, including the current time.

[0041] The above will be further explained with reference to Fig. 5. Fig. 5 shows a fifth image 41. In the fifth image 41, the position of a sixth image element 43 in an area 42 is the location of the current vehicle, i.e., the work machine. A map showing the area 42 is displayed based on the position of the work machine. The displayed area 42 is a map of the surroundings of the work machine including topographical data, and is stored as map data in the memory unit 61 of the communication device 14. The range of the displayed map area is initially set. In the case of a work machine with a short travel distance, a narrow area range on the map is displayed on the display unit 21. Also, in the case of a vehicle with a long travel distance or a wide travel range, such as a passenger car, a wide area range on the map is displayed.

[0042] The seventh image element 44 displayed in the area 42 is an antenna that transmits and receives radio waves to communicate with the work machine. The antenna is a base station that relays communication between the remote control device 10 and the transmitting / receiving device 80, and communicates with the remote control device 10 by wire or wirelessly. Radio wave strength A45 to radio wave strength C47 are radio wave strengths at points A to C where the work machine has traveled up to now. Since point A is close to the antenna, the radio wave strength display for point A shows three lines from the first image element 23 to the third image element 25 in the first image 22. Since point C is far from the antenna, the radio wave strength of point C shows only one line from the first image element 23 in the first image 22. Since the distance from point B to the antenna is midway between points A and C, the radio wave strength of point B shows two lines from the first image element 23 to the second image element 24 in the first image 22.

[0043] In this way, the radio wave strength in the location where the work machine has traveled is displayed at the corresponding position within the area 42 of the fifth image 41. Therefore, the operator can easily grasp the radio wave strength at each location within the area 42 at once, and can make a driving plan that avoids locations where the possibility of communication cutoff is predicted.

[0044] The range of the display area displayed on the display unit 21 can be changed to a desired range. Furthermore, the range of the displayed area can be automatically changed so that it becomes approximately the same as the area of ​​the moving range, depending on the length of the moving distance of the vehicle or the size of the moving range. For example, if the moving range of the vehicle is narrower than the set display range, the range of the area on the map to be displayed is set small and displayed on the display unit 21 so that only the area of ​​the moving range is displayed.

[0045] On the other hand, when the moving range of the vehicle is wider than the set display range, the area range on the map to be displayed is set larger so that the entire moving range is displayed on the display unit 21. In this way, the entire moving range of the vehicle is automatically and appropriately displayed on the display unit 21, and the radio wave intensity of the place where the vehicle is traveling can be displayed in an easy-to-see manner.

[0046] The points at which the radio wave intensity is displayed in the area 42 of the fifth image can be selected. For example, it is possible to display only points where the radio wave intensity is strong for three or more lines from the first image element 23 to the fourth image element 26 in the first image. It is also possible to display only points where the radio wave intensity is weak for up to two lines from the first image element 23 to the second image element 24 in the first image, or for only one line from the first image element 23.

[0047] In addition, the area 42 of the fifth image can be displayed by coloring the map in multiple parts according to the radio wave intensity. For example, the areas 48a to 48d are colored with reference to the radio wave intensity and the antenna position from point A to point C. The area 48a is an area where the first image element 23 to the fourth image element 26 can be switched to display, the area 48b is an area where the first image element 23 to the third image element 25 can be switched to display, the area 48c is an area where the first image element 23 and the second image element 24 can be switched to display, and the area 48d is an area where only the first image element 23 can be switched to display. The areas 48a to 48d are displayed with different colors, gradations, etc. so that they can be distinguished from each other. The accuracy of the coloring may be improved by increasing the number of points where the radio wave intensity is measured for use in the coloring.

[0048] According to the present invention, in addition to the radio wave intensity of radio waves received by a vehicle remotely operated by a driver, the driver can be notified of any changes in the radio wave intensity. [Explanation of symbols]

[0049] 14 communication device, 21 display unit, 22 first image, 32 second image, 33 third image, 34 fourth image, 51 position identification unit, 61 storage unit, 41 5th image, 42 area.

Claims

1. A communication device that remotely controls a vehicle by transmitting and receiving radio waves to and from the vehicle, the communication device includes a display unit for displaying information; The display unit displays a first image showing first information that is information indicating a degree of possibility of communication disconnection of radio waves currently being received by the vehicle; a second image representing information relating to a change in the first information; A communication device, wherein information regarding the change in the first information represented by the second image is a change status of the first information relative to the second information, which is information indicating the degree of possibility of communication interruption of the radio waves at a predetermined time before the current time, and the first information represents a communication situation in which communication interruption is as unlikely to occur as the second information.

2. A communication device as described in claim 1, wherein the second image includes a third image indicating that the first information is a communication situation in which communication interruptions are equally or more unlikely to occur than the second information.

3. A communication device that remotely controls a vehicle by transmitting and receiving radio waves to and from the vehicle, the communication device includes a display unit for displaying information; The display unit displays a first image showing first information that is information indicating a degree of possibility of communication disconnection of radio waves currently being received by the vehicle; a second image representing information relating to a change in the first information; A communication device, wherein information regarding the change in the first information represented by the second image is a change status of the first information relative to the second information, which is information indicating the degree of possibility of communication interruption of the radio waves at a predetermined time before the current time, and represents that the first information is a communication status in which communication errors are more likely to occur than the second information.

4. A communication device as described in claim 3, wherein the second image includes a fourth image indicating that the first information is a communication situation in which communication errors are more likely to occur than the second information.

5. The communication device includes a position identifying unit that identifies a position of the vehicle; a storage unit that stores information including a history of one or more communication disconnection possibility degrees for radio waves received by the vehicle in association with reception location information of each communication disconnection possibility degree, The communication device according to any one of claims 1 to 4, wherein the display unit is capable of displaying a fifth image that displays the degree of possibility of one or more communication disconnections included in the history in association with corresponding location information.

6. The communication device of claim 5 , wherein the fifth image is displayed on a map showing an area in which the vehicle is traveling.

7. The first information represented by the first image represents a first radio wave intensity which is a radio wave intensity of a radio wave currently being received by the vehicle; 3. The communication device of claim 1 or 2, wherein the information regarding the change in the first information represented by the second image is a change in the first radio wave intensity relative to a second radio wave intensity, which is the radio wave intensity at a predetermined time before the current time, and indicates that the first radio wave intensity is equal to or greater than the second radio wave intensity.

8. The first information represented by the first image represents a first radio wave intensity which is a radio wave intensity of a radio wave currently being received by the vehicle, 5. The communication device of claim 3 or 4, wherein the information regarding the change in the first information represented by the second image is a change in the first radio wave intensity relative to a second radio wave intensity, which is the radio wave intensity at a predetermined time before the current time, and indicates that the first radio wave intensity is less than the second radio wave intensity.

9. A remote control device equipped with a communication device described in any one of claims 1 to 8.

Images