RTG crane and radar device

Abstract

To provide an RTG crane capable of easily improving distance resolution of a radar device, and to provide a radar device.SOLUTION: An RTG crane 10 comprises a radar device 40 of a frequency continuous modulation type for detecting a distance to an object using millimeter waves. A delaying unit 44 is provided for delaying a signal with respect to at least one of a transmission antenna 41 and a reception antenna 42. A delay time according to the delaying unit 44 can shift a distance step of distance resolution in a distance direction. By providing a difference of distance steps of distance resolution using the delaying unit 44 for a transmission antenna 41 and a reception antenna 42 related to another set, with respect to a transmission antenna 41 and a reception antenna 42 related to a certain set, the distance steps of distance resolution can be mutually shifted. As a result thereof, the distance steps of distance resolution can be finely dispersed when viewing the transmission / reception antennas 41 as a whole, thus, distance resolution can be improved.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to an RTG crane and a radar device. [Background technology]

[0002] Patent Document 1 describes an RTG crane that travels on a travel path in a container yard. The RTG crane travels on the travel path and transports containers in the container yard that are placed at any position. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-123367 Summary of the Invention [Problem to be solved by the invention]

[0004] In some cases, the RTG crane is equipped with a radar device that detects the distance to an object in order to prevent the RTG crane from coming into contact with the object when it is present in the travel path. Continuously modulated frequency radar devices have a range resolution determined by their frequency bandwidth. Therefore, to improve the range resolution of the radar device, it is necessary to change the frequency sweep width, but the frequency sweep width is limited.

[0005] An object of the present disclosure is to provide an RTG crane and a radar device that can easily improve the distance resolution of the radar device. [Means for solving the problem]

[0006] An RTG crane according to one aspect of the present disclosure is an RTG crane that travels on a travel path and is equipped with a radar device that detects the distance to an object using millimeter waves, the radar device being a continuous frequency modulation type radar device that is equipped with a plurality of transmitting antennas that transmit millimeter waves and a plurality of receiving antennas that receive reflected millimeter waves, and is provided with a delay unit that delays signals for at least one of the transmitting antennas and the receiving antennas.

[0007] This RTG crane is equipped with a continuous frequency modulation radar device that detects the distance to an object using millimeter waves. This radar device has multiple transmitting antennas that transmit millimeter waves and multiple receiving antennas that receive the reflected millimeter waves. Thus, the radar device transmits millimeter waves by sending a signal to the transmitting antenna, and detects the distance based on a signal indicating that the receiving antenna has received the reflected millimeter waves. A delay unit that delays the signal is provided for at least one of the transmitting and receiving antennas. The delay time provided by the delay unit can shift the distance step of the distance resolution in the distance direction. By setting a difference in the distance step of the distance resolution provided by the delay unit between a transmitting antenna and a receiving antenna in one pair and a transmitting antenna and a receiving antenna in another pair, the distance step of the distance resolution can be shifted from each other. As a result, the distance step of the distance resolution when viewed across the transmitting and receiving antennas can be finely distributed, thereby improving the distance resolution. As described above, the distance resolution of the radar device can be easily improved simply by providing a delay unit.

[0008] The radar device may be equipped with n transmitting antennas and m receiving antennas, and the delay times of the signals from the n transmitting antennas are different from one another, and the delay times of the signals from the m receiving antennas are different from one another, so that when the fundamental distance resolution determined from the frequency bandwidth of the continuous frequency modulation radar device is 1, the radar device may have a distance resolution of 1 / (n×m).This makes it possible to improve the distance resolution according to the number of different combinations of transmitting antennas and receiving antennas.

[0009] The delay section may delay the signal by the length of the wiring, whereby the signal is delayed by passing through a long wiring in the delay section.

[0010] The delay section may delay the signal by adding capacitance to the wiring, and the signal is delayed by being affected by the capacitance in the delay section.

[0011] A radar device according to one aspect of the present disclosure is a frequency continuous modulation type radar device that detects the distance to an object using millimeter waves, and is equipped with a plurality of transmitting antennas that transmit millimeter waves and a plurality of receiving antennas that receive reflected millimeter waves, and is provided with a delay unit that delays a signal for at least one of the transmitting antennas and the receiving antennas.

[0012] This radar device can provide the same functions and effects as the RTG crane described above. [Effects of the Invention]

[0013] According to the present disclosure, the distance resolution of a radar device can be easily improved. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a plan view showing an exemplary container terminal to which an RTG crane according to an embodiment is applied. [Figure 2] FIG. 1 is a perspective view showing an example of a group of containers to be handled and a group of adjacent containers arranged along the traveling direction of the transporting platform vehicle. [Figure 3] FIG. 1 is a perspective view showing an RTG crane according to an embodiment. [Figure 4] FIG. 2 is a schematic plan view for explaining the relationship between an RTG crane and a travel path of the RTG crane. [Figure 5] FIG. 2 is a schematic diagram showing a radar device provided in a traveling section. [Figure 6] 1 is a diagram illustrating a radar device according to an embodiment of the present invention. [Figure 7]1 is a table showing all 12 combinations and the total delay time. [Figure 8] FIG. 10 is a diagram showing the results of distance resolution processing performed using a radar device. [Figure 9] FIG. 10 illustrates an example of a delay unit. [Figure 10] FIG. 10 is a diagram showing the results of distance resolution processing performed using a radar device according to a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same or corresponding elements are designated by the same reference numerals, and redundant explanations will be omitted as appropriate. Furthermore, for ease of explanation, the drawings may be partially simplified or exaggerated, and the dimensional ratios and the like are not limited to those shown in the drawings.

[0016] Fig. 1 is a plan view showing an exemplary container terminal 1 to which the present invention is applied. As shown in Fig. 1, the container terminal 1 is provided with a container yard 2 in which containers C are placed, a plurality of gantry cranes 3 that transfer the containers C onto a berthed container ship, a plurality of RTG cranes 10 that are placed in the container yard 2 and that load and unload the containers C, and a remote control room 5 that can remotely control the plurality of RTG cranes 10.

[0017] FIG. 2 is a perspective view showing a container C and an exemplary transport vehicle 20 in a container yard 2. The transport vehicle 20 is, for example, a truck, a freight car, a trailer, or an AGV (Automated Guide Vehicle). As shown in FIGS. 1 and 2, the container yard 2 is provided with a storage area where a plurality of containers are stored, and a track (track lane) for the transport vehicle 20 to travel on. The RTG crane 10 retrieves a container C from the transport vehicle 20 that has stopped at a predetermined position, and places the container C at a predetermined address in the container yard 2. The RTG crane 10 also retrieves a container C placed in the container yard 2, transfers the container C to the transport vehicle 20, and the transport vehicle 20 carries the container C out.

[0018] As an example, the container C is an ISO standard container. The container C has a long rectangular parallelepiped shape, and for example, the longitudinal length of the container C is 20 feet or more and 45 feet or less. The height of the container C is, for example, 8.5 feet or more and 9.5 feet or less. The containers C are stacked one or more levels high in the container yard 2. The number of levels in which the containers C are arranged is sometimes called a tier.

[0019] As shown in Fig. 1, the container yard 2 has a plurality of lanes L on which containers C are placed, and a plurality of RTG cranes 10 are placed. For example, an RTG crane 10 is placed for each lane L. The number of RTG cranes 10 placed in a lane L may be one or more.

[0020] As shown in Fig. 2, containers C are stacked one or more levels in the container yard 2 to form a plurality of rows R. Each row R is aligned so that the longitudinal direction of the containers C constituting that row R (i.e., the containers C placed on that row R) is parallel to the longitudinal direction of the containers C constituting the other rows R.

[0021] If the longitudinal direction of the containers C aligned in the container yard 2 is defined as the X direction, the lateral direction of the containers C as the Y direction, and the height direction of the containers C as the Z direction, the container yard 2 extends on an XY plane, and the containers C are stacked in the Z direction at any position on the XY plane. The X direction coincides with the traveling direction of the RTG crane 10 in lane L. The Y direction coincides with the lateral movement direction of the RTG crane 10 in lane L.

[0022] Containers C form bays B, which are groups of multiple containers lined up in the Y direction and stacked in the Z direction. A plurality of bays B lined up in the X direction are provided in container yard 2. Bay B includes, for example, a group of containers to be handled B1, which is a target bay for handling containers C, and adjacent groups of containers B2 located on both sides of the group of containers to be handled B1 in the X direction.

[0023] FIG. 3 is a perspective view showing an example of an RTG crane 10 according to this embodiment, which is placed in a container yard 2. As shown in FIG. 3, the RTG crane 10 is a container handling crane that loads and unloads containers C. The RTG crane 10 is a type of crane known as a rubber-tired gantry crane (RTG crane). The RTG crane 10 automatically loads and unloads containers C placed in a container yard 2 at a container terminal 1, for example.

[0024] The RTG crane 10 includes, for example, a pair of legs 11, a crane girder 12 connecting the upper ends of the pair of legs 11, a trolley 13 that can travel laterally on the crane girder 12, a spreader 14 that loads and unloads containers C, and a pair of traveling sections 15A, 15B having wheels 23. The pair of legs 11 and the crane girder 12 are portal-shaped. The RTG crane 10 includes, for example, two sets of portal-shaped pairs of legs 11 and crane girders 12, and the two sets are arranged side by side in the X direction.

[0025] The trolley 13 moves laterally in the Y direction by, for example, driving a traverse motor. In this embodiment, the Y direction coincides with the traverse direction of the trolley 13. As an example, the trolley 13 has a winding drive unit 16 including a drum that rotates forward and reverse by a drum drive motor, and suspends the spreader 14 via a suspension member 18 including a wire. The suspension members 18 extend from the trolley 13 at two positions aligned in the X direction, and the spreader 14 is suspended from the suspension members 18 at two positions aligned in the X direction.

[0026] The spreader 14 is a hoisting device that suspends the container C. The spreader 14 has, for example, a rectangular shape extending in the X direction. The spreader 14 can hold the container C from above, and loads and unloads the container C by holding and lifting the container C. For example, the operation of the spreader 14 is controlled by the drive of the traverse motor and drum drive motor described above, and the drive of the traverse motor and drum drive motor is controlled by the crane control system 100.

[0027] The travelling sections 15A, 15B are mechanisms that travel along the linear travel path of the RTG crane 10. The RTG crane 10 includes a pair of travelling sections 15A, 15B provided below the legs 11 at both ends in the Y direction. Each of the travelling sections 15A, 15B includes a connecting member 21 that connects the legs 11 spaced apart in the X direction, and a plurality of wheel units 22 provided below the connecting member 21. One wheel unit 22 is provided at each end of the connecting member 21 in the X direction. The wheel unit 22 includes a plurality of wheels 23 and a wheel support section 24 that supports the wheels 23. The wheel support section 24 supports the wheels of a pair of wheels 23 aligned in the Y direction, and supports two pairs of the wheels 23 aligned in the X direction. Note that the number of wheels 23 included in each wheel unit 22 and the number of wheel units 22 included in each of the travelling sections 15A, 15B are not particularly limited.

[0028] The RTG crane 10 is equipped with a travel position detection unit 26 so that it can automatically travel straight along the travel path. The travel position detection unit 26 detects the travel position of the RTG crane 10 in the Y direction relative to the travel path. The travel position detection unit 26 is provided on the underside of the travel section 15A so as to detect guidelines 27 that are provided on the ground of the travel path so as to form a straight line in the X direction. For example, the guidelines 27 include magnets, and the travel position detection unit 26 is configured with a sensor that detects magnetic force. For example, when the travel section 15A is traveling straight in the X direction without any deviation in the Y direction relative to the travel path, the magnetic force detected by the travel position detection unit 26 is constant. In contrast, if the travel section 15A deviates in the Y direction relative to the travel path or its traveling direction is tilted relative to the travel path, the magnetic force detected by the travel position detection unit 26 will fluctuate. This makes it possible to detect deviations in the travel position of the RTG crane 10 based on the detection results of the travel position detection unit 26.

[0029] FIG. 4 is a schematic plan view illustrating the relationship between the RTG crane 10 and its travel paths RDA and RDB. As shown in FIG. 4, travel path 15A on one side in the Y direction travels on travel path RDA. Travel path 15B on the other side in the Y direction travels on travel path RDB. As a result, the RTG crane 10 travels in a direction parallel to the X direction, with travel path 15A traveling linearly on travel path RDA and travel path 15B traveling linearly on travel path RDB. In the following description, directions in absolute coordinates based on the travel paths RDA and RDB will be described using the X and Y directions, and the direction in which the RTG crane 10 travels will sometimes be referred to as the "travel direction D1." The horizontal direction perpendicular to the travel direction D1 will sometimes be referred to as the "lateral direction D2" of the RTG crane 10. The direction perpendicular to the travel direction D1 and the lateral direction D2 will sometimes be referred to as the "up-down direction D3."

[0030] The runway RDA extends linearly in the X direction at one end of the RTG crane 10 in the Y direction, adjacent to one side of the bay B for the container C in the Y direction. The runway RDB extends linearly in the X direction at the other end of the RTG crane 10 in the Y direction, adjacent to the other side of the bay B for the container C in the Y direction. A truck lane may be provided on the other side of the bay B for the container C in the Y direction. Each runway RDA is set slightly wider in the Y direction than the dimension of the runs 15A and 15B in the lateral direction D2. Here, as shown in FIG. 4, the direction toward one side in the running direction D1 is referred to as "direction A1," and the direction toward the other side is referred to as "direction A2." In this case, the runs 15A and 15B can travel in the direction A1. In this case, the direction A1 corresponds to the forward direction of the runs 15A and 15B in the running direction D1. Furthermore, the traveling sections 15A and 15B can travel in the direction A2, which corresponds to the forward direction of the traveling sections 15A and 15B in the traveling direction D1.

[0031] The RTG crane 10 includes a detection unit 30 attached to the RTG crane 10. The detection unit 30 detects objects present on the traveling side of the RTG crane 10 in the traveling direction. In this embodiment, the detection unit 30 is composed of detection units 30A, 30B, 30C, and 30D provided at four locations. When the traveling units 15A and 15B are traveling with the direction A1 as their traveling side, the detection units 30A and 30B detect objects present on the traveling side of the traveling units 15A and 15B in the traveling direction D1. The detection units 30A and 30B are attached to the direction A1 side of the traveling units 15A and 15B with respect to the crane girder 12. The detection units 30A and 30B detect objects present in detection target areas DEA and DEB extending on the traveling side (direction A1 side) in the traveling direction D1. The detection target areas DEA, DEB are set so that objects present on the running paths RDA, RDB within a predetermined distance on the direction A1 side as viewed from the running sections 15A, 15B, that is, the locations where the running sections 15A, 15B are expected to pass, can be detected.

[0032] When the traveling sections 15A, 15B are traveling with the direction A2 as their travel direction, the detection units 30C, 30D detect objects present on the travel direction of the traveling sections 15A, 15B in the traveling direction D1. The detection units 30C, 30D are attached to the crane girder 12 on the side of the traveling sections 15A, 15B facing the direction A2. The detection units 30C, 30D detect objects present in detection target areas DEC, DED extending on the travel direction (the direction A2 side) in the traveling direction D1. The detection target areas DEC, DED are set so that objects present on the travel paths RDA, RDB within a predetermined distance on the direction A2 side as seen from the traveling sections 15A, 15B can be detected.

[0033] As shown in FIG. 5A, in this embodiment, each detector 30 includes two radar devices 40. Note that the term "detector 30" is intended to apply to any of the detectors 30A, 30B, 30C, and 30D. A reference line SL parallel to the traveling direction D1 is set relative to the center of the traveling section 15 in the lateral direction D2. The detector 30 can detect the angle θ of the object OB relative to the reference line SL. The detector 30 measures the distances R1 and R2 of the object OB from the two radar devices 40 and can detect the angle θ of the object OB using triangulation. When determining the angle θ of the object OB using triangulation, the higher the measurement accuracy of the distances R1 and R2, i.e., the higher the distance resolution, the higher the measurement accuracy of the angle θ. Therefore, the radar device 40 according to this embodiment has a configuration that can improve distance resolution.

[0034] Next, the configuration of a radar device 40 that can improve distance resolution will be described with reference to Fig. 6. Fig. 6 is a diagram showing the radar device 40 according to this embodiment. As shown in Fig. 6, the radar device 40 is configured by providing elements and wiring on a substrate 50. Fig. 6 is a diagram showing the radar device 40 as viewed from outside the traveling section 15 in the traveling direction D1. The radar device 40 according to this embodiment uses multiple antennas on the transmitting side and the receiving side.

[0035] The radar device 40 includes a plurality of transmitting antennas 41, a plurality of receiving antennas 42, and a circuit unit 43. The plurality of transmitting antennas 41 are antennas that transmit radio waves (millimeter waves) forward. The plurality of receiving antennas 42 are antennas that receive radio waves reflected by objects. The circuit unit 43 is a device that has circuits that perform various signal processing in the radar device 40. The circuit unit 43 transmits signals to the plurality of transmitting antennas 41 and receives signals from the plurality of receiving antennas 42. Each transmitting antenna 41 is connected to the circuit unit 43 via wiring LT. Each receiving antenna 42 is connected to the circuit unit 43 via wiring LR.

[0036] The radar device 40 is a radar device 40 that employs a continuous frequency modulation method. A continuous frequency modulation radar device 40 is a type of radar that transmits radio waves, i.e., chirps, modulated so that the frequency of the transmission wave from the transmitting antenna 41 changes continuously over time. The radar device 40 generates an intermediate frequency signal (IF signal) based on the frequency difference between the transmission chirp and the reception chirp of the transmitting antenna 41. Here, the frequency of the IF signal changes in proportion to the distance to the object OB. Therefore, the radar device 40 calculates the distance to the object OB by measuring the frequency of the IF signal. Because the frequency of the transmission wave from the transmitting antenna 41 changes continuously over time, a difference occurs between the frequency of the transmitted wave and the reflected wave due to the time difference until the reflected wave returns from the object OB.

[0037] In this embodiment, the transmitting antenna 41 transmits millimeter waves as radio waves. Millimeter waves are radio waves that include a frequency band from the quasi-millimeter wave region to approximately 100 GHz. Note that quasi-millimeter waves are in a frequency band below 33 GHz and are sometimes called microwaves.

[0038] The radar device 40 includes n transmitting antennas 41 and m receiving antennas 42. In this embodiment, the number of transmitting antennas 41 is "n = 3." The number of receiving antennas 42 is "m = 4." However, the number of transmitting antennas 41 and receiving antennas 42 is not particularly limited. Microstrip antennas are used as the transmitting antennas 41 and receiving antennas 42. The patch-type transmitting antennas 41 and receiving antennas 42 have radiating electrodes 51 configured with flat plate-shaped patterns. In the example shown in FIG. 6 , the transmitting antenna 41 and receiving antenna 42 each have one radiating electrode 51, but they may each have multiple radiating electrodes 51. For example, the transmitting antenna 41 and receiving antenna 42 may have multiple (four) radiating electrodes 51 connected in series and arranged in the vertical direction D3. However, the transmitting antenna 41 and receiving antenna 42 are not limited to microstrip antennas, and other types of antennas may be used.

[0039] A delay unit 44 is provided to delay signals for at least one of the transmitting antenna 41 and the receiving antenna 42. The delay times of the signals from the n (here, n=3) transmitting antennas 41 are different from one another, and the delay times of the signals from the m (here, m=4) receiving antennas 42 are different from one another. As a result, when the theoretical distance resolution determined from the frequency bandwidth of the radar device 40 is 1, the radar device 40 has a distance resolution of 1 / (n×m).

[0040] In Japan, the sweepable frequency band in the 79 GHz band is specified in the Association of Radio Industries and Businesses (ARIB STD-T111), which is 4 GHz from 78 GHz to 81 GHz. For example, the distance resolution of an FMCW radar is expressed by the following formula (1), where c is the speed of light and B is the frequency bandwidth. When the frequency bandwidth is 4 GHz, the distance resolution is calculated using formula (1) to obtain 37.47 mm. In other words, for an FMCW radar using the 79 GHz band, the theoretical distance resolution determined by the frequency bandwidth is 37.47 mm. When the distance resolution is 37.47 mm, the time it takes for radio waves to travel this distance is 125 ps. In this way, the time it takes radio waves to travel the distance of the distance resolution is sometimes referred to as "one resolution time." In this embodiment, the theoretical distance resolution (37.47 mm) can be distributed to (n × m) points without changing the frequency bandwidth. Note that the theoretical distance resolution illustrated here is merely an example and can be changed as appropriate.

[0041]

number

[0042] In this embodiment, of the n transmitting antennas 41, no delay unit 44 is provided for one transmitting antenna 41, and a delay unit 44 is provided for each of the (n-1) transmitting antennas 41. The delay unit 44 is provided on the wiring LT of each of the (n-1) transmitting antennas 41. The delay times added by the delay unit 44 to each of the (n-1) transmitting antennas 41 are different from each other. As a result, the delay times of the signals from the n transmitting antennas 41 are different from each other. Of the m receiving antennas 42, no delay unit 44 is provided for one receiving antenna 42, and a delay unit 44 is provided for each of the (m-1) receiving antennas 42. The delay unit 44 is provided on the wiring LR of each of the (m-1) receiving antennas 42. The delay times added by the delay unit 44 to each of the (m-1) receiving antennas 42 are different from each other. As a result, the delay times of the signals from the m receiving antennas 42 are different from each other. The delay time added by the delay unit 44 is expressed as a ratio to one resolution time, and is expressed here as "X / (n×m)". X is any integer smaller than (n×m). In the following explanation, when the delay time is expressed as "X / (n×m)", it means that there is a delay of "X / (n×m)" time relative to one resolution time.

[0043] The distance resolution of the radar device 40 shown in Fig. 6 will be specifically described. For the purpose of description, the radar device 40 is assumed to have a transmitting antenna 41 identified as "Tx1," a transmitting antenna 41 identified as "Tx2," and a transmitting antenna 41 identified as "Tx3." The radar device 40 is assumed to have a receiving antenna 42 identified as "Rx1," a receiving antenna 42 identified as "Rx2," a receiving antenna 42 identified as "Rx3," and a receiving antenna 42 identified as "Rx4."

[0044] The delay time for each antenna 41, 42 will be explained. For the transmitting antenna 41 of "Tx1", X=0, and no delay unit 44 is provided. For the transmitting antenna 41 of "Tx2", X=m, and a delay time of 4 / 12 is added to the delay unit 44. For the transmitting antenna 41 of "Tx3", X=2m, and a delay time of 8 / 12 is added to the delay unit 44. For the receiving antenna 42 of "Rx1", no delay unit 44 is provided, and so there is no delay. For the receiving antenna 42 of "Rx2", a delay time of 1 / 12 is added to the delay unit 44. For the receiving antenna 42 of "Rx3", a delay time of 2 / 12 is added to the delay unit 44. For the receiving antenna 42 of "Rx4", a delay time of 3 / 12 is added to the delay unit 44.

[0045] The reflected waves of radio waves transmitted from each transmitting antenna 41 are received by each receiving antenna 42. Therefore, there are "n x m = 3 x 4 = 12" combinations of transmitting antennas 41 and receiving antennas 42. The combination of the "Txα" transmitting antenna 41 and the "Rxβ" receiving antenna 42 is referred to as the "Txα → Rxβ" combination. The delay time of the "Txα → Rxβ" combination is the sum of the delay time of the "Txα" transmitting antenna 41 and the delay time of the "Rxβ" receiving antenna 42. α is a number between 1 and 3, and β is a number between 1 and 4. For example, the delay time of the "Tx2" transmitting antenna 41 is 4 / 12, and the delay time of the "Rx3" receiving antenna 42 is 2 / 12, so the total delay time of the "Tx2 → Rx3" combination is "4 / 12 + 2 / 12 = 6 / 12." All 12 combinations of "Txα → Rxβ" and the total delay time are shown in the table in Figure 7. The delay time for each combination is shifted in increments of 1 / 12, from "0" to "11 / 12".

[0046] 8 is a diagram showing the results of distance resolution processing using the above-mentioned radar device 40. The fundamental distance resolution determined from the frequency bandwidth of the radar device 40 is set to 1. The distance resolution range for each combination of "Txα → Rxβ" is indicated by arrow E. The end of arrow E indicating the distance resolution range is the distance step for that combination.

[0047] The relationship between distance resolution and detection accuracy will be described with reference to FIG. 10 , which shows the distance resolution of a radar device 140 according to a comparative example. The radar device 140 according to the comparative example has 12 different combinations, all of which have the same distance steps: 0, 1, 2, 3, . . . The radar device 140 considers an object to exist at the point where the signal strength peaks among the distance steps 0, 1, 2, 3, . . . For example, the object OB1 shown in FIG. 10 is located exactly at distance step 2, so the signal strength peaks at distance step 2. Therefore, the radar device 140 can accurately detect the object OB1 at distance step 2. If the object OB2 is located slightly off-center from distance step 2, the signal strength peaks at distance step 2, which is closest to the object OB2 among the distance steps 0, 1, 2, 3, . . . . . . ). Therefore, the radar device 140 detects the object OB2 at distance step 2, which is offset from the actual object OB2. If the object OB3 is located at a position slightly shifted from distance step "1," the signal strength will peak at distance step "1," which is closest to the object OB3 among distance steps "0, 1, 2, 3, ...." Therefore, the radar device 140 detects the object OB3 at the position of distance step "1," which is shifted from the actual object OB3. In this way, the radar device 140 can detect the object at the distance step location in the combination of the antennas 41 and 42.

[0048] In the radar device 40 according to this embodiment shown in FIG. 8, the delay time for the combination of antennas 41 and 42 manifests as a difference in detection distance. The magnitude of the distance resolution for all 12 combinations is 1, but because the delay times for each combination are different, the arrows E indicating the distance resolution intervals are offset from one another. Because the delay times for each combination are offset by 1 / 12 from "0" to "1 1 / 12" (see FIG. 7), the arrows E indicating the distance resolution intervals are offset by 1 / 12. Therefore, the distance steps are also offset by 1 / 12. For example, the combination "Tx1 → Rx1" has no delay, so the possible distance steps are "0, 1, 2, 3...". The combination "Tx1 → Rx2" has a delay time of 1 / 12, so the possible distance steps are offset by 1 / 12, so they are "1 / 12, 1 + 1 / 12, 2 + 1 / 12, 3 + 1 / 12...". For the combination "Tx1 → Rx3", the delay time is 2 / 12, so the possible distance steps are shifted by 2 / 12, resulting in "2 / 12, 1 + 2 / 12, 2 + 2 / 12, 3 + 2 / 12...". As such, as the delay time for each combination is shifted by 1 / 12, the distance steps are also shifted by 1 / 12. For the twelfth combination "Tx3 → Rx4", the delay time is 11 / 12, so the possible distance steps are shifted by 11 / 12, resulting in "11 / 12, 1 + 11 / 12, 2 + 11 / 12, 3 + 11 / 12...". As described above, by operating 12 combinations simultaneously, the theoretical distance resolution can be reduced to 1 / 12.

[0049] For example, object OB1 shown in FIG. 8 is located exactly at distance step "2," so its signal strength peaks at distance step "2" in "Tx1 → Rx1." Therefore, the radar device 40 can accurately detect object OB1 at distance step "2" based on the signal from "Tx1 → Rx1." Object OB2, which is located slightly off-center from distance step "2," is located at "1+8 / 12." In this case, its signal strength peaks at distance step "1+8 / 12" in "Tx3 → Rx1." Therefore, the radar device 40 can accurately detect object OB2 at distance step "1+8 / 12" based on the signal from "Tx3 → Rx1." Object OB3, which is located slightly off-center from distance step "1," is located at "1+1 / 12." In this case, its signal strength peaks at distance step "1+1 / 12" in "Tx1 → Rx2." Therefore, the radar device 40 can accurately detect the object OB3 at the position of the distance step "1+1 / 12" based on the signal "Tx1→Rx2".

[0050] Next, an example of the delay unit 44 will be described with reference to FIG. 9. As shown in FIG. 9(a), the delay unit 44 may delay a signal depending on the length of the wiring LT and LR. For example, the delay unit 44 may be provided at a portion of the wiring LT and LR where the wiring length is increased by, for example, meandering the wiring LT and LR. Because a signal takes time to flow through the delay unit 44, which has a long wiring length, the signal is delayed by a time corresponding to the wiring length. Alternatively, as shown in FIG. 9(b), the delay unit 44 may delay a signal by adding a capacitance 45 to the wiring LT and LR. The signal is delayed because it takes longer to pass through the capacitance 45 than to pass through the wiring LT and LR. However, the specific configuration of the delay unit 44 is not limited to that shown in FIGS. 9(a) and 9(b), and any structure capable of delaying a signal may be used. Furthermore, the circuit unit 43 itself may have a built-in signal delay function. As shown in FIG. 6, the lengths of the wirings LT and LR relative to the antennas 41 and 42, other than the delay unit 44, are also different depending on the positions of the antennas 41 and 42. The wiring length of the delay unit 44 and the capacitance 45 are adjusted so that the delay time becomes a desired value, taking into consideration the length of the wiring LT other than the delay unit 44.

[0051] Next, the functions and effects of the RTG crane 10 and the radar device 40 according to this embodiment will be described.

[0052] The RTG crane 10 is equipped with a continuous frequency modulation radar device 40 that detects the distance to an object using millimeter waves. The radar device 40 includes multiple transmitting antennas 41 that transmit millimeter waves and multiple receiving antennas 42 that receive the reflected millimeter waves. The radar device 40 transmits millimeter waves by sending a signal to the transmitting antenna 41, and detects the distance to the object based on a signal indicating that the receiving antenna 42 has received the reflected millimeter waves. A delay unit 44 is provided to delay the signal for at least one of the transmitting antenna 41 and the receiving antenna 42. The delay time provided by the delay unit 44 can shift the distance step of the distance resolution in the distance direction. By setting a difference in the distance step of the distance resolution provided by the delay unit 44 between a transmitting antenna 41 and a receiving antenna 42 in one pair and a transmitting antenna 41 and a receiving antenna 42 in another pair, the distance steps of the distance resolution can be shifted from each other. As a result, the distance steps of the distance resolution can be finely distributed across the entire transmitting antenna 41, thereby improving the distance resolution. As described above, simply providing the delay unit 44 can easily improve the distance resolution of the radar device 40.

[0053] The radar device 40 includes n transmitting antennas 41 and m receiving antennas 42, and the delay times of the signals from the n transmitting antennas 41 are different from one another, and the delay times of the signals from the m receiving antennas 42 are different from one another. As a result, when the fundamental distance resolution determined from the frequency bandwidth of the continuous frequency modulation type radar device 40 is 1, the radar device 40 may have a distance resolution of 1 / (n×m). This makes it possible to improve the distance resolution according to the number of combinations of transmitting antennas 41 and receiving antennas 42.

[0054] The delay unit 44 may delay the signal depending on the length of the wirings LT and LR. The signal is delayed by passing through the long wirings LT and LR in the delay unit 44.

[0055] The delay unit 44 may delay the signal by adding a capacitance 45 to the lines LT and LR. The signal is affected by the capacitance 45 in the delay unit 44 and is delayed.

[0056] The radar device 40 of this embodiment is a frequency continuous modulation type radar device 40 that detects the distance to an object using millimeter waves, and is equipped with multiple transmitting antennas 41 that transmit millimeter waves and multiple receiving antennas 42 that receive reflected millimeter waves, and is provided with a delay unit 44 that delays the signal for at least one of the transmitting antennas 41 and the receiving antennas 42.

[0057] According to this radar device 40, it is possible to obtain the same functions and effects as those of the RTG crane 10 described above.

[0058] As shown in FIG. 5(b), the RTG crane 10 may need to determine whether an object OB located 14.4 m ahead of the detector 30 is within a 2.5-m-wide detection target area DE or whether it is 0.25 m away from the detection target area DE. The specifications of the RTG crane 10 define a detection / non-detection range between 0 and 0.25 m, and require detection beyond 0.25 m. In this case, the required range resolution for the radar device 40 is 6.5 mm (14.4087 m - 14.4022 m). In the radar device 140 according to the comparative example, as shown in FIG. 10, the range resolution is a fundamental range resolution based on the frequency bandwidth. In the case of an FMCW radar using the 79 GHz band, the fundamental range resolution determined by the frequency bandwidth is 37.47 mm, and the radar device 140 according to the comparative example cannot meet the 6.5 mm range resolution requirement. On the other hand, in the radar device 40 according to this embodiment, if the number of combinations of the antennas 41 and 42 is 12, the distance resolution can be set to 37.47 mm ÷ 12 = 3.12 mm. Therefore, the radar device 40 can meet the above-mentioned requirement of a distance resolution of 6.5 mm.

[0059] In the above-described embodiment, an RTG crane is used as an example, but the present invention is not limited to this. For example, a crane other than an RTG crane may be used, such as a power shovel or a forklift. [Explanation of symbols]

[0060] 10...RTG crane, 40...radar equipment, 41...transmitting antenna, 42...receiving antenna, 44...delay section, 45...capacity.

Claims

1. An RTG crane that travels on a travel path and is equipped with a radar device that detects the distance to an object using millimeter waves, The radar device is a continuous frequency modulation type radar device, a plurality of transmitting antennas for transmitting the millimeter waves; a plurality of receiving antennas for receiving the reflected millimeter waves; The RTG crane is provided with a delay unit that delays a signal for at least one of the transmitting antenna and the receiving antenna.

2. The radar device includes n transmitting antennas and m receiving antennas, The delay times of the signals from the n transmitting antennas are different from each other, The delay times of the signals from the m receiving antennas are different from each other, 2. The RTG crane according to claim 1, wherein the RTG crane has a distance resolution of 1 / (n×m) when the fundamental distance resolution determined from the frequency bandwidth of the radar device is set to 1.

3. The RTG crane according to claim 1 , wherein the delay unit delays the signal depending on the length of a wiring.

4. The RTG crane according to claim 1 , wherein the delay unit delays the signal by adding capacitance to a wiring.

5. A radar device of continuous frequency modulation type that detects the distance to an object using millimeter waves, a plurality of transmitting antennas for transmitting the millimeter waves; a plurality of receiving antennas for receiving the reflected millimeter waves; A radar device, comprising: a delay unit that delays a signal for at least one of the transmitting antenna and the receiving antenna.

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