RTG crane and object detection system for RTG crane

Abstract

An RTG crane that travels on a travel path, the RTG crane being provided with: a travel unit that travels in a travel direction; and a detection unit that detects an object present on the forward side in the traveling direction, the detection unit being provided with at least a first radar and a second radar that detect an object within a detection range by means of millimeter waves or quasi-millimeter waves, acquires the distance from the first radar and the second radar to the object, calculates a candidate point as the object to be detected on the basis of the distance, and outputs the candidate point as the object to be detected. And determines whether or not an object is present at the candidate point on the basis of the difference between the measurement parameter of the candidate point measured by the first radar and the measurement parameter of the candidate point measured by the second radar.

Description

Technical Field

[0001] The present invention relates to an RTG crane and an object detection system of the RTG crane. Background Art

[0002] Patent Document 1 describes automating part of the container transport work in a container yard. A crane transporting a container travels on a linear travel path.

[0003] Previous technical literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2004-123367 Summary of the Invention

[0006] Technical issues to be solved by the invention

[0007] In such cranes, when an object is within the travel path, it is necessary to prevent the object from coming into contact with the crane's traveling parts. Therefore, cranes are sometimes equipped with sensors that detect objects within the travel path. However, if the accuracy of such sensors is low, they may falsely detect objects outside the detection area. Therefore, there is a need to improve the accuracy of object detection.

[0008] An object of the present disclosure is to provide an RTG crane and an object detection system for the RTG crane that can improve object detection accuracy.

[0009] Means for solving technical problems

[0010] An RTG crane according to one aspect of the present disclosure travels on a travel path, and includes:

[0011] A traveling portion, which travels in the direction of travel; and

[0012] a detection unit that detects an object that is on the forward side of the traveling direction,

[0013] The detection unit includes at least a first radar and a second radar for detecting an object within a detection range using millimeter waves or quasi-millimeter waves.

[0014] The detection unit obtains the distance from the first radar and the second radar to the object, and calculates the candidate point of the object to be detected based on the distance.

[0015] The detection unit determines whether an object exists at the candidate point based on a difference between a measurement parameter of the candidate point measured by the first radar and a measurement parameter of the candidate point measured by the second radar.

[0016] This RTG crane is equipped with a detection unit that detects objects on the forward side of the crane's travel direction. Therefore, if an object that poses an obstacle is located on the forward side, the detection unit can detect it. The detection unit includes at least a first radar and a second radar that use millimeter waves or quasi-millimeter waves to detect objects within its detection range. The radars transmit radio waves, such as millimeter waves or quasi-millimeter waves, to the surrounding area and detect objects based on the intensity of the reflected waves. Furthermore, the detection unit can also detect the angle of an object by using the first and second radars. Furthermore, the detection unit obtains the distances from the first and second radars to the object and, based on these distances, calculates candidate points for objects to be detected. The detection unit then determines whether an object is present at a candidate point based on the difference between the measurement parameters of the candidate point measured by the first radar and the measurement parameters of the candidate point measured by the second radar. This prevents erroneous detection of an object at a candidate point where no object actually exists, thereby improving object detection accuracy.

[0017] The measurement parameter may be the Doppler velocity, thereby enabling high-precision calculation of whether an object exists at the candidate point.

[0018] The detection unit can convert the first Doppler velocity measured by the first radar and the second Doppler velocity measured by the second radar into velocity components in the respective radar angle directions. This makes it possible to accurately calculate whether an object exists at the candidate point.

[0019] The detection unit can determine whether the object is approaching or moving away from the detection unit. As a result, the operation of the RTG crane can be appropriately changed when the object is approaching or moving away.

[0020] The detection unit may include a first radar and a second radar provided for one traveling unit. In this case, an object existing near the one traveling unit can be detected with high accuracy.

[0021] The RTG crane can be equipped with traveling units at one end and the other end, with the first radar installed on the traveling unit at one end and the second radar installed on the traveling unit at the other end. This can reduce the number of radars in the RTG crane.

[0022] One aspect of the present disclosure relates to an object detection system for an RTG crane, comprising: a detection unit for detecting an object on the forward side of the travel direction of the RTG crane traveling on a travel path, the detection unit comprising at least a first radar and a second radar for detecting objects within a detection range using millimeter waves or quasi-millimeter waves, the detection unit obtaining the distances from the first radar and the second radar to the object, and calculating a candidate point for the object to be detected based on the distances, and determining whether the object is present at the candidate point based on a difference between a measurement parameter of the candidate point measured by the first radar and a measurement parameter of the candidate point measured by the second radar.

[0023] According to this object detection system for the RTG crane, the same operation and effects as those of the above-mentioned RTG crane can be obtained.

[0024] Effects of the Invention

[0025] According to the present disclosure, it is possible to improve the detection accuracy of an object. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a plan view showing an exemplary container terminal to which the RTG crane according to the embodiment is applied.

[0027] Figure 2 This is a perspective view showing an example of a group of containers to be loaded and unloaded and a group of adjacent containers arranged along the traveling direction of a transport vehicle.

[0028] Figure 3 It is a perspective view showing the RTG crane according to the embodiment.

[0029] Figure 4 This is a schematic plan view for explaining the relationship between an RTG crane and a travel path of the RTG crane.

[0030] Figure 5 This is a block diagram showing the configuration and functions of a crane control system of an RTG crane according to this embodiment.

[0031] Figure 6 This is a schematic perspective view of the detection unit.

[0032] Figure 7 It is a diagram showing a schematic configuration of a detection unit.

[0033] Figure 8 It is a diagram showing another example of a detection unit.

[0034] Figure 9 It is a diagram showing another example of a detection unit.

[0035] Figure 10 It is a diagram showing another example of a detection unit.

[0036] Figure 11 This is a diagram explaining the occurrence of the multipath effect.

[0037] Figure 12 This is a diagram for explaining changes in the detection range.

[0038] Figure 13 It is a diagram showing adjustment components.

[0039] Figure 14 This is a diagram illustrating adjustment components.

[0040] Figure 15 This is a diagram showing an RTG crane equipped with a first radar and a second radar.

[0041] Figure 16 It is a diagram showing the structure near the detection unit.

[0042] Figure 17 This is a flowchart showing the processing contents of the detection unit.

[0043] Figure 18 This is a flowchart showing the processing contents of the detection unit.

[0044] Figure 19 It is a graph showing the relationship between distance and angle.

[0045] Figure 20 It is a diagram used to describe candidate points and objects.

[0046] Figure 21 It is a graph showing the relationship between each candidate point and the distance and angle.

[0047] Figure 22 This is a diagram explaining Doppler velocity.

[0048] Figure 23 This is a table showing the relationship between the first speed and the second speed after conversion. DETAILED DESCRIPTION

[0049] The following describes embodiments of the present disclosure with reference to the accompanying drawings. In the accompanying drawings, identical or equivalent elements are denoted by the same reference numerals, and duplicate descriptions are omitted where appropriate. Furthermore, for ease of description, portions of the drawings may be simplified or enlarged, and dimensional ratios and other aspects are not limited to those depicted in the drawings.

[0050] Figure 1 FIG. 1 is a plan view showing an exemplary container terminal 1 to which the present invention is applied. Figure 1 As shown, the container terminal 1 is provided with: a container stacking yard 2 for arranging containers C; a plurality of gantry cranes 3 for transferring containers C to and from docked container ships; a plurality of RTG cranes 10, which are arranged at the container stacking yard 2 and carry out loading and unloading of containers C; and a remote operation room 5, which can remotely operate the plurality of RTG cranes 10.

[0051] Figure 2 2 is a perspective view showing a container C in a container yard 2 and an exemplary transport vehicle 20. The transport vehicle 20 is, for example, a truck, a van, a trailer, or an AGV (Automated Guide Vehicle). Figure 1 and Figure 2As shown, the container yard 2 is provided with a storage area for storing multiple containers and a travel path (truck lane) for a transport trolley 20. The RTG crane 10 retrieves a container C from the transport trolley 20, which is parked at a predetermined location, and places the container C at a predetermined location (address) in the container yard 2. The RTG crane 10 then retrieves the container C from the container yard 2 and transfers it to the transport trolley 20, which then transports the container C out of the container yard.

[0052] As an example, container C is an ISO-compliant container. Container C has an elongated rectangular parallelepiped shape. For example, the longitudinal length of container C is greater than 20 feet and less than 45 feet. For example, the height of container C is greater than 8.5 feet and less than 9.5 feet. Containers C are stacked in one or more layers in container yard 2. The number of layers of containers C is sometimes referred to as a tier.

[0053] like Figure 1 As shown, the container yard 2 is provided with a plurality of lanes L for arranging containers C and is equipped with a plurality of RTG cranes 10. For example, each lane L is equipped with an RTG crane 10. The number of RTG cranes 10 arranged in a lane L can be one or more.

[0054] like Figure 2 As shown, the containers C are stacked in one or more layers on the container storage yard 2 to form a plurality of rows R. The longitudinal direction of the containers C constituting each row R (i.e., the containers C loaded in the row R) is parallel to the longitudinal direction of the containers C constituting other rows R.

[0055] If the length of the containers C arranged in the container yard 2 is defined as the X direction, the width of the containers C is defined as the Y direction, and the height of the containers C is defined as the Z direction, then the container yard 2 extends on the XY plane. For example, the containers C are stacked along the Z direction at a certain position on the XY plane. The X direction coincides with the travel direction of the RTG crane 10 in the lane L. The Y direction coincides with the lateral movement direction of the RTG crane 10 in the lane L.

[0056] Containers C are arranged along the Y direction and stacked along the Z direction to form multiple container groups, or bays B. Multiple bays B are arranged side by side along the X direction in the container storage yard 2. For example, bays B include a loading and unloading bay for containers C, or loading and unloading container group B1, and adjacent container groups B2 located on either side of loading and unloading container group B1 in the X direction.

[0057] In the container yard 2, the stacking locations of the containers C are virtually set in three-dimensional space, and the virtual stacking locations of the containers C are defined as addresses (X, Y, Z). Specifically, the container yard 2 has multiple areas pre-demarcated as addresses (X, Y, Z) that can accommodate the containers C. In the addresses (X, Y, Z), "X" represents the position number, "Y" represents the column number, and "Z" represents the floor number.

[0058] Figure 3 1 is a perspective view showing an example of an RTG crane 10 according to this embodiment, which is arranged at a container yard 2. Figure 3 As shown, an 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). For example, the RTG crane 10 performs automated loading and unloading operations on containers C arranged in a container yard 2 at a container terminal 1.

[0059] For example, an RTG crane 10 includes a pair of outriggers 11, a crane girder 12 connecting the upper ends of the pair of outriggers 11, a crane tractor 13 capable of transverse movement on the crane girder 12, a spreader 14 for loading and unloading containers C, and a pair of travel sections 15A and 15B having wheels 23. The pair of outriggers 11 and the crane girder 12 form a portal shape. For example, the RTG crane 10 includes two sets of a pair of outriggers 11 and the crane girder 12 in a portal shape, and these two sets are arranged side by side in the X direction.

[0060] For example, the crane trolley 13 is driven by a traverse motor to traverse in the Y direction. In this embodiment, the Y direction coincides with the traverse direction of the crane trolley 13. For example, the crane trolley 13 includes a winding drive unit 16 comprising a drum that is rotated forward and reversely by a drum drive motor. The hoist 14 is suspended via a suspension member 18 comprising a wire rope. The suspension members 18 extend from two locations aligned in the X direction on the crane trolley 13, and the hoist 14 is suspended by the suspension members 18 at the two locations aligned in the X direction.

[0061] The spreader 14 is a lifting device for suspending the container C. For example, the spreader 14 has a rectangular shape extending in the X-direction. The spreader 14 can lock onto the container C from above and load and unload the container C by locking and lifting it. For example, the movement of the spreader 14 is controlled by the drive of the aforementioned traverse motor and drum drive motor, which are controlled by the crane control system 100.

[0062] The traveling sections 15A and 15B are mechanisms that travel along the linear travel path of the RTG crane 10. The RTG crane 10 includes a pair of traveling sections 15A and 15B, located below each outrigger 11 at both ends in the Y direction. Each traveling section 15A and 15B includes a connecting member 21 that connects the outriggers 11 that are spaced apart in the X direction, and a plurality of wheel units 22 located below the connecting member 21. One wheel unit 22 is located at each end of the connecting member 21 in the X direction. The wheel units 22 include a plurality of wheels 23 and a wheel support 24 that supports the wheels 23. The wheel support 24 supports a pair of wheels 23 aligned in the Y direction, supporting the pair of wheels 23 as two sets aligned in the X direction. The number of wheels 23 in a wheel unit 22 and the number of wheel units 22 in each traveling section 15A or 15B are not particularly limited.

[0063] The RTG crane 10 is equipped with a travel position detection unit 26 to enable it to automatically travel straight along its 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 located on the underside of the travel unit 15A and detects a guide wire 27 arranged linearly along the X direction on the ground surface of the travel path. For example, the guide wire 27 may include a magnet, and the travel position detection unit 26 may be comprised of a sensor that detects magnetic force. For example, when the travel unit 15A travels straight along the X direction without deviating from the travel path in the Y direction, the magnetic force detected by the travel position detection unit 26 is constant. In contrast, if the travel unit 15A deviates from the travel path in the Y direction or the travel direction tilts relative to the travel path, the magnetic force detected by the travel position detection unit 26 will fluctuate. This allows the detection results of the travel position detection unit 26 to detect deviations in the travel position of the RTG crane 10.

[0064] Figure 4 1 is a schematic plan view for explaining the relationship between the RTG crane 10 and the travel paths RDA and RDB of the RTG crane 10. Figure 4As shown, the traveling unit 15A located on one side in the Y direction travels along a travel path RDA. The traveling unit 15B located on the other side in the Y direction travels along a travel path RDB. Thus, with the traveling unit 15A traveling linearly along the travel path RDA and the traveling unit 15B traveling linearly along the travel path RDB, the RTG crane 10 travels in a direction parallel to the X direction. In the following description, the X and Y directions, which are absolute coordinates based on the travel paths RDA and RDB, will be used. The direction in which the RTG crane 10 travels will sometimes be referred to as the "travel direction D1." Furthermore, the horizontal direction perpendicular to the travel direction D1 will sometimes be referred to as the "width direction D2" of the RTG crane 10.

[0065] The travel path RDA extends linearly in the X direction at a position adjacent to one side of the bay B of the container C in the Y direction on one end side of the RTG crane 10 in the Y direction. The RDB extends linearly in the X direction at a position adjacent to the other side of the bay B of the container C in the Y direction on the other end side of the RTG crane 10 in the Y direction. Each of the travel paths RDA and RDB is set to be slightly wider in the Y direction than the dimension of the width direction D2 of the travel parts 15A and 15B. Figure 4 As shown, let the direction on one side of the driving direction D1 be "direction A1" and the direction on the other side be "direction A2." In this case, the driving units 15A and 15B can travel in direction A1. In this case, direction A1 corresponds to the forward direction of the driving units 15A and 15B in the driving direction D1. Furthermore, the driving units 15A and 15B can travel in direction A2. In this case, direction A2 corresponds to the forward direction of the driving units 15A and 15B in the driving direction D1.

[0066] The RTG crane 10 includes a detection unit 30 mounted thereon. The detection unit 30 detects objects on the forward side of the RTG crane 10 in its travel direction. In this embodiment, the detection unit 30 is comprised of detection units 30A, 30B, 30C, and 30D installed at four locations. When the traveling units 15A and 15B travel in the direction A1, the detection units 30A and 30B detect objects on the forward side of the traveling units 15A and 15B in the travel direction D1. The detection units 30A and 30B are mounted on the A1-facing side of the traveling units 15A and 15B relative to the crane main girder 12. The detection units 30A and 30B detect objects within detection target areas DEA and DEB extending along the forward side (the A1-facing side) in the travel direction D1. The detection target areas DEA and DEB are set to be able to detect objects present where the traveling units 15A and 15B are scheduled to pass (ie, on the traveling routes RDA and RDB within a predetermined distance toward A1 when viewed from the traveling units 15A and 15B).

[0067] When the traveling units 15A and 15B are traveling toward A2, the detection units 30C and 30D detect objects on the traveling side of the traveling units 15A and 15B in the traveling direction D1. The detection units 30C and 30D are mounted on the traveling units 15A and 15B on the A2 side relative to the crane main girder 12. The detection units 30C and 30D detect objects within the detection target areas DEC and DED, which extend along the traveling side (toward A2) in the traveling direction D1. The detection target areas DEC and DED are designed to detect objects within the area where the traveling units 15A and 15B are scheduled to pass (i.e., within a predetermined distance range toward A2 when viewed from the traveling units 15A and 15B).

[0068] Next, refer to Figure 5 Next, a functional block configuration of a crane control system 100 including an object detection system 120 for an RTG crane according to this embodiment will be described. Figure 5 1 is a block diagram showing the structure and functions of a crane control system 100 including an object detection system 120 for an RTG crane according to this embodiment. Figure 5 As shown, the crane control system 100 includes a control device 110. The control device 110 receives detection results from the detection unit 30. Furthermore, the control device 110 receives detection results from the travel position detection unit 26. The control device 110 outputs control signals to the drive unit 55 and output unit 51 of the RTG crane 10. The location of the control device 110 is not particularly limited and can be located anywhere on the RTG crane 10 or at a location remote from the RTG crane 10.

[0069] The drive unit 55 generates the driving force for moving the spreader 14 along the designated transport path, and also generates the driving force for moving the travel units 15A and 15B according to the designated motion. Examples of the drive unit 55 include the hoisting device for the spreader 14, the traverse motor for the crane trolley 13, and the travel motors for the travel units 15A and 15B. The output unit 51 outputs various types of information. Examples include a display, a speaker, and a warning light.

[0070] For example, the control device 110 has a processor, a memory, a storage device and a communication interface, and can be configured as a computer (also called an onboard automatic control PC). The processor is a computing unit such as a CPU (Central Processing Unit). The memory is a storage component such as a ROM (Read Only Memory) or a RAM (Random Access Memory). The storage device is a storage component (storage medium) such as an HDD (Hard Disk Drive). The communication interface is a communication device that realizes data communication. The processor controls the memory, the storage device and the communication interface to realize the functions of the control device 110 described later. In the control device 110, for example, the program stored in the ROM is loaded into the RAM, and various functions are realized by executing the program loaded into the RAM by the CPU. The number of computers constituting the control device 110 can be one or more.

[0071] The control device 110 includes an information processing unit 111 (detection unit), a path setting unit 112 , a drive control unit 113 , and a warning control unit 114 .

[0072] The information processing unit 111 acquires information related to the detection results from the detection unit 30 and, based on these results, detects objects within the detection range. Thus, the information processing unit 111 also functions as the detection unit 30, detecting objects on the forward side of the RTG crane 10 in its travel direction D1. Furthermore, the information processing unit 111 determines whether an obstacle exists within the detection range DS. The path setting unit 112 sets the transport path for the container C to be transferred by the spreader 14 of the RTG crane 10.

[0073] The drive control unit 113 controls the drive unit 55 to move the spreader 14 along the transport path set by the path setting unit 112. Furthermore, the drive control unit 113 controls the travel of the traveling units 15A and 15B based on the detection results of the detection unit 30. The drive control unit 113 sends control signals to various devices, such as the motor, that comprise the drive unit 55. Consequently, the drive control unit 113 controls the spreader 14 to move along the predefined transport path and controls the traveling units 15A and 15B to perform the desired operations. For example, if the drive control unit 113 detects the presence of an object within the detection range DS of the detection unit 30, it stops the traveling units 15A and 15B.

[0074] If a safety measure is required, the warning control unit 114 controls the output unit 51 to issue a warning to the user. For example, the warning control unit 114 issues a warning when an object is detected within the detection range of the detection unit 30 .

[0075] [Testing Department]

[0076] Next, refer to Figure 6 and Figure 7 The structure of the detection unit 30 will be described in detail. The RTG crane in the comparative example uses a radar sensor that detects objects using radio waves such as millimeter waves or quasi-millimeter waves. Radio waves are reflected by containers located near the travel path, sometimes causing objects outside the detection area to be mistakenly detected as virtual images. The detection unit 30 in this embodiment can prevent such false detections. While the description here focuses on detection unit 30C among the four detection units 30A, 30B, 30C, and 30D, the other detection units 30A, 30B, and 30D also have similar structures. Figure 6 Detection unit 30C is a schematic perspective view showing a schematic configuration of a detection unit 30C. Detection unit 30C includes a radar 31 and an adjustment unit 32 .

[0077] The radar 31 detects objects within the detection range DS using millimeter waves or quasi-millimeter waves. In this embodiment, the millimeter waves or quasi-millimeter waves emitted by the radar 31 are referred to as radio waves MW. In this embodiment, the detection unit 30C includes one radar 31 and one adjustment unit 32. Therefore, one radar 31 and one adjustment unit 32 of the detection unit 30C are provided on the traveling unit 15A at one end in the width direction D2 facing the A2 side, and one radar 31 and one adjustment unit 32 of the detection unit 30D are provided on the traveling unit 15B at the other end. One radar 31 and one adjustment unit 32 of the detection unit 30A are provided on the traveling unit 15A at one end in the width direction D2 facing the A1 side, and one radar 31 and one adjustment unit 32 of the detection unit 30B are provided on the traveling unit 15B at the other end.

[0078] Quasi-millimeter waves, sometimes also called microwaves, have a frequency bandwidth less than 33 GHz. Millimeter waves cover a frequency band from around 100 GHz to above 33 GHz. The radio waves MW emitted by the radar 31 are defined as radio waves in a frequency band from the quasi-millimeter wave region to approximately 100 GHz.

[0079] The radar 31 includes a radar main unit 33, a transmitting antenna 34, and a receiving antenna 36. The radar main unit 33 is mounted on the RTG crane 10. The transmitting antenna 34 transmits radio waves MW forward. The receiving antenna 36 receives the reflected radio waves MW. The radar 31 detects objects by receiving the reflected radio waves MW via the receiving antenna 36. Since the radar 31 includes a single transmitting antenna 34 and a single receiving antenna 36, ​​angular resolution processing is not possible.

[0080] The adjustment unit 32 adjusts the attenuation rate of the millimeter wave or quasi-millimeter wave. The adjustment unit 32 has an adjustment component 37 disposed on the forward side (toward the A2 side) of the travel direction D1 of the radar 31. In addition, the attenuation rate is a value obtained based on the intensity ratio of the radio wave MW before and after passing through the adjustment component 37. Figure 6 In the example shown, the adjustment member 37 is in the shape of a semicircle when viewed from above and extends in the vertical direction with a constant cross-sectional shape. In this embodiment, the adjustment member 37 is in the shape of a semicircle of 180 degrees.

[0081] like Figure 7 As shown in (a), the detection range DS is set according to the detection target area. For example, the detection range DS can be set to a range where the intensity of the transmitted millimeter waves or quasi-millimeter waves is attenuated by half. The intensity of the radio waves reflected from objects outside the detection range DS is set to be sufficiently low. The adjustment unit 32 is arranged to be line-symmetrical with respect to the reference line CL of the radar 31 when viewed from above. Furthermore, the adjustment unit 32 is curved to convexly face toward A2.

[0082] like Figure 7 As shown in (b), the adjustment unit 32 adjusts the attenuation rate so that the attenuation rate increases in the portion with a larger angle relative to the reference line CL. Thus, the adjustment unit 32 can limit the width of the detection range DS to within the width of the detection target area DEC. Furthermore, the adjustment unit 32 gradually increases the attenuation rate from the portion on the side of the reference line CL toward the portion with a larger angle. The dielectric loss of the portion with a larger angle relative to the reference line CL is greater than that of the portion on the side of the reference line CL. The thickness of the adjustment unit 32 can be set to be constant.

[0083] Specifically, if Figure 7As shown in (a), the adjustment portion 32 has dielectric loss adjustment portions 41a, 41b, 41c, 41d, 41e, 41f, and 41g in sequence from the reference line CL toward the direction in which the angle increases. In addition, the dielectric loss adjustment portions 41b, 41c, 41d, 41e, 41f, and 41g are arranged in pairs in a line-symmetrical manner relative to the reference line CL, but the symbol is only marked on one of them. The dielectric loss adjustment portions 41a, 41b, 41c, 41d, 41e, 41f, and 41g are arranged at approximately equal intervals. The dielectric loss adjustment portion 41a is arranged on the reference line CL, and the dielectric loss adjustment portion 41g is arranged at the end of the arc of the adjustment portion 32. The dielectric loss of the dielectric loss adjustment portion 41a is the lowest, and the dielectric loss of the dielectric loss adjustment portion 41g is the highest. The dielectric loss increases in stages in the order of dielectric loss adjustment sections 41a, 41b, 41c, 41d, 41e, 41f, and 41g. Furthermore, dielectric loss adjustment sections 41a, 41b, 41c, 41d, 41e, 41f, and 41g adjust the dielectric loss by using materials having the desired dielectric loss at various locations within adjustment member 37. Materials used to form the dielectric loss adjustment section of adjustment member 37 include water, ethanol, and epoxy resin. Furthermore, the material used to adjust adjustment section 32 adjusts the relative permittivity and dielectric loss factor, and as a result, the dielectric loss (electrical power of radio waves) is adjusted.

[0084] like Figure 7 As shown in (b), the dielectric loss adjustment sections 41a, 41b, 41c, 41d, 41e, 41f, and 41g provide the radio wave's reach ranges DSa, DSb, DSc, DSd, DSe, DSf, and DSg. The reach range DSa of the dielectric loss adjustment section 41a on the baseline CL has a smaller expansion in the width direction D2, thus minimizing the attenuation rate. Therefore, the intensity of the radio wave after passing through the dielectric loss adjustment section 41a becomes the strongest. The reach range DSg of the dielectric loss adjustment section 41g, which has the largest angle, has a larger expansion in the width direction D2 and immediately reaches the edge of the detection target area DEC, thus maximizing the attenuation rate. Therefore, the intensity of the radio wave after passing through the dielectric loss adjustment section 41g becomes the weakest. The attenuation rate increases in the order of the reach ranges DSa, DSb, DSc, DSd, DSe, DSf, and DSg, and the intensity of the radio wave gradually decreases in this order. Thus, the adjustment unit 32 can gradually increase the attenuation rate from the portion with a large angle toward the reference line CL. Furthermore, the adjustment unit 32 can increase the attenuation rate of the portion with a large angle relative to the reference line CL. Figure 7In the example, the dielectric loss is changed in stages, but it can also be changed continuously without setting a limit. Furthermore, to suppress the multipath effect, the range of the radio wave's reach does not necessarily need to be limited to the width of the detection target area DEC; it can also be limited to a range that prevents secondary reflection from the container. Secondary reflection from the container means, for example, reflecting on the left (right) container and then reflecting on the right (left) container.

[0085] The shape of the adjustment member 37 is not particularly limited. Figure 8 As shown in (a), when viewed from above, a flat plate-shaped adjustment member 37 can be used. Figure 8 As shown in (b), a spherical adjustment member 37 may also be used. A dielectric loss adjustment portion 41a having a circular shape when viewed from the front is provided at the center of the spherical adjustment member 37. Ring-shaped dielectric loss adjustment portions 41b, 41c, 41d, 41e, 41f, and 41g having an annular shape when viewed from the front are provided in order from the center toward the periphery.

[0086] In the adjustment section 32, in order to control the attenuation rate of radio waves, materials with different dielectric loss are used in the material of the adjustment member 37. Alternatively, the same material can be used throughout the adjustment member 37, and the attenuation rate of radio waves can be controlled by changing its thickness. For example, Figure 9 As shown in (a), a cavity-type meniscus lens container can be prepared, the portion on the reference line CL is adjusted to be the thinnest, and the portion with a larger angle is adjusted to be thicker. A liquid with a large dielectric loss, such as methanol or water, is filled in the container to form a meniscus lens portion 43. Alternatively, the meniscus lens portion 43 can be formed from a material with a large dielectric loss, such as epoxy resin. Alternatively, the meniscus lens portion 43 can be arranged on the lens surface to form an adjustment member 37. And, for example, as Figure 9 As shown in (b), the adjustment member 37 can also be formed by placing a concave lens 44 adjusted so that the portion on the reference line CL is thinnest and the portion with a larger angle is thicker on the back of the lens. The concave lens 44 can be a biconcave lens or a plano-concave lens. In addition, a spherical lens 45 for correcting the emission characteristics of the radio wave can also be placed at the same time.

[0087] The following describes a specific example of designing the surface thickness of the meniscus lens portion 43. This example uses a radio wave with a frequency of 50 GHz. The dielectric loss factor tanδ of methanol is set to 0.245. If the dielectric loss ε is set to 6, then "√ε·tanδ = 0.6." Furthermore, the power halving depth D is expressed by equation (1).

[0088] [Formula 1]

[0089]

[0090] Therefore, it becomes "D = 3.32 × 10 7 / (50×10 9 × 0.6) = 0.11 × 10 -2 =1.1 mm". Therefore, the thickness of the liquid portion can be set to "0 mm" on the front surface of the meniscus lens portion 43 where the distance becomes the largest, and the thickness of the liquid portion can be set to "1.1 mm" at an angle corresponding to half the distance.

[0091] You can also use Figure 10 The adjustment component 37 shown. The adjustment component 37 includes a wall portion 70 on the incident side and a wall portion 71 on the emission side, which are separated from each other along the X-axis direction. A protrusion 72 is formed at the center of the wall portion 71, which protrudes in a mountain shape toward the wall portion 70. The wall portion 70, the wall portion 71, and the protrusion 72 are formed of a member with a low attenuation rate, such as ABS. An attenuation material 73, such as water, ethanol, or epoxy resin, is contained in the space between the wall portion 70 and the wall portion 71. The top of the protrusion 72 is arranged on the reference line CL, so the thickness of the ABS is large. As the angle increases, the thickness of the ABS decreases, and the thickness of the attenuation material 73 increases. Therefore, the attenuation rate of the portion with a large angle increases. In addition, the wall portion 70 can be set as the emission side and the wall portion 71 can be set as the incident side.

[0092] The functions and effects of the RTG crane according to this embodiment will be described.

[0093] First, refer to Figure 11The RTG crane 150 according to the comparative example will be described. The detection unit 30C of the RTG crane 150 according to the comparative example does not include the aforementioned adjustment unit 32. Therefore, the attenuation rate of the radio wave MW of the radar 31 is not adjusted. Among the radio waves MW transmitted from the radar 31, the radio wave MWa directed toward the left container Ca is reflected by that container Ca and travels toward the right container Cb. This results in the detection of an object 50B near the container Cb. Although objects 50A and 50B are at the same distance from the radio wave MW, object 50A is within the detection area DEC, while object 50B is outside. The RTG crane 150 according to the comparative example cannot distinguish whether an object is inside or outside the detection area DEC. Consequently, the radar 31 detects a virtual image, namely, object 50B, located opposite the left container Ca, resulting in a multipath effect. This can make it difficult for the RTG crane 150 to perform normal measurements. Furthermore, since containers are generally made of metal, the intensity of the radio waves MW reflected from the containers is greater than the intensity of the radio waves MW reflected from a human body, etc. Therefore, it is impossible to distinguish between reflections from containers outside the detection target area DEC and reflections from a human being within the detection target area DEC, and the detection sensitivity of objects within the detection target area DEC may be reduced.

[0094] In contrast, the RTG crane 10 according to this embodiment includes a detection unit 30 for detecting objects on the forward side of the travel direction D1. Therefore, if an object that acts as an obstacle is present on the forward side, the detection unit 30 can detect it. The detection unit 30 includes at least one radar that uses millimeter waves or quasi-millimeter waves to detect objects within a detection range DS. The radar transmits radio waves such as millimeter waves or quasi-millimeter waves to the surrounding area and detects objects based on the intensity of the reflected waves. The detection unit 30 also includes an adjustment unit 32 for adjusting the attenuation rate of the millimeter waves or quasi-millimeter waves. The adjustment unit 32 adjusts the attenuation rate to reduce the strong reflected waves caused by objects outside the detection range DS, thereby improving the detection sensitivity of objects within the detection range DS relative to objects outside the detection target area.

[0095] The detection range DS extends at a predetermined angle relative to the radar's reference line CL when viewed from above. The adjustment unit 32 adjusts the attenuation rate to increase the attenuation rate in the portion with a larger angle relative to the reference line CL. Within the detection range DS, the portion with a larger angle relative to the reference line CL is where the radio waves MW, expanding along the width direction D2, are reflected by containers and other objects, causing multipath effects. Therefore, by increasing the attenuation rate in the portion with a larger angle relative to the reference line CL by the adjustment unit 32, it is possible to suppress the occurrence of multipath effects on the radio waves MW and other factors that reduce detection sensitivity.

[0096] The adjustment portion 32 may increase the attenuation rate stepwise from the portion on the reference line CL side toward the portion with a larger angle. In this case, the adjustment portion 32 can be manufactured more easily than an adjustment portion 32 in which the attenuation rate is continuously increased.

[0097] The adjustment unit 32 may include an adjustment member 37 disposed on the forward side of the traveling direction D1 relative to the radar 31. In this case, the adjustment unit 32 can be easily configured simply by disposing the adjustment member 37 relative to the radar 31.

[0098] The portion of the adjustment section 32 with a larger angle can have a higher dielectric loss than the portion on the reference line CL side. In this case, the adjustment section 32 can allow radio waves to pass through with high intensity due to low dielectric loss on the reference line CL side, thereby reducing the attenuation rate. On the other hand, the adjustment section 32 can allow radio waves to pass through with low intensity due to high dielectric loss on the portion with a larger angle, thereby increasing the attenuation rate.

[0099] [Changes in detection range]

[0100] like Figure 12 As shown, in the RTG crane 10, the limited detection range DS can be changed by the adjustment unit 32 according to the change of the travel direction. Figure 12 As shown in (a), if the detection range of the radar 31 when not restricted is set to "DSB" indicated by the dotted line, the restricted detection range DS becomes narrower than the detection range DSB. When the RTG crane is traveling straight and the X-axis direction is parallel to the travel direction D1, the detection range DS of the detection unit 30 is set so that the reference line CL of the radar 31 coincides with the center line CL1 of the detection range DS.

[0101] In contrast, Figure 12 As shown in (b), when the RTG crane 10 slews and changes its travel direction from D1 to D3, the detection range DS is shifted toward the forward side of the travel direction D3. At this time, the center line CL1 of the detection range DS is tilted relative to the reference line CL of the radar 31.

[0102] refer to Figure 13 and Figure 14 , the mechanism for causing the detection unit 30C to change the detection range DS will be described. Figure 13 As shown in (a), the adjustment component 37 has a Figure 7 The adjustment member 37 has a larger angle of 180 degrees. The adjustment member 37 has dielectric loss adjustment parts 41a, 41b, 41c, 41d, 41e, 41f, 41g, and 41h arranged to surround the radar 31. The adjustment member 37 is configured to be rotatable around the radar 31. Figure 13As shown in (b) and (c), the adjustment member 37 has a cylindrical shape and can have the function of limiting the emission angle in the vertical direction.

[0103] like Figure 14 As shown in (a), when the RTG crane 10 is turned left, the adjustment member 37 is rotated to the left, so that the radio wave MW with the largest intensity is emitted. MAX The direction moves in the left direction. And, as Figure 14 As shown in (b), when the RTG crane 10 is turned right, the adjustment member 37 is rotated to the right, so that the radio wave MW with the maximum intensity is emitted. MAX In this way, the traveling direction of the RTG crane 10 and the radio wave MW MAX The directions of the two axes are the same.

[0104] like Figure 14 As shown in (c), a material 56 with a large dielectric loss is disposed inside or outside the cylindrical lens 54. The thickness of the adjustment member 37 is thin at the center and becomes continuously thicker as the angle relative to the center increases.

[0105] The RTG crane 10 is provided with a detection unit 30 for detecting an object existing on the forward side of the travel direction. Therefore, when an object 50 that becomes an obstacle exists on the forward side, the detection unit 30 can detect the object. Here, the detection unit 30 is provided with at least one radar 31 for detecting an object within the detection range DS by using millimeter waves or quasi-millimeter waves. Therefore, the radar 31 detects an object based on the intensity of the reflected wave reflected on the object by transmitting radio waves such as millimeter waves or quasi-millimeter waves to the surroundings. In addition, the detection unit 30 is provided with an adjustment unit 32 for adjusting the attenuation rate of the millimeter waves or quasi-millimeter waves. Therefore, the adjustment unit 32 can suppress the detection of unnecessary objects by adjusting the attenuation rate to reduce the intensity of the reflected wave from the portion of the detection range DS where the possibility of contact with the object is low. Moreover, the detection range DS is changed by the adjustment unit 32 according to the change of the travel direction. Therefore, if the travel direction is taken into consideration, the portion where the possibility of contact with the object is low can be excluded from the detection range DS. For example, as Figure 12 As shown in (b), when the RTG crane 10 swings to the left, the likelihood of contact with object 50 on the right side is low. Therefore, if object 50 were detected within the pre-limited detection range DSB, unnecessary stops or deceleration would result. In contrast, by limiting the detection range DS and changing it in the direction of the swing, object 50 can be excluded from the detection range DS. This allows the detection range DS to be appropriately set at the location where object detection is required, thereby improving the detection sensitivity of objects within the detection range.

[0106] While the above embodiment illustrates an RTG crane as an example of an industrial vehicle, the type of industrial vehicle is not particularly limited. For example, an industrial vehicle may be a crane other than an RTG crane, an excavator, or a forklift. Furthermore, in the case of a forklift, the direction of travel during reverse can be considered the direction of travel. Industrial vehicles do not include ordinary vehicles such as cars that travel on public roads.

[0107] [Collaboration of radar]

[0108] For example, Figure 15 As shown, an industrial vehicle M, such as a truck, sometimes passes in the forward direction of the RTG crane 10, crossing the detection target areas DEC and DED. In this case, if the industrial vehicle M moves relatively away from the RTG crane 10, the RTG crane 10 continues traveling; otherwise, the RTG crane 10 slows down or stops. Furthermore, in order to identify that the industrial vehicle M is within the detection target areas DEC and DED, it is necessary to measure the distance and angle to the industrial vehicle M. The detection unit 30C used here includes a first radar 31A and a second radar 31B. Furthermore, an adjustment unit 32 can be provided for each of the first radar 31A and the second radar 31B to mitigate the effects of multipath even when a container is positioned close to the travel path. Therefore, the detection unit 30C performs angle calculations instead of the usual angle resolution process. Furthermore, by providing an adjustment component to change the propagation direction of the millimeter wave or quasi-millimeter wave, the detection unit 30C can correct the propagation direction as needed during angle calculation.

[0109] Here, as a method for performing angle resolution using a millimeter wave sensor, there is a method of configuring multiple receiving antennas in the angular direction to be resolved and calculating the phase difference between the antennas. In this method, the angular resolution is expressed as "θres = 2 / N*180 / π". When the number of antennas built into a typical MMIC is 12, an angular resolution of approximately 9.6 degrees can be calculated. In contrast, Figure 16 As shown, to accurately determine whether an object detected by a millimeter wave sensor is within or outside the detection range, a resolution significantly higher than 9.6 degrees is required. To improve resolution, significantly increasing the number of antennas would increase the substrate area and signal processing, leading to increased manufacturing costs. This embodiment can address these issues.

[0110] Specifically, in this embodiment, if Figure 16As shown, the first radar 31A and the second radar 31B are arranged to be separated by a distance r3 (for example, 2m) in the width direction D2. The detection range DS1 of the first radar 31A and the detection range DS2 of the second radar 31B are offset from each other in the width direction D2. The detection ranges DS1 and DS2 overlap with each other in a manner including the detection object area DEC. When there is an object 50, the distance detection result LR1 based on the first radar 31A is represented by a double-dotted line, and the distance detection result LR2 based on the second radar 31B is represented by a dotted line. Assuming that the distance between the first radar 31A and the object 50 is r1, the distance detection result LR1 becomes an arc with a radius of the distance r1. Assuming that the distance between the second radar 31B and the object 50 is r2, the distance detection result LR2 becomes an arc with a radius of the distance r2. Detection unit 30 ( Figure 5 The information processing unit (hereinafter referred to as the "information processing unit") can calculate the angle θ of the object 50 based on the three distances r1, r2, and r3. The angle θ is defined as the angle between the line segment connecting the first radar 31A and the object 50 and the line segment connecting the second radar 31B and the object 50.

[0111] Next, refer to Figures 17 to 21 , the processing content of the detection unit 30 is explained. Figure 17 and Figure 18 1 is a flowchart showing the processing contents calculated by the information processing unit 111 of the detection unit 30. The detection unit 30 obtains the distances from the first radar 31A and the second radar 31B to the object, and calculates candidate points of the object to be detected based on the distances. Figure 17 The processing starts when the candidate point is calculated by the detection unit 30. Figure 17 As shown, the detection unit 30 uses the first radar 31A and the second radar 31B to measure the distance to the candidate point (step S10). The detection unit 30 determines whether there are multiple detected candidate points (step S20). If the number of candidate points captured by each radar 31A and 31B is one and the actual object position is one, the result of the distance decomposition processing is that the number of candidate points for radars 31A and 31B is one. Therefore, if the number of candidate points detected by radars 31A and 31B is one, the determination in step S20 is "yes", and the detection unit 30 determines that an object is present at the candidate point.

[0112] If the answer is "yes" in step S20, the detection unit 30 calculates the angle θ of the object (step S30). Figure 19 As shown in (a), if the angle between the line segment representing the distance r1 and the line segment representing the distance r2 is θ, then “cosθ=(r1 2 +r2 2 -r3 2 ) / (2r1·r2)”, the angle θ can be calculated by the following formula (2).

[0113] [Formula 2]

[0114]

[0115] Next, the detection unit 30 determines whether the detected object is outside the range of the detection target area DEC (step S40). If the answer in step S40 is "yes", go to step S41. Figure 18 If the answer to step S40 is "No", the RTG crane 10 performs actions such as deceleration or stopping (step S50). After step S50, go to Figure 18 processing.

[0116] The case where the determination result in step S20 is "No" is described below. The detection unit 30 determines whether an object exists at the candidate point based on the difference between the measurement parameter of the candidate point measured by the first radar 31A and the measurement parameter of the candidate point measured by the second radar 31B. In this embodiment, the Doppler velocity is used as the measurement parameter. For a method of finding a candidate point where an object exists, refer to Figures 20 to 23 For explanation. Figure 20 As shown, assume that the first radar 31A measures distances and detects two distances: r1a (e.g., 5.93m) and r1b (e.g., 4.70m). Furthermore, assume that the second radar 31B measures distances and detects two distances: r2a (e.g., 5.15m) and r2b (e.g., 4.10m). In this case, a maximum of four intersection points (number of detections by the first radar 31A x number of detections by the second radar 31B) are generated as candidate points. However, since the number of objects is the same as the number detected by the radars, the detection unit 30 must determine whether an object exists at the candidate point and select two candidate points as candidate points where an object exists.

[0117] exist Figure 20 In the image, there are actually two objects 50A and 50B, but three candidate points 60A, 60B, and 60C are detected. In addition, although not shown, a candidate point 60D is detected as the intersection of the distance r1a and the distance r2b (see Figure 21 (d)). Figure 21 The figure shows a triangle for calculating the angle θ at each candidate point 60A, 60B, 60C, and 60D. The angle θ at each candidate point 60A, 60B, 60C, and 60D is calculated using equation (2). The angle θ at candidate point 60A is 19.05°, the angle θ at candidate point 60B is 25.1°, the angle θ at candidate point 60C is 22.85°, and the angle θ at candidate point 60D is 9.39°.

[0118] Next, the detection unit 30 detects the Doppler velocity corresponding to the distance measured by each radar 31A, 31B. Figure 22 Velocity will be described. First, the detection unit 30 measures the Doppler velocity of the candidate point 60 using the first radar 31A, namely, the first velocity V1, which is the velocity component in the direction from the candidate point 60 toward the first radar 31A. Next, the detection unit 30 measures the Doppler velocity of the candidate point 60 using the second radar 31B, namely, the second velocity V2, which is the velocity component in the direction from the candidate point 60 toward the second radar 31B.

[0119] If the moving direction of the candidate point 60 is closer to the second velocity V2 than the first velocity V1, then the first velocity V1 is slower than the second velocity V2, which can be expressed by the following equation (3). If the moving direction of the candidate point 60 is closer to the first velocity v1 than the second velocity V2, then the first velocity V1 is faster than the second velocity V2, which can be expressed by the following equation (4).

[0120] V1=V2·cosθ…(3)

[0121] V1=V2 / cosθ…(4)

[0122] The second velocity V2 measured by the second radar 31b is converted to a velocity in the first velocity direction using equations (3) and (4). If either of the two converted velocities is close to the value of the first velocity V1 measured by the first radar 31A, it can be determined that an object is present at the candidate point.

[0123] Return to Figure 21 As a specific example, the detection unit 30 detects the following: in the first radar 31A, the Doppler velocity corresponding to the distance r1b (4.70m), that is, the first velocity V1, is 4.0km / h, and the Doppler velocity corresponding to the distance r1a (5.93m), that is, the first velocity V1, is 4.1km / h. Assume that the detection unit 30 detects the following: in the second radar 31B, the Doppler velocity corresponding to the distance r2b (4.10m), that is, the second velocity V2, is 3.62km / h, and the Doppler velocity corresponding to the distance r2a (5.10m), that is, the second velocity V2, is 3.88km / h. The detection unit 30 uses equations (3) and (4) to convert the velocity detected by the second radar 31B into the velocity in the angular direction of the first radar 31A. The Doppler velocity (3.62 km / h) corresponding to the distance r2b (4.10 m) from the second radar 31B can be converted to 3.9975 km / h and 3.2782 km / h. The Doppler velocity (3.88 km / h) corresponding to the distance R2a (5.15 m) from the second radar 31B can be converted to 3.6675 km / h and 4.1048 km / h. Figure 23The table shows the absolute value of the difference between the first speed V1 and the second speed V2 after conversion.

[0124] The closest value to the first speed of 4.0 km / h corresponding to 4.70 m of the first radar 31A is the second speed of 3.9975 km / h corresponding to 4.1 m of the second radar 31B. Therefore, it can be determined that object 50B is located at candidate point 60B, the intersection of 4.70 m of the first radar 31A and 4.10 m of the second radar 31B. Furthermore, the closest value to the first speed of 4.1 km / h corresponding to 5.93 m of the first radar 31A is 4.1048 km / h, the second speed corresponding to 5.1 m of the second radar 31B. Therefore, it can be determined that object 50A is located at candidate point 60A, the intersection of 4.10 m of the first radar 31A and 5.10 m of the second radar 31B.

[0125] Therefore, if Figure 17 As shown, if the determination in step S20 is "No," the detection unit 30 calculates the angles of all candidate points (step S60), calculates the velocities of all candidate points (step S70), and finds candidate points where objects are located (step S80). Furthermore, the detection unit 30 determines whether each object is outside the detection target area DEC (step S40). The subsequent processing is the same as described above.

[0126] Then, if Figure 18 As shown, the detection unit 30 uses a radar that is relatively close to the object 50 to measure the Doppler velocity of the object 50 (step S100). In this case, velocity correction is not performed. Figure 19 In the example shown in (b), since the first radar 31A is close to the object 50, the Doppler velocity is measured using the first radar 31A. Next, the detection unit 30 determines whether the object 50 is approaching the RTG crane 10 based on the Doppler velocity (step S110). If it is determined in step S110 that the object 50 is not approaching the RTG crane 10, the process ends. Figure 18 The process shown, again from Figure 17 On the other hand, in step S110, when it is determined that the object 50 is approaching the RTG crane, the RTG crane 10 decelerates or stops (step S120). Then, the process ends. Figure 18 The processing shown.

[0127] Furthermore, in the above embodiment, the matching Doppler velocities of the first radar 31A and the second radar 31B are utilized to select the intersection point where an object is located from among all intersection points. Instead of the Doppler velocities, the matching intensity of the received radio waves reflected from the object can be utilized. In other words, the received radio wave intensity can be used as the measurement parameter. Since the received radio wave intensity varies with distance, it is necessary to convert the received radio wave intensity based on distance, similar to the conversion of the Doppler velocity.

[0128] Next, the operation and effects of the RTG crane 10 according to this embodiment will be described.

[0129] The RTG crane 10 is equipped with a detection unit 30 that detects objects on the forward side of the crane in the travel direction. Therefore, if an object that poses an obstacle is present on the forward side, the detection unit 30 can detect it. The detection unit 30 includes at least a first radar 31A and a second radar 31B that use millimeter waves or quasi-millimeter waves to detect objects within a detection range DS. The radars 31A and 31B transmit radio waves, such as millimeter waves or quasi-millimeter waves, to the surrounding area and detect objects based on the intensity of the reflected waves. Furthermore, the detection unit 30 can also detect the angle of an object using the first and second radars 31A and 31B. Furthermore, the detection unit 30 obtains the distance from the first and second radars 31A and 31B to the object and, based on this distance, calculates a candidate point for the object to be detected. The detection unit 30 then determines whether an object is present at the candidate point based on the difference between the measurement parameters of the candidate point measured by the first radar 31A and the measurement parameters of the candidate point measured by the second radar 31B. This can prevent erroneous detection of an object at a candidate point where no object actually exists, thereby improving object detection accuracy.

[0130] The measurement parameter may be the Doppler velocity, thereby enabling high-precision calculation of whether an object exists at a candidate point.

[0131] The detection unit 30 can convert the first velocity V1 measured by the first radar 31A and the second velocity V2 measured by the second radar 31B into velocity components in the angular directions of the radars 31A and 31B. This allows for accurate calculation of whether an object exists at the candidate point.

[0132] The detection unit 30 can determine whether the object is approaching or moving away from the detection unit 30. This allows the operation of the RTG crane 10 to be appropriately changed when the object is approaching or moving away.

[0133] The detection unit 30 may include the first radar 31A and the second radar 31B provided for one traveling unit 15. In this case, an object existing near the one traveling unit 15 can be detected with high accuracy.

[0134] An object detection system 120 for an RTG crane according to one aspect of the present invention includes a detection unit 30 for detecting an object existing on the forward side of the travel direction of the RTG crane 10 traveling on a travel path. The detection unit 30 includes at least a first radar 31A and a second radar 31B for detecting objects within a detection range DS using millimeter waves or quasi-millimeter waves. The detection unit 30 obtains the distance from the first radar 31A and the second radar 31B to the object, calculates a candidate point for the object to be detected based on the distance, and determines whether the object exists at the candidate point based on the difference between the measurement parameters of the candidate point measured by the first radar 31A and the measurement parameters of the candidate point measured by the second radar 31B.

[0135] According to the object detection system 120 of the RTG crane, the same operation and effects as those of the above-mentioned RTG crane 10 can be obtained.

[0136] In addition, you can replace Figure 16 In the configuration shown, travel units 15A and 15B are provided at one end and the other end of the RTG crane 10. The first radar 31A is provided on the travel unit 15A at one end, and the second radar 31B is provided on the travel unit 15B at the other end. This reduces the number of radars in the RTG crane 10.

[0137] Furthermore, in the above-described embodiment, the Doppler velocity is used to determine whether the vehicle is approaching or moving away. However, a more accurate determination may be made by combining the velocity of the RTG crane 10 .

[0138] Explanation of symbols

[0139] 10-RTG crane, 15A, 15B-traveling unit, 30-detection unit, 31-radar, 31A-first radar, 31B-second radar, 32-adjustment unit, 37-adjustment component, 111-information processing unit (detection unit), 120-object detection system.

Claims

1. An RTG crane traveling on a travel path, the RTG crane comprising: A traveling portion, which travels in the direction of travel; and a detection unit that detects an object that is present on the forward side of the traveling direction, The detection unit includes at least a first radar and a second radar for detecting the object within a detection range using millimeter waves or quasi-millimeter waves. The detection unit obtains the distance from the first radar and the second radar to the object, and calculates a candidate point of the object to be detected based on the distance. The detection unit determines whether the object exists at the candidate point based on a difference between a measurement parameter of the candidate point measured by the first radar and a measurement parameter of the candidate point measured by the second radar.

2. The RTG crane according to claim 1, wherein: The measurement parameter is Doppler velocity.

3. The RTG crane according to claim 2, wherein: The detecting unit converts the first Doppler velocity measured by the first radar and the second Doppler velocity measured by the second radar into velocity components in respective radar angular directions.

4. The RTG crane according to claim 1, wherein: The detection section determines whether the object is approaching or moving away from the detection section.

5. The RTG crane according to claim 1, wherein: The detection unit includes the first radar and the second radar provided for one traveling unit.

6. The RTG crane according to claim 1, wherein: The traveling portion is provided on one end side and the other end side of the RTG crane. The first radar is installed on the traveling portion on the one end side, and the second radar is installed on the traveling portion on the other end side.

7. An object detection system for an RTG crane, comprising: a detection unit for detecting an object existing on a forward side of a traveling direction of the RTG crane traveling on a traveling path; The detection unit includes at least a first radar and a second radar for detecting the object within a detection range using millimeter waves or quasi-millimeter waves. The detection unit obtains the distance from the first radar and the second radar to the object, and calculates a candidate point of the object to be detected based on the distance. The detection unit determines whether the object exists at the candidate point based on a difference between a measurement parameter of the candidate point measured by the first radar and a measurement parameter of the candidate point measured by the second radar.

Images