Engine type industrial vehicle

Abstract

The invention provides an engine-type industrial vehicle which appropriately suppresses contact with an object. A forklift is provided with: an engine; a power transmission mechanism that transmits the driving force of the engine to the drive wheels; a main control device that adjusts the driving force transmitted to the driving wheels; and an object detection unit that detects the position of an object present in the traveling direction of the vehicle body. The main control device derives a predicted trajectory that is a trajectory through which the vehicle body is predicted to pass. The main control device sets the vehicle speed upper limit value when the object is located within the predicted trajectory and the traveling direction of the vehicle body is the direction approaching the object. The main control device is configured so that the vehicle speed of the vehicle body does not exceed the vehicle speed upper limit value by performing at least one of a control for acting a force in a direction obstructing the travel of the vehicle body and a control for cutting off the driving force to the drive wheels.

Description

[0001] This application is a divisional application. The application number of the original application is 202111505187.7, the application date is December 10, 2021, and the name of the invention is “Engine-type industrial vehicle”. Technical Field

[0002] The present disclosure relates to engine-powered industrial vehicles. Background Art

[0003] The engine-type industrial vehicle disclosed in Patent Document 1 includes a sensor for detecting an object, a control device, and an engine. The engine-type industrial vehicle travels by the driving force of the engine. When the sensor detects that an object exists within a set range, the control device controls the engine-type industrial vehicle to stop. The set range is the longest distance until the engine-type industrial vehicle stops.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2015 / 147149 Summary of the invention

[0007] Problem that the invention aims to solve

[0008] In the engine-type industrial vehicle disclosed in Patent Document 1, when an object exists within a set range, control is performed to stop the engine-type industrial vehicle. It is desired to further appropriately suppress the contact between the engine-type industrial vehicle and the object.

[0009] Solutions for solving problems

[0010] An engine-type industrial vehicle that solves the above-mentioned problem comprises: an engine; a power transmission mechanism that transmits the driving force of the above-mentioned engine to the driving wheels; a main control device that adjusts the above-mentioned driving force transmitted to the above-mentioned driving wheels; an object detection unit that detects the position of an object existing in the traveling direction of the vehicle body; an estimated trajectory derivation unit that derives an estimated trajectory as a trajectory that the above-mentioned vehicle body is expected to pass; and a vehicle speed upper limit setting unit that sets the vehicle speed upper limit when the above-mentioned object detected by the above-mentioned object detection unit is located in the above-mentioned estimated trajectory and the traveling direction of the above-mentioned vehicle body is a direction approaching the above-mentioned object, thereby limiting the vehicle speed of the above-mentioned vehicle body, wherein the above-mentioned main control device is configured to control the vehicle speed of the above-mentioned vehicle body not to exceed the above-mentioned vehicle speed upper limit by performing at least one of control of causing a force to act in a direction that hinders the travel of the above-mentioned vehicle body and control of cutting off the above-mentioned driving force to the above-mentioned driving wheels.

[0011] The main control device imposes a speed limit when the object is within the expected trajectory and the vehicle body is moving in a direction approaching the object. The expected trajectory is a trajectory that the vehicle body is expected to pass. When the object is within the expected trajectory, the engine-type industrial vehicle may come into contact with the object due to the movement of the vehicle body. By imposing a speed limit when the object is within the expected trajectory, the contact between the engine-type industrial vehicle and the object can be appropriately suppressed.

[0012] The engine-type industrial vehicle may include a brake mechanism operated by the main control device, and the main control device may be configured to operate the brake mechanism so that the vehicle speed of the vehicle body does not exceed the vehicle speed upper limit.

[0013] The main control device can decelerate the vehicle body by operating the brake mechanism. The brake mechanism can adjust the deceleration of the vehicle body.

[0014] Regarding the engine-type industrial vehicle, the main control device may be configured to perform two types of control: control of causing a force to act in a direction that hinders the travel of the vehicle body; and control of cutting off the driving force to the drive wheels.

[0015] Effects of the Invention

[0016] According to the present invention, contact with an object can be appropriately suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a three-dimensional diagram of a forklift.

[0018] Figure 2 This is a schematic diagram of a forklift.

[0019] Figure 3 : is a flowchart showing the processing performed by the obstacle detection device.

[0020] Figure 4 is a diagram schematically showing an automatic deceleration area and an estimated trajectory.

[0021] Figure 5 The diagram schematically shows a predicted trajectory when the vehicle speed of the forklift is increased.

[0022] Figure 6 Schematically shows a predicted trajectory of a forklift when it is turning.

[0023] Figure 7 The diagram schematically shows a predicted trajectory when the vehicle speed of the forklift is increased while the forklift is turning.

[0024] Figure 8This is the state transition diagram of the travel stop control.

[0025] Fig. 9 This is a table showing the correspondence between each state to which the main control device transitions and the vehicle speed upper limit value and the acceleration upper limit value.

[0026] Fig.10 It is the state transition diagram of the speed limit control.

[0027] Fig.11 It is a schematic structural diagram of a forklift according to a modified example.

[0028] Description of Reference Numerals

[0029] 10 ... a forklift as an engine-type industrial vehicle, 31 ... a main control device as an estimated trajectory derivation unit and a vehicle speed upper limit setting unit, 51 ... an object detection unit, 61 ... an engine, 70 ... a power transmission mechanism, 100 ... a braking mechanism. DETAILED DESCRIPTION

[0030] Hereinafter, an embodiment of an engine-type industrial vehicle will be described.

[0031] like Figure 1 As shown, a forklift 10 as an engine-type industrial vehicle includes a vehicle body 11 , two drive wheels 12 , 13 , two steering wheels 14 , and a cargo handling device 20 .

[0032] The vehicle body 11 includes a head guard 15 provided above a driver's seat. In the following description, front, rear, left, and right refer to the front, rear, left, and right of the forklift 10 .

[0033] The driving wheels 12 and 13 are arranged at the front lower part of the vehicle body 11. The two driving wheels 12 and 13 are arranged to be separated from each other in the vehicle width direction.

[0034] The two steering wheels 14 are disposed at a rear lower portion of the vehicle body 11. The two steering wheels 14 are disposed apart from each other in the vehicle width direction.

[0035] The cargo handling device 20 includes a mast 21, a pair of forks 22, and a lift cylinder 23. The mast 21 is provided at the front portion of the vehicle body 11. The forks 22 are provided so as to be able to be raised and lowered together with the mast 21. The cargo is loaded on the forks 22. The lift cylinder 23 is a hydraulic cylinder. The mast 21 is raised and lowered by extending and retracting the lift cylinder 23. The forks 22 are raised and lowered along with the raising and lowering of the mast 21. The forklift 10 of this embodiment is a forklift that performs a traveling action and a cargo handling action by an operator's operation.

[0036] like Figure 2As shown, the forklift 10 includes a main control device 31, an accelerator pedal 16, an acceleration sensor 34, a steering rod 17, a steering sensor 35, a tire angle sensor 36, a lift height sensor 37, a weight sensor 38, a travel system 60, a cargo handling system 90, an object detection unit 51 and a bus 40.

[0037] The main control device 31 includes a processor 32 and a storage unit 33. As the processor 32, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), or a DSP (Digital Signal Processor) can be used. The storage unit 33 includes a RAM (Random Access Memory) and a ROM (Read Only Memory). The storage unit 33 stores a program for operating the forklift 10. It can be said that the storage unit 33 stores a program code or an instruction configured to cause the processor 32 to execute a process. The storage unit 33, that is, a computer-readable medium, includes all available media that can be accessed by a general-purpose or special-purpose computer. The main control device 31 can also be composed of a hardware circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). The main control device 31 as a processing circuit can include one or more processors that operate according to a computer program, one or more hardware circuits such as an ASIC or FPGA, or a combination thereof.

[0038] The accelerator sensor 34 detects the amount of operation of the accelerator pedal 16. The amount of operation of the accelerator pedal 16 can also be referred to as the accelerator opening. The accelerator sensor 34 outputs an electrical signal corresponding to the accelerator opening to the main control device 31. The main control device 31 can recognize the accelerator opening through the electrical signal from the accelerator sensor 34.

[0039] The direction sensor 35 detects the operation direction of the direction bar 17. The direction bar 17 indicates the direction of travel of the vehicle body 11. The direction of travel of the vehicle body 11 can also be said to be the direction of travel of the forklift 10. The direction sensor 35 detects whether the direction bar 17 is operated in the direction indicating forward movement or in the direction indicating reverse movement, with the neutral position as a reference. The direction sensor 35 outputs an electrical signal corresponding to the operation direction of the direction bar 17 to the main control device 31. The main control device 31 can recognize the operation direction of the direction bar 17 through the electrical signal from the direction sensor 35. The main control device 31 can grasp whether the operator has instructed to move forward, instructed to move backward, or instructed neither.

[0040] The tire angle sensor 36 detects the steering angle of the steering wheel 14. The tire angle sensor 36 outputs an electrical signal corresponding to the steering angle to the main control device 31. The main control device 31 can recognize the steering angle through the electrical signal from the tire angle sensor 36.

[0041] The lifting height sensor 37 detects the lifting height of the cargo handling device 20. The lifting height of the cargo handling device 20 refers to the height from the road surface to the fork 22. The lifting height sensor 37 is, for example, a reel sensor. The lifting height sensor 37 outputs an electrical signal corresponding to the lifting height to the main control device 31. The main control device 31 can recognize the lifting height of the cargo handling device 20 through the electrical signal from the lifting height sensor 37.

[0042] The weight sensor 38 detects the weight of the cargo loaded on the cargo handling device 20. The weight sensor 38 is, for example, a pressure sensor that detects the hydraulic pressure of the lift cylinder 23. The weight sensor 38 outputs an electrical signal corresponding to the weight of the cargo to the main control device 31. The main control device 31 can recognize the weight of the cargo through the electrical signal from the weight sensor 38.

[0043] The travel system 60 is a mechanism for moving the vehicle body 11 , and includes an engine 61 , an output shaft 63 , a rotation speed sensor 64 , a power transmission mechanism 70 , a differential device 80 , an axle 81 , a vehicle speed sensor 82 , and a travel control device 83 .

[0044] The engine 61 is a driving source for the travel action and cargo loading and unloading action of the forklift 10. The engine 61 of this embodiment is a gasoline engine that uses gasoline as fuel. The engine 61 is equipped with a throttle actuator 62. The throttle actuator 62 adjusts the throttle opening. By adjusting the throttle opening by the throttle actuator 62, the amount of air to the engine 61 is adjusted. As a result, the rotation speed of the engine 61 is controlled.

[0045] The output shaft 63 is connected to the engine 61. The output shaft 63 is driven by the engine 61 to rotate.

[0046] The rotation speed sensor 64 is provided on the output shaft 63. The rotation speed sensor 64 detects the rotation speed of the engine 61. The rotation speed of the engine 61 refers to the rotation speed of the output shaft 63. The rotation speed sensor 64 outputs an electrical signal corresponding to the rotation speed of the output shaft 63 to the travel control device 83.

[0047] The power transmission mechanism 70 transmits the driving force of the engine 61 to the drive wheels 12 and 13. The power transmission mechanism 70 includes a torque converter 71, a transmission 72, and a solenoid valve 79.

[0048] The torque converter 71 is connected to the output shaft 63. The driving force of the engine 61 is transmitted to the torque converter 71 via the output shaft 63. The torque converter 71 includes a pump connected to the output shaft 63 and a turbine. In the torque converter 71, the turbine is rotated by the hydraulic oil discharged from the pump.

[0049] The transmission 72 includes an input shaft 73 , a forward clutch 74 , a forward gear train 75 , a reverse clutch 76 , a reverse gear train 77 , and an output shaft 78 .

[0050] The input shaft 73 is connected to the torque converter 71 . The driving force is transmitted from the torque converter 71 to the transmission 72 via the input shaft 73 .

[0051] The forward clutch 74 is provided on the input shaft 73. The forward gear train 75 is provided between the forward clutch 74 and the output shaft 78. The forward clutch 74 is switched to a connected state or a disconnected state. The connected state is a state in which the input shaft 73 and the forward gear train 75 are connected. The disconnected state is a state in which the input shaft 73 and the forward gear train 75 are disconnected. When the input shaft 73 and the forward gear train 75 are connected via the forward clutch 74, the driving force is transmitted from the input shaft 73 to the forward gear train 75. The driving force transmitted to the forward gear train 75 is transmitted to the output shaft 78. It can be said that when the forward clutch 74 is connected to the forward gear train 75, the driving force of the engine 61 is transmitted to the output shaft 78. When the forward clutch 74 and the forward gear train 75 are disconnected, the driving force is not transmitted from the input shaft 73 to the forward gear train 75.

[0052] The reverse clutch 76 is provided on the input shaft 73. The reverse gear train 77 is provided between the reverse clutch 76 and the output shaft 78. The reverse clutch 76 is switched to a connected state or a disconnected state. The connected state is a state in which the input shaft 73 and the reverse gear train 77 are connected. The disconnected state is a state in which the input shaft 73 and the reverse gear train 77 are disconnected. When the input shaft 73 and the reverse gear train 77 are connected via the reverse clutch 76, the driving force is transmitted from the input shaft 73 to the reverse gear train 77. The driving force transmitted to the reverse gear train 77 is transmitted to the output shaft 78. It can be said that when the reverse clutch 76 and the reverse gear train 77 are connected, the driving force of the engine 61 is transmitted to the output shaft 78. When the reverse clutch 76 and the reverse gear train 77 are disconnected, the driving force is not transmitted from the input shaft 73 to the reverse gear train 77.

[0053] Hydraulic clutches are used as the forward clutch 74 and the reverse clutch 76. As the hydraulic clutch, for example, a wet multi-plate clutch can be cited.

[0054] When the forward clutch 74 or the reverse clutch 76 is in the connected state, the driving force is transmitted to the output shaft 78. The output shaft 78 is rotated by the driving force transmitted from the forward clutch 74 or the reverse clutch 76.

[0055] One solenoid valve 79 is provided corresponding to each of the forward clutch 74 and the reverse clutch 76. The solenoid valve 79 controls the supply and discharge of the working oil to the forward clutch 74 and the reverse clutch 76. The solenoid valve 79 supplies and discharges the working oil by the amount of current supplied to the solenoid. The connection state and disconnection state of the clutches 74 and 76 are switched by the supply and discharge of the working oil by the solenoid valve 79.

[0056] When the direction lever 17 indicates forward movement, the forward clutch 74 is connected to the forward gear train 75. When the direction lever 17 indicates reverse movement, the reverse clutch 76 is connected to the reverse gear train 77. When the direction lever 17 indicates neutral movement, both the forward clutch 74 and the reverse clutch 76 are disconnected.

[0057] The differential device 80 is connected to the output shaft 78. The axle 81 is connected to the differential device 80. The axle 81 is connected to the drive wheels 12 and 13. The axle 81 rotates by the rotation of the output shaft 78. The drive wheels 12 and 13 rotate by the rotation of the axle 81, thereby the forklift 10 travels. If the forward clutch 74 and the forward gear train 75 are connected, the forklift 10 moves forward. If the reverse clutch 76 and the reverse gear train 77 are connected, the forklift 10 moves backward.

[0058] The vehicle speed sensor 82 is a sensor for detecting the vehicle speed of the vehicle body 11. The vehicle speed of the vehicle body 11 can also be referred to as the vehicle speed of the forklift 10. The vehicle speed sensor 82 is provided, for example, on the output shaft 78 or the axle 81. The vehicle speed sensor 82 outputs a pulse signal corresponding to the vehicle speed of the vehicle body 11 to the travel control device 83.

[0059] The travel control device 83 is an engine control unit that controls the engine 61. The hardware configuration of the travel control device 83 is, for example, the same as that of the main control device 31. The travel control device 83 adjusts the throttle opening by controlling the throttle actuator 62. The driving force of the engine 61 is adjusted by adjusting the throttle opening. The travel control device 83 controls the solenoid valve 79 that switches the connection state and disconnection state of the clutches 74 and 76. As a result, the connection state and disconnection state of the clutches 74 and 76 are switched.

[0060] The cargo handling system 90 is a mechanism for operating the cargo handling device 20. The cargo handling system 90 includes an oil tank 91 storing hydraulic oil, a hydraulic pump 92, and a hydraulic mechanism 93.

[0061] The hydraulic pump 92 is driven by the engine 61. The hydraulic pump 92 draws hydraulic oil from the oil tank 91. The drawn hydraulic oil is supplied to the hydraulic mechanism 93.

[0062] The hydraulic mechanism 93 includes a control valve. The control valve controls the supply and discharge of the hydraulic oil to the hydraulic device. As the hydraulic device, the lifting cylinder 23 and the tilting cylinder for tilting the cargo handling device 20 can be listed. The cargo handling device 20 is operated by the supply or discharge of the hydraulic oil. In addition, as the hydraulic device, any hydraulic device equipped with the forklift 10 can be used, and it can also be a hydraulic device equipped with the vehicle body 11. As the hydraulic device equipped with the vehicle body 11, for example, the clutches 74 and 76 can be listed.

[0063] The object detection unit 51 includes: a stereo camera 52; an obstacle detection device 55 that detects an object based on an image captured by the stereo camera 52; and an alarm device 58. Figure 1 As shown in the figure, the stereo camera 52 is arranged on the roof guard 15. The stereo camera 52 is arranged so as to be able to overlook the road surface on which the forklift 10 is traveling from above the forklift 10. The stereo camera 52 of this embodiment takes a picture of the rear of the forklift 10. Therefore, the object detected by the obstacle detection device 55 is the object behind the forklift 10. The alarm device 58 and the obstacle detection device 55 may be unitized with the stereo camera 52 and arranged on the roof guard 15 together with the stereo camera 52. In addition, the alarm device 58 and the obstacle detection device 55 may be arranged at a position different from the roof guard 15.

[0064] like Figure 2 As shown, the stereo camera 52 includes two cameras 53 and 54. The cameras 53 and 54 use, for example, a CCD image sensor or a CMOS image sensor. The cameras 53 and 54 are arranged so that their optical axes are parallel to each other. The two cameras 53 and 54 are separated from each other, so that the same object is misaligned in the images taken by the two cameras 53 and 54. In detail, when the same object is photographed, the object presented in the images taken by the two cameras 53 and 54 will have a pixel misalignment corresponding to the distance between the two cameras 53 and 54. As the stereo camera 52 of this embodiment, a wide-angle stereo camera with a horizontal viewing angle of more than 100° is used, but a non-wide-angle stereo camera may also be used as the stereo camera 52.

[0065] The obstacle detection device 55 includes a processor 56 and a storage unit 57. As the processor 56, for example, a CPU, a GPU, or a DSP can be used. The storage unit 57 includes a RAM and a ROM. The storage unit 57 stores various programs for detecting objects based on the images captured by the stereo camera 52. It can be said that the storage unit 57 stores program codes or instructions configured to cause the processor 56 to perform processing. The storage unit 57, that is, the computer-readable medium includes all available media that can be accessed by a general-purpose or special-purpose computer. The obstacle detection device 55 can also be composed of hardware circuits such as ASIC and FPGA. The obstacle detection device 55 as a processing circuit may include one or more processors that act according to a computer program, one or more hardware circuits such as ASIC or FPGA, or a combination thereof.

[0066] The obstacle detection device 55 detects an object existing around the forklift 10 by repeatedly performing the following processing in a predetermined control cycle. In addition, the obstacle detection device 55 derives the position of the detected object. The position of the object refers to the relative position between the forklift 10 and the object.

[0067] like Figure 3 As shown, in step S100 , the obstacle detection device 55 acquires images from the cameras 53 and 54 of the stereo camera 52 .

[0068] Next, in step S110, the obstacle detection device 55 obtains a parallax image by performing stereo processing. A parallax image is an image in which parallax [px] is associated with a pixel. The parallax image is not an image that must be displayed, but is data indicating that each pixel in the parallax image is associated with a parallax. The parallax can be obtained by comparing the images captured by the two cameras 53 and 54 provided by the stereo camera 52 and deriving the difference in the number of pixels between the images for the same feature points presented in each image. The obstacle detection device 55 uses one of the images captured by the two cameras 53 and 54 as a reference image and the other as a comparison image, and extracts the most similar pixel of the comparison image for each pixel of the reference image. The obstacle detection device 55 calculates the difference in the number of pixels between the pixels of the reference image and the pixels of the comparison image as the parallax. In this way, a parallax image in which each pixel of the reference image is associated with a parallax can be obtained. In addition, a feature point refers to a portion that can be recognized as a boundary, such as an edge of an object. The feature point can be detected based on brightness information, etc.

[0069] Next, in step S120, the obstacle detection device 55 derives the coordinates of the feature points in the world coordinate system, which is a coordinate system in the actual space. The world coordinate system is a coordinate system in which the axis extending in the vehicle width direction of the forklift 10 in the horizontal direction is the X-axis, the axis orthogonal to the X-axis in the horizontal direction is the Y-axis, and the axis extending in the vertical direction is the Z-axis when the forklift 10 is located on a horizontal plane. The coordinates of the feature points are derived as follows: based on the baseline length of the stereo camera 52, the focal length of the stereo camera 52, and the parallax image obtained in step S110, the coordinates of the feature points in the camera coordinate system are derived, and then the coordinates are converted into coordinates in the world coordinate system. In addition, as Figure 1 As shown, the X-axis, Y-axis, and Z-axis are indicated by arrows X, Y, and Z.

[0070] like Figure 3 As shown, in step S130, the obstacle detection device 55 extracts the object by clustering the feature points. The obstacle detection device 55 regards a set of feature points that are assumed to represent the same object among the feature points that represent a part of the object as one point group, and extracts the point group as an object. The obstacle detection device 55 clusters the feature points within a specified range as one point group based on the coordinates of the feature points in the world coordinate system derived in step S120. The obstacle detection device 55 regards the clustered point group as one object. In addition, the clustering of the feature points performed in step S130 can be performed by various methods.

[0071] Next, in step S140, the obstacle detection device 55 derives the coordinates of the object in the world coordinate system. The coordinates of the object can be derived based on the coordinates of the feature points that constitute the point group. The coordinates of the object in the world coordinate system represent the relative position of the forklift 10 and the object. In detail, the X coordinate in the coordinates of the object in the world coordinate system represents the distance from the origin to the left and right direction of the object, and the Y coordinate represents the distance from the origin to the front and back direction of the object. The origin is, for example, the coordinates where the X coordinate and the Y coordinate are set to the configuration position of the stereo camera 52 and the Z coordinate is set to the road surface. The Euclidean distance from the configuration position of the stereo camera 52 to the object can also be derived based on the X coordinate and the Y coordinate. The Z coordinate in the coordinates of the object in the world coordinate system represents the height of the object from the road surface.

[0072] Next, in step S150, the obstacle detection device 55 determines whether the object is a person or an obstacle other than a person. Whether the object is a person can be determined by various methods. In the present embodiment, the obstacle detection device 55 performs a human detection process on the image captured by any one of the two cameras 53 and 54 of the stereo camera 52. The obstacle detection device 55 converts the coordinates of the object in the world coordinate system obtained in step S140 into camera coordinates, and converts the camera coordinates into the coordinates of the image captured by the cameras 53 and 54. In the present embodiment, the obstacle detection device 55 converts the coordinates of the object in the world coordinate system into the coordinates of the reference image. The obstacle detection device 55 performs a human detection process on the coordinates of the object in the reference image. For example, the human detection process is performed using feature extraction and a human determiner that has been machine-learned in advance. As feature extraction, for example, a method of extracting feature quantities of local areas in an image such as HOG: Histogram of Oriented Gradients feature quantities and Haar-Like feature quantities can be cited. As a human determiner, for example, a device that has performed machine learning using a supervised learning model can be used. As a supervised learning model, for example, a support vector machine, a neural network, naive Bayes, deep learning, a decision tree, etc. can be used. As supervised data for machine learning, image-specific components such as shape elements and appearance elements of a person extracted from an image can be used. As shape elements, for example, the size or outline of a person can be listed. As appearance elements, for example, light source information, texture information, camera information, etc. can be listed. Light source information includes information related to reflectivity, shadows, etc. Texture information includes color information, etc. Camera information includes information related to image quality, resolution, viewing angle, etc.

[0073] The alarm device 58 is a device for giving an alarm to the operator of the forklift 10. Examples of the alarm device 58 include a buzzer for giving an alarm by sound, a lamp for giving an alarm by light, or a combination thereof.

[0074] like Figure 2 As shown, the main control device 31, the travel control device 83, and the object detection unit 51 are configured to be able to obtain information from each other through the bus 40. The main control device 31, the travel control device 83, and the object detection unit 51 obtain information from each other by communicating in accordance with a vehicle communication protocol such as CAN: Controller Area Network (controller local area network) or LIN: Local Interconnect Network (local interconnect network).

[0075] The main control device 31 derives the vehicle speed of the vehicle body 11. The vehicle speed of the vehicle body 11 can be derived by using the detection result of the vehicle speed sensor 82, the gear ratio, the outer diameter of the drive wheels 12 and 13, the steering angle detected by the tire angle sensor 36, etc. The detection result of the vehicle speed sensor 82 can be obtained from the travel control device 83. The gear ratio and the outer diameter of the drive wheels 12 and 13 only need to be stored in the storage unit 33 in advance. In addition, the main control device 31 also derives the moving direction of the vehicle body 11 together with the vehicle speed of the vehicle body 11. The moving direction of the vehicle body 11 refers to any one of the forward direction and the backward direction. In addition, in the present embodiment, the vehicle speed represents the absolute value of the vehicle speed.

[0076] The main control device 31 activates the alarm device 58 by sending an alarm command via the bus 40. Specifically, the object detection unit 51 includes an operating unit that activates the alarm device 58, and the operating unit activates the alarm device 58 when receiving the alarm command.

[0077] Next, the vehicle speed control performed in the forklift 10 will be described.

[0078] The main control device 31 performs automatic deceleration control on the forklift 10 based on the position of the object detected by the object detection unit 51 and the type of the object. The type of the object refers to either a person or an obstacle other than a person. In the following description, an obstacle refers to an object other than a person.

[0079] like Figure 4 As shown in FIG. 1 , an automatic deceleration area AA2 for automatic deceleration control is set within the detectable range of the object by the object detection unit 51. The detectable range of the object by the object detection unit 51 can also be said to be the photographable range of the stereo camera 52. In the present embodiment, the automatic deceleration area AA2 is the same area as the detectable range of the object by the object detection unit 51. The automatic deceleration area AA2 is an area extending from the configuration position of the stereo camera 52 to the rear of the forklift 10 and in the vehicle width direction of the forklift 10. The automatic deceleration area AA2 is an area defined by the X coordinate and the Y coordinate in the world coordinate system.

[0080] The main control device 31 derives the expected trajectory T of the vehicle body 11. The expected trajectory T refers to the trajectory that the vehicle body 11 is expected to pass. In the present embodiment, when the moving direction of the vehicle body 11 is the backward direction, for example, when the operator operates the direction lever 17 in the direction indicating the backward movement, the main control device 31 derives the expected trajectory T that the vehicle body 11 is expected to pass. The expected trajectory T of the vehicle body 11 can also be said to be the expected trajectory T of the forklift 10.

[0081] The estimated trajectory T can be derived from the steering angle of the steering wheel 14 and the dimensional information of the forklift 10. The dimensional information of the forklift 10 includes the dimension [mm] from the central axis of the driving wheels 12 and 13 to the rear end of the vehicle body 11, the wheelbase [mm], and the vehicle width [mm]. The dimensional information of the forklift 10 is known information, and therefore can be stored in advance in the storage unit 33 of the main control device 31. The estimated trajectory T is a trajectory between the trajectory LT passed by the left end LE of the vehicle body 11 and the trajectory RT passed by the right end RE of the vehicle body 11. The main control device 31 derives the X coordinate and the Y coordinate of the estimated trajectory T extending to the rear of the forklift 10 in the world coordinate system.

[0082] like Figure 4 and Figure 5 As shown in FIG. 1 , when the forklift 10 is moving straight, the estimated trajectory T is a trajectory extending straight from the forklift 10 in the backward direction. Figure 6 and Figure 7 As shown in FIG. 1 , when the forklift 10 is turning, the predicted trajectory T is a trajectory that curves from the forklift 10 toward the backward direction. When the forklift 10 is turning right, the predicted trajectory T extends to the right, and when the forklift 10 is turning left, the predicted trajectory T extends to the left. It can be said that the main control device 31 derives the predicted trajectory T that extends toward the turning direction when the forklift 10 is turning.

[0083] Figure 5 The forklift shown is 10 Figure 4 The vehicle speed of the forklift 10 in the state shown is high. Figure 7 The forklift shown is 10 Figure 6 The forklift 10 shown has a high speed. Figures 4 to 7 As shown, the higher the vehicle speed of the vehicle body 11, the more the main control device 31 extends the estimated trajectory T in the direction of travel. In the present embodiment, the trajectory derivation threshold value YT is changed according to the vehicle speed. The trajectory derivation threshold value YT is a threshold value set for the Y coordinate in the world coordinate system, and the higher the vehicle speed, the threshold value YT becomes the Y coordinate farther away from the forklift 10. The main control device 31 derives the estimated trajectory T from the forklift 10 to the trajectory derivation threshold value YT. In addition, the higher the vehicle speed of the vehicle body 11, the more the estimated trajectory T is extended in the direction of travel is not limited to the method in which the vehicle speed of the vehicle body 11 and the length of the estimated trajectory T in the direction of travel are in proportional relationship, as long as there is the following correlation: if the vehicle speed of the vehicle body 11 becomes higher, the length of the estimated trajectory T in the direction of travel becomes longer.

[0084] The estimated trajectory T is derived in the automatic deceleration area AA2. In the present embodiment, the main control device 31 functions as an estimated trajectory deriving unit.

[0085] The automatic deceleration control will be described. In addition, the X coordinate and the Y coordinate in the following description are the X coordinate and the Y coordinate in the world coordinate system.

[0086] The automatic deceleration control includes a travel stop control and a vehicle speed limit control. The travel stop control is a control for stopping the forklift 10. The vehicle speed limit control is a control for allowing the forklift 10 to travel at a speed lower than an upper limit value.

[0087] like Figure 8 As shown, in the travel stop control, by setting the state of the main control device 31 to any of the normal control state S10, the pre-travel restriction state S11, the travel restriction state S12, and the travel restriction pre-release state S13, control corresponding to each state is performed.

[0088] like Fig. 9 As shown, the normal control state S10 refers to a state where the vehicle speed limit is not applied. In addition, in the normal control state S10, there is no restriction on acceleration. When the main control device 31 is in the normal control state S10, the main control device 31 calculates the target speed based on the accelerator opening detected by the acceleration sensor 34. The larger the accelerator opening, the larger the target speed. The main control device 31 determines whether to make the forklift 10 move forward or backward based on the operation direction of the steering lever 17. The main control device 31 generates a speed command including information indicating the target speed and information indicating the operation direction of the steering lever 17. The main control device 31 sends the speed command to the travel control device 83. The travel control device 83 controls the engine 61 in a manner that follows the target speed. In detail, the travel control device 83 adjusts the throttle opening by controlling the throttle actuator 62. As a result, the forklift 10 travels at a vehicle speed corresponding to the amount of operation of the accelerator pedal 16 by the operator. In this way, the main control device 31 can control the rotation speed of the engine 61 by sending the rotation speed instruction to the travel control device 83. It can be said that the driving force transmitted to the drive wheels 12 and 13 is adjusted by controlling the rotation speed of the engine 61. It can be said that the main control device 31 can adjust the driving force transmitted to the drive wheels 12 and 13.

[0089] Furthermore, the state where the vehicle speed limit is not applied includes not only a mode where the vehicle speed upper limit is not set, but also a mode where the vehicle speed upper limit is set such that the vehicle speed does not substantially function, such as a mode where the vehicle speed upper limit is set higher than the maximum speed that the forklift 10 can reach. Similarly, the state where the acceleration limit is not applied includes not only a mode where the acceleration upper limit is not set, but also a mode where the acceleration upper limit is set higher than the maximum acceleration that the forklift 10 can reach, such as a mode where the acceleration upper limit is set such that the vehicle speed does not substantially function.

[0090] like Figure 8As shown, when the main control device 31 is in the normal control state S10, if the pre-travel restriction condition is satisfied, the main control device 31 changes to the pre-travel restriction state S11. The pre-travel restriction condition is satisfied when both the following conditions A1 and A2 are satisfied.

[0091] Condition A1: There is someone in the alarm area.

[0092] Condition A2: The forklift 10 is traveling in the reverse direction.

[0093] The warning area is an area in the automatic deceleration area AA2 that is different from the area where the speed limit is implemented. The warning area is an area set so that the warning device 58 can issue an alarm before a person enters the expected trajectory T. The warning area of ​​condition A1 can be the entire automatic deceleration area AA2 except the expected trajectory T, or it can be an area of ​​a specified range extending from the expected trajectory T to the outside of the expected trajectory T.

[0094] Whether the forklift 10 is traveling in the reverse direction can be determined based on the vehicle speed and the traveling direction calculated by the main control device 31. When the traveling direction of the forklift 10 is the reverse direction and the vehicle speed is higher than the stop determination threshold [km / h], the main control device 31 determines that the forklift 10 is traveling in the reverse direction. The stop determination threshold is set to a value that can be regarded as the forklift 10 being stopped. The stop determination threshold can be set to any value from 0 [km / h] to 3.0 [km / h], for example.

[0095] The pre-travel restriction state S11 refers to a state in which an alarm is issued by the alarm device 58. In the pre-travel restriction state S11, the speed limit and the acceleration limit are not applied. In addition, the alarm in the pre-travel restriction state S11 is not issued when the forklift 10 turns back. Turning back refers to the action of switching from forward to reverse or from reverse to forward by operating the direction lever 17. When the detection result of the direction sensor 35 becomes inconsistent with the travel direction of the forklift 10, the main control device 31 sets the turn flag to on. When the main control device 31 changes to the pre-travel restriction state S11 with the turn flag on, the alarm device 58 does not issue an alarm. The turn flag is released, for example, when the main control device 31 changes from the pre-travel restriction state S11 to other states.

[0096] When the main control device 31 is in the pre-running restriction state S11, if the pre-running restriction release condition is satisfied, the main control device 31 transitions to the normal control state S10. The pre-running restriction release condition being satisfied means that at least one of the following conditions B1 and B2 is satisfied.

[0097] Condition B1: There is no person within the predicted trajectory T and the warning area.

[0098] Condition B2: The vehicle is stopped from traveling in the reverse direction and no reverse operation is performed.

[0099] The stop of the travel in the reverse direction means that the speed of the forklift 10 changes from a state higher than the stop determination threshold to a state lower than the stop determination threshold. That is, the forklift 10 that is traveling is stopped. The state in which the reverse operation is not performed means that at least one of the state in which the accelerator pedal 16 is not operated and the detection result of the direction sensor 35 is not the reverse state is established. The state in which the detection result of the direction sensor 35 is not the reverse state means that the detection result of the direction sensor 35 is the neutral state or the forward state.

[0100] When the main control device 31 is in the pre-travel restriction state S11, if the travel restriction condition is satisfied, the main control device 31 shifts to the travel restriction state S12. The travel restriction condition is satisfied when both of the following conditions C1 and C2 are satisfied.

[0101] Condition C1…There is a person within the expected trajectory T.

[0102] Condition C2: The forklift 10 is traveling in the reverse direction.

[0103] Whether condition C1 is satisfied can be determined based on the X and Y coordinates of the person. The estimated trajectory T is defined by the X and Y coordinates, so whether the person is within the estimated trajectory T can be determined based on the X and Y coordinates of the person. Condition C2 is the same as condition A2.

[0104] like Fig. 9 As shown, the travel restriction state S12 is a state in which the forklift 10 in travel is decelerated and stopped by setting the vehicle speed upper limit value to 0. By setting the vehicle speed upper limit value, the vehicle speed limit is imposed on the vehicle body 11. The vehicle speed limit of the vehicle body 11 can also be referred to as the vehicle speed limit of the forklift 10. The main control device 31 performs control to cut off the driving force to the drive wheels 12 and 13. Cutting off the driving force to the drive wheels 12 and 13 is a way to adjust the driving force transmitted to the drive wheels 12 and 13. The main control device 31 cuts off the driving force to the drive wheels 12 and 13 by sending a cut-off instruction to the travel control device 83. When the travel control device 83 receives the cut-off instruction, it controls the power transmission mechanism 70 so that the driving force of the engine 61 is not transmitted to the drive wheels 12 and 13. For example, the travel control device 83 controls the transmission 72 so that the clutches 74 and 76 are not connected to the gear trains 75 and 77, or sets the clutches 74 and 76 to the cut-off state. As a result, the forklift 10 is continuously decelerated due to the travel resistance. When the forklift 10 is traveling on a flat road, the forklift 10 stops. The traveling resistance includes air resistance, rolling resistance, and slope resistance. In the travel restriction state S12, the alarm device 58 issues an alarm.

[0105] like Figure 8 As shown, when the main control device 31 is in the driving restriction state S12, if the driving restriction release condition is satisfied, the main control device 31 shifts to the normal control state S10. The driving restriction release condition being satisfied means that the following condition D1 is satisfied.

[0106] Condition D1: The vehicle is stopped from traveling in the reverse direction and no reverse operation is performed.

[0107] Condition D1 is the same condition as condition B2.

[0108] When the main control device 31 is in the travel restriction state S12, if the travel restriction pre-release condition is satisfied, the main control device 31 shifts to the travel restriction pre-release state S13. The travel restriction pre-release condition being satisfied means that both of the following conditions E1 and E2 are satisfied.

[0109] Condition E1…There is no person within the predicted trajectory T.

[0110] Condition E2: The forklift 10 is traveling in the reverse direction.

[0111] It can be said that condition E1 is satisfied when condition C1 is not satisfied. Condition E2 is the same condition as condition A2.

[0112] like Fig. 9 As shown in FIG. 1 , the travel restriction pre-release state S13 is a state in which the vehicle speed restriction is released but the acceleration restriction is applied. The main control device 31 sets the acceleration upper limit value to AS1 [m / s 2 ], and controls so that the acceleration of the forklift 10 does not exceed AS1. AS1 is a value greater than 0, and is a value lower than the maximum acceleration that the forklift 10 can reach. The main control device 31 allows the acceleration of the forklift 10 below AS1. When an acceleration limit is applied, the main control device 31 controls so that the acceleration of the forklift 10 does not exceed the upper limit of acceleration. For example, the main control device 31 performs acceleration limitation by limiting the increase in the rotation speed of the engine 61. The main control device 31 sends an instruction to the travel control device 83 to limit the increase in the rotation speed of the engine 61. The travel control device 83 controls so that the acceleration of the forklift 10 does not exceed AS1 by limiting the increase in the rotation speed of the engine 61 per unit time. In the travel restriction pre-release state S13, no alarm is issued through the alarm device 58.

[0113] like Figure 8 As shown, when the main control device 31 is in the driving restriction pre-release state S13, if the driving restriction formal release condition is satisfied, the main control device 31 changes to the normal control state S10. The driving restriction formal release condition is satisfied when at least one of the following conditions F1 and F2 is satisfied.

[0114] Condition F1: The vehicle speed of the forklift 10 reaches a value obtained by subtracting a first predetermined value from a target vehicle speed.

[0115] Condition F2 ... No back-off operation has been performed.

[0116] It can be said that the condition F1 is that the speed deviation, which is the difference between the target speed and the speed of the forklift 10, is less than the first predetermined value. In the driving restriction pre-release state S13, the speed following performance of the forklift 10 is reduced due to the acceleration restriction, and the speed of the forklift 10 is not easy to reach the target speed. The first predetermined value is set to determine whether the speed of the forklift 10 has reached the target speed intended by the operator in the state where the acceleration restriction is applied. As the first predetermined value, for example, an arbitrary value can be set from 0.5 [km / h] to 2.0 [km / h].

[0117] When the main control device 31 is in the driving restriction pre-release state S13, if the driving restriction condition is satisfied, the main control device 31 changes to the driving restriction state S12. Similarly, when the main control device 31 is in the normal control state S10, if the driving restriction condition is satisfied, the main control device 31 changes to the driving restriction state S12.

[0118] In addition, as described above, the higher the speed of the vehicle body 11, the longer the main control device 31 will lengthen the expected trajectory T in the direction of travel. When the main control device 31 changes to the travel restriction state S12 and shortens the expected trajectory T in the direction of travel as the speed of the vehicle body 11 decreases, there is a possibility that the person will be outside the expected trajectory T. In this case, regardless of whether the forklift 10 is close to the person or not, the main control device 31 will alternately change between the travel restriction state S12 and the travel restriction pre-release state S13. In order to suppress this situation, when the main control device 31 detects a person existing in the expected trajectory T, the length of the expected trajectory T in the direction of travel, that is, the trajectory derivation threshold value YT, is maintained regardless of the speed of the vehicle body 11. The maintenance of the trajectory derivation threshold value YT is released, for example, when the person is no longer in the expected trajectory T.

[0119] Next, the speed limit control is described. The speed limit control performs different control when the object is a person and when the object is an obstacle. The state transition diagram is the same when the object is a person and when the object is an obstacle, so the state transition diagram is used. Fig.10 The vehicle speed limit control when the object is a person and when the object is an obstacle will be described. First, the vehicle speed limit control when the object is a person will be described.

[0120] like Fig.10As shown, in the vehicle speed limit control, by setting the state of the main control device 31 to any of the restriction release state S21, the pre-restriction start state S22, the restriction start state S23, and the restriction pre-release state S24, control corresponding to each state is performed.

[0121] like Fig. 9 As shown, the restriction release state S21 is a state where the vehicle speed is not restricted. In the restriction release state S21, no restriction is imposed on the acceleration.

[0122] like Fig.10 As shown, when the main control device 31 is in the restriction release state S21, if the pre-restriction start condition is satisfied, the main control device 31 transitions to the pre-restriction start state S22. The pre-restriction start condition is satisfied when both of the following conditions G1 and G2 are satisfied.

[0123] Condition G1: There is a person in the advance warning area in the automatic deceleration area AA2.

[0124] Condition G2: The forklift 10 is traveling in the reverse direction.

[0125] The advance warning area is an area that exists farther from the speed limit area where the speed limit is applied. The speed limit area is an area where the speed limit is applied in the area outside the expected trajectory T within the automatic deceleration area AA2. In the automatic deceleration area AA2, the speed limit is not applied at a position far from the forklift 10. That is, in the automatic deceleration area AA2, the following two areas may exist: the speed limit area where the speed limit is applied; and the area where the speed limit is not applied, which is an area farther from the forklift 10 than the speed limit area. The speed limit area is an area extending from the expected trajectory T to the rear of the expected trajectory T and to the left and right of the expected trajectory T. The speed limit area is determined based on the speed of the forklift 10 and the expected trajectory T. The advance warning area is derived from the speed of the forklift 10 and the speed upper limit value set according to the position of the person. The advance warning area is derived so that the time from the person entering the advance warning area to the person entering the speed limit area becomes a predetermined set time. The predetermined setting time is, for example, 1 second to 3 seconds.

[0126] The pre-limit start state S22 is a state in which an alarm is issued by the alarm device 58. The pre-limit start state S22 can be said to be a state for warning the operator that the speed limit may be imposed before the speed limit is imposed. In the pre-limit start state S22, the speed limit and the acceleration limit are not imposed. In the pre-limit start state S22, similarly to the case of the pre-travel limit state S11, no alarm is issued when the forklift 10 is turned around.

[0127] When the main control device 31 is in the pre-restriction start state S22, if the pre-restriction start release condition is satisfied, the main control device 31 transitions to the restriction release state S21. The pre-restriction start release condition is that at least one of the following conditions H1 and H2 is satisfied.

[0128] Condition H1: No one is in the speed limit area or the advance warning area.

[0129] Condition H2: The vehicle is stopped traveling in the reverse direction and no reverse operation is performed.

[0130] When the main control device 31 is in the pre-restriction start state S22, if the first restriction start condition is satisfied, the main control device 31 transitions to the restriction start state S23. The satisfaction of the first restriction start condition means that both of the following conditions I1 and I2 are satisfied.

[0131] Condition I1: There is a person in the speed limit area in the automatic deceleration area AA2.

[0132] Condition I2: The forklift 10 is traveling in the reverse direction.

[0133] like Fig. 9 As shown, the restriction start state S23 refers to a state in which the forklift 10 is subject to a speed restriction due to the presence of a person in the speed restriction area in the automatic deceleration area AA2. The shorter the distance from the forklift 10 to the person, the lower the speed limit is set. In a storage medium such as the storage unit 33 of the main control device 31 or an external storage device, a mapping is stored that corresponds the speed limit to the distance from the forklift 10 to the person. The main control device 31 sets the mapping value that is the speed limit corresponding to the mapping as the speed limit. In addition, the speed limit is not limited to a mode that decreases in proportion to the shortening of the distance from the forklift 10 to the person, as long as there is a correlation that the speed limit decreases if the distance from the forklift 10 to the person becomes shorter. In the case where there are multiple people in the speed restriction area in the automatic deceleration area AA2, the speed limit is determined according to the position of the person closest to the forklift 10.

[0134] The vehicle speed upper limit value set in the restriction start state S23 is a value greater than 0. When the vehicle speed upper limit value is set in the restriction start state S23, the main control device 31 controls the force in the direction that hinders the vehicle body 11 from moving so that the vehicle speed of the vehicle body 11 does not exceed the vehicle speed upper limit value. The main control device 31 controls the vehicle speed of the vehicle body 11 so that it does not exceed the vehicle speed upper limit value by setting a limit value to the target speed of the engine 61. The lowest value of the limit value is the idle speed. If the target speed corresponding to the accelerator opening is less than the limit value, the main control device 31 sends a speed command including the target speed corresponding to the accelerator opening to the travel control device 83. When the target speed corresponding to the accelerator opening exceeds the limit value, the main control device 31 sends a speed command with the limit value as the target speed to the travel control device 83. The travel control device 83 controls the throttle actuator 62 so that the speed of the engine 61 becomes the limit value. As a result, the forklift 10 is continuously decelerated by engine braking. The engine brake causes a force in a direction that hinders the movement of the vehicle body 11 to act on the forklift 10. The forklift 10 is decelerated until the rotation speed of the engine 61 reaches a vehicle speed corresponding to the limit value. In the limit start state S23, the alarm device 58 issues an alarm.

[0135] like Fig.10 As shown, when the main control device 31 is in the restriction start state S23, if the restriction start release condition is satisfied, the main control device 31 changes to the restriction release state S21. The restriction start release condition is satisfied when the following condition J1 is satisfied. In addition, when the main control device 31 is in the restriction release state S21, if the first restriction start condition is satisfied, the main control device 31 changes to the restriction start state S23.

[0136] Condition J1: The vehicle is stopped from traveling in the reverse direction and no reverse operation is performed.

[0137] When the main control device 31 is in the restriction start state S23, if the restriction pre-release condition is satisfied, the main control device 31 transitions to the restriction pre-release state S24. The restriction pre-release condition being satisfied means that the following condition K1 is satisfied.

[0138] Condition K1: No one is in the speed limit area in the automatic deceleration area AA2.

[0139] like Fig. 9 As shown, the restriction pre-release state S24 means that the vehicle speed limit is released but the acceleration upper limit value is set to AS2 [m / s 2 ] and the acceleration is limited. AS2 is a value greater than 0 and is a value lower than the maximum acceleration that the forklift 10 can reach. The main control device 31 allows the acceleration of the forklift 10 below AS2. AS2 can be the same as AS1 or a different value from AS1.

[0140] like Fig.10 As shown, when the main control device 31 is in the restriction pre-release state S24, if the second restriction start condition is satisfied, the main control device 31 transitions to the restriction start state S23. The satisfaction of the second restriction start condition means that the following condition L1 is satisfied.

[0141] Condition L1: There is a person in the speed limit area in the automatic deceleration area AA2.

[0142] When the main control device 31 is in the restriction pre-release state S24, if the restriction formal release condition is satisfied, the main control device 31 transitions to the restriction release state S21. The restriction formal release condition being satisfied means that at least one of the following conditions M1 and M2 is satisfied.

[0143] Condition M1: The vehicle speed of the forklift 10 reaches a value obtained by subtracting a second predetermined value from a target vehicle speed.

[0144] Condition M2 ... No back-off operation has been performed.

[0145] Condition M1 can be said to be that the difference between the target vehicle speed and the vehicle speed of the forklift 10, i.e., the speed deviation, is less than the second prescribed value. In the restriction pre-release state S24, since the acceleration restriction is applied, the speed follow-up performance of the forklift 10 is reduced, and the vehicle speed of the forklift 10 is not easy to reach the target vehicle speed. The second prescribed value is set to determine whether the vehicle speed of the forklift 10 has reached the target vehicle speed intended by the operator in a state where the acceleration restriction is applied. As the second prescribed value, for example, any value can be set from 0.5 [km / h] to 2.0 [km / h]. The second prescribed value can be the same as the first prescribed value, or a value different from the first prescribed value.

[0146] In addition, similarly to the case of the travel stop control, the main control device 31 may maintain the trajectory derivation threshold value YT when a person existing in the speed limit area is detected.

[0147] Next, the vehicle speed limit control when the object is an obstacle will be described. The differences from the vehicle speed limit control when the object is a person will be described below, and the similarities with the vehicle speed limit control when the object is a person will be omitted.

[0148] The pre-restriction start condition being satisfied when the object is an obstacle means that both of the following conditions N1 and N2 are satisfied.

[0149] Condition N1: There is an obstacle in the advance warning area in the automatic deceleration area AA2.

[0150] Condition N2: The forklift 10 is traveling in the reverse direction.

[0151] The advance warning area is an area that is farther from the speed limit area. The advance warning area is derived from the speed of the forklift 10 and the speed limit value set according to the position of the obstacle, and is derived in such a way that the time from the obstacle entering the advance warning area to the obstacle entering the speed limit area becomes a predetermined set time. The predetermined set time is, for example, 1 second to 3 seconds. In the case where the object is an obstacle, the advance warning area is, for example, any one of an area farther from the speed limit area within the estimated trajectory T, an area outside the estimated trajectory T and on the extension line of the estimated trajectory T, and an area including both of them.

[0152] The speed limit area when the object is an obstacle is an area within the expected trajectory T in the automatic deceleration area AA2. When the object is an obstacle, the speed limit area is set within the expected trajectory T, which is different from the case where the object is a person. That is, when the obstacle exists within the expected trajectory T, the main control device 31 controls the force in the direction that hinders the movement of the vehicle body 11 so that the speed of the vehicle body 11 does not exceed the upper limit of the vehicle speed. As in the case where the object is a person, the main control device 31 uses engine braking to prevent the speed of the vehicle body 11 from exceeding the upper limit of the vehicle speed.

[0153] The conditions of the preliminary restriction start release condition, the first restriction start condition, the restriction start release condition, the restriction preliminary release condition, the second restriction start condition and the restriction final release condition when the object is an obstacle are conditions after a person is changed into an obstacle.

[0154] In addition, when the object is an obstacle, the shorter the distance from the forklift 10 to the obstacle, the lower the upper limit of the vehicle speed applied to the forklift 10 is set. In the storage unit 33 of the main control device 31 or a storage medium such as an external storage device, a mapping that corresponds the upper limit of the vehicle speed to the distance from the forklift 10 to the obstacle is stored. The main control device 31 sets the upper limit of the vehicle speed based on the mapping. In the case where the object is an obstacle, the upper limit of the vehicle speed applied to the forklift 10 is a value greater than 0. In addition, the upper limit of the vehicle speed is not limited to a method in which the upper limit of the vehicle speed decreases in proportion to the shortening of the distance from the forklift 10 to the obstacle, as long as there is the following correlation: if the distance from the forklift 10 to the obstacle becomes shorter, the upper limit of the vehicle speed becomes lower.

[0155] As described above, the main control device 31 sets the vehicle speed upper limit value according to the state. In the present embodiment, it can be said that the main control device 31 functions as a vehicle speed upper limit setting unit.

[0156] The operation of this embodiment will be described.

[0157] When a person enters the warning area during the travel of the forklift 10, the main control device 31 changes to the pre-travel restriction state S11. The main control device 31 makes the operator aware that the person may enter the expected trajectory T by issuing an alarm through the alarm device 58. When the operator turns the forklift 10 away from the person or stops the forklift 10 without performing a reverse operation, the main control device 31 changes to the normal control state S10. When a person enters the expected trajectory T while the main control device 31 is in the pre-travel restriction state S11, the main control device 31 changes to the travel restriction state S12. The main control device 31 sets the vehicle speed upper limit to 0, and the forklift 10 stops. At this time, the main control device 31 cuts off the transmission of the driving force of the engine 61 to the drive wheels 12 and 13. As a result, the forklift 10 stops due to the deceleration caused by the travel resistance.

[0158] After the main control device 31 changes to the travel restriction state S12, the forklift 10 stops, and if the operator does not perform a reverse operation, the main control device 31 changes to the normal control state S10. When the main control device 31 is in the normal control state S10, if the travel restriction condition is satisfied, the main control device 31 changes to the travel restriction state S12 without passing through the pre-travel restriction state S11. As a situation where the pre-travel restriction condition is not satisfied but the travel restriction condition is satisfied, for example, a situation where the speed of the forklift 10 is high or a situation where an object enters the estimated trajectory T from a blind spot in the detectable range of the object detection unit 51 can be considered.

[0159] When the main control device 31 is in the travel restriction state S12, if there is no more person in the estimated trajectory T before the forklift 10 stops, the main control device 31 changes to the travel restriction pre-release state S13. In addition, if a person enters the estimated trajectory T again after changing to the travel restriction pre-release state S13, the main control device 31 changes to the travel restriction state S12. In the travel restriction pre-release state S13, acceleration is restricted. In the travel restriction state S12, since the speed limit is applied, the speed deviation may become large. Therefore, by making the travel restriction pre-release state S13 between the two states before changing from the travel restriction state S12 to the normal control state S10, the forklift 10 is slowly accelerated.

[0160] When the forklift 10 is accelerated while maintaining the travel restriction pre-release state S13 and the speed deviation becomes smaller, the main control device 31 changes to the normal control state S10. In the travel restriction pre-release state S13, since the acceleration is restricted, it is not possible to accelerate efficiently. When it is desired to accelerate efficiently, the travel restriction pre-release state S13 can be released by disconnecting the accelerator, thereby improving the workability.

[0161] As described above, when the forklift 10 is in a state of moving backward and the person enters the estimated trajectory T, the travel stop control functions and the forklift 10 stops. The forklift 10 is moving backward and the person is located behind the forklift 10. Therefore, it can be said that the vehicle speed upper limit value is set when the forklift 10 is moving in a direction approaching the person.

[0162] When an obstacle enters the pre-warning area during the travel of the forklift 10, the main control device 31 changes to the pre-restriction start state S22. The main control device 31 makes the operator aware that an obstacle is nearby by issuing an alarm through the alarm device 58. When the operator turns the forklift 10 away from the obstacle or stops the forklift 10 without performing a reverse operation, the main control device 31 changes to the restriction release state S21. When an obstacle enters the vehicle speed limit area while the main control device 31 is in the pre-restriction start state S22, the main control device 31 changes to the restriction start state S23. The main control device 31 sets the vehicle speed upper limit value to a value corresponding to the map. At this time, the forklift 10 decelerates by engine braking.

[0163] In the restriction start state S23, although the vehicle speed upper limit is set, the forklift 10 is allowed to travel at a speed below the vehicle speed upper limit. The operator can drive the forklift 10 while avoiding obstacles. When the main control device 31 is in the restriction start state S23, if the restriction start release condition is satisfied, the main control device 31 releases the vehicle speed limit by transitioning to the restriction release state S21.

[0164] When the operator continues the travel of the forklift 10 while maintaining the restriction start state S23 and there is no obstacle in the speed limit area, the main control device 31 changes to the restriction pre-release state S24. As a result, the speed limit is released. In the restriction pre-release state S24, the acceleration is restricted. In the restriction start state S23, since the speed limit is applied, the speed deviation may become large. Therefore, by making the restriction pre-release state S24 between the two states before changing from the restriction start state S23 to the restriction release state S21, the forklift 10 is slowly accelerated.

[0165] When the forklift 10 accelerates while maintaining the restriction pre-release state S24 and the speed deviation becomes smaller, the main control device 31 changes to the restriction release state S21. In the restriction pre-release state S24, since there is a restriction on acceleration, it is not possible to accelerate efficiently. In the case of desiring to accelerate efficiently, the restriction pre-release state S24 can be released by disconnecting the accelerator, thereby improving the workability. In the restriction pre-release state S24, when the operator changes the direction of travel to the forward direction, the main control device 31 changes to the restriction release state S21. In addition, when an obstacle enters the speed limit area again before changing from the restriction pre-release state S24 to the restriction release state S21, the main control device 31 changes to the restriction start state S23.

[0166] As described above, when the forklift 10 is in the reverse state, when the obstacle enters the speed limit area set in the expected trajectory T, the speed limit control for the obstacle functions, and the speed limit is implemented. On the other hand, when the obstacle is outside the expected trajectory T, the speed limit is not implemented. The forklift 10 is in the reverse state, and the obstacle is located behind the forklift 10. Therefore, it can be said that the speed limit value is set when the travel direction of the forklift 10 is the direction approaching the obstacle.

[0167] In this embodiment, the state transitions of the travel stop control, the speed limit control for people, and the speed limit control for obstacles are performed in parallel. Therefore, it is possible to set different speed upper limits and alarm methods in each state transition. In this case, it is sufficient to perform control corresponding to any one of the states by presetting the priority. For example, the main control device 31 performs control determined in the state where the speed upper limit is the lowest.

[0168] The effects of this embodiment will be described.

[0169] (1) The main control device 31 applies a vehicle speed limit when the object is within the predicted trajectory T and the vehicle body 11 is moving in a direction approaching the object. The predicted trajectory T is a trajectory that the forklift 10 is expected to pass through, and therefore, by applying a vehicle speed limit when the object is within the predicted trajectory T, it is possible to appropriately suppress the forklift 10 from contacting the object.

[0170] The main control device 31 controls the engine 61 so as not to exceed the upper limit of the vehicle speed. When the vehicle speed of the vehicle body 11 exceeds the upper limit of the vehicle speed, control is performed to apply a force in a direction that hinders the movement of the vehicle body 11, and control is performed to cut off the driving force to the drive wheels 12 and 13. The deceleration caused by the engine brake can slow down the forklift 10 because the deceleration is low. When the driving force to the drive wheels 12 and 13 is cut off, deceleration caused by the running resistance is performed. The deceleration caused by the running resistance can slow down the forklift 10 because the deceleration is low. Therefore, it is possible to suppress the occurrence of cargo scattering and to impose a speed limit on the forklift 10.

[0171] (2) The main control device 31 performs two types of control: control to cause a force to act in a direction that hinders the movement of the vehicle body 11, and control to cut off the driving force to the drive wheels 12 and 13. In the embodiment, in the travel restriction state S12, the driving force to the drive wheels 12 and 13 is cut off. In the restriction start state S23, the force to act in a direction that hinders the movement of the vehicle body 11 is caused to act by engine braking. In the travel restriction state S12, since the forklift 10 is to be stopped, the driving force to the drive wheels 12 and 13 is cut off. In the restriction start state S23, since it is not necessary to stop the forklift 10, the forklift 10 is decelerated by engine braking. That is, the forklift 10 can be decelerated according to the situation.

[0172] (3) The higher the speed of the vehicle body 11, the longer the main control device 31 extends the estimated trajectory T in the traveling direction. The higher the speed of the vehicle body 11, the shorter the time until reaching the object. Therefore, by extending the estimated trajectory T as the speed of the vehicle body 11 increases, an appropriate speed limit corresponding to the speed of the vehicle body 11 can be performed.

[0173] The embodiment can be implemented by being modified as follows. The embodiment and the following modified examples can be implemented in combination with each other within the scope of no technical contradiction.

[0174] ○ If Fig.11 As shown, the forklift 10 may include a brake mechanism 100 . The brake mechanism 100 includes a brake actuator 101 , a wheel cylinder 102 , and a brake controller 103 .

[0175] Brake actuator 101 is an actuator that controls the supply of hydraulic oil to wheel-brake cylinder 102. Brake actuator 101 controls the supply of hydraulic oil by, for example, a solenoid valve.

[0176] The wheel cylinder 102 is provided on the driving wheels 12 and 13. The wheel cylinder 102 may be provided on the steering wheel 14. The wheel cylinder 102 presses the brake pad against the brake disc using the hydraulic fluid supplied from the brake actuator 101 to generate a friction braking force.

[0177] The hardware configuration of the brake controller 103 is, for example, the same as that of the travel control device 83. The brake controller 103 controls the brake actuator 101 based on a command from the main control device 31. It can be said that the main control device 31 can control the brake mechanism 100 by sending a command to the brake controller 103.

[0178] The main control device 31 can prevent the vehicle speed of the vehicle body 11 from exceeding the upper speed limit by decelerating using the brake mechanism 100 in addition to the deceleration caused by the travel resistance. For example, when the forklift 10 is decelerated in the travel restriction state S12, the main control device 31 sends a cut-off command to the travel control device 83 to cut off the driving force to the drive wheels 12 and 13. The main control device 31 sends a braking command to the brake controller 103. When receiving the braking command, the brake controller 103 controls the brake actuator 101 to supply hydraulic oil to the brake wheel cylinder 102. The brake controller 103 controls so that the deceleration of the forklift 10 becomes a predetermined deceleration limit value [m / s 2 ] or less. The deceleration limit value is a value greater than 0 and is a value lower than the maximum deceleration of the forklift 10. Thus, it is possible to suppress the scattering of cargo during deceleration. The forklift 10 stops by continuously decelerating at a deceleration rate less than the deceleration limit value.

[0179] The main control device 31 can make the vehicle speed of the vehicle body 11 not exceed the upper speed limit value by decelerating by the brake mechanism 100 in addition to the deceleration by the engine brake. For example, in the speed limit control for the obstacle, when the forklift 10 is decelerated in the limit start state S23, the main control device 31 activates the engine brake by sending a speed command to the travel control device 83. The main control device 31 sends the brake command to the brake controller 103. The brake controller 103 controls so that the deceleration of the forklift 10 becomes the predetermined deceleration limit value [m / s 2 ]the following.

[0180] By providing the brake mechanism 100, it is possible to adjust the deceleration of the forklift 10. In addition, by providing the brake mechanism 100, even when the forklift 10 is traveling on a sloped road, it is possible to stop the forklift 10.

[0181] In the case where the forklift 10 is provided with a brake mechanism 100, the deceleration rate when the forklift 10 is decelerated may be set to a lower value as the weight of the cargo is heavier. In this case, the forklift 10 will decelerate more slowly as the weight of the cargo is heavier. Similarly, in the case where the forklift 10 is provided with a brake mechanism 100, the deceleration rate when the forklift 10 is decelerated may be set to a lower value as the lifting height of the cargo handling device 20 is higher. In this case, the forklift 10 will decelerate more slowly as the lifting height of the cargo handling device 20 is higher. In the case where the forklift 10 is provided with a brake mechanism 100, the deceleration rate when the forklift 10 is decelerated may be set to a lower value as the lifting height of the cargo handling device 20 is higher, and the deceleration rate when the forklift 10 is decelerated may be set to a lower value as the weight of the cargo is heavier.

[0182] ○ Alternatively, the main control device 31 may control the vehicle speed of the vehicle body 11 to not exceed the upper limit of the vehicle speed only by deceleration due to engine braking. For example, when the forklift 10 is decelerated in the travel restriction state S12, the main control device 31 sets a limit value for the rotation speed of the engine 61. Then, the main control device 31 sends a rotation speed instruction to the travel control device 83 so that the rotation speed of the engine 61 does not exceed the limit value. The forklift 10 is decelerated by engine braking. In this case, the vehicle speed of the vehicle body 11 will not be less than the vehicle speed corresponding to the idle speed of the engine 61, so the forklift 10 cannot be stopped.

[0183] In addition, the main control device 31 may combine the deceleration by engine braking with the deceleration by the above-mentioned brake mechanism 100. That is, in both the driving restriction state S12 and the obstacle restriction start state S23, the deceleration by engine braking and the deceleration by the brake mechanism 100 may be performed. In this case, it can be said that the main control device 31 does not perform control to cut off the driving force to the drive wheels 12 and 13.

[0184] ○ Alternatively, the main control device 31 may prevent the vehicle speed of the vehicle body 11 from exceeding the upper speed limit value only by deceleration due to the travel resistance. For example, in the restriction start state S23 for the obstacle, the main control device 31 sends a cut-off command to the travel control device 83. The forklift 10 is decelerated by the travel resistance. In this case, the upper speed limit value set in the restriction start state S23 becomes 0.

[0185] In addition, the main control device 31 may combine the deceleration caused by the running resistance and the deceleration by the above-mentioned brake mechanism 100. That is, in the two states of the running restriction state S12 and the obstacle restriction start state S23, the deceleration caused by the running resistance and the deceleration caused by the brake mechanism 100 may be performed. In this case, it can also be said that the main control device 31 does not control the target speed of the engine 61 to set the limit value.

[0186] ○ When the main control device 31 decelerates in the travel restriction state S12, the forklift 10 may be decelerated by two types of deceleration, namely, deceleration by engine braking and deceleration by travel resistance. When the state is changed to the travel restriction state S12, the main control device 31 decelerates by engine braking by sending a speed command to the travel control device 83. The target speed included in the speed command is, for example, the idle speed. The forklift 10 continues to decelerate by engine braking. When the vehicle speed of the vehicle body 11 is less than a threshold value, the main control device 31 sends a cut-off command to the travel control device 83. As the threshold value, for example, a vehicle speed corresponding to the idle speed can be cited. The travel control device 83 cuts off the driving force to the drive wheels 12 and 13. The forklift 10 is further decelerated by the travel resistance. When the forklift 10 travels on a flat road, the forklift 10 stops. By combining the deceleration by engine braking and the deceleration by travel resistance in this way, the forklift 10 can be decelerated at a deceleration higher than the travel resistance and can also be stopped. The above-described control method can be said to be one of two control methods: control to cause a force to act in a direction that hinders the movement of the vehicle body 11 , and control to cut off the driving force to the drive wheels 12 , 13 .

[0187] ○ Alternatively, the main control device 31 may send a torque command to the travel control device 83 instead of a rotation speed command. The torque command includes a target torque. The main control device 31 increases the target torque as the accelerator opening increases. The travel control device 83 controls the throttle actuator 62 so that the torque of the engine 61 follows the target torque. When a speed limit is imposed on the forklift 10, the main control device 31 sets a limit value for the target torque.

[0188] An engine using liquefied petroleum gas as fuel may be used as the engine 61. In this case, the driving force to the drive wheels 12 and 13 can be adjusted by adjusting the throttle opening by the throttle actuator 62.

[0189] The engine 61 may be a diesel engine. In this case, the driving force to the drive wheels 12 and 13 can be adjusted by adjusting the fuel injection amount by the travel control device 83 .

[0190] The forklift 10 may be a vehicle including an HST (Hydro-Static Transmission) instead of the torque converter 71 and the transmission 72 .

[0191] The vehicle speed upper limit value set in the restriction start state S23 may be set to a lower value as the lift height of the cargo handling device 20 is higher.

[0192] The vehicle speed upper limit value set in the restriction start state S23 may be set to a lower value as the weight of the cargo increases.

[0193] ○ Alternatively, the vehicle speed upper limit value set in the restriction start state S23 may be set to a lower value as the lifting height of the cargo handling device 20 is higher, and the vehicle speed upper limit value set in the restriction start state S23 may be set to a lower value as the weight of the cargo is heavier. That is, the above two modified examples described for the vehicle speed upper limit value may be combined.

[0194] The acceleration upper limit value set in the restriction pre-release state S24 may be set to a lower value as the lifting height of the cargo handling device 20 increases. In this case, the forklift 10 accelerates more slowly as the lifting height of the cargo handling device 20 increases.

[0195] The acceleration upper limit value set in the restriction pre-release state S24 may be set to a lower value as the weight of the cargo increases. In this case, the forklift 10 accelerates more slowly as the weight of the cargo increases.

[0196] ○ Alternatively, the acceleration upper limit value set in the restriction pre-release state S24 may be set to a lower value as the lifting height of the cargo handling device 20 is higher, and the acceleration upper limit value set in the restriction pre-release state S24 may be set to a lower value as the weight of the cargo is heavier. That is, the above two modified examples described for the acceleration upper limit value may be combined.

[0197] When neither the vehicle speed upper limit value nor the acceleration upper limit value is changed according to the lift height of the cargo handling device 20 , the forklift 10 may not include the lift height sensor 37 .

[0198] When neither the vehicle speed upper limit value nor the acceleration upper limit value is changed according to the weight of the cargo, the forklift 10 may not include the weight sensor 38 .

[0199] The vehicle speed upper limit value set in the restriction start state S23 may not be changed according to the distance to the object. In other words, the vehicle speed upper limit value set in the restriction start state S23 may be a fixed value.

[0200] The main control device 31 may not extend the length of the estimated trajectory T with respect to the traveling direction as the vehicle speed of the vehicle body 11 increases. In this case, the length of the estimated trajectory T with respect to the traveling direction is set to a predetermined fixed length.

[0201] The main control device 31 may not change the estimated trajectory T according to the steering angle of the steering wheel 14. That is, the estimated trajectory T may be the estimated trajectory T when the forklift 10 is traveling straight in the backward direction, regardless of whether the forklift 10 is turning or not.

[0202] ○ In addition to setting the area between the trajectory LT through which the left end LE of the vehicle body 11 passes and the trajectory RT through which the right end RE of the vehicle body 11 passes as the estimated trajectory T, the main control device 31 may also set an area located outside the area and extending along the trajectory LT and the trajectory RT as the estimated trajectory T. That is, the estimated trajectory T may be a trajectory obtained by adding a margin for expansion in the vehicle width direction of the forklift 10 to the area through which the forklift 10 is expected to pass.

[0203] The main control device 31 may derive the estimated trajectory T from a map in which the vehicle speed and steering angle of the vehicle body 11 are associated with the X-coordinate and the Y-coordinate.

[0204] ○ The main control device 31 may not perform different controls depending on whether the object is a person or an obstacle. Specifically, when the main control device 31 performs automatic deceleration control, if there is an object in the expected trajectory T, the forklift 10 stops traveling, and when there is no object in the expected trajectory T, no speed limit is performed. In addition, when the main control device 31 performs automatic deceleration control, if there is an object in the expected trajectory T, the upper limit of the vehicle speed may be reduced compared to the case where there is an object outside the expected trajectory T. In this case, the obstacle detection device 55 may not determine whether the object is a person.

[0205] ○ The driving stop control can be set to at least two states, the normal control state S10 and the driving restriction state S12. In this case, when the driving restriction condition is satisfied, the main control device 31 changes to the driving restriction state S12, and when the driving restriction release condition is satisfied, the main control device 31 changes to the normal control state S10. That is, the main control device 31 can be set to 0 as long as there is a person in the estimated trajectory T.

[0206] ○ The vehicle speed limit control only needs to set the state of the main control device 31 to at least two states, namely, the restriction release state S21 and the restriction start state S23. In this case, when the first restriction start condition is satisfied, the main control device 31 changes to the restriction start state S23, and when the restriction start release condition is satisfied, the main control device 31 changes to the restriction release state S21. That is, the main control device 31 only needs to be able to set the vehicle speed upper limit value when an object exists in the vehicle speed limit area.

[0207] The main control device 31 only needs to be able to set at least the vehicle speed upper limit value, and does not need to set the acceleration upper limit value.

[0208] The automatic deceleration area AA2 may be an area narrower than the detectable range of the object by the object detection unit 51 .

[0209] ○Alarms in the pre-travel restriction state S11 and the pre-restriction start state S22 may also be issued when the forklift 10 turns around.

[0210] In the restricted driving state S12, the warning device 58 may not issue a warning.

[0211] ○ In all states of the travel stop control, the speed limit control for people, and the speed limit control for obstacles, the alarm device 58 may not be used to issue an alarm. In this case, the forklift 10 may not include the alarm device 58.

[0212] The object detection unit 51 may be an object detection unit that detects the position of an object existing in the forward direction of the traveling direction of the vehicle body 11. In this case, the stereo camera 52 is arranged toward the front of the forklift 10. When the position of the object existing in the forward direction of the forklift 10 is detected by the object detection unit 51, the automatic deceleration area AA2 becomes an area extending forward from the forklift 10. In addition, when the forklift 10 is in the forward direction, the travel stop control, the speed limit control for people, and the speed limit control for obstacles function. In detail, in each of the travel stop control, the speed limit control for people, and the speed limit control for obstacles, the "rear" and "front" described in the embodiment are reversed, so that when the forklift 10 is in the forward direction, the speed limit can be applied according to the position of the object. When the position of the object existing in the forward direction of the traveling direction of the vehicle body 11 is detected by the object detection unit 51, the main control device 31 derives the estimated trajectory T extending in the forward direction.

[0213] The object detection unit 51 may be an object detection unit that can detect the position of an object existing in either the backward direction or the forward direction of the vehicle body 11. In this case, one object detection unit 51 may be used to detect objects existing in either the backward direction or the forward direction of the vehicle body 11, or an object detection unit 51 for the forward direction and an object detection unit 51 for the backward direction may be provided. When the position of an object existing in either the backward direction or the forward direction of the vehicle body 11 is detected, when the forklift 10 is moving forward, the vehicle speed is limited due to the object existing in the forward direction. When the forklift 10 is moving backward, the vehicle speed is limited due to the object existing in the backward direction. That is, it can be said that the main control device 31 sets the vehicle speed upper limit value when the moving direction of the vehicle body 11 is close to the object detected by the object detection unit 51.

[0214] ○ The object detection unit 51 may also use a ToF (Time of Flight) camera, LIDAR (Laser Imaging Detection and Ranging), millimeter wave radar, etc. instead of the stereo camera 52. The ToF camera includes a camera and a light source for irradiating light, and derives the distance in the depth direction for each pixel of the image captured by the camera based on the time until the reflected light of the light irradiated from the light source is received. LIDAR is a distance meter that can identify the surrounding environment by irradiating laser light while changing the irradiation angle and receiving the reflected light reflected from the part irradiated by the laser. Millimeter wave radar refers to a radar that can identify the surrounding environment by irradiating radio waves of a specified frequency band to the surroundings. The stereo camera 52, ToF camera, LIDAR and millimeter wave radar are sensors that can measure three-dimensional coordinates in the world coordinate system. As the object detection unit 51, it is preferable to have a sensor that can measure three-dimensional coordinates. In the case where the object detection unit 51 includes a sensor that can measure three-dimensional coordinates, the obstacle detection device 55 can determine whether the object is a person or an obstacle by using a person determiner that has been pre-machined. Furthermore, the object detection unit 51 may include a combination of the stereo camera 52 and a plurality of sensors such as LIDAR.

[0215] In addition, the object detection unit 51 may also include a sensor capable of measuring the coordinates of an object in an XY plane, which is a coordinate plane representing a horizontal plane, instead of the stereo camera 52. That is, as a sensor, a sensor capable of measuring the two-dimensional coordinates of an object may also be used. As such a sensor, for example, a two-dimensional LIDAR that irradiates laser light while changing the irradiation angle in the horizontal direction may be used.

[0216] ○ The stereo camera 52 may include three or more cameras.

[0217] ○ A portion other than the object detection unit 51 may include the alarm device 58 .

[0218] ○ The main control device 31 may directly activate the alarm device 58.

[0219] The forklift 10 may be a three-wheeled forklift 10. In this case, the main control device 31 derives the estimated trajectory T based on the formula or map for deriving the estimated trajectory T of the three-wheeled forklift 10. That is, the formula or map for deriving the estimated trajectory T changes depending on the type of the engine-type industrial vehicle.

[0220] The forklift 10 may be a forklift capable of switching between automatic operation and manual operation.

[0221] The forklift 10 may be a forklift that is remotely operated by an operator who is not riding on the forklift 10 .

[0222] ○ The estimated trajectory derivation unit and the vehicle speed upper limit setting unit may be devices different from the main control device 31. In this case, the estimated trajectory derivation unit and the vehicle speed upper limit setting unit are connected to the main control device 31 via the bus 40, so that the main control device 31, the estimated trajectory derivation unit, and the vehicle speed upper limit setting unit can obtain information from each other.

[0223] The main control device 31 only needs to perform at least one of the travel stop control and the vehicle speed limit control for the obstacle.

[0224] ○The main control device 31 and the travel control device 83 may be the same control device.

[0225] The main control device 31, the travel control device 83, and the object detection unit 51 may be configured to acquire information from each other via a wireless device.

[0226] ○ The engine-type industrial vehicle may be any vehicle as long as it is a tractor for transporting goods, a picker for picking goods, etc., and is used to perform operations in a limited area. That is, the engine-type industrial vehicle may be a vehicle that does not have a cargo handling device 20 for unloading or loading goods.

Claims

1. An engine-type industrial vehicle, characterized in that: have: engine; an acceleration sensor, which detects the accelerator opening; A power transmission mechanism that transmits the driving force of the engine to the driving wheels; a main control device for adjusting the driving force transmitted to the driving wheel; an object detection unit that detects a position of an object existing in a traveling direction of the vehicle body; an estimated trajectory deriving unit that derives an estimated trajectory as a trajectory that the vehicle body is expected to pass; and a vehicle speed upper limit setting unit for limiting the vehicle speed by setting a vehicle speed upper limit value when the object detected by the object detection unit is located within the predicted trajectory and the vehicle is moving in a direction approaching the object, An automatic deceleration area is set within the detectable range of the object by the object detection unit. The vehicle speed upper limit setting unit sets the vehicle speed upper limit value lower when a person is present in the automatic deceleration area and within the predicted trajectory than when the person is present in the automatic deceleration area and outside the predicted trajectory. The main control device is configured to prevent the vehicle speed of the vehicle body from exceeding the vehicle speed upper limit by performing at least one of control of causing a force to act in a direction that hinders the movement of the vehicle body and control of cutting off the driving force to the drive wheels.

2. The engine-driven industrial vehicle according to claim 1, wherein: The automatic deceleration area includes a speed limit area where the speed limit is applied in an area outside the predicted trajectory. The vehicle speed upper limit setting unit implements the vehicle speed limit by setting the vehicle speed upper limit value greater than 0 when a person is present in the vehicle speed limit area. The above main control device When a person is no longer present in the speed limit area while the speed limit is being enforced, acceleration restriction is enforced. When accelerator-off is detected in a state where the acceleration limitation is applied, the acceleration limitation is released.

3. The engine-type industrial vehicle according to claim 1, wherein: The vehicle speed upper limit setting unit sets the vehicle speed upper limit value to 0 when a person is present within the predicted trajectory. The above main control device When the person is no longer within the predicted trajectory while the vehicle speed limit is set to 0, acceleration restriction is applied. When accelerator-off is detected in a state where the acceleration limitation is applied, the acceleration limitation is released.

4. The engine-driven industrial vehicle according to claim 3, wherein: When at least one of the following conditions is met: the vehicle speed reaches a value obtained by subtracting a specified value from a target vehicle speed, and the vehicle body is not operated in a manner such that the direction of travel becomes a direction approaching the object, the main control device releases the acceleration limitation.

5. The engine-type industrial vehicle according to claim 1, wherein: The main control device stops the travel of the vehicle body by setting the vehicle speed upper limit value to 0 when the object is present within the predicted trajectory, and does not impose the vehicle speed limit when the object is not present within the predicted trajectory.

6. The engine-type industrial vehicle according to any one of claims 1 to 5, wherein: It is equipped with a brake mechanism operated by the above-mentioned main control device, The main control device is configured to operate the brake mechanism so that the vehicle speed of the vehicle body does not exceed the vehicle speed upper limit.

7. The engine-type industrial vehicle according to any one of claims 1 to 6, wherein: The main control device is configured to perform two types of control: a control for causing a force to act in a direction that hinders the travel of the vehicle body; and a control for cutting off the driving force to the driving wheels.

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