Industrial vehicle

Abstract

A fork truck (10) is provided with a main control device (31), a travel motor (41), a travel control device (43), and an object detection section (51). The travel control device (43) controls the travel motor (41). The object detection section (51) detects the position of an object present in the backward direction of the fork truck (10). The main control device (31) sets a limit value by start limit control. In the start limit control, the limit value is set so that travel is permitted in a case where it is determined that the operator has recognized the presence of the object. The main control device (31) sets a limit value by automatic deceleration control. If the limit value set by the start limit control is a limit value permitting travel, the main control device (31) performs speed limitation in accordance with the limit value.

Description

Technical Field

[0001] The present disclosure relates to industrial vehicles. Background Art

[0002] Industrial vehicles used in workplaces such as factories, commercial facilities, and ports are sometimes equipped with a speed limit function that limits the vehicle's speed based on the location of objects around the industrial vehicle. For example, Patent Document 1 discloses an industrial vehicle equipped with an object detection unit that detects objects around the industrial vehicle and a control device that controls the speed of the industrial vehicle. The control device decelerates the industrial vehicle if an object is present in a deceleration control area. The control device stops the industrial vehicle if an object is present in a stop control area.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2015-170284 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] As disclosed in Patent Document 1, in order to implement speed limits appropriate to the situation in an industrial vehicle, multiple speed limit functions may be implemented simultaneously. In this case, the control device may implement multiple speed limit functions by executing multiple controls in parallel. When multiple controls are implemented in parallel, the operability of the industrial vehicle may be reduced due to the speed limit being implemented separately in each control. For example, one of the multiple speed limit functions may be designated as the first control, and a control different from the first control may be designated as the second control. Suppose that the speed limit is implemented using the first control while the industrial vehicle is traveling to avoid an object surrounding it. In this case, the speed limit may also be implemented using the second control due to the presence of the object surrounding the industrial vehicle. If the speed limit permitted by the second control is lower than the speed limit permitted by the first control, the second control may hinder the movement to avoid the object.

[0008] An object of the present disclosure is to provide an industrial vehicle capable of suppressing a decrease in workability.

[0009] Solutions for solving problems

[0010] An industrial vehicle that solves the above problems includes a drive device and a travel control device that controls the drive device, the industrial vehicle including an object detection section that detects a position of an object present in a vicinity of the industrial vehicle, a first control section that sets a limit value for performing a speed limit including at least any one of a speed limit and an acceleration limit of the industrial vehicle when a vehicle speed of the industrial vehicle is in a first vehicle speed range, a second control section that sets the limit value when the vehicle speed of the industrial vehicle is in a second vehicle speed range, and a speed limit section that performs the speed limit in accordance with the limit value selected from the limit value set by the first control section and the limit value set by the second control section, a lower limit value of the second vehicle speed range being a value higher than a lower limit value of the first vehicle speed range, the first control section including a start prohibition control section that sets the limit value so that travel of the industrial vehicle is prohibited when the object is detected by the object detection section, and a start permission control section that sets the limit value so that the travel of the industrial vehicle is permitted when it is determined that an operator of the industrial vehicle recognizes presence of the object, the speed limit section performing the speed limit in accordance with the limit value set by the first control section when the limit value is set by the start permission control section.

[0011] The limit value set by the start permission control section is a limit value that permits the travel of the industrial vehicle. Therefore, the industrial vehicle can travel when the limit value is set by the start permission control section. The limit value is set by the start permission control section when it is determined that the operator of the industrial vehicle recognizes presence of the object. Therefore, the avoidance action for avoiding the object is sometimes being performed when the limit value is set by the start permission control section. At this time, if the limit value is set by the second control section and the speed limit is performed in accordance with the limit value, it becomes a cause of hindering the avoidance action. The avoidance action is hindered by the second control section is suppressed by being set to perform the speed limit in accordance with the limit value set by the first control section when the limit value is set by the start permission control section. Therefore, reduction in workability can be suppressed.

[0012] The above industrial vehicle can also include an alarm device and a predicted trajectory derivation section that derives a predicted trajectory that is a trajectory through which the industrial vehicle is predicted to pass, the start permission control section including a first permission control section that performs the setting of the limit value and performs an alarm by the alarm device, and a second permission control section that performs the setting of the limit value and does not perform an alarm by the alarm device, the speed limit section performing the speed limit in accordance with the limit value set by the first control section when the limit value is set by the second permission control section and the object is not present in the predicted trajectory derivation section.

[0013] In the industrial vehicle, the speed limiting unit may limit the speed according to the limit value set by the first control unit in either case where the limit value is set by the start prohibition control unit or the limit value is set by the start permission control unit.

[0014] Effects of the Invention

[0015] According to the present invention, it is possible to suppress a decrease in workability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a three-dimensional diagram of a forklift.

[0017] Figure 2 This is a schematic diagram of a forklift.

[0018] Figure 3 : is a flowchart showing the processing performed by the obstacle detection device.

[0019] Figure 4 Schematic diagram showing the automatic deceleration area and the start restriction area.

[0020] Figure 5 is a diagram schematically showing an estimated trajectory.

[0021] Figure 6 This is a diagram schematically showing a predicted trajectory when the vehicle speed of the forklift is increased.

[0022] Figure 7 Schematically shows a predicted trajectory of a forklift when turning.

[0023] Figure 8 The diagram schematically shows a predicted trajectory when the forklift is turned and its speed is increased.

[0024] Figure 9 This is the state transition diagram of the start restriction control.

[0025] Figure 10 This is a table showing the correspondence between each state to which the main control device transitions and the vehicle speed upper limit value, the acceleration upper limit value, and the deceleration upper limit value.

[0026] Figure 11 This is a table for explaining whether the start restriction conditions are satisfied.

[0027] Figure 12 This is a table for explaining the satisfaction of the start restriction release conditions.

[0028] Figure 13This is the state transition diagram of the driving restriction control.

[0029] Figure 14 It is the state transition diagram of speed limit control.

[0030] Figure 15 This is a flowchart showing the processing performed by the main control device. DETAILED DESCRIPTION

[0031] Hereinafter, one embodiment of an industrial vehicle will be described.

[0032] like Figure 1 As shown, a forklift 10 as an industrial vehicle includes: a vehicle body 11; two drive wheels 12 and 13, which are arranged at the front lower part of the vehicle body 11; two steering wheels 14, which are arranged at the rear lower part of the vehicle body 11; and a cargo handling device 20. The drive wheels 12 and 13 are arranged separately in the vehicle width direction. The two steering wheels 14 are arranged adjacent to each other in the vehicle width direction. The two steering wheels 14 are arranged at a central position between the drive wheels 12 and 13 in the vehicle width direction. When the two adjacently arranged steering wheels 14 are regarded as one steering wheel 14, the forklift 10 can be regarded as a three-wheeled forklift. The vehicle body 11 includes a roof guard 15 provided above the driver's seat. In the following description, front, back, left, and right refer to the front, back, left, and right of the forklift 10.

[0033] The cargo handling device 20 includes a mast 21 erected at the front of the vehicle body 11; a pair of forks 22 arranged to be raised and lowered together with the mast 21; and a lift cylinder 23 for raising and lowering the mast 21. Cargo is loaded onto the forks 22. The lift cylinder 23 is a hydraulic cylinder. When the mast 21 is raised or lowered by extending or retracting the lift cylinder 23, the forks 22 are raised and lowered accordingly. The forklift 10 of this embodiment is a forklift that operates both in travel and cargo loading and unloading operations through operator control.

[0034] like Figure 2 As shown, the forklift 10 includes an accelerator pedal 16, a steering lever 17, a main control device 31, an acceleration sensor 34, a steering sensor 35, a tire angle sensor 36, a lift height sensor 37, a weight sensor 38, a travel motor 41, a rotation speed sensor 42, a travel control device 43, an object detection unit 51 and a bus 60.

[0035] The main control unit 31 includes a processor 32 and a storage unit 33. The processor 32 may be, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), or a DSP (Digital Signal Processor). The storage unit 33 includes RAM (Random Access Memory) and ROM (Read Only Memory). The storage unit 33 stores programs for operating the forklift 10. In other words, the storage unit 33 stores program code or instructions configured to cause the processor 32 to execute processes. The storage unit 33, or computer-readable medium, includes all available media accessible by general-purpose or special-purpose computers. The main control unit 31 may also be configured using hardware circuits such as ASICs (Application Specific Integrated Circuits) and FPGAs (Field Programmable Gate Arrays). The main control unit 31, as a processing circuit, may include one or more processors, one or more hardware circuits such as ASICs or FPGAs, or a combination thereof, that operate according to computer programs.

[0036] The accelerator sensor 34 detects the amount of operation of the accelerator pedal 16, that is, 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 based on the electrical signal from the accelerator sensor 34.

[0037] The direction sensor 35 detects the direction in which the steering lever 17, which indicates the direction of travel, is operated. The direction sensor 35 detects, with the neutral position as a reference, whether the steering lever 17 has been operated in the forward direction or the reverse direction. The direction sensor 35 outputs an electrical signal corresponding to the direction in which the steering lever 17 has been operated to the main control unit 31. The main control unit 31 can identify the direction in which the steering lever 17 has been operated based on the electrical signal from the direction sensor 35. The main control unit 31 can determine whether the operator has instructed forward movement, reverse movement, or neither.

[0038] 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 based on the electrical signal from the tire angle sensor 36.

[0039] The lift height sensor 37 detects the lift height of the cargo handling device 20. The lift height of the cargo handling device 20 is the height from the road surface to the fork 22. The lift height sensor 37 is, for example, a reel sensor. The lift height sensor 37 outputs an electrical signal corresponding to the lift height to the main control device 31. The main control device 31 can identify the lift height of the cargo handling device 20 based on the electrical signal from the lift height sensor 37.

[0040] 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 unit 31. The main control unit 31 can identify the weight of the cargo based on the electrical signal from the weight sensor 38.

[0041] The travel motor 41 is a drive device for traveling the forklift 10. When the travel motor 41 is driven, the drive wheels 12 and 13 rotate, and the forklift 10 travels.

[0042] The rotation speed sensor 42 detects the rotation speed of the travel motor 41 . For example, a rotary encoder can be used as the rotation speed sensor 42 . The rotation speed sensor 42 outputs an electrical signal corresponding to the rotation speed of the travel motor 41 to the travel control device 43 .

[0043] The travel control device 43 is a motor driver that controls the rotational speed of the travel motor 41. The travel control device 43 can identify the rotational speed and rotational direction of the travel motor 41 based on the electrical signal from the rotational speed sensor 42. The rotational direction of the travel motor 41 is indicated by ± signs. A + sign indicates forward rotation, while a - sign indicates reverse rotation.

[0044] The travel motor 41, rotational speed sensor 42, and travel control device 43 are provided separately for each of the two drive wheels 12 and 13. The travel control device 43 independently controls the rotational speed and rotational direction of the travel motor 41 provided for each of the two drive wheels 12 and 13, enabling independent control of the rotational speed and rotational direction of the two drive wheels 12 and 13. The rotational speed of the travel motor 41 provided for each of the two drive wheels 12 and 13 can be detected separately by the rotational speed sensor 42.

[0045] The object detection unit 51 includes: a stereo camera 52; an obstacle detection device 55 that detects an object based on the image captured by the stereo camera 52; and an alarm device 58. Figure 1As shown, the stereo camera 52 is disposed on the roof guard 15. The stereo camera 52 is disposed 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 captures images from behind the forklift 10. Therefore, the objects detected by the obstacle detection device 55 are objects behind the forklift 10. The alarm device 58 and the obstacle detection device 55 may be integrated with the stereo camera 52 and disposed on the roof guard 15 together with the stereo camera 52. Alternatively, the alarm device 58 and the obstacle detection device 55 may be disposed at a location different from the roof guard 15.

[0046] like Figure 2 As shown, the stereo camera 52 includes two cameras 53 and 54. The cameras 53 and 54 use, for example, CCD image sensors or CMOS image sensors. 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 the same object will appear offset in the images captured by the two cameras 53 and 54. Specifically, when the same object is captured, the object appearing in the images captured by the two cameras 53 and 54 will be offset by pixels 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 100° or more is used, but a non-wide-angle stereo camera may also be used as the stereo camera 52.

[0047] The obstacle detection device 55 includes a processor 56 and a storage unit 57. The processor 56 may be, for example, a CPU, GPU, or DSP. The storage unit 57 includes RAM and ROM. The storage unit 57 stores various programs for detecting objects based on images captured by the stereo camera 52. The storage unit 57 can be said to store program code or instructions configured to cause the processor 56 to execute processes. The storage unit 57, i.e., computer-readable media, includes all available media that can be accessed by general-purpose or special-purpose computers. The obstacle detection device 55 may also be composed of hardware circuits such as ASICs and FPGAs. As a processing circuit, the obstacle detection device 55 may include one or more processors, one or more hardware circuits such as ASICs or FPGAs, or a combination thereof, operating according to computer programs.

[0048] The obstacle detection device 55 detects objects around the forklift 10 by repeatedly performing the following process at a predetermined control cycle. Furthermore, 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.

[0049] like Figure 3 As shown, in step S100 , the obstacle detection device 55 obtains images from the cameras 53 and 54 of the stereo camera 52 .

[0050] Next, in step S110, the obstacle detection device 55 performs stereo processing to obtain a parallax image. A parallax image is an image in which parallaxes (px) are associated with pixels. A parallax image is not necessarily an image to be displayed, but rather data indicating that each pixel in the parallax image is associated with a parallax. Parallax can be obtained by comparing images captured by the two cameras 53 and 54 included in the stereo camera 52 and deriving the difference in the number of pixels between the images for the same feature points present 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. For each pixel in the reference image, the obstacle detection device 55 extracts the pixel of the comparison image that is most similar. The obstacle detection device 55 calculates the difference in the number of pixels between the reference image and the comparison image as the parallax. This allows the acquisition of a parallax image in which each pixel in the reference image is associated with a parallax. A feature point is a recognizable boundary, such as an edge of an object. Feature points can be detected based on brightness information, for example.

[0051] 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.

[0052] like Figure 3 As shown, in step S130, the obstacle detection device 55 extracts an object by clustering feature points. The obstacle detection device 55 identifies a collection of feature points representing a portion of an object, each assumed to represent the same object, as a point cluster and extracts this point cluster as an object. Based on the coordinates of the feature points within the world coordinate system derived in step S120, the obstacle detection device 55 clusters feature points within a specified range, treating them as a single point cluster. The obstacle detection device 55 treats the clustered point cluster as a single object. The clustering of feature points in step S130 can be performed using various methods.

[0053] 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 constituting 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 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 coordinate of 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.

[0054] Next, in step S150, the obstacle detection device 55 determines whether the object is a person or an obstacle other than a person. Various methods can be used to determine whether the object is a person. In this embodiment, the obstacle detection device 55 performs person detection on images captured by either 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 then converts these camera coordinates into coordinates of the image captured by the cameras 53 and 54. In this embodiment, the obstacle detection device 55 converts the coordinates of the object in the world coordinate system into coordinates of a reference image. The obstacle detection device 55 performs person detection on the coordinates of the object in the reference image. For example, person detection is performed using feature extraction and a person determinator that has undergone machine learning. Examples of feature extraction methods include extracting features of local regions in an image, such as HOG (Histogram of Oriented Gradients) features and Haar-Like features. As a human determinator, 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 the 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.

[0055] 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 that gives an alarm by sound, a lamp that gives an alarm by light, or a combination thereof.

[0056] The main control unit 31, the travel control unit 43, and the object detection unit 51 are configured to mutually acquire information via a bus 60. The main control unit 31, the travel control unit 43, and the object detection unit 51 mutually acquire information by communicating in accordance with a vehicle communication protocol such as CAN (Controller Area Network) or LIN (Local Interconnect Network).

[0057] The main control unit 31 obtains the rotational speed and direction of the travel motor 41 from the travel control unit 43 and the steering angle from the tire angle sensor 36 to derive the vehicle speed of the forklift 10. The vehicle speed of the forklift 10 can be derived using the rotational speed and direction of each travel motor 41 provided for each drive wheel 12, 13, the gear ratio, the outer diameter of the drive wheels 12, 13, the steering angle detected by the tire angle sensor 36, and other factors. The main control unit 31 also derives the travel direction of the forklift 10 along with the vehicle speed. The travel direction of the forklift 10 refers to either forward or reverse. The travel direction of the forklift 10 is indicated by the ± sign attached to the vehicle speed. A + sign indicates the forward direction, while a - sign indicates the reverse direction. In this embodiment, the vehicle speed is expressed without the ± sign. That is, the vehicle speed in this embodiment is expressed as its absolute value.

[0058] The main control device 31 activates the alarm device 58 by sending an alarm command via the bus 60. 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 upon receiving the alarm command.

[0059] Next, the vehicle speed control performed in the forklift 10 will be described.

[0060] In the forklift 10, the main control unit 31 controls the vehicle speed based on the position and type of objects detected by the object detection unit 51. The type of 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. Vehicle speed control includes automatic deceleration control and start restriction control.

[0061] like Figure 4As shown, within the object detection range of the object detection unit 51, an automatic deceleration area AA2 for automatic deceleration control and a start restriction area AA1 for start restriction control are defined. The object detection range of the object detection unit 51 can also be considered the imageable range of the stereo camera 52. In this embodiment, the automatic deceleration area AA2 is the same as the object detection range of the object detection unit 51. The automatic deceleration area AA2 extends from the location 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 defined by X and Y coordinates in the world coordinate system. The start restriction area AA1 is defined within the automatic deceleration area AA2 and is narrower than the automatic deceleration area AA2. The start restriction area AA1 extends from the location of the stereo camera 52 to the rear of the forklift 10 and in the vehicle width direction of the forklift 10. The start restriction area AA1 is defined by X and Y coordinates in the world coordinate system. The automatic deceleration area AA2 can be considered to include a location farther away from the forklift 10 than the start restriction area AA1.

[0062] In this embodiment, the restricted start area AA1 is divided into three areas: a central area N, a left area NL located to the left of the central area N, and a right area NR located to the right of the central area N. The central area N is an area facing the forklift 10 in the front-to-rear direction. The left-to-right dimension of the central area N matches the width dimension of the forklift 10. The central area N can also be considered an area through which the forklift 10 passes when traveling straight in the reverse direction. The left area NL can be considered an area through which the forklift 10 passes when turning left in the reverse direction. The right area NR can be considered an area through which the forklift 10 passes when turning right in the reverse direction.

[0063] like Figure 5 As shown, the main control device 31 derives the predicted trajectory T of the forklift 10. The predicted trajectory T refers to the trajectory that the forklift 10 is expected to travel. In this embodiment, the main control device 31 derives the predicted trajectory T that the forklift 10 is expected to travel when the forklift 10 is traveling in the reverse direction, for example, when the operator operates the steering lever 17 in the direction indicating reverse travel.

[0064] The estimated trajectory T can be derived based on 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 center axis of the drive 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 can therefore be pre-stored in the storage unit 33 of the main control unit 31, etc. The estimated trajectory T is the 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 unit 31 derives the X and Y coordinates of the estimated trajectory T extending toward the rear of the forklift 10 in the world coordinate system.

[0065] like Figure 5 and Figure 6 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 7 and Figure 8 As shown, when the forklift 10 is turning, the predicted trajectory T curves from the forklift 10 in 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 in the direction of the turn when the forklift 10 is turning.

[0066] Figure 6 The forklift shown is 10 Figure 5 The forklift 10 in the state shown is at a high speed. Figure 8 The forklift shown is 10 Figure 7 The forklift 10 shown is at a high speed. Figures 5 to 8 As shown, the higher the speed of the forklift 10, the more the main control unit 31 extends the estimated trajectory T in the direction of travel. In this embodiment, the trajectory derivation threshold value YT is changed according to the vehicle speed. Trajectory derivation The trajectory derivation threshold value YT is a threshold value set for the Y coordinate in the world coordinate system. As the vehicle speed increases, the threshold value YT becomes farther away from the Y coordinate of the forklift 10. The main control unit 31 derives the estimated trajectory T from the forklift 10 to the trajectory derivation threshold value YT. In addition, the method of extending the estimated trajectory T in the direction of travel as the speed of the forklift 10 increases is not limited to a method in which the speed of the forklift 10 and the length of the estimated trajectory T in the direction of travel are proportional to each other. It is sufficient as long as there is a correlation that the length of the estimated trajectory T in the direction of travel increases as the speed of the forklift 10 increases.

[0067] The estimated trajectory T is derived within the automatic deceleration area AA2. The minimum value of the trajectory derivation threshold value YT can be the Y coordinate of the position farthest from the forklift 10 in the start restricted area AA1. In other words, the trajectory derivation threshold value YT is set so that even when the forklift 10 is stopped and the vehicle speed is 0 [km / h], the estimated trajectory T is derived within the start restricted area AA1. In this embodiment, the main control unit 31 functions as a predicted trajectory derivation unit.

[0068] The start restriction control will be described. Note that the X coordinate and Y coordinate in the following description are X coordinates and Y coordinates in the world coordinate system.

[0069] like Figure 9 As shown, in the start restriction control, by setting the state of the main control device 31 to any of the normal control state S10, the start restriction state S2, the start prohibition state S3, the forced operation state S4 and the forced operation pre-release state S5, control corresponding to each state is performed.

[0070] like Figure 10 As shown, the normal control state S10 indicates a state in which no speed limit is applied. Furthermore, in the normal control state S10, no restrictions are imposed on acceleration or deceleration. When the main control unit 31 is in the normal control state S10, the main control unit 31 calculates a target vehicle speed based on the accelerator position detected by the acceleration sensor 34. Based on the target vehicle speed, the main control unit 31 calculates a target rotational speed. The target rotational speed is the rotational speed required for the forklift 10 to reach the target vehicle speed. The target rotational speed is derived separately for each of the two travel motors 41. Furthermore, the main control unit 31 determines whether to move the forklift 10 forward or backward based on the direction of operation of the steering lever 17. The main control unit 31 generates a command containing information indicating the target rotational speed and information indicating the rotational direction of the travel motors 41, and provides the command to the travel control unit 43. The travel control unit 43 controls the travel motors 41 to follow the target rotational speed based on the command. The travel control unit 43 controls the travel motors 41 to rotate in the rotational direction based on the command. Thus, in the normal control state S10, the forklift 10 travels at a vehicle speed corresponding to the amount of operation of the accelerator pedal 16 by the operator. Furthermore, in a forklift 10 capable of independently controlling the rotational speeds of the two drive wheels 12 and 13, as in this embodiment, the forklift 10 can be turned by adjusting the rotational speeds and rotational directions of the two travel motors 41 in accordance with the operator's turning operation, that is, in accordance with the angle of the steering wheel. Therefore, in the case of a forklift 10 that turns using the difference in the rotational speeds of the two travel motors 41, the main control unit 31 derives a target rotational speed based on the target vehicle speed and the steering wheel angle.

[0071] Furthermore, the state in which speed restriction is not applied includes not only a state in which no upper speed limit is set, but also a state in which a speed upper limit is set that substantially disables the forklift 10, such as a state in which a speed upper limit is set that is higher than the maximum speed that the forklift 10 can reach. Similarly, the state in which acceleration restriction is not applied includes not only a state in which no upper acceleration limit is set, but also a state in which an acceleration upper limit is set that substantially disables the forklift 10, such as a state in which an acceleration upper limit is set that is higher than the maximum speed that the forklift 10 can reach. The deceleration restriction is similar to the acceleration restriction. A state in which at least one of a speed restriction or an acceleration restriction is applied is considered a state in which speed restriction is applied. The speed upper limit and the acceleration upper limit are limit values ​​used to implement speed restriction.

[0072] like Figure 9 As shown, when the main control device 31 is in the normal control state S10, if the start restriction condition is satisfied, the main control device 31 transitions from the normal control state S10 to the start restriction state S2. The start restriction condition being satisfied means that all of the following conditions A1, A2, and A3 are satisfied.

[0073] Condition A1: An object exists in the restricted start area AA1.

[0074] Condition A2: The detection result of the direction sensor 35 is neutral, or the detection result of the direction sensor 35 is backward and the area N, NL, NR where the object exists is consistent with the direction of the expected trajectory T.

[0075] Condition A3: The forklift 10 is stopped.

[0076] The object in condition A1 can be a person or an obstacle other than a person. As previously mentioned, after the obstacle detection device 55 derives the object's position, it determines whether the object is a person or an obstacle. Because determining whether an object is a person takes a long time, the obstacle detection device 55 is sometimes configured to transmit information indicating the object's position to the main control device 31 before transmitting information indicating whether the object is a person. The main control device 31 can determine that condition A1 is satisfied at the stage of identifying the object's position, thereby increasing the speed of determination compared to a method that determines whether condition A1 is satisfied after determining whether the object is a person or an obstacle. Whether condition A1 is satisfied can be determined based on the object's X and Y coordinates. The restricted start area AA1 is defined by X and Y coordinates, so the presence of an object in the restricted start area AA1 can be determined based on the object's X and Y coordinates.

[0077] The state where the object-containing regions N, NL, and NR are aligned with the predicted trajectory T can also be considered a state where the object-containing regions in the central region N, left region NL, and right region NR, which divide the start restricted area AA1, overlap with the predicted trajectory T. In other words, it can be understood as a state where an object exists within the predicted trajectory T. If a single object is located across multiple regions N, NL, and NR, or if multiple objects are located in different regions N, NL, and NR, the main control device 31 determines that an object exists in each region N, NL, and NR. In this case, the main control device 31 determines that condition A2 is satisfied if any of the object-containing regions N, NL, and NR is aligned with the predicted trajectory T.

[0078] Conditions A1 and A2 can be obtained by Figure 11 The table shown is used to represent this. Figure 11 The corresponding relationship between the regions N, NL, and NR where the object exists and the detection results and the estimated trajectory T of the direction sensor 35 when the conditions A1 and A2 are satisfied is shown. Figure 11 The indicated “all” means that the estimated trajectory T can extend in any direction. Figure 11 The illustrated “left turn” indicates that the projected trajectory T extends to the left. Figure 11 The “right turn” shown in FIG. 1 indicates that the trajectory T is expected to extend to the right. Figure 11 As shown, if an object is present in the restricted start area AA1 and the detection result of the direction sensor 35 is neutral, conditions A1 and A2 are satisfied regardless of the direction of the estimated trajectory T. If an object is present in the left area NL, conditions A1 and A2 are satisfied not only when the detection result of the direction sensor 35 is neutral, but also when the detection result of the direction sensor 35 is reverse and the estimated trajectory T (turning direction) is left. If an object is present in the left area NL and the right area NR and no object is present in the center area N, conditions A1 and A2 are satisfied when the detection result of the direction sensor 35 is reverse and the estimated trajectory T extends to the right or left. Furthermore, since the forklift 10 will pass through the center area N even when turning, conditions A1 and A2 are satisfied regardless of the direction of the estimated trajectory T when an object is present in the center area N.

[0079] Whether condition A3 is satisfied can be determined based on the vehicle speed calculated by the main control unit 31. The main control unit 31 determines that the forklift 10 is stopped when the vehicle speed is equal to or less than the stop determination threshold [km / h]. The stop determination threshold is set to a value that indicates that the forklift 10 is stopped, and can be set to any value between 0 [km / h] and 0.5 [km / h], for example.

[0080] like Figure 10As shown, the start restriction state S2 is a state in which starting the forklift 10 from a stopped state is prohibited by setting the vehicle speed limit to 0. Starting refers to transitioning the forklift 10 from a stopped state to a traveling state. When a vehicle speed limit is set, the main control device 31 controls the forklift 10 so that its speed does not exceed the vehicle speed limit. For example, if the target speed calculated from the accelerator opening is less than the vehicle speed limit, the main control device 31 calculates the target rotational speed based on the target speed calculated from the accelerator opening. On the other hand, if the target speed calculated from the accelerator opening is greater than the vehicle speed limit, the main control device 31 calculates the target rotational speed using the vehicle speed limit instead of the target speed. Furthermore, the main control device 31 provides an instruction to the travel control device 43 to align the target rotational speed with the rotational speed of the travel motor 41. When the vehicle speed limit is 0, travel of the forklift 10 is prohibited. The main control device 31 permits travel below the vehicle speed limit, while restricting travel at speeds exceeding the vehicle speed limit. The main control device 31 functions as a speed limiter that limits the speed according to the vehicle speed upper limit value. In the start restriction state S2, the alarm device 58 issues an alarm.

[0081] like Figure 9 As shown, when the main control device 31 is in the start restriction state S2, if the start restriction release condition is met, the main control device 31 transitions from the start restriction state S2 to the normal control state S10. The start restriction release condition being met means that at least one of the following conditions B1, B2, and B3 is met.

[0082] Condition B1: There is no object in the restricted start area AA1.

[0083] Condition B2: The detection result of the direction sensor 35 is forward movement.

[0084] Condition B3: The direction sensor 35 detects that the direction of the area N, NL, or NR where the object is located is not consistent with the direction of the estimated trajectory T.

[0085] Conditions B1, B2, and B3 can be obtained by Figure 12 The table shown is used to represent this. Figure 12 The corresponding relationship between the regions N, NL, and NR where the object exists and the detection results and the estimated trajectory T of the direction sensor 35 when the conditions B1, B2, and B3 are satisfied is shown. Figure 12 The "all", "turn right" and "turn left" shown are Figure 11 Same meaning. Figure 12As shown, if there is no object in the start restricted area AA1, condition B1 holds regardless of the detection result of the direction sensor 35. Even if there is an object in the start restricted area AA1, condition B2 holds if the detection result of the direction sensor 35 indicates forward movement. Even if there is an object in the start restricted area AA1, condition B3 holds if the direction of the object's area N, NL, or NR does not match the direction of the predicted trajectory T. It can be said that the start restriction release condition is satisfied when at least one of conditions A1 or A2 fails to hold.

[0086] like Figure 9 As shown, when the main control device 31 is in the start restriction state S2, if the start prohibition condition is met, the main control device 31 transitions from the start restriction state S2 to the start prohibition state S3. The start prohibition condition being met means that both the following conditions C1 and C2 are met. Furthermore, if both the start prohibition condition and the start restriction release condition are met, the main control device 31 prioritizes the start restriction release condition and transitions to the normal control state S10.

[0087] Condition C1: The detection result of the direction sensor 35 is other than neutral.

[0088] Condition C2…Accelerator on.

[0089] Condition C1 is satisfied when the direction sensor 35 detects forward or reverse movement. In the start-restricted state S2, if the direction sensor 35 detects forward movement, the main control unit 31 transitions to the normal control state S10 due to the satisfaction of condition B2. Therefore, it can be said that condition C1 is essentially satisfied when the direction sensor 35 detects reverse movement.

[0090] Accelerator-on means that the operator of the forklift 10 has operated the accelerator pedal 16. Operation of the accelerator pedal 16 can be determined based on the detection result of the acceleration sensor 34. Accelerator-on also includes operation of the accelerator pedal 16 within the play (dead zone) of the accelerator pedal 16.

[0091] like Figure 10As shown, the start-inhibited state S3 is a state in which the forklift 10 is prohibited from starting by setting the vehicle speed limit to 0. The start-inhibited state S3 can be said to be a state in which the same speed limit as the start-restricted state S2 is applied. The start-inhibited state S3 and the start-restricted state S2 differ in the manner in which they transition to other states, such as whether or not the transition to the normal control state S10 is permitted. Furthermore, in the start-inhibited state S3, the alarm of the alarm device 58 can be made louder than in the start-restricted state S2. Examples of increasing the alarm intensity include increasing the volume of the buzzer if the alarm device 58 is a buzzer, or switching from a single alarm to both if the alarm device 58 is a combination of a light and a buzzer. This makes it easier for the operator to recognize the presence of an object within the predicted trajectory T.

[0092] like Figure 9 As shown, when the main control device 31 is in the start inhibited state S3, if the forced operation condition is satisfied, the main control device 31 transitions from the start inhibited state S3 to the forced operation state S4. The satisfied forced operation condition means that the following condition D1 is satisfied.

[0093] Condition D1…Accelerator off.

[0094] Accelerator-off means that the operator of the forklift 10 has not operated the accelerator pedal 16. Whether the accelerator pedal 16 has not been operated can be determined based on the detection result of the acceleration sensor 34. It can be said that the condition D1 is satisfied because the condition C2 is not satisfied.

[0095] like Figure 10 As shown, the forced operation state S4 is a state in which the speed of the forklift 10 is limited by setting the upper speed limit to VS1 [km / h]. VS1 is a value greater than 0 and is lower than the maximum speed that the forklift 10 can reach. It can be said that the main control device 31 allows the forklift 10 to travel at speeds below VS1. For example, the speed allowed for the forklift 10 to retreat is set as VS1. In addition, in the forced operation state S4, no restrictions are imposed on acceleration and deceleration. In the forced operation state S4, an alarm is issued by the alarm device 58. In the forced operation state S4, the alarm of the alarm device 58 can also be weakened compared to the start prohibition state S3.

[0096] like Figure 9 As shown, when the main control device 31 is in the forced operation state S4, if the forced operation release condition is satisfied, the main control device 31 transitions from the forced operation state S4 to the normal control state S10. The forced operation release condition is satisfied when all of the following conditions E1, E2, and E3 are satisfied.

[0097] Condition E1 . . . At least one of conditions B1 , B2 , and B3 is met.

[0098] Condition E2: The detection result of the direction sensor 35 is different from the previous value.

[0099] Condition E3: The forklift 10 is traveling.

[0100] Condition E1 is similar to the start restriction release condition. Condition E2 is satisfied when the direction sensor 35's detection result changes from forward to neutral, from forward to reverse, from neutral to forward, from neutral to reverse, from reverse to neutral, or from reverse to forward, due to operation of the steering lever 17. Condition E3 can be determined based on vehicle speed. The main control unit 31 determines that the forklift 10 is traveling if the vehicle speed exceeds the stop determination threshold [km / h].

[0101] When the main control device 31 is in the forced operation state S4, if the forced operation pre-release condition is met, the main control device 31 transitions from the forced operation state S4 to the forced operation pre-release state S5. The forced operation pre-release condition being met means that the following condition F1 is met. Furthermore, if both the forced operation release condition and the forced operation pre-release condition are met, the main control device 31 prioritizes the forced operation release condition and transitions to the normal control state S10.

[0102] Condition F1 . . . At least one of conditions B1 , B2 , and B3 is satisfied.

[0103] The forced action pre-release condition can be said to be the same as the start restriction release condition.

[0104] like Figure 10 As shown, the forced action pre-release state S5 means that the speed limit is released, and on the other hand, the acceleration upper limit value is set to AS1 [m / s 2] and the acceleration is restricted. AS1 is a value greater than 0, which 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 the acceleration restriction is applied, the main control device 31 controls so that the acceleration of the forklift 10 does not exceed the acceleration upper limit. For example, the main control device 31 sends an instruction indicating the target rotation speed and an instruction indicating the target acceleration to the travel control device 43. The travel control device 43 controls the rotation speed of the travel motor 41 based on the target rotation speed and the target acceleration so that the acceleration of the forklift 10 becomes the target acceleration. If the acceleration upper limit is set, the main control device 31 sends the acceleration upper limit as the target acceleration to the travel control device 43. In this way, the main control device 31 can impose an acceleration restriction on the forklift 10. The main control device 31 allows acceleration below the acceleration upper limit, and on the other hand, restricts acceleration exceeding the acceleration upper limit. The main control device 31 functions as a speed limiter that limits the speed according to the acceleration upper limit. In the forced operation preliminary release state S5 , no alarm is issued by the alarm device 58 .

[0105] like Figure 9 As shown, when the main control device 31 is in the forced operation pre-release state S5, if the forced operation formal release condition is satisfied, the main control device 31 transitions to the normal control state S10. The forced operation formal release condition is satisfied when at least one of the following conditions G1 and G2 is satisfied.

[0106] Condition G1: The vehicle speed of the forklift 10 reaches a value obtained by subtracting a first predetermined value from a target vehicle speed.

[0107] Condition G2…Accelerator off.

[0108] Condition G1 can be said to be that the difference between the target speed and the speed of the forklift 10, or the speed deviation, is less than a first predetermined value. In the forced action pre-release state S5, the acceleration limit is applied, which reduces the speed tracking performance of the forklift 10 and makes it difficult for the forklift 10 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 when the acceleration limit is applied. The first predetermined value can be set to any value between 0.5 km / h and 2.0 km / h, for example.

[0109] When the main control device 31 is in the forced operation pre-release state S5 , if the start restriction condition is satisfied, the main control device 31 transitions to the start restriction state S2 .

[0110] By causing the main control device 31 to perform the start restriction control as described above, the speed is restricted as follows when the forklift 10 is started.

[0111] When the forklift 10 is in a stopped state and Figure 12 When the correspondence in the table shown holds, the main control device 31 is in the normal control state S10. When there is no object within the start restriction area AA1 and within the expected trajectory T, the speed limit of the forklift 10 is not imposed. Since the main control device 31 does not impose a speed limit, the operator of the forklift 10 can start the forklift 10. When there is no object within the start restriction area AA1, the forklift 10 is allowed to start because there is no object that would obstruct the movement of the forklift 10. In the forklift 10 of this embodiment, when the forklift 10 is reversed, an object that obstructs the movement of the forklift 10 is detected, and the driver is prompted to avoid the object. Therefore, even if the forklift 10 is stopped and there is an object in the start restriction area AA1, the operator of the forklift 10 can start the forklift 10 when attempting to move the forklift 10 forward.

[0112] exist Figure 11 If the correspondence in the table shown holds true, that is, if the direction sensor 35 detects a direction other than forward while an object is within the predicted trajectory T, the main control unit 31 enters the start restriction state S2, prohibiting the forklift 10 from starting. In the start restriction state S2, the operator may not recognize the presence of an object within the predicted trajectory T and may be attempting to start the forklift 10 in the reverse direction. Therefore, the main control unit 31 prohibits the forklift 10 from starting. If the operator recognizes the presence of an object within the predicted trajectory T and changes the steering angle or the forward direction, eliminating the object from the predicted trajectory T, the main control unit 31 transitions to the normal control state S10, permitting the forklift 10 to start.

[0113] If the operator attempts to start the forklift 10 in reverse while maintaining the start restriction state S2 and operates the accelerator pedal 16, the main control device 31 transitions to the start restriction state S3. When the main control device 31 transitions to the start restriction state S3, it is deemed that the operator of the forklift 10 has not recognized the presence of an object within the predicted trajectory T, and the alarm of the alarm device 58 is amplified. This notifies the operator of the forklift 10 that an object is within the predicted trajectory T. In the start restriction state S2 and the start restriction state S3, the vehicle speed upper limit is set to 0, thereby prohibiting travel of the forklift 10. When the main control device 31 transitions to the start restriction state S2 or the start restriction state S3, the main control device 31 functions as a start restriction control unit.

[0114] If the operator releases the accelerator pedal 16 after the main control device 31 transitions to the start inhibited state S3 , the accelerator pedal 16 is released, and thus it is determined that the operator of the forklift 10 has recognized the presence of an object within the estimated trajectory T. Consequently, the main control device 31 transitions to the forced operation state S4 .

[0115] In the forced operation state S4, even if an object is present in the start restriction area AA1, the start of the forklift 10 is permitted. Specifically, if the forklift operator is determined to have recognized the presence of an object in the start restriction area AA1, the operator is deemed to be able to start the forklift 10 while avoiding the object, and the start of the forklift 10 is permitted. In the forced operation state S4, the upper speed limit is set to VS1, thereby setting a limit value to permit travel of the forklift 10. When the main control unit 31 transitions to the forced operation state S4, the main control unit 31 functions as a start permission control unit. Furthermore, when the main control unit 31 transitions to the forced operation state S4, the main control unit 31 functions as a first permission control unit.

[0116] If the object is no longer within the start-restricted area AA1 due to the movement of at least one of the forklift 10 and the object, the main control device 31 transitions to the forced action pre-release state S5. Acceleration is limited in the forced action pre-release state S5. In the forced action pre-release state S4, due to the speed limit, speed deviation may increase. Therefore, by placing the forced action pre-release state S5 between the forced action state S4 and the normal control state S10 before transitioning from the forced action state S4, the forklift 10 is accelerated slowly. In the forced action state S4, if the detection result of the direction sensor 35 changes from the previous value due to the operator's operation of the steering lever 17, the main control device 31 transitions to the normal control state S10. In the forced action pre-release state S5, the acceleration upper limit is set to AS1, thereby setting a limit value to allow the forklift 10 to travel. Furthermore, since the forced action pre-release state S5 is a state that transitions through the forced action state S4, it can be said that the operator of the forklift 10 has recognized the presence of an object when the state transitions to the forced action pre-release state S5. When the main control device 31 transitions to the forced operation pre-release state S5, the main control device 31 functions as a start permission control unit. Furthermore, when the main control device 31 transitions to the forced operation pre-release state S5, the main control device 31 functions as a second permission control unit.

[0117] If the forklift 10 accelerates while maintaining the forced action pre-release state S5 and the speed deviation decreases, the main control device 31 transitions to the normal control state S10. In the forced action pre-release state S5, acceleration is restricted, making efficient acceleration impossible. If efficient acceleration is desired, the forced action pre-release state S5 can be released by turning off the accelerator, thereby improving operability. Furthermore, before transitioning from the forced action pre-release state S5 to the normal control state S10, if the start restriction condition is met again, the main control device 31 transitions to the start restriction state S2.

[0118] As described above, the start restriction control functions when the forklift 10 attempts to start from a stopped state. In the start restriction control, when the forklift 10 is stopped and within the start restriction area AA1 and an object is present within the predicted trajectory T, the start of the forklift 10 is restricted by setting the vehicle speed limit to 0. This can be said to be a way of limiting the speed of the forklift 10 when it is traveling toward an object, thereby preventing the forklift 10 from approaching the object.

[0119] Next, the automatic deceleration control will be described.

[0120] The automatic deceleration control includes travel restriction control for stopping the forklift 10 and vehicle speed restriction control for allowing the forklift 10 to travel at a speed equal to or lower than an upper speed limit.

[0121] like Figure 13 As shown, in the travel restriction 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.

[0122] The normal control state S10 is the same state as the normal control state S10 in the start restriction control.

[0123] 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 transitions to the pre-travel restriction state S11. The pre-travel restriction condition being satisfied means that both of the following conditions H1 and H2 are satisfied.

[0124] Condition H1: There is a person in the alarm area.

[0125] Condition H2: The forklift 10 is traveling in the reverse direction.

[0126] The warning area is an area within the automatic deceleration area AA2 that is separate from the area where the speed limit is applied. The warning area is an area set so that the warning device 58 can issue a warning before a person enters the predicted trajectory T. The warning area in condition H1 can be the entire automatic deceleration area AA2 excluding the predicted trajectory T, or it can be an area extending from the predicted trajectory T to a predetermined range outside of the predicted trajectory T.

[0127] Whether the forklift 10 is traveling in the reverse direction can be determined based on the vehicle speed and travel direction calculated by the main control device 31. The main control device 31 determines that the forklift 10 is traveling in the reverse direction when the forklift 10 is traveling in the reverse direction and the vehicle speed is higher than the stop determination threshold.

[0128] 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, acceleration limit, and deceleration limit are not applied. In addition, the alarm in the pre-travel restriction state S11 is not issued when the forklift 10 switches back. Switching back refers to the action of switching from forward to reverse or from reverse to forward by operating the steering 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 switch flag to on. When the switch flag is on, the main control device 31 does not issue an alarm through the alarm device 58 even if the state changes to the pre-travel restriction state S11. The switch flag is released when the main control device 31 changes from the pre-travel restriction state S11 to another state.

[0129] When the main control device 31 is in the pre-travel restriction state S11, if the pre-travel restriction release condition is satisfied, the main control device 31 transitions to the normal control state S10. The pre-travel restriction release condition being satisfied means that at least one of the following conditions I1 and I2 is satisfied.

[0130] Condition I1: There is no person within the predicted trajectory T and the warning area.

[0131] Condition I2: Travel in the reverse direction has stopped and no reverse operation has been performed.

[0132] Stopping reverse travel means that the forklift 10's speed changes from being above the stop determination threshold to being below the stop determination threshold. In other words, the forklift 10, which is in motion, stops. A state in which no reverse operation is being performed means that at least one of the following conditions holds: the accelerator pedal 16 is not being operated, and the direction sensor 35 is not detecting a reverse direction. A state in which the direction sensor 35 is not detecting a reverse direction means that the direction sensor 35 is detecting a neutral or forward direction.

[0133] 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 transitions to the travel restriction state S12. The travel restriction condition being satisfied means that both of the following conditions J1 and J2 are satisfied.

[0134] Condition J1: There is a person within the predicted trajectory T.

[0135] Condition J2: The forklift 10 is traveling in the reverse direction.

[0136] Whether condition J1 holds true can be determined based on the person's X and Y coordinates. Since the predicted trajectory T is defined by the X and Y coordinates, the person's presence within the predicted trajectory T can be determined based on the person's X and Y coordinates. Since the predicted trajectory T is derived within the automatic deceleration area AA2, if a person is present within the predicted trajectory T, it can be said that the person is both within the automatic deceleration area AA2 and within the predicted trajectory T. Condition J2 is the same as condition H2.

[0137] like Figure 10 As shown, the travel restriction state S12 is a state in which the forklift 10 is decelerated and stopped by setting the vehicle speed upper limit to 0. In the travel restriction state S12 of this embodiment, no deceleration restriction is applied. In the travel restriction state S12, the deceleration upper limit is set to DS1 [m / s 2 ]. DS1 is a value greater than 0, which is a value lower than the maximum deceleration of the forklift 10. The main control device 31 allows the deceleration of the forklift 10 below DS1. When a deceleration limit is applied, the main control device 31 controls so that the deceleration of the forklift 10 does not exceed the deceleration upper limit value. For example, the main control device 31 sends an instruction indicating a target rotation speed and an instruction indicating a target deceleration to the travel control device 43. The travel control device 43 controls the travel motor 41 based on the target rotation speed and the target deceleration so that the deceleration of the forklift 10 becomes the target deceleration. If the deceleration upper limit value is set, the main control device 31 sends the deceleration upper limit value as the target deceleration to the travel control device 43. In this way, the main control device 31 can impose a deceleration limit on the forklift 10. In the travel restriction state S12, an alarm is issued by the alarm device 58. In addition, when the operator performs a deceleration operation, the main control device 31 gives priority to the operator's deceleration operation and does not limit the deceleration. Examples of the deceleration operation include accelerator OFF, operation of the steering lever 17 to the neutral position, braking operation, and turning operation.

[0138] like Figure 13As 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 transitions to the normal control state S10. The driving restriction release condition being satisfied means that the following condition K1 is satisfied.

[0139] Condition K1: Travel in the reverse direction has stopped and no reverse operation has been performed.

[0140] Condition K1 is the same as condition I2.

[0141] 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 transitions to the travel restriction pre-release state S13. The travel restriction pre-release condition being satisfied means that both of the following conditions L1 and L2 are satisfied.

[0142] Condition L1: There is no person within the predicted trajectory T.

[0143] Condition L2: The forklift 10 is traveling in the reverse direction.

[0144] It can be said that condition L1 is satisfied when condition J1 is not satisfied. Condition L2 is the same as condition H2.

[0145] like Figure 10 As shown, the driving restriction pre-release state S13 is a state in which the vehicle speed limit is released but the acceleration limit is applied. The main control device 31 sets the acceleration upper limit value to AS2 [m / s 2 ], and control is performed so that the acceleration of the forklift 10 does not exceed AS2. AS2 is a value greater than 0 and is lower than the maximum acceleration achievable by the forklift 10. AS2 may be the same as or different from AS1. In the travel restriction pre-release state S13, no warning is issued by the warning device 58.

[0146] like Figure 13 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 met, the main control device 31 transitions to the normal control state S10. The driving restriction formal release condition is met when at least one of the following conditions M1 and M2 is met.

[0147] Condition M1: The vehicle speed of the forklift 10 reaches a value obtained by subtracting a second predetermined value from the target vehicle speed.

[0148] Condition M2: No back-off operation has been performed.

[0149] It can be said that the condition M1 is that the difference between the target vehicle speed and the vehicle speed of the forklift 10, that is, the speed deviation, is smaller than a second prescribed value. In the travel restriction pre-release state S13, since the acceleration restriction is being executed, the speed followability of the forklift 10 is reduced, and the vehicle speed of the forklift 10 is not easily brought to the target vehicle speed intended by the operator. The second prescribed value is set in order to determine that the vehicle speed of the forklift 10 has reached the target vehicle speed intended by the operator in a state in which the acceleration restriction is being executed. As the second prescribed value, for example, an arbitrary value can be set from 0.5 [km / h] to 2.0 [km / h]. The second prescribed value can be the same value as the first prescribed value, or can be a different value from the first prescribed value.

[0150] When the main control device 31 is in the travel restriction pre-release state S13, if the travel restriction condition is established, the main control device 31 shifts to the travel restriction state S12. Similarly, when the main control device 31 is in the normal control state S10, if the travel restriction condition is established, the main control device 31 shifts to the travel restriction state S12.

[0151] Further, as described above, the higher the vehicle speed of the forklift 10, the more the main control device 31 lengthens the predicted trajectory T in the advancing direction. When the main control device 31 shifts to the travel restriction state S12 and shortens the predicted trajectory T in the advancing direction as the vehicle speed of the forklift 10 decreases, it is possible that a person will be outside the predicted trajectory T. In this case, the main control device 31 alternately shifts between the travel restriction state S12 and the travel restriction pre-release state S13 regardless of whether the forklift 10 approaches the person or not. In order to suppress this situation, the main control device 31 maintains the length of the predicted trajectory T in the advancing direction, that is, the trajectory derivation threshold value YT, regardless of the vehicle speed of the forklift 10 when it is detected that a person is present within the predicted trajectory T. The maintenance of the trajectory derivation threshold value YT is released, for example, when the person is no longer present within the predicted trajectory T.

[0152] The main control device 31 performs the travel restriction control as described above, and in the travel of the forklift 10, the speed restriction is performed as follows.

[0153] When a person enters the warning area while the forklift 10 is traveling, the main control device 31 transitions to the pre-travel restriction state S11. The main control device 31 uses the alarm device 58 to alert the operator that a person may enter the predicted trajectory T. If the operator turns the forklift 10 away from the person or stops the forklift 10 without reversing, the main control device 31 transitions to the normal control state S10. If a person enters the predicted trajectory T while the main control device 31 is in the pre-travel restriction state S11, the main control device 31 transitions to the travel restriction state S12. The main control device 31 sets the vehicle speed limit to 0, causing the forklift 10 to stop. At this time, the deceleration limit DS1 is set, limiting the deceleration, allowing the forklift 10 to stop slowly.

[0154] After the main control device 31 transitions to the restricted travel state S12, the forklift 10 stops. If the operator does not perform a reverse operation, the main control device 31 transitions to the normal control state S10. If the restricted travel condition is met while the main control device 31 is in the normal control state S10, the main control device 31 transitions to the restricted travel state S12 without passing through the pre-restricted travel state S11. Situations where the pre-restricted travel condition is met but the restricted travel condition is met include, for example, a high speed of the forklift 10 or an object entering the predicted trajectory T from a blind spot within the object detection range of the object detection unit 51.

[0155] If, while the main control device 31 is in the restricted travel state S12, no more people are within the predicted trajectory T before the forklift 10 stops, the main control device 31 transitions to the restricted travel state S13. Furthermore, if a person reenters the predicted trajectory T after transitioning to the restricted travel state S13, the main control device 31 transitions to the restricted travel state S12. In the restricted travel state S13, acceleration is restricted. Because speed limits are applied in the restricted travel state S12, speed deviations may increase. Therefore, by placing the restricted travel state S13 between the restricted travel state S12 and the normal control state S10 before transitioning from the restricted travel state S12 to the normal control state S10, the forklift 10 is accelerated more slowly.

[0156] If the forklift 10 accelerates while maintaining the travel restriction pre-release state S13 and the speed deviation decreases, the main control device 31 transitions to the normal control state S10. In the travel restriction pre-release state S13, the acceleration is restricted, making efficient acceleration impossible. To achieve efficient acceleration, the travel restriction pre-release state S13 can be released by turning off the accelerator, thereby improving operability.

[0157] As described above, when the object detection unit 51 detects a person and the person enters the estimated trajectory T, the travel restriction control is activated and the forklift 10 stops. In other words, the speed is restricted when the forklift 10 is traveling toward a person.

[0158] Next, the speed limit control is explained. The speed limit control is different 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 Figure 14 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.

[0159] like Figure 14 As 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.

[0160] like Figure 10 As shown, the restriction release state S21 is a state in which the vehicle speed restriction is not applied. In addition, in the restriction release state S21, no restriction is applied to the acceleration and deceleration.

[0161] like Figure 14 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 satisfaction of the pre-restriction start condition means that both the following conditions N1 and N2 are satisfied.

[0162] Condition N1: A person is present in the advance warning area in the automatic deceleration area AA2.

[0163] Condition N2: The forklift 10 is traveling in the reverse direction.

[0164] 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 sometimes not applied at a location far from the forklift 10. That is, within 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 that extends 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 an area where a speed upper limit value higher than the speed of the forklift 10 is set. The advance warning zone is derived from the forklift 10's speed and a speed limit set based on the person's position, so that the time from when the person enters the advance warning zone to when they enter the speed limit zone is a predetermined set time. The predetermined set time is, for example, 1 to 3 seconds.

[0165] The pre-limit start state S22 is a state in which the alarm device 58 issues an alarm. The pre-limit start state S22 can be said to be a state for warning the operator of the possibility of a speed limit before the speed limit is applied. In the pre-limit start state S22, the speed limit, acceleration limit, and deceleration limit are not applied. In the pre-limit start state S22, similar to the pre-travel limit state S11, no alarm is issued when the forklift 10 is turning.

[0166] When the main control device 31 is in the pre-restriction start state S22, if the pre-restriction start cancellation condition is satisfied, the main control device 31 transitions to the restriction cancellation state S21. The pre-restriction start cancellation condition is that at least one of the following conditions O1 and O2 is satisfied.

[0167] Condition O1: No person exists in the speed limit area or the advance warning area.

[0168] Condition O2: Travel in the reverse direction has stopped and no reverse operation has been performed.

[0169] 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 P1 and P2 are satisfied.

[0170] Condition P1: A person is present in the speed limit area in the automatic deceleration area AA2.

[0171] Condition P2: The forklift 10 is traveling in the reverse direction.

[0172] like Figure 10 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 within the automatic deceleration area AA2. The shorter the distance between the forklift 10 and the person, the lower the speed limit is set. A map is stored in the storage unit 33 of the main control unit 31 or in a storage medium such as an external storage device, which maps the speed limit to the distance between the forklift 10 and the person. The main control unit 31 sets the mapped value, which corresponds to the speed limit, as the speed limit. The speed limit is not limited to decreasing in proportion to the decrease in the distance between the forklift 10 and the person; it is sufficient that the speed limit decreases as the distance between the forklift 10 and the person decreases. If multiple people are present in the speed restriction area within the automatic deceleration area AA2, the speed limit is determined based on the position of the person closest to the forklift 10.

[0173] In the restriction start state S23, the deceleration limit is applied. In the restriction start state S23, the deceleration upper limit is set to DS2 [m / s 2 DS2 is a value greater than 0 and is lower than the maximum deceleration of the forklift 10. DS2 may be the same as or different from DS1. Furthermore, as in the case of the restricted travel state S12, if the operator performs a deceleration operation, the main control unit 31 may prioritize the operator's deceleration operation and not restrict the deceleration.

[0174] like Figure 14 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 transitions to the restriction release state S21. The satisfaction of the restriction start release condition means that the following condition Q1 is satisfied. Furthermore, 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 transitions to the restriction start state S23.

[0175] Condition Q1: Travel in the reverse direction has stopped and no reverse operation has been performed.

[0176] 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 satisfaction of the restriction pre-release condition means that the following condition R1 is satisfied.

[0177] Condition R1: No person is present in the speed limit area in the automatic deceleration area AA2.

[0178] like Figure 10 As shown, the restriction pre-release state S24 means that the vehicle speed limit is released but the acceleration upper limit is set to AS3 [m / s 2] and acceleration is limited. AS3 is a value greater than 0 and is lower than the maximum acceleration achievable by the forklift 10. The main control unit 31 allows acceleration of the forklift 10 below AS3. AS3 can be the same as AS1 and AS2, or different from AS1 and AS2.

[0179] like Figure 14 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 S1 is satisfied.

[0180] Condition S1: A person is present in the speed limit area in the automatic deceleration area AA2.

[0181] 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 T1 and T2 is satisfied.

[0182] Condition T1: The vehicle speed of the forklift 10 reaches a value obtained by subtracting a third predetermined value from the target vehicle speed.

[0183] Condition T2: No back-off operation has been performed.

[0184] Condition T1 can be said to be that the difference between the target speed and the speed of the forklift 10, that is, the speed deviation, is less than the third prescribed value. In the restriction pre-release state S24, due to the acceleration restriction, the speed followability of the forklift 10 is reduced, and the speed of the forklift 10 is less likely to reach the target speed. The third prescribed 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 third prescribed value, for example, any value can be set from 0.5 [km / h] to 2.0 [km / h]. The third prescribed value can be the same as the first prescribed value and the second prescribed value, or a value different from the first prescribed value and the second prescribed value.

[0185] Furthermore, 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.

[0186] The main control device 31 performs the vehicle speed limit control for humans as described above, thereby limiting the speed of the forklift 10 as follows during travel.

[0187] During the travel of the forklift 10, if a person enters the pre-alarm area, the main control device 31 transitions to the pre-restriction start state S22. The main control device 31 uses the alarm device 58 to alert the operator that the person may enter the predicted trajectory T. 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 transitions to the restriction release state S21. When a person enters the speed limit area while the main control device 31 is in the pre-restriction start state S22, the main control device 31 transitions to the restriction start state S23. The main control device 31 sets the vehicle speed upper limit to a value corresponding to the map. At this time, by setting the deceleration upper limit DS2, the deceleration is also limited, so the forklift 10 decelerates slowly.

[0188] In the restriction start state S23, although the vehicle speed limit is set, the forklift 10 is allowed to travel at speeds below the vehicle speed limit. The operator can drive the forklift 10 while avoiding people. If the restriction start cancellation condition is met while the main control device 31 is in the restriction start state S23, the main control device 31 transitions to the restriction cancellation state S21 to cancel the vehicle speed limit.

[0189] If the operator continues driving the forklift 10 while maintaining the restriction start state S23 and no one is present in the speed limit area, the main control device 31 transitions to the restriction pre-release state S24. The speed limit is thereby released. In the restriction pre-release state S24, acceleration is restricted. Since the speed limit is applied in the restriction start state S23, speed deviation may increase. Therefore, by placing the restriction pre-release state S24 between the restriction start state S23 and the restriction release state S21 before transitioning from the restriction start state S23, the forklift 10 is accelerated slowly.

[0190] When the forklift 10 accelerates while maintaining the restriction pre-release state S24 and the speed deviation decreases, the main control device 31 transitions to the restriction release state S21. In the restriction pre-release state S24, due to the restrictions on acceleration, it is not possible to accelerate efficiently. When it is desired to accelerate efficiently, the restriction pre-release state S24 can be released by turning off the accelerator, thereby improving 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 transitions to the restriction release state S21. In addition, if a person enters the speed limit area again before transitioning from the restriction pre-release state S24 to the restriction release state S21, the main control device 31 transitions to the restriction start state S23.

[0191] As described above, when the object detection unit 51 detects a person while the forklift 10 is traveling, the speed limit control for the person is activated within the automatic deceleration area AA2 and outside the predicted trajectory T, thereby decelerating the forklift 10 .

[0192] Next, the vehicle speed limit control when the object is an obstacle will be described. Below, the differences from the vehicle speed limit control when the object is a person will be described, and the similarities with the vehicle speed limit control when the object is a person will be omitted.

[0193] The pre-restriction start condition being satisfied when the object is an obstacle means that both of the following conditions U1 and U2 are satisfied.

[0194] Condition U1: An obstacle exists in the advance warning area in the automatic deceleration area AA2.

[0195] Condition U2: The forklift 10 is traveling in the reverse direction.

[0196] The speed limit area when the object is an obstacle is the 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. The advance warning area is an area that exists farther than 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 to 3 seconds. When the object is an obstacle, the advance warning area is, for example, any one of an area farther than the speed limit area within the expected trajectory T, an area outside the expected trajectory T and on an extension of the expected trajectory T, and an area including both.

[0197] The conditions for the preliminary restriction start release condition, the first restriction start condition, the restriction start release condition, the preliminary restriction release condition, the second restriction start condition, and the final restriction release condition when the object is an obstacle are those after a person is changed into an obstacle.

[0198] Furthermore, when the object is an obstacle, the shorter the distance from the forklift 10 to the obstacle, the lower the speed limit applied to the forklift 10. A map is stored in the storage unit 33 of the main control unit 31 or in a storage medium such as an external storage device, which maps the speed limit to the distance from the forklift 10 to the obstacle. The main control unit 31 sets the speed limit based on the map. Furthermore, the speed limit is not limited to decreasing in proportion to the decrease in the distance from the forklift 10 to the obstacle; any correlation is sufficient: as the distance from the forklift 10 to the obstacle decreases, the speed limit decreases. Furthermore, the speed limit applied when the object is an obstacle is higher than the speed limit applied when the object is a person. Specifically, if the distance from the forklift 10 is the same, the speed limit is set to a higher value when the object is an obstacle than when the object is a person.

[0199] By causing the main control device 31 to perform the vehicle speed limit control for the obstacle as described above, the speed of the forklift 10 is limited as follows during travel.

[0200] During the travel of the forklift 10, if an obstacle enters the pre-alarm area, the main control device 31 transitions to the pre-restriction start state S22. The main control device 31 alerts the operator of the nearby obstacle 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 reversing, the main control device 31 transitions to the restriction release state S21. If an obstacle enters the speed limit area while the main control device 31 is in the pre-restriction start state S22, the main control device 31 transitions to the restriction start state S23. The main control device 31 sets the vehicle speed upper limit to a value corresponding to the map. At this time, the deceleration is also limited by setting the deceleration upper limit DS2. Therefore, the forklift 10 decelerates slowly.

[0201] In the restriction start state S23, although the speed limit is set, the forklift 10 is allowed to travel at speeds below the speed limit. The operator can operate the forklift 10 while avoiding obstacles. If the restriction start release condition is met while the main control device 31 is in the restriction start state S23, the main control device 31 transitions to the restriction release state S21 to release the speed limit. If the object is an obstacle, the speed limit area is set within the predicted trajectory T, making it easier to meet the restriction start release condition than if the object is a person.

[0202] As described above, in a state where the forklift 10 is running, when an obstacle is detected by the obstacle detection section 51, the speed limit control with respect to the obstacle functions, so that the speed limit is imposed when the obstacle enters the automatic deceleration area AA2 and the predicted trajectory T. On the other hand, in a case where the obstacle exists outside the predicted trajectory T, the speed limit is not imposed.

[0203] In the automatic deceleration control, in a case where a person exists within the predicted trajectory T, the upper limit value of the vehicle speed is set to 0. On the other hand, in a case where an obstacle exists within the predicted trajectory T, the upper limit value of the vehicle speed is set to a value higher than 0. In a case where a person exists outside the predicted trajectory T, the upper limit value of the vehicle speed is set to a value higher than 0. On the other hand, in a case where an obstacle exists outside the predicted trajectory T, the speed limit is not imposed. Therefore, it can be said that the main control device 31 sets the upper limit value of the vehicle speed lower in a case where the object is determined to be a person than in a case where the object is determined to be an obstacle. In addition, it can be said that the main control device 31 sets the upper limit value of the vehicle speed lower in a case where the object exists within the automatic deceleration area AA2 and the predicted trajectory T than in a case where the object exists within the automatic deceleration area AA2 and outside the predicted trajectory T. Further, the "setting the upper limit value of the vehicle speed lower" also includes a manner in which the upper limit value of the vehicle speed is set with respect to a state in which the upper limit value of the vehicle speed is not set. Whether the object exists within the predicted trajectory T or outside the predicted trajectory T, the manner in which the speed limit is imposed is not limited to the manner in which the speed limit is imposed, and the speed limit can not be imposed in a case where the object exists outside the predicted trajectory T as in the embodiment.

[0204] In the present embodiment, the start-up limit control, the running limit control, the speed limit control with respect to a person, and the speed limit control with respect to an obstacle are performed in parallel.

[0205] The start-up limit control is control for imposing a speed limit when the forklift 10 starts up from a state in which the forklift 10 is stopped. In a case where the forklift 10 is running, the transition from the normal control state S10 to the start-up limit state S2 is suppressed by the condition A3. When the main control device 31 transitions to the forced action state S4 due to the establishment of the forced action condition, the running of the forklift 10 at or below the upper limit value of the vehicle speed VS1 is permitted. When the main control device 31 transitions to the forced action pre-release state S5 due to the establishment of the forced action pre-release condition, the running of the forklift 10 at or below the upper limit value of the acceleration AS1 is permitted. In this way, the speed limit by the start-up limit control is performed in a first vehicle speed range having the vehicle speed at which the forklift 10 is stopped, that is, the vehicle speed 0, as a lower limit value. The upper limit value of the first vehicle speed range can vary depending on the vehicle speed in the forced action pre-release state S5. The main control device 31 that performs the start-up limit control functions as a first control section.

[0206] The travel restriction control is a control used to stop the forklift 10 from a traveling state. When the forklift 10 is stopped, the travel restriction condition J2 is not satisfied, preventing the main control unit 31 from transitioning to the travel restriction state S12. The speed restriction implemented by the travel restriction control is performed within a second speed range whose lower limit is the speed at which the forklift 10 is determined to be traveling, that is, a speed higher than the stop determination threshold. The lower limit of the second speed range can be said to be higher than the lower limit of the first speed range. The speed restriction implemented by the travel restriction control is performed while the forklift 10 is traveling. Therefore, while there is no upper limit to the second speed range, the maximum speed that the forklift 10 can actually reach is the upper limit of the second speed range.

[0207] The speed limit control for people and the speed limit control for obstacles are controls for decelerating the forklift 10 from a traveling state. When the forklift 10 is stopped, condition P2 of the first speed limit start condition is not satisfied, preventing the main control unit 31 from transitioning to the speed limit start state S23. Similar to the travel limit control, the speed limit implemented by the speed limit control for people and the speed limit control for obstacles is also implemented when the forklift 10 is within the second speed range. The main control unit 31 that performs the travel limit control, the speed limit control for people, and the speed limit control for obstacles functions as a second control unit.

[0208] As previously described, the start restriction control, driving restriction control, speed restriction control for people, and speed restriction control for obstacles are performed in parallel. Therefore, different speed limits and acceleration limits can be set for each control. If different speed limits are set for each control, the main control device 31 selects the lowest speed limit and applies speed restriction based on that speed limit. That is, if different speed limits are set for each control, the main control device 31 controls the forklift 10 so that its speed does not exceed the lowest speed limit. If different acceleration limits are set for each control, the main control device 31 selects the lowest acceleration limit and applies speed restriction based on that acceleration limit. Furthermore, if a speed limit is set for only one of the start restriction control and the automatic deceleration control, the main control device 31 applies speed restriction based on that speed limit. Similarly, if an upper acceleration limit value is set for only one of the start restriction control and the automatic deceleration control, the main control unit 31 performs speed limiting based on the upper acceleration limit value. Selecting a limit value includes a method in which, if a limit value is set for either the start restriction control or the automatic deceleration control and not for the other, the set limit value is selected and speed limiting is performed based on that limit value.

[0209] The main control device 31 repeatedly performs the following intervention control in a predetermined control cycle. The intervention control is a control for forcibly changing the state of the automatic deceleration control by intervening in the automatic deceleration control.

[0210] like Figure 15 As shown, in step S200, the main control device 31 determines whether the state of the start restriction control is the start restriction state S2. If the determination result of step S200 is affirmative, the main control device 31 proceeds to step S300. If the determination result of step S200 is negative, the main control device 31 proceeds to step S210.

[0211] In step S210, the main control device 31 determines whether the state of the start restriction control is the start prohibition state S3. If the determination result of step S210 is affirmative, the main control device 31 proceeds to step S300. If the determination result of step S210 is negative, the main control device 31 proceeds to step S220.

[0212] In step S220, the main controller 31 determines whether the start restriction control state is in the forced operation state S4. If the determination result of step S220 is affirmative, the main controller 31 proceeds to step S300. If the determination result of step S220 is negative, the main controller 31 proceeds to step S230.

[0213] In step S230, the main controller 31 determines whether the start restriction control state is the forced operation pre-release state S5. If the determination result of step S230 is affirmative, the main controller 31 proceeds to step S240. If the determination result of step S230 is negative, the main controller 31 proceeds to step S310.

[0214] In step S240, main control device 31 determines whether an object exists within the predicted trajectory T. Specifically, main control device 31 determines whether the detection result of direction sensor 35 indicates backward movement and whether the object-containing regions N, NL, and NR are aligned with the direction of predicted trajectory T. If the determination result of step S240 is negative, that is, if an object does not exist within the predicted trajectory T, main control device 31 proceeds to step S300. If the determination result of step S240 is positive, that is, if an object exists within the predicted trajectory T, main control device 31 proceeds to step S310.

[0215] In step S300, the main control device 31 intervenes in the automatic deceleration control. The main control device 31 transitions the state of the driving restriction control to the normal control state S10 and maintains this state. The main control device 31 transitions the state of the speed restriction control for people to the restriction-released state S21 and maintains this state. The main control device 31 transitions the state of the speed restriction control for obstacles to the restriction-released state S21 and maintains this state. In other words, regardless of the conditions for transitioning the automatic deceleration control state, such as the positional relationship between the forklift 10 and the object, the speed of the forklift 10, or other factors, the main control device 31 forcibly transitions the state and maintains this state.

[0216] In step S310, the main control device 31 cancels the intervention in the automatic deceleration control. If the intervention in the automatic deceleration control was carried out in the previous control cycle, the intervention in the automatic deceleration control is no longer carried out. If the intervention in the automatic deceleration control is not carried out, the state is maintained. Thus, the main control device 31 changes the state of the automatic deceleration control according to the conditions for changing the state of the automatic deceleration control. That is, the state is changed according to Figure 9 、 Figure 13 as well as Figure 14 The state transition diagram shown is used for transition.

[0217] The intervention control can be said to be control that intervenes in the automatic deceleration control when either a limit value prohibiting the forklift 10 from traveling is set by the start restriction control or a limit value permitting the forklift 10 from traveling is set by the start restriction control.

[0218] The operation of this embodiment will be described.

[0219] In the forced operation state S4, the forklift 10 is permitted to travel at speeds below the upper speed limit VS1. In the forced operation pre-release state S5, the forklift 10 is permitted to travel at accelerations below the upper speed limit AS1. Therefore, even if the upper speed limit VS1 is set in the forced operation state S4, or even if the upper acceleration limit AS1 is set in the forced operation pre-release state S5, the forklift 10 can travel. When the main control device 31 transitions to the forced operation state S4, an object is present around the forklift 10. Furthermore, when the main control device 31 transitions to the forced operation state S4, the main control device 31 determines that the operator has recognized the presence of an object due to the operator's accelerator-off operation. The forced operation pre-release state S5 is a state set in the forced operation state S4. Therefore, when the main control device 31 is in the forced operation state S4 or the forced operation pre-release state S5, the forklift 10 operator may recognize the presence of an object and perform an evasive action to avoid the object.

[0220] In the forced action state S4 and the forced action pre-release state S5, the forklift 10 can travel, so the conditions for transitioning to the automatic deceleration control state may be met. If a speed limit is set by the automatic deceleration control, and speed is limited based on this speed limit, this can hinder evasive maneuvers. The same applies if an acceleration limit is set by the automatic deceleration control and speed is limited based on this acceleration limit. For example, if the start restriction control state is in the forced action state S4 and the travel restriction control state is in the travel restriction state S12, speed limitation based on the lowest speed limit, 0, will occur, and the forklift 10 will stop. Suppose the start restriction control state is in the forced action state S4 and the speed limit control state is in the restriction start state S23, and the speed limit in the restriction start state S23 is lower than the speed limit VS1. In this case, if speed limitation is implemented based on the speed limit in the restriction start state S23, speed limitation will be implemented based on the speed limit lower than the speed limit VS1. When the start restriction control state is in the forced action pre-release state S5 and the travel restriction control state is in the travel restriction state S12, the speed is limited to the lowest speed limit of 0, and the forklift 10 stops. Suppose the start restriction control state is in the forced action pre-release state S5 and the speed limit control state is in the restriction pre-release state S24, and the acceleration limit AS3 is lower than the acceleration limit AS1. In this case, if the speed is limited according to the acceleration limit in the restriction pre-release state S24, the speed is limited to the acceleration limit AS3, which is lower than the acceleration limit AS1. Thus, even if the operator recognizes the object and takes evasive action, the speed and acceleration of the forklift 10 are still limited to a level higher than the speed limit of the start restriction control, hindering the evasive action.

[0221] In this embodiment, intervention control is implemented to prevent speed restriction through automatic deceleration control when an evasive maneuver is already in progress. Through intervention control, when the start restriction control is in the forced action state S4, the driving restriction control state is transitioned to the normal control state S10. The speed restriction control for humans and the speed restriction control for obstacles are transitioned to the restriction-released state S21. Normal control state S10 and restriction-released state S21 are states where neither the upper speed limit nor the upper acceleration limit is set. Therefore, the main control unit 31 selects the upper speed limit VS1 for the start restriction control and implements speed restriction to allow driving below the upper speed limit VS1.

[0222] By the intervention control, in a case where the state of the start limit control is the forced action pre-cancellation state S5 and there is no object within the predicted trajectory T, the state of the travel limit control is changed to the normal control state S10. The states of the person speed limit control and the obstacle speed limit control are changed to the limit cancellation state S21. Therefore, the main control device 31 selects the acceleration upper limit value AS1 of the start limit control, and performs speed limitation to allow acceleration of the acceleration upper limit value AS1 or less.

[0223] Effects of the present embodiment are described.

[0224] (1) In a case where the limit value is set by the start limit control, selection of the limit value of the automatic deceleration control as the limit value used for the speed limitation is suppressed. In a case where the limit value is set by the start limit control, it is possible to suppress the avoidance action of the fork truck 10 from being hindered by the limit value of the automatic deceleration control. Therefore, it is possible to suppress the decrease in workability.

[0225] (2) In a case where the state of the start limit control is the forced action pre-cancellation state S5 and there is no object within the predicted trajectory T, selection of the limit value of the automatic deceleration control as the limit value used for the speed limitation is suppressed. When the state of the main control device 31 is changed from the forced action state S4 to the forced action pre-cancellation state S5, the alarm by the alarm device 58 is no longer performed. Thereby, the operator of the fork truck 10 can judge that the avoidance action is completed even in a case where the avoidance action is not completed. In a case where there is an object within the predicted trajectory T, it is judged that the avoidance action is not performed, and the speed limitation by the automatic deceleration control is allowed. In a case where there is no object within the predicted trajectory T, it is conceivable that the avoidance action is still in progress. In a case where the avoidance action is still in progress, by suppressing selection of the limit value of the automatic deceleration control as the limit value used for the speed limitation, the avoidance action is suppressed from being hindered. By judging whether or not the speed limitation by the automatic deceleration control is allowed depending on whether or not the avoidance action is performed, it is possible to appropriately perform the speed limitation.

[0226] (3) When the start restriction control state changes to the start restriction state S2 or the start prohibition state S3, the main control device 31 intervenes in the automatic deceleration control and does not perform speed limitation based on the limit value of the automatic deceleration control. That is, even if the limit value that prohibits the travel of the forklift 10 is set by the start restriction control, the main control device 31 suppresses speed limitation through the automatic deceleration control. When the start restriction control state is the start restriction state S2 or the start prohibition state S3, the vehicle speed upper limit is 0, so even if the automatic deceleration control is not intervened, speed limitation through the automatic deceleration control is suppressed. However, because the start restriction control and the automatic deceleration control are intermittently performed according to a predetermined control cycle, speed limitation through the automatic deceleration control may occur when the start prohibition state S3 transitions to the forced operation state S4. When the start restriction control state changes to the start restriction state S2 or the start prohibition state S3, speed limitation through the automatic deceleration control is suppressed. As a result, speed limitation by the automatic deceleration control can be appropriately suppressed in the forced operation state S4 or the forced operation pre-release state S5.

[0227] (4) The main control device 31 sets a vehicle speed upper limit when an object is present within the predicted trajectory T. Specifically, in each of the start restriction control, the travel restriction control, the speed limit control for people, and the speed limit control for obstacles, a vehicle speed upper limit is set when an object is present within the predicted trajectory T. The main control device 31 controls the forklift 10 so that the vehicle speed does not exceed the vehicle speed upper limit. Even if the operator of the forklift 10 does not decelerate, the speed of the forklift 10 is set to be below the vehicle speed upper limit. This improves the operability of the forklift 10 operator.

[0228] (5) When an object is within the automatic deceleration area AA2 and within the predicted trajectory T, the main control device 31 sets the vehicle speed upper limit to a lower value than when the object is within the automatic deceleration area AA2 and outside the predicted trajectory T. In the embodiment, when the object is a person, the vehicle speed upper limit is set to 0 when the person is within the predicted trajectory T, and is set to a value greater than 0 when the person is outside the predicted trajectory T. When the object is an obstacle, the vehicle speed upper limit is set to a value greater than 0 when the obstacle is within the predicted trajectory T, and is not set when the obstacle is outside the predicted trajectory T.

[0229] If the vehicle speed limit is always set to the value that occurs when an object is present within the predicted trajectory T, operability will be reduced. For example, if the main control unit 31 sets the vehicle speed limit to 0 regardless of the predicted trajectory T when a person is present within the automatic deceleration area AA2, the forklift 10 will stop even if the person is in a position that does not hinder the forklift 10's movement. In this case, the forklift 10 will stop more frequently, resulting in reduced operability. Even when the object is an obstacle, operability will still be reduced. Forklifts 10 are often used in environments surrounded by a large number of objects. Moreover, in most cases, forklifts 10 make sharp turns more frequently than passenger cars and use stereo cameras with wider angles than those installed in passenger cars. Therefore, if the vehicle speed limit is always set to the value that occurs when an object is present within the predicted trajectory T, operability will be significantly reduced in the forklift 10.

[0230] In contrast, in the forklift 10 of the embodiment, even when an object is present within the automatic deceleration area AA2, a vehicle speed higher than the upper speed limit when the object is not present within the predicted trajectory T is permitted. Objects within the predicted trajectory T are more likely to obstruct the travel of the forklift 10 than objects outside the predicted trajectory T. Therefore, by relaxing the vehicle speed limit when no object is present within the predicted trajectory T, operability can be further improved.

[0231] (6) When the object detected by the object detection unit 51 is an obstacle, the upper speed limit is set higher than when the object is a person. The forklift 10 is often used in an environment with a large number of objects around it. Therefore, when the object is an obstacle, by increasing the permitted speed of the forklift 10, operability can be further improved. In particular, when the object is an obstacle and the obstacle is not within the predicted trajectory T, operability can be improved by not applying a speed limit.

[0232] (7) The obstacle detection device 55 can distinguish whether the object is a person or an obstacle. When the main control device 31 performs automatic deceleration control, the vehicle speed limit is lowered when the object is a person, compared to when the object is an obstacle. In the embodiment, when the person is within the expected trajectory T, the vehicle speed limit is set to 0, and when the obstacle is within the expected trajectory T, the vehicle speed limit is set to a value greater than 0. Similarly, when the person is outside the expected trajectory T, the vehicle speed limit is also set lower than when the obstacle is outside the expected trajectory T. The possibility of a person moving is higher than that of an obstacle, and there is a possibility of approaching the forklift 10. Therefore, when the object is a person, the vehicle speed limit is lowered compared to when the object is an obstacle, so as to remind the operator of the forklift 10 to avoid it.

[0233] (8) The host control device 31 sets the vehicle speed upper limit value to a value greater than 0 outside the predicted trajectory T and sets the vehicle speed upper limit value to 0 inside the predicted trajectory T in the case where the object is a person. In addition, the host control device 31 sets the vehicle speed upper limit value lower as the distance from the forklift 10 to the person is shorter in the case where the person is present outside the predicted trajectory T. The closer the person is to the forklift 10, the lower the vehicle speed of the forklift 10 is made, and thus the forklift 10 can be stopped slowly when the person enters inside the predicted trajectory T and the vehicle speed upper limit value is set to 0.

[0234] (9) The host control device 31 sets the vehicle speed upper limit value to 0 in the case where the object is present inside the predicted trajectory T within the start-up restriction region AA1. By setting the vehicle speed upper limit value to 0, the start-up of the forklift 10 is prohibited. In the case where the object is present inside the predicted trajectory T within the start-up restriction region AA1, the progress of the forklift 10 can be obstructed. In this case, by prohibiting the start-up of the forklift 10, the operator is prompted to change the progress direction or turn. Thus, the progress of the forklift 10 is suppressed from being obstructed, and further improvement of workability can be achieved.

[0235] (10) The higher the vehicle speed of the forklift 10, the more the host control device 31 extends the predicted trajectory T in the progress direction. The higher the vehicle speed of the forklift 10, the shorter the time until the object is reached. Thus, by extending the predicted trajectory T more as the vehicle speed of the forklift 10 is higher, appropriate vehicle speed restriction corresponding to the vehicle speed of the forklift 10 can be performed.

[0236] (11) The host control device 31 derives the predicted trajectory T based on the steering angle. If the forklift 10 turns, the host control device 31 derives the predicted trajectory T based on the turning direction of the forklift 10. Thus, the accuracy of the derived predicted trajectory T can be improved.

[0237] (12) The forklift 10 is provided with a cargo handling device 20 that loads a cargo. In the forklift 10 that loads a cargo, stability is required due to the relationship with the cargo to be loaded. By setting the vehicle speed upper limit value, the stability of the forklift 10 can be improved.

[0238] (13) The start-up restriction control is set with a forced operation state S4. The host control device 31 allows the start-up of the forklift 10 even in the case where the object is present inside the predicted trajectory T within the start-up restriction region AA1 when the forced operation state S4 is transitioned. If the start-up of the forklift 10 is always prohibited in the case where the object is present inside the predicted trajectory T within the start-up restriction region AA1, the forklift 10 can be prohibited from starting up even in the case where the forklift 10 can avoid the object and start up. By setting the vehicle speed upper limit value in the forced operation state S4, the forklift 10 is allowed to start up in a state where the vehicle speed is low, and further improvement of workability can be achieved.

[0239] (14) In the start restriction control, an alarm is issued by the alarm device 58 when an object is within the predicted trajectory T, and an alarm is not issued by the alarm device 58 when an object is outside the predicted trajectory T. In the travel restriction control, an alarm is issued by the alarm device 58 when a person is within the warning area, and an alarm is not issued by the alarm device 58 when a person is further away from the warning area. In the speed limit control for people and the speed limit control for obstacles, an alarm is issued by the alarm device 58 when an object is within the pre-warning area, and an alarm is not issued by the alarm device 58 when an object is further away from the pre-warning area. In this way, it can be said that the main control unit 31 limits the area within the object detection range of the object detection unit 51 where an alarm is issued by the alarm device 58. If an alarm is always issued by the alarm device 58 when an object is detected by the object detection unit 51, an alarm will be issued even if the object does not hinder the movement of the forklift 10. In this case, the operator will become accustomed to the alarm, and there is a possibility that the operator will not be able to recognize the object even if the object actually hinders the movement of the forklift 10. By limiting the alarm of the alarm device 58 , it is possible to prevent the operator from becoming accustomed to the alarm.

[0240] 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.

[0241] Alternatively, the main control device 31 may not perform the determinations in steps S200 and S210. Specifically, the main control device 31 may not intervene in the automatic deceleration control when the start restriction control state is in the start restriction state S2 or the start prohibition state S3. Since the forklift 10 is stopped when the start restriction control state is in the start restriction state S2 or the start prohibition state S3, it is conceivable that the automatic deceleration control will not impose a speed limit. Therefore, as long as the start restriction control at least sets a limit value that allows the forklift 10 to travel, the automatic deceleration control may be omitted.

[0242] Alternatively, in the forced operation state S4, the alarm device 58 may not issue an alarm. In this case, the main control device 31 may not limit the speed through the automatic deceleration control when the start restriction control state is the forced operation state S4 and there is no object within the estimated trajectory T. In other words, if the determination result of step S220 is affirmative, the determination of step S240 is performed, and if the determination result of step S240 is negative, the process of step S300 is performed.

[0243] Alternatively, the main control device 31 may not perform step S240. In this case, if the determination result of step S230 is affirmative, the main control device 31 performs step S300. If the determination result of step S230 is negative, the main control device 31 performs step S310. In other words, when the start restriction state is in the forced operation pre-release state S5, the main control device 31 controls the vehicle so that speed limitation of the automatic deceleration control is not performed, regardless of whether an object is present within the predicted trajectory T.

[0244] In this case, the speed limitation of the automatic deceleration control is performed only when the state of the start restriction control is the normal control state S10. Therefore, the operator of the forklift 10 can easily understand the speed limitation, and the operability can be improved.

[0245] The main control device 31 may not perform speed limitation through the automatic deceleration control only when the start restriction control state is the forced operation state S4. The main control device 31 may not perform speed limitation through the automatic deceleration control only when the start restriction control state is the forced operation pre-release state S5.

[0246] Alternatively, the main control device 31 may intervene in the automatic deceleration control by assuming that no obstacle exists. If the object detection unit 51 does not detect an obstacle, the state of the driving restriction control is the normal control state S10. If the object detection unit 51 does not detect an obstacle, the states of the speed limit control for people and the speed limit control for obstacles are the restriction release state S21. When performing the automatic deceleration control, the main control device 31 assumes that the object detection unit 51 does not detect an obstacle. Thus, the state of the driving restriction control can be maintained in the normal control state S10, and the states of the speed limit control for people and the speed limit control for obstacles can be maintained in the restriction release state S21. Therefore, the same effects as those of the embodiment can be achieved.

[0247] When the start restriction control state is in the forced operation state S4 or the forced operation pre-release state S5, if a limit value is set by the automatic deceleration control, the main controller 31 may perform control that prioritizes the limit value set by the start restriction control. The main controller 31 may perform speed limiting according to the limit value set by the start restriction control when the start restriction control state is in the forced operation state S4 or the forced operation pre-release state S5, and any method is sufficient.

[0248] The automatic deceleration control may include at least one of the following: driving restriction control, speed restriction control for people, and speed restriction control for obstacles.

[0249] The forced operation pre-release state S5 may be omitted in the start restriction control. In this case, when the main control device 31 is in the forced operation state S4, if the condition F1 is satisfied, the main control device 31 transitions to the normal control state S10.

[0250] In the forced operation state S4, an acceleration upper limit value may be set instead of the vehicle speed upper limit value VS1. In addition, in the forced operation state S4, an acceleration upper limit value may be set in addition to the vehicle speed upper limit value VS1.

[0251] Alternatively, in the forced action pre-release state S5, a vehicle speed upper limit may be set instead of the acceleration upper limit AS1. Alternatively, in the forced action pre-release state S5, a vehicle speed upper limit may be set in addition to the acceleration upper limit AS1. Alternatively, the vehicle speed upper limit set in the forced action pre-release state S5 may be set to a higher value than the vehicle speed upper limit set in the forced action state S4.

[0252] The start restriction control can also be implemented as follows: if an object is present in the start restriction area AA1, the speed is restricted regardless of the estimated trajectory T. For example, this can be achieved by removing condition A2 from the start restriction conditions and removing the conditions related to the estimated trajectory T from the state transition conditions. When the speed is restricted regardless of the estimated trajectory T, the start restriction area AA1 does not need to be divided into multiple areas. Furthermore, the start restriction area AA1 is not limited to the area in the direction of travel of the forklift 10, but can also be an area to the side of the forklift 10. In this case, the stereo camera 52 is positioned so that it can detect objects to the side of the forklift 10.

[0253] The driving restriction control may be a control that restricts the speed regardless of the estimated trajectory T if a person is present in the automatic deceleration area AA2. For example, the driving restriction condition J1 may be modified as follows to remove the condition related to the estimated trajectory T from the state transition condition.

[0254] Condition J1: A person is present in the automatic deceleration area AA2.

[0255] The automatic deceleration area AA2 is not limited to an area in the traveling direction of the forklift 10 , but may be an area on the side of the forklift 10 .

[0256] The obstacle-targeted vehicle speed limit control can also be control in which, if an obstacle is present in the automatic deceleration area AA2, the speed is limited regardless of the predicted trajectory T. For example, it is only necessary to set the vehicle speed limit area in the obstacle-targeted vehicle speed limit control to an area that is not related to the predicted trajectory T. It can also be that the vehicle speed limit area is located further from the forklift 10 than the start limit area AA1 in the automatic deceleration area AA2.

[0257] As described above, in the case where the speed of the forklift 10 is not limited using the predicted trajectory T, the main control device 31 can also not derive the predicted trajectory T.

[0258] It can also be that the higher the lifting height of the load handling device 20, the lower the vehicle speed upper limit value set at the forced action state S4 is set to. In this case, it is not limited to a manner in which the vehicle speed upper limit value is lowered in proportion to an increase in the lifting height of the load handling device 20, as long as the vehicle speed upper limit value is lowered at least at one point when the mast 21 is raised from the lowest position to the highest position, and there is no point at which the vehicle speed upper limit value is raised. For example, a lifting height threshold value is set for the lifting height, and the lifting height is set to a low lifting height if the lifting height is lower than the lifting height threshold value, and the lifting height is set to a high lifting height if the lifting height is equal to or higher than the lifting height threshold value. The main control device 31 sets the vehicle speed upper limit value to be lower in the case where the lifting height is the high lifting height than in the case where the lifting height is the low lifting height.

[0259] Likewise, it can also be that the higher the lifting height of the load handling device 20, the lower the vehicle speed upper limit value set at the limit start state S23 is set to. The vehicle speed upper limit value set at the limit start state S23 is set in accordance with the distance to the object and the lifting height, and is a value that is lower the shorter the distance to the object is, and is a value that is lower the higher the lifting height of the load handling device 20 is. Furthermore, it can also be that one of the vehicle speed upper limit value in the case where a person is present outside the predicted trajectory T and within the automatic deceleration area AA2 and the vehicle speed upper limit value in the case where an obstacle is present within the predicted trajectory T is set to be lower the higher the lifting height of the load handling device 20 is, and it can also be that both are set to be lower the higher the lifting height of the load handling device 20 is. In addition, the vehicle speed upper limit value set at the limit start state S23 can also be a value that varies in accordance with only the lifting height of the load handling device 20, not in accordance with the distance to the object.

[0260] Alternatively, the vehicle speed limit set in the forced operation state S4 may be set to a lower value as the weight of the cargo loaded on the cargo handling device 20 increases. In this case, the vehicle speed limit is not limited to decreasing in proportion to the increase in cargo weight; as long as the vehicle speed limit decreases at at least one point when the cargo weight changes from the unloaded weight to the maximum loaded weight, and there is no point at which the vehicle speed limit increases. For example, a weight threshold may be set for the cargo weight. If the cargo weight is below the weight threshold, the vehicle speed limit is set to light weight, and if the cargo weight is above the weight threshold, the vehicle speed limit is set to heavy weight. When the cargo weight is heavy, the main control device 31 sets the vehicle speed limit lower than when the cargo weight is light.

[0261] Similarly, the speed limit set in restriction start state S23 may be set to a lower value as the weight of the cargo increases. The speed limit set in restriction start state S23 is set based on the distance to the object and the weight of the cargo, with a lower value the shorter the distance to the object and a lower value the heavier the cargo. Alternatively, either the speed limit for when a person is outside predicted trajectory T and within automatic deceleration area AA2 or the speed limit for when an obstacle is within predicted trajectory T may be set to a lower value as the cargo weight increases, or both may be set to lower values ​​as the cargo weight increases. Furthermore, the speed limit set in restriction start state S23 may vary solely based on the cargo weight, not the distance to the object.

[0262] Alternatively, at least one of the vehicle speed upper limit set in the forced operation state S4 and the vehicle speed upper limit set in the restriction start state S23 may be set to a lower value as the lifting height of the cargo handling device 20 increases, and further set to a lower value as the weight of the cargo increases. In other words, the two modified examples described above regarding the vehicle speed upper limit may be combined.

[0263] Alternatively, the acceleration upper limit value set in at least one of the forced action pre-release state S5, the restriction pre-release state S24 when a person is outside the predicted trajectory T, and the restriction pre-release state S24 when an obstacle is outside the predicted trajectory T 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.

[0264] Alternatively, the acceleration upper limit value set in at least one of the forced action pre-release state S5, the restriction pre-release state S24 when a person is outside the predicted trajectory T, and the restriction pre-release state S24 when an obstacle is outside the predicted trajectory T 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 cargo increases.

[0265] Alternatively, the upper limit value of acceleration set in at least one of the forced action pre-release state S5, the restriction pre-release state S24 when a person is outside the predicted trajectory T, and the restriction pre-release state S24 when an obstacle is outside the predicted trajectory T may be set to a value that decreases as the lifting height of the cargo handling device 20 increases, and may also be set to a value that decreases as the weight of the cargo increases. In other words, the two modified examples described above regarding the upper limit value of acceleration may be combined.

[0266] Alternatively, the deceleration upper limit value set in at least one of the travel restriction state S12, the restriction start state S23 when a person is outside the predicted trajectory T, and the restriction start state S23 when an obstacle is within the predicted trajectory T may be set to a lower value as the lift height of the cargo handling device 20 increases. In this case, the forklift 10 decelerates more gradually as the lift height of the cargo handling device 20 increases.

[0267] Alternatively, the deceleration upper limit value set in at least one of the travel restriction state S12, the restriction start state S23 when a person is outside the predicted trajectory T, and the restriction start state S23 when an obstacle is within the predicted trajectory T may be set to a lower value as the weight of the cargo increases. In this case, the forklift 10 decelerates more slowly as the cargo weight increases.

[0268] Alternatively, the deceleration upper limit value set in at least one of the driving restriction state S12, the restriction start state S23 when a person is outside the predicted trajectory T, and the restriction start state S23 when an obstacle is within the predicted trajectory T may be set to a value that decreases as the lift height of the cargo handling device 20 increases, and may also be set to a value that decreases as the weight of the cargo increases. In other words, the two modified examples described above regarding the deceleration upper limit value may be combined.

[0269] When neither the vehicle speed upper limit nor the acceleration upper limit is changed according to the lift height of the cargo handling device 20 , the forklift 10 may not include the lift height sensor 37 .

[0270] If the vehicle speed upper limit, the acceleration upper limit, and the deceleration upper limit are not changed according to the weight of the cargo, the forklift 10 may not include the weight sensor 38 .

[0271] The vehicle speed limit set in the restriction start state S23 does not need to be changed based on the distance to the object. In other words, the vehicle speed limit set in the restriction start state S23 may be a fixed value. In this case, the vehicle speed limit when a person is outside the predicted trajectory T and within the automatic deceleration area AA2 is preferably set to a lower value than the vehicle speed limit when an obstacle is within the predicted trajectory T.

[0272] The main control device 31 may not extend the length of the estimated trajectory T in the traveling direction as the speed of the forklift 10 increases. In this case, the length of the estimated trajectory T in the traveling direction is set to a predetermined constant length.

[0273] The main control device 31 does not need to change the estimated trajectory T according to the steering angle of the steering wheel 14. In other words, the estimated trajectory T may be the estimated trajectory T when the forklift 10 is traveling straight in the reverse direction, regardless of whether the forklift 10 is turning or not.

[0274] Alternatively, the main control device 31 may set the estimated trajectory T to include, in addition to the area 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, an area located outside of the area and extending along the trajectory LT and the trajectory RT. In other words, 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 that the forklift 10 is expected to pass.

[0275] Alternatively, the main control device 31 may derive the predicted trajectory T of the forklift 10 based on the steering angle. For example, a threshold value capable of determining a right turn and a threshold value capable of determining a left turn may be set for the steering angle, allowing the forklift 10 to determine whether it is traveling straight, turning right, or turning left based on the steering angle. When performing start restriction control, the main control device 31 may determine which region N, NL, or NR the forklift 10 is passing through based on the steering angle. In this case, each region N, NL, or NR can be understood as a predicted trajectory.

[0276] The main control device 31 may derive the estimated trajectory T from a map that associates the vehicle speed and steering angle of the forklift 10 with the X-coordinate and the Y-coordinate.

[0277] The main control device 31 may not perform different control depending on whether the object is a person or an obstacle. Specifically, the main control device 31 may stop the forklift 10 when an object is within the predicted trajectory T during automatic deceleration control, and may not impose a speed limit when the object is not within the predicted trajectory T. Furthermore, the main control device 31 may lower the upper speed limit when an object is within the predicted trajectory T compared to when the object is outside the predicted trajectory T during automatic deceleration control. In this case, the obstacle detection device 55 may not determine whether the object is a person.

[0278] The driving restriction control only requires that the main control device 31 be able to 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 met, the main control device 31 transitions to the driving restriction state S12, and when the driving restriction release condition is met, the main control device 31 transitions to the normal control state S10. In other words, the main control device 31 only needs to be able to set the vehicle speed limit to 0 when a person is present within the predicted trajectory T.

[0279] Speed ​​limit control only requires that the main control unit 31 be able to be in at least two states: the restriction release state S21 and the restriction start state S23. In this case, when the first restriction start condition is met, the main control unit 31 transitions to the restriction start state S23, and when the restriction start release condition is met, the main control unit 31 transitions to the restriction release state S21. In other words, the main control unit 31 only needs to be able to set the vehicle speed upper limit when an object is present in the speed limit area.

[0280] The automatic deceleration area AA2 may be an area narrower than the object detectable range of the object detection unit 51 .

[0281] ○ For each state where the acceleration upper limit value or the deceleration upper limit value is not limited, the acceleration upper limit value or the deceleration upper limit value can be set.

[0282] During the state transition in the start restriction control, each condition may be changed as follows.

[0283] The start restriction condition may be satisfied when all of the following conditions A11, A12, and A13 are satisfied.

[0284] Condition A11: An object exists in the start restricted area AA1 and within the predicted trajectory T.

[0285] Condition A12: The forklift 10 is stopped.

[0286] Condition A13: The detection result of the direction sensor 35 is not forward movement.

[0287] Whether condition A11 is satisfied can be determined based on the object's X and Y coordinates. Since the restricted start area AA1 and the predicted trajectory T are defined by the object's X and Y coordinates, it can be determined based on the object's X and Y coordinates whether the object is within the restricted start area AA1 and the predicted trajectory T. Condition A12 is the same as condition A3. Condition A13 indicates whether the direction sensor 35 detects reverse or neutral.

[0288] The start restriction lifting condition may be set as at least one of the following conditions B11 and B12 being satisfied.

[0289] Condition B11: In the start restricted area AA1, there is no object within the predicted trajectory T.

[0290] Condition B12: The detection result of the direction sensor 35 indicates forward movement.

[0291] Condition B11 can also be said to mean that condition A11 does not hold. Condition B12 can also be said to mean that condition A13 does not hold.

[0292] When the start restriction condition and the start restriction release condition are set as described above, the start restriction area AA1 does not need to be divided into the plurality of areas N, NL, and NR.

[0293] The forced action pre-cancellation condition may be satisfied when the condition B11 is satisfied.

[0294] The forced operation formal cancellation condition may be satisfied when any one of the conditions G1 and G2 of the embodiment and the following condition G11 is satisfied.

[0295] Condition G11: The detection result of the direction sensor 35 indicates forward movement.

[0296] By adding condition G11 to the forced action final release condition, if the operator changes the travel direction to the forward direction in the forced action preliminary release state S5, the main control device 31 transitions to the normal control state S10. The operator can intentionally transition the main control device 31 to the normal control state S10 by changing the travel direction to the forward direction.

[0297] The forced action formal cancellation condition may be satisfied when any one of the conditions G1, G2, G11 and the following condition G12 is satisfied.

[0298] Condition G12 ... and the following conditions G21 and G22 both hold true.

[0299] Condition G21: The detection result of the direction sensor 35 indicates that the direction of the area N, NL, or NR where the object is located does not match the direction of the estimated trajectory T and that the area N, NL, or NR is moving backwards, and the direction of the area N, NL, or NR where the object is located does not match the direction of the estimated trajectory T for a predetermined period of time.

[0300] Condition G22: The forklift 10 is traveling.

[0301] If condition G21 is met, it is assumed that the operator of the forklift 10 has changed the turning direction to a direction where no object exists by operating the steering wheel. In other words, it is assumed that the operator of the forklift 10 has recognized the presence of an object through any of the speed limit, acceleration limit, and alarm, and has performed an evasive action to avoid the object. The specified time in condition G21 can be set to any value. The specified time is set to a time that can be determined as a time during which it is determined that the operator of the forklift 10 has performed an evasive action. Even if the turning direction is changed to a direction where no object exists by operating the steering wheel, if the turning direction is returned to a direction where an object exists before the specified time has passed, it is deemed that no evasive action has been performed. The specified time can be set arbitrarily within the range of 1 to 3 seconds, for example.

[0302] Condition G22 is the same as condition E3. The main control device 31 determines that the forklift 10 is traveling when the vehicle speed is higher than the stop determination threshold value [km / h].

[0303] By setting one of the conditions for satisfying condition G12 to condition G21, the forced action pre-release state S5 can be transitioned to the normal control state S10 when the operator performs an evasive maneuver. While the main control device 31 is in the forced action pre-release state S5, the operator may identify an object that would obstruct the forklift 10's movement and perform an evasive maneuver to avoid it. In this case, if acceleration restriction is applied, the acceleration of the forklift 10 will be restricted, preventing the forklift 10 from moving smoothly and potentially reducing operability. By transitioning the main control device 31 to the normal control state S10 when condition G12 is satisfied, the acceleration restriction can be removed. This prevents the forklift 10 from being subject to acceleration restriction during or after an evasive maneuver, thereby preventing a reduction in operability.

[0304] By setting one of the conditions for making the condition G12 true as the condition G22, it is possible to suppress the main control device 31 from immediately transitioning to the start-up restriction state S2 after transitioning to the normal control state S10 due to the condition G12 being true. If it is the case where the conditions for making the condition G12 true are set only as the condition G21, the condition G12 can be true even in a state where the forklift 10 is stopped. In this case, the main control device 31 can sometimes immediately transition to the start-up restriction state S2 after transitioning to the normal control state S10 due to the condition G12 being true. For example, if it is the case where the turning direction is changed to a direction in which there is no object although the forklift 10 is in a stopped state, but the turning direction is then returned to a direction in which there is an object, the main control device 31 can sometimes transition to the start-up restriction state S2. In this case, although the operator wants to perform an avoidance action, the avoidance action can be hindered due to the transition to the start-up restriction state S2. By setting one of the conditions for making the condition G12 true as the condition G22, the condition G12 is true in a case where the forklift 10 is running. In a case where the main control device 31 transitions to the normal control state S10 due to the condition G12 being true, the condition A3 is suppressed from being true, and it is difficult for the start-up restriction condition to be true. Thus, it is possible to suppress the avoidance action from being hindered.

[0305] The condition that the forced action official release condition is true can also be set as any one of the conditions G1, G2, G11, and G21 being true. Even in this case, by the condition G21, it is possible to cause the forced action pre-release state S5 to transition to the normal control state S10 in a case where the operator performs an avoidance action. Thus, it is possible to suppress a decrease in work efficiency. Even if the condition G22 is not true, by causing the main control device 31 to transition to the normal control state S10 in accordance with the condition G21 being true, it is possible to cause the main control device 31 to immediately transition to the start-up restriction state S2 after transitioning to the normal control state S10. In a case where an object approaches the forklift 10, or the like, the conditions A1 and A2 can be true when the main control device 31 transitions from the forced action pre-release state S5 to the normal control state S10. At this time, if it is determined that the forced action official release condition is true due to both the conditions G21 and G22 being true, the condition A3 is suppressed from being true, and sometimes the start-up restriction with respect to a newly detected object does not function. In contrast to this, even if the condition G22 is not true, by causing the main control device 31 to transition to the normal control state S10 in accordance with the condition G21 being true, it is easy for the start-up restriction with respect to a newly detected object to function.

[0306] The condition that the forced action official release condition is true can also be set as any one of the conditions G1, G2, G12, and the following condition G13 being true.

[0307] Condition G13... both of Condition G22 and the following Condition G23 are established.

[0308] Condition G23... the detection result of the direction sensor 35 is a forward traveling state for a prescribed time.

[0309] The prescribed time in Condition G23 is the same time as the prescribed time in Condition G21. By establishing the forced action formal release condition in the case where either of Condition G12 and Condition G13 is established, the main control device 31 can be shifted to the normal control state S10 by the same operation regardless of whether the traveling direction of the forklift 10 is the forward direction or the backward direction. In detail, in the case where the forward-direction avoidance action is continued for a prescribed time and in the case where the backward-direction avoidance action is continued for a prescribed time, the main control device 31 is shifted to the normal control state S10. In order to shift the main control device 31 to the normal control state S10, the operator only needs to perform the same operation regardless of whether the traveling direction of the forklift 10 is the forward direction or the backward direction, and improvement in operability can be achieved.

[0310] The forced action formal release condition can also be established as establishment of any one of Condition G1, G2, G21, and G23. In this case, even if Condition G22 is not established, the main control device 31 can be shifted to the normal control state S10 in accordance with establishment of any one of Condition G21 and Condition G23. Thus, the start-up restriction with respect to a newly detected object easily functions. In addition, in order to shift the main control device 31 to the normal control state S10, the operator only needs to perform the same operation regardless of whether the traveling direction of the forklift 10 is the forward direction or the backward direction, and improvement in operability can be achieved.

[0311] The forced action formal release condition can also be established as establishment of any one of Condition G1, G2, and G12. It can also be established as establishment of any one of Condition G1, G2, and G21.

[0312] The forced action formal release condition can also be established as establishment of any one of Condition G1, G2, G11, G12, and G13. In this case, in the case where Condition G13 is established, Condition G11 is established, and Condition G13 becomes a condition that substantially does not function. Thus, the same effect as in the case where the forced action formal release condition is established as establishment of any one of Condition G1, G2, G11, and G12 can be obtained.

[0313] The forced action condition can be any condition, as long as it can be determined that the operator has recognized the presence of an object in the restricted start area AA1. For example, the forced action condition can be a steering wheel operation performed by the operator. Whether the steering wheel has been operated can be determined based on the detection results of the steering wheel angle sensor or the tire angle sensor 36 that detects the steering wheel angle. Alternatively, the forced action release condition can be, for example, a button operation performed by the operator, voice input via the input unit, or operation of a touch panel included in the forklift 10.

[0314] In the start restriction state S2 , the warning device 58 does not necessarily need to warn the operator.

[0315] In the start prohibition state S3, the warning of the warning device 58 does not need to be amplified, and the same warning as in the start restriction state S2 may be issued. In addition, in the start prohibition state S3, the warning by the warning device 58 does not need to be issued.

[0316] In the forced operation state S4, the warning of the warning device 58 does not need to be weakened compared to the start prohibition state S3, and the same warning as that in the start prohibition state S3 may be issued.

[0317] In the travel restriction control, the pre-travel restriction state S11 may be omitted. In this case, the warning area may not be set.

[0318] The alarm in the pre-travel restriction state S11 and the pre-restriction start state S22 may also be issued when the forklift 10 turns around.

[0319] In the restricted driving state S12 , the warning device 58 may not issue a warning.

[0320] The pre-limit start state S22 may be omitted in at least one of the speed limit control for people and the speed limit control for obstacles. In this case, the pre-warning area may not be set.

[0321] The alarm device 58 may not be used to issue an alarm in all states of the start restriction control, the travel restriction control, the speed restriction control for people, and the speed restriction control for obstacles. In this case, the forklift 10 may not be equipped with the alarm device 58.

[0322] The restricted start area AA1 may be divided into four or more areas.

[0323] The left-right dimension of the central region N may be slightly longer or shorter than the vehicle width dimension of the forklift 10 .

[0324] The steering angle of the steering wheel 14 can also be determined using the detection results of a steering wheel angle sensor. The steering wheel angle sensor detects the angle of the steering wheel and outputs the detection results to the main control unit 31. The steering angle is controlled based on the detection results of the steering wheel angle sensor. Therefore, the steering angle can be detected based on the detection results of the steering wheel angle sensor.

[0325] The object detection unit 51 only needs to be able to detect objects around the forklift 10. For example, the object detection unit 51 may detect the position of an object in the forward direction of the forklift 10. In this case, the stereo camera 52 is positioned facing forward of the forklift 10. When the object detection unit 51 detects the position of an object in the forward direction of the forklift 10, the automatic deceleration area AA2 and the start restriction area AA1 become areas extending forward from the forklift 10. Furthermore, when the forklift 10 is moving forward, the start restriction control, the travel restriction control, the speed limit control for people, and the speed limit control for obstacles function. Specifically, by reversing the "rear" and "front" designations described in the embodiment for each of the start restriction control, the travel restriction control, the speed limit control for people, and the speed limit control for obstacles, the speed limit can be applied based on the position of an object when the forklift 10 is moving forward. When the object detection unit 51 detects the position of an object existing in the forward direction of the forklift 10 , the main control device 31 derives an estimated trajectory T extending in the forward direction.

[0326] The object detection unit 51 may be one that can detect the position of an object in either the forward or backward direction of the forklift 10. In this case, a single object detection unit 51 may be configured to detect objects in both the forward and backward directions of the forklift 10, or a forward and backward object detection unit 51 may be provided. When detecting the position of objects in both the forward and backward directions of the forklift 10, when the forklift 10 is moving forward, a speed limit is applied due to an object in the forward direction. When the forklift 10 is moving backward, a speed limit is applied due to an object in the backward direction. In other words, the main control unit 31 sets the upper speed limit when the forklift 10 is moving in a direction approaching an object detected by the object detection unit 51.

[0327] Furthermore, when the speed limit is applied regardless of whether the forklift 10 is moving forward or backward, the forced operation formal release condition is preferably satisfied when any one of the conditions G1, G2, G12, and G13 is satisfied.

[0328] Condition G23: The detection result of the direction sensor 35 indicates that the vehicle is moving forward and the area where the object is located does not match the direction of the expected trajectory for a predetermined time.

[0329] In other words, the main control device 31 determines whether the state in which the predicted trajectory extending forward of the forklift 10 does not coincide with the area in front of the forklift 10 where the object exists continues for a predetermined time.

[0330] The object detection unit 51 may also use a ToF (Time of Flight) camera, LIDAR (Laser Imaging Detection and Ranging), millimeter-wave radar, or the like in place of the stereo camera 52. A ToF camera includes a camera and a light source for emitting light. Based on the time it takes to receive reflected light from the light source, the depth distance is derived for each pixel in the image captured by the camera. LIDAR is a distance meter that can identify the surrounding environment by emitting laser light while changing the irradiation angle and receiving light reflected from the portion illuminated by the laser. Millimeter-wave radar is a radar that can identify the surrounding environment by emitting radio waves in a predetermined frequency band. The stereo camera 52, ToF camera, LIDAR, and millimeter-wave radar are sensors capable of measuring three-dimensional coordinates within a world coordinate system. It is preferable that the object detection unit 51 include a sensor capable of measuring three-dimensional coordinates. If the object detection unit 51 includes a sensor capable of measuring three-dimensional coordinates, the obstacle detection device 55 can determine whether an object is a person or an obstacle by using a person determination unit that has undergone pre-machine learning. Furthermore, the object detection unit 51 may include a combination of the stereo camera 52 and a plurality of sensors such as LIDAR.

[0331] Alternatively, the object detection unit 51 may include a sensor capable of measuring the coordinates of an object within the XY plane, which is a coordinate plane representing a horizontal plane, in place of the stereo camera 52. Specifically, a sensor capable of measuring the two-dimensional coordinates of an object may be used. For example, a two-dimensional LIDAR sensor that irradiates laser light while changing the horizontal irradiation angle may be used as such a sensor.

[0332] The stereo camera 52 may include three or more cameras.

[0333] The obstacle detection device 55 may also use a comparison image in the images captured by the stereo camera 52 to determine whether an object is a person or an obstacle. The object's coordinates are derived from the reference image. Therefore, deriving the coordinates of the object in the comparison image from the object's coordinates will result in a deviation corresponding to the baseline length. Therefore, the obstacle detection device 55 corrects the coordinates of the object in the comparison image based on the baseline length and performs human detection processing on the corrected coordinates.

[0334] ○ A portion other than the object detection unit 51 may include the alarm device 58 .

[0335] The main control device 31 may directly activate the alarm device 58 .

[0336] The forklift 10 may be a forklift that travels by being driven by an engine as a driving device. In this case, the travel control device 43 serves as a device that controls the amount of fuel injected into the engine, etc.

[0337] The forklift 10 may also be a four-wheel forklift 10. In this case, the main control device 31 derives the expected trajectory T based on the formula or map that derives the expected trajectory T of the four-wheel forklift 10. That is, the formula or map that derives the expected trajectory T changes depending on the type of industrial vehicle.

[0338] The forklift 10 may be a forklift capable of switching between automatic operation and manual operation.

[0339] The forklift 10 may be remotely operated by an operator who is not riding the forklift 10 .

[0340] The forklift 10 may be a forklift in which the two drive wheels 12 and 13 are rotated by one travel motor.

[0341] The device for performing start restriction control and the device for performing automatic deceleration control may be provided separately. In this case, the device for performing start restriction control is the first control unit, and the device for performing automatic deceleration control is the second control unit. Furthermore, the predicted trajectory derivation unit may be provided separately from the device for performing start restriction control or automatic deceleration control.

[0342] The main control device 31 , the travel control device 43 , and the object detection unit 51 may be configured to be able to acquire information from each other via wireless devices.

[0343] Industrial vehicles can be any type of vehicle, as long as they are used to operate within a limited area, such as a tractor truck used to transport cargo, a picker used for picking goods, etc. In other words, industrial vehicles can also be vehicles that do not have a cargo handling device 20 for loading or unloading cargo.

[0344] Description of Reference Numerals

[0345] 10…Forklifts as Industrial Vehicles

[0346] 31 ... as a main control device for the first control unit, the second control unit, the speed limit unit, the start prohibition control unit, the start permission control unit, the first permission control unit, the second permission control unit, and the estimated trajectory derivation unit

[0347] 41…Travel motor as a drive device

[0348] 43…Travel control device

[0349] 51…Object detection unit.

Claims

1. An industrial vehicle comprising: drive mechanism; and an accelerator pedal and an acceleration sensor for detecting an accelerator opening of the accelerator pedal, a travel control device that controls the drive device, The industrial vehicle is characterized by comprising: an object detecting unit that detects a position of an object existing around the industrial vehicle; a first control unit configured to set a limit value for performing speed limitation including at least one of a speed limit and an acceleration limit on the industrial vehicle when the speed of the industrial vehicle is within a first speed range; a second control unit configured to set the limit value when the speed of the industrial vehicle is within a second speed range; as well as a speed limiting unit that performs the speed limitation according to the limit value selected from the limit value set by the first control unit and the limit value set by the second control unit, The lower limit value of the second vehicle speed range is a value higher than the lower limit value of the first vehicle speed range. The first control unit includes: a start prohibition control unit configured to set the limit value in a start prohibition state so that travel of the industrial vehicle is prohibited when the object is detected by the object detection unit; as well as a start permission control unit that sets the limit value in the forced operation state so that travel of the industrial vehicle is permitted, when it is determined that the operator of the industrial vehicle has recognized the presence of the object based on detection that the operator of the industrial vehicle has released the accelerator pedal after transitioning to the start prohibited state; The speed limiting unit performs the speed limitation according to the limit value set by the first control unit when the limit value is set by the start permission control unit.

2. The industrial vehicle according to claim 1, wherein: have: alarm devices; as well as an estimated trajectory deriving unit that derives an estimated trajectory as a trajectory that the industrial vehicle is expected to pass through, The start permission control unit includes: a first permission control unit configured to set the limit value and issue an alarm through the alarm device; as well as a second permission control unit that sets the limit value and does not issue an alarm through the alarm device; The speed limiting unit performs the speed limitation according to the limit value set by the first control unit when the limit value is set by the second permission control unit and the object does not exist within the estimated trajectory derived by the estimated trajectory deriving unit.

3. An industrial vehicle according to claim 1 or claim 2, wherein: The speed limiting unit performs the speed limiting according to the limit value set by the first control unit, in either case when the limit value is set by the start prohibition control unit or when the limit value is set by the start permission control unit.

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