Industrial vehicle obstacle notification device and industrial vehicle

Abstract

To notify an operator of an industrial vehicle of the existence of an obstacle which causes at least one of restriction of travel of the industrial vehicle and warning.SOLUTION: An obstacle notification device for an industrial vehicle comprises: an obstacle detection unit; a display unit; and a control device. The obstacle detection unit detects the positional relations between the industrial vehicle and obstacles. The control device displays a first image on the display unit when an obstacle different from a causal obstacle is notified of. The control device displays a second image different from the first image on the display unit when the causal obstacle is notified of. The causal obstacle coincides with a specific condition among the obstacles. The causal obstacle causes at least one of restriction of travel of the industrial vehicle and warning.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to an obstacle notification device for an industrial vehicle and an industrial vehicle. [Background technology]

[0002] The obstacle detection device disclosed in Patent Document 1 detects obstacles using a camera installed in a vehicle. When the obstacle detection device detects an obstacle, it notifies the vehicle operator of the type and location of the obstacle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-254710 Summary of the Invention [Problem to be solved by the invention]

[0004] In an industrial vehicle, when an obstacle that meets a specific condition is present, at least one of restricting the travel of the industrial vehicle and issuing an alarm may be performed. In an industrial vehicle, it is required to notify an operator of the industrial vehicle whether an obstacle that is causing at least one of restricting the travel of the industrial vehicle and issuing an alarm is present. [Means for solving the problem]

[0005] The obstacle notification device for an industrial vehicle that solves the above problem comprises an obstacle detection unit that detects the positional relationship between the industrial vehicle and an obstacle, a display unit, and a control unit, and at least one of restricting the progress of the industrial vehicle and issuing an alarm when a causal obstacle among the obstacles meets specific conditions, and when the control unit notifies of an obstacle different from the causal obstacle, it displays a first image on the display unit, and when notifying of the causal obstacle, it displays a second image different from the first image on the display unit.

[0006] The control device displays the first image on the display unit when notifying an obstacle different from the causative obstacle. The control device displays the second image on the display unit when notifying the causative obstacle. This allows the control device to notify the operator of the industrial vehicle of the presence of the causative obstacle.

[0007] In the obstacle notification device for the above-mentioned industrial vehicle, the industrial vehicle may restrict the progress of the industrial vehicle when the industrial vehicle starts moving due to the causative obstacle, and the control device may display the second image on the display unit if the progress of the industrial vehicle is restricted when the industrial vehicle starts moving.

[0008] In the obstacle notification device for the industrial vehicle, the control device may display the second image on the display unit when the industrial vehicle is stopped. In the obstacle notification device for the above-mentioned industrial vehicle, the display unit includes an icon that resembles the industrial vehicle, a rear right display area that indicates the area behind and to the right of the icon, a rear left display area that indicates the area behind and to the left of the icon, and a rear center display area between the rear right display area and the rear left display area, and the control device may display the second image in at least one of the rear right display area, the rear left display area, and the rear center display area based on the positional relationship between the industrial vehicle and the causative obstacle.

[0009] An industrial vehicle that solves the above problem comprises an obstacle notification device for the industrial vehicle, a steering wheel, and a tire angle sensor that detects the steering angle of the steering wheel, and the control device determines the planned travel area of ​​the industrial vehicle from the tire angle sensor, and if the planned travel area coincides with one of multiple restricted areas set in the direction of travel of the industrial vehicle in which the causative obstacle exists, it restricts the travel of the industrial vehicle and displays the second image on the display unit.

[0010] The control device can notify the operator of the industrial vehicle of the presence of a culprit obstacle. [Effects of the Invention]

[0011] According to the present invention, it is possible to notify an operator of an industrial vehicle of the presence of an obstacle that causes at least one of a restriction on the travel of the industrial vehicle and an alarm. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view of a forklift. [Figure 2] FIG. 1 is a schematic diagram of a forklift. [Figure 3] 10 is a flowchart showing obstacle detection control. [Figure 4] FIG. 2 is a diagram schematically illustrating a departure restriction area. [Figure 5] FIG. 4 is a state transition diagram of the start restriction control. [Figure 6] 10 is a flowchart showing display control. [Figure 7] FIG. 10 is a diagram illustrating an example of a notification screen displayed on a display unit. DETAILED DESCRIPTION OF THE INVENTION

[0013] An embodiment of an obstacle notification device for an industrial vehicle and an industrial vehicle will be described below. <Forklift> As shown in FIG. 1, a forklift 10 as an industrial vehicle includes a body 11, two drive wheels 12, 13 arranged at the front of the body 11, two steering wheels 14 arranged at the rear of the body 11, and a cargo handling device 20. The two drive wheels 12, 13 are arranged spaced apart 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 in a central position between the drive wheels 12, 13 in the vehicle width direction. If the two adjacent steering wheels 14 are considered to be one steering wheel 14, the forklift 10 can be considered a three-wheeled forklift. The body 11 includes a head guard 15 provided above the driver's seat. In the following description, front, rear, left, and right refer to the front, rear, left, and right of the forklift 10.

[0014] The cargo handling device 20 includes a mast 21, two forks 22, and a lift cylinder 23. The mast 21 is provided at the front of the vehicle body 11. The forks 22 are provided so that they can be raised and lowered together with the mast 21. A load is placed on the forks 22. The lift cylinder 23 is a hydraulic cylinder. The mast 21 is raised and lowered by the extension and contraction of the lift cylinder 23. As the mast 21 is raised and lowered, the forks 22 are raised and lowered. The forklift 10 of this embodiment is operated by an operator to perform traveling operations and cargo handling operations.

[0015] 2, the forklift 10 includes an accelerator pedal 16, a direction lever 17, a parking brake operating member 18, an accelerator sensor 34, a direction sensor 35, a tire angle sensor 36, a parking switch 37, a parking brake 38, a travel motor 41, a rotation speed sensor 42, a travel control device 43, and an industrial vehicle obstacle notification device 70. The industrial vehicle obstacle notification device 70 includes a control device 31, an obstacle detection unit 51, and a display unit 71.

[0016] The control device 31 includes a processor 32 and a storage unit 33. The processor 32 may be, for example, a central processing unit (CPU), a graphics processing unit (GPU), or a digital signal processor (DSP). The storage unit 33 includes a random access memory (RAM) and a read-only memory (ROM). A program for operating the forklift 10 is stored in the storage unit 33. The storage unit 33 can be said to store program code or instructions configured to cause the processor 32 to execute processing. The storage unit 33, i.e., a computer-readable medium, includes any available medium accessible by a general-purpose or dedicated computer. The control device 31 may be configured with hardware circuits such as an application-specific integrated circuit (ASIC) or a field-programmable gate array (FPGA). The control device 31, which is a processing circuit, may include one or more processors operating according to a computer program, one or more hardware circuits such as an ASIC or an FPGA, or a combination thereof.

[0017] The accelerator sensor 34 detects the amount of operation of the accelerator pedal 16, i.e., the accelerator opening degree. The accelerator sensor 34 outputs an electric signal corresponding to the accelerator opening degree to the control device 31. The control device 31 can recognize the accelerator opening degree from the electric signal from the accelerator sensor 34.

[0018] The direction sensor 35 detects the operating direction of the direction lever 17, which indicates the direction of travel. The direction sensor 35 detects whether the direction lever 17 is operated in a direction instructing forward movement or in a direction instructing reverse movement, with the neutral position as the reference position. The direction sensor 35 outputs an electric signal according to the operating direction of the direction lever 17 to the control device 31. The control device 31 can recognize the operating direction of the direction lever 17 from the electric signal from the direction sensor 35. The control device 31 can recognize whether the operator is instructing forward movement, reverse movement, or neither.

[0019] The tire angle sensor 36 detects the steering angle of the steered wheels 14. The tire angle sensor 36 outputs an electrical signal corresponding to the steering angle to the control device 31. The control device 31 can recognize the steering angle from the electrical signal from the tire angle sensor 36.

[0020] The parking brake 38 is switched between actuation and deactuation by the parking brake operation member 18. The parking brake 38 may be of a mechanical type or an electric type. The mechanical type is a system in which the parking brake 38 and the parking brake operation member 18 are connected by a wire to actuate the parking brake 38 directly. The electric type is a system in which the parking brake 38 is actuated electrically by operating the parking brake operation member 18.

[0021] The parking switch 37 detects whether the parking brake 38 is applied. The parking switch 37 is turned on when the parking brake 38 is applied by the parking brake operating member 18. The parking switch 37 is turned off when the parking brake 38 is deactivated by the parking brake operating member 18.

[0022] The travel motor 41 is a drive device for propelling the forklift 10. The drive motor 41 drives the drive wheels 12, 13 to rotate, thereby propelling the forklift 10. A travel motor 41 is provided for each of the drive wheels 12, 13.

[0023] The rotation speed sensor 42 detects the rotation speed of the traveling motor 41. For example, a rotary encoder can be used as the rotation speed sensor 42. The rotation speed sensor 42 outputs an electric signal corresponding to the rotation speed of the traveling motor 41 to the traveling control device 43.

[0024] The travel control device 43 is a motor driver that controls the rotation speed of the travel motor 41. The travel control device 43 can recognize the rotation speed and rotation direction of the travel motor 41 from the electrical signal of the rotation speed sensor 42. The rotation direction of the travel motor 41 is represented by a ± sign. A positive rotation speed indicates forward rotation, and a negative sign indicates reverse rotation.

[0025] The obstacle detection unit 51 detects the position of an obstacle. The obstacle detection unit 51 includes a stereo camera 52, a detection device 53, and an alarm unit 58. The stereo camera 52 includes two cameras and captures images using the two cameras. As shown in FIG. 1 , the stereo camera 52 is disposed on the head guard 15. The stereo camera 52 is disposed so as to provide a bird's-eye view of the road surface on which the forklift 10 is traveling from above the forklift 10. In this embodiment, the stereo camera 52 captures images behind the forklift 10. Therefore, an obstacle detected by the obstacle detection unit 51 is an obstacle behind the forklift 10. The detection direction of the obstacle detection unit 51 can be said to be rearward. The alarm unit 58 and the detection device 53 may be united with the stereo camera 52 and disposed on the head guard 15 together with the stereo camera 52. The alarm unit 58 and the detection device 53 may also be disposed in positions different from the head guard 15.

[0026] The detection device 53 includes a processor 54 and a storage unit 55. The processor 54 may be, for example, a CPU, a GPU, or a DSP. The storage unit 55 includes RAM and ROM. The storage unit 55 stores various programs for detecting obstacles from images captured by the stereo camera 52. The storage unit 55 stores program code or instructions configured to cause the processor 54 to execute processing. The storage unit 55, i.e., a computer-readable medium, includes any available medium accessible by a general-purpose or special-purpose computer. The detection device 53 may be configured by a hardware circuit such as an ASIC or FPGA. The detection device 53, which is a processing circuit, may include one or more processors operating according to a computer program, one or more hardware circuits such as an ASIC or FPGA, or a combination thereof.

[0027] The detection device 53 detects obstacles present behind the forklift 10 by repeatedly performing the following obstacle detection control at a predetermined control cycle. The detection device 53 also derives the position of the detected obstacle. The position of the obstacle is the relative position between the forklift 10 and the obstacle. It can be said that the obstacle detection unit 51 detects the positional relationship between the forklift 10 and the obstacle.

[0028] As shown in FIG. 3, in step S100, the detection device 53 acquires an image from the stereo camera 52. Next, in step S110, the detection device 53 performs stereo processing to acquire a parallax image. A parallax image is one in which a parallax [px] is associated with each pixel. A parallax image does not necessarily need to be displayed, but refers to data in which a parallax is associated with each pixel in the parallax image. The parallax is obtained by comparing two images captured by the stereo camera 52 and deriving the difference in the number of pixels between the images for the same feature point appearing in each image. A feature point is a part that can be recognized as a boundary, such as the edge of an obstacle. A feature point can be detected from brightness information, etc.

[0029] Next, in step S120, the detection device 53 derives the coordinates of the feature points in a world coordinate system, which is a coordinate system in real space. The world coordinate system is a coordinate system in which, when the forklift 10 is positioned on a horizontal plane, the axis extending in the vehicle width direction of the forklift 10 is the X-axis, the axis perpendicular to the X-axis is the Y-axis, and the axis extending in the vertical direction is the Z-axis. The coordinates of the feature points are derived by deriving the coordinates of the feature points in the camera coordinate system from the base length of the stereo camera 52, the focal length of the stereo camera 52, and the parallax image obtained in step S110, and then converting the coordinates into coordinates in the world coordinate system. As shown in FIG. 1, the X-axis, Y-axis, and Z-axis are indicated by arrows X, Y, and Z.

[0030] Next, in step S130, the detection device 53 extracts obstacles by clustering the feature points. The detection device 53 groups together a set of feature points that are points that represent parts of obstacles and that are assumed to represent the same obstacle into a single point cloud, and extracts the point cloud as an obstacle. The detection device 53 performs clustering by regarding feature points located within a predetermined range from the coordinates of the feature points in the world coordinate system derived in step S120 as a single point cloud. The detection device 53 regards the clustered point cloud as a single obstacle. Note that the clustering of feature points performed in step S130 can be performed using various methods.

[0031] Next, in step S140, the detection device 53 derives the coordinates of the obstacle in the world coordinate system. The coordinates of the obstacle can be derived from the coordinates of the feature points that make up the point cloud. The coordinates of the obstacle in the world coordinate system represent the relative position between the forklift 10 and the obstacle. Specifically, the X coordinate of the obstacle's coordinates in the world coordinate system represents the left-right distance from the origin to the obstacle, and the Y coordinate represents the front-rear distance from the origin to the obstacle. The origin is, for example, a coordinate system in which the X and Y coordinates represent the position of the stereo camera 52 and the Z coordinate represents the road surface. It is also possible to derive the Euclidean distance from the position of the stereo camera 52 to the obstacle from the X and Y coordinates. The Z coordinate of the obstacle's coordinates in the world coordinate system represents the height of the obstacle from the road surface. After completing the processing of step S140, the detection device 53 terminates the obstacle detection control.

[0032] The alarm unit 58 is a device that issues an alarm to the operator of the forklift 10. The alarm unit 58 includes a buzzer 59 that issues an alarm by sound, and a lamp 60 that issues an alarm by light. The display unit 71 is provided in a position visible to the operator of the forklift 10. The display unit 71 displays various information related to the forklift 10.

[0033] <Control performed by the control device> The control device 31, the driving control device 43, and the obstacle detection unit 51 are configured to be able to acquire information from one another. The control device 31, the driving control device 43, and the obstacle detection unit 51 acquire information from one another by communicating in accordance with a vehicle communication protocol such as CAN (Controller Area Network) or LIN (Local Interconnect Network).

[0034] The control device 31 derives the vehicle speed [km / h] of the forklift 10. The vehicle speed of the forklift 10 can be derived using the rotation speed and rotation direction of each of the travel motors 41 provided for the drive wheels 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 the like. The rotation speed and rotation direction of the travel motor 41 can be acquired from the travel control device 43. The gear ratio and the outer diameter of the drive wheels 12 may be stored in advance in the memory unit 33. The control device 31 derives the traveling direction of the forklift 10 as well as the vehicle speed of the forklift 10. The traveling direction of the forklift 10 is either the forward direction or the reverse direction.

[0035] The control device 31 activates the alarm unit 58 by transmitting an alarm command to the obstacle detection unit 51. In detail, the obstacle detection unit 51 includes an activation unit that activates the alarm unit 58, and upon receiving the alarm command, the activation unit activates the alarm unit 58.

[0036] <Departure Restriction Area> The control device 31 performs start limit control. The start limit control is a control that limits the start of the forklift 10 in accordance with the position of an obstacle detected by the obstacle detection unit 51. First, a start limit area used in the start limit control will be described.

[0037] As shown in Fig. 4, a start restriction area AA1 used for start restriction control is set within the range in which the obstacle detection unit 51 can detect an obstacle. The range in which the obstacle detection unit 51 can detect an obstacle can also be said to be the range in which the stereo camera 52 can capture an image. The start restriction area AA1 is an area that extends from the position in which the stereo camera 52 is disposed to the rear of the forklift 10 and in the vehicle width direction of the forklift 10. The start restriction area AA1 is an area defined by X coordinates and Y coordinates in a world coordinate system. In the following description, the X coordinates and Y coordinates are coordinates in the world coordinate system.

[0038] The departure restriction area AA1 is divided into three areas: a central restriction area N, a left restriction area NL located to the left of the central restriction area N, and a right restriction area NR located to the right of the central restriction area N. The central restriction area N is an area facing the forklift 10 in the longitudinal direction. The left-right dimension of the central restriction area N matches the widthwise dimension of the forklift 10. The central restriction area N can also be said to be an area through which the forklift 10 passes when traveling straight backward. The left restriction area NL can also be said to be an area through which the forklift 10 passes when turning left while traveling backward. The right restriction area NR can also be said to be an area through which the forklift 10 passes when turning right while traveling backward. The longitudinal dimension and the left-right dimension of the departure restriction area AA1 can be freely adjusted. The central restriction area N, left restriction area NL, and right restriction area NR are multiple restriction areas set in the traveling direction of the forklift 10.

[0039] <Start Limit Control> 5, in the start restriction control, the control device 31 transitions to one of a normal control state S10, a start restriction state S20, a start prohibition state S30, and a forced operation state S40. The control device 31 performs control according to each of the states S10 to S40.

[0040] The normal control state S10 is a state in which no vehicle speed limit is imposed. When the control device 31 is in the normal control state S10, the control device 31 calculates a target vehicle speed from the accelerator opening detected by the accelerator sensor 34. The control device 31 calculates a target rotation speed from the target vehicle speed. The target rotation speed is the rotation speed required for the forklift 10 to reach the target vehicle speed. The control device 31 also determines whether the forklift 10 should move forward or backward based on the operating direction of the direction lever 17. The control device 31 generates a command including information indicating the target rotation speed and information indicating the rotation direction of the travel motor 41, and issues the command to the travel control device 43. The travel control device 43 controls the travel motor 41 to follow the target rotation speed set by the command. The travel control device 43 controls the travel motor 41 so that the travel motor 41 rotates in the rotation direction set by the command. As a result, in the normal control state S10, the forklift 10 travels at a vehicle speed that corresponds to the amount of operation of the accelerator pedal 16 by the operator.

[0041] The start restriction state S20 is a state in which the forklift 10 is restricted from starting from a stopped state by setting the upper vehicle speed limit [km / h] to 0. Starting refers to transitioning the forklift 10 from a stopped state to a traveling state. Restrictions on starting include prohibiting starting and starting the forklift 10 when an upper vehicle speed limit has been set. When an upper vehicle speed limit has been set, the control device 31 controls the forklift 10 so that its speed does not exceed the upper vehicle speed limit. For example, when the target vehicle speed calculated from the accelerator position is less than the upper vehicle speed limit, the control device 31 calculates the target rotation speed from the target vehicle speed calculated from the accelerator position. When the target vehicle speed calculated from the accelerator position is equal to or greater than the upper vehicle speed limit, the control device 31 calculates the target rotation speed using the upper vehicle speed limit instead of the target vehicle speed. The control device 31 then issues a command to the travel control device 43 so that the target rotation speed and the rotation speed of the travel motor 41 match. When the vehicle speed upper limit value is 0, it can be said that the forklift 10 is prohibited from traveling. In the start restriction state S20, the warning unit 58 issues a warning.

[0042] The start prohibition state S30 is a state in which the upper vehicle speed limit value is set to 0, thereby prohibiting the forklift 10 from starting. In the start prohibition state S30, the alarm by the alarm unit 58 is made stronger than in the start restriction state S20. Increasing the alarm strength means, for example, increasing the volume of the buzzer 59 or shortening the interval at which the buzzer 59 sounds. The alarm strength may also be increased by switching from an alarm by either the buzzer 59 or the lamp 60 to an alarm by both.

[0043] The forced operation state S40 is a state in which a vehicle speed upper limit is set to impose a vehicle speed limit on the forklift 10. The vehicle speed upper limit set in the forced operation state S40 is a value greater than 0 and lower than the maximum vehicle speed that the forklift 10 can reach. For example, the vehicle speed upper limit set in the forced operation state S40 is set to a vehicle speed that is permitted when the forklift 10 is retreating. In the forced operation state S40, the alarm unit 58 issues an alarm. In the forced operation state S40, the alarm issued by the alarm unit 58 may be weaker than in the start prohibition state S30.

[0044] When the control device 31 is in the normal control state S10 and the start restriction condition is satisfied, the control device 31 transitions to the start restriction state S20. The start restriction condition is satisfied when all of the first restriction condition, the second restriction condition, and the third restriction condition are satisfied.

[0045] First restriction condition: Forklift 10 is stopped. Second restriction condition: An obstacle exists in the departure restriction area AA1. Third restriction condition: The parking brake 38 is not activated.

[0046] Whether or not the first restriction condition is met can be determined from the vehicle speed derived by the control device 31. The control device 31 determines that the forklift 10 is stopped when the vehicle speed is equal to or less than a stop determination threshold [km / h]. The stop determination threshold is set to a value at which the forklift 10 is considered to be stopped. The stop determination threshold can be set to any value between 0 [km / h] and 0.5 [km / h], for example.

[0047] Whether the second restriction condition is met can be determined from the X and Y coordinates of the obstacle. Because the departure restriction area AA1 is defined by the X and Y coordinates, it can be determined from the X and Y coordinates of the obstacle whether the obstacle is present in the departure restriction area AA1.

[0048] Whether or not the third restriction condition is met can be determined from the detection result of the parking switch 37. The third restriction condition may be omitted. When the control device 31 is in the start restriction state S20 and the start restriction release condition is met, the control device 31 transitions to the normal control state S10. When at least one of the first restriction condition, the second restriction condition, and the third restriction condition is no longer met, the start restriction release condition is met. The expression "at least one" used in this specification means "one or more" of the desired options. As an example, the expression "at least one" used in this specification means "only one option" or "both of two options" if the number of options is two. As another example, the expression "at least one" used in this specification means "only one option" or "any combination of two or more options" if the number of options is three or more.

[0049] If the start prohibition condition is satisfied when the control device 31 is in the start restriction state S20, the control device 31 transitions to the start prohibition state S30. The start prohibition condition is satisfied when all of the first prohibition condition, second prohibition condition, third prohibition condition, and fourth prohibition condition are satisfied.

[0050] First prohibited condition: Forklift 10 is stopped. Second prohibition condition: An obstacle exists in the area where the forklift 10 is scheduled to travel. Third prohibition condition: The detection result of the direction sensor 35 is reverse.

[0051] Fourth prohibited condition: Accelerator on. Whether the second prohibition condition is met can be determined from the detection result of the tire angle sensor 36 and the X and Y coordinates of the obstacle. The expected travel area of ​​the forklift 10 is the area among the center restricted area N, the left restricted area NL, and the right restricted area NR into which the forklift 10 is expected to travel. The control device 31 determines the expected travel area from the tire angle sensor 36. A left turn is determined when the angle of the steering wheels 14 detected by the tire angle sensor 36 is equal to or greater than a predetermined angle in the left turn direction. A right turn is determined when the angle of the steering wheels 14 detected by the tire angle sensor 36 is equal to or greater than a predetermined angle in the right turn direction. The predetermined angle used to determine left and right turns can be set arbitrarily within the range of 4° to 6°, for example. A straight drive is determined when the angle of the steering wheels 14 detected by the tire angle sensor 36 is less than the predetermined angle. The expected travel area for straight drive is the center restricted area N. The expected travel area for left turns is the left restricted area NL and the center restricted area N. When turning right, the planned travel area is the right restricted area NR and the center restricted area N. The control device 31 determines that the second prohibition condition is met when the restricted area N, NL, NR in which an obstacle exists matches the planned travel area. When one obstacle is located across multiple restricted areas N, NL, NR, or when multiple obstacles are located in different restricted areas N, NL, NR, the control device 31 determines that an obstacle exists in each restricted area N, NL, NR. In this case, the control device 31 determines that the second prohibition condition is met when the planned travel area matches any of the restricted areas N, NL, NR in which an obstacle exists.

[0052] The fourth prohibition condition can be determined from the detection result of the accelerator sensor 34. "Accelerator on" means that the accelerator pedal 16 is being operated by the operator of the forklift 10.

[0053] If the forced operation condition is met when the control device 31 is in the start prohibition state S30, the control device 31 transitions to the forced operation state S40. Mandatory operating condition: accelerator off.

[0054] Whether or not the forcible operation condition is met can be determined from the detection result of the accelerator sensor 34. "Accelerator off" means that the accelerator pedal 16 is not being operated by the operator of the forklift 10.

[0055] If the forced operation release condition is met when the control device 31 is in the forced operation state S40, the control device 31 transitions to the normal control state S10. The forced operation release condition is met when at least one of the first release condition, the second release condition, and the third release condition is met.

[0056] First release condition: There are no more obstacles in the departure restriction area AA1. Second release condition: The detection result of the direction sensor 35 is forward. Third release condition: After the start restriction is activated, the parking brake 38 is switched from inactive to active.

[0057] The third release condition can be determined from the detection result of the parking switch 37. <Display Control> Next, a description will be given of the display control performed by the control device 31. The display control is a control for updating the display content of the display unit 71.

[0058] 6, in step S1, the control device 31 determines whether or not the vehicle is in a start-prohibited state S30. If the determination result in step S1 is positive, the control device 31 performs processing in step S2. If the determination result in step S1 is negative, the control device 31 performs the determination in step S3.

[0059] 6 and 7, in step S2, the control device 31 displays a notification screen 72 on the display unit 71. The notification screen 72 is a screen that notifies the operator of the forklift 10 of the presence of an obstacle.

[0060] 7, when the notification screen 72 is displayed on the display unit 71, the display unit 71 includes an icon I1, a rear right display area 73, a rear left display area 74, and a rear center display area 75. The notification screen 72 may display information about the status of the forklift 10. For example, the notification screen 72 may display the remaining capacity of the battery that serves as the power source for the travel motor 41.

[0061] The icon I1 resembles a forklift 10. The rear right display area 73 indicates the area behind and to the right of the icon I1. The rear left display area 74 indicates the area behind and to the left of the icon I1. The rear center display area 75 is the area between the rear right display area 73 and the rear left display area 74. The rear right display area 73 corresponds to the right restricted area NR. The rear left display area 74 corresponds to the left restricted area NL. The rear center display area 75 corresponds to the center restricted area N.

[0062] When the control device 31 is in the start prohibition state S30, the start of the forklift 10 is restricted. In addition, an alarm is also issued in the start prohibition state S30. An obstacle that is the cause of the start prohibition state S30, i.e., the obstacle that is restricting the progress of the forklift 10 and causing the alarm, is referred to as a causal obstacle. When an obstacle is present in the planned travel area, the control device 31 enters the start prohibition state S30. An obstacle that meets the specific condition, that is, the presence of the obstacle in the planned travel area, is referred to as a causal obstacle.

[0063] As shown in Fig. 4, an example will be described in which obstacles exist in both the right restricted area NR and the left restricted area NL. The obstacle existing in the right restricted area NR is referred to as a right obstacle O1, and the obstacle existing in the left restricted area NL is referred to as a left obstacle O2. When the operator of the forklift 10 attempts to start the forklift 10 backward and to the right, the control device 31 enters the start prohibition state S30, regarding the right obstacle O1 as the causative obstacle. In this case, as shown in Fig. 7, a first image I2 and a second image I3 are displayed on the notification screen 72 of the display unit 71.

[0064] The first image I2 shows an obstacle different from the causative obstacle. The first image I2 is an icon showing an obstacle. The second image I3 shows the causative obstacle. The second image I3 is an icon showing the causative obstacle. The second image I3 is highlighted compared to the first image I2 so that the operator of the forklift 10 can easily recognize the presence of the causative obstacle. In the example shown in FIG. 7, the second image I3 is highlighted by adding an exclamation mark. It is sufficient that the first image I2 and the second image I3 can show an obstacle. For example, text may be displayed as the first image I2 and the second image I3.

[0065] The first image I2 is displayed on the display unit 71 according to the position of an obstacle different from the causative obstacle. When an obstacle is present in a restricted area N, NL, NR that is different from the planned travel area within the departure restricted area AA1, the control device 31 displays the first image I2 in the display areas 73, 74, 75 corresponding to the restricted area N, NL, NR. In the example shown in Fig. 4, the first image I2 is displayed in the rear left display area 74 that corresponds to the left restricted area NL.

[0066] The second image I3 is displayed on the display unit 71 according to the position of the causative obstacle. When an obstacle is present in the planned travel area, the control device 31 displays the second image I3 in the display areas 73, 74, 75 corresponding to the planned travel area. In the example shown in Fig. 4, the second image I3 is displayed in the rear right display area 73 corresponding to the right restricted area NR.

[0067] 7, the first image I2 is displayed in one of the rear right display area 73, the rear left display area 74, and the rear center display area 75. Depending on the positions and number of obstacles, the first image I2 is displayed in two of the rear right display area 73, the rear left display area 74, and the rear center display area 75. Similarly, depending on the positions and number of causative obstacles, the second image I3 is displayed in two of the rear right display area 73, the rear left display area 74, and the rear center display area 75.

[0068] When the control device 31 is in the start prohibition state S30, the forklift 10 is stopped. It can be said that the control device 31 is displaying the first image I2 and the second image I3 on ​​the display unit 71 while the forklift 10 is stopped. After completing the processing of step S2, the control device 31 ends the display control.

[0069] In step S3, the control device 31 determines whether or not the forced operation state S40 is in effect. If the determination result in step S3 is positive, the control device 31 performs the determination in step S4. If the determination result in step S3 is negative, the control device 31 performs the process in step S5.

[0070] In step S4, the control device 31 determines whether the forklift 10 is stopped. If the determination result in step S4 is positive, the control device 31 performs the process of step S2. As a result, when the control device 31 is in the forced operation state S40 and the forklift 10 is stopped, the notification screen 72 is displayed. If the determination result in step S4 is negative, the control device 31 performs the process of step S5.

[0071] In step S5, the control device 31 hides the notification screen 72. That is, the first image I2 and the second image I3 are no longer displayed on the display unit 71. The control device 31 may display a progress screen instead of the notification screen 72. The progress screen is a screen on which information related to the progress of the forklift 10, such as the speed of the forklift 10, is displayed. After completing the processing of step S5, the control device 31 ends the display control.

[0072] [Operation of this embodiment] In order to prevent contact between the forklift 10 and an obstacle, the control device 31 performs start restriction control. In the start prohibition state S30, if an obstacle is present in the planned travel area of ​​the start restriction area AA1, the start of the forklift 10 is restricted and a warning is issued, with the obstacle being regarded as a causative obstacle. In this case, if an obstacle is present in an area of ​​the start restriction area AA1 that is different from the planned travel area, the causative obstacle and an obstacle different from the causative obstacle are present in the start restriction area AA1. If the causative obstacle and an obstacle different from the causative obstacle are present in the start restriction area AA1, it may be difficult for the operator of the forklift 10 to recognize which obstacle is causing the start restriction of the forklift 10 and the warning.

[0073] The control device 31 can notify the operator of the forklift 10 of the presence of a causal obstacle by displaying the second image I3 on ​​the display unit 71. In addition, by displaying the first image I2 and the second image I3 according to the positional relationship between the forklift 10 and the obstacle, the operator of the forklift 10 can recognize which obstacle is the causal obstacle.

[0074] [Effects of this embodiment] (1) When notifying an obstacle other than the causative obstacle, the control device 31 displays the first image I2 on the display unit 71. When notifying a causative obstacle, the control device 31 displays the second image I3 on ​​the display unit 71. This allows the control device 31 to notify the operator of the forklift 10 of the presence of the causative obstacle.

[0075] (2) When the travel of the forklift 10 is restricted at the time of starting the forklift 10, the control device 31 displays the second image I3 on ​​the display unit 71. After the forklift 10 has started, the operator of the forklift 10 is often visually checking the load and the destination of the forklift 10, and may not view the display unit 71 even if the second image I3 is displayed on the display unit 71. Also, after the forklift 10 has started, a travel screen may be required to be displayed. On the other hand, when starting the forklift 10, it is easy for the operator of the forklift 10 to view the display unit 71. Also, in order to start the forklift 10, it is highly necessary to make the operator aware of the presence of a causative obstacle. By displaying the second image I3 on ​​the display unit 71 at the time of starting the forklift 10, the operator of the forklift 10 can be appropriately made aware of the presence of a causative obstacle.

[0076] (3) The control device 31 displays the second image I3 on ​​the display unit 71 when the forklift 10 is stopped. While the forklift 10 is moving, the operator of the forklift 10 is often visually checking the load and the destination of the forklift 10, and may not be able to visually check the display unit 71 even if the second image I3 is displayed on the display unit 71. By displaying the second image I3 on ​​the display unit 71 when the forklift 10 is stopped, the operator of the forklift 10 can be properly made aware of the presence of a causative obstacle.

[0077] (4) Based on the positional relationship between the forklift 10 and the causative obstacle, the control device 31 displays the second image I3 in at least one of the rear right display area 73, the rear left display area 74, and the rear center display area 75. Because the second image I3 is displayed according to the positional relationship between the forklift 10 and the causative obstacle, the operator of the forklift 10 can easily recognize the position of the causative obstacle.

[0078] [Example of change] The embodiment can be modified as follows: The embodiment and the following modifications can be combined with each other to the extent that they are not technically inconsistent.

[0079] The display unit 71 does not necessarily have to include the rear right display area 73, the rear left display area 74, and the rear center display area 75. In this case, the first image I2 or the second image I3 may be displayed at a position corresponding to the distance from the forklift 10 to the obstacle and the direction from the forklift 10 toward the obstacle. For example, the second image I3 may be displayed on the display unit 71 so that the distance between the icon I1 and the second image I3 increases as the distance from the forklift 10 to the causative obstacle increases. Furthermore, the second image I3 may be displayed on the display unit 71 so that the direction from the forklift 10 toward the causative obstacle coincides with the direction from the icon I1 toward the second image I3.

[0080] The control device 31 may display the notification screen 72 while the forklift 10 is moving forward. For example, the control device 31 may display the notification screen 72 while the forklift 10 is moving forward in the forced operation state S40.

[0081] If the planned travel area is changed so that the obstacle no longer exists in the planned travel area, the control device 31 may change the second image I3 to the first image I2. An explanation will be given using FIG. 4 as an example. Let us assume that, from the state shown in FIG. 4, the planned travel area is changed to the central restricted area N due to a change in the angle of the steering wheel 14 detected by the tire angle sensor 36. In this case, the right obstacle O1 changes from being the causal obstacle to being an obstacle different from the causal obstacle. The control device 31 changes the second image I3 displayed in the rear right display area 73 to the first image I2.

[0082] The control device 31 may display the first image I2 on the display unit 71 when notifying of an obstacle other than the causative obstacle, and the second image I3 when notifying of the causative obstacle. Therefore, the control device 31 does not need to change the positions at which the first image I2 and the second image I3 are displayed depending on the positional relationship between the forklift 10 and the obstacle. Furthermore, the control device 31 may not simultaneously display the first image I2 and the second image I3 on ​​the display unit 71. When only obstacles other than the causative obstacle are present in the departure restriction area AA1, the control device 31 may display only the first image I2 on the display unit 71. When only the causative obstacle is present in the departure restriction area AA1, the control device 31 may display only the second image I3 on ​​the display unit 71.

[0083] In the start restriction state S20, the control device 31 may display the second image I3 on ​​the display unit 71. In the start restriction state S20, the start of the forklift 10 is restricted if an obstacle exists in the start restriction area AA1. The presence of an obstacle in the start restriction area AA1 can be considered a specific condition.

[0084] The forklift 10 may be driven by an engine. In this case, the fourth prohibition condition is excluded from the start prohibition conditions. That is, the start prohibition condition is met when the first, second, and third prohibition conditions are all met. In addition, the forced operation condition is changed to the direction lever 17 being in the neutral position.

[0085] The obstacle detection unit 51 may detect the position of an obstacle present in the forward direction of the forklift 10. In this case, the stereo camera 52 is disposed facing forward of the forklift 10. When the obstacle detection unit 51 detects the position of an obstacle present in the forward direction of the forklift 10, the departure restriction area AA1 becomes an area extending forward from the forklift 10. In this case, the third prohibition condition and the second release condition are changed as follows.

[0086] Third prohibition condition: The detection result of the direction sensor 35 is forward. Second release condition: The detection result of the direction sensor 35 is reverse. The obstacle detection unit 51 may be capable of detecting the position of an obstacle present in either the reverse direction or the forward direction of the forklift 10. For example, a forward stereo camera 52 and a reverse stereo camera 52 may be provided, or a fisheye camera may be provided. In this case, the departure restriction area AA1 includes a forward area extending forward from the forklift 10 and a rear area extending rearward from the forklift 10. When the forklift 10 is to be moved forward, the control device 31 performs departure restriction control with the departure restriction area AA1 as the forward area. When the forklift 10 is to be moved backward, the control device 31 performs departure restriction control with the departure restriction area AA1 as the rear area.

[0087] When changing the departure restricted area AA1 as described above, the positions of the display unit 71 where the first image I2 and the second image I3 are displayed may be changed in accordance with the change in the departure restricted area AA1. For example, when the departure restricted area AA1 is an area extending in front of the forklift 10, the control device 31 may display the first image I2 and the second image I3 in positions corresponding to the front of the icon I1.

[0088] The obstacle detection unit 51 may use a monocular camera, a Time of Flight (ToF) camera, a Laser Imaging Detection and Ranging (LIDAR), a millimeter-wave radar, or the like instead of the stereo camera 52. The obstacle detection unit 51 may be equipped with a combination of multiple sensors, such as the stereo camera 52 and a LIDAR.

[0089] The warning unit 58 may be provided in a unit other than the obstacle detection unit 51. The alarm unit 58 may be directly activated by the control device 31. The forklift 10 may be capable of switching between automatic operation and manual operation.

[0090] The control device 31 does not have to issue a warning when in the start prohibition state S30. Similarly, the control device 31 does not have to issue a warning when in the forced operation state S40. Instead of the start prohibition state S30, a first alarm state may be set in which the start of the forklift 10 is not restricted and only an alarm is issued. Instead of the forced operation state S40, a second alarm state may be set in which the start of the forklift 10 is not restricted and only an alarm is issued. The strength of the alarm may be different between the first alarm state and the second alarm state. For example, the alarm may be stronger in the first alarm state than in the second alarm state. In this way, the forklift 10 may be capable of issuing at least one of restricting travel and issuing an alarm depending on the obstruction.

[0091] The obstacle notification device 70 of the industrial vehicle may be provided with a dedicated control device for controlling the display unit 71. That is, a control device for controlling the traveling operation and loading / unloading operation of the forklift 10 and a control device for controlling the display unit 71 may be provided separately.

[0092] The industrial vehicle may be a towing vehicle used to transport cargo, a picking lift used for picking work, or the like. [Explanation of symbols]

[0093] I1...icon, I2...first image, I3...second image, 10...forklift which is an industrial vehicle, 31...control device, 36...tire angle sensor, 51...obstacle detection unit, 70...obstacle notification device for industrial vehicle, 71...display unit, 73...rear right display area, 74...rear left display area, 75...rear center display area.

Claims

1. an obstacle detection unit that detects a positional relationship between the industrial vehicle and an obstacle; A display unit; a control device; an obstacle notification device for an industrial vehicle, which, when an obstacle present in an area set within a detectable range of the obstacle detection unit is determined to be a causing obstacle, sets an upper vehicle speed limit value when the causing obstacle exists, thereby restricting travel of the industrial vehicle when the industrial vehicle starts moving, The control device When notifying the driver of an obstacle different from the causative obstacle, a first image is displayed on the display unit; An obstacle notification device for an industrial vehicle that displays a second image, different from the first image, on the display unit when the progress of the industrial vehicle is restricted when the industrial vehicle starts and when notifying of the causing obstacle.

2. The obstacle notification device for an industrial vehicle according to claim 1 , wherein the control device displays the second image on the display unit when the industrial vehicle is stopped.

3. The display unit an icon that resembles a forklift, which is the industrial vehicle, and that includes a portion that resembles a fork of the forklift; When the protruding direction of the part is defined as the front direction of the icon, the display device includes a rear right display area that is behind the icon and to the right of the icon, a rear left display area that is behind the icon and to the left of the icon, and a rear center display area between the rear right display area and the rear left display area, The control device 3. The obstacle notification device for an industrial vehicle according to claim 1, wherein the second image is displayed in at least one of the rear right display area, the rear left display area, and the rear center display area based on the positional relationship between the industrial vehicle and the causative obstacle.

4. an obstacle notification device for an industrial vehicle according to claim 1; The steering wheel and a tire angle sensor for detecting the steering angle of the steering wheel, The control device determining a planned travel area of ​​the industrial vehicle from the tire angle sensor; An industrial vehicle in which, when the planned travel area coincides with the restricted area in which the causative obstacle exists among multiple restricted areas set in the area, the upper vehicle speed limit value is set to restrict the travel of the industrial vehicle when the industrial vehicle starts moving, and the second image is displayed on the display unit.

Images