Industrial vehicles

Abstract

To suppress interference between the first deceleration limit and the second deceleration limit.SOLUTION: A control device executes a first deceleration limit that sets a first deceleration upper limit value when the high lift / heavy object transport / unattended determination conditions are met. The control device sets a second deceleration upper limit value that sets a second deceleration upper limit value when the distance condition is met. When the high lift / heavy object transport / unattended determination conditions are met, the control device executes priority control that sets the first deceleration upper limit value as the deceleration upper limit value in preference to the second deceleration upper limit value.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present disclosure relates to industrial vehicles.

Background Art

[0002] The industrial vehicle disclosed in Patent Document 1 includes an obstacle detection unit and a control device. The obstacle detection unit detects the relative position between the industrial vehicle and an obstacle. The control device performs vehicle speed limitation according to the detection result of the obstacle detection unit. The control device performs deceleration limitation in accordance with the vehicle speed limitation. The control device performs control so that the deceleration of the industrial vehicle is below the deceleration upper limit value.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In industrial vehicles, various deceleration limitations may be performed according to the situation of the industrial vehicle. In this case, different deceleration upper limit values may be set for each deceleration limitation. When a plurality of conditions for performing deceleration limitation are satisfied, there is a risk that the deceleration limitations interfere with each other.

Means for Solving the Problems

[0005] An industrial vehicle that solves the above problems is an industrial vehicle comprising: a control device that decelerates the industrial vehicle at a deceleration of less than or equal to a set deceleration upper limit; and an obstacle detection unit that detects the relative distance between the industrial vehicle and an obstacle, wherein the control device performs a first deceleration upper limit when the high lifting height, heavy load transport, and driver departure determination conditions are met, which are met when the industrial vehicle is in a high lifting height state, the load weight is above a threshold state, or driver departure is detected; a second deceleration upper limit when the distance condition is met, which is met when the relative distance between the industrial vehicle and the obstacle is less than a predetermined distance threshold; and priority control when the high lifting height, heavy load transport, and driver departure determination conditions are met, the first deceleration upper limit is set as the deceleration upper limit with priority over the second deceleration upper limit.

[0006] When the conditions for high lift height, heavy object transport, and passenger departure are met, the control device prioritizes setting the first deceleration limit as the deceleration limit. This prevents interference between the first and second deceleration limits.

[0007] Regarding the above-mentioned industrial vehicle, the industrial vehicle may be equipped with a cargo handling device, and the conditions for determining high lifting height, heavy object transport, and passenger departure may include the condition that the lifting height of the cargo handling device is equal to or greater than a predetermined lifting height threshold.

[0008] Regarding the industrial vehicle described above, the industrial vehicle includes a display unit and an operating unit configured to change at least one of the upper limit of deceleration when the accelerator is released and the second upper limit of deceleration when the accelerator is released by being operated by the user. If the second upper limit of deceleration is higher than the upper limit of deceleration when the accelerator is released, the control device may display a warning on the display unit.

[0009] With respect to the above industrial vehicle, the control device may perform a third deceleration limit, setting a third deceleration limit as the deceleration limit when an impact exceeding a predetermined impact threshold is applied to the telematics terminal, and the priority control may also include setting the second deceleration limit as the deceleration limit with priority over the third deceleration limit when the distance condition is met.

[0010] With respect to the above-mentioned industrial vehicle, the control device may perform a fourth deceleration limit by setting the fourth deceleration limit as the deceleration limit when the battery fails, and the priority control may also include setting the second deceleration limit as the deceleration limit with priority over the fourth deceleration limit when the distance condition is met. [Effects of the Invention]

[0011] According to the present invention, interference between the first deceleration limit and the second deceleration limit can be suppressed. [Brief explanation of the drawing]

[0012] [Figure 1] This is a perspective view of a forklift. [Figure 2] Figure 1 is a schematic diagram of the forklift configuration. [Figure 3] This is a flowchart showing the obstacle detection control performed by the detection device shown in Figure 2. [Figure 4] This figure shows an example of a changeable screen displayed on the display unit in Figure 2. [Figure 5] Figure 2 is a flowchart showing the priority control performed by the control unit. [Modes for carrying out the invention]

[0013] The following describes one embodiment of an industrial vehicle. <Forklift> As shown in Figure 1, the forklift 10 comprises a body 11, two drive wheels 12 and 13, two steering wheels 14, and a cargo handling device 20. The two drive wheels 12 and 13 are spaced apart in the vehicle width direction. The two steering wheels 14 are adjacent to each other in the vehicle width direction. The two steering wheels 14 are positioned centrally between the drive wheels 12 and 13 in the vehicle width direction. If the two adjacent steering wheels 14 are considered as one steering wheel 14, the forklift 10 can be considered a three-wheeled forklift. The forklift 10 is equipped with a driver's seat 15. The forklift 10 is operated by a driver seated in the driver's seat 15. In the following description, front, rear, left, and right refer to the front, rear, left, and right of the forklift 10. The forklift 10 is an example of an industrial vehicle.

[0014] The cargo handling device 20 includes a mast 21. The mast 21 is located at the front of the vehicle body 11. The cargo handling device 20 includes two forks 22. A load L is loaded onto the forks 22. The forks 22 are mounted to be able to move up and down along the mast 21. The cargo handling device 20 includes a lift cylinder 23. The lift cylinder 23 is a hydraulic cylinder. The forks 22 move up and down by the extension and retraction of the lift cylinder 23.

[0015] As shown in Figure 2, the forklift 10 includes a control device 31. The control device 31 includes a processor 32 and a storage unit 33. The processor 32 is, 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 a program for operating the forklift 10. The storage unit 33 stores program code or instructions configured to cause the processor 32 to execute processing. The storage unit 33, i.e., the computer-readable medium, includes any available medium that can be accessed by a general-purpose or dedicated computer. The control device 31 may be composed of hardware circuits such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). The control device 31, which is a processing circuit, may include one or more processors that operate according to a computer program, one or more hardware circuits such as an ASIC or FPGA, or a combination thereof.

[0016] The forklift 10 is equipped with an accelerator pedal 16. The accelerator pedal 16 is operated by the driver who is seated in the forklift 10. The forklift 10 is equipped with an accelerator sensor 34. The accelerator sensor 34 detects the amount of movement of the accelerator pedal 16. The accelerator sensor 34 outputs an electrical signal to the control device 31 corresponding to the amount of movement of the accelerator pedal 16. The control device 31 can recognize the amount of movement of the accelerator pedal 16 from the electrical signal from the accelerator sensor 34.

[0017] The forklift 10 is equipped with a direction control unit 17. The direction control unit 17 is, for example, a lever. The direction control unit 17 tilts forward or backward from a neutral position.

[0018] The forklift 10 includes a direction sensor 35. The direction sensor 35 detects the operation direction of the direction operation unit 17. The direction sensor 35 outputs an electric signal corresponding to the operation direction of the direction operation unit 17 to the control device 31. The control device 31 can recognize the operation direction of the direction operation unit 17 based on the electric signal from the direction sensor 35.

[0019] The forklift 10 includes a tire angle sensor 36. The tire angle sensor 36 detects the steering angle of the steering wheel 14. The tire angle sensor 36 outputs an electric signal corresponding to the steering angle to the control device 31. The control device 31 can recognize the steering angle based on the electric signal from the tire angle sensor 36.

[0020] The forklift 10 includes a lift height sensor 37. The lift height sensor 37 is a sensor for causing the control device 31 to determine whether the lift height of the cargo handling device 20 is a low lift height or a high lift height. The lift height of the cargo handling device 20 is the height from the road surface to the fork 22. When the lift height of the cargo handling device 20 is less than a predetermined lift height threshold value, the lift height of the cargo handling device 20 is a low lift height. When the lift height of the cargo handling device 20 is equal to or greater than the lift height threshold value, the lift height of the cargo handling device 20 is a high lift height. The lift height threshold value can be arbitrarily set. The lift height sensor 37 is, for example, a switch whose on / off state is switched when the lift height of the cargo handling device 20 reaches the lift height threshold value. The lift height sensor 37 may be able to detect the lift height of the cargo handling device 20 as a numerical value. The control device 31 can recognize whether the lift height of the cargo handling device 20 is a low lift height or a high lift height from the electric signal of the lift height sensor 37.

[0021] The forklift 10 includes a load sensor 38. The load sensor 38 outputs an electric signal corresponding to the weight of the load L loaded on the fork 22 to the control device 31. The load sensor 38 is, for example, a pressure sensor that detects the internal pressure of the lift cylinder 23. The control device 31 can recognize the weight of the load L based on the electric signal of the load sensor 38.

[0022] The forklift 10 is equipped with a seat switch 39. The seat switch 39 is a switch that is turned on and off depending on whether, for example, the driver is seated in the driver's seat 15. When the driver is seated in the driver's seat 15, the seat switch 39 is turned on. When the driver is not seated in the driver's seat 15, the seat switch 39 is turned off. The seat switch 39 only needs to be capable of allowing the control device 31 to determine whether or not the driver is seated in the driver's seat 15, and may be, for example, a pressure sensor. The control device 31 can recognize whether or not the driver is seated in the driver's seat 15 by the electrical signal from the seat switch 39.

[0023] The forklift 10 is equipped with a telematics terminal 40. The telematics terminal 40 is a terminal for communicating with external devices via a communication network. The telematics terminal 40 includes a Telematics Control Unit (TCU) 41. The TCU 41 controls the telematics terminal 40. The hardware configuration of the TCU 41 may be the same as that of the control device 31, for example.

[0024] The telematics terminal 40 is equipped with an impact sensor 42. The impact sensor 42 detects the magnitude of the impact applied to the telematics terminal 40. The impact sensor 42 outputs an electrical signal to the TCU 41 corresponding to the magnitude of the impact applied to the telematics terminal 40. The impact sensor 42 is, for example, an accelerometer. The TCU 41 can recognize the magnitude of the impact applied to the telematics terminal 40 based on the electrical signal from the impact sensor 42.

[0025] The forklift 10 is equipped with a drive motor 51. The drive motor 51 drives the drive wheels 12 and 13, causing the forklift 10 to move. A drive motor 51 is provided for each of the drive wheels 12 and 13.

[0026] The forklift 10 is equipped with a travel control device 52. The travel control device 52 is a motor driver that controls the rotational speed of the travel motor 51. The forklift 10 is equipped with a rotation speed sensor 53. The rotation speed sensor 53 detects the rotation speed of the travel motor 51. The rotation speed sensor 53 is, for example, a rotary encoder. The rotation speed sensor 53 outputs an electrical signal corresponding to the rotation speed of the travel motor 51 to the travel control device 52. The travel control device 52 can recognize the rotation speed of the travel motor 51 from the electrical signal of the rotation speed sensor 53.

[0027] The forklift 10 is equipped with a battery 61. The battery 61 is a power source for the drive motor 51 and at least one of the electrical components. The battery 61 is a rechargeable secondary battery. The battery 61 is, for example, a lithium-ion secondary battery. As used herein, the expression "at least one" means "one or more" of the desired options. For example, as used herein, the expression "at least one" means "only one option" or "both of the two options" if there are two options. As another example, as used herein, the expression "at least one" means "only one option" or "a combination of two or more any options" if there are three or more options.

[0028] The forklift 10 is equipped with a monitoring device 62. The monitoring device 62 monitors the battery 61. The monitoring device 62 is, for example, a battery management system. Monitoring of the battery 61 includes, for example, monitoring the charge level of the battery 61 and monitoring at least one of the failures of the battery 61. Failures of the battery 61 include over-discharge of the battery 61 and over-charging of the battery 61.

[0029] The forklift 10 is equipped with an obstacle detection unit 71. The obstacle detection unit 71 detects the location of obstacles. The obstacle detection unit 71 is equipped with a stereo camera 72. The stereo camera 72 is equipped with two cameras. The stereo camera 72 takes images with each of the two cameras. The stereo camera 72 is positioned to provide a bird's-eye view of the road surface on which the forklift 10 travels, from above the forklift 10. In this embodiment, the stereo camera 72 takes images of the area behind the forklift 10. Therefore, the obstacles detected by the obstacle detection unit 71 are obstacles behind the forklift 10. The stereo camera 72 may also be provided to take images of the area in front of the forklift 10. In this case, the obstacle detection unit 71 will detect obstacles in front of the forklift 10.

[0030] The obstacle detection unit 71 includes a detection device 73. The hardware configuration of the detection device 73 is, for example, the same as that of the control device 31. The detection device 73 detects the relative distance between the forklift 10 and an obstacle located behind it by repeatedly performing the following obstacle detection control at a predetermined control cycle.

[0031] <Obstacle detection control> As shown in Figure 3, in step S10, the detection device 73 acquires an image from the stereo camera 72.

[0032] Next, in step S11, the detection device 73 acquires a disparity image by performing stereo processing. The disparity image associates the disparity [px] with each pixel. Next, in step S12, the detection device 73 derives the coordinates of the feature points in the world coordinate system, which is a coordinate system in real space. The world coordinate system is a coordinate system in which, with the forklift 10 positioned on a horizontal plane, the axis extending in the direction of the width of the forklift 10 in the horizontal direction is the X-axis, the axis perpendicular to the X-axis in the horizontal direction is the Y-axis, and the axis extending in the vertical direction is the Z-axis. The detection device 73 derives the coordinates of the feature points in the camera coordinate system from the baseline length of the stereo camera 72, the focal length of the stereo camera 72, and the disparity image obtained in step S11. The camera coordinate system is a coordinate system with the stereo camera 72 as the origin. The detection device 73 converts the coordinates of the feature points in the camera coordinate system to coordinates in the world coordinate system.

[0033] Next, in step S13, the detection device 73 extracts obstacles by clustering feature points. The detection device 73 collects a set of feature points that are assumed to represent the same obstacle from among the feature points that represent a part of the obstacle, and extracts this point group as an obstacle. The clustering of feature points performed in step S13 can be done using various methods. Obstacles include people and objects. Objects are obstacles other than people.

[0034] Next, in step S14, the detection device 73 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. More specifically, the X coordinate of the obstacle in the world coordinate system represents the distance from the origin to the obstacle in the left-right direction. The Y coordinate of the obstacle in the world coordinate system represents the distance from the origin to the obstacle in the front-back direction. The origin of the world coordinate system is, for example, a coordinate system where the X and Y coordinates are the placement position of the stereo camera 72 and the Z coordinate is the road surface. It is also possible to derive the Euclidean distance from the placement position of the stereo camera 72 to the obstacle from the X and Y coordinates. The Z coordinate of the obstacle in the world coordinate system represents the height of the obstacle from the road surface.

[0035] Next, in step S15, the detection device 73 performs a person detection process. The person detection process determines whether an obstacle is a person or not. In this embodiment, the detection device 73 performs the person detection process on an image captured by one of the two cameras of the stereo camera 72. The detection device 73 converts the coordinates of the obstacle in the world coordinate system obtained in step S14 into camera coordinates, and converts the camera coordinates into the coordinates of the image captured by the camera. The detection device 73 performs the person detection process on the coordinates of the obstacle in the image. The person detection process is performed, for example, using feature quantities. The detection device 73 extracts feature quantities from the coordinates of the obstacle in the image. The feature quantities are, for example, HOG (Histogram of Oriented Gradients) features or Haar-Like features. The detection device 73 determines whether an obstacle is a person or not by comparing the feature quantities extracted from the image with dictionary data. The dictionary data is, for example, feature quantity data extracted from each of multiple images in which a person is pictured. Obstacles that were not determined to be a person in step S15 are objects.

[0036] As shown in Figure 2, the obstacle detection unit 71 includes an alarm unit 74. The alarm unit 74 is a device that alerts the driver of the forklift 10. The alarm unit 74 includes a buzzer 75 that provides an audible alarm and a lamp 76 that provides a light alarm.

[0037] The forklift 10 includes a display unit 81. The display unit 81 includes a display 82. The display 82 is positioned in a location visible to the driver. The display unit 81 also includes an operation unit 83. The operation unit 83 is positioned in a location accessible to the driver of the forklift 10, for example. The operation unit 83 may consist of physical buttons or a touch panel. The operation unit 83 is operated, for example, to change the display content of the display 82 or to change various settings of the forklift 10.

[0038] <Control performed by the control device> The control device 31, TCU 41, driving control device 52, monitoring device 62, and detection device 73 are configured to acquire information from each other. The control device 31, TCU 41, driving control device 52, monitoring device 62, and detection device 73 acquire information from each other by communicating according to vehicle communication protocols such as CAN (Controller Area Network) or LIN (Local Interconnect Network).

[0039] 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 rotational speed and direction of each drive motor 51 provided for each drive wheel 12, 13, the gear ratio, the outer diameter of the drive wheels 12, 13, and the steering angle detected by the tire angle sensor 36. The rotational speed and direction of the drive motor 51 can be obtained from the travel control device 52. The gear ratio and the outer diameter of the drive wheels 12, 13 can be stored in the memory unit 33 in advance. The control device 31 may also derive the direction of travel of the forklift 10. The direction of travel of the forklift 10 is either forward or reverse.

[0040] The control device 31 activates the alarm unit 74 by transmitting an alarm command to the obstacle detection unit 71. More specifically, the obstacle detection unit 71 is equipped with an activation unit that activates the alarm unit 74, and upon receiving an alarm command, the activation unit activates the alarm unit 74.

[0041] <Vehicle speed control performed by the control device> The control device 31 calculates the target vehicle speed from the detection result of the accelerator sensor 34. The control device 31 calculates the target rotational speed from the target vehicle speed. The target rotational speed is the rotational speed required for the forklift 10 to reach the target vehicle speed. The control device 31 generates a command that includes information indicating the target rotational speed. The control device 31 outputs this command to the travel control device 52. The travel control device 52 controls the travel motor 51 to follow the target rotational speed specified in the command. As a result, the forklift 10 travels in accordance with the target vehicle speed.

[0042] The control device 31 limits the vehicle speed. For example, the control device 31 limits the vehicle speed by setting a vehicle speed upper limit [km / h]. The vehicle speed upper limit is lower than the maximum speed that the forklift 10 can reach. If the target vehicle speed calculated from the detection result of the accelerator sensor 34 is less than the vehicle speed upper limit, the control device 31 calculates the target rotational speed from the target vehicle speed calculated from the detection result of the accelerator sensor 34. If the target vehicle speed calculated from the detection result of the accelerator sensor 34 is equal to or greater than the vehicle speed upper limit, the control device 31 calculates the target rotational speed using the vehicle speed upper limit instead of the target vehicle speed. This prevents the speed of the forklift 10 from exceeding the vehicle speed upper limit.

[0043] The control device 31 limits the deceleration when the vehicle decelerates due to a speed limit. The control device 31 limits the deceleration by setting a deceleration upper limit [m / s^2]. The deceleration upper limit is lower than the maximum deceleration that the forklift 10 can achieve. The control device 31 controls the forklift 10 so that its deceleration does not exceed the deceleration upper limit. For example, the control device 31 outputs a command to the travel control device 52 indicating a target deceleration. The travel control device 52 controls the rotation speed of the travel motor 51 so that the deceleration of the forklift 10 becomes the target deceleration. When the deceleration upper limit is set, the control device 31 outputs a value less than or equal to the deceleration upper limit as the target deceleration to the travel control device 52. This prevents the forklift 10 from decelerating beyond the deceleration upper limit.

[0044] The control device 31 sets speed limits and deceleration limits according to the status of the forklift 10. The upper limit of the speed limit and the upper limit of the deceleration limit may vary depending on the status of the forklift 10. The speed limits and deceleration limits that are set according to the status of the forklift 10 will be described below.

[0045] <Speed ​​limits and deceleration limits according to the condition of the cargo handling equipment> The vehicle speed limit and deceleration limit according to the status of the cargo handling device 20 will be described. The control device 31 performs vehicle speed limit and deceleration limit based on at least one of the lifting height of the cargo handling device 20 and the weight of the load L. In this embodiment, the control device 31 performs vehicle speed limit and deceleration limit based on the lifting height of the cargo handling device 20 and the weight of the load L. When the lifting height of the cargo handling device 20 is high, the control device 31 performs vehicle speed limit according to the weight of the load L. When the lifting height of the cargo handling device 20 is high, the control device 31 lowers the vehicle speed limit as the weight of the load L increases. The control device 31 may continuously lower the vehicle speed limit as the weight of the load L increases, or it may gradually lower the vehicle speed limit as the weight of the load L increases.

[0046] The control device 31 lowers the deceleration limit as the weight of the load L increases when the lifting height of the cargo handling device 20 is at a high lifting height. The control device 31 may continuously lower the deceleration limit in proportion to the weight of the load L, or it may gradually lower the deceleration limit as the weight of the load L increases. The high lifting height, heavy object transport, and departure detection conditions are conditions in which at least one of the following is met: the forklift 10 is at a high lifting height, the load L is above a threshold, or departure is detected.

[0047] The high lifting height, heavy object transport, and departure determination conditions used in the deceleration limit according to the status of the cargo handling device 20 are designated as the first high lifting height, heavy object transport, and departure determination conditions. The deceleration limit according to the status of the cargo handling device 20 is an example of the first deceleration limit. The upper limit of deceleration set in the deceleration limit according to the status of the cargo handling device 20 is designated as the cargo handling deceleration upper limit. The cargo handling deceleration upper limit is an example of the first deceleration upper limit.

[0048] The upper limit of the cargo handling deceleration may be set to different values ​​depending on whether the forklift 10 is moving straight or turning. Whether the forklift 10 is moving straight or turning can be determined from the steering angle. The control device 31 may set the upper limit of the cargo handling deceleration lower when the forklift 10 is turning than when the forklift 10 is moving straight. The control device 31 may also set the upper limit of the cargo handling deceleration lower as the turning radius decreases.

[0049] A weight threshold may be set for the weight of the load L. The control device 31 may also impose vehicle speed and deceleration limits when the lifting height of the cargo handling device 20 is high lifting height and the weight of the load L is equal to or greater than the weight threshold. In this case, the first high lifting height, heavy object transport, and driver departure determination condition is that the lifting height of the cargo handling device 20 is high lifting height and the weight of the load L is equal to or greater than the weight threshold.

[0050] <Speed ​​and deceleration limits due to driver leaving the vehicle> This section explains the vehicle speed limit and deceleration limit due to the driver leaving the seat. When the control device 31 recognizes, via the seat switch 39, that the driver is not seated in the driver's seat 15, it imposes a vehicle speed limit and deceleration limit. If the driver is away from the seat, the conditions for high lift height, heavy object transport, and driver leaving the seat are met. The high lift height, heavy object transport, and driver leaving the seat conditions used for the deceleration limit due to the driver leaving the seat are referred to as the second high lift height, heavy object transport, and driver leaving the seat conditions. The driver leaving the seat deceleration limit is an example of the first deceleration limit. The upper limit of deceleration set for the driver leaving the seat deceleration limit is referred to as the driver leaving the seat deceleration upper limit. The driver leaving the seat deceleration upper limit is an example of the first deceleration upper limit.

[0051] <Speed ​​and deceleration restrictions due to obstacles> The following describes speed and deceleration limits due to obstacles. The control device 31 can recognize the location of obstacles from the detection device 73. The control device 31 imposes speed and deceleration limits when a distance condition is met, which is when the relative distance between the forklift 10 and the obstacle is less than a predetermined distance threshold. For example, by setting an area that extends from the forklift 10 toward the rear of the forklift 10, the area within that area can be considered to be less than the distance threshold. Then, the control device 31 imposes speed and deceleration limits when an obstacle is present within the area. The control device 31 may lower the upper speed limit and deceleration limit as the distance from the forklift 10 to the obstacle decreases. For example, the above-mentioned area may be divided into a first deceleration area and a second deceleration area that is further from the forklift 10 than the first deceleration area. Then, when the obstacle is located in the first deceleration area, the upper speed limit and deceleration limit may be lower than when the obstacle is located only in the second deceleration area. The distance threshold can be set arbitrarily. The distance threshold is set to a distance at which, for example, if the forklift 10 starts to decelerate when the relative distance between the forklift 10 and the obstacle reaches the distance threshold, the forklift 10 can stop before reaching the obstacle.

[0052] Speed ​​and deceleration limits due to obstacles may be applied when the forklift 10 is moving in the direction in which the obstacle detection unit 71 detects an obstacle. In this embodiment, the obstacle detection unit 71 detects an obstacle behind the forklift 10. Therefore, speed and deceleration limits according to the position of the obstacle may be applied only when the forklift 10 is moving in reverse. The control device 31 may determine the direction of travel from the rotation direction of the travel motor 51, or from the operating direction of the direction control unit 17.

[0053] Speed ​​and deceleration limits due to obstacles may be applied when an obstacle is located on the expected trajectory of the forklift 10. The expected trajectory of the forklift 10 is the location that the forklift 10 is expected to pass if it continues to move at the current speed and steering angle. The control device 31 derives the expected trajectory in the world coordinate system from the speed and steering angle. This allows the control device 31 to determine whether or not an obstacle is located on the expected trajectory.

[0054] The control device 31 may set different vehicle speed limits and deceleration limits depending on whether the obstacle is an object or a person. For example, the vehicle speed limit when the obstacle is a person may be higher than the vehicle speed limit when the obstacle is an object. For example, the deceleration limit when the obstacle is an object may be higher than the deceleration limit when the obstacle is a person. In this embodiment, the deceleration limit can be arbitrarily changed by the manufacturer, seller, or operator of the forklift 10. For example, the manufacturer, seller, or operator can change the deceleration limit by operating the control unit 83. The manufacturer, seller, or operator is an example of a user. The deceleration limit may also be changeable by an external terminal that can be connected to the forklift 10.

[0055] As shown in Figure 4, when the manufacturer, seller, or operator of the forklift 10 changes the deceleration limit, a screen for the change is displayed on the display unit 82. In the example shown in Figure 4, the display unit 82 displays item display A1 and deceleration display A2. The display contents of the display unit 82 are updated by the control device 31. The control device 31 may directly control the display unit 82. If the display unit 81 includes a display controller that controls the display unit 82, the control device 31 may control the display unit 82 via the display controller.

[0056] Item display A1 shows the deceleration limit values ​​that can be changed by operating the operation unit 83. In the example shown in Figure 4, the accelerator-off deceleration limit, the deceleration limit when a person is detected, and the deceleration limit when an object is detected are displayed in item display A1. The accelerator-off deceleration limit is the deceleration limit when the accelerator is off, that is, when the accelerator pedal 16 is not being operated. The deceleration limit when a person is detected is the deceleration limit when deceleration is limited due to an obstacle, and that obstacle is a person. The deceleration limit when an object is detected is the deceleration limit when deceleration is limited due to an obstacle, and that obstacle is an object.

[0057] The deceleration display A2 shows the deceleration limit value corresponding to the item displayed in item display A1. In this embodiment, a level corresponding to the magnitude of the deceleration limit value is displayed in the deceleration display A2. The higher the level, the higher the deceleration limit value. The deceleration limit value corresponding to the level is predetermined. The deceleration limit value is changed by changing the level by operating the operation unit 83. That is, the forklift 10 of this embodiment can change the deceleration limit value in stages by changing the level. The deceleration limit value may also be changed by inputting the value of the deceleration limit value itself. The deceleration limit value when a person is detected must be less than or equal to the accelerator-off deceleration limit value. The deceleration limit value when an object is detected must be less than or equal to the accelerator-off deceleration limit value. If the deceleration limit value when a person is detected is changed to a value higher than the accelerator-off deceleration limit value, the deceleration limit value when a person is detected will be the same value as the accelerator-off deceleration limit value. If the deceleration limit value when an object is detected is changed to a value higher than the accelerator-off deceleration limit value, the deceleration limit value when an object is detected will be the same value as the accelerator-off deceleration limit value. If the deceleration limit when a person is detected becomes higher than the deceleration limit when the accelerator is released due to a change in the deceleration limit when the accelerator is released or when a person is detected, the control device 31 may display a warning. The warning may be displayed, for example, by flashing a level corresponding to the deceleration limit when a person is detected, or by displaying an error on the display unit 82. The control device 31 may also display a warning if the deceleration limit when an object is detected becomes higher than the deceleration limit when the accelerator is released due to a change in the deceleration limit when the accelerator is released or when a deceleration limit when an object is detected. At least one of the deceleration limit when the accelerator is released, the deceleration limit when a person is detected, and the deceleration limit when an object is detected may be changeable by operating the operation unit 83.

[0058] The deceleration limit imposed by obstacles is the second deceleration limit. The upper limit of deceleration set by the deceleration limit imposed by obstacles is the second upper limit of deceleration. When speed and deceleration limits are imposed due to an obstacle, the alarm unit 74 may issue a warning. The control device 31 may change the type of warning depending on whether the obstacle is a person or an object. The type of warning may be, for example, a warning issued by both the lamp 76 and the buzzer 75, a warning issued by either the lamp 76 or the buzzer 75, the flashing interval of the lamp 76, or the volume of the sound emitted by the buzzer 75. The control device 31 may also change the type of warning depending on the relative distance between the forklift 10 and the obstacle.

[0059] <Vehicle speed and deceleration limits due to impact to the telematics terminal> This section describes the vehicle speed limit and deceleration limit imposed when the telematics terminal 40 is subjected to an impact. When the telematics terminal 40 is subjected to an impact, the control device 31 acquires data from the telematics terminal 40 indicating the magnitude of the impact. The control device 31 imposes a vehicle speed limit and deceleration limit when an impact condition is met, which is met when the magnitude of the impact applied to the telematics terminal 40 is equal to or greater than a predetermined impact threshold. The impact threshold can be set arbitrarily. For example, the impact threshold can be set to an impact of a magnitude that can affect the operation of the telematics terminal 40. The determination of whether or not the impact condition is met may be made by the TCU 41. In this case, the TCU 41 should notify the control device 31 if the impact condition is met. The deceleration limit imposed when the telematics terminal 40 is subjected to an impact is the third deceleration limit. The upper limit of deceleration set by the deceleration limit imposed when the telematics terminal 40 is subjected to an impact is the third deceleration upper limit.

[0060] <Vehicle speed and deceleration limits due to battery failure> The following describes the vehicle speed limit and deceleration limit due to battery 61 failure. When the monitoring device 62 determines that the battery 61 has failed, the control device 31 obtains data from the monitoring device 62 indicating that the battery 61 has failed. If the failure conditions that apply when the battery 61 fails are met, the control device 31 sets speed limits and deceleration limits for the forklift 10. The deceleration limit due to battery 61 failure is the fourth deceleration limit. The upper limit of deceleration set by the deceleration limit due to battery 61 failure is the fourth deceleration upper limit.

[0061] <Priority Control> As described above, the control device 31 applies various deceleration limits depending on the status of the forklift 10. Depending on the status of the forklift 10, multiple conditions for applying deceleration limits may be met. For example, both the distance condition and the conditions for lifting height, heavy object transport, and driver leaving the position may be met. Since different deceleration limits may be set for each deceleration limit, it is necessary to determine which of the deceleration limits should be prioritized. The control device 31 determines which of the deceleration limits should be prioritized by the following priority control.

[0062] As shown in Figure 5, in step S21, the control device 31 determines whether the conditions for high lift height, heavy object transport, and departure from seat are met. If the determination result in step S21 is positive, the control device 31 performs the process in step S22. If the determination result in step S21 is negative, the control device 31 performs the process in step S23. In this embodiment, step S21 is positive if at least one of the first high lift height, heavy object transport, and departure from seat conditions and the second high lift height, heavy object transport, and departure from seat conditions are met.

[0063] In step S22, the control device 31 sets a first deceleration limit as the deceleration limit. If the first high lifting height, heavy object transport, and departure determination conditions are met, and the second high lifting height, heavy object transport, and departure determination conditions are not met, the control device 31 sets the cargo handling deceleration limit as the deceleration limit. If the second high lifting height, heavy object transport, and departure determination conditions are met, and the first high lifting height, heavy object transport, and departure determination conditions are not met, the control device 31 sets the departure deceleration limit as the deceleration limit. The deceleration limit to be set when both the first high lifting height, heavy object transport, and departure determination conditions and the second high lifting height, heavy object transport, and departure determination conditions are met can be predetermined as either the cargo handling deceleration limit or the departure deceleration limit. If the conditions for high lift height, heavy object transport, and departure are met in steps S21 and S22, the first deceleration limit is set as the deceleration limit, taking precedence over the second deceleration limit.

[0064] In step S23, the control device 31 determines whether the distance condition is met. If the determination result in step S23 is positive, the control device 31 performs the process in step S24. If the determination result in step S23 is negative, the control device 31 performs the process in step S25.

[0065] In step S24, the control device 31 sets a second deceleration limit as the deceleration limit. If the distance condition is met in steps S23 and S24, the second deceleration limit is set with priority over the third and fourth deceleration limits as the deceleration limit.

[0066] In step S25, the control device 31 determines whether at least one of the impact condition and the failure condition is met. If the determination result in step S25 is affirmative, the control device 31 performs the process in step S26. If the determination result in step S25 is negative, the control device 31 terminates priority control.

[0067] In step S26, the control device 31 sets either the third deceleration limit or the fourth deceleration limit as the deceleration limit. If the impact condition is met and the failure condition is not met, the control device 31 sets the third deceleration limit as the deceleration limit. If the failure condition is met and the impact condition is not met, the control device 31 sets the fourth deceleration limit as the deceleration limit. When both the impact condition and the failure condition are met, the deceleration limit to be set can be predetermined as either the third deceleration limit or the fourth deceleration limit.

[0068] In the example described above, if the conditions for high lift height, heavy object transport, and departure detection are met, the first deceleration limit is set as the deceleration limit. The control device 31 may set the lower of the first and second deceleration limits as the deceleration limit if both the conditions for high lift height, heavy object transport, departure detection and distance are met. If the second deceleration limit can be changed, the second deceleration limit may be lower than the first deceleration limit. In such cases, if both the conditions for high lift height, heavy object transport, departure detection and distance are met, the second deceleration limit may be set as the deceleration limit. That is, "the first deceleration limit is preferentially set as the deceleration limit" means that if the conditions for high lift height, heavy object transport, and departure detection are met and the first deceleration limit is lower than the second deceleration limit, the first deceleration limit is set as the deceleration limit. Furthermore, if the distance condition is not met, but the high lift height, heavy object transport, and departure judgment conditions, impact conditions, and failure conditions are met, the lowest value among the first deceleration limit, third deceleration limit, and fourth deceleration limit may be set as the deceleration limit. "The second deceleration limit is set preferentially as the deceleration limit" means that if the distance condition is met, the second deceleration limit is set as the deceleration limit. In other words, if the distance condition is met, the second deceleration limit is set as the deceleration limit regardless of whether the impact conditions and failure conditions are met.

[0069] [Operation of this embodiment] In cases where the distance condition is met, it may be desirable to increase the second deceleration limit to quickly stop the forklift 10. Increasing the second deceleration limit allows for deceleration at a larger rate, thus enabling the forklift 10 to stop quickly. On the other hand, when the high lifting height, heavy load transport, and driver departure detection conditions are met, it is not possible to increase the first deceleration limit to suppress the rapid deceleration of the forklift 10. If both the high lifting height, heavy load transport, driver departure detection conditions and the distance condition are met, and the second deceleration limit is set as the deceleration limit, there may be cases where deceleration at a large rate is undesirable.

[0070] The control device 31, when the conditions for high lift height, heavy object transport, and passenger departure are met, sets the first deceleration limit as the deceleration limit, prioritizing it over the second deceleration limit. This allows for a large deceleration using the second deceleration limit when the conditions for high lift height, heavy object transport, and passenger departure are not met but the distance condition is met, while allowing for a gentler deceleration using the first deceleration limit when the conditions for high lift height, heavy object transport, and passenger departure are met.

[0071] [Effects of this embodiment] (1) When the conditions for high lift height, heavy object transport, and departure from the seat are met, the control device 31 sets the first deceleration limit as the deceleration limit, prioritizing it over the second deceleration limit. This prevents the first deceleration limit and the second deceleration limit from interfering with each other.

[0072] (2) The conditions for determining high lifting height, heavy load handling, and departure from the forklift include the lifting height of the cargo handling device 20 being equal to or greater than a predetermined lifting height threshold. The higher the lifting height of the cargo handling device 20, the lower the conditions for high lifting height, heavy load handling, and departure from the forklift 10 tend to be. By ensuring that the conditions for high lifting height, heavy load handling, and departure from the forklift are met in this case, the first deceleration upper limit can be set preferentially when a gradual deceleration is required.

[0073] (3) If the second deceleration limit is higher than the accelerator-off deceleration limit, the control device 31 displays a warning on the display 82. If the distance condition is met, the control device 31 sets a vehicle speed limit and a deceleration limit. The control device 31 may also issue a warning. As a result, the driver of the forklift 10 releases the accelerator pedal 16. At this time, if the second deceleration limit is higher than the accelerator-off deceleration limit, the deceleration limit will be lowered when the accelerator pedal 16 is released. The driver may feel uncomfortable with the operation because the deceleration will be gradual despite the release of the accelerator pedal 16. By displaying a warning on the display 82 when the second deceleration limit is higher than the accelerator-off deceleration limit, it is possible to notify the driver that the setting of the second deceleration limit is not effective.

[0074] (4) When the distance condition is met, the control device 31 sets the second deceleration limit as the deceleration limit, giving priority over the third deceleration limit. This prevents the second deceleration limit and the third deceleration limit from interfering with each other.

[0075] (5) When the distance condition is met, the control device 31 sets the second deceleration limit as the deceleration limit, giving it priority over the fourth deceleration limit. This prevents the second deceleration limit and the fourth deceleration limit from interfering with each other.

[0076] [Example of changes] The embodiment can be implemented with the following modifications. The embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0077] ○The control device 31 does not need to impose speed limits or deceleration limits in the event of a battery failure 61. ○The control device 31 does not need to impose speed and deceleration limits on the telematics terminal 40 due to an impact.

[0078] ○The control device 31 may choose not to display a warning even if the second deceleration limit is changed to a value higher than the accelerator-off deceleration limit. The control device 31 may also provide an audible warning instead of a warning display.

[0079] ○The second deceleration limit may be unchangeable. ○The control device 31 may perform only one of the following: a deceleration limit based on the status of the cargo handling device 20, or a deceleration limit due to the driver leaving the seat.

[0080] ○When the control device 31 sets speed limits and deceleration limits based on the lifting height of the cargo handling device 20, the control device 31 may continuously lower the upper limit of the vehicle speed as the lifting height increases, or it may gradually lower the upper limit of the vehicle speed as the lifting height increases. The control device 31 may continuously lower the upper limit of the deceleration as the lifting height increases, or it may gradually lower the upper limit of the deceleration as the lifting height increases.

[0081] ○The first high-lift, heavy-object transport, and departure judgment condition may also be that the weight of the load L is equal to or greater than the weight threshold. The obstacle detection unit 71 may be equipped with a monocular camera, a ToF (Time of Flight) camera, a LIDAR (Laser Imaging Detection and Ranging), or a millimeter-wave radar instead of the stereo camera 72. The obstacle detection unit 71 may also be equipped with a combination of multiple sensors, such as the stereo camera 72 and a LIDAR.

[0082] ○The alarm unit 74 may be provided by a component other than the obstacle detection unit 71. ○The alarm unit 74 may be operated directly by the control device 31. ○The forklift 10 may have a vehicle speed that changes according to the amount of operation of the direction control unit 17. In this case, the upper limit of deceleration when the accelerator is off is the upper limit of deceleration when the direction control unit 17 is not being operated.

[0083] ○The industrial vehicle may be a towing tractor. In that case, the conditions for high lifting height, heavy load transport, and driver leaving the seat will be determined by whether or not the driver is away from the seat. The technical concepts that can be understood from the above embodiments and modified examples are described below.

[0084] [Aspect 1] An industrial vehicle comprising: a control device that decelerates the industrial vehicle at a deceleration of less than or equal to a set deceleration upper limit; and an obstacle detection unit that detects the relative distance between the industrial vehicle and an obstacle, wherein the control device performs a first deceleration limit which sets a first deceleration upper limit when the high lifting height, heavy load transport, and driver departure determination conditions are met, which are met when the industrial vehicle is in a high lifting height state, the load weight is above a threshold state, or driver departure is detected; a second deceleration limit which sets a second deceleration upper limit when the distance condition is met, which is met when the relative distance between the industrial vehicle and the obstacle is less than a predetermined distance threshold; and priority control which, when the high lifting height, heavy load transport, and driver departure determination conditions are met, sets the first deceleration upper limit as the deceleration upper limit with priority over the second deceleration upper limit.

[0085] [Aspect 2] The industrial vehicle is equipped with a cargo handling device, and the high lifting height, heavy object transport, and passenger departure determination conditions include the lifting height of the cargo handling device being equal to or greater than a predetermined lifting height threshold, as described in [Aspect 1].

[0086] [Aspect 3] The industrial vehicle according to [Aspect 1] or [Aspect 2], comprising a display and an operating unit configured to change at least one of the upper limit of deceleration when the accelerator is released and the second upper limit of deceleration when the accelerator is released by operation by the user, wherein the control device displays a warning on the display when the second upper limit of deceleration is higher than the upper limit of deceleration when the accelerator is released.

[0087] [Aspect 4] An industrial vehicle according to any one of [Aspect 1] to [Aspect 3], wherein the control device performs a third deceleration limit, setting the third deceleration limit as the deceleration limit when an impact exceeding a predetermined impact threshold is applied to the telematics terminal, and the priority control, when the distance condition is met, sets the second deceleration limit as the deceleration limit with priority over the third deceleration limit.

[0088] [Aspect 5] An industrial vehicle according to any one of [Aspect 1] to [Aspect 4], wherein the control device performs a fourth deceleration limit by setting the fourth deceleration limit as the deceleration limit when the battery fails, and the priority control sets the second deceleration limit as the deceleration limit with priority over the fourth deceleration limit when the distance condition is met. [Explanation of Symbols]

[0089] 10... Forklift, an industrial vehicle; 20... Cargo handling equipment; 31... Control device; 40... Telematics terminal; 61... Battery; 71... Obstacle detection unit; 82... Display unit; 83... Operation unit.

Claims

1. Industrial vehicles, A control device that decelerates the industrial vehicle at a deceleration rate below a set deceleration upper limit, The system includes an obstacle detection unit that detects the relative distance between the industrial vehicle and the obstacle, The control device is A first deceleration limit is set when the high lift height, heavy load transport, and driver departure detection conditions are met, which are met when the industrial vehicle is in a high lift height state, the load weight is above a threshold state, or the driver is detected leaving the vehicle. A second deceleration limit is set when a distance condition is met that is met when the relative distance between the industrial vehicle and the obstacle is less than a predetermined distance threshold, and An industrial vehicle that, when the aforementioned conditions for high lift height, heavy object transport, and passenger departure are met, performs priority control by setting the first deceleration limit as the deceleration limit, with higher priority than the second deceleration limit.

2. The aforementioned industrial vehicle is equipped with a cargo handling device, The industrial vehicle according to claim 1, wherein the aforementioned high lifting height, heavy object transport, and passenger departure determination conditions include the lifting height of the cargo handling device being equal to or greater than a predetermined lifting height threshold.

3. The aforementioned industrial vehicle is Display unit, The system includes an operating unit configured to allow the user to change at least one of the upper limit of deceleration when the accelerator is released and the second upper limit of deceleration, If the second deceleration limit is higher than the deceleration limit when the accelerator is released, the control device displays a warning on the display, as described in claim 1 or claim 2.

4. The control device performs a third deceleration limit, which sets a third deceleration upper limit, when an impact exceeding a predetermined impact threshold is applied to the telematics terminal. The industrial vehicle according to claim 1 or 2, wherein the priority control includes setting the second deceleration limit as the deceleration limit with priority over the third deceleration limit when the distance condition is met.

5. The control device performs a fourth deceleration limit, which sets a fourth deceleration upper limit, in the event of a battery failure. The industrial vehicle according to claim 1 or 2, wherein the priority control includes setting the second deceleration limit as the deceleration limit with priority over the fourth deceleration limit when the distance condition is met.

Images