Work machine control system, work machine, and work machine control method

Abstract

To provide a work machine capable of appropriately detecting a surrounding object and a work machine control method.SOLUTION: This work machine control system comprises: an object detection device 70 that detects an object around the work machine; a vehicle speed sensor 62 that detects a vehicle speed of the work machine; a setting unit 93 that sets a first detection range and a second detection range for detecting an object around the work machine; a switching unit 92 that switches between the first detection range and the second detection range in accordance with the vehicle speed detected by the vehicle speed sensor 62; and a determination unit 95 that determines whether an object has been detected in the first detection range or the second detection range switched by the switching unit 92.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a work machine and a method for controlling a work machine. [Background technology]

[0002] For example, it is known that a work machine including a forklift is provided with a detection device that detects whether or not an object including a person is present in the vicinity (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-194481 A Summary of the Invention [Problem to be solved by the invention]

[0004] A work machine travels in a place where various objects are present in the vicinity, such as a warehouse or a factory. If a detection device installed on the work machine detects all objects that enter a detectable range and outputs an alarm, the alarm will be issued frequently.

[0005] An object of aspects of the present disclosure is to provide a work machine and a control method for a work machine that are capable of appropriately detecting surrounding objects. [Means for solving the problem]

[0006] According to an aspect of the present disclosure, there is provided a work machine including an object detection unit that detects objects in the vicinity of a work machine, a vehicle speed detection unit that detects the vehicle speed of the work machine, a setting unit that sets a first detection range and a second detection range for detecting the object in the vicinity of the work machine, a switching unit that switches between the first detection range and the second detection range in accordance with the vehicle speed detected by the vehicle speed detection unit, and a determination unit that determines whether the object has been detected in the first detection range or the second detection range switched by the switching unit.

[0007] According to an aspect of the present disclosure, there is provided a method for controlling a work machine including detecting an object in the vicinity of a work machine by an object detection unit, detecting a vehicle speed of the work machine by a vehicle speed detection unit, setting a first detection range and a second detection range for detecting the object in the vicinity of the work machine, switching between the first detection range and the second detection range depending on the vehicle speed detected by the vehicle speed detection unit, and determining whether the object has been detected in the switched first detection range or the switched second detection range. Effect of the Invention

[0008] According to an aspect of the present disclosure, a work machine and a control method for a work machine that are capable of appropriately detecting surrounding objects are provided. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing a forklift according to this embodiment as viewed diagonally from above and rear on the left side. [Diagram 2] FIG. 2 is a functional block diagram showing an example of a control system for a forklift according to this embodiment. [Diagram 3] FIG. 3 is a schematic diagram showing an example of the first range. [Figure 4] FIG. 4 is a schematic diagram showing an example of the second range. [Diagram 5] FIG. 5 is a schematic diagram showing another example of the second range. [Figure 6] FIG. 6 is a schematic diagram showing another example of the second range. [Figure 7] FIG. 7 is a schematic diagram showing another example of the second range. [Figure 8] FIG. 8 is a diagram illustrating an example of the warning levels. [Figure 9] FIG. 9 is a flowchart illustrating an example of processing by the object detection system. [Figure 10] FIG. 10 is a flowchart showing an example of an object detection process in a first range of the object detection system. [Figure 11] FIG. 11 is a flowchart showing an example of an object detection process in a second range of the object detection system. [Figure 12] FIG. 12 is a block diagram showing an example of a computer system according to this embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings, but the present disclosure is not limited thereto. The components of each embodiment described below can be appropriately combined. In addition, some components may not be used.

[0011] In this embodiment, a forklift 1 driven by power from a battery or power obtained from a generator driven by an engine or the like will be described as an example of a work machine, but the work machine is not limited to this. For example, the work machine may be a wheel loader driven by power from a battery or power obtained from a generator driven by an engine or the like. Furthermore, the work machine is not limited to one driven by electricity, and may be a forklift driven by hydraulics, etc.

[0012] 1 is a perspective view of a forklift 1 according to this embodiment, as viewed from diagonally above and to the left rear. In the following description of the forklift 1, the side on which the forks 13 are provided is the front, and the side on which the counterweight 20 is provided is the rear. If the work machine is not a forklift, the side from the driver's seat 34 toward a handle 36 serving as an operating device is the front, and the side from the handle 36 toward the driver's seat 34 is the rear. The operating device includes the handle 36 used to steer the work machine, as well as an operating lever for operating the work machine in the case of a hydraulic excavator, a wheel loader, or the like.

[0013] In this embodiment, left and right refer to left and right relative to the front. The left and right direction is the width direction of the vehicle body 10 as the main body of the work machine. The upper side is the side that is perpendicular to a plane (ground plane) that contacts at least three of the front wheels 11 and the rear wheels 12 and faces the rotation center axis of the front wheels 11 or the rear wheels 12 from the ground plane. The lower side is the side that faces the ground plane from the rotation center axis of the front wheels 11 or the rear wheels 12. An axis that faces the front-rear direction of the vehicle body 10 and passes through the center of the width of the vehicle body 10 is called the front-rear axis, and an axis that is perpendicular to the front-rear axis, parallel to the installation plane, and faces the left-right direction of the vehicle body 10 is called the left-right axis. An axis that faces the up-down direction of the vehicle body 10 is called the up-down axis. The up-down axis is perpendicular to both the front-rear axis and the left-right axis. In the following, a plan view refers to a state seen from above.

[0014] <Overall configuration of forklift> The forklift 1 has front wheels 11 at the left and right ends of the front of a vehicle body 10, and rear wheels 12 at the left and right ends of the rear of the vehicle body 10. A fork 13 for loading and unloading or moving cargo is installed at the front of the vehicle body 10. The fork 13 is supported by a mast 14 installed along the vertical direction. The fork 13 moves up and down along the mast 14 by driving a mast cylinder 15 installed between the fork 13 and the mast 14. The lower end of the mast 14 is attached to the vehicle body 10 so as to be rotatable around a left-right axis. The mast 14 can be tilted forward or backward with respect to the vehicle body 10 by driving a tilt cylinder (not shown) installed between the mast 14 and the vehicle body 10.

[0015] A counterweight 20 is provided at the rear end of the vehicle body 10. The forklift 1 is a counterbalanced forklift, but is not limited to this. The counterweight 20 is a weight for balancing the forks 13 when they support a load.

[0016] The forklift 1 is equipped with an accelerator pedal 37, a brake pedal 38, and a travel direction change lever 39. The accelerator pedal 37 is an operation member for controlling the output and rotation direction of a traveling electric motor (not shown). The brake pedal 38 is an operation member for stopping the forklift 1. The travel direction change lever 39 is an operation member for changing the travel direction of the forklift 1 to either forward or backward.

[0017] The forklift 1 has a display panel 52 installed in front of the handle 36 as a display device. The display panel 52 has an input section for making various settings for the forklift 1 and a display section for displaying information related to the status of the forklift 1. The operator of the forklift 1 makes various settings for the forklift 1 via the display panel 52. The information related to the status of the forklift 1 is, for example, an alarm indicating that an object has been detected in the vicinity of the forklift 1. The object includes, for example, workers, other work machines, obstacles, etc., in the vicinity of the forklift 1.

[0018] <Overall control system for forklift> Next, an example of a control system of the forklift 1 according to this embodiment will be described. As shown in Fig. 2, the control system of the forklift 1 includes a vehicle control device 69 that controls the forklift 1. Fig. 2 is a functional block diagram showing an example of the control system of the forklift 1 according to this embodiment.

[0019] The vehicle control device 69 includes a numerical calculation device (processor) such as a CPU (Central Processing Unit). The vehicle control device 69 can control the traveling state of the forklift 1. The vehicle control device 69 acquires various data indicating the traveling state of the forklift 1. More specifically, the vehicle control device 69 acquires, for example, data indicating the tire turning angle of the forklift 1, data indicating the vehicle speed, data indicating the traveling direction, and data indicating the state of a parking brake (not shown).

[0020] Such a vehicle control device 69 functions as a part of the vehicle body data acquisition device 60 that detects data indicating state quantities of the vehicle body 10 of the forklift 1. The vehicle body data acquisition device 60 will be described later.

[0021] <Object detection system> Next, an object detection system 300 according to this embodiment will be described. The forklift 1 is equipped with the object detection system 300 capable of detecting objects around the forklift 1. In this embodiment, the forklift 1 will be described as being equipped with the object detection system 300 capable of detecting objects behind the forklift 1, as an example. The forklift 1 may also be equipped with the object detection system 300 capable of detecting objects in front of the forklift 1.

[0022] In this embodiment, the object detection system 300 detects an object behind the forklift 1 in the longitudinal direction, but does not detect an object in front of the forklift 1. The forks 13 are installed in front of the forklift 1. Therefore, the object detection device 70 is highly likely to detect a load placed on the forks 13, and may output a false alarm. In addition, the operator sitting in the driver's seat can visually check the front. For these reasons, the object detection system 300 is described as detecting an object behind the forklift 1. Note that when the object detection system 300 detects an object in front of the forklift 1, the object detection device 70 may be installed in a position where the load placed on the forks 13 is difficult to detect.

[0023] The object detection system 300 includes a vehicle body data acquisition device 60 that acquires vehicle body data of the forklift 1, an object detection device (object detection section) 70 that detects objects behind the forklift 1, an alarm device (alarm section) 80 that outputs an alarm, and a control device 90 that controls the forklift 1. The detection results of the vehicle body data acquisition device 60 and the object detection device 70 are output to the control device 90. The control device 90 outputs an alarm from the alarm device 80 based on these detection results.

[0024] <Vehicle data acquisition device> The vehicle body data acquisition device 60 includes a vehicle control device 69 of the forklift 1, a steering angle sensor (steering angle detection unit) 61 that detects the tire steering angle (steering angle) of the forklift 1, and a vehicle speed sensor (vehicle speed detection unit) 62 that detects the vehicle speed of the forklift 1.

[0025] The turning angle sensor 61 detects sensor data that allows the calculation of the turning angle of the tires of the forklift 1. The turning angle sensor 61 includes, for example, a steering sensor that detects the steering angle of a steering device (not shown) of the forklift 1. For example, a rotary encoder can be used as the steering sensor. The turning angle sensor 61 may include a rotation amount sensor that detects the amount of rotation or steering angle of a travel direction operation unit (not shown) of the forklift 1. The turning angle sensor 61 outputs the detected sensor data to the vehicle control device 69 as a detection result. The vehicle control device 69 calculates the turning angle from the detection result of the turning angle sensor 61.

[0026] The vehicle speed sensor 62 detects the vehicle speed of the forklift 1. More specifically, the vehicle speed sensor 62 detects sensor data from which the vehicle speed of the forklift 1 can be calculated. The vehicle speed sensor 62 includes a rotation speed sensor that detects the rotation speed of the front wheels 11 or the rear wheels 12. The vehicle speed sensor 62 outputs the detected sensor data as a detection result to the vehicle control device 69. The vehicle control device 69 calculates the vehicle speed from the detection result of the vehicle speed sensor 62.

[0027] The travel direction sensor 63 detects the travel direction of the forklift 1. More specifically, the travel direction sensor 63 detects data indicating the operation state of a forward / reverse lever that switches the forklift 1 between forward or reverse and neutral. The travel direction sensor 63 detects the position of the forward / reverse lever that indicates the travel direction. When the operation position of the forward / reverse lever is forward, the travel direction sensor 63 detects data indicating that the travel direction is forward. When the operation position of the forward / reverse lever is reverse, the travel direction sensor 63 detects data indicating that the travel direction is reverse. When the operation position of the forward / reverse lever is neutral, the travel direction sensor 63 detects data indicating that the travel direction is neutral. The travel direction sensor 63 outputs the detection result to the vehicle control device 69.

[0028] The parking brake sensor 64 detects the state of the parking brake of the forklift 1. The parking brake sensor 64 detects whether the parking brake is applied or released based on the amount of depression of the parking brake. The parking brake sensor 64 outputs the detection result to the vehicle control device 69.

[0029] <Object detection device> The object detection device 70 detects objects around the forklift 1. In this embodiment, the object detection device 70 detects objects behind the forklift 1 in a non-contact manner. The object detection device 70 includes a radar device such as a millimeter wave radar device. The radar device can detect the presence or absence of an object in front of the radar device by, for example, transmitting radio waves or ultrasonic waves and receiving the radio waves or ultrasonic waves reflected by the object. The radar device can detect not only the presence or absence of an object, but also the relative distance and direction as the relative position to the object, and the relative speed to the object. The object detection device 70 may be composed of at least one of a laser scanner and a three-dimensional distance sensor. A plurality of object detection devices 70 may be installed.

[0030] The object detection device 70 is installed at the rear of the forklift 1. In this embodiment, the object detection device 70 is installed on the rear pillar 16 as shown in Fig. 1. However, the object detection device 70 may be installed in another position as long as it can detect an object behind the forklift 1.

[0031] In this embodiment, the object detection device 70 has a detection area behind the forklift 1. More specifically, the object detection device 70 has a detection area that spreads radially in both the up-down and left-right directions behind the forklift 1. The object detection device 70 is capable of detecting an object present in the detection area. The object detection device 70 is capable of detecting a relative distance and direction indicating the relative position between the forklift 1 and an object present in the detection area, and a relative speed between the object and the object.

[0032] The length of the detection area of ​​the object detection device 70 in the front-rear direction of the forklift 1 is Xa [m]. The length Xa [m] is the distance between an emission part (not shown) of the object detection device 70 and the tip of the detection area. The length Xa [m] is, for example, about 5 m.

[0033] In this embodiment, the object detection device 70 includes a left radar (object detection unit) 70L and a right radar (object detection unit) 70R that are installed as a pair. The left radar 70L is installed on the rear left side of the forklift 1. The left radar 70L can detect objects on the rear left side of the forklift 1. The right radar 70R is installed on the rear right side of the forklift 1. The right radar 70R can detect objects on the rear right side of the forklift 1. The left radar 70L and the right radar 70R may be installed on the rear of the forklift 1 so that the detection area of ​​the left radar 70L and the detection area of ​​the right radar 70R partially overlap, or may be installed so that the detection area of ​​the left radar 70L and the detection area of ​​the right radar 70R do not overlap. Objects present behind the forklift 1 are detected by the left radar 70L and the right radar 70R.

[0034] <Alarm device> The warning device 80 outputs a warning when a determination unit 95 of the control device 90 described later determines that the warning level is greater than 0 and that the forklift 1 can move backward. The warning device 80 may output a warning according to the warning level determined by the determination unit 95. The warning device 80 executes a warning generation process to alert the operator. The warning device 80 uses, for example, a speaker or a lamp to emit a sound or light to notify the operator that an object is present behind the vehicle, thereby alerting the operator. The warning device 80 may display on the display panel 52. A plurality of warning devices 80 may be installed.

[0035] The alarm device 80 is installed, for example, near the driver's seat of the forklift 1. In this embodiment, the alarm device 80 is installed on the rear pillar 16 together with the object detection device 70 as shown in Fig. 2. The alarm device 80 may be installed in another position as long as it can notify an alarm to the operator in the driver's seat or near the forklift 1.

[0036] A plurality of alarm devices 80 may be installed around the driver's seat of the forklift 1. In this embodiment, the alarm device 80 includes a left alarm device (alarm unit) 80L and a right alarm device (alarm unit) 80R installed as a pair. The left alarm device 80L is installed on the rear left side of the forklift 1. The left alarm device 80L is installed in front of the left radar 70L. The right alarm device 80R is installed on the rear right side of the forklift 1. The right alarm device 80R is installed in front of the right radar 70R. The left alarm device 80L and the right alarm device 80R may simultaneously output an alarm sound or turn on. Alternatively, an alarm may be output from the left alarm device 80L or the right alarm device 80R corresponding to the detection direction of the object. More specifically, an alarm may be output from the left alarm device 80L only when an object is detected by the left radar 70L or when an object is detected to the left of the front-rear axis of the forklift 1. Only when an object is detected by the right radar 70R or when an object is detected to the right of the front-rear axis of the forklift 1, may the right warning device 80R output a warning.

[0037] <Control system for object detection system> The object detection device 70 and the alarm device 80 are connected to the control device 90. The control device 90 includes a numerical calculation device (processor) such as a CPU. The control device 90 detects objects around the forklift 1 based on the detection result of the object detection device 70, and controls the output of an alarm. The control device 90 includes a vehicle body data acquisition unit 91, a switching unit 92, a setting unit 93, an object data acquisition unit 94, a determination unit 95, an alarm control unit 96, and a memory unit 99.

[0038] The vehicle body data acquisition unit 91 acquires vehicle body data of the forklift 1 from the vehicle control device 69. The vehicle body data acquisition unit 91 includes a turning angle acquisition unit 911 and a vehicle speed acquisition unit 912. The vehicle body data acquisition unit 91 outputs the acquired vehicle body data to the switching unit 92, the setting unit 93, and the determination unit 95.

[0039] The turning angle acquisition unit 911 acquires the tire turning angle of the rear wheels 12 of the forklift 1 from the vehicle control device 69. The acquired tire turning angle of the forklift 1 is included in the vehicle body data and is output to the switching unit 92, the setting unit 93, and the determination unit 95.

[0040] The vehicle speed acquisition unit 912 acquires the vehicle speed of the forklift 1 from the vehicle control device 69. The acquired vehicle speed of the forklift 1 is output to the switching unit 92, the setting unit 93, and the determination unit 95 together with being included in the vehicle body data.

[0041] The switching unit 92 switches between a first detection range (hereinafter referred to as the "first range") A1 and a second detection range (hereinafter referred to as the "second range") A2, which are ranges in which objects are detected around the forklift 1, depending on the vehicle speed of the forklift 1. In this embodiment, when the forklift 1 is stopped, the switching unit 92 switches the range in which objects are detected to the first range A1. When the forklift 1 is not stopped, the switching unit 92 switches the range in which objects are detected to the second range A2. The switching between the first range A1 and the second range A2 by the switching unit 92 is not limited to the above conditions.

[0042] The switching unit 92 may switch the object detection range to the first range A1 when the vehicle speed of the forklift 1 is equal to or lower than the second vehicle speed threshold. More specifically, the switching unit 92 may switch the object detection range to the first range A1 when the forward / reverse lever of the forklift 1 is in the "reverse" position, the parking brake is released, and the vehicle speed of the forklift 1 is equal to or lower than the second vehicle speed threshold. The switching unit 92 may also switch the object detection range to the second range A2 when the vehicle speed of the forklift 1 is higher than the second vehicle speed threshold. More specifically, the switching unit 92 may switch the object detection range to the second range A2 when the forklift 1 is moving backward, in other words, when the forward / reverse lever of the forklift 1 is in the "reverse" position, the parking brake is released, and the vehicle speed of the forklift 1 is higher than the second vehicle speed threshold.

[0043] The setting unit 93 sets a first range A1 and a second range A2 for detecting objects around the forklift 1. The first range A1 and the second range A2 are ranges included in the detection area of ​​the object detection device 70. The setting unit 93 sets the width of the forklift 1 in the width direction and the length of the forklift 1 in the traveling direction for the first range A1 and the second range A2. More specifically, the setting unit 93 sets the first range A1 as a range of a fixed shape including a range of a fixed distance (predetermined distance) from the forklift 1. The setting unit 93 sets the second range A2 as a range whose shape changes according to the vehicle speed of the forklift 1. The setting unit 93 may set the second range A2 as a range whose shape changes according to the vehicle speed and the tire turning angle of the forklift 1. The setting unit 93 stores the set first range A1 and second range A2 in the storage unit 99.

[0044] The setting unit 93 may set the first range A1 and the second range A2 into a plurality of ranges into which the alarm level can be classified. The setting unit 93 sets the first range A1 into a plurality of portions according to the alarm level. For example, the setting unit 93 sets the first range A1 into two portions, a first portion A11 and a second portion A12. The setting unit 93 sets the second range A2 into a plurality of portions according to the alarm level. For example, the setting unit 93 sets the second range A2 into two portions, a first portion A21 and a second portion A22.

[0045] <First range A1> 3 is a schematic diagram showing an example of the first area A1. The outer shape of the first area A1 is rectangular. The first area A1 includes a width W in the width direction of the forklift 1 and a length L in the reverse direction, which is the traveling direction of the forklift 1. The width W includes the vehicle width Wr of the forklift 1.

[0046] The first range A1 includes a first portion A11 and a second portion A12 that is farther from the forklift 1 than the first portion A11 in the reverse direction which is the traveling direction.

[0047] The first portion A11 has a length L1 in the rearward direction from the rear end of the forklift 1. The second portion A12 has a length L2 in the rearward direction from the rear end of the first portion A11. Both the first portion A11 and the second portion A12 have a width W. The length L1, the length L2, and the width W are fixed values.

[0048] In this embodiment, the first portion A11 is defined as a danger area with an alarm level of Level 2 (first level). The second portion A12 is defined as a warning area with an alarm level of Level 1 (second level) lower than Level 2. The areas other than the first portion A11 and the second portion A12 are defined as an alarm level of Level 0 (third level) lower than Level 1.

[0049] In this manner, the setting unit 93 sets the first range A1 of a fixed shape based on the length L1, the length L2, and the width W stored in the memory unit 99. The setting unit 93 may set the first detection range A1 to include a first portion A11 having an alarm level of Level 2, and a second portion A12 having an alarm level of Level 1 that is farther from the forklift 1 than the first portion A11 in the forward direction, which is the traveling direction of the forklift 1, and is lower than Level 2.

[0050] <Second range A2> FIG. 4 is a schematic diagram showing an example of the second range A2. The outer shape of the second range A2 changes to a rectangular shape or an arc shape so as to follow a predicted course according to the tire turning angle of the forklift 1. FIG. 4 shows, as an example, a state in which the second range A2 is an arc shape. The second range A2 shown in FIG. 4 is an arc shape of radius R with the center of rotation C corresponding to the tire turning angle of the forklift 1. The second range A2 includes a range of width W in the width direction of the forklift 1 and length L in the traveling direction of the forklift 1. The width W includes the vehicle width Wr of the forklift 1. The length L changes according to the vehicle speed of the forklift 1.

[0051] The second range A2 includes a first portion A21 and a second portion A22 that is farther from the forklift 1 than the first portion A21 in the reverse direction which is the traveling direction.

[0052] The first portion A21 and the second portion A22 each have a width W. The first portion A21 has a length L1 in the traveling direction from the rear end of the forklift 1. In other words, the length L1 is from a reference point P0 located on the front-rear axis of the rear end of the forklift 1 to a point P1 at the tip of the first portion A21. The second portion A22 has a length L2 in the traveling direction from the rear end of the first portion A21. In other words, the length L2 is from the point P1 to a point P2 at the tip of the second portion A22. The reference points P0, P1, and P2 are located on an arc of radius R from the rotation center C of the tire turning angle of the forklift 1. The lengths L1 and L2 change depending on the vehicle speed of the forklift 1.

[0053] The setting unit 93 changes the length L of the second range A2 based on the vehicle speed of the forklift 1 acquired by the vehicle speed acquisition unit 912. More specifically, when the vehicle speed of the forklift 1 is low, the setting unit 93 shortens the length L of the second range A2. When the vehicle speed of the forklift 1 is high, the setting unit 93 lengthens the length L of the second range A2. Fig. 5 is a schematic diagram showing another example of the second range A2. Fig. 5 shows an example in which the vehicle speed of the forklift 1 is lower than that in Fig. 4 and the length L of the second range A2 is shorter.

[0054] When changing the length L of the second range A2, the setting unit 93 changes the position of the end of the second range A2 in the traveling direction of the forklift 1. For example, when shortening the length L of the second range A2, the setting unit 93 changes the relative position between the end of the second range A2 and the forklift 1 along the predicted course so that the end of the second range A2 approaches the forklift 1. When length L of the second range A2 is increased, the setting unit 93 changes the relative position between the end of the second range A2 and the forklift 1 along the predicted course so that the end of the second range A2 moves away from the forklift 1.

[0055] The setting unit 93 deforms the shape of the second area A2 based on the tire turning angle of the forklift 1 acquired by the turning angle acquisition unit 911. For example, as shown in FIG. 4, when the tire turning angle of the forklift 1 indicates that the traveling direction of the forklift 1 changes to the right and turns right, the setting unit 93 sets the shape of the second area A2 by bending it to the right so as to be aligned with the traveling direction of the forklift 1. The setting unit 93 sets the shape of the second area A2 so that the tip of the second area A2 moves to the right with respect to the front-rear direction of the forklift 1. FIG. 6 is a schematic diagram showing another example of the second area A2. For example, as shown in FIG. 6, when the tire turning angle of the forklift 1 indicates that the traveling direction of the forklift 1 changes to the left and turns left, the setting unit 93 sets the shape of the second area A2 by bending it to the left so as to be aligned with the traveling direction of the forklift 1. The setting unit 93 sets the shape of the second area A2 so that the tip of the second area A2 moves to the left with respect to the front-rear direction of the forklift 1.

[0056] The setting unit 93 changes the shape of the second area A2 based on the tire turning angle of the forklift 1 acquired by the turning angle acquisition unit 911. More specifically, when the tire turning angle of the forklift 1 is large, the setting unit 93 makes the curve of the second area A2 steeper. When the tire turning angle of the forklift 1 is small, the setting unit 93 makes the curve of the second area A2 gentler.

[0057] Here, the setting unit 93 sets the Level 2 danger area as the first portion A21 of the second range A2 at each vehicle speed. The setting unit 93 sets the Level 1 warning area as the second portion A22 of the second range A2 at each vehicle speed. The setting unit 93 sets the area other than the first portion A21 and the second portion A22 as a Level 0 area at each vehicle speed. The length L of the second range A2 may be divided at a predetermined ratio to set the first portion A21 and the second portion A22. Also, the division ratio may be changed according to the vehicle speed.

[0058] The length L of the second range A2 approaches zero as the relative speed decreases, in other words, as the vehicle speed of the forklift 1 approaches zero. Therefore, the setting unit 93 may set the first portion A21 of the second range A2 as a fixed range when the vehicle speed of the forklift 1 is equal to or lower than the first vehicle speed threshold. The first vehicle speed threshold may be set to a value close to zero, such as immediately after the forklift 1 starts moving backward. In this embodiment, when the vehicle speed is equal to or lower than the first vehicle speed threshold, the setting unit 93 sets the second range A2 with the length L1 of the first portion A21 as the fixed length Xb. When the vehicle speed exceeds the first vehicle speed threshold, the fixed length Xb may be lengthened according to the vehicle speed. FIG. 7 is a schematic diagram showing another example of the second range A2. In this case, as shown in FIG. 7, the second range A2 has only the first portion A21. The fixed range may be set to each of the first portion A21 and the second portion A22. The first vehicle speed threshold may be the same value as the second vehicle speed threshold.

[0059] In this manner, the setting unit 93 sets the second range A2 changed to a rectangular or arc shape so as to follow a path predicted according to the tire turning angle of the forklift 1. Then, the setting unit 93 changes the length L of the second range A2 according to the vehicle speed of the forklift 1. The setting unit 93 may set the second detection range A2 to include a first portion A21 having an alarm level of Level 2, and a second portion A22 having an alarm level of Level 1 that is farther from the forklift 1 than the first portion A21 in the forward direction, which is the traveling direction of the forklift 1, and is lower than Level 2.

[0060] The object data acquisition unit 94 acquires object detection results as object data from the object detection device 70. The object data acquired by the object data acquisition unit 94 includes all detection results within the detection range of the object detection device 70.

[0061] The determination unit 95 determines whether or not an object has been detected around the forklift 1, based on the object data acquired by the object data acquisition unit 94. The determination unit 95 determines whether or not an object has been detected in the first range A1 or the second range A2, which is the range switched by the switching unit 92 to detect an object around the forklift 1.

[0062] More specifically, when the vehicle body data of the forklift 1 indicates that the forklift 1 is stopped, the determination unit 95 determines whether or not an object is present in the first range A1 based on the relative position and relative speed of the object data. When the relative position and relative speed of the object data indicate that an object is present in the first range A1, the determination unit 95 determines that an object has been detected in the vicinity of the forklift 1.

[0063] For example, when the vehicle body data of the forklift 1 indicates that the forklift 1 is not stopped, the determination unit 95 determines whether or not an object exists in the second range A2 based on the relative position and relative speed of the object data. When the relative position and relative speed of the object data indicate that an object exists in the second range A2, the determination unit 95 determines that an object has been detected in the vicinity of the forklift 1. Note that the determination unit 95 may be configured to determine whether or not an object exists in the second range A2 when the vehicle speed included in the vehicle body data indicates that it is equal to or higher than a second vehicle speed threshold value.

[0064] When the determination unit 95 determines that an object has been detected in the vicinity of the forklift 1, the determination unit 95 may further determine the warning level. The determination unit 95 determines the warning level according to the position where the object has been detected, dividing it into the highest level 2, the next highest level 1, and the lowest level 0. The determination unit 95 determines the warning level according to whether the object has been detected in the first portion A11 or the first portion A21 or the second portion A12 or the second portion A22. More specifically, when the determination unit 95 determines that the object exists in the first portion A11 or the first portion A21 based on the detection result of the object detection device 70, the determination unit 95 determines that the warning level is level 2. When the determination unit 95 determines that the object exists in the second portion A12 or the second portion A22 based on the detection result of the object detection device 70, the determination unit 95 determines that the warning level is level 1. If the judgment unit 95 does not determine, based on the detection result of the object detection device 70, that an object is present in the first part A11, the first part A21, the second part A12 or the second part A22, it determines that the warning level is level 0.

[0065] The determination unit 95 may cancel the object detection process, in other words, determine not to output an alarm, when the vehicle speed of the forklift 1 is equal to or greater than the third vehicle speed threshold. The third vehicle speed threshold is a value greater than the first vehicle speed threshold and the second vehicle speed threshold. This is because when the vehicle speed is equal to or greater than the third vehicle speed threshold, the forklift 1 travels a longer distance from when an object is detected until when an alarm is output, and there is a risk that an alarm will not be output at an appropriate time. The determination unit 95 may perform object detection process within the detection area of ​​the object detection device 70 even if the vehicle speed of the forklift 1 is equal to or greater than the third vehicle speed threshold.

[0066] The determination unit 95 may cancel the object detection process, in other words, determine not to output an alarm, when the tire turning angle of the forklift 1 is equal to or greater than the turning angle threshold. The turning angle threshold is, for example, a value when the forklift 1 makes a U-turn or changes direction suddenly. This is because, when the tire turning angle is equal to or greater than the turning angle threshold, the second range A2 falls outside the detection range of the object detection device 70. The determination unit 95 may perform the object detection process even if the tire turning angle of the forklift 1 is equal to or greater than the turning angle threshold, as long as the predicted path of the forklift 1 is within the detection area of ​​the object detection device 70.

[0067] When the determination unit 95 determines that the alarm level is greater than 0 and that the forklift 1 can move backward, the alarm control unit 96 controls the alarm device 80 to output an alarm. More specifically, the alarm control unit 96 outputs a control signal to output a sound through a speaker or to emit a light through an alarm lamp in order to alert the operator. The alarm control unit 96 may output an alarm image through the display panel 52 in order to alert the operator. In this embodiment, the alarm control unit 96 may control to output an alarm according to the alarm level determined by the determination unit 95.

[0068] The alarm patterns output for each alarm level will be described with reference to FIG. 8. FIG. 8 is a diagram for explaining an example of an alarm level. When the alarm level is level 2, a continuous buzzer sound, for example, "beep," is output from the speaker of the alarm device 80, and the alarm lamp of the alarm device 80 flashes at 4 [Hz]. When the alarm level is level 1, an intermittent buzzer sound, for example, "beep beep," is output from the speaker of the alarm device 80, and the alarm lamp of the alarm device 80 flashes at 2 [Hz]. When the alarm level is level 0, the buzzer sound is stopped and the alarm lamp is turned off. In other words, when the alarm level is level 0, no alarm is output.

[0069] When the determination unit 95 determines that the alarm level is greater than 0 and that the forklift 1 can move backward, the alarm control unit 96 may control the left alarm device 80L or the right alarm device 80R to output an alarm corresponding to the direction in which the object was detected. More specifically, the alarm control unit 96 may control the left alarm device 80L to output an alarm only when an object is detected by the left radar 70L or when an object is detected to the left of the front-rear axis of the forklift 1. The alarm control unit 96 may control the right alarm device 80R to output an alarm only when an object is detected by the right radar 70R or when an object is detected to the right of the front-rear axis of the forklift 1.

[0070] The storage unit 99 includes at least one of a random access memory (RAM), a read only memory (ROM), a flash memory, and a hard disk drive.

[0071] <Object detection system processing> When the forklift 1 is in operation, in other words, when the key switch of the forklift 1 is turned ON, the object detection system 300 is activated. While the object detection system 300 is activated, the vehicle body data acquisition device 60 detects the traveling state of the forklift 1, and the object detection device 70 detects objects around the forklift 1. The detection results of the vehicle body data acquisition device 60 and the object detection device 70 are output to the control device 90. The control device 90 acquires vehicle body data of the forklift 1 from the vehicle body data acquisition device 60. The control device 90 acquires the detection results from the object detection device 70.

[0072] A method for controlling the forklift 1, more specifically, processing in the control device 90 of the object detection system 300 will be described with reference to Fig. 9 to Fig. 11. Fig. 9 is a flowchart showing an example of processing in the object detection system 300. Fig. 10 is a flowchart showing an example of object detection processing in the first range A1 of the object detection system 300. Fig. 11 is a flowchart showing an example of object detection processing in the second range A2 of the object detection system 300.

[0073] First, a method in which the control device 90 of the object detection system 300 switches between the first range A1 and the second range A2 depending on the traveling state of the forklift 1 will be described with reference to FIG.

[0074] The control device 90 acquires the tire turning angle of the forklift 1 from the vehicle body data of the forklift 1 acquired by the vehicle body data acquisition unit 91 through the turning angle acquisition unit 911 (step S11). The control device 90 proceeds to step S12.

[0075] The control device 90 causes the vehicle speed acquisition unit 912 to acquire the vehicle speed of the forklift 1 from the vehicle body data of the forklift 1 acquired by the vehicle body data acquisition unit 91 (step S12). The control device 90 proceeds to step S13.

[0076] The control device 90 uses the switching unit 92 to determine whether the forklift 1 is stopped (step S13). When the switching unit 92 determines that the vehicle body data acquired by the vehicle body data acquisition unit 91 indicates that the vehicle speed is equal to or less than the second vehicle speed threshold, for example, indicating that the forklift 1 is stopped (Yes in step S13), the control device 90 switches the object detection range in the object detection process to the first range A1. When the switching unit 92 determines that the forklift 1 is stopped (Yes in step S13), the control device 90 proceeds to step S14. When the switching unit 92 determines that the vehicle body data acquired by the vehicle body data acquisition unit 91 indicates that the vehicle speed is greater than the second vehicle speed threshold, for example, indicating that the forklift 1 is not stopped (No in step S13), the control device 90 proceeds to step S16.

[0077] When it is determined that the forklift 1 is stopped (Yes in step S13), the control device 90 sets the first range A1 of a fixed shape stored in the storage unit 99 as the detection range of the object by the setting unit 93 (step S14). More specifically, the setting unit 93 sets the first range A1 of a fixed shape as the detection range of the object based on the length L1, the length L2, and the width W stored in the storage unit 99. The setting unit 93 also sets the first detection range A1 to include a first portion A11 whose alarm level is level 2 and a second portion A12 whose alarm level is level 1. The first detection range A1 may be set without being divided into the first portion A11 and the second portion A12. The control device 90 proceeds to step S15.

[0078] The control device 90 executes a process of detecting an object in the set first range A1 by the determination unit 95 (step S15). The process of detecting an object in the first range A1 will be described later. The control device 90 proceeds to step S18.

[0079] When it is determined that the forklift 1 is not stopped (No in step S13), the control device 90 sets the second range A2 according to the vehicle speed and tire turning angle of the forklift 1 as the object detection range by the setting unit 93 (step S16). More specifically, the setting unit 93 sets the second range A2 changed to a rectangular or arc shape so as to follow the path predicted according to the tire turning angle of the forklift 1. The setting unit 93 also changes the length L of the second range A2 according to the vehicle speed of the forklift 1. Furthermore, the setting unit 93 sets the second detection range A2 including a first portion A21 whose alarm level is level 2 and a second portion A22 whose alarm level is level 1. The second detection range A2 may be set without being divided into the first portion A21 and the second portion A22. The control device 90 proceeds to step S17.

[0080] The control device 90 executes a process of detecting an object in the set second range A2 by the determination unit 95 (step S17). The process of detecting an object in the second range A2 will be described later. The control device 90 proceeds to step S18.

[0081] The control device 90 determines, by the determination unit 95, whether the warning level is greater than 0 and whether the forklift 1 can move backward (step S18). The determination unit 95 determines whether the warning level is greater than 0 and whether the vehicle body data acquired by the vehicle body data acquisition unit 91 indicates that the forklift 1 can move backward. More specifically, if the determination unit 95 determines that the warning level is greater than 0 and that the vehicle body data indicates that the forward / reverse lever of the forklift 1 is in the "reverse" position, the determination unit 95 determines that the warning level is greater than 0 and that the forklift 1 can move backward (Yes in step S18). Note that the forklift 1 may be determined to be able to move backward when the forward / reverse lever of the forklift 1 is in the "reverse" position and the parking brake is released. If the determination unit 95 determines that the warning level is greater than 0 and that the forklift 1 can move backward (Yes in step S18), the process proceeds to step S19. If the vehicle body data indicates that the warning level is 0 or that the forward / reverse lever of the forklift 1 is not in the "reverse" position (No in step S18), the process proceeds to step S20.

[0082] When it is determined that the warning level is greater than 0 and the forklift 1 is capable of moving backward (Yes in step S18), the control device 90 outputs a warning (step S19).

[0083] For example, when the alarm level is level 2, the control device 90 causes the alarm control section 96 to output an alarm of level 2. The alarm control section 96 outputs a control signal to output a continuous buzzer sound "beep" through the speaker of the alarm device 80. The alarm control section 96 outputs a control signal to cause the alarm lamp of the alarm device 80 to flash at 4 [Hz].

[0084] For example, when the alarm level is level 1, the control device 90 causes the alarm control unit 96 to output an alarm of level 1. The alarm control unit 96 outputs a control signal to output an intermittent buzzer sound "beep beep beep" through the speaker of the alarm device 80. The alarm control unit 96 outputs a control signal to cause the alarm lamp of the alarm device 80 to flash at 2 [Hz].

[0085] If the warning level is 0, or if it is not determined that the forklift 1 is capable of moving backward (No in step S18), the control device 90 stops the warning (step S20).

[0086] Next, a method of detecting an object in the first range A1 by the control device 90 of the object detection system 300 will be described with reference to Fig. 10. The control device 90 determines, by the determination unit 95, whether or not the relative position of the object data acquired by the object data acquisition unit 94 indicates that an object has been detected in the first portion A11 of the first range A1 (step S21). If the control device 90 indicates that an object has been detected in the first portion A11 of the first range A1 (Yes in step S21), the control device 90 proceeds to step S22. If the control device 90 does not indicate that an object has been detected in the first portion A11 of the first range A1 (No in step S21), the control device 90 proceeds to step S23.

[0087] If it indicates that an object has been detected in the first portion A11 of the first range A1 (Yes in step S21), the control device 90 sets the warning level to level 2 by the determination unit 95 (step S22). The control device 90 ends the process.

[0088] If it does not indicate that an object has been detected in the first portion A11 of the first range A1 (No in step S21), the determination unit 95 determines whether the relative position of the object data acquired by the object data acquisition unit 94 indicates that an object has been detected in the second portion A12 of the first range A1 (step S23). If it indicates that an object has been detected in the second portion A12 of the first range A1 (Yes in step S23), the control device 90 proceeds to step S24. If it does not indicate that an object has been detected in the second portion A12 of the first range A1 (No in step S23), the control device 90 ends the process.

[0089] If it indicates that an object has been detected in the second portion A22 of the first range A1 (Yes in step S23), the control device 90 sets the warning level to level 1 by the determination unit 95 (step S24). The control device 90 ends the process.

[0090] Next, an object detection method in the second range A2 by the control device 90 of the object detection system 300 will be described with reference to FIG. 11. The processes of steps S32 and S34 are similar to those of steps S22 and S24 in the flowchart shown in FIG. 10. The control device 90 determines, by the determination unit 95, whether or not the relative position of the object data acquired by the object data acquisition unit 94 indicates that an object has been detected in the first portion A21 of the second range A2 (step S31). If the control device 90 indicates that an object has been detected in the first portion A21 of the second range A2 (Yes in step S31), the control device 90 proceeds to step S32. If the control device 90 does not indicate that an object has been detected in the first portion A21 of the second range A2 (No in step S31), the control device 90 proceeds to step S33.

[0091] If it does not indicate that an object has been detected in the first portion A21 of the second range A2 (No in step S31), the determination unit 95 determines whether the relative position of the object data acquired by the object data acquisition unit 94 indicates that an object has been detected in the second portion A22 of the second range A2 (step S33). If it indicates that an object has been detected in the second portion A22 of the second range A2 (Yes in step S33), the control device 90 proceeds to step S34. If it does not indicate that an object has been detected in the second portion A22 of the second range A2 (No in step S33), the control device 90 ends the process.

[0092] The operator confirms that an object has been detected around the forklift 1 and the alarm level by the sound or light emitted from the alarm device 80. Then, the operator performs an operation to avoid a collision with the object. For example, the operator performs a brake operation, releases the accelerator, or operates the steering wheel.

[0093] <Cancel object detection process> Here, a case where the object detection process is cancelled when the vehicle speed of the forklift 1 is equal to or higher than the third vehicle speed threshold value, or when the tire turning angle of the forklift 1 is equal to or higher than the turning angle threshold value, will be described. In this case, after the determination in step S13 of the flow chart shown in FIG. 9 is No, before the process in step S16 is executed, in other words, before the object detection process is executed, a step is provided in which the determination unit 95 determines whether the vehicle speed of the forklift 1 is equal to or higher than the third vehicle speed threshold value, or whether the tire turning angle of the forklift 1 is equal to or higher than the turning angle threshold value (step S13-2). Then, when the determination unit 95 determines that the vehicle speed of the forklift 1 is equal to or higher than the third vehicle speed threshold value, or that the tire turning angle of the forklift 1 is equal to or higher than the turning angle threshold value (Yes in step S13-2), the object detection process in steps S16 and S17 is not executed, and the process is terminated. When steps S16 and S17 are not executed, the operator may be notified that the object detection process has been cancelled by a buzzer sound or a warning lamp via the speaker of the warning device 80. Furthermore, if steps S16 and S17 are not executed, the fact that the object detection process has been canceled may be displayed on the display panel 52 by a buzzer sound or a warning lamp via the speaker of the warning device 80. If the determination unit 95 determines that the vehicle speed of the forklift 1 is not equal to or greater than the third vehicle speed threshold and that the tire turning angle of the forklift 1 is not equal to or greater than the turning angle threshold (No in step S13-2), the process proceeds to step S16, and the object detection process is executed.

[0094] After the determination in step S18 of the flowchart shown in FIG. 9 is Yes, a step may be provided for determining whether the vehicle speed of the forklift 1 is equal to or greater than a third vehicle speed threshold or whether the tire turning angle of the forklift 1 is equal to or greater than the turning angle threshold. If the determination unit 95 determines that the vehicle speed of the forklift 1 is equal to or greater than the third vehicle speed threshold or that the tire turning angle of the forklift 1 is equal to or greater than the turning angle threshold, the processing may be terminated without executing step S19 for outputting an alarm.

[0095] <Computer System> FIG. 12 is a block diagram showing an example of a computer system 1000 according to this embodiment. The above-mentioned control device 90 includes the computer system 1000. The computer system 1000 has a processor 1001 such as a CPU (Central Processing Unit), a main memory 1002 including a non-volatile memory such as a ROM (Read Only Memory) and a volatile memory such as a RAM (Random Access Memory), a storage 1003, and an interface 1004 including an input / output circuit. The functions of the above-mentioned control device 90 are stored in the storage 1003 as a program. The processor 1001 reads the program from the storage 1003, expands it in the main memory 1002, and executes the above-mentioned process according to the program. The program may be distributed to the computer system 1000 via a network.

[0096] <Effects> As described above, in this embodiment, the switching unit 92 switches the range for detecting an object between the first range A1 and the second range A2 in accordance with the vehicle speed of the forklift 1. In this embodiment, the determination unit 95 determines whether or not an object has been detected in the first range A1 or the second range A2 switched by the switching unit 92. According to this embodiment, by switching between the first range A1 and the second range A2 in accordance with the vehicle speed of the forklift 1, it is possible to appropriately determine whether or not an object is present around the forklift 1.

[0097] In this embodiment, the first range A1 and the second range A2 are included in the detection area of ​​the object detection device 70. In this embodiment, when it is determined that an object exists in the first range A1 or the second range A2, an alarm is output from the alarm device 80. According to this embodiment, when an object exists in the vicinity of the forklift 1, an alarm can be appropriately output. In this way, according to this embodiment, it is possible to prevent the alarm from being issued inadvertently and frequently.

[0098] In this embodiment, the width W of the first range A1 and the second range A2 includes the vehicle width Wr of the forklift 1. In this embodiment, the first range A1 and the second range A2 are set to have the minimum width required for the forklift 1 to travel. According to this embodiment, it is possible to appropriately determine whether or not an object exists around the forklift 1.

[0099] In this embodiment, for example, when the forklift 1 is stopped, the range for detecting an object is switched to a first range A1. In this embodiment, when the forklift 1 is moving backward, the range for detecting an object is switched to a second range A2. According to this embodiment, even when the vehicle speed is low, such as when the forklift 1 is stopped, it is possible to appropriately determine whether or not an object exists around the forklift 1.

[0100] In this embodiment, when the range for detecting an object is switched to the second range A2, if the vehicle speed of the forklift 1 is equal to or lower than the first vehicle speed threshold, such as immediately after the forklift 1 starts to move backward, the first portion A21 of the second range A2 is set as the fixed range. According to this embodiment, even if the vehicle speed is low, such as immediately after the forklift 1 starts to move backward, the length L of the second range A2 can be prevented from becoming zero. Furthermore, by making the fixed range shorter than the first range, when an object is detected in the first range, the object can be detected in a wide range, allowing the forklift to be operated while checking the safety around the forklift, and after switching to the second range, unnecessary alarms can be suppressed.

[0101] In this embodiment, when the forklift 1 is moving backward, the shape of the second area A2 is changed according to the vehicle speed and tire turning angle of the forklift 1. According to this embodiment, the second area A2 having the minimum necessary size and optimal shape can be set along the predicted path of the forklift 1.

[0102] In this embodiment, the first range A1 and the second range A2 are divided into a plurality of parts associated with different warning levels. In this embodiment, when an object is present in any of the first part A11, the second part A12, the first part A21, and the second part A22, an appropriate warning can be output based on the warning level. According to this embodiment, the operator can check the warning level.

[0103] In this embodiment, when the vehicle speed is equal to or higher than the third vehicle speed threshold, it is possible to prevent the output of an alarm. When the vehicle speed is equal to or higher than the third vehicle speed threshold, the distance traveled by the forklift 1 from when an object is detected until when an alarm is output becomes long. This may cause a large change in the relative position between the forklift 1 and the object during the time from when the object is detected until when an alarm is output. According to this embodiment, it is possible to suppress the output of an alarm at an inappropriate time.

[0104] In this embodiment, it is possible to prevent an alarm from being output when the tire turning angle of the forklift 1 is equal to or greater than the turning angle threshold. When the tire turning angle is equal to or greater than the turning angle threshold, the second range A2 may fall outside the detection range of the object detection device 70. According to this embodiment, the second range A2 can be appropriately set.

[0105] In this embodiment, an alarm may be output from the left alarm device 80L only when an object is detected by the left radar 70L or when an object is detected to the left of the front-rear axis of the forklift 1. In this embodiment, an alarm may be output from the right alarm device 80R only when an object is detected by the right radar 70R or when an object is detected to the right of the front-rear axis of the forklift 1. According to this embodiment, the operator can intuitively confirm the direction in which the object is present.

[0106] <Modification> In the above, when the determination unit 95 determines that the warning level is greater than 0 and that the forklift 1 can move backward, the control device 90 may output a control signal to the vehicle control device 69 for controlling the traveling state of the forklift 1. For example, the vehicle control device 69 may output a control signal to the power generating device so as to execute an output reduction process. This reduces the vehicle speed of the forklift 1 and stops the forklift 1. For example, the vehicle control device 69 may output a control signal to the power generating device so as to execute a brake process. This reduces the vehicle speed of the forklift 1 or stops the traveling of the forklift 1. For example, the vehicle control device 69 may output a control signal to the steering device so as to execute a traveling direction change process. This changes the traveling direction of the forklift 1 so that no object is present in the path of the forklift 1.

[0107] In the above description, the object detection device 70 includes the left radar 70L and the right radar 70R, but is not limited to this. The number of object detection devices 70 may be one, or three or more.

[0108] Although the above description has been given of three alarm levels, the alarm level is not limited to this and may be four or more alarm levels, or may be two alarm levels.

[0109] In the above description, the turning angle acquisition unit 911 has been described as acquiring the tire turning angle from the vehicle control device 69, but is not limited to this. The turning angle acquisition unit 911 may detect the amount of operation of the steering device of the forklift 1 based on the vehicle body data of the forklift 1 acquired from the vehicle control device 69, and calculate the tire turning angle of the rear wheels 12 of the forklift 1.

[0110] In the above description, the vehicle speed acquisition unit 912 has been described as acquiring the vehicle speed from the vehicle control device 69, but is not limited to this. The vehicle speed acquisition unit 912 may calculate the vehicle speed of the forklift 1 based on a rotation speed value as a detection value of a rotation speed sensor included in the vehicle body data of the forklift 1 acquired from the vehicle control device 69. The vehicle speed acquisition unit 912 may also detect the vehicle speed of the forklift 1 based on a detection value of a rotation speed sensor included in the acquired vehicle body data of the forklift 1.

[0111] In the above description, the width W is described as including the vehicle width Wr of the forklift 1, but is not limited thereto. The width W may be a width shorter than the vehicle width Wr of the forklift 1.

[0112] In the above description, the work machine is described as being a forklift 1, but is not limited to this. The work machine may be a wheel loader, a hydraulic excavator, or the like that is driven by power from a battery or power obtained from a generator driven by an engine or the like. [Explanation of symbols]

[0113] 1...forklift (working machine), 10...vehicle body, 13...fork, 16...rear pillar, 60...vehicle body data acquisition device, 61...steer angle sensor (steering angle detection unit), 62...vehicle speed sensor (vehicle speed detection unit), 69...vehicle control device, 70...object detection device (object detection unit), 70L...left radar (object detection unit), 70R...right radar (object detection unit), 80...alarm device (alarm unit), 80L...left radar alarm device, 80R...right alarm device, 90...control device, 91...vehicle body data acquisition unit, 92...switching unit, 93...setting unit, 94...object data acquisition unit, 95...determination unit, 96...alarm control unit, 99...memory unit, 300...object detection system, A1...first range (first detection range), A11...first part, A12...second part, A2...second range (second detection range), A21...first part, A22...second part.

Claims

1. 1. A system for controlling a work machine, comprising: an object detection device for detecting objects around the work machine; A control device; Equipped with The control device includes: Obtaining a detection result from the object detection device; Detecting a vehicle speed of the work machine; setting an alarm range for detecting the object in the vicinity of the work machine; changing a length of the warning range in a traveling direction of the work machine according to the detected vehicle speed; determining whether the object is detected within the warning range; system.

2. The warning range is divided along a traveling direction into a first portion close to the vehicle body and a second portion farther from the vehicle body than the first portion and having a lower warning level than the first portion, The control device includes: a length of the second portion of the warning range in a traveling direction of the work machine is changed in accordance with the detected vehicle speed; The system of claim 1 .

3. The control device includes: When the detected vehicle speed is equal to or less than a first vehicle speed threshold, the first portion is set as a fixed range having a fixed length, and when the detected vehicle speed exceeds the first vehicle speed threshold, the fixed length of the first portion is lengthened according to the vehicle speed. The system of claim 2.

4. The control device includes: Detecting a steering angle of the work machine; setting the warning range based on the detected vehicle speed and the steering angle; The system of claim 1 .

5. A plurality of warning devices are provided around the driver's seat of the work machine, When the control device determines that the object has been detected, the control device outputs an alarm from the alarm device. The system of claim 1 .

6. The warning device is installed in a rear pillar. The system of claim 5.

7. The control device outputs a control signal for controlling a traveling state of the work machine based on a determination of whether the object has been detected. The system of claim 1 .

8. The control device outputs a control signal to reduce a vehicle speed of the work machine. The system of claim 7.

9. The control device outputs a control signal to stop the work machine. The system of claim 7.

10. an object detection device for detecting objects around the work machine; A control device; Equipped with The control device includes: Obtaining a detection result from the object detection device; Detecting a vehicle speed of the work machine; setting an alarm range for detecting the object in the vicinity of the work machine; changing a length of the warning range in a traveling direction of the work machine according to the detected vehicle speed; determining whether the object is detected within the warning range; Working machinery.

11. A method for controlling a work machine including an object detection device for detecting objects around the work machine and a control device, the method comprising: obtaining a detection result from the object detection device; Detecting a vehicle speed of the work machine; setting an alarm range for detecting the object in the vicinity of the work machine; changing a length of the warning range in a traveling direction of the work machine in accordance with the detected vehicle speed; determining whether the object is detected within the warning range; The method includes:

Images