Material handling vehicles

Abstract

To provide a cargo handling vehicle that can avoid contact with overhead obstacles while suppressing a decrease in work efficiency. [Solution] A cargo handling vehicle comprising a vehicle body 2, a cargo handling device 3 including a mast, backrest and forks, a control unit, and a sensor unit 5 that detects objects using laser light and outputs distance information to the object and angle information of the laser light to the control unit, wherein the control unit sets forward regions R1 and R2 through which the cargo handling device passes in the detection area, calculates the highest point P1 of the cargo handling device 3 in the forward regions R1 and R2 based on the distance information and angle information, sets obstacle detection regions R3 and R4 behind the forward regions R1 and R2 in the detection area, changes the height of the upper end of the obstacle detection regions R3 and R4 in correlation with the highest point P1, and limits the vehicle speed of the vehicle body 2 when detection is detected by the sensor unit 5 in the obstacle detection regions R3 and R4.

Description

Technical Field

[0001] The present invention relates to a cargo handling vehicle such as a forklift.

Background Art

[0002] As a conventional cargo handling vehicle, for example, the one described in Patent Document 1 is known. The cargo handling vehicle described in Patent Document 1 detects obstacles in the traveling direction. Specifically, the cargo handling vehicle described in Patent Document 1 calculates the height H2 of the mast based on the height of the obstacle sensor, calculates a first line connecting the position at a first distance Lf from the obstacle sensor in the traveling direction and the obstacle sensor, calculates a second line connecting the position at a height H2 away from the above position in the height direction and the obstacle sensor, and calculates an angle θf formed by the first line and the second line. When an obstacle is detected by the obstacle sensor within the range of the angle θf, the cargo handling vehicle described in Patent Document 1 prohibits or stops traveling.

[0003] In addition, the cargo handling vehicle described in Patent Document 1 also detects upper obstacles. Specifically, the cargo handling vehicle described in Patent Document 1 calculates a first height H4 lower than the height to an obstacle above the cargo handling vehicle based on the height of the obstacle sensor, and calculates a second height H6 to the upper end of the mast based on the height of the obstacle sensor. When the second height H6 is greater than or equal to the first height H4, the cargo handling vehicle described in Patent Document 1 prohibits or stops the mast from rising.

[0004] The cargo handling vehicle described in Patent Document 1 can avoid contact with upper obstacles. However, in the detection of obstacles in the traveling direction, the cargo handling vehicle described in Patent Document 1 detects an obstacle at a certain distance ahead and prohibits or stops traveling. Therefore, even when approaching a wall or shelf within the work area, it prohibits or stops traveling. As a result, in a narrow cargo handling work site, traveling prohibition or traveling stop frequently occurs in the cargo handling vehicle described in Patent Document 1, and the work efficiency is significantly reduced.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2021-111138 [Overview of the project] [Problems that the invention aims to solve]

[0006] The present invention has been made in view of the above circumstances, and its objective is to provide a cargo handling vehicle that can avoid contact with overhead obstacles and suppress a decrease in work efficiency. [Means for solving the problem]

[0007] To solve the above problems, the cargo handling vehicle according to the present invention is A vehicle body that performs driving operations within a predetermined work area, A cargo handling device including a mast, backrest, and forks that perform a lifting and lowering operation at the front of the vehicle body, A control unit that controls the aforementioned travel operation and the aforementioned lifting operation, A sensor unit that uses laser light to detect an object in a detection area above the vehicle body and outputs distance information to the object and angle information of the laser light to the control unit, A cargo handling vehicle equipped with, The control unit, Within the detection area, a forward region through which the cargo handling device passes is defined, and based on the distance information and the angle information, the highest point of the cargo handling device in the forward region is calculated. In the aforementioned detection area, an obstacle detection area is set in the rear area behind the front area, and the height of the upper end of the obstacle detection area is changed in correlation with the highest point. The vehicle is characterized by limiting the vehicle speed when the sensor unit detects an obstacle in the obstacle detection area.

[0008] In the aforementioned cargo handling vehicle, The aforementioned sensor unit is It is installed at the upper end of the vehicle body and detects the object by scanning the laser beam vertically. The control unit, The forward region is defined as a first forward region through which the load on the forks and the backrest pass, and a second forward region through which the mast passes. The system can be configured to calculate the first highest point of the cargo handling device in the first forward region and the second highest point of the cargo handling device in the second forward region, and to set the higher of these two points as the highest point.

[0009] In the aforementioned cargo handling vehicle, If the first highest point and the second highest point are located on the laser beam at the same angle, The control unit, Based on the distance information and angle information relating to the second highest point, the first highest point can be calculated, and the system can be configured to set the first highest point as the highest point.

[0010] In the aforementioned cargo handling vehicle, The control unit, The system can be configured such that if the highest point decreases when the aforementioned lifting operation is not being performed, the height of the upper end of the obstacle detection area is changed, while if the highest point increases when the aforementioned lifting operation is not being performed, the height of the upper end of the obstacle detection area is not changed.

[0011] In the aforementioned cargo handling vehicle, The control unit, The obstacle detection area can be configured to be set only when the vehicle is moving in reverse.

[0012] In the aforementioned cargo handling vehicle, The control unit, The obstacle detection area can include multiple regions divided in the front-to-back direction, and the content of the vehicle speed limit can be changed in each region. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a cargo handling vehicle that can avoid contact with upper obstacles and suppress a decrease in work efficiency.

Brief Description of the Drawings

[0014] [Figure 1] The forklift according to the present invention, where (A) is a side view and (B) is a plan view. [Figure 2] It is a block diagram of the sensor unit and the control unit according to the present invention. [Figure 3] It is a diagram showing a front area for calculating the highest point of the cargo handling device. [Figure 4] It is a diagram showing an obstacle detection area for detecting upper obstacles. [Figure 5] It is a diagram when the first highest point P1 and the second highest point P2 exist on the same light ray.

Modes for Carrying Out the Invention

[0015] Hereinafter, embodiments of the cargo handling vehicle according to the present invention will be described with reference to the accompanying drawings.

[0016] FIG. 1 shows a forklift 1 according to an embodiment of the present invention. The forklift 1 is a counterbalance type forklift and corresponds to the "cargo handling vehicle" of the present invention. The forklift 1 performs a traveling operation and a cargo handling operation in a predetermined work area.

[0017] The work area is an area inside an arbitrary building such as a factory or a warehouse. Above the work area, there are various obstacles C such as a low ceiling, a gate, or a protrusion (hereinafter, "upper obstacle C"). Also, a plurality of shelves (not shown) are provided in the work area, and loads W and the like are stored on the shelves.

[0018] The forklift 1 includes a vehicle body 2, a cargo handling device 3, a control unit 4, and a sensor unit 5.

[0019] The vehicle body 2 is equipped with front and rear wheels at the bottom and a driver's seat and head guard at the top. The front wheels are drive wheels driven by a traction motor, and the rear wheels are steering wheels steered (turned) by a steering motor. The driver's seat is the operator's seat, and the head guard is a protective frame to protect the operator in the driver's seat from falling objects.

[0020] Vehicle body 2 is equipped with an accelerator and a brake at the driver's feet. The accelerator is an accelerator pedal configured to be operated by the operator in the driver's seat by pressing it with their foot. When the accelerator is in the ON state (pedal pressed), it accelerates vehicle body 2 according to the amount of pedal depression (accelerator opening), while when it switches from the ON state to the OFF state (pedal not pressed), it generates a weak regenerative brake to decelerate vehicle body 2. The brake is a brake pedal configured to be operated by the operator in the driver's seat by pressing it with their foot. When the brake is in the ON state (pedal pressed), it generates a stronger regenerative brake than the accelerator's regenerative brake to decelerate vehicle body 2, while when it is in the OFF state, it does not generate regenerative brake. By operating the accelerator and / or brake, the operator can make vehicle body 2 perform driving actions such as acceleration and deceleration.

[0021] The vehicle body 2 is equipped with a steering wheel, forward / reverse levers, and cargo handling levers (tilt lever and lift lever) in front of the driver's seat. The steering wheel is connected to the rear wheels via a steering control mechanism 4C, which will be described later. By rotating the steering wheel, the operator can change the direction of the rear wheels (turning angle) according to the direction of rotation. The forward / reverse lever is located below the steering wheel and switches the vehicle body 2's movement between forward and reverse. When the operator tilts the forward / reverse lever forward (forward position) and turns on the accelerator, the vehicle body 2 can move forward. When the operator tilts the forward / reverse lever backward (reverse position) and turns on the accelerator, the vehicle body 2 can move backward. The cargo handling lever is connected to the cargo handling device 3 via a cargo handling control mechanism 4B, which will be described later. By operating the cargo handling lever, the operator can make the cargo handling device 3 perform cargo handling operations.

[0022] The cargo handling device 3 comprises a mast 3A, a backrest 3B and forks 3C, a tilt cylinder, and a lift cylinder, and performs cargo handling operations. The cargo handling operations include raising and lowering the mast 3A and forks 3C.

[0023] Mast 3A is located on the front side of the vehicle body 2 and raises and lowers the forks 3C. Mast 3A comprises an outer mast and an inner mast. The outer mast comprises a pair of left and right guide rails extending vertically and a cross beam connecting the upper ends of the guide rails. The inner mast comprises a pair of left and right rails extending vertically and a cross beam (connecting member) connecting the upper ends of the rails. The inner mast is located inside the guide rails of the outer mast and rises and lowers along the guide rails of the outer mast at half the speed of the backrest 3B and forks 3C. The outer mast does not rise or lower.

[0024] The backrest 3B is a frame designed to prevent the load W loaded on the forks 3C from shifting backward, and is equipped with a lift bracket at its lower part. The lift bracket supports the forks 3C and moves up and down along the mast 3A. That is, when the mast 3A (inner mast) moves up and down, the backrest 3B (including the lift bracket) and the forks 3C move up and down. The forks 3C are a pair of L-shaped arms, one on each side, and are located in front of the backrest 3B.

[0025] The tilt cylinder is a hydraulic cylinder used to tilt the mast 3A in the forward and backward directions. For example, tilting the tilt lever forward extends the tilt cylinder, causing the mast 3A to tilt forward, and tilting the tilt lever backward retracts the tilt cylinder, causing the mast 3A to tilt backward. Returning the tilt lever to the neutral position (a position where it neither tilts forward nor backward) stops the tilting of the mast 3A.

[0026] The lift cylinder is a hydraulic cylinder used to raise and lower mast 3A. For example, tilting the lift lever forward causes the lift cylinder to retract and the inner mast to lower, while tilting the lift lever backward causes the lift cylinder to extend and the inner mast to rise. Returning the lift lever to the neutral position (neither tilted forward nor backward) stops the raising and lowering of the inner mast.

[0027] The control unit 4 controls the driving operation of the vehicle body 2 and the cargo handling operation of the cargo handling device 3. As shown in Figure 2, the control unit 4 comprises a vehicle control unit 4A, a cargo handling control mechanism 4B, a steering control mechanism 4C, and a driving control mechanism 4D.

[0028] The vehicle control unit 4A controls the driving and cargo handling operations by controlling the cargo handling control mechanism 4B, the steering control mechanism 4C, and the driving control mechanism 4D. The vehicle control unit 4A receives sensor signals from the sensor unit 5, including distance information and angle information described later, and acquires detection signals necessary for controlling the driving and / or cargo handling operations from various sensors other than the sensor unit 5. The vehicle control unit 4A is composed of, for example, an MPU (including memory, etc.). The vehicle control unit 4A also performs highest point detection and rearward detection, the specific processes for these will be described later.

[0029] The cargo handling control mechanism 4B includes, for example, a cargo handling inverter, a cargo handling motor, a hydraulic circuit, etc. The vehicle control unit 4A acquires detection signals related to the amount of lever operation from the cargo handling levers (tilt lever and lift lever) and controls the cargo handling device 3 via the cargo handling control mechanism 4B.

[0030] The steering control mechanism 4C includes, for example, a steering motor, a power steering device, a hydraulic circuit, etc. The vehicle control unit 4A acquires detection signals regarding the direction and amount of rotation of the steering wheel and controls the rear wheels, which are the steering wheels, via the steering control mechanism 4C.

[0031] The driving control mechanism 4D includes, for example, a driving inverter, a driving motor, a hydraulic circuit, etc. The vehicle control unit 4A acquires detection signals related to the accelerator opening, brake state, and vehicle speed, etc., and controls the front wheels, which are the drive wheels, via the driving control mechanism 4D. As part of this control, the vehicle control unit 4A performs speed control to bring the driving speed of the vehicle body 2 closer to a predetermined target speed. Specifically, the vehicle control unit 4A acquires the driving speed of the vehicle body 2 based on the detection signal of the vehicle speed sensor, and calculates the target speed based on the detection signal of the accelerator sensor and / or the detection signal of the brake sensor. The vehicle control unit 4A performs PI control or PID control to bring the driving speed closer to the target speed. The target speed is calculated, for example, by the formula: Target speed = Set speed × Accelerator opening [%]. The set speed is a speed preset in the vehicle control unit 4A.

[0032] The sensor unit 5 is an area sensor that detects objects in a predetermined detection area. In this embodiment, a single 2D-LiDAR is used as the sensor unit 5. As shown in Figure 1, the sensor unit 5 (2D-LiDAR) is mounted on the upper part of the vehicle body 2 at an angle that allows it to irradiate laser light vertically upward relative to the road surface. Specifically, the sensor unit 5 is mounted at the upper end of the head guard and at the center in the left-right direction. The detectable area R of the sensor unit 5 is limited to the left-right center of the vehicle body 2 and is 180° or more in the front-rear direction (180° in Figure 1). If a 3D-LiDAR is used as the sensor unit 5, the detectable area R can be widened in the left-right direction according to the irradiation range of the laser light.

[0033] LiDAR can be classified into two types: data output type and area setting type. Data output type LiDAR outputs distance information acquired from the reflected light of the laser beam for each laser beam irradiation angle. On the other hand, area setting type LiDAR outputs a detection signal when an object is detected within a set area.

[0034] The sensor unit 5 in this embodiment is a data output type 2D-LiDAR. The sensor unit 5 scans the laser beam in a predetermined step angle within the detectable area R and generates a sensor signal that includes distance information relating to the distance from the sensor unit 5 to the object and angle information relating to the irradiation angle (scanning angle) of the laser beam, based on the reflected light from the object irradiated with the laser beam.

[0035] As shown in Figure 2, the sensor unit 5 comprises a sensor main circuit unit 5A and a sensor control unit 5B.

[0036] The sensor main circuit section 5A includes a light-emitting section that emits laser light, a light-receiving section that receives reflected laser light, a deflection mirror, and a scanning section that scans the laser light at predetermined step angles and adjusts the angle of the deflection mirror to guide the reflected light to the light-receiving section. The light-receiving section outputs a signal correlated with the amount of reflected light received to the sensor control section 5B.

[0037] The sensor control unit 5B includes a drive processing unit that drives the sensor main circuit unit 5A, an angle detection unit that detects the irradiation angle (scanning angle) of the laser beam, a distance calculation unit that calculates the distance to the object, and a signal generation unit that generates a sensor signal including distance information and angle information. The signal generation unit outputs the generated sensor signal to the vehicle control unit 4A. As a known technique (e.g., TOF method) can be used for calculating the distance to the object, a description is omitted.

[0038] The vehicle control unit 4A has pre-stored area data relating to the position information of the detectable area R (for example, the position information of the detectable area R relative to the sensor unit 5), and can identify at what position within the detectable area R an object was detected from the distance information and angle information included in the sensor signal. In other words, the vehicle control unit 4A can perform the highest point detection and rearward detection described later based on the distance information and angle information included in the sensor signal.

[0039] Figure 3 shows the forward regions (first forward region R1 and second forward region R2) for calculating the highest point of the cargo handling device 3. Here, the highest point of the cargo handling device 3 refers to the highest position among the upper end position of the load W held by the forks 3C, the upper end position of the backrest 3B, and the upper end position of the mast 3A (in this embodiment, the connecting member of the inner mast).

[0040] The vehicle control unit 4A performs a maximum point detection during the lifting and lowering operation of the cargo handling device 3. When the maximum point is detected, the vehicle control unit 4A sets a first forward region R1 and a second forward region R2 in the detectable area R. Specifically, the vehicle control unit 4A sets the coordinates corresponding to the first forward region R1 and the second forward region R2 in the coordinate system of the area data of the detectable area R.

[0041] The first forward region R1 is set as the area through which the load W on the forks 3C and the backrest 3B pass, but through which the inner mast does not pass. The second forward region R2 is set as the area through which the inner mast passes, but through which the load W on the forks 3C and the backrest 3B do not pass. The lower ends of the first forward region R1 and the second forward region R2 are set to the height of the upper end of the head guard. The upper ends of the first forward region R1 and the second forward region R2 are set to a height equal to or greater than the maximum height that the highest point of the cargo handling device 3 can take (for example, the height when the forks 3C are holding the highest load W and the forks 3C have risen to their highest position). The shapes of the first forward region R1 and the second forward region R2 can be changed as appropriate.

[0042] The vehicle control unit 4A calculates the highest point of the cargo handling device 3 during its lifting and lowering operation. Specifically, based on distance and angle information acquired from the sensor unit 5 at predetermined intervals, the vehicle control unit 4A calculates the highest point of the cargo handling device 3 in the first forward region R1 (first highest point) and the highest point of the cargo handling device 3 in the second forward region R2 (second highest point). Candidates for the first highest point are the upper end position of the load W held by the forks 3C or the upper end position of the backrest 3B, and candidates for the second highest point are the upper end position of the connecting member of the inner mast. The vehicle control unit 4A compares the first highest point and the second highest point and sets the higher one as the highest point of the cargo handling device 3.

[0043] Figure 4 shows the obstacle detection regions (first rear region R3 and second rear region R4) for detecting the overhead obstacle C.

[0044] The vehicle control unit 4A performs rearward detection when the vehicle body 2 is moving in reverse. When rearward detection is performed, the vehicle control unit 4A sets the first rearward area R3 and the second rearward area R4 behind the forward area (first forward area R1 and second forward area R2) in the detectable area R. Specifically, the vehicle control unit 4A sets the coordinates corresponding to the first rearward area R3 and the second rearward area R4 in the coordinate system of the area data of the detectable area R.

[0045] The first rear region R3 is a rectangular area located directly above the vehicle body 2. The front end of the first rear region R3 is set to a position where the tilted cargo handling device 3 is not detected, and the rear end of the first rear region R3 is set to the same position as the rear end of the vehicle body 2 (or forward of the rear end of the vehicle body 2). The lower end of the first rear region R3 is set to the height of the sensor unit 5 (the height of the upper end of the head guard). The upper end of the first rear region R3 is set to the same position as the highest point of the cargo handling device 3 (or a position at the highest point + α [cm] (where α is an arbitrary value)).

[0046] In the case of Figure 4, if the first highest point is P1 and the second highest point is P2, the highest point of the cargo handling device 3 is P1. Therefore, the vehicle control unit 4A sets the upper end of the first rear region R3 to the same position as the first highest point P1. The shape of the first rear region R3 can be changed as appropriate.

[0047] The second rear region R4 is the rectangular area located directly above and behind the vehicle body 2, excluding the first rear region R3. The front end of the second rear region R4 is set at a position where the tilted cargo handling device 3 is not detected (in this embodiment, the same position as the front end of the first rear region R3). The rear end of the second rear region R4 is set behind the rear end of the vehicle body 2. The lower end of the second rear region R4 is set at the height of the sensor unit 5 (the height of the upper end of the head guard). The upper end of the second rear region R4 is set above the upper end of the first rear region R3 (or at the same position as the upper end of the first rear region R3). The shape of the second rear region R4 can be changed as appropriate.

[0048] If the highest point of the cargo handling device 3 is lower than the lower end of the forward area (first forward area R1 and second forward area R2) (for example, in the case of Figure 3), the vehicle control unit 4A does not set the obstacle detection area (first rear area R3 and second rear area R4).

[0049] When rearward detection occurs, the vehicle control unit 4A determines whether or not an overhead obstacle C exists in the first rearward region R3 and / or the second rearward region R4, based on distance information and angle information acquired from the sensor unit 5 at predetermined intervals. If an overhead obstacle C exists, the vehicle control unit 4A limits the vehicle speed of the vehicle body 2 (including stopping the vehicle).

[0050] If an overhead obstacle C is present in the first rear area R3, the vehicle control unit 4A limits the upper limit speed of the vehicle body 2 when reversing to a first speed (e.g., 2 km / h). If an overhead obstacle C is present in the second rear area R4, the vehicle control unit 4A limits the upper limit speed of the vehicle body 2 when reversing to a second speed greater than the first speed (e.g., 4 km / h).

[0051] Figure 5 shows the case where the first highest point P1 and the second highest point P2 lie on the same angle laser beam (ray L).

[0052] The sensor unit 5 scans the laser beam in a counterclockwise (or clockwise) direction vertically at a predetermined step angle within the detectable area R. If the first highest point P1 and the second highest point P2 are on the same angle of the laser beam (ray L), the ray L is reflected at the second highest point P2 and does not reach the first highest point P1. As a result, the sensor unit 5 can acquire distance information to the second highest point P2, but cannot acquire distance information to the first highest point P1.

[0053] In this regard, when detecting the highest point, the vehicle control unit 4A determines, based on distance information and angle information, whether the first highest point P1 and the second highest point P2 are on the same angle of the laser beam. When the laser beam is scanned counterclockwise in Figure 5, the sensor unit 5 detects the connecting member of the inner mast in the second front region R2 before detecting the cargo W or backrest 3B in the first front region R1, and immediately after it stops detecting the connecting member of the inner mast in the second front region R2 (continuously from the detection of the lower end of the connecting member), it detects the cargo W or backrest 3B in the first front region R1. This series of detection results is referred to as detection result A. Note that in the second front region R2, only the connecting member of the inner mast is detected, and parts other than the connecting member are not detected.

[0054] If the first highest point P1 and the second highest point P2 lie on the same angle of the laser beam, then in a single scan of the laser beam, the coordinate system of the area data for the detectable area R will show a trajectory (the trajectory of the detected object) corresponding to the detection result A. The vehicle control unit 4A performs the following processing to determine that the first highest point P1 and the second highest point P2 lie on the same angle of the laser beam.

[0055] If, in one scan of the laser beam (scanning cycle), detection occurs in the second forward region R2 (detection of the connecting member of the inner mast) before detection occurs in the first forward region R1, the vehicle control unit 4A first stores the second highest point P2 as the highest point. Subsequently, if, in the same scanning cycle, detection occurs in the first forward region R1 immediately following detection in the second forward region R2 (in the case of detection result A), the vehicle control unit 4A determines that the first highest point P1 and the second highest point P2 are on the laser beam at the same angle, and rewrites the highest point as follows.

[0056] When the vehicle control unit 4A determines that the first highest point P1 and the second highest point P2 are on the same angle laser beam (ray L), it calculates the extension of ray L based on distance and angle information for the second highest point P2. The vehicle control unit 4A also calculates the extension L' of the front of the backrest 3B and calculates the intersection point of the extension of ray L and extension L'. The vehicle control unit 4A sets this intersection point as the first highest point P1' (in Figure 5, P1' and P1 are in approximately the same position, so P1' is not shown) and sets (rewrites) the first highest point P1' as the highest point of the cargo handling device 3. As a result, when rearward detection occurs, the vehicle control unit 4A can set the first rearward region R3 and the second rearward region R4 based on the first highest point P1' (≒ first highest point P1).

[0057] Furthermore, when calculating the intersection point between the extension of ray L and extension L', the extension of the front of the backrest 3B at a position β [cm] in front (β is an arbitrary value) may be used instead of extension L'. Also, although the above explanation described the case where the first highest point P1 lies on the extension of ray L, the same process can be applied even when the first highest point P1 is slightly below the extension of ray L (for example, a few centimeters below), as long as the trajectory corresponding to the detection result A is shown in the coordinate system of the area data of the detectable area R.

[0058] As described above, the vehicle control unit 4A performs a highest point detection to calculate the highest point of the cargo handling device 3, and sets the obstacle detection area (first rear area R3 and second rear area R4) in correlation with the highest point of the cargo handling device 3 when rearward detection is performed. If the highest point of the cargo handling device 3 is high, the height of the upper edge of the obstacle detection area will be high, and if the highest point of the cargo handling device 3 is low, the height of the upper edge of the obstacle detection area will be low. For this reason, when the highest point of the cargo handling device 3 is low, the forklift 1 can pass under the overhead obstacle C that it might come into contact with when the highest point of the cargo handling device 3 is high, without limiting the vehicle speed. Thus, with the forklift 1, contact with the overhead obstacle C can be avoided when reversing, and a decrease in work efficiency can be suppressed.

[0059] When reversing, forklift 1 has two obstacle detection areas (first rear area R3 and second rear area R4). Therefore, with forklift 1, gradual deceleration can be performed when reversing, and contact with the overhead obstacle C can be reliably avoided. Note that forklift 1 may have three or more obstacle detection areas, and the content of the vehicle speed limit may be changed in each area. Also, if gradual deceleration is not necessary, a single obstacle detection area may be set.

[0060] In forklift 1, the vehicle control unit 4A can detect the highest point even when the cargo handling device 3 is not being raised or lowered. When the cargo handling device 3 is not being raised or lowered, the vehicle control unit 4A resets the obstacle detection area. For example, when forklift 1 is facing a shelf during a lifting operation, the vehicle control unit 4A may set the top of the shelf as the highest point of the cargo handling device 3. However, when forklift 1 moves away from the shelf and the highest point decreases, the vehicle control unit 4A lowers the height of the top of the obstacle detection area (first rear area R3 and second rear area R4) according to the decreased highest point.

[0061] On the other hand, if the highest point of the cargo handling device 3 rises when the cargo handling device 3 is not being raised or lowered, the vehicle control unit 4A maintains the height of the upper edge of the obstacle detection area (first rear area R3 and second rear area R4) without resetting the obstacle detection area. As a result, the forklift 1 can pass under a low ceiling that is higher than the obstacle detection area but is included in the front area (first front area R1 and second front area R2) without limiting its vehicle speed.

[0062] Although embodiments of the cargo handling vehicle according to the present invention have been described above, the present invention is not limited to the above embodiments.

[0063] The cargo handling vehicle according to the present invention comprises a vehicle body that travels within a predetermined work area, a cargo handling device including a mast, backrest, and forks that move up and down in front of the vehicle body, a control unit that controls the travel and lifting movements, and a sensor unit that uses laser light to detect objects in a detection area above the vehicle body and outputs distance information to the object and angle information of the laser light to the control unit. The control unit sets a forward area through which the cargo handling device passes within the detection area, calculates the highest point of the cargo handling device in the forward area based on the distance information and angle information, sets an obstacle detection area in the rear area behind the forward area within the detection area, changes the height of the upper end of the obstacle detection area in correlation with the highest point, and if the sensor unit detects an obstacle in the obstacle detection area, the configuration can be changed as appropriate to limit the vehicle speed of the vehicle body.

[0064] For example, the control unit may define a single forward region.

[0065] The speed limit specified above can be set to any speed as long as it is lower than the vehicle's maximum speed when reversing.

[0066] Although the material handling vehicle of the present invention was described using a counterbalanced type forklift as an example in the above embodiment, it may also be a reach type forklift or another type of forklift. Furthermore, the material handling vehicle of the present invention is not limited to a forklift, and may be a vehicle other than a forklift (for example, a transport vehicle) as long as it is equipped with a material handling device capable of lifting and lowering. [Explanation of Symbols]

[0067] 1 Forklift 2. Vehicle body 3. Cargo handling equipment 3A Mast 3B Backrest 3C Fork 4. Control Unit 5. Sensor section

Claims

1. A vehicle body that performs driving operations within a predetermined work area, A cargo handling device including a mast, backrest, and forks that perform a lifting and lowering operation at the front of the vehicle body, A control unit that controls the aforementioned travel operation and the aforementioned lifting operation, A sensor unit that uses laser light to detect an object in a detection area above the vehicle body and outputs distance information to the object and angle information of the laser light to the control unit, A cargo handling vehicle equipped with, The control unit, Within the detection area, a forward region through which the cargo handling device passes is defined, and based on the distance information and the angle information, the highest point of the cargo handling device in the forward region is calculated. In the aforementioned detection area, an obstacle detection area is set in the rear area behind the front area, and the height of the upper end of the obstacle detection area is changed in correlation with the highest point. If the sensor detects an obstacle in the obstacle detection area, the vehicle speed of the vehicle body is limited. A cargo handling vehicle characterized by the following features.

2. The aforementioned sensor unit is It is installed at the upper end of the vehicle body and detects the object by scanning the laser beam vertically. The control unit, The forward region is defined as a first forward region through which the load on the fork and the backrest pass, and a second forward region through which the mast passes. The first highest point of the cargo handling device in the first forward region and the second highest point of the cargo handling device in the second forward region are calculated, and the higher of these two points is taken as the highest point. The cargo handling vehicle according to feature 1.

3. If the first highest point and the second highest point are located on the laser beam at the same angle, The control unit, Based on the distance information and angle information relating to the second highest point, the first highest point is calculated, and the first highest point is set as the highest point. The cargo handling vehicle according to feature 2.

4. The control unit, If the highest point decreases when the aforementioned lifting / lowering operation is not being performed, the height of the upper end of the obstacle detection area is changed. However, if the highest point increases when the aforementioned lifting / lowering operation is not being performed, the height of the upper end of the obstacle detection area is not changed. The cargo handling vehicle according to feature 1.

5. The control unit, The obstacle detection area is set only when the vehicle is moving in reverse. The cargo handling vehicle according to feature 1.

6. The control unit, The obstacle detection area includes multiple regions divided in the front-to-rear direction, and the content of the vehicle speed limit is changed in each region. The cargo handling vehicle according to feature 1.

Images