Forklift

Abstract

To provide a forklift allowing a palette to be properly mounted with respect to a fork.SOLUTION: A forklift comprises: a vehicle body; a fork; a moving apparatus to move the fork in a first direction; a lifting apparatus to raise or lower the fork in a second direction; a tilting apparatus to tilt the fork in the first direction; a sensor to detect that a fork inserting part has approached a facing surface of the inserting hole so close that a distance between the inserting part and the facing surface is less than a prescribed value; and a control device to control the moving apparatus, the lifting apparatus, and the tilting apparatus. The control device executes stopping processing to stop the moving apparatus, the lifting apparatus, and the tilting apparatus at the time detected by the sensor in processing of a step S103. The control device executes avoidance processing to separate the inserting part from the facing surface approached by the inserting part in the processing of a step 104 so that a position in the second direction of the inserting part does not change with respect to an entrance of the inserting hole by controlling the tilting apparatus and the lifting apparatus after the execution of the stopping processing.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a forklift.

Background Art

[0002] Patent Document 1 discloses a forklift. The forklift includes a vehicle body, forks, a tilting device, a lifting device, and a moving device. The forklift includes a first sensor, a second sensor, a third sensor, a fourth sensor, and a controller. A pallet is loaded on the forks. The forks are inserted into the insertion holes of the pallet. The surface forming the insertion holes has a facing surface facing the forks in the thickness direction of the forks. The facing surface has an upper inner surface and a lower inner surface.

[0003] The tilting device is composed of a tilt cylinder, a handling motor, an electromagnetic control valve, and a handling pump. The tilting device tilts the forks forward and backward with respect to the vehicle body. The lifting device is composed of a lift cylinder, a handling motor, an electromagnetic control valve, and a handling pump. The lifting device raises and lowers the forks upward and downward with respect to the vehicle body. The moving device is composed of a reach cylinder, a handling motor, an electromagnetic control valve, and a handling pump. The moving device moves the forks forward and backward with respect to the vehicle body.

[0004] The first sensor and the second sensor are provided at the tip of the forks. The first sensor turns on from off when the distance between the tip of the forks and the upper inner surface becomes a predetermined value or less. The second sensor turns on from off when the distance between the tip of the forks and the lower inner surface becomes a predetermined value or less. The third sensor and the fourth sensor are provided at the base of the forks. The third sensor turns on from off when a load is placed on the base of the forks. The fourth sensor turns on from off when the distance between the base of the forks and the lower inner surface becomes a predetermined value or less.

[0005] The controller executes fork insertion control to insert the fork into the insertion hole based on the detection results of each of the first sensor, second sensor, third sensor, and fourth sensor. In the fork insertion control, avoidance processing is executed. The avoidance processing is executed by the controller when either one of the first sensor and the second sensor is turned on and both the third sensor and the fourth sensor are turned off. The controller raises or lowers the fork by controlling the lifting device in the avoidance processing. By raising or lowering the fork, the fork moves away from the opposing surface of the insertion hole.

[0006] When all of the first sensor, second sensor, third sensor, and fourth sensor are turned off, the controller stops raising or lowering the fork. When the first sensor and the fourth sensor are turned on and the second sensor and the third sensor are turned off, the controller stops lowering the fork. When the first sensor and the fourth sensor are turned off and the second sensor and the third sensor are turned on, the controller stops raising the fork. That is, the avoidance processing is executed or stopped based on the detection results of the first sensor, second sensor, third sensor, and fourth sensor.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] For example, assume a case where the first sensor and the second sensor are located inside the insertion hole and the third sensor and the fourth sensor are located outside the insertion hole. Then, the avoidance processing is executed when either one of the first sensor and the second sensor is turned on, and is stopped when the first sensor and the second sensor are turned off.

[0009] Incidentally, there is a risk that the fork may interfere with the opposing surface of the insertion hole before the avoidance process stops due to the first sensor and the second sensor turning off. Along with this, since the proper insertion of the fork into the insertion hole is inhibited, there is a risk that the pallet cannot be properly loaded onto the fork.

Means for Solving the Problem

[0010] The forklift for solving the above problems includes a vehicle body, a fork on which a pallet is loaded, a moving device that moves the fork in a first direction that includes the forward and backward directions of the vehicle body, a lifting device that raises or lowers the fork in a second direction that is orthogonal to the first direction and includes the upward and downward directions of the vehicle body, a tilting device that tilts the fork with respect to the first direction, a hole into which the fork is inserted when loading the pallet onto the fork is defined as an insertion hole, a portion of the fork that is inserted into the insertion hole is defined as an insertion portion, and a surface of the surface forming the insertion hole that faces the insertion portion in the thickness direction of the insertion portion is defined as an opposing surface. A sensor that is provided in the insertion portion and detects that the insertion portion has approached the opposing surface until the distance between the insertion portion and the opposing surface becomes a predetermined value or less, and a control device that controls the moving device, the lifting device, and the tilting device. The control device performs a stop process of stopping the moving device, the lifting device, and the tilting device when detected by the sensor, and a process executed after the stop process, which is to move the insertion portion away from the opposing surface that the insertion portion has approached so that the position of the insertion portion in the second direction with respect to the entrance of the insertion hole does not change by controlling the tilting device and the lifting device.

[0011] According to this, since the avoidance process is executed after the stop process, the insertion part can be separated from the opposing surface while the mobile device is stopped. In the avoidance process, the insertion part is tilted by controlling the tilting device. As the insertion part tilts, the insertion part moves away from the opposing surface that the insertion part approaches. As the insertion part tilts, the position of the insertion part with respect to the entrance of the insertion hole shifts in the second direction. However, by controlling the lifting device, while separating the insertion part from the opposing surface, the shift can be returned in the second direction. That is, the insertion part can be separated from the opposing surface so that the position of the insertion part in the second direction with respect to the entrance of the insertion hole does not change from before the insertion part tilts. That is, by controlling both the tilting device and the lifting device, the insertion part can be separated from the opposing surface so that the position of the insertion part in the second direction with respect to the entrance of the insertion hole does not change from before the insertion part tilts. Therefore, it is possible to suppress the insertion part from contacting the opposing surface of the insertion hole during the avoidance process. Therefore, appropriate insertion of the fork into the insertion hole can be realized, so that the pallet can be appropriately loaded on the fork.

[0012] In the forklift described above, it is preferable that the control device executes an adjustment process of controlling the lifting device so that the position of the insertion part with respect to the entrance of the insertion hole does not change while inserting the insertion part into the insertion hole after the avoidance process.

[0013] According to this, while inserting the insertion part into the insertion hole, by executing the adjustment process, it becomes possible to insert the insertion part into the insertion hole with the relative position of the insertion part with respect to the insertion hole being changed as little as possible. For this reason, when inserting the insertion part into the insertion hole, it becomes difficult for the insertion part to contact the opposing surface of the insertion hole. Therefore, the frequency at which the stop process is executed by the detection of the sensor can be reduced. Therefore, since the insertion of the insertion part into the insertion hole can be continued as much as possible, the pallet can be smoothly loaded on the fork.

[0014] In the forklift described above, the avoidance process is a first avoidance process executed at the first detection by the sensor. When detecting by the sensor, the control device performs a position grasping process of grasping a first position which is the position of the facing surface in the first direction and a second position which is the position of the facing surface in the second direction. At the first detection by the sensor, the first position is defined as the first first position, and the second position at the first detection by the sensor is defined as the first second position. At the second detection by the sensor, the first position is defined as the second first position, and the second position at the second detection by the sensor is defined as the second second position. A value obtained by dividing the difference between the first second position and the second second position by the difference between the first first position and the second first position is defined as the inclination of the facing surface. When a straight line offset from the facing surface by a predetermined amount so that a virtual straight line having the inclination does not approach the facing surface until the distance between the virtual straight line and the facing surface becomes equal to or less than a predetermined value is set as the target trajectory, after the stop process executed at the second detection by the sensor, a target trajectory calculation process which is a process executed to calculate the target trajectory, and after the target trajectory calculation process, a second avoidance process which arranges the insertion part on the target trajectory by controlling the lifting device and the tilting device, and a maintenance process which maintains the insertion part on the target trajectory by controlling the lifting device while inserting the insertion part into the insertion hole after the second avoidance process may be executed.

[0015] According to this, after the second detection by the sensor is confirmed, the insertion part is inserted into the insertion hole along the target trajectory. Therefore, after the second detection by the sensor, the stop process is not executed by the detection of the sensor. Thus, after the second detection by the sensor, the insertion of the insertion part into the insertion hole can be optimized.

[0016] In the forklift described above, the control device may execute an insertion process of inserting the insertion part into the insertion hole by controlling the moving device. According to this, the insertion of the insertion part into the insertion hole can be automatically executed by the insertion process.

[0017] In the above forklift, the control device may end all processes for inserting the insertion part into the insertion hole when the insertion amount of the insertion part into the insertion hole reaches a specified value.

Effect of the Invention

[0018] According to this invention, the pallet can be appropriately loaded onto the fork.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

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Figure 10

Figure 11

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Figure 14

Figure 15

Mode for Carrying Out the Invention

[0020] [First Embodiment] Hereinafter, a first embodiment in which a forklift is embodied will be described with reference to FIGS. 1 to 11.

[0021] <Configuration of Forklift> As shown in FIG. 1, the forklift 10 is used in a workplace where it is necessary to transport the pallet P in factories, ports, airports, commercial facilities, etc. After performing a loading and unloading operation of loading the pallet P, the forklift 10 transports the pallet P. The pallet P includes a rectangular box-shaped storage portion S for storing the transported object and legs L provided at the four corners of the storage portion S. The pallet P is a mesh pallet. The forklift 10 of the present embodiment is a reach-type forklift.

[0022] The forklift 10 includes a vehicle body 11, a reach leg 12, front wheels 13, rear wheels 14, a traveling motor 15, a loading and unloading device 20, and a control device 30. In the following description, the direction including the front direction and the rear direction of the vehicle body 11 is defined as the first direction A, the direction including the upward direction and the downward direction of the vehicle body 11 is defined as the second direction B, and the direction including the left direction and the right direction of the vehicle body 11 is defined as the third direction C. The first direction A and the second direction B are orthogonal to each other. The first direction A and the third direction C are orthogonal to each other.

[0023] The reach leg 12 extends forward from the vehicle body 11 in the forward direction of the vehicle body 11. Two reach legs 12 are provided at intervals in the third direction C. The front wheels 13 are provided on each of the pair of reach legs 12. The rear wheels 14 are provided on the vehicle body 11. The rear wheels 14 are, for example, steering wheels and drive wheels driven by a traveling motor 15. When the traveling motor 15 is driven, the forklift 10 moves in the first direction A.

[0024] The handling device 20 has a mast 21, a lift bracket 22, and forks 23. The handling device 20 has a reach cylinder 24, a lift cylinder 25, a tilt cylinder 26, and a hydraulic mechanism 40.

[0025] The mast 21 is a multi-stage mast. Two masts 21 are provided at intervals in the third direction C. The mast 21 is configured by slidably engaging an outer mast, a middle mast, and an inner mast. A carriage including the lift bracket 22 and the forks 23 is provided on the mast 21. The carriage is suspended from the inner mast of the mast 21 via a chain mechanism (not shown).

[0026] The lift bracket 22 is provided between the pair of masts 21 so as to be able to move up and down in the second direction B. Two forks 23 are provided at intervals in the third direction C. The reach cylinder 24 is a hydraulic cylinder. The mast 21 moves in the first direction A by supplying and discharging hydraulic oil to the reach cylinder 24. The forks 23 move in the first direction A together with the mast 21. The movement of the mast 21 and the forks 23 forward of the vehicle body 11 by the reach cylinder 24 is called reach out.

[0027] The lift cylinder 25 is a hydraulic cylinder. The lift bracket 22 rises or falls in the second direction B along the mast 21 with the expansion and contraction of the mast 21 by supplying and discharging hydraulic oil to the lift cylinder 25. The forks 23 rise or fall in the second direction B together with the lift bracket 22.

[0028] The tilt cylinder 26 is a hydraulic cylinder. The carriage includes a finger bar (not shown) attached to the lift bracket 22. The finger bar tilts in the first direction A by the supply and discharge of hydraulic oil to the tilt cylinder 26. The lift bracket 22 also tilts together with the finger bar. The tilting includes a forward tilt that tilts the lift bracket 22 forward with respect to the vehicle body 11 and a backward tilt that tilts the lift bracket 22 backward with respect to the vehicle body 11. The fork 23 tilts together with the lift bracket 22.

[0029] As shown in FIG. 3, the hydraulic mechanism 40 is a mechanism for controlling the supply and discharge of hydraulic oil to hydraulic devices including the reach cylinder 24, the lift cylinder 25, and the tilt cylinder 26. The hydraulic mechanism 40 has a control valve 41, a handling pump 42, and a handling motor 43. The control valve 41 controls the supply and discharge of hydraulic oil to the reach cylinder 24, the lift cylinder 25, and the tilt cylinder 26. The control valve 41 is an electromagnetic control valve that adjusts the opening degree of the oil passage for supplying and discharging hydraulic oil to the reach cylinder 24, the lift cylinder 25, and the tilt cylinder 26. The handling pump 42 discharges hydraulic oil to the control valve 41. The handling motor 43 generates power to drive the handling pump 42.

[0030] As shown in FIGS. 1 and 3, the traveling motor 15, the reach cylinder 24, and the hydraulic mechanism 40 are an example of a moving device that moves the fork 23 in the first direction A. The lift cylinder 25 and the hydraulic mechanism 40 are an example of a lifting device that raises or lowers the fork 23 in the second direction B. The tilt cylinder 26 and the hydraulic mechanism 40 are an example of a tilting device that tilts the fork 23 with respect to the first direction A.

[0031] As shown in FIGS. 1 and 2, the forklift 10 includes an operation unit 16 that can be operated by an operator boarding the forklift 10. The operation unit 16 includes a reach operation unit 161, a lift operation unit 162, a tilt operation unit 163, and an accelerator operation unit 164.

[0032] The reach operation unit 161 includes a reach lever that can be tilted forward or backward from the neutral position in the first direction A by an operator of the forklift 10. When the reach lever is tilted forward from the neutral position in the forward direction of the vehicle body 11, the reach operation unit 161 outputs a signal to the control device 30. When this signal is output, the fork 23 moves in the forward direction of the vehicle body 11 together with the mast 21. When the reach lever is tilted backward from the neutral position in the rearward direction of the vehicle body 11, the reach operation unit 161 outputs a signal to the control device 30. When this signal is output, the fork 23 moves in the rearward direction of the vehicle body 11 together with the mast 21.

[0033] The lift operation unit 162 includes a lift lever that can be tilted forward or backward from the neutral position in the first direction A by an operator of the forklift 10. When the lift lever is tilted forward from the neutral position in the forward direction of the vehicle body 11, the lift operation unit 162 outputs a signal to the control device 30. When this signal is output, the fork 23 descends together with the lift bracket 22. When the lift lever is tilted backward from the neutral position in the rearward direction of the vehicle body 11, the lift operation unit 162 outputs a signal to the control device 30. When this signal is output, the fork 23 ascends together with the lift bracket 22.

[0034] The tilt operation unit 163 includes a tilt lever that can be tilted forward or backward from the neutral position in the first direction A by an operator of the forklift 10. When the tilt lever is tilted forward from the neutral position in the forward direction of the vehicle body 11, the tilt operation unit 163 outputs a signal to the control device 30. When this signal is output, the lift bracket 22 tilts forward with respect to the first direction A. When the tilt lever is tilted backward from the neutral position in the rearward direction of the vehicle body 11, the tilt operation unit 163 outputs a signal to the control device 30. When this signal is output, the lift bracket 22 tilts backward with respect to the first direction A.

[0035] The accelerator operation unit 164 includes an accelerator lever that can be tilted forward or backward from the neutral position in the first direction A by the operator of the forklift 10. When the accelerator lever is tilted forward from the neutral position in the forward direction of the vehicle body 11, the accelerator operation unit 164 outputs a signal to the control device 30. When this signal is output, the travel motor 15 is driven so that the forklift 10 moves forward. When the accelerator lever is tilted backward from the neutral position in the rear direction of the vehicle body 11, the accelerator operation unit 164 outputs a signal to the control device 30. When this signal is output, the travel motor 15 is driven so that the forklift 10 moves backward.

[0036] As shown in FIGS. 4 and 5, the forklift 10 performs a loading / unloading operation on the pallet P loaded on the truck T. The stop position A1 of the truck T is predetermined. The forklift 10 executes the loading / unloading operation after moving to the loading / unloading position A2. The truck T includes a loading platform TB, a side tilt SS, a rear tilt RS, and tires T1. The pallet P is loaded on the loading platform TB. The side tilt SS is provided on the side portion of the loading platform TB. The side tilt SS is rotatable in the upward and downward directions of the truck T. The rear tilt RS is provided at the rear portion of the loading platform TB. The rear tilt RS is rotatable in the upward and downward directions of the truck T. During the travel of the truck T, etc., the loading platform TB is surrounded by the side tilt SS and the rear tilt RS. When the forklift 10 performs the loading / unloading operation, the side tilt SS and the rear tilt RS are rotated downward, and the side tilt SS and the rear tilt RS do not face the pallet P. That is, when the forklift 10 performs the loading / unloading operation, the side tilt SS and the rear tilt RS are rotated so as not to interfere with the loading / unloading operation by the forklift 10.

[0037] As shown in FIG. 5, an insertion hole IH, which is a hole surrounded by the loading platform TB, the leg portion L, and the storage portion S, is formed in a state where the pallet P is loaded on the loading platform TB. The insertion hole IH is a hole into which the fork 23 of the forklift 10 is inserted when loading the pallet P on the fork 23. The forklift 10 performs a cargo handling operation from the side sway SS side of the truck T. After the fork 23 is inserted into the insertion hole IH, when the pallet P is loaded on the fork 23, the cargo handling operation is completed. The fork 23 has an insertion portion 231 which is a portion inserted into the insertion hole IH.

[0038] As shown in FIG. 1, the insertion portion 231 of the fork 23 supports the bottom of the storage portion S. The insertion portion 231 has a plate shape. The insertion portion 231 has a first surface 231a facing the bottom of the storage portion S and a second surface 231b located on the side opposite to the first surface 231a in the thickness direction of the insertion portion 231.

[0039] As shown in FIG. 3, the forklift 10 includes an auxiliary storage device 50, a first sensor 51, a second sensor 52, and a vehicle speed sensor 53. The forklift 10 includes a reach sensor 54, a lift sensor 55, a tilt sensor 56, and an environment sensor 57.

[0040] The auxiliary storage device 50 stores information that can be read by the control device 30. As the auxiliary storage device 50, for example, a hard disk drive or a solid state drive is used. Map information is stored in the auxiliary storage device 50. The map information is information regarding the physical structure of the surrounding environment of the forklift 10, such as the shape and size of the environment in which the forklift 10 is used. Positions such as the parking position A1 and the loading / unloading position A2 are represented as coordinates in the map information. The map information is data indicating the environment in which the forklift 10 is used in coordinates. The map information may be stored in the auxiliary storage device 50 in advance if the surrounding environment in which the forklift 10 is used can be grasped in advance. When storing the map information in the auxiliary storage device 50 in advance, coordinates of objects that do not easily change in position, such as walls and pillars of a building, are stored as the map information. The map information may be created by mapping using SLAM: Simultaneous Localization and Mapping. The mapping is performed, for example, by creating a local map from the coordinates obtained by the environment sensor 57 and combining this local map according to the self-position of the forklift 10. The environment sensor 57 is a sensor that can cause the control device 30 to recognize the relative position between an object located behind the forklift 10 and the forklift 10. As the environment sensor 57, for example, a millimeter wave radar, a stereo camera, LIDAR: Laser Imaging Detection and Ranging, etc. can be used.

[0041] The first sensor 51 and the second sensor 52 are provided at the tip of the insertion portion 231 of the fork 23. The first sensor 51 and the second sensor 52 are embedded in the insertion portion 231. The first sensor 51 is provided closer to the first surface 231a in the thickness direction of the insertion portion 231. The second sensor 52 is provided closer to the second surface 231b in the thickness direction of the insertion portion 231. Among the surfaces forming the insertion hole IH, the surface facing the insertion portion 231 in the thickness direction of the insertion portion 231 is defined as the opposing surface. The opposing surface has a first opposing surface IH1 facing the first surface 231a of the insertion portion 231 and a second opposing surface IH2 facing the second surface 231b of the insertion portion 231. The first opposing surface IH1 is the surface of the accommodating portion S facing the loading platform TB. The second opposing surface IH2 is the upper surface of the loading platform TB.

[0042] The first sensor 51 and the second sensor 52 are, for example, reflective photoelectric sensors. The first sensor 51 outputs a signal S1 to the control device 30 when the distance from the first opposing surface IH1 becomes equal to or less than a predetermined value. The second sensor 52 outputs a signal S2 to the control device 30 when the distance from the second opposing surface IH2 becomes equal to or less than a predetermined value. The first sensor 51 and the second sensor 52 are sensors that detect that the insertion portion 231 has approached the opposing surface. Note that the first sensor 51 and the second sensor 52 may be changed to any one of a proximity sensor, a distance sensor, a limit switch, a force sensor, and a contact sensor.

[0043] The vehicle speed sensor 53 outputs a signal SV corresponding to the vehicle speed when the forklift 10 is running to the control device 30. The reach sensor 54 outputs a signal Sr corresponding to the moving amount Pr by which the mast 21 has moved by the reach cylinder 24 to the control device 30. The lift sensor 55 outputs a signal SL corresponding to the height PL of the fork 23 that has been raised or lowered by the lift cylinder 25 to the control device 30. The tilt sensor 56 outputs a signal Sθ corresponding to the tilt angle θ of the lift bracket 22 tilted by the tilt cylinder 26 to the control device 30. The tilt angle θ is the inclination angle of the lift bracket 22 with respect to the first direction A.

[0044] <Configuration of the control device> As shown in FIG. 3, the control device 30 includes a processor 31 such as a CPU or GPU, and a storage unit 32 composed of a RAM, a ROM, and the like. The storage unit 32 stores program codes or instructions configured to cause the processor 31 to execute processing. The storage unit 32, that is, the computer-readable medium, includes any available medium accessible by a general-purpose or dedicated computer. The control device 30 may be configured by a hardware circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). The control device 30, which is a processing circuit, may include one or more processors operating according to a computer program, one or more hardware circuits such as an ASIC or an FPGA, or a combination thereof.

[0045] The control device 30 controls the traveling motor 15 and the hydraulic mechanism 40 according to the program stored in the storage unit 32. As a result, the forklift 10 travels, and the reach cylinder 24, the lift cylinder 25, and the tilt cylinder 26 operate. Therefore, it can be said that the control device 30 controls the moving device, the lifting device, and the tilting device. The forklift 10 of the present embodiment is not operated by an operator. The forklift 10 is a forklift that automatically operates by the control of the moving device, the lifting device, and the tilting device by the control device 30. Note that the program codes and instructions stored in the storage unit 32 may be stored in the auxiliary storage device 50 instead of the storage unit 32.

[0046] The control device 30 executes self-position estimation processing. The self-position estimation processing is processing for estimating the self-position of the forklift 10 on the map information stored in the auxiliary storage device 50. The control device 30 can move the forklift 10 to the loading / unloading position A2 by controlling the travel motor 15 while executing the self-position estimation processing. The self-position estimation processing may be performed, for example, using odometry that estimates the amount of self-movement using the rotation speed of the travel motor 15, or may be performed from the matching result between the landmark and the map information. Also, the self-position estimation processing may be executed by combining these. If the environment in which the forklift 10 is used is outdoors, the self-position may be estimated using GPS: Global Positioning System. Note that the self-position is the coordinates indicating a point on the vehicle body 11, for example, the coordinates at the center in the horizontal direction of the vehicle body 11.

[0047] The forklift 10 can adjust the height of the fork 23 so that the insertion hole IH and the tip of the insertion portion 231 face each other when reaching the loading / unloading position A2. The control device 30 moves the fork 23 in the first direction A by advancing the forklift 10 from the loading / unloading position A2 or extending the mast 21. Thereby, the insertion portion 231 is inserted into the insertion hole IH. The control device 30 executes processing for appropriately inserting the insertion portion 231 into the insertion hole IH when the forklift 10 performs a loading / unloading operation. Note that the processing for appropriately inserting the insertion portion 231 into the insertion hole IH will be described in detail later.

[0048] The control device 30 includes a fork insertion control unit 33 and a command value calculation unit 34. Signals S1, S2, SV, Sr, SL, and Sθ are input to the fork insertion control unit 33. Based on the signals S1, S2, SV, Sr, SL, and Sθ, the fork insertion control unit 33 calculates the voltage values Prv, PLv, θv, and PVv of the signals output by the operation unit 16 in an analog manner. The fork insertion control unit 33 calculates the voltage values Prv, PLv, θv, and PVv assuming the case where the operation unit 16 is operated by the occupant based on the signals S1, S2, SV, Sr, SL, and Sθ. The voltage value Prv is a value simulating the voltage value of the signal output from the reach operation unit 161. The voltage value PLv is a value simulating the voltage value of the signal output from the lift operation unit 162. The voltage value θv is a value simulating the voltage value of the signal output from the tilt operation unit 163. The voltage value PVv is a value simulating the voltage value of the signal output from the accelerator operation unit 164. The fork insertion control unit 33 outputs signals having the respective voltage values Prv, PLv, θv, and PVv to the command value calculation unit 34.

[0049] <Configuration of Fork Insertion Control Unit> As shown in FIG. 3, the fork insertion control unit 33 includes a proximity detection unit 33a, a position and orientation calculation unit 33b, and a target position and orientation calculation unit 33c.

[0050] The signal S1 of the first sensor 51 and the signal S2 of the second sensor 52 are input to the proximity detection unit 33a. When only the signal S1 is input, the proximity detection unit 33a determines that the insertion unit 231 has approached the first facing surface IH1 until the distance between the first surface 231a of the insertion unit 231 and the first facing surface IH1 becomes equal to or less than a predetermined value. This determination result is taken as the first result.

[0051] When only the signal S2 is input, the proximity detection unit 33a determines that the insertion unit 231 has approached the second facing surface IH2 until the distance between the second surface 231b of the insertion unit 231 and the second facing surface IH2 becomes equal to or less than a predetermined value. This determination result is taken as the second result.

[0052] When the signals S1 and S2 are not input, the approach detection unit 33a determines that the insertion unit 231 has not approached the opposing surface of the insertion hole IH until the distance between the insertion unit 231 and the opposing surface of the insertion hole IH becomes equal to or less than a predetermined value. This determination result is taken as the third result.

[0053] When both the signals S1 and S2 are input, the approach detection unit 33a determines that an abnormality has occurred in the first sensor 51 and the second sensor 52. This determination result is taken as the fourth result. The approach detection unit 33a outputs the determination result to the target position and orientation calculation unit 33c.

[0054] The signals SV, Sr, SL, and Sθ are input to the position and orientation calculation unit 33b. The position and orientation calculation unit 33b calculates the movement amount Pr of the mast 21 based on the signal Sr. The position and orientation calculation unit 33b calculates the height PL of the fork 23 based on the signal SL. The position and orientation calculation unit 33b calculates the tilt angle θ of the lift bracket 22 based on the signal Sθ. The position and orientation calculation unit 33b calculates the vehicle speed of the forklift 10 based on the signal SV, and calculates the movement amount PV of the forklift 10 based on the vehicle speed. The position and orientation calculation unit 33b outputs the movement amount Pr, the height PL, the tilt angle θ, and the movement amount PV to the target position and orientation calculation unit 33c.

[0055] The determination result output from the approach detection unit 33a and the movement amount Pr, the height PL, the tilt angle θ, and the movement amount PV output from the position and orientation calculation unit 33b are input to the target position and orientation calculation unit 33c.

[0056] The target position and orientation calculation unit 33c calculates the target mast position Pr*. The target mast position Pr* is the target position at which the mast 21 should be located in the first direction A based on the input determination result and the movement amount Pr. The target position and orientation calculation unit 33c calculates the voltage value Prv. The voltage value Prv is an analog representation of the voltage value of the signal output from the reach operation unit 161 when the reach operation unit 161 is operated to achieve the target mast position Pr*. The target position and orientation calculation unit 33c outputs a signal having the voltage value Prv to the command value calculation unit 34.

[0057] The target position and orientation calculation unit 33c calculates the target fork height PL*. The target fork height PL* is the target position where the fork 23 should be located in the second direction B based on the input determination result and the height PL. The target position and orientation calculation unit 33c calculates the voltage value PLv. The voltage value PLv is an analog representation of the voltage value of the signal output from the lift operation unit 162 when the lift operation unit 162 is operated to achieve the target fork height PL*. The target position and orientation calculation unit 33c outputs a signal having the voltage value PLv to the command value calculation unit 34.

[0058] The target position and orientation calculation unit 33c calculates the target tilt angle θ*. The target tilt angle θ* is the target tilt angle of the lift bracket 22 with respect to the first direction A based on the input determination result and the tilt angle θ. The target position and orientation calculation unit 33c calculates the voltage value θv. The voltage value θv is an analog representation of the voltage value of the signal output from the tilt operation unit 163 when the tilt operation unit 163 is operated to achieve the target tilt angle θ*. The target position and orientation calculation unit 33c outputs a signal having the voltage value θv to the command value calculation unit 34.

[0059] The target position and orientation calculation unit 33c calculates the target vehicle position PV*. The target vehicle position PV* is the target position where the forklift 10 should be located in the first direction A based on the input determination result and the movement amount PV. The target position and orientation calculation unit 33c calculates the voltage value PVv. The voltage value PVv is an analog representation of the voltage value of the signal output from the accelerator operation unit 164 when the accelerator operation unit 164 is operated to achieve the target vehicle position PV*. The target position and orientation calculation unit 33c outputs a signal having the voltage value PVv to the command value calculation unit 34.

[0060] <Command value calculation unit> A signal having voltage values Prv, PLv, θv, and PVv is input to the command value calculation unit 34. The command value calculation unit 34 calculates command values for driving the traveling motor 15, the control valve 41, and the handling motor 43 based on the signal having the voltage values Prv, PLv, θv, and PVv. The command value is a value indicating the output ratio of the traveling motor 15, the control valve 41, and the handling motor 43. The command value calculation unit 34 outputs a signal of the voltage value for realizing the command value to the traveling motor 15, the control valve 41, and the handling motor 43. The traveling motor 15, the control valve 41, and the handling motor 43 are controlled by the signal output from the command value calculation unit 34. When the operation unit 16 is operated by the operator of the forklift 10, the command value calculation unit 34 calculates the command values of the traveling motor 15, the control valve 41, and the handling motor 43 based on the voltage value of the signal output from the operation unit 16.

[0061] (Processing for appropriately inserting the insertion part into the insertion hole) As shown in FIG. 6, when the process for appropriately inserting the insertion part 231 into the insertion hole IH is started, the control device 30 executes the insertion process in step S101. The insertion process is a process in which the control device 30 controls the moving device to insert the insertion part 231 of the fork 23 into the insertion hole IH. The process for appropriately inserting the insertion part 231 into the insertion hole IH is started with the insertion part 231 extending in the first direction A. Further, the process for appropriately inserting the insertion part 231 into the insertion hole IH is started with the mast 21 not in the reach-out state. When the control device 30 executes the process of step S101, the process proceeds to step S102.

[0062] The control device 30 determines whether the insertion part 231 has approached the first opposing surface IH1 in the process of step S102. The process of step S102 is executed by the approach detection unit 33a. When the control device 30 determines in the process of step S102 that the insertion part 231 has approached the first opposing surface IH1 (step S102: YES), the process proceeds to step S103. The case where it is determined in the process of step S102 that the insertion part 231 has approached the first opposing surface IH1 (step S102: YES) is the case where the first result is output from the approach detection unit 33a.

[0063] The control device 30 executes a stop process in the process of step S103. When the control device 30 executes the process of step S103, the process proceeds to step S104. The control device 30 executes an avoidance process in the process of step S104. When the control device 30 executes the process of step S104, the process returns to step S102 again.

[0064] When the control device 30 determines in the process of step S102 that the insertion part 231 has not approached the first opposing surface IH1 (step S102: NO), the process proceeds to step S105.

[0065] The control device 30 determines whether the insertion part 231 has approached the second opposing surface IH2 in the process of step S105. The process of step S105 is executed by the approach detection unit 33a. When the control device 30 determines in the process of step S105 that the insertion part 231 has approached the second opposing surface IH2 (step S105: YES), the process proceeds to step S103. The case where it is determined in the process of step S105 that the insertion part 231 has approached the second opposing surface IH2 (step S105: YES) is the case where the second result is output from the approach detection unit 33a.

[0066] When the control device 30 determines in the process of step S105 that the insertion part 231 is not approaching the second facing surface IH2 (step S105: NO), the process proceeds to step S106. Here, the cases where NO is determined in the processes of steps S102 and S105 are the cases where the third result is output from the approach detection unit 33a. Note that the case where YES is determined in both the process of step S102 and the process of step S105 is the case where the fourth result is output from the approach detection unit 33a. Although not shown in FIG. 6, when the fourth result is output from the approach detection unit 33a, the process for appropriately inserting the insertion part 231 into the insertion hole IH is terminated.

[0067] The control device 30 determines whether it is after executing the avoidance process in the process of step S106. The control device 30 determines whether the tilt angle θ calculated by the position and attitude calculation unit 33b in the process of step S106 is "0". When the control device 30 determines that it is not after executing the avoidance process in the process of step S106 (step S106: NO), the process proceeds to step S107. That is, when the control device 30 determines that it is before executing the avoidance process (step S106: NO), the process proceeds to step S107. The control device 30 determining that it is not after executing the avoidance process (step S106: NO) is synonymous with the control device 30 determining that the tilt angle θ calculated by the position and attitude calculation unit 33b is "0". The control device 30 executes the insertion process in the process of step S107. This is synonymous with the control device 30 continuing the insertion process executed in the process of step S101. When the control device 30 executes the process of step S107, the process proceeds to step S108.

[0068] When the control device 30 determines that it is after executing the avoidance process in the process of step S106 (step S106: YES), the process proceeds to step S109. That is, when the control device 30 determines that the tilt angle θ calculated by the position and attitude calculation unit 33b is not "0" (step S106: NO), the process proceeds to step S109.

[0069] In step S109, the control device 30 determines whether the fork 23 is tilted forward together with the lift bracket 22. The control device 30 determines whether the tilt angle θ calculated by the position and attitude calculation unit 33b is less than "0". When the control device 30 determines that the fork 23 is tilted forward in the process of step S109 (step S109: YES), the process proceeds to step S110. In other words, when the control device 30 determines that the tilt angle θ calculated by the position and attitude calculation unit 33b is less than "0" in the process of step S109 (step S109: YES), the process proceeds to step S110.

[0070] When the control device 30 determines that the fork is not tilted forward in the process of step S109 (step S109: NO), the process proceeds to step S111. In other words, when the control device 30 determines that the tilt angle θ calculated by the position and attitude calculation unit 33b is greater than "0" in the process of step S109 (step S109: NO), the process proceeds to step S111.

[0071] The control device 30 simultaneously executes the insertion process and the adjustment process in the processes of step S110 and step S111. The adjustment process executed in the process of step S110 is a process of raising the fork 23 by controlling the lifting device. The adjustment process executed in the process of step S111 is a process of lowering the fork 23 by controlling the lifting device. When the control device 30 executes the process of step S110 or step S111, the process proceeds to step S108.

[0072] In step S108, the control device 30 determines whether the insertion amount Din of the insertion portion 231 into the insertion hole IH is equal to or greater than the specified value Dth. The insertion amount Din indicates the length by which the insertion portion 231 is inserted into the insertion hole IH. The control device 30 calculates the insertion amount Din.

[0073] The control device 30 calculates the insertion amount Din based on the moving amount PV of the forklift 10 from the loading position A2, the extended moving amount Pr of the mast 21, and the tilt angle θ of the lift bracket 22. When the insertion portion 231 is inserted into the insertion hole IH in a state where the insertion portion 231 always extends in the first direction A, the insertion amount Din is the sum of the moving amount PV of the forklift 10 and the moving amount Pr of the mast 21.

[0074] When the insertion portion 231 is inserted into the insertion hole IH in a state where the lift bracket 22 is tilted with respect to the first direction A, the insertion amount Din is calculated in consideration of the moving amount PV of the forklift 10, the moving amount Pr of the mast 21, and the tilt angle θ. Assume that the insertion process is executed multiple times. In this case, the insertion amount Din is calculated by adding up the insertion amounts of the insertion portion 231 into the insertion hole IH calculated in consideration of the tilt angle θ for each insertion process, the number of times the insertion process is executed. The specified value Dth is stored in the storage unit 32.

[0075] When the control device 30 determines in the process of step S108 that the insertion amount Din is not greater than or equal to the specified value Dth (step S108: NO), the process returns to step S102 again. When the control device 30 determines in the process of step S108 that the insertion amount Din is greater than or equal to the specified value Dth (step S108: YES), all the processes for inserting the insertion portion 231 into the insertion hole IH are terminated.

[0076] (Regarding the stop process, avoidance process, and adjustment process) As shown in FIG. 7, in the loading and unloading operation, when the loading platform TB of the truck T is not inclined with respect to the first direction A, after the insertion portion 231 is inserted into the insertion hole IH, the insertion process continues without being stopped until the insertion amount Din becomes equal to or greater than the specified value Dth. When the insertion amount Din of the insertion portion 231 into the insertion hole IH becomes equal to or greater than the specified value Dth, the insertion process stops. That is, all the processes for inserting the insertion portion 231 into the insertion hole IH are completed. In this case, the control flow of the control device 30 results in a NO determination in the processes of steps S102, S105, and S106, and after the insertion process is continued by step S107, a YES determination is made in the process of step S108. For convenience of explanation, FIG. 7 shows the insertion portion 231 of the fork 23 and the insertion hole IH, and the illustration of the entire forklift 10 is omitted.

[0077] In the loading and unloading operation, when the loading platform TB of the truck T is inclined with respect to the first direction A, when the insertion portion 231 is inserted into the insertion hole IH by step S101, a YES determination is made in the process of step S102 or step S105. In this case, a stop process is executed in the process of step S103.

[0078] The stop process is a process of stopping the moving device, the lifting device, and the tilting device when the insertion portion 231 approaches the first opposing surface IH1 until the distance between the insertion portion 231 and the first opposing surface IH1 becomes equal to or less than a predetermined value by the first sensor 51. The stop process is also a process of stopping the moving device, the lifting device, and the tilting device when the insertion portion 231 approaches the second opposing surface IH2 until the distance between the insertion portion 231 and the second opposing surface IH2 becomes equal to or less than a predetermined value by the second sensor 52.

[0079] The stop process is a process of stopping the mobile device, the lifting device, and the tilting device when detected by the first sensor 51 and the second sensor 52. The stop process is a process of stopping the operations of the traveling motor 15, the control valve 41, and the handling motor 43 when the first result or the second result is output from the approach detection unit 33a. In the stop process, the target position and attitude calculation unit 33c outputs each signal having the voltage values PVv, Prv, PLv, θv necessary for the traveling motor 15, the control valve 41, and the handling motor 43 to stop.

[0080] The avoidance process is a process executed after the stop process. A situation where the loading platform TB inclines closer to the ground as it moves away from the fork 23 in the first direction A shown in FIGS. 8 and 9 is defined as the first situation. Hereinafter, the avoidance process in the first situation will be described.

[0081] As shown in FIGS. 8 and 9, the avoidance process in the first situation is a process of tilting the insertion part 231 in the forward direction of the forklift 10 and then raising the insertion part 231 in the second direction B. For convenience of explanation, FIGS. 8 and 9 show the fork 23 and the insertion hole IH, and the illustration of the entire forklift 10 is omitted.

[0082] As shown in FIG. 10, the control device 30 first executes the process of step S201 in the avoidance process. The control device 30 calculates the target tilt angle θ※ in the process of step S201. The process of step S201 is executed by the target position and attitude calculation unit 33c. The control device 30 calculates the target tilt angle θ※ by adding the angle Δθ to the tilt angle θ output from the position and attitude calculation unit 33b in the process of step S201. The angle Δθ is a fixed value. The angle Δθ is, for example, -1°. This fixed value is an angle set after confirming in advance that the distance between the insertion part 231 and the first opposing surface IH1 becomes larger than a predetermined value. This fixed value is an angle set after confirming in advance that the distance between the insertion part 231 and the second opposing surface IH2 becomes larger than a predetermined value. When the control device 30 executes the process of step S201, it proceeds to the process of step S202.

[0083] The control device 30 calculates a command value for operating the tilting device in the process of step S202. The control device 30 calculates command values for the control valve 41 and the handling motor 43 that realize the target tilt angle θ* calculated in the process of step S201 in the process of step S202. When the control device 30 executes the process of step S202, it advances the process to step S203.

[0084] The control device 30 operates the tilt cylinder 26 by outputting a signal of a voltage value that realizes the command value calculated in the process of step S202 to the control valve 41 and the handling motor 43 in the process of step S203. That is, the control device 30 tilts the fork 23 forward by controlling the tilting device in the process of step S203. The processes of steps S202 and S203 are executed by the command value calculation unit 34. When the control device 30 executes the process of step S203, it advances the process to step S204.

[0085] The control device 30 determines whether or not the target tilt angle θ* calculated in the process of step S201 has been achieved in the process of step S204. The process of step S204 is executed by the target position and orientation calculation unit 33c. In the process of step S204, the control device 30 determines whether or not the tilt angle θ output from the position and orientation calculation unit 33b based on the signal Sθ output from the tilt sensor 56 matches the target tilt angle θ*.

[0086] If the control device 30 determines in the process of step S204 that the target tilt angle θ* has not been achieved (step S204: NO), it continues the process of step S203. That is, the signal output from the command value calculation unit 34 to the control valve 41 and the handling motor 43 in the process of step S203 continues to be output until the target tilt angle θ* is achieved. If the control device 30 determines in the process of step S204 that the target tilt angle θ* has been achieved (step S204: YES), it advances the process to step 205.

[0087] The control device 30 stops the tilting device in the process of step S205. The control device 30 generates a signal of the voltage value θv required by the control valve 41 and the handling motor 43 in order to stop the operation of the tilt cylinder 26 in the process of step S205 by the target position and attitude calculation unit 33c. The control device 30 outputs the signal of the voltage value θv generated in the process of step S205 to the command value calculation unit 34 to stop the tilting device. When the control device 30 executes step S205, it advances the process to step S206.

[0088] When the processes of steps S201, S202, S203, S204, and S205 are executed, as shown by the two-dot chain line in FIG. 8, the insertion part 231 moves away from the first opposing surface IH1 so that the distance between the first surface 231a of the insertion part 231 and the first opposing surface IH1 becomes larger than a predetermined value. By executing steps S201, S202, S203, S204, and S205, the position SP of the insertion part 231 at the inlet IHin of the insertion hole IH drops by a specified amount Δh. The position SP is, for example, the position of the first surface 231a of the insertion part 231 at the inlet IHin of the insertion hole IH. The position SP may be the position of the second surface 231b of the insertion part 231 at the inlet IHin of the insertion hole IH. The position SP may be the position of any part of the insertion part 231 at the inlet IHin of the insertion hole IH.

[0089] As shown in FIG. 10, the control device 30 calculates the target fork height PL* in the process of step S206. The process of step S206 is executed by the target position and attitude calculation unit 33c. The control device 30 calculates the target fork height PL* by adding the specified amount Δh to the height PL of the fork 23 output from the position and attitude calculation unit 33b in the process of step S206.

[0090] The specified amount Δh is calculated by the control device 30. The position of the insertion part 231 when the stop process is executed is fixed. Also, the position of the insertion part 231 when the stop process is executed is a position tilted only by an angle Δθ, which is a fixed value, with respect to the first direction A. Therefore, the specified amount Δh can be calculated as the deviation amount between the position SP of the insertion part 231 when the stop process is executed and the position SP when the insertion part 231 is rotated by the angle Δθ. When the control device 30 executes the process of step S206, the process proceeds to the process of step S207.

[0091] The control device 30 calculates a command value for operating the lifting device in the process of step S207. The control device 30 calculates command values for the control valve 41 and the handling motor 43 that realize the target fork height PL※ calculated in the process of step S206 in the process of step S207. When the control device 30 executes the process of step S207, the process proceeds to step S208.

[0092] The control device 30 operates the lift cylinder 25 by outputting a signal of a voltage value that realizes the command value calculated in the process of step S207 to the control valve 41 and the handling motor 43 in the process of step S208. That is, the control device 30 raises the fork 23 by controlling the lifting device in the process of step S208. The processes of steps S207 and S208 are executed by the command value calculation unit 34. When the control device 30 executes the process of step S208, the process proceeds to step S209.

[0093] The control device 30 determines whether or not the target fork height PL※ calculated in the process of step S206 is achieved in the process of step S209. The process of step S209 is executed by the target position and attitude calculation unit 33c. In the process of step S209, the control device 30 determines whether or not the height PL of the fork 23 output from the target position and attitude calculation unit 33c based on the signal SL of the lift sensor 55 matches the target fork height PL※.

[0094] When the control device 30 determines in the process of step S209 that the target fork height PL* has not been achieved (step S209: NO), the process of step S208 is continued. That is, in the process of step S208, the signals output from the command value calculation unit 34 to the control valve 41 and the handling motor 43 continue to be output until the target fork height PL* is achieved. When the control device 30 determines in the process of step S209 that the target fork height PL* has been achieved (step S209: YES), the process proceeds to step 210.

[0095] The control device 30 stops the lifting device in the process of step S210. The control device 30 generates a signal of the voltage value PLv required by the control valve 41 and the handling motor 43 to stop the operation of the lift cylinder 25 in the process of step S210 by the target position and attitude calculation unit 33c. The control device 30 stops the lifting device by outputting the signal of the voltage value PLv generated in the process of step S210 to the command value calculation unit 34. When the control device 30 executes step S210, the avoidance process ends, and the process of step S102 shown in FIG. 6 is executed again.

[0096] When the processes of steps S206, S207, S208, S209, and S210 are executed, as shown by the dashed two-dot line in FIG. 9, the position SP of the insertion part 231 returns to the position SP of the insertion part 231 before the avoidance process is executed. When the processes of steps S206, S207, S208, S209, and S210 are executed, the inclination of the insertion part 231 with respect to the first opposing surface IH1 and the second opposing surface IH2 becomes gentler than before the avoidance process is executed.

[0097] In the first direction A, a situation where the loading platform TB is inclined so as to be farther from the ground as it moves away from the forklift 10 is defined as the second situation. Even in the second situation, the same avoidance process as the avoidance process in the first situation is executed.

[0098] The avoidance process in the second situation is a process of tilting the insertion part 231 backward in the forklift 10 and then lowering the insertion part 231 in the second direction B. The angle Δθ used in the process of step S201 in the avoidance process in the second situation is, for example, 1°. This fixed value is an angle set after confirming in advance that the distance between the first surface 231a of the insertion part 231 and the first opposing surface IH1 becomes larger than a predetermined value. This fixed value is an angle set after confirming in advance that the distance between the second surface 231b of the insertion part 231 and the second opposing surface IH2 becomes larger than a predetermined value. Therefore, the control device 30 tilts the fork 23 backward by controlling the tilting device in the process of step S203.

[0099] In the avoidance process in the second situation, when the processes of steps S201, S202, S203, S204, and S205 are executed, the insertion part 231 moves away from the second opposing surface IH2 so that the distance between the insertion part 231 and the second opposing surface IH2 becomes larger than a predetermined value.

[0100] By executing steps S201, S202, S203, S204, and S205 in the avoidance process in the second situation, the position SP of the insertion part 231 rises by a specified amount Δh. Therefore, the control device 30 lowers the fork 23 by controlling the lifting device in the process of step S208.

[0101] Even in the avoidance process in the second situation, when the processes of steps S206, S207, S208, S209, and S210 are executed, the position SP of the insertion part 231 returns to the position SP of the insertion part 231 before the avoidance process is executed. That is, the avoidance process is a process of separating the insertion part 231 from the first opposing surface IH1 or the second opposing surface IH2 so that the position SP of the insertion part 231 in the second direction B does not change by controlling the tilting device and the lifting device. Note that the fact that the position SP of the insertion part 231 after the avoidance process is executed returns to the position SP of the insertion part 231 before the avoidance process is executed has been regarded as "the position SP of the insertion part 231 in the second direction B does not change", but it is not limited to this. For example, the fact that the position SP of the insertion part 231 after the avoidance process is executed is slightly deviated from the position SP of the insertion part 231 before the avoidance process is executed may be included in "the position SP of the insertion part 231 in the second direction B does not change". That is, "the position SP of the insertion part 231 in the second direction B does not change" may mean that the position SP of the insertion part 231 after the avoidance process is executed is located within a predetermined range including the position SP of the insertion part 231 before the avoidance process is executed. The predetermined range is set to a range in which the insertion part 231 does not approach the first opposing surface IH1 until the distance between the first surface 231a of the insertion part 231 and the first opposing surface IH1 becomes a predetermined value or less. Also, the predetermined range is set to a range in which the insertion part 231 does not approach the second surface 231b until the distance between the second surface 231b of the insertion part 231 and the second opposing surface IH2 becomes a predetermined value or less.

[0102] When the processes of steps S206, S207, S208, S209, and S210 are executed, the inclination of the insertion part 231 with respect to the first opposing surface IH1 and the second opposing surface IH2 becomes gentler than before the avoidance process is executed. During the avoidance process, the target position and attitude calculation unit 33c continuously outputs a signal of the voltage value PVv required to stop the traveling motor 15 to the command value calculation unit 34. During the avoidance process, the target position and attitude calculation unit 33c continuously outputs a signal of the voltage value θv required by the control valve 41 and the handling motor 43 to stop the operation of the reach cylinder 24 to the command value calculation unit 34. That is, during the avoidance process, the mast 21 does not reach out, and the forklift 10 does not move forward.

[0103] As shown in FIG. 6, after the avoidance process is executed, a NO determination is made in the processes of step S102 and step S105. Thereafter, a YES determination is made in the process of step S106. If the avoidance process is executed in the first situation, a YES determination is made in the process of step S109. If the avoidance process is executed in the second situation, a NO determination is made in the process of step S109.

[0104] The process of step S110 is a process to be executed after the avoidance process in the first situation is executed. The process of step S111 is a process to be executed after the avoidance process in the second situation is executed. In the processes of step S110 and step S111, an adjustment process is executed simultaneously with the insertion process.

[0105] Hereinafter, as an example, the adjustment process executed in the process of step S110 will be described with reference to FIG. 11. As shown in FIG. 11, the adjustment process executed in the process of step S110 is a process of lowering the fork 23 in the second direction B so that the position SP of the insertion portion 231 does not change while inserting the insertion portion 231 into the insertion hole IH by the insertion process. For this reason, when the insertion process and the adjustment process are executed simultaneously in the process of step S110, the insertion portion 231 apparently moves so as to proceed along the extension line of the insertion portion 231 before the adjustment process is executed.

[0106] In the adjustment process executed in the process of step S110, the speed Ps at which the fork 23 is lowered is set so that the position SP of the insertion part 231 does not change when the insertion part 231 is inserted into the insertion hole IH. The speed Ps is determined by how fast the forklift 10 is moved forward with the fork 23 tilted at the tilt angle θ when the process of step S110 is executed. Therefore, the speed Ps is set based on the vehicle speed of the forklift 10, the reach-out speed of the mast 21, and the tilt angle θ of the lift bracket 22 when step S110 is executed. To achieve this, a map or mathematical formula indicating the correlation between the vehicle speed of the forklift 10, the reach-out speed of the mast 21, the tilt angle θ of the lift bracket 22, and the speed Ps is stored in the storage unit 32.

[0107] The target position and attitude calculation unit 33c collates the vehicle speed of the forklift 10 calculated from the movement amount PV, the reach-out speed of the mast 21 calculated from the movement amount Pr, and the tilt angle θ of the lift bracket 22 with a map or mathematical formula. The target position and attitude calculation unit 33c sets the speed Ps from the map or the mathematical formula. The target position and attitude calculation unit 33c calculates a target fork height PL* for realizing the speed Ps and outputs a signal of a voltage value PLv for realizing the target fork height PL* to the command value calculation unit 34. The command value calculation unit 34 calculates a command value for driving the control valve 41 and the handling motor 43 based on the signal of the voltage value PLv for realizing the target fork height PL*. The command value calculation unit 34 operates the lift cylinder 25 by outputting a signal of the voltage value for realizing the command value to the control valve 41 and the handling motor 43. Thereby, the process of step S110 is executed.

[0108] The adjustment process executed in the process of step S111 is a process of raising the fork 23 in the second direction B so that the position SP of the insertion part 231 does not change while inserting the insertion part 231 into the insertion hole IH by the insertion process. The adjustment process executed in the process of step S111 is the same as the adjustment process executed in the process of step S110 except that the fork 23 rises. Therefore, the adjustment process is a process of controlling the lifting device so that the position SP of the insertion part 231 does not change while inserting the insertion part 231 into the insertion hole IH after the avoidance process.

[0109] <Operation of this Embodiment> The operation of this embodiment will be described. Since the avoidance process is executed after the stop process, the insertion part 231 can be separated from the first opposing surface IH1 or the second opposing surface IH2 with the moving device stopped. In the avoidance process, the insertion part 231 is tilted by controlling the tilting device. As the insertion part 231 tilts, the insertion part 231 moves away from the first opposing surface IH1 or the second opposing surface IH2 that the insertion part 231 approaches. As the insertion part 231 tilts, the position of the insertion part 231 with respect to the inlet IHin of the insertion hole IH shifts in the second direction B. However, by controlling the lifting device, the shift can be returned in the second direction B while separating the insertion part 231 from the first opposing surface IH1 or the second opposing surface IH2. That is, the insertion part 231 can be separated from the first opposing surface IH1 or the second opposing surface IH2 so that the position of the insertion part 231 in the second direction B with respect to the inlet IHin of the insertion hole IH does not change from before the insertion part 231 tilts.

[0110] <Effect of this Embodiment> The effect of this embodiment will be described. (1-1) By controlling both the tilting device and the lifting device, the position of the insertion part 231 in the second direction B with respect to the inlet I Hin of the insertion hole IH can be changed from before the insertion part 231 tilts, so that the insertion part 231 can be separated from the first opposing surface IH1 or the second opposing surface IH2. Therefore, it is possible to suppress the insertion part 231 from contacting the first opposing surface IH1 or the second opposing surface IH2 of the insertion hole IH during the avoidance process. Thus, proper insertion of the fork 23 into the insertion hole IH can be realized, and the pallet P can be properly loaded onto the fork 23.

[0111] (1-2) While inserting the insertion part 231 into the insertion hole IH by the insertion process and executing the adjustment process, the insertion of the insertion part 231 into the insertion hole IH can be made possible without changing the relative position of the insertion part 231 with respect to the insertion hole IH as much as possible. For this reason, it becomes difficult for the insertion part 231 to contact the first opposing surface IH1 and the second opposing surface IH2 of the insertion hole IH during the insertion process. Therefore, the frequency of executing the stop process by the detection of the first sensor 51 and the second sensor 52 can be reduced. Thus, since the insertion of the insertion part 231 into the insertion hole IH can be continued as much as possible, the pallet P can be smoothly loaded onto the fork 23.

[0112] (1-3) The insertion of the insertion part 231 into the insertion hole IH can be automatically executed by the insertion process. (1-4) The insertion of the insertion part 231 into the insertion hole IH can be properly executed using only the first sensor 51 and the second sensor 52. For this reason, a forklift 10 capable of realizing the loading of the pallet P can be realized at a lower cost compared to a forklift that requires a sensor for the insertion part 231 in addition to the first sensor 51 and the second sensor 52.

[0113] [Second Embodiment] Hereinafter, a second embodiment in which a forklift is embodied will be described with reference to FIGS. 12 to 15. The main difference from the first embodiment is that new processing is added to the processing flow of the control device. For this reason, detailed description of the same configuration as the first embodiment will be omitted.

[0114] As shown in FIG. 12, the control device 30 executes the processes of step S112, step S113, and step S114 after the process of step S103 in the process flow of the first embodiment.

[0115] When the control device 30 determines YES in the process of step S102 or the process of step S105, the process proceeds to step S103. When the control device 30 executes the stop process in the process of step S103, the process proceeds to step S112.

[0116] The control device 30 executes the position grasping process in the process of step S112. When the control device 30 executes the process of step S112, the process proceeds to step S113. As shown in FIG. 13, the position grasping process is a process of grasping the positions P1 and P2 of the opposing surfaces of the insertion hole IH when the first sensor 51 or the second sensor 52 detects. In the present embodiment, the position P1 of the opposing surface of the insertion hole IH is the position of the first opposing surface IH1 at the first detection by the first sensor 51 or the second sensor 52. The position P1 of the first opposing surface IH1 is represented by coordinates. The position P1 of the first opposing surface IH1 is expressed by the first point P1a which is the position of the first opposing surface IH1 in the first direction A and the second point P1b which is the position of the first opposing surface IH1 in the second direction B. The position P1 of the first opposing surface IH1 is, for example, the position when it is determined YES in the process of step S102 before executing the avoidance process of the first embodiment.

[0117] In this embodiment, the position P2 of the opposing surface of the insertion hole IH is the position of the first opposing surface IH1 at the time of the second detection by the first sensor 51 or the second sensor 52. The position P2 of the first opposing surface IH1 is indicated by coordinates. The position P2 of the first opposing surface IH1 is represented by a third point P2a which is the position of the first opposing surface IH1 in the first direction A and a fourth point P2b which is the position of the first opposing surface IH1 in the second direction B. The position P2 of the first opposing surface IH1 is, for example, the position of the first opposing surface IH1 determined to be YES in the process of step S102 again when the insertion process and the adjustment process are being executed in the process of step S110 in the first embodiment.

[0118] The first point P1a and the third point P2a are examples of a first position which is the position of the first opposing surface IH1 in the first direction A. The second point P1b and the fourth point P2b are examples of a second position which is the position of the first opposing surface IH1 in the second direction B. The first point P1a is an example of a first first position which is the first position at the time of the first detection by the first sensor 51 or the second sensor 52. The second point P1b is an example of a first second position which is the second position at the time of the first detection by the first sensor 51 or the second sensor 52. The third point P2a is an example of a second first position which is the first position at the time of the second detection by the first sensor 51 or the second sensor 52. The fourth point P2b is an example of a second second position which is the second position at the time of the second detection by the first sensor 51 or the second sensor 52.

[0119] The first point P1a and the third point P2a are represented by the sum of the moving amount PV of the forklift 10 and the outreached moving amount Pr of the mast 21. The second point P1b and the fourth point P2b are represented by the height PL of the fork 23. For convenience of explanation, the insertion portion 231 of the fork 23 and the insertion hole IH are shown in FIG. 13, and the illustration of the entire forklift 10 is omitted. Also, when the opposing surface close to the fork 23 is the second opposing surface IH2, the positions P1 and P2 of the opposing surface of the insertion hole IH become the positions of the second opposing surface IH2.

[0120] As shown in FIG. 12, the control device 30 determines whether the detection by the first sensor 51 or the second sensor 52 in the process of step S113 is the second time. The process of step S113 is executed by the approach detection unit 33a. The approach detection unit 33a has a counter that counts the number of times the signals S1 and S2 are input. When the numerical value of the counter becomes "2", the approach detection unit 33a determines that the detection by the first sensor 51 and the second sensor 52 is the second time.

[0121] When the control device 30 determines in the process of step S113 that the detection by the first sensor 51 or the second sensor 52 is not the second time (step S113: NO), the process proceeds to step S104. When the control device 30 determines in the process of step S113 that the detection by the first sensor 51 or the second sensor 52 is the second time (step S113: YES), the process proceeds to step S114. The control device 30 executes target trajectory processing in the process of step S114. Hereinafter, the target trajectory processing will be described.

[0122] As shown in FIG. 14, the control device 30 first executes step S301 in the target trajectory processing. The control device 30 executes target trajectory calculation processing in the process of step S301. The target trajectory calculation processing is a process executed after the stop processing executed at the second detection by the first sensor 51 or the second sensor 52. The target trajectory calculation processing is a process of setting the target trajectory LG. When the control device 30 executes the process of step S301, the process proceeds to step S302.

[0123] As shown in FIG. 13, in the target trajectory calculation processing, the control device 30 sets the target trajectory LG based on the positions P1 and P2 of the first opposing surface IH1 grasped in the position grasping processing. The control device 30 sets the value obtained by dividing the difference between the second point P1b and the fourth point P2b by the difference between the first point P1a and the third point P2a as the inclination of the first opposing surface IH1 and the second opposing surface IH2. The control device 30 sets as the target trajectory LG a straight line obtained by offsetting a virtual straight line having the inclination by a predetermined amount H from the first opposing surface IH1.

[0124] The predetermined amount H is set so that the target trajectory LG does not approach the first opposing surface IH1 until the distance between the target trajectory LG and the first opposing surface IH1 becomes equal to or less than a predetermined value. The predetermined amount H is set so that the target trajectory LG does not approach the second opposing surface IH2 until the distance between the target trajectory LG and the second opposing surface IH2 becomes equal to or less than a predetermined value.

[0125] As shown in FIG. 14, the control device 30 calculates the target tilt angle θ* in the process of step S302. The process of step S302 is executed by the target position and attitude calculation unit 33c. The control device 30 calculates the target tilt angle θ* from the inclination of the target trajectory LG in the process of step S302. When the control device 30 executes the process of step S302, the process proceeds to step S303.

[0126] The control device 30 calculates a command value for operating the tilting device in the process of step S303. The control device 30 calculates command values for the control valve 41 and the handling motor 43 that realize the target tilt angle θ* calculated in the process of step S302 in the process of step S303. When the control device 30 executes the process of step S303, the process proceeds to step S304.

[0127] The control device 30 operates the tilt cylinder 26 by outputting a signal of a voltage value that realizes the command value calculated in the process of step S303 to the control valve 41 and the handling motor 43 in the process of step S304. That is, the control device 30 tilts the fork 23 forward or backward by controlling the tilting device in the process of step S304. The processes of steps S303 and S304 are executed by the command value calculation unit 34. When the control device 30 executes the process of step S304, the process proceeds to step S305.

[0128] The control device 30 determines whether or not the target tilt angle θ※ calculated in the process of step S302 is achieved in the process of step S305. The process of step S305 is executed by the target position and orientation calculation unit 33c. In the process of step S305, the control device 30 determines whether or not the tilt angle θ output from the position and orientation calculation unit 33b based on the signal Sθ of the tilt sensor 56 matches the target tilt angle θ※. If the control device 30 determines in the process of step S305 that the target tilt angle θ※ has not been achieved (step S305: NO), the process of step S304 is continued. That is, the signals output from the command value calculation unit 34 to the control valve 41 and the handling motor 43 in the process of step S304 are continuously output until the target tilt angle θ※ is achieved. If the control device 30 determines in the process of step S305 that the target tilt angle θ※ has been achieved (step S305: YES), the process proceeds to step S306.

[0129] In the process of step S306, the control device 30 stops the tilting device. In the process of step S306, the control device 30 generates a signal of the voltage value θv required by the control valve 41 and the handling motor 43 to stop the operation of the tilt cylinder 26 by the target position and orientation calculation unit 33c. The control device 30 stops the tilting device by outputting the signal of the voltage value θv generated in the process of step S306 to the command value calculation unit 34. When the control device 30 executes step S306, the process proceeds to step S307.

[0130] In the process of step S307, the control device 30 calculates the target fork height PL※. The process of step S307 is executed by the target position and orientation calculation unit 33c. In the process of step S307, the control device 30 calculates the target fork height PL※ from a predetermined amount H of the target trajectory LG. When the control device 30 executes the process of step S307, the process proceeds to the process of step S308.

[0131] The control device 30 calculates a command value for operating the lifting device in the process of step S308. The control device 30 calculates command values for the control valve 41 and the handling motor 43 that realize the target fork height PL※ calculated in the process of step S307 in the process of step S308. When the control device 30 executes the process of step S308, it advances the process to step S309.

[0132] The control device 30 operates the lift cylinder 25 by outputting a signal of a voltage value that realizes the command value calculated in the process of step S308 to the control valve 41 and the handling motor 43 in the process of step S309. That is, the control device 30 raises or lowers the fork 23 by controlling the lifting device in the process of step S309. The processes of steps S308 and S309 are executed by the command value calculation unit 34. When the control device 30 executes the process of step S309, it advances the process to step S310.

[0133] The control device 30 determines whether or not the target fork height PL※ calculated in the process of step S307 has been achieved in the process of step S310. The process of step S310 is executed by the target position and attitude calculation unit 33c. In the process of step S310, the control device 30 determines whether or not the height PL of the fork 23 output from the target position and attitude calculation unit 33c based on the signal SL of the lift sensor 55 matches the target fork height PL※.

[0134] If the control device 30 determines in the process of step S310 that the target fork height PL※ has not been achieved (step S310: NO), it continues the process of step S309. That is, in the process of step S309, the signals output from the command value calculation unit 34 to the control valve 41 and the handling motor 43 are continuously output until the target fork height PL※ is achieved. If the control device 30 determines in the process of step S310 that the target fork height PL※ has been achieved (step S310: YES), it advances the process to step 311.

[0135] The control device 30 stops the lifting device in the process of step S311. The control device 30 generates a signal of the voltage value PLv required by the control valve 41 and the handling motor 43 in order to stop the operation of the lift cylinder 25 in the process of step S311 by the target position and attitude calculation unit 33c. The control device 30 outputs the signal of the voltage value PLv generated in the process of step S311 to the command value calculation unit 34 to stop the lifting device. When the control device 30 executes step S311, the process proceeds to step S312.

[0136] The control device 30 simultaneously executes the insertion process and the maintenance process in the process of step S312. When the control device 30 executes step S312, the process proceeds to step 313. The process of step S313 is the same as the process of step S108. When the control device 30 determines NO in the process of step S313, the process of step S312 is continued. When the control device 30 determines YES in the process of step S313, all the processes for inserting the insertion part 231 into the insertion hole IH are terminated.

[0137] As shown in FIG. 15, when the processes of steps S301 to S311 are executed, the insertion part 231 is arranged on the target trajectory LG. When the processes of steps S301 to S311 are executed, the insertion part 231 extends so as to be parallel to the first opposing surface IH1 and the second opposing surface IH2. The avoidance process of the first embodiment is the first avoidance process executed at the first detection by the first sensor 51 or the second sensor 52. The processes of steps S302 to S311 are processes executed after the target trajectory calculation process, and are the second avoidance process of arranging the insertion part 231 on the target trajectory LG by controlling the lifting device and the lowering device.

[0138] The maintenance process is a process of maintaining the insertion part 231 on the target trajectory LG by controlling the lifting device while inserting the insertion part 231 into the insertion hole IH by the insertion process after the second avoidance process. The maintenance process is basically the same as the adjustment process executed in the process of step S110 and the process of step S111. The maintenance process and the adjustment process are slightly different in terms of setting the speed Ps. The speed Ps set in the maintenance process is set so that any position of the insertion part 231 located on the target trajectory LG does not change with respect to the inlet IHin of the insertion hole IH.

[0139] <Actions of this embodiment> The actions of this embodiment will be described. After the second detection by the first sensor 51 or the second sensor 52 is confirmed, the insertion part 231 is inserted into the insertion hole IH along the target trajectory LG. Therefore, after the second detection by the first sensor 51 or the second sensor 52, the stop process is not executed by the detection of the first sensor 51 or the second sensor 52.

[0140] <Effects of this embodiment> The effects of this embodiment will be described. (2-1) By executing the target trajectory calculation process, the second avoidance process, and the maintenance process by the control device 30, the insertion part 231 is inserted into the insertion hole IH along the target trajectory LG. Since the insertion of the insertion part 231 into the insertion hole IH does not stop due to the stop process, the insertion of the insertion part 231 into the insertion hole IH can be optimized.

[0141] (2-2) The number of times for inserting the insertion part 231 into the insertion hole IH by a specified amount Dth or more can be suppressed to a maximum of 2 times. Therefore, the time for loading the pallet P on the fork 23 can be shortened.

[0142] <Modification example> Note that each of the above embodiments can be modified as follows. Each of the above embodiments and the following modification examples can be implemented in combination with each other within a technically non-conflicting range.

[0143] Although the forklift 10 which is not operated by an operator has been described, the forklift 10 may be operated by an operator. For example, without executing the processes of step S108 and step S313, all the processes for inserting the insertion part 231 into the insertion hole IH may be completed by operating the operation unit 16 by the operator.

[0144] For example, the control device 30 may be changed so that the insertion part 231 is inserted into the insertion hole IH by operating the operation unit 16 by the operator without executing the insertion process. Even in such a case of change, the moving device, the lifting device, and the tilting device are stopped regardless of the operation of the operation unit 16 by the operator when the stop process is executed. And the avoidance process after the stop process is also executed regardless of the operation of the operation unit 16 by the operator.

[0145] ○ It may be added that the position SP in the second direction B of the insertion part 231 with respect to the inlet I Hin of the insertion hole IH does not change when the second stop process is executed under the setting condition of the predetermined amount H.

[0146] ○ The predetermined amount H may be set as follows. For example, the insertion part 231 is actually lifted and lowered in the second direction B by controlling the lifting device until the first sensor 51 and the second sensor 52 react. Half of the moving amount of the insertion part 231 in the second direction B may be set as the predetermined amount H.

[0147] ○ The predetermined amount H may be set as follows. For example, the insertion part 231 is actually lifted and lowered in the second direction B by controlling the lifting device until it contacts the first opposing surface IH1 and the second opposing surface IH2. Half of the moving amount of the insertion part 231 in the second direction B may be set as the predetermined amount H.

[0148] ○ When the size of the insertion hole IH is known in advance, the predetermined amount H may be set to the distance between the center line of the insertion hole IH and the opposing surface of the insertion hole IH. ○ The predetermined amount H may be appropriately changed if the target trajectory LG is not located on the first opposing surface IH1 and the second opposing surface IH2.

[0149] ○ In the avoidance process, after controlling the tilting device, the lifting device was controlled, but it is not limited to this. If the position SP in the second direction B of the insertion part 231 with respect to the inlet IHin of the insertion hole IH can be prevented from changing, the control device 30 may control the tilting device and the lifting device simultaneously. Even if it is changed in this way, in the same manner as in the first embodiment, "the position SP in the second direction B of the insertion part 231 does not change" may mean that the position SP of the insertion part 231 after executing the avoidance process is located within a predetermined range including the position SP of the insertion part 231 before executing the avoidance process.

[0150] ○ The insertion hole IH may be a hole formed in the pallet P. When changed in this way, among the surfaces partitioning the insertion hole IH, the surface facing the first surface 231a of the insertion part 231 is the first opposing surface IH1. Also, among the surfaces partitioning the insertion hole IH, the surface facing the second surface 231b of the insertion part 231 is the second opposing surface IH2.

[0151] ○ In this embodiment, a reach-type forklift is adopted, but as long as it is a forklift equipped with a tilting device, a lifting device, and a moving device, a counter-type forklift may be used. When a counter-type forklift is adopted, the control device 30 calculates the insertion amount Din based on the tilt angle θ of the lift bracket 22 and the moving amount PV of the forklift 10.

Explanation of Signs

[0152] 10... Forklift, 11... Vehicle body, 15... Travel motor, 23... Fork, 30... Control device, 40... Hydraulic mechanism, 41... Control valve, 42... Handling pump, 43... Handling motor, 51... First sensor, 52... Second sensor, 231... Insertion part, A... First direction, B... Second direction, IH... Insertion hole, IHin... Inlet of the insertion hole, IH1... First opposing surface, IH2... Second opposing surface, Din... Insertion amount, Dth... Specified value, H... Predetermined amount, LG... Target trajectory, P... Pallet, P1, P2... Positions, SP... Position of the insertion part with respect to the inlet of the insertion hole.

Claims

1. A vehicle body, a pair of masts, a lift bracket, forks on which a pallet is loaded, a moving device that moves the forks together with the masts in a first direction that includes the forward and rearward directions of the vehicle body, a lifting device that raises or lowers the forks along the mast together with the lift bracket in a second direction that is orthogonal to the first direction and includes the upward and downward directions of the vehicle body, a tilting device that tilts the forks together with the lift bracket with respect to the first direction, When loading the pallet onto the forks, a hole into which the forks are inserted is defined as an insertion hole, a portion of the forks that is inserted into the insertion hole is defined as an insertion portion, and a surface of the insertion hole that faces the insertion portion in the thickness direction of the insertion portion is defined as an opposing surface. A sensor is provided on the insertion portion and detects that the insertion portion has approached the opposing surface until the distance between the insertion portion and the opposing surface becomes a predetermined value or less, a tilt sensor that detects a tilt angle, which is the tilt angle of the lift bracket with respect to the first direction, a lift sensor that detects the height of the forks, and a control device that controls the moving device, the lifting device, and the tilting device, wherein the control device performs a stop process of stopping the moving device, the lifting device, and the tilting device when detected by the sensor, and performs a process to be executed after the stop process, which is an avoidance process of separating the insertion portion from the opposing surface that the insertion portion has approached so that the position of the insertion portion in the second direction with respect to the entrance of the insertion hole does not change by controlling the tilting device and the lifting device, wherein, in the avoidance process, the control device calculates a target tilt angle by adding a predetermined fixed value (Δθ) to the tilt angle detected by the tilt sensor, and performs a tilting process of tilting the insertion portion in the forward or rearward direction of the vehicle body by controlling the tilting device so as to achieve the target tilt angle, calculates a target fork height by adding a specified amount (Δh) to the height of the forks detected by the lift sensor, and performs a lifting process of raising and lowering the insertion portion in the second direction by controlling the lifting device so as to achieve the target fork height, The specified amount (Δh) is the displacement amount between the position of the insertion portion at the entrance of the insertion hole when the stop process is executed and the position of the insertion portion at the entrance of the insertion hole when the insertion portion is rotated by the predetermined fixed value (Δθ). Forklift

2. After the avoidance process, the control device executes an adjustment process of controlling the lifting device while inserting the insertion portion into the insertion hole so that the position of the insertion portion with respect to the entrance of the insertion hole does not change. The forklift according to claim 1.

3. A vehicle body, Forks on which a pallet is loaded, A moving device that moves the forks in a first direction that includes the forward and backward directions of the vehicle body, A lifting device that raises or lowers the forks in a second direction that is orthogonal to the first direction and includes the upward and downward directions of the vehicle body, A tilting device that tilts the forks with respect to the first direction, When the pallet is loaded on the forks, a hole into which the forks are inserted is defined as an insertion hole, a portion of the forks that is inserted into the insertion hole is defined as an insertion portion, and a surface of the surface forming the insertion hole that faces the insertion portion in the thickness direction of the insertion portion is defined as a facing surface. A sensor that is provided in the insertion portion and detects that the insertion portion has approached the facing surface until the distance between the insertion portion and the facing surface becomes a predetermined value or less, A control device that controls the moving device, the lifting device, and the tilting device, The control device is, A stop process of stopping the moving device, the lifting device, and the tilting device when detected by the sensor, A process executed after the stop process, which is a process of controlling the tilting device and the lifting device to separate the insertion portion from the facing surface so that the position of the insertion portion in the second direction with respect to the entrance of the insertion hole does not change when the insertion portion approaches the facing surface, that is, an avoidance process, The avoidance process is a first avoidance process executed at the first detection by the sensor, The control device is, A position grasping process of grasping a first position that is the position of the facing surface in the first direction and a second position that is the position of the facing surface in the second direction when detected by the sensor, The first position at the time of the first detection by the sensor is defined as the first first position, the second position at the time of the first detection by the sensor is defined as the first second position, the first position at the time of the second detection by the sensor is defined as the second first position, and the second position at the time of the second detection by the sensor is defined as the second second position. A value obtained by dividing the difference between the first second position and the second second position by the difference between the first first position and the second first position is defined as the inclination of the opposing surface. When a straight line obtained by offsetting the virtual straight line having the inclination from the opposing surface by a predetermined amount so that the virtual straight line does not approach the opposing surface until the distance between the virtual straight line and the opposing surface becomes equal to or less than a predetermined value is defined as the target trajectory, A process to be executed after the stop process executed at the time of the second detection by the sensor, the target trajectory calculation process for calculating the target trajectory, A process to be executed after the target trajectory calculation process, the second avoidance process for arranging the insertion part on the target trajectory by controlling the lifting device and the tilting device, After the second avoidance process, while inserting the insertion part into the insertion hole, a maintenance process for maintaining the insertion part on the target trajectory by controlling the lifting device is executed Forklift.

4. The control device executes an insertion process for inserting the insertion part into the insertion hole by controlling the moving device The forklift according to any one of claims 1 to 3.

5. When the insertion amount of the insertion part into the insertion hole reaches a specified value, the control device ends all processes for inserting the insertion part into the insertion hole The forklift according to any one of claims 1 to 4.

Images