Work vehicles

Abstract

To control the speed and rate of forward / reverse switching of a work vehicle. [Solution] The work vehicle 1 comprises an electric motor 3 mounted on a vehicle body 2, a traveling device 5 that is driven by the power output from the electric motor 3 to move the vehicle body 2, a first input device that inputs status information indicating the state of at least one of the work vehicle 1 and the surrounding environment, and a controller 11 that determines the required time for a forward / reverse switching operation to switch the vehicle body 2 from forward to reverse or from reverse to forward based on the status information, controls the drive of the electric motor 3 for the required time, and executes the forward / reverse switching operation by the traveling device 5.

Description

Technical Field

[0001] The present invention relates to a technique for switching between forward and reverse travel of a work vehicle that travels by power output from an electric motor.

Background Art

[0002] As a work vehicle that travels using an electric motor as a power source, there is, for example, an electric work vehicle disclosed in Patent Document 1. The electric work vehicle includes an electric motor mounted on the vehicle body, a traveling device that causes the vehicle body to travel, and a control unit that controls the rotation of the electric motor. The wheels included in the traveling device rotate by the power output from the electric motor, thereby causing the vehicle body to travel.

[0003] On the other hand, as a work vehicle that travels using an engine as a power source, there is, for example, a work vehicle disclosed in Patent Document 2. In this work vehicle, according to the vehicle speed when the forward / backward switching lever is operated, the gear stage of the transmission and the operation of the forward / backward clutch are controlled, and the switching between forward and reverse travel of the vehicle body is permitted or restricted.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a work vehicle that travels using an electric motor as a power source, by controlling the rotation direction of the electric motor, it is possible to switch between forward and reverse travel more simply and quickly than a work vehicle that travels using an engine as a power source. However, in order to stabilize the vehicle body, it is desired to control the speed of the forward / backward switching operation. Therefore, an object of the present invention is to control the speed of the forward / backward switching operation of a work vehicle. [Means for solving the problem]

[0006] A work vehicle according to one aspect of the present invention includes an electric motor mounted on the vehicle body, a running device that drives the vehicle body using power output from the electric motor, a first input device that inputs status information indicating the state of at least one of the work vehicle and the surrounding environment, and a controller that determines the required time for a forward / reverse switching operation to switch the vehicle body from forward to reverse or from reverse to forward based on the status information, controls the drive of the electric motor for the required time, and executes the forward / reverse switching operation by the running device. [Effects of the Invention]

[0007] According to the present invention, it is possible to control the speed of the forward and reverse switching operation of a work vehicle. [Brief explanation of the drawing]

[0008] [Figure 1] This is a side view of an example of a work vehicle. [Figure 2] This is a side view of another example of a work vehicle. [Figure 3] This is a block diagram showing an example of the configuration of a system installed in a work vehicle. [Figure 4] This is a schematic diagram of an example of a device related to the driving and steering of a work vehicle. [Figure 5] This diagram shows an example of a field and a travel route set within that field. [Figure 6A] This graph shows an example of the characteristics of switching between forward and reverse movement. [Figure 6B] This graph shows an example of the forward / reverse switching characteristics. [Figure 7A] This graph shows an example of the forward / reverse switching characteristics when a vehicle is stopped. [Figure 7B] This graph shows an example of the forward / reverse switching characteristics when the vehicle is stopped. [Figure 8] This graph shows another example of forward / reverse switching characteristics. [Figure 9A] A graph showing another example of the forward / backward switching characteristics from forward to backward. [Figure 9B] A graph showing another example of the forward / backward switching characteristics from forward to backward. [Figure 9C] A graph showing another example of the forward / backward switching characteristics from backward to forward. [Figure 9D] A graph showing another example of the forward / backward switching characteristics from backward to forward. [Figure 10A] A graph showing another example of the forward / backward switching characteristics from forward to backward. [Figure 10B] A graph showing another example of the forward / backward switching characteristics from backward to forward. [Figure 11] A graph showing another example of the forward / backward switching characteristics when the work vehicle is traveling downhill on a slope. [Figure 12] A list showing an example of the relationship between a plurality of conditions regarding status information and the forward / backward switching characteristics. [Figure 13] A list showing another example of the relationship between a plurality of conditions regarding status information and the forward / backward switching characteristics. [Figure 14] A list showing an example of the setting screen for the forward / backward switching characteristics.

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described with appropriate reference to the drawings.

[0010] FIG. 1 is a side view of an example of the work vehicle 1. In the present embodiment, as an example of the work vehicle 1, a tractor is shown. However, the work vehicle according to the present invention is not limited to a tractor, and may be other agricultural machines, construction machines, or work vehicles, etc. Looking at FIG. 1, the left direction, right direction, front direction, and depth direction are the front, rear, left, and right of the work vehicle 1, respectively. The direction orthogonal to the front-rear direction and the up-down direction of the work vehicle 1 is hereinafter referred to as the vehicle width direction.

[0011] The work vehicle 1 includes a vehicle body 2, an electric motor 3, and a traveling device 5. The vehicle body 2 is equipped with the electric motor 3, a cab 9, etc. The electric motor 3 is a power source for the work vehicle 1 to travel.

[0012] In addition, the work vehicle 1 is equipped with a power source other than the electric motor 3 for traveling. For example, as a power source for devices other than those for traveling of the work vehicle 1, electrical components, and a working device 4 connected to the work vehicle 1, at least one of an electric motor, a battery, an engine, a hydraulic pump, and a hydraulic motor may be mounted on the vehicle body 2. Further, the work vehicle 1 may be an electric work vehicle equipped with an electric motor such as an electric motor as a power source and not equipped with an internal combustion engine such as an engine, or may be a hybrid work vehicle equipped with an electric motor and an internal combustion engine.

[0013] Inside the cab 9, a driver's seat 8 and various operating members are provided. Instead of the cab 9, a protective mechanism such as a canopy and a roll bar may be provided around the driver's seat 8.

[0014] The traveling device 5 is a device that supports the vehicle body 2 so that it can travel from below. The traveling device 5 is driven by the power output from the electric motor 3 to make the vehicle body 2 travel. In the example shown in FIG. 1, the traveling device 5 has a plurality of wheels 5F, 5R. The plurality of wheels 5F, 5R are arranged at intervals in the front-rear direction or the width direction. Specifically, the plurality of wheels 5F, 5R include a pair of left and right front wheels 5F that support the front side of the vehicle body 2 and a pair of left and right rear wheels 5R that support the rear side of the vehicle body 2. Further, each of the plurality of wheels 5F, 5R is a wheel of the wheel-mounted type and has a tire, an annular rim into which the tire is fitted on the outer periphery, and a hub located at the center of the tire and attaching the rim to the axle.

[0015] As another example, a running gear 5 having crawler-type wheels 5C (endless tracks) as shown in Figure 2 may be provided at the rear of the work vehicle 1. The crawler-type wheels 5C are provided in pairs on the left and right at the rear of the vehicle body 2. Each crawler-type wheel 5C has a crawler, a drive wheel that circulates the crawler, and a driven wheel that rotates in conjunction with the circulating drive of the crawler. The crawler is, for example, a rubber crawler made of an elastic material such as rubber. In addition to these, a plurality of idler wheels may be included in each crawler-type wheel 5C.

[0016] The work vehicle 1 is equipped with a coupling device 6. The coupling device 6 is, for example, a three-point linkage coupling device (hitch) installed at the rear of the vehicle body 2, and a work device 4 for performing work can be attached to and detached from it. The coupling device 6 has a lifting mechanism that can raise and lower the work device 4 connected to the coupling device 6, and an actuator such as a hydraulic or electric cylinder that operates the lifting mechanism. The work device 4 is connected to the vehicle body 2 (work vehicle 1) via the coupling device 6 and can be raised and lowered by the coupling device 6. In addition to the three-point linkage coupling device 6, other coupling devices 6 such as a drawbar may be provided on the work vehicle 1.

[0017] Various types of work devices 4 can be connected to the connecting device 6. Examples of work devices 4 include tilling devices (rotary tillers) for tilling fields, rough tilling devices, spraying devices for distributing fertilizer or water, seeding devices for sowing crop seeds or seed potatoes, hilling devices (also called "ridging devices") for hilling, pest control devices for spraying chemicals, or harvesting devices for harvesting crops grown in the field. Furthermore, work devices 4 may be implements or attachments that constitute any of the above devices.

[0018] Furthermore, the work devices 4 include towable work devices that have wheels and are towed by the work vehicle 1 when connected to the coupling device 6, and direct-mounted work devices that do not have wheels and are supported by the work vehicle 1 while suspended above the ground when connected to the coupling device 6. In addition, the work devices 4 include heavy-duty work devices with a weight above a predetermined threshold and lightweight work devices with a weight below a predetermined threshold. Furthermore, the work devices 4 include work devices that have a drive unit driven by power transmitted from the work vehicle 1 via the PTO shaft 7 and work devices that do not have such a drive unit. In addition, the work devices 4 include work devices equipped with an electronic control unit including a CPU and work devices that do not have such an electronic control unit. Besides these, various other types of work devices 4 can be connected to the vehicle body 2 (work vehicle 1) via the coupling device 6.

[0019] Figure 3 is a block diagram showing an example of the configuration of a system installed in work vehicle 1. More specifically, the system shown in Figure 3 is a forward / reverse switching system for switching between forward and reverse movement of work vehicle 1. Figure 4 is a schematic diagram of an example of the devices related to the driving and steering of work vehicle 1.

[0020] As shown in Figure 3, in addition to the aforementioned electric motor 3 for travel, travel device 5, and coupling device 6, the work vehicle 1 is equipped with a controller 11, high-voltage battery 12, PDU (Power Distribution Unit) 13, inverter 14, power transmission device 15, steering device 16, braking device 17, low-voltage battery 18, forward / reverse lever 10, accelerator (so-called accelerator, acceleration device) 19, user interface (indicated as "UI" in Figure 3) 20, internal sensor unit 21, external sensor unit 22, positioning device 23, and communication device 24.

[0021] The controller 11 consists of a VCU (Vehicle Control Unit) or computer having a processor such as a CPU and memory 11a. The controller 11 controls the operation of each part of the work vehicle 1. Memory 11a is a storage device that stores various types of information and includes volatile memory and non-volatile memory. Various types of information and data for the controller 11 to control the operation of each part are stored in memory 11a in a read-write manner. In addition to memory 11a, the work vehicle 1 may also be equipped with other storage devices, such as memory drives including an SSD (Solid State Drive).

[0022] The controller 11 includes a motor control unit 11b, an automatic control unit 11c, an actual vehicle speed detection unit 11d, a target vehicle speed determination unit 11e, and a characteristic determination unit 11f. The motor control unit 11b, automatic control unit 11c, actual vehicle speed detection unit 11d, target vehicle speed determination unit 11e, and characteristic determination unit 11f are composed of software programs or hardware.

[0023] The high-voltage battery 12 is a secondary battery that stores high-voltage power and is the power source for the operation of the work vehicle 1. The PDU 13 has a switching circuit that switches the destination of the power output. The inverter 14 is a drive device that has a drive circuit that drives the electric motor 3. The inverter 14 supplies power output from the high-voltage battery 12 via the PDU 13 to the electric motor 3, thereby rotating the electric motor 3.

[0024] The power transmission device 15 is a device (differential) that transmits power output from the electric motor 3 to the running gear 5. Specifically, as shown in Figure 4, for example, the power transmission device 15 transmits the rotational driving force transmitted from the electric motor 3 to the propeller shaft 29 to the pair of rear wheels 5R(5C), which are the drive wheels, via the drive shaft 28 to the multiple wheels 5F, 5R(5C) of the running gear 5. As a result, the pair of rear wheels 5R(5C) are driven, and the pair of front wheels 5F, which are the driven wheels, are also driven. The power transmission device 15 may also include a transmission that continuously changes the vehicle speed of the work vehicle 1.

[0025] As another example, among the multiple wheels 5F, 5R(5C) of the running gear 5, a pair of front wheels 5F may be drive wheels and a pair of rear wheels 5R(5C) may be driven wheels. In this case, the power transmission device 15 should be configured to transmit power output from the electric motor 3 to the pair of front wheels 5F. Alternatively, the power transmission device 15 may be configured to be switchable between a two-wheel drive state in which power is transmitted to either the pair of front wheels 5F or the pair of rear wheels 5R(5C), and a four-wheel drive state in which power is transmitted to all wheels 5F, 5R(5C).

[0026] The electric motor 3 consists of a motor-generator. The electric motor 3 outputs power to the running gear 5 via the power transmission device 15, and also generates electricity by performing regenerative operation using the rotational driving force input from the running gear 5 via the power transmission device 15, such as when the work vehicle 1 is decelerating. The electricity generated by the electric motor 3 is input to the high-voltage battery 12 via the inverter 14 and PDU 13. In other words, the high-voltage battery 12 is charged with the electricity generated by the electric motor 3.

[0027] The motor control unit 11b (Figure 3) of the controller 11 detects the discharge state, charge state, and amount of stored energy of the high-voltage battery 12. The motor control unit 11b also controls the operation of the PDU 13 to discharge power (current) from the high-voltage battery 12 and supply that power to the inverter 14, or to supply power generated by the electric motor 3 from the inverter 14 to the high-voltage battery 12 and store (charge) that power in the high-voltage battery 12.

[0028] Furthermore, the motor control unit 11b controls the operation of the inverter 14 to supply current to the electric motor 3, thereby driving the electric motor 3 to rotate. The motor control unit 11b also controls the rotational speed and direction of the electric motor 3 by changing the magnitude and direction of the current supplied to the electric motor 3 by the inverter 14. As the rotational speed of the electric motor 3 changes, the rotational speed of the wheels 5F and 5R (5C) of the running gear 5 also changes, and the vehicle speed (traveling speed) of the vehicle body 2 and the work vehicle 1 changes. Also, when the electric motor 3 rotates in the forward direction, the wheels 5F and 5R (5C) rotate in the forward direction, causing the running gear 5 and the vehicle body 2 to move forward, and the work vehicle 1 also moves forward. Also, when the electric motor 3 rotates in the reverse direction, the wheels 5F 5R(5C) rotates in the reverse direction, causing the running gear 5 and the vehicle body 2 to move backward, and the work vehicle 1 also moves backward.

[0029] The controller 11, via the motor control unit 11b, controls the electric motor 3 and the running gear 5 via the inverter 14 to move the vehicle body 2 (work vehicle 1), change the vehicle speed of the vehicle body 2 (work vehicle 1), and change the direction of travel. More specifically, the controller 11, via the motor control unit 11b, controls (changes) the rotation speed of the electric motor 3 via the inverter 14, thereby also controlling (changing) the rotation speed of the wheels 5F and 5R (5C) of the running gear 5, thereby increasing (accelerating) or decreasing (decelerating) the vehicle speed of the vehicle body 2 and work vehicle 1. In addition, the controller 11, via the motor control unit 11b, controls the rotation direction of the electric motor 3 via the inverter 14, thereby also controlling the rotation direction of the wheels 5F and 5R (5C), and performs a forward / reverse switching operation to switch the vehicle body 2 and work vehicle 1 from a forward state to a reverse state or from a reverse state to a forward state.

[0030] In this embodiment, a single electric motor 3 is shown as the drive source for the movement of the work vehicle 1, but the work vehicle 1 may be equipped with multiple electric motors as the drive source. For example, the work vehicle 1 may be equipped with a front electric motor that rotates a pair of left and right front wheels 5F, and a rear electric motor that rotates a pair of left and right rear wheels 5R (or wheels 5C). Alternatively, the work vehicle 1 may be equipped with a left electric motor that rotates at least one of the drive wheels among the front wheels 5F and rear wheels 5R (or wheels 5C) on the left side of the vehicle body 2, and a right electric motor that rotates at least one of the drive wheels among the front wheels 5F and rear wheels 5R (or wheels 5C) on the right side of the vehicle body 2. Alternatively, the work vehicle 1 may be equipped with four electric motors that rotate the front wheel 5F on the left front side of the vehicle body 2, the front wheel 5F on the right front side, the rear wheel 5R (or wheel 5C) on the left rear side, and the rear wheel 5R (or wheel 5C) on the right rear side, respectively.

[0031] The steering device 16 is a device that changes the steering direction and steering angle (rudder angle) of the work vehicle 1 (vehicle body 2). As shown in Figure 4, the steering device 16 has a steering wheel 16a, a steering shaft 16b, a steering actuator 16c, and a pair of left and right knuckle arms 16d.

[0032] The steering handle 16a is located inside the cabin 9 (Figure 1) and is operated by a driver seated in the driver's seat 8. The steering shaft 16b rotatably supports the steering handle 16a. The steering actuator 16c is composed of, for example, an electric cylinder and extends and retracts in accordance with the rotation angle and direction of the steering shaft 16b. The knuckle arm 16d is connected to the steering actuator 16c and changes the direction of the front wheels 5F by moving in accordance with the operation (extension and retraction) of the steering actuator 16c. The steering device 16 changes the steering direction and steering angle (steering angle) of the vehicle body 2 by changing the direction of the front wheels 5F with the above configuration, thereby steering the work vehicle 1.

[0033] Furthermore, the steering system 16 allows the steering actuator 16c to be activated not only by the driver's manual operation of the steering wheel 16a, but also by control signals from the controller 11, thereby changing the direction of the front wheels 5F. As another example, the steering actuator 16c may be a hydraulic actuator such as a hydraulic cylinder, or an electric actuator such as a servo cylinder or servo motor.

[0034] The braking device 17 (Figure 3) is a device that brakes the running gear 5. The braking device 17 has a braking device such as a pedal or lever, a braking actuator, and a disc-type brake mechanism located inside the cabin 9. In the braking device 17, the braking device is operated manually, or the braking actuator is operated in response to a control signal from the controller 11. When the tuner is activated, the braking mechanism engages, braking the pair of rear wheels 5R (or wheels 5C) on the left and right sides.

[0035] The coupling device 6 has the aforementioned lifting actuator and lifting switch. In response to an operation signal from the lifting switch or a control signal from the controller 11, the lifting actuator is activated, causing the work device 4 connected to the coupling device 6 to move up and down. The low-voltage battery 18 can output power at a lower voltage than the high-voltage battery 12 to the controller 11 and the electrical equipment installed in the work vehicle 1.

[0036] The forward / reverse selector lever 10 is located inside the cabin 9. The forward / reverse selector lever 10 is operated by the driver (operator) to input an instruction to execute a forward / reverse operation of the vehicle body 2 (work vehicle 1). In other words, the forward / reverse selector lever 10 is an input device (input interface) for inputting an instruction to execute a forward / reverse operation. When the controller 11 receives an instruction to execute a forward / reverse operation via the forward / reverse selector lever 10, the motor control unit 11b and the inverter 14 control the rotation speed and rotation direction of the electric motor 3 to execute a forward / reverse operation (switching the vehicle body 2 from forward to reverse or from reverse to forward) according to the instruction.

[0037] As another example, the work vehicle 1 may be equipped with operating devices other than levers, such as push buttons, tumbler switches, and pedals, as input devices for inputting instructions to execute forward / reverse switching operations. Alternatively, operating units such as keys generated by a software program, such as keys displayed on a display included in the user interface 20, may constitute an input device for inputting instructions to execute forward / reverse switching operations.

[0038] The accelerator 19, user interface 20, internal sensor unit 21, external sensor unit 22, positioning device 23, and communication device 24 are input devices (input interfaces) that input status information (including signals and data) indicating the state (status) of at least one of the work vehicle 1 and the surrounding environment of the work vehicle 1. The controller 11 stores the status information input by these devices in the memory 11a. The status information also includes status information indicating the state of the work device 4 connected to the work vehicle 1.

[0039] Furthermore, at least one of the following status information may be pre-stored in memory 11a: vehicle information relating to work vehicle 1, device information relating to work device 4 that can be attached to work vehicle 1 (vehicle body 2), and map information including the topography of the area where work vehicle 1 travels. In addition, the map information may include field information relating to the field where work is performed by the work device 4 while work vehicle 1 is traveling, and area information relating to areas other than fields. The field information may also include information indicating the outline, topography, location, location of the work area, and location of the headland of the field. The area information may include information indicating the map, topography, and location of the area.

[0040] The accelerator 19 is operated by the driver (operator) to change the speed of the vehicle body 2 (work vehicle 1). The accelerator 19 also has an operating device such as a lever, pedal, or switch located inside the cabin 9, and an electrical circuit that outputs an operating signal corresponding to the amount of operation of the operating device. The target vehicle speed determination unit 11e of the controller 11 detects the amount of operation of the accelerator 19 based on the operating signal from the accelerator 19 and determines the target vehicle speed based on that amount of operation. The controller 11 then drives the running gear 5 by controlling the rotational speed of the electric motor 3 with the inverter 14 so that the speed of the vehicle body 2 reaches the target vehicle speed.

[0041] The user interface 20 is a touch panel, display, located inside the cabin 9. The system includes a display and a speaker. The operator can input status information of the work vehicle 1 and the work device 4 connected to the work vehicle 1 via the user interface 20. The operator can also input status information of the surrounding environment of the work vehicle 1 via the user interface 20, including field information regarding the field in which the work vehicle 1 is traveling and area information regarding areas other than the field. The user interface 20 also outputs various types of information to the operator by displaying them on the display or outputting them as sound from the speaker. The user interface 20 is both an output device (output interface) and a display device that displays information.

[0042] The internal sensor unit 21 is a unit that includes multiple sensors for inputting status information indicating the state of each part of the work vehicle 1. The internal sensor unit 21 includes an occupant sensor 21a, a steering angle sensor 21b, a rotation speed sensor 21c, an IMU (Inertial Measurement Unit) 21d, and a load sensor 21e. At least one of the occupant sensor 21a, steering angle sensor 21b, rotation speed sensor 21c, IMU 21d, and load sensor 21e may be included in the internal sensor unit 21. In addition, other sensors may be included in the internal sensor unit 21.

[0043] The occupant sensor 21a consists of, for example, a seat switch installed on the seating area of ​​the driver's seat 8, a camera that images the inside of the cabin 9, or a biosensor installed inside the cabin 9. The occupant sensor 21a detects the presence or absence of an occupant in the work vehicle 1. The controller 11 may determine whether or not an occupant is on board the work vehicle 1 based on the detection result of the occupant sensor 21a.

[0044] The steering angle sensor 21b detects the steering angle of the vehicle body 2. More specifically, the steering angle sensor 21b is composed of an angle sensor that detects the rotation angle of the steering shaft of the steering device 16. The controller 11 then detects the rotation angle of the steering shaft detected by the angle sensor as the steering angle of the vehicle body 2. The controller 11 may also determine whether the vehicle body 2 is moving straight or turning based on the steering angle detected by the steering angle sensor 21b. For example, the controller 11 determines that the vehicle body 2 is moving straight if the steering angle of the vehicle body 2 is less than a predetermined value, and determines that the vehicle body 2 is turning if the steering angle is greater than or equal to the predetermined value.

[0045] The rotation speed sensor 21c detects the rotation speed of the electric motor 3. The IMU 21d detects the three-dimensional inertial motion of the vehicle body 2 (translational motion and rotational motion in the orthogonal three-axis directions). The actual vehicle speed detection unit 11d of the controller 11 calculates (detects) the vehicle speed (actual vehicle speed) of the vehicle body 2 based on the rotation speed of the electric motor 3 detected by, for example, the rotation speed sensor 21c. Alternatively, the actual vehicle speed detection unit 11d calculates the acceleration of the vehicle body 2 based on the detection result of the IMU 21d, and calculates (detects) the vehicle speed of the vehicle body 2 from that acceleration.

[0046] The controller 11 detects (calculates) the direction of travel of the vehicle body 2 based on the detection results of the IMU 21d. The controller 11 also detects (calculates) the attitude of the vehicle body 2, including its pitch angle, roll angle, and yaw angle (direction, orientation), based on the detection results of the IMU 21d. Furthermore, the controller 11 considers the yaw angle calculated from the detection results of the IMU 21d as the steering angle of the vehicle body 2. The IMU 21d is also a sensor that detects the steering angle of the vehicle body 2.

[0047] The controller 11 may consider the yaw angle calculated from the detection results of the IMU 21d as the steering angle of the vehicle body 2 and determine whether the vehicle body 2 is moving in a straight line or turning. For example, the controller 11 may determine that the vehicle body 2 is moving in a straight line if the yaw angle of the vehicle body 2 is less than a predetermined value, and that the vehicle body 2 is turning if the yaw angle is greater than or equal to the predetermined value.

[0048] Furthermore, the controller 11 may determine whether the vehicle body 2 (work vehicle 1) is traveling on flat ground or on an incline based on the pitch angle of the vehicle body 2 calculated from the detection results of the IMU 21d. For example, if the pitch angle of the vehicle body 2 is less than a predetermined value, the controller 11 determines that the vehicle body 2 is traveling on flat ground that does not have an incline greater than or equal to a predetermined value, and if the pitch angle of the vehicle body 2 is greater than or equal to a predetermined value, the controller 11 determines that the vehicle body 2 is traveling on an incline that has an incline greater than or equal to a predetermined value.

[0049] The load sensor 21e detects the load acting on the coupling device 6. Based on the load detected by the load sensor 21e, the controller 11 determines whether or not the work device 4 is connected to the coupling device 6, and the weight and type of the work device 4 connected to the coupling device 6.

[0050] Specifically, the controller 11 determines that the work device 4 is not connected if the load detected by the load sensor 21e is less than a predetermined value, and determines that the work device 4 is connected if the load is equal to or greater than the predetermined value. Furthermore, the controller 11 determines that a lightweight work device 4 is connected if the load detected by the load sensor 21e is equal to or greater than the predetermined value but less than a predetermined threshold greater than the predetermined value, and determines that a heavy-duty work device 4 is connected if the load is equal to or greater than the threshold.

[0051] The external sensor unit 22 is a unit that includes multiple sensors of various types that input status information (including signals and data) indicating the state of the surrounding environment of the work vehicle 1. The external sensor unit 22 includes a laser sensor 22a, such as LIDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging), and a camera 22c. The laser sensor 22a and camera 22c are installed at appropriate locations such as the front, rear, left and right sides, top, and bottom of the work vehicle 1 to detect the state of the surrounding environment of the work vehicle 1 and the work device 4. At least one of the laser sensor 22a and camera 22c may be included in the external sensor unit 22. In addition, other sensors (such as ultrasonic sensors) may be included in the external sensor unit 22.

[0052] The laser sensor 22a detects objects within a predetermined distance from the work vehicle 1 and measures the distance to the object by Time of Flight (TOF). The camera 22c captures images of the surroundings of the work vehicle 1, including the front, rear, left, and right sides. The controller 11 detects objects present around the work vehicle 1 (within the imaging range of the camera 22c) based on at least one of the detection results from the laser sensor 22a and the images captured by the camera 22c. These objects include not only predetermined obstacles that hinder the movement of the work vehicle 1, but also objects other than obstacles, such as the ground (road surface) on which the work vehicle 1 travels, and the work equipment 4 connected to the coupling device 6. The laser sensor 22a and the camera 22c are also sensors that detect the work equipment 4 connected to the coupling device 6.

[0053] The controller 11 may determine whether or not the work device 4 is connected to the coupling device 6 based on at least one of the detection results of the laser sensor 22a and the image captured by the camera 22c. Alternatively, the controller 11 may determine the type of work device 4 connected to the coupling device 6 based on the image captured by the camera 22c that captures the rear of the work vehicle 1.

[0054] Specifically, the controller 11 extracts an image of the work device 4 from the image of the rear of the vehicle body 2 captured by the camera 22c, and from the image of the work device 4, determines the type of work device 4, including its model name (tillage device, spraying device, ..., harvesting device, etc.) which indicates the purpose (operable work) of the work device 4. The controller 11 also determines whether the work device 4 is a directly mounted work device supported by the vehicle body 2, or a towed work device pulled by the vehicle body 2.

[0055] Furthermore, the controller 11 may determine whether the work device 4 is a small work device with height and width less than predetermined values, or a large work device with height and width greater than or equal to predetermined values. Also, if the controller 11 determines that the work device 4 connected to the coupling device 6 is a small work device, it may determine (estimate) that the work device 4 is a lightweight work device, or if the controller 11 determines that the work device 4 is a large work device, it may determine (estimate) that the work device 4 is a heavy-duty work device.

[0056] Furthermore, the controller 11 may determine at least one of the terrain and area of ​​the location where the work vehicle 1 is located, based on at least one of the detection results of the laser sensor 22a and the images captured by the camera 22c. For example, the controller 11 may determine the slope of the ground on which the vehicle body 2 is located, based on at least one of the detection results of the laser sensor 22a and the images captured by the camera 22c. The laser sensor 22a and the camera 22c are also sensors that detect the slope of the ground.

[0057] More specifically, the controller 11 determines whether the ground on which the vehicle body 2 is located is sloped based on at least one of the detection results from the laser sensor 22a and the images captured by the camera 22c. If the controller 11 determines that the ground is sloped, it determines that the work vehicle 1 is traveling on a sloped area, and if it determines that the ground on which the vehicle body 2 is located is not sloped, it determines that the work vehicle 1 is traveling on flat ground.

[0058] Furthermore, the controller 11 may calculate the slope of the ground on which the vehicle body 2 is located based on at least one of the detection results of the laser sensor 22a and the captured image of the camera 22c. The controller 11 may then determine that the work vehicle 1 is traveling on flat ground if the slope of the ground is less than a predetermined value, and that the work vehicle 1 is traveling on sloped ground if the slope is equal to or greater than the predetermined value.

[0059] Furthermore, the controller 11 may determine the direction of the ground slope (uphill or downhill) based on at least one of the detection results of the laser sensor 22a and the images captured by the camera 22c. Based on the direction of the ground slope, the controller 11 may then determine whether the vehicle body 2 (work vehicle 1) is traveling uphill or downhill. Specifically, the controller 11 determines that the vehicle body 2 is traveling uphill if the ground slopes upward in the direction of travel of the vehicle body 2, and determines that the vehicle body 2 is traveling downhill if the ground slopes downward in the direction of travel of the vehicle body 2.

[0060] Furthermore, the controller 11 may detect the location of an obstacle based on at least one of the detection results of the laser sensor 22a and the image captured by the camera 22c, and determine the size of the area in which the work vehicle 1 can travel without coming into contact with the obstacle (such as the area of ​​the drivable range).

[0061] The positioning device 23 is mounted on the vehicle body 2 and determines its own position (positioning information including latitude and longitude) using the Global Navigation Satellite System (GNSS). Specifically, the positioning device 23 has a GNSS receiver that receives signals transmitted from positioning satellites (position of the positioning satellite, transmission time, correction information, etc.), and detects its own position based on the signals received by the GNSS receiver. The controller 11 may consider the position determined by the positioning device 23 as the position of the vehicle body 2 (work vehicle 1), and may determine whether the vehicle body 2 is moving in a straight line or turning based on the time-series data of that position. The actual vehicle speed detection unit 11d may detect (calculate) the vehicle speed of the vehicle body 2 based on the time-series data of the position determined by the positioning device 23.

[0062] The communication device 24 is a communication interface and input / output interface for communicating with at least one of the work device 4, server 31, terminal device 32, and remote device 33. The communication device 24 includes a wired communication port 24a, a short-range communication device 24b, and a wide-area communication device 24c. At least one of the wired communication port 24a, the short-range communication device 24b, and the wide-area communication device 24c may be included in the communication device 24.

[0063] The wired communication port 24a is a port for wired communication with an electronic control device such as a CPU or other electronic device mounted on the work device 4. When the electronic control device of the work device 4 is connected to the wired communication port 24a via an electrical cable, the controller 11 becomes able to communicate with the electronic control device. Also, when other electronic devices (such as a computer or storage medium) are connected to the wired communication port 24a via an electrical cable, the controller 11 becomes able to communicate with those electronic devices.

[0064] The short-range communication device 24b is a wireless communication device that transmits and receives wireless signals compliant with short-range wireless communication standards such as Bluetooth® Low Energy. When the work device 4 connected to the coupling device 6 is equipped with a wireless communication device compliant with short-range wireless communication standards and an electronic control device, the electronic control device and the controller 11 communicate wirelessly using the wireless communication device and the short-range communication device 24b to transmit and receive information.

[0065] The information transmitted from the electronic control unit of the work device 4 (including other electronic devices) to the controller 11 via a wired connection through the wired communication port 24a or wirelessly via the short-range communication device 24b includes identification information of the work device 4. The memory 11a of the controller 11 stores identification information of multiple work devices 4 that can be connected to the coupling device 6 and are usable on the work vehicle 1, along with device information indicating at least one of their type and specifications. The controller 11 reads the device information corresponding to the identification information of the work device 4 received from the electronic control unit of the work device 4 from the memory 11a, and determines the type of work device 4 connected to the coupling device 6 based on the read device information.

[0066] Alternatively, the information transmitted to the controller 11 by wired or wireless connection from the electronic control unit of the work device 4 may include device information indicating the type of work device 4 (including its specifications). In this case, the controller 11 determines the type of work device 4 connected to the coupling device 6 based on the device information received from the electronic control unit of the work device 4.

[0067] The wide-area communication device 24c is a communication device that communicates with at least one of the server 31, terminal device 32, and remote device 33 via a wide-area network such as a mobile phone communication network and the internet. The server 31 is a computer located in a management center or cloud system. The server 31 has a database which stores vehicle information of the work vehicle 1, device information of the work equipment 4 that can be connected to the work vehicle 1, and map information including the topography of the fields and other areas where the work vehicle 1 is located and travels.

[0068] The terminal device 32 is a portable or stationary computer. The terminal device 32 is equipped with a user interface that allows input and output of vehicle information of the work vehicle 1, equipment information of the work device 4, and map information of the location where the work vehicle 1 is located and traveling. The remote control device 33 is a device for an operator located at a remote location to remotely control the work vehicle 1, and is operated by the operator.

[0069] The controller 11 communicates with at least one of the server 31 and the terminal device 32 via the wide-area communication device 24c to receive vehicle information of the work vehicle 1, device information of the work equipment 4, and map information of the location where the work vehicle 1 is located and traveling. The controller 11 also communicates with the remote device 33 via the wide-area communication device 24c to receive remote control signals transmitted from the remote device 33 in response to operator operations.

[0070] At least one of the vehicle information received by the wide-area communication device 24c of the communication device 24, the vehicle information input via the user interface 20, or the vehicle information pre-stored in the memory 11a indicates whether the work vehicle 1 is a manned work vehicle or an unmanned work vehicle. Therefore, the controller 11 may determine whether or not there is an occupant on the work vehicle 1 based on the vehicle information. Specifically, if at least one of the above vehicle information indicates that the work vehicle 1 is a manned work vehicle, the controller 11 determines that there is an occupant on the work vehicle 1, and if it indicates that the work vehicle 1 is an unmanned work vehicle, the controller 11 determines that there is no occupant on the work vehicle 1.

[0071] Furthermore, the controller 11 may determine that the work device 4 is connected to the vehicle body 2 when it receives device information for the work device 4 via the wired communication port 24a or short-range communication device 24b of the communication device 24, and may determine that the work device 4 is not connected to the vehicle body 2 if it does not receive device information. Alternatively, the controller 11 may determine that the work device 4 is connected to the vehicle body 2 when device information for the work device 4 connected to the vehicle body 2 is input via the user interface 20.

[0072] Furthermore, the controller 11 may determine the type of work device 4 connected to the vehicle body 2 based on device information received via the wired communication port 24a or the short-range communication device 24b, device information input via the user interface 20, or device information pre-stored in the memory 11a.

[0073] Furthermore, the controller 11 may read the slope of the ground where the position is located from the map information received by the wide-area communication device 24c of the communication device 24 and the position determined by the positioning device 23 (the position of the vehicle body 2), and determine whether the vehicle body 2 is traveling on flat ground or on an incline based on the slope. Specifically, when the electric motor 3 is running, the controller 11 compares the map information with the position determined by the positioning device 23 and detects the slope of the ground where the position is located. Based on the comparison result, the controller 11 determines that the vehicle body 2 is traveling on flat ground if the slope of the ground where the position determined by the positioning device 23 is located is less than a predetermined value, and determines that the vehicle body 2 is traveling on an incline if the slope is equal to or greater than the predetermined value. Furthermore, the controller 11 may determine whether the vehicle body 2 is traveling uphill or downhill based on the inclination of the ground where the position determined by the positioning device 23 is located and the direction of travel of the vehicle body 2.

[0074] The work vehicle 1 is configured to be able to move and perform tasks through manual operation, in which a driver (occupant) seated in the driver's seat 8 (Figure 1) operates the steering wheel 16a, accelerator 19, and braking controls. In addition, the work vehicle 1 is configured to be able to move and perform tasks through automatic operation, in which the automatic control unit 11c of the controller 11 operates the inverter 14, electric motor 3, steering device 16, braking device 17, and coupling device 6, without manual operation.

[0075] Furthermore, the automatic driving of the work vehicle 1 includes at least one of automatic driving, autonomous driving, and remote driving. Automatic driving of the work vehicle 1 is a mode in which the automatic control unit 11c controls the inverter 14, electric motor 3, steering device 16, and braking device 17, etc., based on a preset driving path and the position (position of the vehicle body 2) determined by the positioning device 23, thereby causing the work vehicle 1 to drive automatically along the driving path.

[0076] For example, when the automatic operation of the work vehicle 1 is performed in a field, the automatic control unit 11c, based on the travel path and the position determined by the positioning device 23, automatically drives the work vehicle 1 along the travel path while performing work on the work area of ​​the field with the work device 4 connected to the coupling device 6. The information indicating the travel route may be stored in memory 11a beforehand, or it may be transmitted from server 31 or terminal device 32 and received by wide-area communication device 24c.

[0077] Autonomous driving of the work vehicle 1 is a mode in which the automatic control unit 11c determines a driving path toward a preset target point and controls the inverter 14, electric motor 3, steering device 16, and braking device 17, etc., based on the driving path and the position determined by the positioning device 23, thereby automatically driving the work vehicle 1 along the driving path. Information indicating the target point may be input by the driver via the user interface 20, or it may be input by the operator via the terminal device 32 and then received from the terminal device 32 via the wide-area communication device 24c.

[0078] Remote operation of the work vehicle 1 is a mode in which the automatic control unit 11c controls the inverter 14, electric motor 3, steering device 16, and braking device 17, etc., based on remote operation signals from the remote device 33 received by the wide-area communication device 24c, to automatically drive the work vehicle 1 and perform work using the work device 4. The remote device 33 is equipped with one or more operating devices corresponding to the steering wheel 16a, forward / reverse selector lever 10, accelerator 19, braking device, and lift / lower switch on the work vehicle 1, and remote operation signals corresponding to the operation of the operating devices are transmitted from the remote device 33 to the work vehicle 1.

[0079] The remote control signal from the remote device 33 includes an instruction to execute a forward / reverse switching operation, which is transmitted when the operating tool corresponding to the forward / reverse switching lever 10 is operated. This instruction is received by the wide-area communication device 24c of the communication device 24. The communication device 24 is an input device (input interface) to which the instruction to execute a forward / reverse switching operation from the remote device 33 is input.

[0080] As another example, the work vehicle 1 may be a work vehicle that does not operate manually but operates automatically. In this case, the driver's seat 8 and protective mechanisms such as the cabin 9 that protects the driver seated in the driver's seat 8 may be omitted from the work vehicle 1. Also, as yet another example, the work vehicle 1 may be a work vehicle that does not operate automatically but operates manually.

[0081] The characteristic determination unit 11f of the controller 11 determines (defines) the forward / reverse switching characteristics, which are characteristics related to the speed from the start to the end of the forward / reverse switching operation of the work vehicle 1 (vehicle body 2). Specifically, the characteristic determination unit 11f determines at least one of the following as the forward / reverse switching characteristics: the time required for the forward / reverse switching operation and the rate of change of vehicle speed, which is the amount of change of vehicle speed per unit time during the forward / reverse switching operation. Based on the forward / reverse switching characteristics determined by the characteristic determination unit 11f, the controller 11 uses the motor control unit 11b to operate the inverter 14, controlling the rotational speed and rotational drive direction of the electric motor 3, and the travel device 5 executes the forward / reverse switching operation of the work vehicle 1.

[0082] Furthermore, when the controller 11 receives an instruction to perform a forward / reverse switching operation by, for example, an operator such as a driver operating the forward / reverse switching lever 10, the characteristic determination unit 11f determines the forward / reverse switching characteristics, and the motor control unit 11b executes the forward / reverse switching operation based on those forward / reverse switching characteristics. Alternatively, when the controller 11 receives (inputs) an instruction to perform a forward / reverse switching operation from the remote device 33 via the communication device 24, the characteristic determination unit 11f determines the forward / reverse switching characteristics, and the motor control unit 11b executes the forward / reverse switching operation based on those forward / reverse switching characteristics.

[0083] Alternatively, the controller 11 determines the timing for executing a forward / reverse switching operation on the work vehicle 1 based on the status of the work vehicle 1 and the surrounding environment, which is indicated by status information input by at least one of the user interface 20, internal sensor unit 21, external sensor unit 22, positioning device 23, and communication device 24. Then, the controller 11 At the time of the determination, the characteristic determination unit 11f determines the forward / reverse switching characteristics, and the motor control unit 11b executes the forward / reverse switching operation based on the forward / reverse switching characteristics.

[0084] Specifically, when the controller 11 is automatically driving the vehicle 2 based on a driving path Z1 set in field H1, as shown in Figure 5 (during automatic or autonomous driving), it determines the timing to execute a forward / reverse switching operation based on the field information regarding field H1 indicated in the status information, the position determined by the positioning device 23 (position of the vehicle 2), and the driving path Z1.

[0085] More specifically, the work vehicle 1 needs to make a U-turn as shown by the dashed line in Figure 5 in order to change direction at the headland E1 located between the work area C1 and the edge H2 of the field H1. Therefore, the controller 11 may determine the timing to execute the forward / reverse switching operation when the position of the vehicle body 2 reaches the end point of any of the straight sections Z1a (the tip of the thick solid arrow) if, for example, the spacing D1 between the multiple straight sections Z1a of the travel path Z1 set in the work area C1 located in the center of the field H1 is less than a first predetermined value. Alternatively, even if the spacing D1 between the straight sections Z1a is greater than or equal to the first predetermined value, the controller 11 may determine the timing to execute the forward / reverse switching operation when the position of the vehicle body 2 reaches the end point of any of the straight sections Z1a if the headland width D2, which is the distance from the work area C1 to the edge H2 of the field H1, is less than a second predetermined value.

[0086] As another example, the controller 11 may determine that it is time to execute a forward / reverse switching operation when the distance to an obstacle detected by at least one of the laser sensor 22a and camera 22c falls below a third predetermined value while the work vehicle 1 is in motion. Alternatively, when the controller 11 receives an instruction to execute a forward / reverse switching operation from a control device installed on the work vehicle 1 other than the forward / reverse switching lever 10 and the remote device 33, or from an external device such as the server 31 and terminal device 32, the characteristic determination unit 11f may determine the forward / reverse switching characteristics and execute the forward / reverse switching operation based on those characteristics.

[0087] Furthermore, the controller 11 may determine the forward / reverse switching characteristics while the work vehicle 1 is in motion, or it may determine the forward / reverse switching characteristics while the work vehicle 1 is stopped (when the vehicle speed is zero). Also, the controller 11 may determine the forward / reverse switching characteristics at the timing when the forward / reverse switching operation is started in the work vehicle 1, or before or after that timing. That is, the controller 11 may determine the forward / reverse switching characteristics by the characteristic determination unit 11f when the forward / reverse switching operation is not being performed in the work vehicle 1, or it may determine the forward switching characteristics by the characteristic determination unit 11f while the forward / reverse switching operation is being performed.

[0088] Furthermore, the controller 11 may perform a forward / reverse switching operation by the motor control unit 11b based on the forward / reverse switching characteristics while the work vehicle 1 (vehicle body 2) is in motion, or it may perform a forward / reverse switching operation by the motor control unit 11b based on the forward / reverse switching characteristics while the work vehicle 1 is stopped.

[0089] Figures 6A and 6B are graphs showing examples of forward / reverse switching characteristics. Specifically, Figure 6A is a graph showing an example of forward / reverse switching characteristics when switching vehicle 2 from forward to reverse. (Figures 7A, 9A, 9B, and 10A, described later, are similar.) Figure 6B is a graph showing an example of forward / reverse switching characteristics when switching vehicle 2 from reverse to forward. (Figures 7B, 9C, 9D, and 10B, described later, are similar.) In the graphs of Figures 6A and 6B, the horizontal axis represents time, and the vertical axis represents the vehicle speed of vehicle 2 (work vehicle 1). When vehicle 2 is moving forward, the vehicle speed is a positive (+) value greater than zero (0), and when vehicle 2 is moving backward, the vehicle speed is a negative (-) value less than zero (0). (The graphs showing examples of forward / reverse switching characteristics in Figures 7A to 11, described later, are similar.)

[0090] Before (immediately before) the forward / reverse switching operation begins, the controller 11 first detects the current vehicle speed +Vr1 and -Vr2 as initial vehicle speeds using the actual vehicle speed detection unit 11d, and then determines the target vehicle speeds -Vt1 and +Vt2 using the target vehicle speed determination unit 11e. The controller 11 determines the target vehicle speeds -Vt1 and +Vt2 using the target vehicle speed determination unit 11e based on the input of the accelerator 19. As an alternative, the target vehicle speeds -Vt1 and +Vt2 may be fixed values ​​set in advance, or they may be values ​​obtained by inverting the signs of the (+) and (-) of the initial vehicle speeds +Vr1 and -Vr2 (i.e., -Vt1=-Vr1, +Vt2=+Vr2).

[0091] The controller 11 then uses the characteristic determination unit 11f to determine the forward / reverse switching characteristics, for example, the time required T1 and T2 to reach the target vehicle speed -Vt1 and +Vt2 from the initial vehicle speed +Vr1 and -Vr2. When the controller 11 switches the vehicle body 2 from forward to reverse, as shown in Figure 6A, the characteristic determination unit 11f determines the first time required T1 to reach the target reverse vehicle speed -Vt1 from the initial vehicle speed (actual vehicle speed when moving forward) +Vr1. When the controller 11 switches the vehicle body 2 from reverse to forward, as shown in Figure 6B, the characteristic determination unit 11f determines the second time required T2 to reach the target forward vehicle speed +Vt2 from the initial vehicle speed (actual vehicle speed when moving backward) -Vr2.

[0092] Alternatively, the controller 11 may determine, using the characteristic determination unit 11f, as a forward / reverse switching characteristic, the following: a first deceleration time T1d until the initial vehicle speed +Vr1 of the vehicle 2 in forward motion is reduced to 0 (zero), and a first acceleration time T1i from the time the vehicle speed is reduced to 0 until the vehicle 2 is moved in reverse at a target reverse vehicle speed -Vt1, as shown in Figure 6A. The first required time T1 is the sum of the first deceleration time T1d and the first acceleration time T1i.

[0093] Alternatively, the controller 11 may determine, using the characteristic determination unit 11f, as a forward / reverse switching characteristic, the second deceleration time T2d until the initial vehicle speed -Vr2 of the vehicle body 2 while it is in reverse becomes 0 (zero), and the second acceleration time T2i from when the vehicle speed becomes 0 until the vehicle body 2 moves forward at the target forward vehicle speed +Vt2, as shown in Figure 6B. The second required time T2 is the sum of the second deceleration time T2d and the second acceleration time T2i.

[0094] Furthermore, the controller 11 may use the characteristic determination unit 11f to set the first required time T1 and the second required time T2 determined as described above as base times, multiply the first required time T1 and the second required time T2 by coefficients to change at least one of them, thereby determining the first required time T1 and the second required time T2 (see Figures 10A and 10B described later). The controller 11 may also use the characteristic determination unit 11f to multiply the first deceleration time T1d, the first acceleration time T1i, the second deceleration time T2d, and the second acceleration time T2i by coefficients to change at least one of them, thereby determining the first required time T1d, T1i, T2d, and T2i. The controller 11 may also determine the coefficients according to the status information.

[0095] Furthermore, the controller 11 may determine (calculate) the vehicle speed change rates R1 and R2, which are the amount of change in vehicle speed per unit time, based on the required times T1 and T2, etc., as forward / reverse switching characteristics using the characteristic determination unit 11f. In this case, when the controller 11 switches the vehicle body 2 from forward to reverse, the characteristic determination unit 11f determines the first vehicle speed change rate R1, which is the amount of change in vehicle speed per unit time from the initial vehicle speed +Vr1 to the reverse target vehicle speed -Vt1, based on the first required time T1, etc. (first deceleration time T1d, first acceleration time T1i), as shown in Figure 6A. The first vehicle speed change rate R1 is the slope of the characteristic line L1, which is a linear straight line representing the change in vehicle speed, as shown in Figure 6A.

[0096] Furthermore, when the controller 11 switches the vehicle body 2 from reverse to forward, it performs the following actions based on the second required time T2 (second deceleration time T2d, second acceleration time T2i) as shown in Figure 6B. Next, the characteristic determination unit 11f determines the second vehicle speed change rate R2, which is the amount of change per unit time in vehicle speed from the initial vehicle speed -Vr2 to the target forward vehicle speed +Vt2. The second vehicle speed change rate R2 is the slope of the characteristic line L2, which is a linear straight line representing the change in vehicle speed, as shown in Figure 6B.

[0097] Furthermore, the controller 11 may determine (calculate) the following as forward / reverse switching characteristics using the characteristic determination unit 11f: a first deceleration rate R1d, which is the amount of deceleration per unit time of the vehicle speed until the initial vehicle speed + Vr1 of the vehicle 2 in forward motion is reduced to 0; and a first acceleration rate R1i, which is the amount of acceleration per unit time of the vehicle speed from when the vehicle speed is reduced to 0 until the vehicle 2 is reversed at the target reverse vehicle speed - Vt1. In the example shown in Figure 6A, since the characteristic line L1 is a linear function, the first deceleration rate R1d, the first acceleration rate R1i, and the first vehicle speed change rate R1 are the same value.

[0098] Furthermore, the controller 11 may determine (calculate) the following as forward / reverse switching characteristics using the characteristic determination unit 11f: a second deceleration rate R2d, which is the amount of deceleration per unit time of the vehicle speed until the initial vehicle speed -Vr2 of the vehicle 2 in reverse is reduced to 0; and a second acceleration rate R2i, which is the amount of acceleration per unit time of the vehicle speed from when the vehicle speed is reduced to 0 until the vehicle 2 moves forward at a target forward vehicle speed +Vt2. Note that in the example shown in Figure 6B, since the characteristic line L2 is a linear function, the second deceleration rate R2d, the second acceleration rate R2i, and the second vehicle speed change rate R2 are the same value.

[0099] In the example above, the controller 11 determined the required times T1 and T2 as forward / reverse switching characteristics, and then calculated the vehicle speed change rates R1 and R2. Alternatively, the controller 11 may determine the vehicle speed change rates R1 and R2, or it may calculate the required times T1 and T2 from the vehicle speed change rates R1 and R2.

[0100] In this case, the controller 11 uses the characteristic determination unit 11f to determine the forward / reverse switching characteristics, for example, the vehicle speed change rates R1 and R2 from the initial vehicle speeds +Vr1 and -Vr2 to the target vehicle speeds -Vt1 and +Vt2. When the controller 11 switches the vehicle body 2 from forward to reverse, as shown in Figure 6A, the characteristic determination unit 11f determines the first vehicle speed change rate R1 from the initial vehicle speed +Vr1 to the target vehicle speed -Vt1. When the controller 11 switches the vehicle body 2 from reverse to forward, as shown in Figure 6B, the characteristic determination unit 11f determines the second vehicle speed change rate R2 from the initial vehicle speed -Vr2 to the target vehicle speed +Vt2.

[0101] Furthermore, the controller 11 may determine a first reduction ratio R1d and a first acceleration ratio R1i as forward / reverse switching characteristics using the characteristic determination unit 11f, as shown in Figure 6A, in order to switch the vehicle body 2 from forward to reverse. Alternatively, the controller 11 may determine a second reduction ratio R2d and a second acceleration ratio R2i as forward / reverse switching characteristics using the characteristic determination unit 11f, in order to switch the vehicle body 2 from reverse to forward.

[0102] Furthermore, the controller 11 may determine (calculate) the required times T1 and T2 as forward and reverse switching characteristics based on the vehicle speed change rates R1 and R2 using the characteristic determination unit 11f. In this case, when the controller 11 switches the vehicle body 2 from forward to reverse, the characteristic determination unit 11f determines (calculates) the first required time T1, etc. (first deceleration rate R1d, first acceleration rate R1i) based on the first vehicle speed change rate R1, etc. (first deceleration rate R1d, first acceleration rate R1i), as shown in Figure 6A.

[0103] Furthermore, when the controller 11 switches the vehicle body 2 from reverse to forward, it performs the following actions based on the second vehicle speed change rate R2 (second deceleration rate R2d, second acceleration rate R2i), as shown in Figure 6B. The second required time T2 (second deceleration time T2d, second acceleration time T2i) is determined (calculated) by the characteristic determination unit 11f.

[0104] Furthermore, the controller 11 may also change at least one of the first and second vehicle speed change rates R1 and R2 determined as described above by multiplying them by coefficients using the characteristic determination unit 11f, thereby finalizing the vehicle speed change rates R1 and R2 (see Figures 10A and 10B described later). In addition, the controller 11 may also change at least one of the deceleration rates R1d and R2d and acceleration rates R1i and R2i determined as described above by multiplying them by coefficients using the characteristic determination unit 11f, thereby finalizing the deceleration rates R1d and R2d and acceleration rates R1i and R2i.

[0105] Once the controller 11 determines the forward / reverse switching characteristics as described above, it executes the forward / reverse switching operation over a period of time T1 and T2, for example. That is, the controller 11 controls the rotation speed and direction of the electric motor 3 using the inverter 14 over a period of time T1 and T2, and the travel device 5 executes the forward / reverse switching operation.

[0106] Specifically, when switching the vehicle body 2 from forward to reverse, the controller 11, over a first required time T1, changes the rotational speed of the electric motor 3 using the inverter 14 from a rotational speed corresponding to the initial vehicle speed + Vr1 to a rotational speed corresponding to the reverse target vehicle speed - Vt1, and also reverses the rotation direction of the electric motor 3, thereby changing the rotational speed and reversing the rotation direction of the wheels 5F and 5R (5C) of the running gear 5, and moving the vehicle body 2 in reverse at the reverse target vehicle speed - Vt1.

[0107] Alternatively, the controller 11 may use the inverter 14 to reduce the rotational speed of the electric motor 3 over a first deceleration time T1d from a rotational speed corresponding to the initial vehicle speed + Vr1 to a rotational speed corresponding to a vehicle speed of 0 (zero) (for example, rotational speed = 0 (zero)). Then, the controller 11 may use the inverter 14 to increase the rotational speed of the electric motor 3 over a first acceleration time T1i from a rotational speed corresponding to a vehicle speed of 0 (zero) to a rotational speed corresponding to the reverse target vehicle speed - Vt1. In this way as well, over a first required time T1, the rotational direction of the electric motor 3 is reversed, the rotational speeds of the wheels 5F and 5R (5C) of the running gear 5 are also changed and their rotational directions are reversed, and the vehicle body 2 moves in reverse at the reverse target vehicle speed - Vt1.

[0108] Alternatively, the controller 11 may change the rotational speed of the electric motor 3 using the inverter 14 from a rotational speed corresponding to the initial vehicle speed + Vr1 to a rotational speed corresponding to the reverse target vehicle speed - Vt1 using a first vehicle speed change rate R1. Alternatively, the controller 11 may reduce the rotational speed of the electric motor 3 using the inverter 14 from a rotational speed corresponding to the initial vehicle speed + Vr1 to a rotational speed corresponding to vehicle speed 0 (zero) using a first reduction rate R1d, and then increase the rotational speed of the electric motor 3 from a rotational speed corresponding to vehicle speed 0 (zero) to a rotational speed corresponding to the reverse target vehicle speed - Vt1 using a first acceleration rate R1i. In either case, the rotational direction of the electric motor 3 is reversed over a first required time T1, the rotational speeds of the wheels 5F and 5R (5C) of the running gear 5 are also changed and their rotational directions are reversed, and the vehicle body 2 moves backward at the reverse target vehicle speed - Vt1.

[0109] Furthermore, when switching the vehicle body 2 from reverse to forward, the controller 11, over a second required time T2, changes the rotational speed of the electric motor 3 using the inverter 14 from a rotational speed corresponding to the initial vehicle speed - Vr2 to a rotational speed corresponding to the target forward vehicle speed + Vt2, and also reverses the rotational direction of the electric motor 3, thereby changing the rotational speed and reversing the rotational direction of the wheels 5F and 5R (5C) of the running gear 5, and moving the vehicle body 2 forward at the target forward vehicle speed + Vt2.

[0110] Alternatively, the controller 11 may use the inverter 14 to reduce the rotational speed of the electric motor 3 by applying a second deceleration time T2d, from a rotational speed corresponding to the initial vehicle speed - Vr2 to a rotational speed corresponding to vehicle speed 0 (zero). Then, the controller 11 may use the inverter 14 to increase the rotational speed of the electric motor 3 by applying a second acceleration time T2i, from a rotational speed corresponding to vehicle speed 0 (zero) to a rotational speed corresponding to the forward target vehicle speed + Vt2. In this way as well, the rotational direction of the electric motor 3 is reversed over the second required time T2, the rotational speeds of the wheels 5F and 5R (5C) of the running gear 5 are also changed and their rotational directions are reversed, and the vehicle body 2 moves forward at the forward target vehicle speed + Vt2.

[0111] Alternatively, the controller 11 may change the rotational speed of the electric motor 3 using the inverter 14 from a rotational speed corresponding to the initial vehicle speed - Vr2 to a rotational speed corresponding to the target forward vehicle speed + Vt2 using the second vehicle speed change rate R2. Alternatively, the controller 11 may reduce the rotational speed of the electric motor 3 using the inverter 14 from a rotational speed corresponding to the initial vehicle speed + Vr2 to a rotational speed corresponding to vehicle speed 0 (zero) using the second reduction rate R2d, and then increase the rotational speed of the electric motor 3 from a rotational speed corresponding to vehicle speed 0 (zero) to a rotational speed corresponding to the target forward vehicle speed + Vt2 using the second acceleration rate R2i. In either case, the rotational direction of the electric motor 3 is reversed over a second required time T2, the rotational speeds of the wheels 5F and 5R (5C) of the running gear 5 are also changed and their rotational directions are reversed, and the vehicle body 2 moves forward at the target forward vehicle speed + Vt1.

[0112] Furthermore, if the accelerator 19 is operated by the operator during the forward / reverse switching operation and the amount of operation of the accelerator 19 changes, the controller 11 completes the forward / reverse switching operation based on the forward / reverse switching characteristics determined before the start of the forward / reverse switching operation, and then changes the rotational speed of the electric motor 3 by the motor control unit 11b according to the changed amount of operation of the accelerator 19, thereby driving the vehicle body 2.

[0113] Alternatively, the controller 11 may update the target vehicle speeds -Vt1 and +Vt2 in accordance with the changed amount of operation of the accelerator 19 while the forward / reverse switching operation is being performed. The controller 11 may also update the forward / reverse switching characteristics (at least one of the required time T1 and T2, vehicle speed change rate R1 and R2, deceleration time T1d and T2d, acceleration time T1i and T2i, deceleration rate R1d and R2d, and acceleration rate R1i and R2i) in accordance with the updated target vehicle speeds -Vt1 and +Vt2. Furthermore, the controller 11 may execute the forward / reverse switching operation by controlling the rotation speed and rotation direction of the electric motor 3 with the motor control unit 11b based on the updated forward / reverse switching characteristics.

[0114] In the examples shown in Figures 6A and 6B, the controller 11 determined the forward / reverse switching characteristics for executing the forward / reverse switching operation when the initial vehicle speed +Vr1 and -Vr2 before the start of the forward / reverse switching operation are not 0 (zero), that is, while the vehicle body 2 is moving. However, the controller 11 may also determine the forward / reverse switching characteristics for executing the forward / reverse switching operation when the initial vehicle speed +Vr1 and -Vr2 are 0, that is, while the vehicle body 2 is stopped, as shown in Figures 7A and 7B, for example.

[0115] Specifically, when switching the vehicle body 2 from forward to reverse while the vehicle body 2 is stopped, the controller 11, using the characteristic determination unit 11f, determines at least one of the following as the forward / reverse switching characteristics, as shown in Figure 7A: the first required time T1 from the initial vehicle speed + Vr1 = 0 (zero) to the reverse target vehicle speed - Vt1, the first acceleration time T1i (T1i = T1), the first vehicle speed change rate R1, and the first acceleration rate R1i (R1i = R1).

[0116] Furthermore, when switching the vehicle body 2 from reverse to forward while the vehicle body 2 is stopped, the controller 11, using the characteristic determination unit 11f, determines at least one of the following as the forward / reverse switching characteristics, as shown in Figure 7B: the second required time T2 from the initial vehicle speed -Vr2=0 (zero) to the target forward vehicle speed +Vt2, the second acceleration time T2i (T2i=T2), the second vehicle speed change rate R2, and the second acceleration rate R2i (R2i=R2).

[0117] The controller 11 controls the initial vehicle speed + Vr1 when switching the vehicle 2 from forward to reverse. Even if the countervalue and the absolute value of the initial vehicle speed -Vr2 when switching vehicle 2 from reverse to forward are the same (|+Vr1|=|-Vr2|), and the absolute value of the target vehicle speed -Vt1 when switching vehicle 2 from forward to reverse is the same as the absolute value of the target vehicle speed +Vt2 when switching vehicle 2 from reverse to forward (|-Vt1|=|+Vt2|), the characteristic determination unit 11f may set the first required time T1 and the second required time T2 to different times.

[0118] For example, as shown in Figure 8, the controller 11 may, using the characteristic determination unit 11f, determine that the first required time T1 when switching the vehicle body 2 from forward to reverse is longer than the second required time T2 when switching the vehicle body 2 from reverse to forward. Alternatively, the controller 11 may, using the characteristic determination unit 11f, determine that the first vehicle speed change rate R1 when switching the vehicle body 2 from forward to reverse is smaller than the second vehicle speed change rate R2 when switching the vehicle body 2 from reverse to forward. In these cases, the forward / reverse switching operation when switching the vehicle body 2 from forward to reverse is performed more slowly than the forward / reverse switching operation when switching the vehicle body 2 from reverse to forward.

[0119] Furthermore, the controller 11 may use the characteristic determination unit 11f to make the first deceleration rate R1d and the first acceleration rate R1i different when switching the vehicle body 2 from forward to reverse, and the first deceleration time T1d and the first acceleration time T1i different as well. Specifically, the controller 11 may use the characteristic determination unit 11f to change at least one of the first deceleration rate R1d, the first acceleration rate R1i, the first deceleration time T1d, and the first acceleration time T1i, which have been determined once, by multiplying them by a coefficient, and then finalize these values.

[0120] Furthermore, the controller 11 may, for example, set the first deceleration rate R1d to be smaller than the first acceleration rate R1i, and the first deceleration time T1d to be longer than the first acceleration time T1i, as shown in Figure 9A. This allows the vehicle speed to be gradually decelerated from the initial forward vehicle speed + Vr1 to 0 (zero), preventing the vehicle body 2 from becoming unstable due to a large inertial force, and also allows the vehicle speed to be quickly accelerated from 0 (zero) to the reverse target vehicle speed - Vt1, so that the forward and reverse switching operation is performed (completed) stably and quickly.

[0121] Furthermore, the controller 11 may, for example, set the first deceleration rate R1d to be greater than the first acceleration rate R1i, and the first deceleration time T1d to be shorter than the first acceleration time T1i, as shown in Figure 9B. This allows the vehicle speed to be quickly decelerated from the initial forward speed + Vr1 to 0 (zero), and then slowly accelerated from 0 (zero) to the reverse target vehicle speed - Vt1, so that the forward and reverse switching operation is executed (completed) quickly and stably.

[0122] Furthermore, the controller 11 may use the characteristic determination unit 11f to make the second deceleration rate R2d and the second acceleration rate R2i different when switching the vehicle body 2 from reverse to forward, and the second deceleration time T2d and the second acceleration time T2i different as well. Specifically, the controller 11 may use the characteristic determination unit 11f to change at least one of the second deceleration rate R2d, the second acceleration rate R2i, the second deceleration time T2d, and the second acceleration time T2i by multiplying them by a coefficient, and then determine these values.

[0123] Furthermore, the controller 11 may, for example as shown in Figure 9C, make the second deceleration rate R2d smaller than the second acceleration rate R2i and the second deceleration time T2d longer than the second acceleration time T2i. This allows the vehicle speed to be gradually reduced from the initial vehicle speed -Vr2 during reverse to 0 (zero), preventing the vehicle body 2 from becoming unstable due to a large inertial force, and then the vehicle speed to be quickly increased from 0 (zero) to the forward target vehicle speed +Vt2, so that the forward / reverse switching operation is performed (completed) stably and quickly.

[0124] Furthermore, the controller 11 may, for example, make the second deceleration rate R2d greater than the second acceleration rate R2i and make the second deceleration time T2d shorter than the second acceleration time T2i, as shown in Figure 9D. Good. This allows the vehicle speed to quickly decelerate from the initial reverse speed -Vr2 to 0 (zero), then slowly increase from 0 (zero) to the target forward speed +Vt2, stably moving the vehicle 2 forward, and ensuring that the forward / reverse switching operation is executed quickly and stably.

[0125] As described above, the status information input by the user interface 20, internal sensor unit 21, external sensor unit 22, positioning device 23, and communication device 24 includes information indicating at least one of the following: whether or not there is an occupant in the work vehicle 1, the driving status of the work vehicle 1, the coupling status of the work device 4 to the vehicle body 2, the type of work device 4 coupled to the vehicle body 2, and the location where the work vehicle 1 is located. The controller 11 may determine the forward / reverse switching characteristics using the characteristic determination unit 11f based on any of the status information.

[0126] Furthermore, the controller 11 may determine the forward / reverse switching characteristics by the characteristic determination unit 11f based on whether predetermined conditions relating to the status information of the work vehicle 1, the work device 4, or the surrounding environment are met or not. In addition, the controller 11 may determine coefficients based on whether the predetermined conditions are met or not, and use these coefficients to determine (confirm) the forward / reverse switching characteristics (required time T1, T2, deceleration time T1d, T2d, acceleration time T1i, T2i, vehicle speed change rate R1, R2, deceleration rate R1d, R2d, acceleration rate R1i, R2i) by the characteristic determination unit 11f.

[0127] For example, the controller 11 determines whether or not there is an occupant in the work vehicle 1 based on the detection result of the occupant sensor 21a, which is status information of the work vehicle 1, under predetermined conditions. Alternatively, the controller 11 determines whether or not there is an occupant in the work vehicle 1 based on at least one of the following: vehicle information received by the wide-area communication device 24c of the communication device 24, vehicle information input via the user interface 20, or vehicle information pre-stored in the memory 11a. The controller 11 then determines the forward / reverse switching characteristics using the characteristic determination unit 11f so that the forward / reverse switching operation is performed more quickly when there is no occupant in the work vehicle 1 than when there is an occupant.

[0128] More specifically, as shown in Figure 10A, in the forward / reverse switching operation that switches the vehicle body 2 from forward to reverse, if there is an occupant on the work vehicle 1, the controller 11 determines the first vehicle speed change rate R1b and the first required time T1b as shown on the characteristic line L1b using the characteristic determination unit 11f. If there is no occupant on the work vehicle 1, the controller 11 determines the first vehicle speed change rate R1a and the first required time T1a as shown on the characteristic line L1a using the characteristic determination unit 11f. The absolute value of the first vehicle speed change rate R1a is greater than the absolute value of the first vehicle speed change rate R1b, and the first required time T1a is shorter than the first required time T1b.

[0129] Furthermore, as shown in Figure 10B, for example, in the forward / reverse switching operation that switches the vehicle body 2 from reverse to forward, if there is an occupant on the work vehicle 1, the controller 11 determines the second vehicle speed change rate R2b and the second required time T2b using the characteristic determination unit 11f, as shown on the characteristic line L2b. If there is no occupant on the work vehicle 1, the controller 11 determines the second vehicle speed change rate R2a and the second required time T2a using the characteristic determination unit 11f, as shown on the characteristic line L2a. The absolute value of the second vehicle speed change rate R2a is greater than the absolute value of the second vehicle speed change rate R2b, and the second required time T2a is shorter than the second required time T2b.

[0130] The characteristic line L1a in Figure 10A is the forward / reverse switching characteristic calculated by multiplying the slope of the reference characteristic line determined by the controller 11 based on the initial vehicle speed +Vr1 and the reverse target vehicle speed -Vt1 by a coefficient of "1". In other words, characteristic line L1a is the same as the reference characteristic line. The characteristic line L1b is the forward / reverse switching characteristic calculated by the controller 11 by multiplying the reference characteristic line by a coefficient greater than "1" (for example, "1.2"). The characteristic line L2a in Figure 10B is the forward / reverse switching characteristic calculated by multiplying the slope of the reference characteristic line determined by the controller 11 based on the initial vehicle speed -Vr2 and the forward target vehicle speed +Vt2 by a coefficient of "1". In other words, characteristic line L2a is the same as the reference characteristic line. The characteristic line L2b is the forward / reverse switching characteristic calculated by the controller 11 by multiplying the reference characteristic line by a coefficient greater than "1" (for example, "1.2").

[0131] Furthermore, the controller 11 determines whether the vehicle body 2 is moving straight or turning, based on at least one of the status information of the work vehicle 1: the steering angle detected by the steering angle sensor 21b, the yaw angle (steering angle) calculated from the detection result of the IMU 21d, and the time-series data of the position detected by the positioning device 23, as a predetermined condition.The controller 11 then determines the forward / reverse switching characteristics using the characteristic determination unit 11f so that the forward / reverse switching operation is performed more quickly when the vehicle body 2 is moving straight than when it is turning.

[0132] More specifically, in the forward / reverse switching operation as shown in Figure 10A, when the vehicle body 2 is turning, the controller 11 determines the first vehicle speed change rate R1b and the first required time T1b as shown on characteristic line L1b, and when the vehicle body 2 is moving straight, it determines the first vehicle speed change rate R1a and the first required time T1a as shown on characteristic line L1a. Furthermore, in the forward / reverse switching operation as shown in Figure 10B, when the vehicle body 2 is turning, the controller 11 determines the second vehicle speed change rate R2b and the second required time T2b as shown on characteristic line L2b, and when the vehicle body 2 is moving straight, it determines the second vehicle speed change rate R2a and the second required time T2a as shown on characteristic line L2a.

[0133] Furthermore, the controller 11 determines whether the work device 4 is connected to the vehicle body 2 based on at least one of the status information of the work device 4, which includes the load detected by the load sensor 21e, the detection result of the rear of the vehicle body 2 by the laser sensor 22a, and the image of the rear of the vehicle body 2 captured by the camera 22c, under predetermined conditions. Alternatively, the controller 11 determines whether the work device 4 is connected to the vehicle body 2 based on whether or not it has received device information of the work device 4 via either the wired communication port 24a or the short-range communication device 24b of the communication device 24.

[0134] Alternatively, the controller 11 determines whether the work device 4 connected to the vehicle body 2 is connected to the vehicle body 2 based on whether or not the device information of the work device 4 connected to the vehicle body 2 has been input via the user interface 20. The controller 11 then determines the forward / reverse switching characteristics using the characteristic determination unit 11f so that the forward / reverse switching operation is performed more quickly when the work device 4 is not connected to the vehicle body 2 than when it is connected.

[0135] More specifically, as shown in Figure 10A, when the controller 11 switches the vehicle body 2 from forward to reverse, if the work device 4 is connected to the vehicle body 2, it determines the first vehicle speed change rate R1b and the first required time T1b as shown on characteristic line L1b, and if the work device 4 is not connected to the vehicle body 2, it determines the first vehicle speed change rate R1a and the first required time T1a as shown on characteristic line L1a. Furthermore, as shown in Figure 10B, when the controller 11 switches the vehicle body 2 from reverse to forward, if the work device 4 is connected to the vehicle body 2, it determines the second vehicle speed change rate R2b and the second required time T2b as shown on characteristic line L2b, and if the work device 4 is not connected to the vehicle body 2, it determines the second vehicle speed change rate R2a and the second required time T2a as shown on characteristic line L2a.

[0136] Furthermore, the controller 11 determines the type of work device 4 connected to the vehicle body 2 based on at least one of the detection results of the load sensor 21e, the detection results of the laser sensor 22a, and the image captured by the camera 22c, and determines whether the type is a predetermined type under predetermined conditions. Alternatively, the controller 11 receives device information via the wired communication port 24a or the short-range communication device 24b, and device information input via the user interface 20. Alternatively, based on device information pre-stored in memory 11a, the controller 11 determines the type of work device 4 connected to the vehicle body 2 and whether or not that type is a predetermined type. The controller 11 then uses the characteristic determination unit 11f to determine the forward / reverse switching characteristics so that when the type of work device 4 connected to the vehicle body 2 is a predetermined type, the forward / reverse switching operation is performed more quickly than when it is not a predetermined type.

[0137] More specifically, the controller 11 determines whether the type of work device 4 connected to the vehicle body 2 is, for example, a directly mounted work device or a towed work device. Then, as shown in Figure 10A, in the forward / reverse switching operation that switches the vehicle body 2 from forward to reverse, if the work device 4 is a towed work device, the controller 11 determines the first vehicle speed change rate R1b and the first required time T1b as shown in characteristic line L1b, and if the work device 4 is a directly mounted work device, the controller 11 determines the first vehicle speed change rate R1a and the first required time T1a as shown in characteristic line L1a.

[0138] Furthermore, as shown in Figure 10B, in the forward / reverse switching operation that switches the vehicle body 2 from reverse to forward, the controller 11 determines the second vehicle speed change rate R2b and the second required time T2b as shown in characteristic line L2b when the work device 4 is a towing type work device, and determines the second vehicle speed change rate R2a and the second required time T2a as shown in characteristic line L2a when the work device 4 is a direct-mount type work device.

[0139] Specifically, the absolute values ​​of the first vehicle speed change rate R1a and the second vehicle speed change rate R2a, determined when the working device 4 is a directly mounted working device, are made larger than the absolute values ​​of the first vehicle speed change rate R1b and the second vehicle speed change rate R2b, determined when the working device 4 is a towed working device. In addition, the first required time T1a and the second required time T2a, determined when the working device 4 is a directly mounted working device, are made shorter than the first required time T1b and the second required time T2b, determined when the working device 4 is a towed working device.

[0140] Furthermore, the controller 11 determines whether the work device 4 connected to the vehicle body 2 is a lightweight work device or a heavy-duty work device. Then, as shown in Figure 10A, in the forward / reverse switching operation that switches the vehicle body 2 from forward to reverse, if the work device 4 is a heavy-duty work device, the controller 11 determines the first vehicle speed change rate R1b and the first required time T1b as shown in characteristic line L1b, and if the work device 4 is a lightweight work device, the controller 11 determines the first vehicle speed change rate R1a and the first required time T1a as shown in characteristic line L1a.

[0141] Furthermore, as shown in Figure 10B, in the forward / reverse switching operation that switches the vehicle body 2 from reverse to forward, the controller 11 determines the second vehicle speed change rate R2b and the second required time T2b as shown on characteristic line L2b if the work device 4 is a heavy work device, and determines the second vehicle speed change rate R2a and the second required time T2a as shown on characteristic line L2a if the work device 4 is a lightweight work device.

[0142] Specifically, the absolute values ​​of the first vehicle speed change rate R1a and the second vehicle speed change rate R2a, determined when the work device 4 is a lightweight work device, are made larger than the absolute values ​​of the first vehicle speed change rate R1b and the second vehicle speed change rate R2b, determined when the work device 4 is a heavy-duty work device. In addition, the first required time T1a and the second required time T2a, determined when the work device 4 is a lightweight work device, are made shorter than the first required time T1b and the second required time T2b, determined when the work device 4 is a heavy-duty work device.

[0143] Furthermore, the controller 11 uses at least one of the following: the pitch angle of the vehicle body 2 calculated from the detection result of the IMU 21d, which is status information of the work vehicle 1; and the detection result of the laser sensor 22a, which is status information of the surrounding environment of the work vehicle 1; and the image captured by the camera 22c. Based on this, the controller 11 determines at least one of the terrain and area of ​​the location where the vehicle body 2 is located. Alternatively, the controller 11 determines at least one of the terrain and area of ​​the location where the vehicle body 2 is located based on the position determined by the positioning device 23, which is status information of the work vehicle 1, and the map information of the location where the vehicle body 2 is located, which is received by the wide-area communication device 24c of the communication device 24 or stored in the memory 11a. Then, the controller 11 determines the forward / reverse switching characteristics using the characteristic determination unit 11f based on at least one of the terrain and area of ​​the determined location.

[0144] Specifically, the controller 11 determines, based on the status information described above, whether the vehicle 2 is traveling on flat ground or on an incline, and if it determines that the vehicle 2 is traveling on an incline, it further determines whether the vehicle 2 is traveling uphill or downhill.

[0145] The controller 11 then determines the forward / reverse switching characteristics so that the forward / reverse switching operation is performed more quickly when the vehicle body 2 is traveling on flat ground and when the vehicle body 2 is traveling downhill on an incline than when it is traveling uphill on an incline. Specifically, as shown in Figure 10A, in the forward / reverse switching operation to switch the vehicle body 2 from forward to reverse, the controller 11 determines the first vehicle speed change rate R1b and the first required time T1b as shown by characteristic line L1b when the vehicle body 2 is traveling uphill on an incline, and determines the first vehicle speed change rate R1a and the first required time T1a as shown by characteristic line L1a when the vehicle body 2 is traveling on flat ground and when the vehicle body 2 is traveling downhill on an incline.

[0146] Furthermore, as shown in Figure 10B, in the forward / reverse switching operation that switches the vehicle body 2 from reverse to forward, the controller 11 determines the second vehicle speed change rate R2b and the second required time T2b as shown by characteristic line L2b when the vehicle body 2 is traveling uphill, and determines the second vehicle speed change rate R2a and the second required time T2a as shown by characteristic line L2a when the vehicle body 2 is traveling on flat ground or when the vehicle body 2 is traveling downhill.

[0147] Specifically, the absolute values ​​of the first vehicle speed change rate R1a and the second vehicle speed change rate R2a, determined for when vehicle 2 is traveling on flat ground and when it is traveling downhill, are made larger than the absolute values ​​of the first vehicle speed change rate R1b and the second vehicle speed change rate R2b, determined for when vehicle 2 is traveling uphill. In addition, the first required time T1a and the second required time T2a, determined for when vehicle 2 is traveling on flat ground and when it is traveling downhill, are made shorter than the first required time T1b and the second required time T2b, determined for when vehicle 2 is traveling uphill.

[0148] As another example, the absolute values ​​of the first and second vehicle speed change rates R1a and R2a when the vehicle 2 is traveling downhill may be smaller than the absolute values ​​of the first and second vehicle speed change rates R1a and R2a determined when the vehicle 2 is traveling on level ground. Also, the first and second required times T1a and T2a when the vehicle 2 is traveling downhill may be longer than the first and second required times T1a and T2a determined when the vehicle 2 is traveling on level ground.

[0149] Furthermore, when the vehicle body 2 is traveling on level ground, the controller 11 may determine the forward / reverse switching characteristics such that the first required time T1 for switching the vehicle body 2 from forward to reverse is longer than the second required time T2 for switching the vehicle body 2 from reverse to forward, as shown in Figure 8, so that the forward / reverse switching operation of the vehicle body 2 from forward to reverse is performed more slowly than the forward / reverse switching operation from reverse to forward.

[0150] Furthermore, if the controller 11 determines that the vehicle body 2 is traveling downhill, for example Alternatively, as shown in Figure 11, the forward / reverse switching characteristics may be determined such that the second required time T2 when switching the vehicle body 2 from reverse to forward is longer than the first required time T1 when switching the vehicle body 2 from forward to reverse, so that the forward / reverse switching operation of the vehicle body 2 from reverse to forward is performed more slowly than the forward / reverse switching operation from forward to reverse.

[0151] Furthermore, the controller 11 compares the position (position of the vehicle body 2) determined by the positioning device 23 with the field information and determines whether the determined position is in the headland E1 (see Figure 5), which is located between the work area C1 of field H1 and the edge (contour) H2 of field H1, as indicated by the field information received by the wide-area communication device 24c of the communication device 24 or stored in the memory 11a. If the position determined by the positioning device 23 is in the headland E1, the controller 11 calculates the headland width D2 of the headland E1, which is the distance from the work area C1 to the edge H2 of field H1, based on the field information. If the headland width D2 is less than the fourth predetermined value, the controller determines the forward / reverse switching characteristics so that the forward / reverse switching operation is performed more slowly than when the headland width D2 is equal to or greater than the fourth predetermined value. The fourth predetermined value is set to a value smaller than the second predetermined value used to determine the timing of the forward / reverse switching operation described above.

[0152] As shown in Figure 10A, in a forward / reverse switching operation that switches the vehicle body 2 from forward to reverse, the controller 11 determines the first vehicle speed change rate R1b and the first required time T1b as shown on characteristic line L1b if the headboard width D2 is less than the fourth predetermined value, and determines the first vehicle speed change rate R1a and the first required time T1a as shown on characteristic line L1a if the headboard width D2 is greater than or equal to the fourth predetermined value. Furthermore, as shown in Figure 10B, in a forward / reverse switching operation that switches the vehicle body 2 from reverse to forward, the controller 11 determines the second vehicle speed change rate R2b and the second required time T2b as shown on characteristic line L2b if the headboard width D2 is less than the fourth predetermined value, and determines the second vehicle speed change rate R2a and the second required time T2a as shown on characteristic line L2a if the headboard width D2 is greater than or equal to the fourth predetermined value.

[0153] Specifically, the absolute values ​​of the first vehicle speed change rate R1b and the second vehicle speed change rate R2b, which are determined when the pillow width D2 is less than the fourth predetermined value, are made smaller than the absolute values ​​of the first vehicle speed change rate R1a and the second vehicle speed change rate R2a, which are determined when the pillow width D2 is equal to or greater than the fourth predetermined value. In addition, the first required time T1b and the second required time T2b, which are determined when the pillow width D2 is less than the fourth predetermined value, are made longer than the first required time T1a and the second required time T2a, which are determined when the pillow width D2 is equal to or greater than the fourth predetermined value.

[0154] Other conditions besides those related to the status information described above may be set in advance, and the controller 11 may determine the forward / reverse switching characteristics using the characteristic determination unit 11f based on whether or not these other conditions are met.

[0155] For example, the controller 11 may refer to the operating time indicated by the hour meter, which is status information for the work vehicle 1, taking into consideration the wear and depletion of each part such as the running gear 5, electric motor 3, inverter 14, and high-voltage battery 12 used to perform the forward / reverse switching operation of the work vehicle 1. The controller 11 may then determine the forward / reverse switching characteristics (first required time, second required time, first vehicle speed change rate, and second vehicle speed change rate, etc.) using the characteristic determination unit 11f so that when the operating time indicated by the hour meter is greater than or equal to a predetermined time, the forward / reverse switching operation is performed more slowly than when it is less than a predetermined time.

[0156] Furthermore, the controller 11 determines whether the work device 4 connected to the vehicle body 2 is on the ground or not, based on the lifting switch provided on the work vehicle 1 or the image captured by the camera 22c. The controller 11 may then determine the forward / reverse switching characteristics so that when the work device 4 is on the ground, the forward / reverse switching operation is performed more quickly than when it is not on the ground.

[0157] Furthermore, the controller 11 may determine the forward / reverse switching characteristics based on the detection results of the laser sensor 22a, the image captured by the camera 22c, or the positioning position and map information of the positioning device 23, so as to perform the forward / reverse switching operation more quickly when the distance between the vehicle body 2 and an obstacle or the area where the vehicle body 2 is located is greater than or equal to a predetermined value, compared to when it is less than a predetermined value.

[0158] Furthermore, although the above-described embodiment shows an example in which the work device 4 is connected to the rear of the vehicle body 2 via the coupling device 6, work devices such as buckets can be connected to the front of the vehicle body 2 via a front loader or the like.Taking this into consideration, the controller 11 may determine whether the work device 4 is connected to the front or rear of the vehicle body 2 based on at least one of the detection results of the laser sensor 22a, the captured image of the camera 22c, the user interface 20, or the device information input by the communication device 24.The controller 11 may then determine the forward / reverse switching characteristics so that, for example, when the work device 4 is connected to the front of the vehicle body 2, the forward / reverse switching operation is performed more quickly than when it is connected to the rear.

[0159] More specifically, in the forward / reverse switching operation that switches the vehicle body 2 from forward to reverse as shown in Figure 10A, when the work device 4 is connected to the rear of the vehicle body 2, the controller 11 determines the first vehicle speed change rate R1b and the first required time T1b as shown by characteristic line L1b. Also, when the work device 4 is connected to the front of the vehicle body 2, the controller 11 determines the first vehicle speed change rate R1a and the first required time T1a as shown by characteristic line L1a. Furthermore, in the forward / reverse switching operation that switches the vehicle body 2 from reverse to forward as shown in Figure 10B, when the work device 4 is connected to the rear of the vehicle body 2, the controller 11 determines the second vehicle speed change rate R2b and the second required time T2b as shown by characteristic line L2b. Also, when the work device 4 is connected to the front of the vehicle body 2, the controller 11 determines the second vehicle speed change rate R2a and the second required time T2a as shown by characteristic line L2a.

[0160] Any one of the conditions related to the status information described above may be set for work vehicle 1, or two or more conditions may be set.

[0161] Figure 12 is a table showing an example of the relationship between multiple conditions related to status information and the forward / reverse switching characteristics. In the example in Figure 12, the conditions related to the status information of the work vehicle 1 are set as "manned" (occupied), "unmanned" (unoccupied), and "turning" and "moving straight" for the vehicle body 2. The conditions related to the status information of the work device 4 are set as "not connected" and "connected" to the vehicle body 2, the type of work device 4 is "directly mounted", "towing", "heavyweight", and "lightweight", and the connection position of the work device 4 is "forward" and "rear" for the vehicle body 2. The conditions related to the status information of the surrounding environment are set as "flat ground" and "sloping ground" (uphill and downhill) for the terrain where the vehicle body 2 is located, and "narrow" (headland width D2 is less than the fourth predetermined value) and "wide" (headland width D2 is greater than or equal to the fourth predetermined value) for the headland E1 where the vehicle body 2 is located.

[0162] Furthermore, as corresponding values ​​for determining the required times T1 and T2 for the forward and reverse switching operation included in the forward and reverse switching characteristics, the following are set: "fast time T1a, T2a" and "slow time T1b, T2b" shown in Figures 10A and 10B, "coefficient K1" multiplied by the first required time T1, "coefficient K2" multiplied by the second required time T2, and the vehicle speed ranges "forward ~ 0" and "reverse ~ 0" included in each required time T1 and T2. "Forward ~ 0" and "reverse ~ 0" indicate the range in which the vehicle speed change is made quickly.

[0163] If any of the following conditions apply, the controller 11, using the characteristic determination unit 11f, will determine the required times T1 and T2 using corresponding values ​​as shown in Figure 10A and The rapid times T1a and T2a (first values) shown in Figure 10B are determined, respectively. Furthermore, if any of the following conditions apply, the controller 11, using the characteristic determination unit 11f, determines the slower times T1b and T2b (second values) shown in Figures 10A and 10B, respectively, as corresponding values ​​for determining the required times T1 and T2.

[0164] Furthermore, if any of the following conditions apply, the controller 11, using the characteristic determination unit 11f, determines "1.2" (second value) as the "coefficient K1" which is the corresponding value for determining the first required time T1, thereby increasing the first required time T1. Furthermore, if any of the following conditions apply, the controller 11, using the characteristic determination unit 11f, determines "1" (first value) as the "coefficient K1" which is the corresponding value for determining the first required time T1.

[0165] Furthermore, if any of the following conditions apply, the controller 11, using the characteristic determination unit 11f, determines "1" as the "coefficient K2" which is the corresponding value for determining the second required time T2, thereby shortening the second required time T2. Furthermore, if any of the following conditions apply, the controller 11, using the characteristic determination unit 11f, determines "1" as the "coefficient K2" which is the corresponding value for determining the second required time T2, thereby lengthening the second required time T2.

[0166] Furthermore, if any of the following conditions apply, the controller 11, using the characteristic determination unit 11f, decides to change the vehicle speed more quickly within the range "forward ~ 0" (the first value marked with a circle) included in each required time T1 and T2 than within the range "reverse ~ 0" (the second value not marked with a circle). Also, if any of the following conditions apply, the controller 11, using the characteristic determination unit 11f, decides to change the vehicle speed more quickly within the range "reverse ~ 0" included in each required time T1 and T2 than within the range "forward ~ 0".

[0167] However, as shown in Figure 13, for example, if multiple conditions enclosed by an ellipse are met, the corresponding values ​​for determining the required times T1 and T2 are determined as fast times T1a and T2a (first values) and slow times T1b and T2b (second values), respectively, so these corresponding values ​​are not fixed. Also, the "coefficient K1" and "coefficient K2" are determined as "1" (first value) and "1.2" (second value) respectively as corresponding values ​​for determining (calculating) the required times T1 and T2, so these corresponding values ​​are also not fixed. Furthermore, the range for quickly changing the vehicle speed for the required times T1 and T2 is also determined as "forward ~ 0" and "reverse ~ 0" respectively (the one with a circle is the first value, the one without a circle is the second value), so this range is also not fixed. To address this, the controller 11 determines the corresponding values ​​for determining the required times T1 and T2 based on a predetermined selection method.

[0168] For example, the controller 11 determines the success or failure of multiple conditions based on multiple status information and provisionally determines fast times T1a and T2a (first values) and slow times T1b and T2b (second values) as corresponding values ​​for determining the required times T1 and T2 according to the success or failure of each of the multiple conditions. Then, if the provisionally determined multiple corresponding values ​​include both fast times T1a and T2a and slow times T1b and T2b, the controller 11 formally determines the larger of the fast times T1a and T2a and slow times T1b and T2b as the corresponding values ​​for determining the required times T1 and T2 (majority vote method). In the example shown in Figure 13, the controller 11 tentatively determines three fast time intervals T1a and T2a, and four slow time intervals T1b and T2b. Therefore, the slow time intervals T1b and T2b are formally determined as corresponding values ​​for determining the required time intervals T1 and T2.

[0169] Alternatively, if the controller 11 determines that all of the provisionally determined corresponding values ​​are fast times T1a and T2a (first values), it formally determines that fast times T1a and T2a are the corresponding values ​​for determining the required times T1 and T2 (AND method). Also, as shown in Figure 13, if the provisionally determined corresponding values ​​include fast times T1a and T2a and slow times T1b and T2b, the controller 11 formally determines that slow times T1b and T2b are the corresponding values ​​for determining the required times T1 and T2.

[0170] Alternatively, the controller 11 assigns N points (where N is an arbitrary integer, e.g., 3 points) to the corresponding values ​​tentatively determined for dynamic conditions among a plurality of predetermined conditions whose success or failure can change while the vehicle body 2 is in motion, and assigns M points (where M is an arbitrary integer, e.g., 1 point) which are smaller than N points to the corresponding values ​​tentatively determined for static conditions whose success or failure cannot change while the vehicle body 2 is in motion. In the example in Figure 13, "turning," "going straight," "flat ground," "uphill," "downhill," "narrow," and "wide" are dynamic conditions, and "manned," "unmanned," "uncoupled," "directly mounted," "towed," "heavyweight," "lightweight," "forward," and "rearward" are static conditions.

[0171] As shown in Figure 13, if the controller 11 has tentatively determined correspondence values ​​that include fast times T1a, T2a and slow times T1b, T2b, it calculates the total value of points assigned to the fast times T1a, T2a and the total value of points assigned to the slow times T1b, T2b, respectively. Then, the controller 11 formally determines the correspondence value for determining the required times T1, T2 as the one with the larger total value of points between the fast times T1a, T2a and the slow times T1b, T2b (point method).

[0172] In the example shown in Figure 13, the controller 11 provisionally determines fast times T1a and T2a for the static condition "direct mounting" and the dynamic conditions "moving straight" and "flat ground," and calculates the total points for fast times T1a and T2a as 7 points (= 1 point + 3 points + 3 points). The controller 11 also provisionally determines slow times T1b and T2b for the static conditions "manned," "heavyweight," and "rearward," and the dynamic condition "narrow," and calculates the total points for slow times T1b and T2b as 6 points (= 1 point + 1 point + 1 point + 3 points). Since the total points for fast times T1a and T2a are greater than the total points for slow times T1b and T2b, the controller 11 formally determines fast times T1a and T2a as corresponding values ​​for determining the required times T1 and T2.

[0173] The three selection methods described above are just examples, and corresponding values ​​for determining the required times T1 and T2 may be selected using other selection methods. For example, multiple conditions may be assigned priorities, and the controller 11 may select the corresponding value for the condition with the highest priority from among the conditions that are met. The "coefficient K1", "coefficient K2", and the range for quick vehicle speed changes, "forward ~ 0" and "reverse ~ 0", are also formally determined by the controller 11 using one of the three selection methods described above.

[0174] In the embodiment described above, the controller 11 automatically determines the forward / reverse switching characteristics based on the initial vehicle speed, target vehicle speed, and status information using the characteristic determination unit 11f. However, the system may also be configured to allow the operator to arbitrarily input characteristic values ​​to be included in the forward / reverse switching characteristics, for example, via the user interface 20.

[0175] Figure 14 shows an example of the forward / reverse switching characteristic setting screen G1. When an operator, such as the driver of the work vehicle 1, performs a predetermined operation on the user interface 20, the controller 11 displays the forward / reverse switching characteristic setting screen G1 on the display of the user interface 20.

[0176] The settings screen G1 includes input fields J1 to J6 for inputting the first required time T1, first deceleration time T1d, first acceleration time T1i, first vehicle speed change rate R1, first deceleration rate R1d, and first acceleration rate R1i for the forward / reverse switching operation, which switches the vehicle body 2 from forward to reverse. The settings screen G1 also includes input fields J7 to J12 for inputting the second required time T2, second deceleration time T2d, second acceleration time T2i, second vehicle speed change rate R2, second deceleration rate R2d, and second acceleration rate R2i for the forward / reverse switching operation, which switches the vehicle body 2 from reverse to forward. A confirmation key U1 and a cancel key U2 are also provided on the settings screen G1.

[0177] When the operator taps any of the input fields J1 to J12, the controller 11 displays a numeric keypad as a pop-up on the settings screen G1. At this time, the controller 11 may also display the previously set characteristic values ​​in the input fields J1 to J12. When the operator enters any numerical value for the characteristic value corresponding to any of the input fields J1 to J12 that was tapped using the numeric keypad, the controller 11 displays the entered numerical value in the corresponding input field J1 to J12. Then, when the operator taps the confirmation key U1, the controller 11 stores the numerical values ​​displayed in the input fields J1 to J12 as the input values ​​(changed values) for each characteristic value in memory 11a. After this, when an instruction to execute a forward / reverse switching operation is input or when the controller 11 determines that a forward / reverse switching operation should be performed, it determines or changes the forward / reverse switching characteristics based on the characteristic values ​​stored in memory 11a.

[0178] The work vehicle of the embodiment described above has the configuration described in the following items and achieves the effects described therein.

[0179] (Item 1) The work vehicle 1 comprises an electric motor 3 mounted on a vehicle body 2, a travel device 5 that drives the vehicle body 2 using power output from the electric motor 3, a first input device (at least one of a user interface 20, a rotation speed sensor 21c, a steering angle sensor 21b, an IMU 21d, a load sensor 21e, a laser sensor 22a, a camera 22c, a positioning device 23, and a communication device 24) that inputs status information indicating the state of at least one of the work vehicle 1 and the surrounding environment, and a controller 11 that determines the required times T1 and T2 for a forward / reverse switching operation to switch the vehicle body 2 from forward to reverse or from reverse to forward based on the status information, controls the drive of the electric motor 3 over the required times T1 and T2, and executes the forward / reverse switching operation by the travel device 5.

[0180] According to the configuration of item 1 above, the required times T1 and T2 for the forward / reverse switching operation are determined according to the state of at least one of the conditions of the work vehicle 1 and the surrounding environment, and the speed of the forward / reverse switching operation of the work vehicle 1 can be appropriately controlled by these required times T1 and T2. As a result, the forward / reverse switching operation of the work vehicle 1 can be performed stably and appropriately.

[0181] (Item 2) The work vehicle 1 described in Item 1 above is equipped with an inverter 14 that drives an electric motor 3. The controller 11 determines the required times T1 and T2 based on status information input by the first input device while the vehicle body 2 is moving or stopped, and controls the rotation speed and rotation direction of the electric motor 3 by the inverter 14 over the required times T1 and T2 to perform a forward / reverse switching operation.

[0182] According to the configuration of item 2 above, while the vehicle body 2 is moving or stopped, the required time T1 and T2 for the forward / reverse switching operation can be determined according to the state of at least one of the work vehicle 1 and the surrounding environment, and the speed of the forward / reverse switching operation of the work vehicle 1 can be appropriately controlled by the required time T1 and T2.

[0183] (Item 3) The work vehicle 1 described in item 1 or 2 above is equipped with second input devices 10, 24 (forward / reverse lever 10, communication device 24) into which an instruction to execute a forward / reverse switching operation is input. When the execution instruction is input, the controller 11 determines the required times T1 and T2 based on the status information input by the first input device and executes the forward / reverse switching operation over the required times T1 and T2.

[0184] According to the configuration described in item 3 above, when an instruction to perform a forward / reverse switching operation is input by the second input devices 10 and 24, the required times T1 and T2 for the forward / reverse switching operation are determined according to the state of at least one of the work vehicle 1 and the surrounding environment, and the speed of the forward / reverse switching operation of the work vehicle 1 can be appropriately controlled by these required times T1 and T2.

[0185] (Item 4) In the work vehicle 1 described in any of the above items 1 to 3, the controller 11 determines the timing to execute the forward / reverse switching operation based on the status of the work vehicle 1 and the surrounding environment indicated by the status information, determines the required times T1 and T2 at that timing, and executes the forward / reverse switching operation over the required times T1 and T2.

[0186] According to the configuration of item 4 above, the timing for executing the forward / reverse switching operation and the required times T1 and T2 for the forward / reverse switching operation are automatically determined according to the condition of the work vehicle 1 and the surrounding environment. The forward / reverse switching operation is then properly executed at that timing, and the speed of the forward / reverse switching operation can be appropriately controlled by the required times T1 and T2.

[0187] (Item 5) In the work vehicle 1 described in any of Items 1 to 4 above, the first input device includes at least one of the following: a user interface 20 for inputting vehicle information indicating whether or not the work vehicle 1 is an unmanned work vehicle; a communication device 24 for receiving the vehicle information; and a first sensor (occupant sensor) 21a for detecting whether or not there is an occupant in the work vehicle 1. The work vehicle 1 is equipped with a storage device (memory) 11b for storing the vehicle information, and the controller 11 determines whether or not there is an occupant in the work vehicle 1 based on at least one of the vehicle information and the detection result of the first sensor 21a, and sets the required time T1 and T2 determined when there is no occupant to be shorter than the required time T1 and T2 determined when there is an occupant.

[0188] According to the configuration of item 5 above, when there is no occupant on the work vehicle 1, the forward / reverse switching operation can be performed relatively quickly, prioritizing responsiveness, and when there is an occupant on the work vehicle 1, the forward / reverse switching operation can be performed relatively slowly, prioritizing the stability of the work vehicle 1. Furthermore, by performing the forward / reverse switching operation slowly, the impact generated in the work vehicle 1 can be suppressed.

[0189] (Item 6) In the work vehicle 1 described in any of the above items 1 to 5, the first input device includes at least one of the following: second sensors 21b, 21d (steering angle sensor 21b, IMU 21d) that detect at least one of the steering angle and yaw angle of the vehicle body 2, and a positioning device 23 that determines its own position using a satellite positioning system. The controller 11 determines whether the vehicle body 2 is moving in a straight line or turning based on at least one of the detection results of the second sensors 21b, 21d and the time-series data of the position detected by the positioning device 23, and makes the required times T1, T2 determined when the vehicle body 2 is moving in a straight line shorter than the required times T1, T2 determined when the vehicle body 2 is turning.

[0190] According to the configuration of item 6 above, when the work vehicle 1 is moving straight, the forward / reverse switching operation can be performed relatively quickly, prioritizing responsiveness, and when the work vehicle 1 is turning, the forward / reverse switching operation can be performed relatively slowly, prioritizing the stability of the work vehicle 1.

[0191] (Item 7) In the work vehicle 1 described in any of the above items 1 to 6, the first input device includes at least one of the following: a user interface 20 for inputting device information relating to a work device 4 connected to the vehicle body 2; a communication device 24 for receiving the device information; and third sensors 21e, 22a, 22c (load sensor 21e, laser sensor 22a, camera 22c) for detecting the work device 4 connected to the vehicle body 2. The work vehicle 1 is equipped with a storage device 11a for storing the device information. The controller 11 determines whether the work device 4 is connected to the vehicle body 2 based on the detection results of the third sensors 21e, 22a, 22c and at least one of the device information, and sets the required times T1 and T2 determined when the work device 4 is not connected to the vehicle body 2 to be shorter than the required times T1 and T2 determined when the work device 4 is connected to the vehicle body 2.

[0192] According to the configuration of item 7 above, when the work device 4 is not connected to the vehicle body 2, the forward / reverse switching operation can be performed relatively quickly, prioritizing responsiveness, and when the work device 4 is connected to the vehicle body 2, the forward / reverse switching operation can be performed relatively slowly, prioritizing the stability of the work vehicle 1.

[0193] (Item 8) In the work vehicle 1 described in any of Items 1 to 7 above, the first input device includes at least one of a user interface 20 for inputting device information relating to a work device 4 connected to the vehicle body 2, a communication device 24 for receiving the device information, and third sensors 21e, 22a, and 22c for detecting the work device 4 connected to the vehicle body 2. The work vehicle 1 is equipped with a storage device 11a for storing the device information, and the controller 11 determines the type of work device 4 connected to the vehicle body 2 based on the detection results of the third sensors 21e, 22a, and 22c and at least one of the device information, and determines the required times T1 and T2 according to the type of work device 4.

[0194] According to the configuration of item 8 above, the forward / reverse switching operation can be performed relatively quickly or relatively slowly depending on the type of work device 4 connected to the vehicle body 2.

[0195] (Item 9) In the work vehicle 1 described in Item 8 above, the controller 11 determines whether the type of work device 4 is a directly mounted work device supported by the vehicle body 2 or a towed work device towed by the vehicle body 2, based on the detection results of the third sensors 21e, 22a, and 22c and the device information, and makes the required time T1 and T2 determined when the type of work device 4 is a directly mounted work device shorter than the required time T1 and T2 determined when the type of work device 4 is a towed work device.

[0196] According to the configuration of item 9 above, when the direct-mount work device 4 is connected to the vehicle body 2, the forward / reverse switching operation can be performed relatively quickly, prioritizing responsiveness, and when the towed work device 4 is connected to the vehicle body 2, the forward / reverse switching operation can be performed relatively slowly, prioritizing the stability of the work vehicle 1 and the work device 4.

[0197] (Item 10) In the work vehicle 1 described in item 8 or 9 above, the controller 11 determines whether the type of work device 4 is a lightweight work device having a weight less than a predetermined threshold or a heavy-duty work device having a weight equal to or greater than a predetermined threshold, based on the detection results of the third sensors 21e, 22a, and 22c and the device information, and makes the required time T1 and T2 determined when the type of work device 4 is a lightweight work device shorter than the required time T1 and T2 determined when the type of work device 4 is a heavy-duty work device.

[0198] According to the configuration of item 10 above, when a lightweight work device 4 is connected to the vehicle body 2, the forward / reverse switching operation can be performed relatively quickly, prioritizing responsiveness, and when a heavy-duty work device 4 is connected to the vehicle body 2, the forward / reverse switching operation can be performed relatively quickly, prioritizing the stability of the work vehicle 1 and the work device 4. The replacement action can be performed relatively slowly.

[0199] (Item 11) In the work vehicle 1 described in any of the above items 8 to 10, the controller 11 determines whether the work device 4 is connected to the front or rear of the vehicle body 2 based on the detection results of the third sensors 21e, 22a, and 22c and the device information, and makes the required times T1 and T2 determined when the work device 4 is connected to the front of the vehicle body 2 shorter than the required times T1 and T2 determined when the work device 4 is connected to the rear of the vehicle body 2.

[0200] According to the configuration of item 11 above, when the work device 4 is connected to the front of the vehicle body 2, the forward / reverse switching operation can be performed relatively quickly, prioritizing responsiveness, and when the work device 4 is connected to the rear of the vehicle body 2, the forward / reverse switching operation can be performed relatively slowly, prioritizing the stability of the work vehicle 1 and the work device 4.

[0201] (Item 12) In the work vehicle 1 described in any of the above items 1 to 11, the first input device includes at least one of a fourth sensor (IMU) 21d for detecting the pitch angle of the vehicle body 2, a fifth sensor 22a, 22c (laser sensor 22a, camera 22c) for detecting the inclination state of the ground on which the vehicle body 2 is located, and a communication device 24 for receiving map information including the terrain of the place on which the vehicle body 2 is traveling, and also includes a positioning device 23 for determining its own position using a satellite positioning system, the work vehicle 1 is equipped with a storage device 11a for storing the map information, and the controller 11 determines at least one of the terrain and area of ​​the place on which the vehicle body 2 is located based on at least one of the detection results of the fourth sensor 21d, the detection results of the fifth sensors 22a, 22c, and the comparison result obtained by comparing the map information with the position determined by the positioning device 23, and determines the required time T1, T2 based on at least one of the terrain and area of ​​the determined place.

[0202] According to the configuration of item 12 above, the forward / reverse switching operation can be performed relatively quickly or relatively slowly depending on at least one of the terrain and size of the place where the work vehicle 1 is traveling or stopped.

[0203] (Item 13) In the work vehicle 1 described in Item 12 above, the controller 11 determines whether the vehicle body 2 is traveling on level ground or on an incline based on at least one of the detection results of the fourth sensor 21d, the detection results of the fifth sensors 22a and 22c, and the comparison results, and makes the time required when the vehicle body 2 is traveling on level ground shorter than the time required when the vehicle body 2 is traveling on an incline.

[0204] According to the configuration of item 13 above, when the work vehicle 1 is traveling on flat ground, the forward / reverse switching operation can be performed relatively quickly with an emphasis on responsiveness, and when the work vehicle 1 is traveling on an incline, the forward / reverse switching operation can be performed relatively slowly with an emphasis on the stability of the work vehicle 1.

[0205] (Item 14) In the work vehicle 1 described in item 12 or 13 above, the controller 11 determines whether the vehicle body 2 is traveling uphill or downhill on an incline based on at least one of the detection results of the fourth sensor 21d, the detection results of the fifth sensors 22a and 22c, and the matching results, and makes the required time T1 and T2 determined when the vehicle body 2 is traveling uphill longer than the required time T1 and T2 determined when the vehicle body 2 is traveling downhill.

[0206] According to the configuration of item 14 above, when the work vehicle 1 is traveling downhill, the forward / reverse switching operation can be performed relatively quickly, prioritizing responsiveness, and when the work vehicle 1 is traveling uphill, the forward / reverse switching operation can be performed relatively slowly, prioritizing the stability of the work vehicle 1.

[0207] (Item 15) In the work vehicle 1 described in any of the above items 12 to 14, the controller 11 determines whether the vehicle body is traveling on level ground or uphill based on at least one of the detection results of the fourth sensor 21d, the detection results of the fifth sensors 22a and 22c, and the matching results, and makes the required time T1 and T2 determined when the vehicle body 2 is traveling on level ground shorter than the required time T1 and T2 determined when the vehicle body 2 is traveling uphill.

[0208] According to the configuration of item 15 above, when the work vehicle 1 is traveling on flat ground, the forward / reverse switching operation can be performed relatively quickly, prioritizing responsiveness, and when the work vehicle 1 is traveling uphill, the forward / reverse switching operation can be performed relatively slowly, prioritizing the stability of the work vehicle 1.

[0209] (Item 16) In the work vehicle 1 described in any of the above items 1 to 15, the first input device includes at least one of a user interface 20 for inputting field information relating to field H1 and a communication device 24 for receiving field information, and also includes a positioning device 23 for determining its own position using a satellite positioning system, the work vehicle 1 is equipped with a storage device 11a for storing field information, and the controller 11 calculates the headland width D2, which is the distance from the work area C1 to the end H2, when the position determined by the positioning device 23 is in a headland E1 provided between the work area C1 of field H1 and the end H2 of field H1, as indicated by the field information included in the status information, and makes the required time T1, T2 determined when the headland width D2 is less than a predetermined value longer than the required time T1, T2 determined when the headland width D2 is equal to or greater than a predetermined value.

[0210] According to the configuration of item 16 above, when the work vehicle 1 is located on a wide headland E1, the forward / reverse switching operation can be performed relatively quickly, and when the work vehicle 1 is located on a narrow headland E1, the forward / reverse switching operation can be performed relatively slowly to prevent the work vehicle 1 from deviating from the field H1.

[0211] (Item 17) In the work vehicle 1 described in any of the above items 1 to 16, the controller 11 determines whether a predetermined condition is met based on the status information, and determines either a first value or a second value in which the required times T1 and T2 are longer than the first value as a corresponding value for determining the required times T1 and T2 according to the success or failure.

[0212] According to the configuration of item 17 above, the required times T1 and T2 for the forward / reverse switching operation can be determined appropriately and easily based on predetermined conditions relating to at least one of the conditions of the work vehicle 1 and the surrounding environment.

[0213] (Item 18) In the work vehicle 1 described in Item 17 above, the controller 11 determines whether multiple predetermined conditions are met based on multiple status information, and provisionally determines a first value or a second value as one of multiple corresponding values ​​corresponding to the success or failure of each of the multiple predetermined conditions. If the provisionally determined multiple corresponding values ​​include both a first value and a second value, the controller 11 formally determines the larger of the two included first and second values ​​as the corresponding value.

[0214] According to the configuration of item 18 above, even if there is a mix of first and second values ​​as multiple corresponding values ​​for determining the required times T1 and T2 based on multiple predetermined conditions, the one that is more frequent will be selected, so that the required times T1 and T2 for the forward and reverse switching operation can be determined according to the state of the work vehicle 1 and the surrounding environment. Furthermore, the speed of the forward and reverse switching operation of the work vehicle 1 can be appropriately controlled by these required times T1 and T2.

[0215] (Item 19) In the work vehicle 1 described in Item 17 above, the controller 11 determines whether multiple predetermined conditions are met based on multiple status information, and provisionally determines a first value or a second value as multiple corresponding values ​​corresponding to whether each of the multiple predetermined conditions is met, and the provisionally determined multiple If all the corresponding values ​​for a number are the first value, the first value is formally determined as the corresponding value. If the tentatively determined multiple corresponding values ​​include both the first and second values, the second value is formally determined as the corresponding value.

[0216] According to the configuration of item 19 above, when multiple corresponding values ​​for determining the required times T1 and T2 based on multiple predetermined conditions are all provisionally determined to be a first value, the required times T1 and T2 can be shortened based on the first value, and the forward / reverse switching operation of the work vehicle 1 can be executed quickly. Furthermore, when the first and second values ​​are mixed as multiple corresponding values, the required times T1 and T2 can be lengthened based on the second value, and the forward / reverse switching operation of the work vehicle 1 can be executed slowly and stably.

[0217] (Item 20) In the work vehicle 1 described in Item 17 above, the controller 11 determines the success or failure of multiple predetermined conditions based on multiple status information, and provisionally determines a first value or a second value as multiple corresponding values ​​corresponding to the success or failure of each of the multiple predetermined conditions. Among the multiple predetermined conditions, the controller 11 assigns N points to the first value or the second value (corresponding value) provisionally determined for dynamic conditions in which the success or failure may change while the vehicle is in motion, and assigns M points, which are less than N points, to the first value or the second value (corresponding value) provisionally determined for static conditions in which the success or failure cannot change while the vehicle is in motion. N and M are each predetermined integers. If the provisionally determined multiple corresponding values ​​include both a first value and a second value, the controller 11 calculates the total value of the points assigned to the first value and the total value of the points assigned to the second value, and formally determines the corresponding value to be the one with the larger total value of points between the first value and the second value.

[0218] According to the configuration of item 20 above, even if there is a mix of first and second values ​​as multiple corresponding values ​​for determining the required times T1 and T2 based on multiple predetermined conditions, the corresponding value determined by the dynamic conditions rather than the static conditions among the multiple predetermined conditions can be given more weight, and either the first or second value corresponding to the work vehicle 1 and the surrounding environment can be adopted. Then, the speed of the forward and reverse switching operation of the work vehicle 1 can be appropriately controlled by the required times T1 and T2.

[0219] Although the present invention has been described above, the embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0220] 1. Work vehicles 2 car bodies 3 Electric motor 4. Working equipment 5. Traveling device 10. Forward / reverse selector lever (second input device) 11 Controllers 11a Memory (storage device) 14 Inverters 20. User Interface (First Input Device) 21a Crew sensor (first input device, first sensor) 21b Steering angle sensor (first input device, second sensor) 21c rotation speed sensor 21d IMU (1st input device, 2nd sensor, 4th sensor) 21e Load sensor (1st input device, 3rd sensor) 22a Laser sensor (1st input device, 3rd sensor, 5th sensor) 22c Camera (1st input device, 3rd sensor, 5th sensor) 23 Positioning device (first input device) 24. Communication equipment (first input device, second input device) C1 work area D2 Headland width E1 headland H1 Field H2 field edge

Claims

1. The electric motor mounted on the vehicle body, A work vehicle comprising a running device that drives the vehicle body using power output from the electric motor, A first input device that inputs status information indicating the state of at least one of the work vehicle and the surrounding environment, A controller that determines the time required for a forward / reverse switching operation to switch the vehicle body from forward to reverse or from reverse to forward based on the status information, controls the drive of the electric motor for the required time, and executes the forward / reverse switching operation using the running gear, A work vehicle equipped with [a specific feature / equipment].

2. The system includes an inverter that drives the aforementioned electric motor, The work vehicle according to claim 1, wherein the controller determines the required time based on the status information input by the first input device while the vehicle is moving or stopped, and controls the rotation speed and rotation direction of the electric motor by the inverter for the required time to perform the forward / reverse switching operation.

3. The device includes a second input device to which an instruction to execute the forward / reverse switching operation is input, The work vehicle according to claim 1, wherein the controller, when the execution instruction is input, determines the required time based on the status information input by the first input device, and executes the forward / reverse switching operation for the required time.

4. The controller determines the timing for executing the forward / reverse switching operation based on the status of the work vehicle and the surrounding environment indicated by the status information, determines the required time at the timing, and executes the forward / reverse switching operation for the required time, according to claim 1.

5. The first input device is A user interface for inputting vehicle information indicating whether or not the work vehicle is an unmanned work vehicle, A communication device that receives the aforementioned vehicle information, A first sensor detects the presence or absence of an occupant in the work vehicle, Includes at least one of the following: The work vehicle is equipped with a storage device that stores the vehicle information, The aforementioned controller, Based on at least one of the vehicle information and the detection result of the first sensor, it is determined whether or not the occupant is on board the work vehicle. The work vehicle according to claim 1, wherein the time required when the occupant is not on board is shorter than the time required when the occupant is on board.

6. The first input device is A second sensor that detects at least one of the steering angle and yaw angle of the vehicle body, A positioning device that determines its own position using a satellite positioning system, Includes at least one of the following: The aforementioned controller, Based on the detection result of the second sensor and the time-series data of the position detected by the positioning device, it is determined whether the vehicle is moving straight or turning. The work vehicle according to claim 1, wherein the required time determined when the vehicle body is moving straight is shorter than the required time determined when the vehicle body is turning.

7. The first input device is A user interface for inputting device information related to a work device connected to the vehicle body, A communication device that receives the aforementioned device information, A third sensor that detects the work device connected to the vehicle body, Includes at least one of the following: The work vehicle is equipped with a storage device that stores the aforementioned device information, The aforementioned controller, Based on the detection result of the third sensor and at least one of the device information, it is determined whether or not the work device is connected to the vehicle body. The work vehicle according to claim 1, wherein the required time determined when the work device is not connected to the vehicle body is shorter than the required time determined when the work device is connected to the vehicle body.

8. The first input device is A user interface for inputting device information related to a work device connected to the vehicle body, A communication device that receives the aforementioned device information, A third sensor that detects the work device connected to the vehicle body, Includes at least one of the following: The work vehicle is equipped with a storage device that stores the aforementioned device information, The work vehicle according to claim 1, wherein the controller determines the type of work device connected to the vehicle body based on at least one of the detection result of the third sensor and the device information, and determines the required time according to the type of work device.

9. The aforementioned controller, Based on the detection result of the third sensor and at least one of the device information, it is determined whether the type of work device is a directly mounted work device supported by the vehicle body or a towed work device towed by the vehicle body. The work vehicle according to claim 8, wherein the required time determined when the type of work device is the direct-mounted type of work device is shorter than the required time determined when the type of work device is the towed type of work device.

10. The aforementioned controller, Based on the detection result of the third sensor and at least one of the device information, it is determined whether the type of work device is a lightweight work device having a weight below a predetermined threshold or a heavy-duty work device having a weight equal to or greater than the threshold. The work vehicle according to claim 8, wherein the required time determined when the type of work device is the lightweight work device is shorter than the required time determined when the type of work device is the heavy-duty work device.

11. The aforementioned controller, Based on the detection result of the third sensor and at least one of the device information, it is determined whether the work device is connected to the front or rear of the vehicle body. The work vehicle according to claim 8, wherein the required time determined when the work device is connected to the front of the vehicle body is shorter than the required time determined when the work device is connected to the rear of the vehicle body.

12. The first input device is A fourth sensor for detecting the pitch angle of the vehicle body, A fifth sensor detects the inclination state of the ground on which the vehicle body is located, A communication device that receives map information including the terrain of the area where the vehicle is traveling, At least one of the following, A positioning device that determines its own position using a satellite positioning system, Includes, The work vehicle is equipped with a storage device that stores the aforementioned map information, The work vehicle according to claim 1, wherein the controller determines at least one of the terrain and size of the location where the vehicle body is located based on at least one of the detection result of the fourth sensor, the detection result of the fifth sensor, and the comparison result obtained by comparing the map information with the position determined by the positioning device, and determines the required time based on at least one of the terrain and size of the determined location.

13. The aforementioned controller, Based on at least one of the detection results of the fourth sensor, the detection results of the fifth sensor, and the matching results, it is determined whether the vehicle is traveling on a level surface or on an incline. The work vehicle according to claim 12, wherein the required time determined when the vehicle body is traveling on flat ground is shorter than the required time determined when the vehicle body is traveling on an inclined ground.

14. The aforementioned controller, Based on at least one of the detection results of the fourth sensor, the detection results of the fifth sensor, and the matching results, it is determined whether the vehicle is traveling uphill or downhill on an incline. The work vehicle according to claim 12, wherein the required time determined when the vehicle body is traveling uphill is longer than the required time determined when the vehicle body is traveling downhill.

15. The aforementioned controller, Based on at least one of the detection results of the fourth sensor, the detection results of the fifth sensor, and the matching results, it is determined whether the vehicle is traveling on a level surface or traveling uphill on an incline. The work vehicle according to claim 12, wherein the required time determined when the vehicle body is traveling on flat ground is shorter than the required time determined when the vehicle body is traveling uphill on an inclined ground.

16. The first input device is A user interface for inputting field information about the field, A communication device that receives the aforementioned field information, At least one of the following, A positioning device that determines its own position using a satellite positioning system, Includes, The work vehicle is equipped with a storage device that stores the field information, The aforementioned controller, If the position determined by the positioning device is located in the headland between the work area of ​​the field and the edge of the field as indicated in the field information, the headland width, which is the distance from the work area to the edge, is calculated. The work vehicle according to claim 1, wherein the required time determined when the headland width is less than a predetermined value is longer than the required time determined when the headland width is equal to or greater than the predetermined value.

17. The controller determines whether a predetermined condition is met based on the status information, and determines the required time based on the success or failure, using a first value and a value prior to the first value as corresponding values. The work vehicle according to claim 1, which determines either a second value that results in a longer required time, or the second value.

18. The aforementioned controller, Based on the multiple status information, the success or failure of multiple predetermined conditions is determined, and the first or second value is provisionally determined as one of the multiple corresponding values ​​corresponding to the success or failure of each of the multiple predetermined conditions. The work vehicle according to claim 17, wherein if the first value and the second value are included in a plurality of provisionally determined corresponding values, the larger of the first value and the second value included is formally determined as the corresponding value.

19. The aforementioned controller, Based on the multiple status information, the success or failure of multiple predetermined conditions is determined, and the first or second value is provisionally determined as one of the multiple corresponding values ​​corresponding to the success or failure of each of the multiple predetermined conditions. If all of the provisionally determined corresponding values ​​are the first value, the first value is formally determined as the corresponding value. The work vehicle according to claim 17, wherein if the provisionally determined multiple corresponding values ​​include the first value and the second value, the second value is formally determined as the corresponding value.

20. The aforementioned controller, Based on the multiple status information, the success or failure of multiple predetermined conditions is determined, and the first or second value is provisionally determined as one of the multiple corresponding values ​​corresponding to the success or failure of each of the multiple predetermined conditions. N points are assigned to the first or second value that is tentatively determined based on dynamic conditions among the multiple predetermined conditions, where success or failure may change while the vehicle is in motion, and M points, which are smaller than N points, are assigned to the first or second value that is tentatively determined based on static conditions where success or failure cannot change while the vehicle is in motion. The aforementioned N and M are each predetermined integers, The aforementioned controller, If the first value and the second value are included in the multiple provisionally determined corresponding values, calculate the total value of points assigned to the first value and the total value of points assigned to the second value. The work vehicle according to claim 17, wherein the larger of the sum of the points from the first value and the second value is formally determined as the corresponding value.

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