Work vehicle

Abstract

The present application can avoid the concern that the braking operation system for emergency stop does not act normally in the automatic travel of the work vehicle. The work vehicle is provided with: a foot brake that brakes left and right rear wheels; an automatic travel unit that can automatically travel the vehicle; and an electric brake that switches the foot brake to a braking state and a release state, the automatic travel unit having a control section (22Fa) that controls the operation of the electric actuator, the control section (22Fa) performing an operation confirmation process that confirms whether the foot brake normally operates through the operation control of the electric actuator when an automatic travel mode is selected by a manual operation of a mode selection section, and switching to an operation confirmation completion state when the normal operation of the foot brake is confirmed in the operation confirmation process, thereby allowing the travel mode to be switched from a manual travel mode to the automatic travel mode.

Description

Technical Field

[0001] This invention relates to work vehicles equipped with a foot brake for braking the driving mechanism. Background Technology

[0002] In passenger vehicles, there are devices that serve as driving assistance devices and driving assistance methods, namely, devices for emergency braking control in the event of a risk of collision with a preceding vehicle (see, for example, Patent Document 1).

[0003] Patent Document 1: Japanese Patent Application Publication No. 2017-43193

[0004] In recent years, satellite positioning systems (NSS) such as GPS (Global Positioning System) have been used in tractors and other work vehicles to promote automation that enables these vehicles to drive automatically. Further automation of such work vehicles could lead to unmanned operation, requiring a braking system to bring them to an emergency stop while they are automatically moving without human intervention.

[0005] Because work vehicles capable of autonomous operation without human intervention are originally designed to be driven by passengers, there are situations where autonomous operation of the work vehicle cannot be maintained for extended periods. In such cases, if autonomous operation of the work vehicle is implemented, there is a concern that the emergency braking system may malfunction. Summary of the Invention

[0006] In view of the above-mentioned actual situation, the main problem of the present invention is to avoid the concern that the braking system for emergency stops will malfunction during the automatic driving of the work vehicle.

[0007] The first feature of this invention is that, in the work vehicle,

[0008] The operating vehicle is equipped with:

[0009] Foot brake, which brakes the driving device;

[0010] An automatic driving unit that enables the vehicle to drive automatically;

[0011] The mode selection unit is capable of selecting an automatic driving mode in which the vehicle is driven automatically by the aforementioned automatic driving unit; and

[0012] An electric actuator switches the foot brake to a braking state that applies braking to the travel device and a released braking state.

[0013] The aforementioned automatic driving unit has a control unit that controls the operation of the aforementioned electric actuator.

[0014] The control unit is configured such that, when the automatic driving mode is selected by the manual operation of the mode selection unit, it performs an action confirmation process to confirm whether the foot brake is operating normally under the action control of the electric actuator. If the normal operation of the foot brake is confirmed in the action confirmation process, it switches to the action confirmation completion state and allows the switching of the driving mode from the manual driving mode to the automatic driving mode.

[0015] According to this structure, when the work vehicle is capable of automatic driving based on the automatic driving mode, the foot brake is confirmed to operate normally through the action confirmation process beforehand by the action control of the electric actuator.

[0016] Therefore, in automatic driving mode, when the need arises to activate the foot brake through the action control of the electric actuator, the foot brake can be activated normally, thereby enabling the working vehicle to be reliably stopped.

[0017] The second structural feature of the present invention is that,

[0018] The operating vehicle is equipped with:

[0019] A first motion sensor detects the motion of the aforementioned electric actuator; and

[0020] The second motion sensor detects the action of the aforementioned foot brake.

[0021] The aforementioned action confirmation process includes: a first action confirmation process, which confirms whether the electric actuator operates normally based on detection information from the first action sensor; and a second action confirmation process, which confirms whether the foot brake operates normally based on detection information from the second action sensor.

[0022] According to this structure, in the action confirmation process, the action confirmation of the electric actuator that causes the foot brake to operate and the action confirmation of the foot brake are performed separately.

[0023] As a result, action confirmation processing can be performed with high precision, thereby improving the reliability of action confirmation processing.

[0024] The third structural feature of the present invention is that,

[0025] When the aforementioned control unit is about to perform the aforementioned action confirmation process, it performs a pre-condition determination process to determine whether the conditions for starting the action confirmation process are met. If the pre-condition determination process determines that the conditions for starting the aforementioned action confirmation process are met, the aforementioned action confirmation process is performed.

[0026] According to this structure, for example, if the condition for starting the action confirmation process includes the condition that the brake pedal is in the depressed / released position, it is possible to prevent the action confirmation process from being performed when the load on the electric actuator is reduced due to the brake pedal being depressed.

[0027] That is, if the conditions for starting the action confirmation process are set to be the same as those when the foot brake is activated by the electric actuator in actual automatic driving, the reliability of the action confirmation process can be avoided if the action confirmation process is performed under different conditions.

[0028] The fourth structural feature of the present invention is that,

[0029] When the control unit switches to the state where the action confirmation is completed, it performs a validity period determination process to determine whether the validity period of the action confirmation is completed has elapsed. If the validity period of the action confirmation is completed has elapsed in the automatic driving mode, the driving mode is switched from the automatic driving mode to the manual driving mode and the state is switched back to the initial state. If the normal operation of the foot brake is confirmed again through the action confirmation process, the control unit switches back to the state where the action confirmation is completed and allows the switch to the automatic driving mode.

[0030] According to this structure, for example, when the work vehicle is driven automatically for several days, the operation confirmation process is performed periodically. Therefore, when the work vehicle is used for several days, and certain adverse conditions affecting braking operation occur in the electric actuator, foot brake, etc., these conditions can be detected in the operation confirmation process.

[0031] This effectively mitigates the concern that the foot brake may not operate properly when the need arises during automatic driving to activate it via the electric actuator's motion control.

[0032] The fifth structural feature of the present invention is that,

[0033] When the control unit switches to the state where the action confirmation is completed, it performs a validity period determination process to determine whether the validity period of the state where the action confirmation is completed has elapsed. If the validity period of the state where the action confirmation is completed has elapsed in the manual driving mode, it reports that the validity period has elapsed.

[0034] According to this structure, it is possible to notify passengers who manually drive the work vehicle in advance that an action confirmation process is required when switching the driving mode to automatic driving mode.

[0035] Furthermore, in manual driving without the foot brake being activated by the electric actuator, it can prevent the reduction in work efficiency caused by periodic action confirmation. Attached Figure Description

[0036] Figure 1 It is a diagram showing the schematic structure of an automatic driving system.

[0037] Figure 2 It is a block diagram representing the schematic structure of an automated driving system.

[0038] Figure 3 It is a block diagram illustrating the structure related to the safety braking function.

[0039] Figure 4 This is a three-dimensional view showing the main structural components of the braking system, viewed from the upper left rear.

[0040] Figure 5 This is a three-dimensional view showing the main structural components of the braking system, viewed from the upper right rear.

[0041] Figure 6 It is a three-dimensional view showing the main parts of the structure around the brake pedal in the braking system.

[0042] Figure 7 This is a rear view showing the main parts of the structure surrounding the brake pedal in the braking system.

[0043] Figure 8 This is a perspective view taken from the upper right front, showing the main components of the braking system based on an electric motor.

[0044] Figure 9 This is a perspective view taken from the upper right rear, showing the main components of the braking system based on an electric motor.

[0045] Figure 10 This is a right view showing the main components of the braking operation structure based on an electric motor in the braking system.

[0046] Figure 11This is a longitudinal left-hand sectional view showing the main part of the non-operating state of the electric motor-based foot brake in the braking system.

[0047] Figure 12 This is a longitudinal left-hand sectional view showing the main part of the operating state of the electric motor-based foot brake in the braking system.

[0048] Figure 13 It is a graph that shows the relationship between the operating quantity based on the action of the electric motor, the braking force, and the operating load.

[0049] Figure 14 This is a flowchart of the emergency stop control.

[0050] Figure 15 This is a picture showing the home screen of an LCD monitor.

[0051] Figure 16 This is a diagram showing the safety brake check selection screen on an LCD monitor.

[0052] Figure 17 This is a diagram showing a safety brake check screen where the initial check button is displayed as inoperable on an LCD monitor.

[0053] Figure 18 This is a diagram showing a safety brake check screen where the initial check button is displayed as operable on an LCD monitor.

[0054] Figure 19 This is a diagram showing the safety brake inspection screen displaying the status of the inspection process on an LCD monitor.

[0055] Figure 20 This is a diagram showing a safety brake check screen that displays a check failure status on an LCD monitor.

[0056] Figure 21 This is a diagram showing the safety brake check screen displayed on an LCD monitor indicating that the check is complete.

[0057] Figure 22 This is an image showing the start screen of automatic driving on an LCD monitor.

[0058] Figure 23 This is a diagram showing the sequence of initial checks (action confirmation processing).

[0059] Figure 24 This is a state transition diagram that shows the state transition of the safety braking function unit during the initial inspection, etc.

[0060] Figure 25 It is a state transition diagram that shows the state transition of the safety braking function unit under error detection conditions. Detailed Implementation

[0061] Hereinafter, as an example of a way of carrying out the present invention, an embodiment of applying the present invention to a tractor, which is an example of a work vehicle, will be described based on the accompanying drawings.

[0062] Furthermore, this invention can be applied to passenger work vehicles other than tractors, such as passenger lawn mowers, passenger rice transplanters, combine harvesters, transport vehicles, wheel loaders, snowplows, etc.

[0063] like Figures 1-2 As shown, the tractor 1 exemplified in this embodiment is configured to automatically travel in a field or the like, which is an example of a work site, via an automatic driving system for work vehicles. The automatic driving system includes an automatic driving unit 2 mounted on the tractor 1, and a portable communication terminal 3, which is an example of a wireless communication device configured to communicate wirelessly with the automatic driving unit 2. The portable communication terminal 3 can be a tablet-type personal computer, smartphone, or the like, which has a multi-touch display (e.g., an LCD panel) 4 that displays information related to automatic driving.

[0064] like Figure 1 As shown, the tractor 1 has a rotary tiller 6, which is an example of an operating device, connected to its rear via a three-point linkage 5, and is liftable and rotatable. Thus, the tractor 1 is configured as a rotary tiller.

[0065] In addition, at the rear of the tractor 1, instead of the rotary tillage device 6, various operating devices such as plows, disc harrows, cultivators, subsoilers, seeders, spreading devices, and mowing devices can be connected.

[0066] like Figures 1-3As shown, the tractor 1 includes: drivable and steerable left and right front wheels 10 and drivable left and right rear wheels 11 that function as wheeled travel devices; a cab 13 forming a ride-on driver's cab 12; an electronically controlled diesel engine (hereinafter referred to as the engine) 14 with a common rail system; a transmission unit 15 that changes the speed of the power from the engine 14; a fully hydraulic power steering mechanism 16 that steers the left and right front wheels 10 and a braking system 17 that brakes the left and right rear wheels 11; an electronically controlled clutch operating mechanism 19 that hydraulically operates a working clutch that causes the transmission of the rotary tiller 6 to be intermittent; an electronically hydraulically controlled lifting drive mechanism 20 that drives the rotary tiller 6 to rise and fall; an electronically hydraulically controlled rolling direction drive mechanism 21 that drives the rotary tiller 6 in the rolling direction; an on-board control system 22 with various control units; a vehicle status detection device 23 that includes various sensors and switches that detect various settings and operating states of the tractor 1; and a positioning unit 24 that measures the current position and orientation of the tractor 1.

[0067] Alternatively, an electronically controlled gasoline engine with an electronic speed governor can be used for engine 14. An electric power steering system with an electric motor can also be used for power steering mechanism 16.

[0068] like Figure 1 , Figures 3-5 As shown, the driver's unit 12 includes: various control levers such as accelerator lever and gear lever; various control pedals such as accelerator pedal 28 and clutch pedal 29; a steering wheel 30 that can be manually steered left and right via the power steering mechanism 16 to the front wheels 10; a seat 31 for passengers; and a multi-touch LCD monitor 32 that displays various information including information related to autonomous driving and can be input.

[0069] like Figure 1 As shown, the cab 13 is supported by a front frame 34, which is located on the front side of the tractor 1, and a transmission unit 15, which also serves as the rear frame, via shock-absorbing rubber or similar materials. The engine 14 is supported by the front frame 34 via shock-absorbing rubber or similar materials. The engine 14 is covered by an engine hood 35 located on the front side of the tractor 1.

[0070] like Figure 2As shown, the transmission unit 15 includes: an electronically controlled continuously variable transmission (CVT) 36 that changes the speed of power from the engine 14; an electro-hydraulic controlled forward / reverse switching device 37 that switches the power changed by the CVT 36 for forward and reverse use; and a rear wheel differential device that allows differential movement of the left and right rear wheels 11. The CVT 36 is an example of an I-HMT (Integrated Hydro-static Mechanical Transmission), which has higher transmission efficiency than a hydrostatic CVT (HST). The forward / reverse switching device 37 includes a hydraulic clutch for discontinuous forward power, a hydraulic clutch for discontinuous reverse power, and a solenoid valve for controlling the flow of oil relative to these clutches.

[0071] Furthermore, instead of I-HMT, the continuously variable transmission (CVT) 36 can be an HMT (Hydraulic Mechanical Transmission), a hydrostatic CVT (HST), or a belt CVT, which are examples of hydraulic mechanical CVTs. Alternatively, instead of CVT 36, the transmission unit 15 can be an electro-hydraulic controlled stepped transmission that includes multiple hydraulic clutches for shifting speeds and multiple solenoid valves controlling the flow of oil relative to them.

[0072] like Figures 4-7As shown, the braking system 17 includes: left and right brake pedals 40 and parking lever 41 provided in the driver's unit 12; left and right brakes 42 that independently brake the left and right rear wheels 11 respectively; left and right first connecting mechanisms 43 that can be linked to the left and right brake pedals 40 and the left and right brakes 42; parking second connecting mechanism 44 that can be linked to the parking lever 41 and the left and right brakes 42; and an electro-hydraulic controlled first braking operation device 45 that actuates the brake 42 on the inside of the turn in conjunction with steering operation at a set angle or above for the left and right front wheels 10. For the braking system 17, when the passenger depresses any one or both left and right brake pedals 40, pulls the parking lever 41 toward the braking position, or performs steering operation on the left and right front wheels 10 at a set angle or above using the steering wheel 30, the corresponding brake 42 is actuated to brake the corresponding rear wheel 11. Therefore, when both left and right brakes 42 are simultaneously depressed by the left and right brake pedals 40, they function as foot brakes that simultaneously brake the left and right rear wheels 11. When the parking lever 41 is pulled, the left and right brakes 42 function as parking brakes that simultaneously brake the left and right rear wheels 11. When either left or right brake pedal 40 is depressed, or when steering is performed at a set angle or greater than a certain angle by the left or right front wheels 10, the left and right brakes 42 function as side brakes that brake the corresponding left or right rear wheels 11. Each left and right brake 42 contains a compression spring or other force-applying component that returns the brake 42 from a braking state (braking the rear wheels 11) to a released state (releasing the brakes).

[0073] like Figures 2-3 As shown, the vehicle control system 22 includes the following components: an engine control unit 22A, which controls the engine 14; a transmission control unit 22B, which controls the continuously variable transmission 36, the forward / reverse switching device 37, etc.; a steering control unit 22C, which controls the power steering mechanism 16, the first braking operation device 45, etc.; a work device control unit 22D, which controls the work devices such as the rotary tiller 6; a display control unit 22E, which controls the display operation of the liquid crystal monitor 32; an automatic driving control unit 22F, which controls automatic driving; and a non-volatile vehicle storage unit 22G, which stores pre-generated target driving paths for automatic driving, etc. Each control unit 22A to 22F is constructed from an electronic control unit integrating a microcontroller, etc., and various control programs, etc. Figure 3 As shown, the automatic driving control unit 22F and the display control unit 22E are together included in the liquid crystal monitor 32. The control units 22A to 22F are interconnected via CAN (Controller Area Network).

[0074] like Figure 3 As shown, the vehicle condition detection device 23 is a general term for various sensors, switches, etc., provided in various parts of the tractor 1. The vehicle condition detection device 23 includes the following devices: an accelerator sensor, which detects the operation of the accelerator lever and accelerator pedal 28 from the idle position; a gear shift sensor, which detects the operation of the gear shift lever from the zero speed position; a reverse gear sensor, which detects the operating position of the reverse gear lever used for switching between forward and reverse; and left and right brake switches 25, which detect the presence or absence of the left and right brake pedals 40 in the engaged / disengaged position (see reference). Figure 3 The left and right brake sensors 26 detect the amount of operation of the left and right brake pedals 40 in the self-depressed / released position (see reference). Figure 3 The system includes: a rotation sensor that detects the output speed of engine 14; a vehicle speed sensor that detects the speed of tractor 1; and a steering angle sensor that detects the steering angle of the front wheels 10.

[0075] The engine control unit 22A performs engine speed change control, etc. The engine speed change control is based on the detection information from the accelerator sensor and the detection information from the rotation sensor, and changes the engine speed from the idle speed to the speed corresponding to the operation amount of the accelerator lever or accelerator pedal 28.

[0076] The transmission control unit 22B performs the following controls: transmission control, which, based on detection information from the transmission sensor and the vehicle speed sensor, controls the operation of the continuously variable transmission (CVT) 36 to change the speed of the tractor 1 to the speed corresponding to the amount of shift lever operation; forward / reverse switching control, which, based on detection information from the reverse sensor, switches the transmission state of the forward / reverse switching device 37; and brake transmission control, which, based on detection information from each brake sensor 26 and the vehicle speed sensor, controls the operation of the CVT 30 when both left and right brake pedals 40 are simultaneously operated, so that the speed of the tractor 1 decreases from the speed corresponding to the amount of shift lever operation according to the amount of left and right brake pedal 40 depressed. The transmission control includes a deceleration and stop process, which, when the shift lever is operated to the zero-speed position, decelerates the CVT 36 to zero speed, thereby stopping the tractor 1. The braking and transmission control includes a braking deceleration and stop process. When the left and right brake pedals 40 are depressed to their extreme positions, the continuously variable transmission 36 is decelerated to zero speed, thereby stopping the tractor 1.

[0077] like Figures 4-7As shown, in the braking system 17, the left and right brake pedals 40 are arranged side-by-side in the lower front part of the right side of the driver's seat 12. The left and right brake pedals 40 are returned to the released position by the left and right tension springs 46. Each left and right brake pedal 40 has a sleeve portion 40A supported on a rotating shaft 47 extending in the left and right direction below the steering wheel 30, a pedal arm portion 40B extending rearward and downward from the sleeve portion 40A, and a pedal portion 40C mounted on the free end portion of the pedal arm portion 40B. For the right brake pedal 40, its sleeve portion 40A rotates relative to the rotating shaft 47 and has a connecting arm portion 40D extending forward and downward from the sleeve portion 40A. For the left brake pedal 40, its sleeve portion 40A rotates integrally with the connecting arm 48 fixed to the left end of the rotating shaft 47 via the rotating shaft 47.

[0078] like Figures 4-5 As shown, the transmission unit 15 is equipped with left and right brakes 42. Each left and right brake 42 has an operating shaft 49 protruding laterally outward from its front end and an operating arm 50 fixed to the protruding end of the operating shaft 49.

[0079] like Figures 4-7 As shown, each of the left and right first connecting mechanisms 43 includes: a bushing member 52 rotatably supported below the rotating shaft 47 on a left or right fixed shaft 51 extending in the left-right direction; a connecting arm 40D or connecting arm 48 extending over the right brake pedal 40, and a first connecting rod 53 that is vertically elongated to the first arm 52A of the bushing member 52; and a second connecting rod 54 that is longitudinally elongated to the operating arm 50 of the brake 42, extending over the second arm 52B of the bushing member 52. The left first connecting mechanism 43 includes the aforementioned rotating shaft 47 and connecting arm 48. That is, the left and right first connecting mechanisms 43 are configured as rod connections that connect the left and right brake pedals 40 to the left and right brakes 42 via the first connecting rod 53, the second connecting rod 54, etc.

[0080] According to the above structure, for the braking system 17, if only the right brake pedal 40 is depressed, the operating force is transmitted to the operating arm 50 of the right brake 42 via the first connecting mechanism 43 on the right side, thereby switching to a right-side braking state where the right rear wheel 11 is braked by the right brake 42. Subsequently, if the depressing of the right brake pedal 40 is released, the system switches from the right-side braking state to the released state.

[0081] For the braking system 17, if only the left brake pedal 40 is depressed, the operating force is transmitted via the first connecting mechanism 43 on the left to the operating arm 50 of the left brake 42, thereby switching to a left-side braking state where the left rear wheel 11 is braked by the left brake 42. Subsequently, if the depressing operation of the left brake pedal 40 is released, the system switches from the left-side braking state to the released state.

[0082] For the braking system 17, if both left and right brake pedals 40 are depressed, the operating force is transmitted to the operating arms 50 of the left and right brakes 42 via the left and right first connecting mechanisms 43, thereby switching to a braking state where the left and right rear wheels 11 are braked by the left and right brakes 42. Subsequently, if the depressing of the left and right brake pedals 40 is released, the braking state switches to a released state.

[0083] Therefore, when the passenger manually drives the tractor 1, the passenger can operate the steering wheel 30 in the turning direction while simultaneously depressing the brake pedal 40 on the inside of the turn, thereby reducing the turning radius of the tractor 1 during braking and turning. Furthermore, by depressing both the left and right brake pedals 40, the passenger can utilize the braking action of the left and right brakes 42 and the braking and shifting control of the aforementioned shifting control unit 22B to maintain the tractor 1 in a straight-line posture and to brake and decelerate or bring it to a stop.

[0084] like Figures 6-12 As shown, the braking system 17 has a connecting mechanism 55, which can be switched between a connected state connecting the left and right brake pedals 40 and a disengaged state. The connecting mechanism 55 includes: an operating lever 56 movably supported on the right brake pedal 40 in the left-right direction; a compression spring 57 that applies force to the left end of the operating lever 56 protruding towards the left brake pedal 40; and a guide plate 58 that guides the guided portion 56A of the operating lever 56. A J-shaped guide hole 58a is formed in the guide plate 58, guiding the guided portion 56A of the operating lever 56 throughout the connected and disengaged positions. A through hole 40E is formed in the left brake pedal 40 for the left end of the operating lever 56 to be inserted when the guided portion 56A of the operating lever 56 is in the connected position (see reference). Figure 8 , Figures 11-12 ).

[0085] According to the above structure, for the connecting mechanism 55, if the operating lever 56 is operated so that the guided portion 56A of the operating lever 56 is in the connected position, the left end of the operating lever 56 is inserted into the through hole 40E of the left brake pedal 40, thereby switching to the connected state of connecting the left and right brake pedals 40, and this connected state is maintained by the compression spring 57. For the connecting mechanism 55, if the operating lever 56 is operated so that the guided portion 56A of the operating lever 56 is in the released position, the left end of the operating lever 56 is pulled out from the through hole 40E of the left brake pedal 40, thereby switching to the released state of releasing the connection of the left and right brake pedals 40, and this released state is maintained by the compression spring 57.

[0086] Therefore, when the tractor 1 is manually driven by the passenger in the field, the passenger can operate the control lever 56 to switch the coupling mechanism 55 to the disengaged state, thereby enabling necessary braking and turning while driving in the field. Furthermore, when the tractor 1 is manually driven by the passenger outside the field, the passenger can operate the control lever 56 to switch the coupling mechanism 55 to the engaged state, thereby avoiding concerns about unnecessary braking and turning while driving outside the field.

[0087] In the braking system 17, the parking lever 41 is disposed adjacent to the left side of the driver's seat 31 of the driver's unit 12. The parking lever 41 is configured to switch between two positions: an upper braking position where the left and right brakes 42 are switched to the braking state, and a lower release position where the left and right brakes 42 are switched to the release state. The parking lever 41 is activated by a parking switch included in the vehicle status detection device 23, which detects operations to the braking position.

[0088] like Figures 4-5 As shown, the second connection mechanism 44 for parking includes: left and right control cables 59; an equalizer unit 60 that connects one end of the internal cable of each of the left and right control cables 59 to the parking lever 41; and left and right chain link plates 61 and left and right connecting pins 62 that connect the other end of the left and right internal cables to the operating arms 50 of the left and right brakes 42. That is, the second connection mechanism 44 is configured as a cable connection type that connects the parking lever 41 to the left and right brakes 42 via the left and right control cables 59, etc. The left and right chain link plates 61 have elongated holes through which the connecting pins 62, which are fixed to the left and right operating arms 50, pass. These elongated holes function as a means to allow displacement of the left and right operating arms 50 relative to the left and right chain link plates 61 as the left and right brake pedals 40 are depressed.

[0089] According to the above structure, for the braking system 17, if the parking lever 41 is pulled from the lower release position to the upper brake position and held in the brake position, the operating force is transmitted to the operating arms 50 of the left and right brakes 42 via the second connecting mechanism 44, thereby switching to a parking brake state where the left and right rear wheels 11 are braked by the left and right brakes 42 and this braking state is maintained. Subsequently, if the parking lever 41 is pushed from the upper brake position to the lower release position and held in the release position, the parking brake state is switched to the release state.

[0090] like Figure 6 As shown, in the left and right first connecting mechanisms 43, an elongated hole 53a with a relatively long vertical length is formed at the lower end of each first connecting rod 53, and a connecting pin 63 fixed to the first arm portion 52A of the bushing component 52 passes through the elongated hole 53a. Figures 3-5 As shown, for the left and right first connecting mechanisms 43, when the left and right brakes 42 are switched from the released state to the parking brake state by pulling the parking lever 41, in conjunction with this switch, the left and right second connecting rods 54 are pulled backward and the second arms 52B of the left and right bushing components 52 swing backward. In conjunction with this swinging displacement, the first arms 52A of the left and right bushing components 52 swing upward. At this time, the elongated holes 53a of each first connecting rod 53 function as a passage to allow the left and right first arms 52A to swing upward relative to the left and right first connecting rods 53. Thus, when the left and right brakes 42 are switched to the parking brake state by pulling the parking lever 41, the reduced operability caused by the linkage of the left and right brake pedals 40 is avoided.

[0091] like Figures 4-7 As shown, in the braking system 17, the first braking operating device 45 includes: a hydraulic unit 64 for an automatic brake, having two hydraulic cylinders and two solenoid valves corresponding to the left and right brakes 42; a pair of push-pull linkages 65 pushed and pulled by the hydraulic unit 64; a pair of crank arms 66 that swing about a longitudinal axis in conjunction with the pair of push-pull linkages 65; left and right control cables 67 extending from the pair of crank arms 66 toward the left and right bushing components 52; left and right chain link plates 68 and left and right connecting pins 69 connecting the front ends of the inner cables 67A in the left and right control cables 67 to the third arm portions 52C of the left and right bushing components 52. Oil from a hydraulic pump driven by power from the engine 14 is supplied to the hydraulic unit 64. The left and right chain link plates 68 have elongated holes 68a through which connecting pins 69 fixed to the left and right third arms 52C pass. The elongated holes 68a function as a means to allow the left and right third arms 52C to swing relative to the left and right chain link plates 68 as the left and right brake pedals 40 are depressed or the parking lever 41 is pulled.

[0092] like Figure 2 As shown, the braking system 17 includes a steering control unit 22C. The steering control unit 22C performs automatic braking control. When the automatic braking selection switch on the driver's unit 12 is operated and the automatic braking mode is selected, the steering control unit 22C controls the operation of the hydraulic unit 64 in the first braking operation device 45 based on the detection of the steering angle sensor, thereby operating the left and right brakes 42. During automatic braking control, when the steering angle of the left and right front wheels 10 is less than a set angle, the steering control unit 22C maintains each solenoid valve of the hydraulic unit 64 in a discharge state, thereby maintaining the left and right hydraulic cylinders in a contracted state and keeping the left and right brakes 42 in a released state. Furthermore, if the steering angle of the left and right front wheels 10 becomes greater than or equal to a set angle, the solenoid valve corresponding to the inner rear wheel 11 is switched to a supply state, thereby extending the hydraulic cylinder corresponding to the inner rear wheel 11 and maintaining the inner brake 42 in a braking state.

[0093] According to the above structure, when the automatic braking mode is selected for manual driving, the braking system 17 maintains the left and right brakes 42 in a released state via the first braking operation device 45 while the steering angle of the left and right front wheels 10 based on the steering wheel 30 rotation operation is less than a set angle. Thus, the turning state of the tractor 1 is maintained in a normal turning state where the tractor 1 turns with a turning radius corresponding to the steering angle of the left and right front wheels 10. Furthermore, if the steering angle of the left and right front wheels 10 based on the steering wheel 30 rotation operation becomes a set angle or higher, the first braking operation device 45 switches the brake 42 on the inside of the turn to a braking state. Thus, the turning state of the tractor 1 is switched to a braking turning state where the tractor 1 turns with a turning radius smaller than that in the normal turning state. Subsequently, if the steering angle of the left and right front wheels 10 based on the steering wheel 30 rotation operation is less than the set angle, the first braking operation device 45 switches the left and right brakes 42 in a released state. Thus, the turning state of the tractor 1 is switched back to the aforementioned normal turning state.

[0094] That is, during manual driving based on the passenger's driving, if the passenger selects the automatic braking mode, then when the left and right front wheels 10 are turned to a angle greater than a set angle, even if the passenger does not depress the brake pedal 40 on the inside of the turn, the braking system 17 automatically switches the turning state of the tractor 1 to normal turning state and braking turning state, based on whether the left and right front wheels 10 are less than or greater than the set angle. As a result, the passenger can easily perform small turns of the tractor 1 simply by turning the steering wheel 30.

[0095] like Figure 6 As shown, in each of the left and right first connecting mechanisms 43, as described above, an elongated hole 53a is formed at the lower end of the first connecting rod 53, which functions as a fusion section. Therefore, even when the left and right brake pedals 40 are connected by the connecting mechanism 55, the first brake operating device 45 can activate the brake 42 on the inside of the turn when the left and right front wheels 10 are turned to a set angle or higher, thereby switching the turning state of the tractor 1 to the braking turning state.

[0096] The positioning unit 24 includes a satellite navigation device that uses GPS (Global Positioning System), an example of a Navigation Satellite System, to measure the current position and orientation of the tractor 1, and an inertial measurement unit (IMU) that measures the attitude and orientation of the tractor 1 using a three-axis gyroscope and three-directional accelerometers. Positioning methods using GPS include DGPS (Differential GPS) and RTK-GPS (Real-Time Kinematic GPS). In this embodiment, RTK-GPS, suitable for positioning moving objects, is used. Therefore, as... Figure 1 As shown, a base station 73 capable of RTK-GPS-based positioning is set up at a known location around the field.

[0097] like Figures 1-2 As shown, tractor 1 and base station 73 are respectively equipped with receivers from GPS satellite 74 (see reference). Figure 1 The positioning unit 24 includes GPS antennas 75 and 76 that transmit radio waves, and communication modules 77 and 78 that enable wireless communication of various data, including positioning data between the tractor 1 and the base station 73. Thus, the satellite navigation device of the positioning unit 24, based on positioning data obtained by receiving radio waves from GPS satellite 74 via GPS antenna 75 on the tractor side and GPS antenna 76 on the base station side, can accurately measure the current position and orientation of the tractor 1. Furthermore, the positioning unit 24 includes a satellite navigation device and an inertial measurement unit, thereby enabling high-precision measurement of the tractor 1's current position, orientation, and attitude angles (yaw, roll, and pitch).

[0098] In this tractor 1, the inertial measurement device of the positioning unit 24, the GPS antenna 75, and the communication module 77 are included. Figure 1The antenna unit 79 shown is located in the upper left and right center positions of the front side of the cab 13.

[0099] like Figure 2 As shown, the portable communication terminal 3 includes: a terminal control unit 80 that integrates an electronic control unit such as a microcontroller and various control programs; and a communication module 81 capable of wireless communication of various data, including positioning data, with the communication module 77 on the tractor side. The terminal control unit 80 includes: a display control unit 80A that controls the operation of the display unit 4; a driving path generation unit 80B that generates a target driving path for automatic driving; and a non-volatile terminal storage unit 80C that stores the target driving path generated by the driving path generation unit 80B.

[0100] In the target travel path, in addition to multiple work path sections arranged parallel to the working width of tractor 1 at constant intervals, and multiple non-work turning path sections that connect the ends and beginnings of adjacent work path sections in the travel sequence, it also includes appropriate engine speed, appropriate vehicle speed, tractor 1 travel direction, front wheel steering angle in the turning path section, and tractor 1 stopping position, etc., set according to the driving mode of tractor 1 in various travel path sections.

[0101] like Figure 3 As shown, the automatic driving control unit 22F receives detection information from various sensors, switches, etc., included in the vehicle status detection device 23 via the transmission control unit 22B, steering control unit 22C, etc. Thus, the automatic driving control unit 22F can monitor various setting states and operating states of each part in the tractor 1.

[0102] When the tractor 1's driving mode is switched to automatic driving mode, the automatic driving control unit 22F starts to obtain the current position of the tractor 1 through the positioning unit 24 and automatically drives the tractor 1 along the target driving path when the user, such as a passenger or an outside manager, operates the display unit 4 of the portable communication terminal 3 and indicates the start of automatic driving.

[0103] The automatic driving control based on the automatic driving control unit 22F includes: automatic engine control processing that sends automatic driving control commands related to the engine 14 to the engine control unit 22A; automatic transmission control processing that sends automatic driving control commands related to the continuously variable transmission 36, forward / reverse switching device 37, etc., to the transmission control unit 22B; automatic steering control processing that sends automatic driving control commands related to steering to the steering control unit 22C; and automatic operation control processing that sends automatic driving control commands related to the rotary tillage device 6, etc., to the operation device control unit 22D.

[0104] In the automatic control processing for the engine, the automatic driving control unit 22F sends to the engine control unit 22A an engine speed change command that instructs the engine speed to change based on the appropriate engine speed included in the target driving path, and an engine stop command that instructs the engine 14 to stop based on the fulfillment of engine stop conditions.

[0105] In the automatic control processing for transmission, the automatic driving control unit 22F sends to the transmission control unit 22B a transmission operation command that instructs the continuously variable transmission 36 to perform transmission operation based on an appropriate vehicle speed included in the target driving path, a forward / backward switching command that instructs the forward / backward switching device 37 to perform forward / backward switching operation based on the direction of travel of the tractor 1 included in the target driving path, and a neutral switching command that instructs the forward / backward switching device 37 to switch to a neutral state based on the establishment of a driving power cut-off condition.

[0106] In the automatic control processing for steering, the automatic driving control unit 22F sends steering control commands to the steering control unit 22C, which are based on the front wheel steering angle and other parameters included in the target driving path, to control the steering of the left and right front wheels 10.

[0107] In the automatic control processing for operation, the automatic driving control unit 22F sends an operation start command to the operation device control unit 22D, which instructs the rotary tiller 6 to switch to the operation state based on the operation start point included in the target driving path, and an operation stop command, which instructs the rotary tiller 6 to switch to the non-operation state based on the operation stop point included in the target driving path.

[0108] Furthermore, regarding the aforementioned engine stop condition and driving power cut-off condition, the automatic driving control unit 22F, for example, determines that the engine stop condition and driving power cut-off condition are met based on various information from the vehicle status detection device 23, such as when it detects an abnormality in the transmission control unit 22B, such as a transmission control malfunction that causes a deviation between the appropriate vehicle speed and the speed of the tractor 1, or when it detects an abnormality in the CAN communication between the transmission control unit 22B and the steering control unit 22C.

[0109] The engine control unit 22A executes automatic engine speed change control, which automatically changes the engine speed, and automatic engine stop control, which automatically stops the engine 14, based on various control commands related to the engine 14 sent from the automatic driving control unit 22F through the above-mentioned automatic engine control processing.

[0110] The transmission control unit 22B executes various control commands related to the continuously variable transmission (CVT) 36 and the forward / reverse switching device 37, sent from the automatic driving control unit 22F via the aforementioned automatic transmission control processing. These commands include automatic transmission control (automatically controlling the operation of the CVT 36), automatic forward / reverse switching control (automatically controlling the operation of the forward / reverse switching device 37), and automatic neutral switching control (automatically setting the forward / reverse switching device 37 to neutral by cutting off transmission to the left and right front wheels 10 and left and right rear wheels 11). The automatic transmission control includes, for example, an automatic deceleration and stop process. This process decelerates the CVT 36 to zero speed when the appropriate vehicle speed within the target travel path is zero, thus stopping the tractor 1.

[0111] The steering control unit 22C executes automatic steering control to control the left and right front wheels 10 by controlling the operation of the power steering mechanism 16 to perform steering operation based on the steering operation command sent from the automatic driving control unit 22F through the above-mentioned automatic steering control processing, and automatic braking and turning control to activate the first braking operation device 45 and activate the brake 42 on the inside of the turn when the left and right front wheels 10 are turned to a set angle or above.

[0112] The work device control unit 22D controls the operation of the lifting drive mechanism 20 and the clutch operating mechanism 19 based on various control commands related to the rotary tiller 6 sent from the automatic driving control unit 22F through the aforementioned automatic control processing for work. This includes automatic work start control, which lowers the rotary tiller 6 to the working height and initiates operation, and automatic work stop control, which stops the rotary tiller 6 and raises it to a non-working height. Furthermore, in the work state where the rotary tiller 6 is lowered to the working height and initiates operation, the work device control unit 22D performs the following controls: automatic tillage depth maintenance control, which, based on the detection of a tillage depth sensor that detects the tillage depth performed by the rotary tiller 6, controls the operation of the lifting drive mechanism 20 to maintain the tillage depth of the rotary tiller 6 at a set depth; and automatic tilt angle maintenance control, which, based on the detection of a tilt sensor that detects the tilt angle of the tractor 1 and the acceleration sensor of an inertial measurement device, controls the operation of the rolling direction drive mechanism 21 to maintain the tilt posture of the rotary tiller 6 in the rolling direction at a set posture (e.g., a horizontal posture).

[0113] That is, the aforementioned automatic driving unit 2 includes a power steering mechanism 16, a clutch operating mechanism 19, a lifting drive mechanism 20, a rolling direction drive mechanism 21, an on-board control system 22, a vehicle status detection device 23, a positioning unit 24, and a communication module 77. Furthermore, by properly operating these components, the tractor 1 can automatically drive along the target path with high precision and can appropriately perform tillage based on the rotary tiller 6. Additionally, in the event of an abnormality in the transmission control unit 22B or a CAN communication malfunction in the tractor 1, the tractor 1 can automatically stop moving.

[0114] like Figure 2 , Figures 4-5 , Figures 8-11 As shown, the braking system 17 includes an electrically operated second brake operating device 100. This electrically operated second brake operating device 100 activates the left and right brakes 42 as safety brakes by operating the left and right brake pedals 40 connected by the connecting mechanism 55. Figure 3 As shown, the automatic driving control unit 22F includes a safety braking function unit 22Fa, which controls the operation of the second braking operation device 100 to enable the left and right brakes 42 to function as safety brakes.

[0115] like Figures 8-11 As shown, the second brake operating device 100 is disposed adjacent to the right side of the right brake pedal 40 in the driver's compartment 12. The second brake operating device 100 includes: an operable body 101 connected to the right brake pedal 40; an electric actuator 102 that operates the operable body 101 in the front-rear direction; and a fusion section 103 between the right brake pedal 40 and the electric actuator 102, which allows the right brake pedal, etc., to be displaced relative to the electric actuator 102 as the brake pedal 40 is depressed.

[0116] like Figures 8-12As shown, the operated body 101 includes: a first component 104 and a second component 105 connected to the pedal arm 40B of the brake pedal 40 on the right side; a damper 107 connected to the second component 105 in the vertical direction via a connecting pin 106 extending horizontally; and a chain link plate 108 connected to the damper 107 in the longitudinal direction, which is adjustable in position. Furthermore, the chain link plate 108 has an elongated hole 108a in the longitudinal direction that functions as a passageway 103. The electric actuator 102 uses an electric motor with a worm gear reducer 102A. The electric motor 102 is switched between a forward rotation state (outputting forward rotational force), a reverse rotation state (outputting reverse rotational force), and a stop state (stopping the output of rotational force) by the control operation of the steering control unit 22C. Between the operated body 101 and the worm gear reducer 102A of the electric motor 102, there is a reduction gear set 111 having a small-diameter input gear 109 and a large-diameter output gear 110, which further reduces the power from the worm gear reducer 102A; and a connecting pin 112, which connects the outer periphery of the output gear 110 in the reduction gear set 111 to the operated body 101 via a fusion portion 103. The connecting pin 112 is fixed to the outer periphery of the output gear 110 while passing through the elongated hole 108a of the chain link plate 108. The connecting pin 112 is moved from the non-operating position (refer to) where the right brake pedal 40 (right brake 42) is not operated by the forward rotation power from the electric motor 102. Figures 8-11 Move to the maximum operating position when the operating amount of the right brake pedal 40 (right brake 42) is set to the maximum (refer to...). Figure 12 The connecting pin 112 moves from the maximum operating position to the non-operating position by reverse power from the electric motor 102. The non-operating position of the connecting pin 112 is set such that when the brake pedal 40 on the right side is in the depressed position, the connecting pin 112 is located at the front end of the elongated hole 101a.

[0117] According to the above structure, when the right brake pedal 40 is depressed, the forward movement of the operated body 101 relative to the connecting pin 112 is permitted through the opening of the elongated hole 108a (fusing part 103) in the chain link plate 108. As a result, in manual driving of the tractor 1 driven by a passenger, when the right or left brake pedal 40 is depressed, the braking operation of the right or left brake 42, which is linked to the depressing operation, can be smoothly performed without obstruction by the electric motor 102 thanks to the action of the fusing part 103.

[0118] Furthermore, with the left and right brake pedals 40 connected by the connecting mechanism 55, switching the electric motor 102 to the forward rotation state allows the left and right brake pedals 40 to move to their maximum depressed position, thereby switching the left and right brakes 42 to the braking state. Conversely, switching the electric motor 102 to the reverse rotation state allows the left and right brake pedals 40 to move to the release position, thereby switching the left and right brakes 42 to the release state.

[0119] A first limit switch 113 is provided in the non-operating position of the connecting pin 112, which detects the arrival of the connecting pin 112 to the non-operating position based on the action of the electric motor 102. A second limit switch 114 is provided in the maximum operating position of the connecting pin 112, which detects the arrival of the connecting pin 112 to the maximum operating position based on the action of the electric motor 102. When the left and right brake pedals 40 are connected by the connecting mechanism 55, the non-operating position of the connecting pin 112 is the release position for releasing the braking of the left and right brakes 42, and the maximum operating position of the connecting pin 112 is the braking position for maximizing the braking of the left and right brakes 42. Thus, the first limit switch 113 functions as a release switch that detects the arrival of the connecting pin 112 to the release position based on the action of the electric motor 102. The second limit switch 114 functions as a brake switch that detects the arrival of the connecting pin 112 to the braking position based on the action of the electric motor 102. Furthermore, the release switch 113 and the brake switch 114 function as the first motion sensors for detecting the operation of the electric motor 102.

[0120] like Figure 3 As shown, the release switch 113 and the brake switch 114, along with the left and right brake switches 25 and the left and right brake sensors 26, are included in the vehicle condition detection device 23. The vehicle condition detection device 23 includes a linkage switch that is in the open state when the left and right brake pedals 40 are connected by the linkage mechanism 55.

[0121] For the steering control unit 22C, when the linkage switch is open, if the left and right brake switches 25 detect the presence of the left and right brake pedals 40 in the depressed / released position, and the detection values ​​of the left and right brake sensors 26 indicate that the left and right brake pedals 40 are in the depressed / released position, then the left and right brakes 42 can be detected as being in the released state. For the steering control unit 22C, when the linkage switch is open, if the left and right brake switches 25 do not detect the presence of the left and right brake pedals 40 in the depressed / released position, and the detection values ​​of the left and right brake sensors 26 indicate that the left and right brake pedals 40 are in the maximum depressed position, then the left and right brakes 42 can be detected as being in the braking state. That is, the left and right brake switches 25 and the left and right brake sensors 26 function as second action sensors for detecting the movement of the left and right brakes 42 when the left and right brake pedals 40 are connected by the linkage mechanism 55.

[0122] According to the above structure, when the left and right brake pedals 40 are connected by the connecting mechanism 55, the steering control unit 22C controls the operation of the electric motor 102 based on the detection of the left and right brake switches 25, the detection values ​​of the left and right brake sensors 26, the detection of the release switch 113, and the detection of the brake switch 114, thereby reliably switching from the release state to the braking state and from the braking state to the release state of the left and right brakes 42.

[0123] like Figures 8-12 As shown, the second braking operating device 100 has a housing 116 mounted on the base plate (an example of a vehicle's fixed part) 38 of the driver's compartment 12. The housing 116 includes a base plate 117 detachably bolted to the base plate 38, a left housing 118 bolted to the base plate 38 and the base plate 117, a first support plate 119 welded to the inner side of the left housing 118, a second support plate 120 mounted at predetermined intervals to the side wall of the left housing 118, and a right housing 121 bolted to the left housing 118. The housing 116 forms a storage space between the left housing 118 and the right housing 121.

[0124] In the housing 116, three stepped bolts 122 extending to the right from its side wall are fixed to the left housing 118, and the second support plate 120 is mounted to the side wall of the left housing 118 via these stepped bolts 122. The stepped bolt 122 located at the center of the side wall is used to rotatably support the support shaft 123 of the output gear 110. On the side wall of the left housing 118, guide holes 118a for guiding connecting pins 112, extending to both the release and braking positions, are formed in an arc shape centered on the support shaft 123. The electric motor 102 is mounted to the first support plate 119 using three bolts 124. An input gear 109, meshing with and linked to the output gear 110, is mounted on the output shaft of the worm gear reducer 102A in the electric motor 102. The second support plate 120 is configured such that one end functions as a first receiving portion 120A for receiving the connecting pin 112 when it reaches the release position, and the other end functions as a second receiving portion 120B for receiving the connecting pin 112 when it reaches the braking position. Furthermore, a release switch 113 is installed at one end of the second support plate 120, and a brake switch 114 is installed at the other end of the second support plate 120.

[0125] According to the above structure, in the second brake operation device 100, the electric motor 102, the reduction gear set 111, the release switch 113, and the brake switch 114 are housed in the housing 116. Thus, the housing 116, the electric motor 102, the reduction gear set 111, the release switch 113, and the brake switch 114 can be detachably mounted on the base plate 38 as a drive unit in an integrated manner. Furthermore, after the drive unit is installed, the operated body 101 connected to the right brake pedal 40 and the output gear 110 on the drive unit side are connected via the fusion portion 103 and the connecting pin 112 to a state where the operated body 101 can be operated by the electric motor 102. Therefore, the second brake operation device 100 can be assembled on the driver's unit 12, allowing the left and right brakes 42 to be operated by the second brake operation device 100.

[0126] That is, without making significant changes to the structure of the driver's unit 12, the second brake operating device 100 can be easily assembled to the driver's unit 12, thereby making it possible to retrofit the second brake operating device 100 to the tractor 1. As a result, the assembly of the second brake operating device 100 to the tractor 1 becomes easier, and maintenance such as replacement of the second brake operating device 100 in case of malfunction is also easier.

[0127] like Figures 8-10As shown, the first receiving portion 120A and the second receiving portion 120B of the second support plate 120 function as movement limiting portions that restrict the movement range of the connecting pin 112 between the release position and the braking position. The movement range of the connecting pin 112 is set to the range in which the connecting pin 112 moves across an imaginary straight line L1 and throughout the release and braking positions. This imaginary straight line L1 passes through the connecting pin 106, which serves as the connection point between the operated body 101 and the brake pedal 40 on the right side, and the support shaft 123, which serves as the rotation center of the output gear 110.

[0128] According to the above structure, when the second braking operating device 100 actuates the left and right brakes 42, firstly, the forward rotational power from the electric motor 102 is transmitted to the output gear 110, causing the output gear 110 to rotate in the braking direction. As a result, the connecting pin 112 moves from the released position toward the braking position in an arc. At this time, as... Figure 13 As shown, the braking force A of the left and right brakes 42 increases according to the amount of movement of the connecting pin 112 from the clearance region, including the release position, to the braking position. On the other hand, regarding the operating load B applied to the electric motor 102, as the braking force A of the left and right brakes 42 increases, the reaction forces generated inside the left and right brakes 42 from various components such as friction plates increase. In addition, the left and right brake pedals 40 are reset to the release position due to the tension force of the left and right tension springs 46. Therefore, in the first range of movement from the connecting pin 112 after passing through the clearance region to crossing the imaginary straight line L1, the closer the connecting pin 112 is to the imaginary straight line L1, the heavier the operating load B applied to the electric motor 102. On the other hand, the closer the connecting pin 112 is to the imaginary straight line L1, the angle θ between the connecting line L2 connecting the connecting pin 112 and the rotation center of the output gear 110 and the operated body 101 (refer to...) Figure 11The narrower the connecting pin 112, the less effective the reaction forces from the left and right brakes 42 and the tension forces from the left and right tension springs 46 applied to the left and right brake pedals 40 become as forces to return the connecting pin 112 to the released position. Therefore, the increase in the operating load B applied to the electric motor 102 decreases. Subsequently, if the connecting pin 112 crosses the imaginary straight line L1, the reaction forces from the left and right brakes 42 and the tension forces from the left and right tension springs 46 switch to assisting the braking operation of the left and right brakes 42 based on the electric motor 102. Therefore, in the second movement range from when the connecting pin 112 crosses the imaginary straight line L1 to when it reaches the braking position, the further the connecting pin 112 moves from the imaginary straight line L1 and closer to the braking position, the lighter the operating load B applied to the electric motor 102. Furthermore, when the connecting pin 112 reaches the braking position, its movement in the braking direction is restricted by the second receiving part 120B. It is then forced to move in the braking direction by the reaction force from the left and right brakes 42 and the tension force from the left and right tension springs 46. Thus, when the connecting pin 112 crosses the imaginary straight line L1 and reaches the second movement range, for example, in the event of damage to the worm gear reducer 102A in the electric motor 102 or damage to the output gear 110, the reaction force from the left and right brakes 42 and the tension force from the left and right tension springs 46 displace the connecting pin 112 to the braking position and maintain it there. Therefore, the left and right brakes 42 can be maintained in a braking state, and the tractor 1 can be kept in a stopped state.

[0129] As a result, during the braking operation of the left and right brakes 42 based on the second braking operation device 100, in order to reduce the operating load B applied to the electric motor 102 and to stop the tractor 1 by the action of the second braking operation device 100, the tractor 1 can be kept in a stopped state regardless of the damage to the worm gear reducer 102A in the electric motor 102, the loss of the output gear 110, etc.

[0130] like Figure 3 As shown, the safety braking function unit 22Fa monitors the operating status of each part of the tractor 1 and the communication status with each part based on various detection information input from the vehicle status detection device 23 via the transmission control unit 22B, steering control unit 22C, etc. In the aforementioned automatic driving mode, the safety braking function unit 22Fa detects an abnormality inside the vehicle based on the detection information from the vehicle status detection device 23, or receives information from an emergency stop remote controller 90 (see example 3), which is a portable communication terminal 3 or a wireless communication device. Figure 2In the event of an emergency stop command, the system executes the action of controlling the electric motor 102 to switch the left and right brakes 42 from the released state to the braking state in an emergency stop control. Therefore, as... Figure 2 As shown, the tractor 1 is equipped with an emergency stop communication antenna 91 for receiving emergency stop commands sent from the emergency stop remote controller 90.

[0131] The abnormalities inside the vehicle include the following: the engine speed drops below the set lower limit value that may cause the engine to stall; in the automatic transmission control of the transmission control unit 22B, there is a control failure such as the tractor 1's speed deviating from the appropriate speed; and in the CAN communication, there is a communication failure caused by a broken wire, etc.

[0132] In addition, abnormalities inside the vehicle may include situations such as: in the automatic steering control of the steering control unit 22C, a control malfunction occurs, such as the current position of the tractor 1 measured by the positioning unit 24 deviating from the target driving path.

[0133] Therefore, the safety braking function unit 22Fa, in emergency stop control, such as Figure 14 As shown in the flowchart, the following determination processes are performed: First determination process (step #1), which determines whether the engine speed has dropped below a set lower limit value that may cause engine stall based on detection information from the rotation sensor for engine speed detection included in the vehicle status detection device 23; Second determination process (step #2), which determines whether a control malfunction such as the tractor 1 deviating from an appropriate speed has occurred in the transmission control unit 22B based on detection information from the vehicle speed sensor and the like included in the vehicle status detection device 23; Third determination process (step #3), which determines whether a communication malfunction has occurred in CAN communication based on detection information from the CAN communication anomaly detection unit included in the vehicle status detection device 23; and Fourth determination process (step #4), which determines whether an emergency stop command has been received from the portable communication terminal 3 or the emergency stop remote controller 90. Furthermore, in the first determination process (step #1), if the engine speed decreases, if a control failure occurs in the transmission control unit 22B in the second determination process (step #2), if a communication failure occurs in the CAN communication in the third determination process (step #3), or if an emergency stop command is obtained in the fourth determination process (step #4), an emergency stop process (step #5) to bring the tractor 1 to an emergency stop and an emergency stop notification process (step #6) to notify the emergency stop are performed.

[0134] During emergency stop processing, the safety braking function unit 22Fa sends an engine stop command to the engine control unit 22A and a safety braking action command to the steering control unit 22C, causing the left and right brakes 42 to activate as safety brakes. During emergency stop processing, the safety braking function unit 22Fa deselects the automatic driving mode and switches the driving mode from automatic to manual. During emergency stop notification processing, the safety braking function unit 22Fa activates the emergency stop indicator lights and other notification devices 83 (see reference 83) on the tractor 1. Figure 2 The system performs the action and sends an emergency stop notification command to the portable communication terminal 3.

[0135] The engine control unit 22A executes the aforementioned automatic engine stop control based on the engine stop command from the automatic driving control unit 22F, thereby automatically stopping the engine 14.

[0136] The steering control unit 22C activates the electric motor 102 according to the safety braking action command from the safety braking function unit 22Fa, switching the left and right brakes 42 from the released state to the braking state, thereby stopping the tractor 1.

[0137] The portable communication terminal 3 performs emergency stop notification processing, such as switching the display screen of the display unit 4 to the emergency stop notification screen, based on the emergency stop notification command from the automatic driving control unit 22F.

[0138] According to the above structure, when the tractor 1 is driven automatically, the left and right brake pedals 40 are connected by the connecting mechanism 55. In case of abnormalities such as the engine speed dropping below the set lower limit, malfunction in the transmission control unit 22B, or communication failure in CAN communication, the engine 14 can be stopped automatically, and the left and right brakes 42 can be activated automatically as safety brakes, thereby stopping the tractor 1.

[0139] As a result, in automatic driving mode, in the event of the aforementioned abnormality occurring inside the vehicle, even in an unmanned driving state where the tractor 1 is driving automatically without human intervention, the tractor 1 can be quickly braked to a stop and maintained in a stopped state. Furthermore, when the rotary tiller 6 is operating, the engine 14 can be stopped and the operation of the rotary tiller 6 can be stopped.

[0140] Furthermore, unlike the electro-hydraulic controlled first brake operating device 45 which uses oil from a hydraulic pump driven by engine power to actuate the left and right brakes 42, the electric motor 102 can actuate the left and right brakes 42 and maintain the braking state even when the engine 14 stops and the hydraulic pressure drops. Therefore, even when the engine control unit 22A stops the engine 14 according to the engine stop command from the automatic driving control unit 22F, the tractor 1 can still be maintained in a braked stopped state.

[0141] As a result, even if the emergency stop position of tractor 1 is a slope inclined in the direction of travel of tractor 1, the worry of tractor 1 accidentally going downhill can be avoided.

[0142] After performing the aforementioned emergency stop procedure, the safety braking function unit 22Fa, by operating the push-button switch (an example of an operating tool) 84 provided on the driving unit 12 (see reference...) Figure 2 When the power is disconnected by the shutdown operation of the tractor 14 and then reconnected by the opening operation of the push-button switch 84, an emergency stop release process is performed. During the emergency stop release process, the safety brake function unit 22Fa sends an engine stop release command to the engine control unit 22A and a safety brake release command to the steering control unit 22C. Based on the engine stop release command from the safety brake function unit 22Fa, the engine control unit 22A allows the engine 14 to start. Based on the safety brake release command from the safety brake function unit 22Fa, the steering control unit 22C actuates the electric motor 102, thereby switching the left and right brakes 42 from the braking state to the released state, thus releasing the tractor 1 from braking.

[0143] Therefore, when the tractor 1 is brought to an emergency stop by the control action of the safety braking function unit 22Fa, the tractor 1 can be maintained in an emergency stop state while the power is temporarily disconnected by the operation of the push-button switch 84 until it is reconnected. Furthermore, when the power is reconnected by the operation of the push-button switch 84, the engine 14 can be started, releasing the brake stop of the tractor 1. This allows the passenger to start the engine 14 and manually drive the tractor 1. As a result, the tractor 1 can be moved to a safe location, repair shop, etc., by manual driving.

[0144] like Figure 15As shown, the main screen 32A of the LCD monitor 32 displays a mode selection button (mode selection unit) 32a that can rotate to enable the automatic driving mode. When the automatic driving mode is selected via the mode selection button 32a, the automatic driving control unit 22F performs a condition fulfillment determination process. This process determines whether all conditions for switching the tractor 1's driving mode from manual to automatic are met. If all conditions are met, the automatic driving control unit 22F sends a message to the portable communication terminal 3 indicating that the tractor 1's driving mode has been switched from manual to automatic, and that automatic driving can begin via the portable communication terminal 3. If not all conditions are met, the automatic driving control unit 22F continues the condition fulfillment determination process until all conditions are met or the cancel button displayed on the LCD monitor 32 is operated.

[0145] Among the conditions for switching the driving mode to automatic driving mode, in addition to the completion of various setting operations required for the automatic driving of tractor 1, such as setting the engine speed for automatic driving based on the operation of the accelerator lever and setting the vehicle speed for automatic driving based on the operation of the gear lever, it also includes confirming normal operation in the initial check (action confirmation process) to confirm whether the left and right brakes 42 are operating normally as safety brakes. That is, in order to switch the driving mode to automatic driving mode, an initial check needs to be performed in advance to confirm that the left and right brakes 42 are operating normally as safety brakes.

[0146] The initial check is included in the control operation of the safety braking function unit 22Fa. Upon confirmation of the successful completion of normal operation based on the initial check, the safety braking function unit 22Fa transitions to the initial check completion state (operation confirmation completion state). Figure 24 (See Check_OK). A validity period is set for the initial inspection completion state. In this embodiment, the validity period for the initial inspection completion state is set to the same day. Therefore, when the safety braking function unit 22Fa transitions to the initial inspection completion state, it stores the aforementioned transition date in the vehicle storage unit 22G.

[0147] In addition, the effective period for the initial inspection completion status can be set in various ways, such as from the date of conversion to a certain number of days, from the time of conversion to a certain number of hours, or from the converted driving distance to the set driving distance.

[0148] For the initial check to be performed, all of the conditions shown in 1 to 9 below (conditions for starting the action confirmation process) must be met.

[0149] Condition 1: The steering control unit 22C is functioning normally, controlling the movement of the electric motor 102, which enables the left and right brakes 42 to function as safety brakes.

[0150] Condition 2: The transmission control unit 22B, which monitors detection information from the left and right brake switches 25 and the left and right brake sensors 26, is functioning normally.

[0151] Condition 3: Normal CAN communication with steering control unit 22C.

[0152] Condition 4: Normal CAN communication with transmission control unit 22B.

[0153] Condition 5: Based on the detection information from the left and right brake switches 25 and the left and right brake sensors 26 input via the transmission control unit 22B, it is detected that the left and right brake pedals 40 are in the depress / release position.

[0154] Condition 6: The reverse gear lever is detected to be in a neutral position based on the detection information from the reverse gear sensor input via the transmission control unit 22B.

[0155] Condition 7: The parking lever 41 is not in the braking position, based on the detection information from the parking switch input via the transmission control unit 22B.

[0156] Condition 8: Based on the detection information from the linkage switch input via the steering control unit 22C, it is detected that the left and right brake pedals 40 are connected by the linkage mechanism 55.

[0157] Condition 9: The vehicle speed is detected to be zero based on the detection information from the vehicle speed sensor input via the transmission control unit 22B.

[0158] The following is based on Figures 15-25 The description explains the state transition of the safety braking function unit 22Fa during the initial inspection.

[0159] Safety braking function unit 22Fa is controlled by push-button switch 84 (see reference). Figure 2 The opening operation connects the power supply, thus establishing the initial state. Figure 24 (As shown in Start). In the initial state, a determination is made to check whether the effective period has elapsed after the initial implementation of the state.

[0160] In the initial state, if the release switch 113 detects that the connecting pin 112 operated by the electric motor 102 has reached the release position, and the brake switch 114 detects that the connecting pin 112 has reached the brake position, the safety braking function unit 22Fa determines that any one of the electric motor 102, the release switch 113, and the brake switch 114 is malfunctioning, and thus switches to the error detection state. Figure 24 (as shown in Err_Detection).

[0161] In the initial state, if the release switch 113 does not detect the connection pin 112 reaching the release position, and the initial check completion period has elapsed, the safety braking function unit 22Fa switches to the brake release recovery operation state. Figure 24 As shown in Rev_Start, the steering control unit 22C is instructed to release the left and right brakes 42 based on the operation of the electric motor 102. Thus, the steering control unit 22C performs the release operation of the left and right brakes 42 based on the operation of the electric motor 102. Through this release operation, if the left and right brakes 42 were activated as safety brakes by the safety brake function unit 22Fa when the button was previously on, the left and right brakes 42 can be returned to the released state.

[0162] In the initial state, the safety braking function unit 22Fa, through Figure 15 When the mode selection button 32a in the home screen 32A is operated to select the automatic driving mode, a pre-condition determination process is performed to determine whether all the conditions 1 to 9 mentioned above are met.

[0163] In the pre-condition determination process, if one of the conditions 1 to 9 is not met, the safety braking function unit 22Fa switches to a pre-condition met standby state. Figure 24 As shown in Check_PreStandby), and converts the display screen of the LCD monitor 32 to... Figure 16 The safety brake check selection screen 32B is shown.

[0164] In the pre-condition determination process, the safety braking function unit 22Fa switches to the initial check standby state if all conditions 1 to 9 are met. Figure 24 As shown in the Check_Standby, and converts the display screen of the LCD monitor 32 to Figure 16 The safety brake check selection screen 32B is shown.

[0165] In the initial state, if the safety braking function unit 22Fa does not detect the arrival of the connecting pin 112 to the release position during the period when the initial inspection is completed but the release switch 113 does not detect the arrival of the connecting pin 112 to the release position, it will switch to the inspection completed brake release recovery operation state. Figure 24The system displays OK_Rev and instructs the steering control unit 22C to release the left and right brakes 42 based on the operation of the electric motor 102. Thus, the steering control unit 22C performs the release operation of the left and right brakes 42 based on the operation of the electric motor 102. This release operation allows the left and right brakes 42 to return to the released state if, in the previous button-on state, the safety brake function unit 22Fa activated the left and right brakes 42 as safety brakes.

[0166] During the judgment process, if the initial inspection completion state is valid and the release switch 113 detects that the connecting pin 112 has reached the release position, the safety braking function unit 22Fa switches to the aforementioned initial inspection completion state and changes the display screen of the LCD monitor 32 to [the specified state]. Figure 22 The automatic driving start screen 32D shown allows for the switching of driving modes from manual driving mode to automatic driving mode.

[0167] When the safety braking function unit 22Fa is in the pre-condition established standby state, and the initial inspection is selected by operating the inspection selection button 32b in the safety braking inspection selection screen 32B, the display screen of the LCD monitor 32 is switched to... Figure 17 The safety brake check screen 32C is shown. Furthermore, in this safety brake check screen 32C, as... Figure 17 As shown, the initial check button 32c is displayed in gray, thereby indicating that the initial check cannot be started by operating the initial check button 32c.

[0168] When the safety braking function unit 22Fa is in the standby state with the preconditions met, if the release switch 113 detects that the connecting pin 112 has reached the release position and the brake switch 114 detects that the connecting pin 112 has reached the braking position, it determines that one of the electric motor 102, the release switch 113 and the brake switch 114 has malfunctioned, and thus switches to the above-mentioned error detection state.

[0169] When the safety braking function unit 22Fa is in the standby state with the preconditions met, if the release switch 113 does not detect the arrival of the connecting pin 112 to the release position, it switches to the above-mentioned brake release recovery operation state and instructs the steering control unit 22C to release the left and right brakes 42 based on the operation of the electric motor 102.

[0170] When the safety braking function unit 22Fa is in the precondition-established standby state, and the release switch 113 detects the arrival of the connecting pin 112 to the release position based on the operation of the electric motor 102, and the brake switch 114 does not detect the arrival of the connecting pin 112 to the braking position caused by the operation of the electric motor 102, under the condition that all conditions 1 to 9 are met, it switches to the aforementioned initial check standby state, and the initial check button 32c changes its display state on the safety braking check screen 32C. Figure 18 The normal display state shown indicates that the initial check can be selected by operating the initial check button 32c.

[0171] When the safety braking function unit 22Fa is in the pre-condition established standby state, if the release switch 113 detects that the connecting pin 112 has reached the release position and the brake switch 114 does not detect that the connecting pin 112 has reached the braking position, and if one of the conditions 1 to 9 is not met, it maintains the pre-condition established standby state and switches the display screen of the LCD monitor 32 to [a different state]. Figure 17 The safety brake check screen 32C is shown. Furthermore, in this safety brake check screen 32C, the following is displayed: Figure 17 The initial check button 32c is shown as gray, indicating that the initial check cannot be selected by operating the initial check button 32c.

[0172] When the safety braking function unit 22Fa detects that the connecting pin 112 has reached the release position during the initial check standby state, and the brake switch 114 detects that the connecting pin 112 has reached the braking position, it determines that one of the electric motor 102, the release switch 113, and the brake switch 114 is malfunctioning, and thus switches to the above-mentioned error detection state.

[0173] When the safety braking function unit 22Fa is in the initial check standby state, if the release switch 113 does not detect the arrival of the connecting pin 112 to the release position, it switches to the above-mentioned brake release recovery operation state and instructs the steering control unit 22C to release the left and right brakes 42 based on the operation of the electric motor 102.

[0174] When the safety brake function unit 22Fa is in the initial check standby state, if the release switch 113 detects that the connecting pin 112 has reached the release position, but the brake switch 114 does not detect that the connecting pin 112 has reached the brake position, for example, if any of the conditions 1 to 9 are not met due to manual operation of the left or right brake pedal 40 or the reverse gear lever, it switches to the aforementioned pre-condition met standby state, and the initial check button 32c is changed from its display state on the safety brake check screen 32C to... Figure 17 The gray display indicates that the initial check cannot be selected by operating the initial check button 32c.

[0175] When the safety braking function unit 22Fa is in the initial check standby state, and the initial check button 32c is operated, it switches to the brake action check state. Figure 24 As shown in the Check), and as Figure 19 The initial check is shown in the safety brake check screen 32C.

[0176] When the safety braking function unit 22Fa is in the braking action check state, it instructs the steering control unit 22C to perform braking operations on the left and right brakes 42 based on the operation of the electric motor 102. As a result, the steering control unit 22C performs braking operations on the left and right brakes 42 based on the operation of the electric motor 102.

[0177] In the braking action check state, if the release switch 113 detects that the connecting pin 112 has reached the release position and the brake switch 114 detects that the connecting pin 112 has reached the braking position, or if the brake switch 114 does not detect that the connecting pin 112 has reached the braking position even after the prescribed braking action check time has elapsed, the safety braking function unit 22Fa determines that any one of the electric motor 102, the release switch 113, and the brake switch 114 is abnormal, and thus switches to the above-mentioned error detection state.

[0178] In the brake operation check state, if any of the conditions 1 to 9 are not met due to manual operation of the left or right brake pedal 40 or reverse gear lever, the safety brake function unit 22Fa switches to the initial check failure state. Figure 24 As shown in Check_NG), and as Figure 20 The safety brake check screen 32C displays an initial check failure. Furthermore, if a predetermined display time elapses after the transition to the initial check failure state, the safety brake function unit 22Fa returns to the aforementioned initial state, and the display screen of the LCD monitor 32 changes to... Figure 16 The safety brake check selection screen 32B is shown. Furthermore, the safety brake function unit 22Fa... Figure 16 When the inspection selection button 32b on the safety brake inspection selection screen 32B is operated, the system switches to the aforementioned pre-condition met standby state, and the display screen of the LCD monitor 32 is switched to... Figure 17 The safety brake check screen shown is 32C.

[0179] In the brake action check state, if the release switch 113 does not detect the connecting pin 112 reaching the release position, but the brake switch 114 detects the connecting pin 112 reaching the braking position, and the left and right brake switches 25 detect the left and right brake pedals 40 moving from the release position, and the left and right brake sensors 26 detect the left and right brake pedals 40 reaching the maximum position, then it is determined that the left and right brake pedals 40 have been operated to the maximum position, and the left and right brakes 42 are switched to the braking state. Furthermore, based on this determination, the system switches to the release action check standby state. Figure 24 The system displays Check_Rev_Wait and instructs the steering control unit 22C to stop the braking operation of the left and right brakes 42 based on the operation of the electric motor 102. Thus, the steering control unit 22C terminates the braking operation of the left and right brakes 42 based on the operation of the electric motor 102.

[0180] When the safety braking function unit 22Fa is in the standby state for release action check, if the release switch 113 detects that the connecting pin 112 has reached the release position, or if the brake switch 114 does not detect that the connecting pin 112 has reached the brake position, it determines that any one of the electric motor 102, the release switch 113, and the brake switch 114 has malfunctioned, and switches to the above-mentioned error detection state.

[0181] When the safety braking function unit 22Fa is in the standby state for disengagement operation checks, if any of the conditions 1 to 9 are not met due to manual operation of the left or right brake pedals 40 or the reverse gear lever, it switches to the aforementioned initial check failure state, and if... Figure 20 The safety brake check screen 32C displays an initial check failure. Furthermore, if a predetermined display time elapses after the transition to the initial check failure state, the safety brake function unit 22Fa returns to the aforementioned initial state, and the display screen of the LCD monitor 32 changes to... Figure 16 The safety brake check selection screen 32B is shown. Furthermore, the safety brake function unit 22Fa... Figure 16 When the inspection selection button 32b on the safety brake inspection selection screen 32B is operated, the system switches to the aforementioned pre-condition met standby state, and the display screen of the LCD monitor 32 is switched to... Figure 17 The safety brake check screen shown is 32C.

[0182] When the safety braking function unit 22Fa is in the release action check standby state, if the release switch 113 does not detect the connecting pin 112 reaching the release position, but the brake switch 114 detects the connecting pin 112 reaching the braking position, or the left and right brake switches 25 detect the left and right brake pedals 40 moving from the released position, and the left and right brake sensors 26 detect the left and right brake pedals 40 reaching the maximum depressed position, and a predetermined standby time has elapsed, it switches to the release action check state. Figure 24 As shown in Check_Rev).

[0183] When the safety braking function unit 22Fa is in the release operation check state, it instructs the steering control unit 22C to release the left and right brakes 42 based on the operation of the electric motor 102. As a result, the steering control unit 22C performs the release operation of the left and right brakes 42 based on the operation of the electric motor 102.

[0184] In the release action check state, if the release switch 113 detects the arrival of the release position of the connecting pin 112 and the brake switch 114 detects the arrival of the connecting pin 112 to the brake position, or if the release switch 113 fails to detect the arrival of the connecting pin 112 to the release position even after the prescribed release action check time has elapsed, the safety braking function unit 22Fa determines that any one of the electric motor 102, the release switch 113, and the brake switch 114 is malfunctioning, and thus switches to the above-mentioned error detection state.

[0185] When the safety braking function unit 22Fa is in the deactivation check state, for example, if any of the conditions 1 to 9 are not met due to manual operation of the left or right brake pedal 40 or reverse gear lever, it switches to the aforementioned initial check failure state, and as... Figure 20 As shown, the safety brake check screen 32C displays an initial check failure. Furthermore, if a predetermined display time elapses after the transition to the initial check failure state, the safety brake function unit 22Fa transitions from the initial check failure state to the aforementioned initial state, and the display screen of the LCD monitor 32 changes accordingly. Figure 16 The safety brake check selection screen 32B is shown. Furthermore, the safety brake function unit 22Fa... Figure 16 When the inspection selection button 32b on the safety brake inspection selection screen 32B is operated, the system switches to the aforementioned pre-condition met standby state, and the display screen of the LCD monitor 32 is switched to... Figure 17 The safety brake check screen shown is 32C.

[0186] In the release operation check state, if the release switch 113 detects that the connecting pin 112 has reached the release position, but the brake switch 114 does not detect that the connecting pin 112 has reached the braking position, and the left and right brake switches 25 and the left and right brake sensors 26 detect that the left and right brake pedals 40 have reached the depress-release position, then it is determined that the left and right brake pedals 40 have been operated to the depress-release position, and the left and right brakes 42 are switched to the release state. Furthermore, based on this determination, the steering control unit 22C is instructed to stop the release operation of the left and right brakes 42 based on the operation of the electric motor 102. Thus, the steering control unit 22C ends the braking operation of the left and right brakes 42 based on the operation of the electric motor 102. Moreover, the safety brake function unit 22Fa transitions to the initial check success state. Figure 24 As shown in Check_Comp), such as Figure 21 The initial check is shown as completed on the safety brake check screen 32C.

[0187] When the safety brake function unit 22Fa is in the initial check successful state, the initial check completion display on the safety brake check screen 32C continues for a predetermined time. Furthermore, if the predetermined time has elapsed, it switches to the initial check completion state (action confirmation completion state). Figure 24 The Check_OK shown will be displayed, and the screen on the LCD monitor 32 will be switched to... Figure 22 The automatic driving start screen 32D shown allows the switching of driving modes from manual driving mode to automatic driving mode.

[0188] Furthermore, after the safety braking function unit 22Fa is switched to the initial inspection completion state, for example, if various setting operations required for the automatic driving of the tractor 1 are performed, such as setting the engine speed for automatic driving based on the accelerator lever and setting the vehicle speed for automatic driving based on the gear lever, then all the conditions for switching the driving mode to automatic driving mode are met. Moreover, in the state where all conditions are met, the display on... Figure 22 When the automatic driving start button 32d on the automatic driving start screen 32D is operated, the automatic driving control unit 22F switches the driving mode of the tractor 1 from manual driving mode to automatic driving mode and sends a message to the portable communication terminal 3 that the driving mode of the tractor 1 has been switched to automatic driving mode, thereby enabling automatic driving based on the operation of the portable communication terminal 3 to begin.

[0189] That is, when the driving mode is switched to automatic driving mode and the tractor 1 drives automatically, the left and right brakes 42 are confirmed to operate normally as safety brakes through prior action confirmation. Therefore, in automatic driving mode, in the event of the aforementioned abnormality occurring inside the vehicle, the left and right brakes 42 can operate normally as safety brakes, and the tractor 1 can be reliably stopped.

[0190] Furthermore, as can be seen from the above description, the initial inspection (action confirmation process) includes: a first action confirmation process, which confirms whether the electric motor 102 operates normally based on the detection information from the release switch (first action sensor) 113 and the brake switch (first action sensor) 114 that detect the action of the electric motor 102; and a second action confirmation process, which confirms whether the left and right brakes 42 operate normally based on the detection information from the left and right brake switches (second action sensors) 25 and the left and right brake sensors (second action sensors) 26 that detect the action of the left and right brakes 42.

[0191] Therefore, in the initial check (action confirmation process) to confirm whether the left and right brakes 42 are functioning properly as safety brakes, the action confirmation of the electric motor 102 that causes the left and right brakes 42 to function as safety brakes is performed separately, as is the action confirmation of the left and right brakes 42 functioning as safety brakes. As a result, the initial check can be performed with high precision, and the reliability of the initial check can be improved.

[0192] Furthermore, when performing an initial inspection, the safety braking function unit 22Fa first performs a pre-condition determination process, and begins the initial inspection only when all the aforementioned conditions for starting the initial inspection are met. This avoids, for example, situations where the load applied to the electric motor 102 during the initial inspection is too low due to actions such as depressing or disengaging the left and right brake pedals 40, thus reducing the reliability of the initial inspection, or where the initial inspection is incomplete due to abnormalities in the transmission control unit 22B, CAN communication, etc.

[0193] As described above, a valid period is set for the initial inspection completion state. Therefore, the safety braking function unit 22Fa performs the aforementioned period elapsed determination process in the initial inspection completion state. Furthermore, if the valid period has elapsed during the period elapsed determination process, as... Figure 24 The diagram shows the transition from the initial check completed state to the initial state.

[0194] At this time, if the driving mode is automatic driving mode, the safety braking function unit 22Fa switches the driving mode from automatic driving mode to manual driving mode and prohibits switching back to automatic driving mode. Additionally, the safety braking function unit 22Fa switches the display screen of the LCD monitor 32 to... Figure 16 The safety brake check selection screen 32B is shown. Furthermore, in Figure 16 When the inspection selection button 32b on the safety brake inspection selection screen 32B is operated, the safety brake function unit 22Fa performs an initial inspection through the aforementioned state transition, and when it transitions to the initial inspection completed state, the display screen of the LCD monitor 32 is changed to... Figure 22 The automatic driving start screen 32D shown allows for the switching of driving modes from manual driving mode to automatic driving mode.

[0195] Therefore, for example, if the tractor 1 is driven automatically for several days, and an initial inspection is performed periodically, then in the event of the aforementioned abnormalities occurring inside the vehicle, concerns can be effectively suppressed that the left and right brakes 42 may not function properly as safety brakes.

[0196] Furthermore, the safety braking function unit 22Fa can also be configured such that, during the determination process, if the driving mode is already in automatic driving mode after the effective period of the initial inspection completion state has elapsed, the initial inspection completion state is made valid while the user keeps the automatic driving mode running, and the initial inspection completion state is made invalid when the user ends the automatic driving mode, thereby changing from the initial inspection completion state to the initial state.

[0197] On the other hand, if the driving mode is manual driving mode, the safety braking function unit 22Fa will notify the LCD monitor 32 or the like that the validity period of the initial inspection completion state has expired.

[0198] Therefore, when the tractor 1 is driven manually by the passenger, the passenger can be notified in advance that an initial check is required when switching the driving mode to automatic driving mode. In addition, even during manual driving without the left and right brakes 42 being activated as safety brakes, the reduction in work efficiency caused by periodic initial checks can be prevented.

[0199] If the aforementioned abnormalities occur inside the vehicle after the initial inspection is completed, the safety braking function unit 22Fa switches to the safety braking operation state. Figure 24As shown in the Brake_Move diagram, the steering control unit 22C is instructed to perform braking operations on the left and right brakes 42 based on the movement of the electric motor 102. Thus, the steering control unit 22C performs braking operations on the left and right brakes 42 based on the movement of the electric motor 102.

[0200] When the safety braking function unit 22Fa is in the state of initial inspection completed, if the release switch 113 detects that the connecting pin 112 has reached the release position and the brake switch 114 detects that the connecting pin 112 has reached the braking position, it determines that any one of the electric motor 102, the release switch 113 and the brake switch 114 has malfunctioned, and thus switches to the above-mentioned error detection state.

[0201] When the safety braking function unit 22Fa is in the initial inspection completed state, and during the effective period of the initial inspection completed state, and without any of the aforementioned abnormalities occurring inside the vehicle, if the release switch 113 does not detect the arrival of the connecting pin 112 to the release position, it switches to the aforementioned inspection completed brake release recovery operation state. Figure 24 As shown in OK_Rev), the steering control unit 22C is instructed to release the left and right brakes 42 based on the operation of the electric motor 102. Thus, the steering control unit 22C performs the release operation of the left and right brakes 42 based on the operation of the electric motor 102.

[0202] If, after checking the brake release and recovery operation state, the safety braking function unit 22Fa fails to detect the arrival of the connecting pin 112 to the release position by the release switch 113 even after the specified time for brake release operation has elapsed, it determines that any one of the electric motor 102, the release switch 113, and the brake switch 114 has malfunctioned, and thus switches to the aforementioned error detection state.

[0203] When the safety braking function unit 22Fa has completed the brake release and recovery operation, if the release switch 113 detects that the connecting pin 112 has reached the release position within the specified time for the brake release operation, it will switch to the initial inspection completion state. Figure 24 The Check_OK shown indicates that the display screen of the LCD monitor 32 is switched to [the specified value]. Figure 22 The automatic driving start screen 32D shown allows for the switching of driving modes from manual driving mode to automatic driving mode.

[0204] Safety braking function unit 22Fa in the above-mentioned brake release recovery operation state ( Figure 24In the Rev_Start shown, if the release switch 113 detects that the connecting pin 112 has reached the release position and the brake switch 114 detects that the connecting pin 112 has reached the brake position, or if the release switch 113 does not detect that the connecting pin 112 has reached the release position even after the specified time for brake release operation, it is determined that any one of the electric motor 102, the release switch 113, and the brake switch 114 has malfunctioned, and thus the system switches to the above-mentioned error detection state.

[0205] In the brake release recovery operation state, if the safety braking function unit 22Fa detects that the release switch 113 has reached the release position of the connecting pin 112, and the brake switch 114 has not detected that the connecting pin 112 has reached the braking position, it switches back to the initial state described above. Figure 24 (As shown in the Start).

[0206] Safety braking function unit 22Fa in the above-mentioned safety braking operation state ( Figure 24 In the Brake_Move shown, if the release switch 113 still detects the arrival of the connecting pin 112 to the release position even after the specified time for braking operation has elapsed, or if the brake switch 114 does not detect the arrival of the connecting pin 112 to the braking position, it is determined that any one of the electric motor 102, release switch 113, and brake switch 114 has malfunctioned, and thus the above-mentioned error detection state is switched to.

[0207] In the safety braking operation state, if the release switch 113 does not detect the connection pin 112 reaching the release position, but the brake switch 114 detects the connection pin 112 reaching the braking position, and a predetermined braking operation time has elapsed, the safety braking function unit 22Fa determines that the left and right brake pedals 40 have been operated to the maximum depressed position, and the left and right brakes 42 are switched to the braking state. Furthermore, based on this determination, it switches to the safety braking operation holding state. Figure 24 The steering control unit 22C is instructed to stop the braking operation of the left and right brakes 42 based on the operation of the electric motor 102, as shown in the Brake_Stop instruction. Thus, the steering control unit 22C terminates the braking operation of the left and right brakes 42 based on the operation of the electric motor 102. As a result, the tractor 1 can be kept in a stopped state by maintaining the left and right brakes 42 as safety brakes.

[0208] like Figure 25 As shown, in the error detection state, the safety braking function unit 22Fa switches to an abnormal electric motor state based on the detection states of the release switch 113 and the brake switch 114. Figure 25The Err_Actuater shown indicates that the detection of abnormal states is enabled. Figure 25 The Err_Position_ON indicator and the disabled abnormal detection state are shown. Figure 25 Any of the following (Err_Position_Off). Furthermore, in any abnormal state, if it is not a transition from the safety braking operation state, it transitions to the abnormal braking release state (as shown). Figure 25 The system displays Err_Rev and instructs the steering control unit 22C to release the left and right brakes 42 based on the operation of the electric motor 102. As a result, the steering control unit 22C releases the left and right brakes 42 based on the operation of the electric motor 102. Furthermore, this release operation allows the left and right brakes 42 to return to the released state, enabling manual driving of the tractor 1 based on the passenger's driving.

[0209] If the safety braking function unit 22Fa is in an abnormal braking release state, and a predetermined time for the release operation has elapsed, it will switch to an abnormal state. Figure 25 The Err_Actuater shown in the figure continues in this state.

[0210] If the safety braking function unit 22Fa is in any of the following states—electric motor abnormality, open detection abnormality, and closed detection abnormality—and is transitioning from the safety braking operation state, it will switch to the aforementioned abnormal state. Figure 25 The Err_Actuater shown is maintained in this state. Thus, even in this abnormal state, the left and right brakes 42 can be activated as safety brakes, and the tractor 1 can be kept in a braking and stopped state.

[0211] [Other Implementation Methods]

[0212] Other embodiments of the present invention will be described.

[0213] Furthermore, the structures of the embodiments described below are not limited to being applied individually, but can also be applied in combination with the structures of other embodiments.

[0214] (1) Other representative implementations related to the structure of the work vehicle are described below.

[0215] For example, the work vehicle may also be configured as a half-track with the following configuration: as a running gear 10, 11, it has left and right front wheels 10 and left and right tracks instead of left and right rear wheels 11.

[0216] For example, the work vehicle may also be configured as a fully tracked vehicle with left and right tracks replacing the left and right front wheels 10 and the left and right rear wheels 11 as the running gear 10 and 11.

[0217] For example, the work vehicle can also be configured as an electric vehicle equipped with an electric motor instead of engine 14.

[0218] For example, the work vehicle can also be configured as a hybrid powertrain with an engine 14 and an electric motor.

[0219] For example, the work vehicle may also be configured to have a protective frame extending upward from the tractor 1 instead of the cab 13.

[0220] (2) Other representative embodiments related to the electric actuator 102 are described below.

[0221] For example, as an electric actuator 102, it may also include left and right electric motors 102 that operate the left and right brake pedals 40 independently.

[0222] For example, the electric actuator 102 may also include a single electric cylinder that operates the left and right brake pedals 40 connected by the connecting mechanism 55.

[0223] For example, the electric actuator 102 may also include left and right electric cylinders that can independently operate the left and right brake pedals 40.

[0224] (3) The foot brake 42 may also be a single component operated by a single brake pedal provided in the driver's unit 12.

[0225] Industrial availability

[0226] This invention can be applied, for example, to working vehicles such as tractors, passenger lawnmowers, passenger rice transplanters, combine harvesters, transport vehicles, wheel loaders, and snowplows.

[0227] Explanation of reference numerals in the attached figures

[0228] 2...Automatic driving unit; 10...Driving device (front wheel); 11...Driving device (rear wheel); 22Fa...Control unit (safety braking function unit); 32a...Mode selection unit; 42...Foot brake (brake); 102...Electric actuator (electric motor); 113...First motion sensor (release switch); 114...Second motion sensor (brake switch).

Claims

1. A working vehicle, wherein, have: Foot brake, which brakes the driving device; An automatic driving unit that enables the vehicle to drive automatically; The mode selection unit is capable of selecting an automatic driving mode in which the vehicle drives automatically via the automatic driving unit. as well as An electric actuator switches the foot brake to a braking state that applies braking to the travel device and a released braking state. The automatic driving unit has a control unit that controls the operation of the electric actuator. The control unit is configured to perform an action confirmation process when the automatic driving mode is selected by the manual operation of the mode selection unit, confirming whether the foot brake is operating normally under the action control of the electric actuator. If the normal operation of the foot brake is confirmed in the action confirmation process, the control unit switches to the action confirmation completion state, allowing the driving mode to switch from the manual driving mode to the automatic driving mode.

2. The operating vehicle according to claim 1, wherein, have: A first motion sensor detects the motion of the electric actuator; and The second motion sensor detects the action of the foot brake. The action confirmation process includes: a first action confirmation process, which confirms whether the electric actuator is operating normally based on detection information from the first action sensor; and a second action confirmation process, which confirms whether the foot brake is operating normally based on detection information from the second action sensor.

3. The operating vehicle according to claim 1 or 2, wherein, When the control unit is about to perform the action confirmation process, it performs a pre-condition determination process to determine whether the conditions for starting the action confirmation process are met. If the pre-condition determination process determines that the conditions for starting the action confirmation process are met, the action confirmation process is performed.

4. The operating vehicle according to any one of claims 1 to 3, wherein, When the control unit switches to the action confirmation completion state, it performs a validity period determination process to determine whether the validity period of the action confirmation completion state has elapsed. If the validity period of the action confirmation completion state has elapsed in the automatic driving mode, the driving mode is switched from the automatic driving mode to the manual driving mode and the action confirmation completion state is switched back to the initial state. If the normal operation of the foot brake is confirmed again through the action confirmation process, the control unit switches back to the action confirmation completion state and allows the switch to the automatic driving mode.

5. The operating vehicle according to any one of claims 1 to 4, wherein, When the control unit switches to the state where the action confirmation is completed, it performs a validity period determination process to determine whether the validity period of the action confirmation is completed has elapsed. If the validity period of the action confirmation is completed has elapsed in the manual driving mode, it reports that the validity period has elapsed.

Images