Work vehicle and control device

Abstract

To provide a work vehicle and a control device that do not require steering a steering member from a left steering angle limit position to a right steering angle limit position.SOLUTION: A combine 1 being a work vehicle includes a traveling device 102, a first shaft 503, a motor 505, and a control unit 50. The first shaft 503 controls a traveling direction of the traveling device 102. The motor 505 drives the first shaft 503. The control unit 50 sets a reference rotation position P2 of the motor 505 on the basis of a rotation amount V that is smaller than a maximum rotation amount VA of the first shaft 503 from a rotational reference position P1 of the first shaft 503.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a work vehicle and a control device. [Background technology]

[0002] Patent Document 1 discloses a vehicle equipped with a motor that drives a steering member, three resolver sensors, and a steering angle detection device that detects the absolute angle of the steering member. After the vehicle is steered from the left steering angle limit position to the right steering angle limit position, the absolute angle and neutral position of the steering member are calculated using the relative angle differences of the three resolver sensors. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-333657 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, in order to calculate the neutral position of the steering member that serves as a reference for straight-ahead driving, it is necessary to steer the steering member from the left steering angle limit position to the right steering angle limit position.

[0005] The present invention has been made in view of the above-mentioned problems, and its object is to provide a work vehicle and a control device that do not require steering of the steering member from the left steering angle limit position to the right steering angle limit position. [Means for solving the problem]

[0006] According to a first aspect of the present invention, a work vehicle includes a travel unit, a shaft, a motor, and a control unit. The shaft controls the traveling direction of the travel unit. The motor drives the shaft. The control unit sets a reference rotation position of the motor based on an amount of rotation of the shaft that is smaller than the maximum amount of rotation of the shaft from a rotation reference position of the shaft.

[0007] According to a second aspect of the present invention, a control device is mounted on a work vehicle including a traveling unit, a shaft, a motor, and a detection unit. The control device includes an acquisition unit and a setting unit. The shaft controls the traveling direction of the traveling unit. The motor drives the shaft. The detection unit detects the amount of rotation of the shaft that controls the traveling direction of the traveling unit. The acquisition unit acquires the amount of rotation of the shaft from the detection unit. The setting unit sets a reference rotation position of the motor based on an amount of rotation that is smaller than the maximum amount of rotation of the shaft from a rotation reference position of the shaft. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a work vehicle and a control device that do not require steering of the steering member from the left steering angle limit position to the right steering angle limit position. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of a crop harvesting system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram of the combine harvester according to the present embodiment. [Figure 3] FIG. 2 is a side view showing the inside of the steering column of the combine harvester according to the present embodiment. [Figure 4] FIG. 2 is a perspective view showing the upper interior of the steering column. [Figure 5] FIG. 4 is a plan view showing the sector gear and the detent lever when traveling straight. [Figure 6] FIG. 4 is a plan view showing the sector gear and the detent lever during turning. [Figure 7] 10A and 10B are diagrams illustrating the operation of a straight-line detection sensor. [Figure 8] 4 is a flowchart showing an operation mode control according to the present embodiment. [Figure 9] 6 is a flowchart showing a reference rotation position setting control according to the present embodiment. [Figure 10]10 is a flowchart showing an operation mode control according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and description thereof will not be repeated.

[0011] A crop harvesting system 100 according to this embodiment will be described with reference to Figures 1 to 3. Figure 1 is a schematic diagram of the crop harvesting system 100 according to this embodiment. Figure 2 is a block diagram of a combine harvester 1 according to this embodiment. Figure 3 is a side view showing the inside of a steering column 502 of the combine harvester 1 according to this embodiment.

[0012] In this specification, for ease of understanding, the terms "front-rear direction," "left-right direction," and "up-down direction" may be used. Here, the terms "front-rear direction," "left-right direction," and "up-down direction" are directions as seen from the perspective of an operator (i.e., a driver) seated in a driver's seat (not shown) located in the driving space 2a (see FIG. 1). However, the terms "front-rear direction," "left-right direction," and "up-down direction" are defined merely for the sake of convenience, and are not intended to limit the orientation of the combine harvester 1 of the present invention during use.

[0013] The crop harvesting system 100 includes a head-feeding combine harvester 1, which is a work vehicle, and a mobile communication terminal 7. The crop harvesting system 100 is an example of an automatic driving system in which an operator gives instructions using the mobile communication terminal 7 or the like to the combine harvester 1, causing the combine harvester 1 to automatically drive while performing work such as harvesting crops. Note that instructions for automatic driving may be given by operating an operating member provided on the combine harvester 1, rather than the mobile communication terminal 7. Note that the combine harvester 1 can be manually driven by the operator when instructions for automatic driving are not given.

[0014] Autonomous operation means that the control unit 50 provided in the combine harvester 1 controls the devices related to travel, and at least the steering of the combine harvester 1 is performed autonomously so that the combine harvester 1 follows a predetermined route. In addition to steering, the vehicle speed or work performed by the work devices may also be performed autonomously. Autonomous operation includes both cases where a person is on the combine harvester 1 and cases where a person is not on the combine harvester 1.

[0015] As shown in FIG. 1, the combine harvester 1 of this embodiment includes a traveling body 101, a traveling device 102, a reaping device 200, a threshing device 300, a grain tank 400, a control unit 50, a memory unit 55, a communication device 16, a steering mechanism 500 (see FIG. 3), and a transmission mechanism 600 (see FIG. 3). The traveling device 102 is disposed below the traveling body 101 and supports the traveling body 101. The reaping device 200 is disposed in front of the traveling body 101. The reaping device 200 and the threshing device 300 are examples of work devices. The communication device 16 is disposed above the traveling body 101. The control unit 50 is disposed inside the traveling body 101. The memory unit 55 is disposed inside the traveling body 101. The traveling device 102 corresponds to, for example, a "traveling unit."

[0016] The traveling machine body 101 (combine 1) includes an engine (not shown). The engine is, for example, a diesel engine. The engine converts thermal energy obtained by burning fuel into kinetic energy (power).

[0017] The traveling device 102 causes the combine harvester 1 to travel. Specifically, the traveling device 102 travels based on power (kinetic energy) generated in the engine. The traveling device 102 includes, for example, a pair of left and right traveling crawler devices. The pair of left and right traveling crawler devices causes the combine harvester 1 to travel in the front-to-rear direction. In addition, the pair of left and right traveling crawler devices causes the combine harvester 1 to turn in the left and right direction.

[0018] The reaping device 200 is driven by power (kinetic energy) generated by an engine. The reaping device 200 reaps uncut stalks in a field. In this embodiment, the reaping device 200 includes a reaping frame 201 and a stalk transport device 204.

[0019] The reaping frame 201 is mounted to the front of the traveling body 101 so as to be able to move up and down freely. A reaping blade is disposed below the reaping frame 201. The reaping device 200 moves the reaping blade back and forth to cut the base of uncut stalks in the field.

[0020] The stalk conveying device 204 conveys the stalks cut by the cutting blade to the threshing device 300.

[0021] The combine harvester 1 can drive the traveling device 102 to move within the field, and drive the reaping device 200 to continuously reap unharvested stalks in the field.

[0022] The threshing device 300 is driven by power (kinetic energy) generated by the engine. The threshing device 300 performs threshing work by threshing the reaped stalks transported to the traveling body 101 by the stalk transport device 204. Threshing work is included in the harvesting work. The grain tank 400 stores the grains threshed by the threshing device 300. Specifically, the threshing device 300 is equipped with a winnowing fan 303 and a dust discharge fan 305. The threshing device 300 threshes the tip side of the reaped stalks transported to the traveling body 101. The threshing device 300 shakes and sorts (gravity sorts) the threshed tip side (degrained grain).

[0023] The winnowing fan 303 supplies screening air toward the reaped stalks after threshing. As a result, straw dust and impurities are removed from the grain (threshed grain). The grain from which straw dust and impurities have been removed is transported to and stored in the grain tank 400. The dust discharge fan 305 discharges the dust at the rear of the threshing device 300 outside the machine.

[0024] The traveling machine body 101 (combine 1) further includes a cabin 2. The cabin 2 is box-shaped, and inside the cabin 2, an operating space 2a is formed where an operator sits in the operator's seat and operates the combine 1. Side columns (not shown) are arranged in the operating space 2a.

[0025] For example, a main speed change lever and the like are disposed on the side column. The main speed change lever is disposed to the left of the driver's seat. The main speed change lever is operated by an operator seated in the driver's seat to switch the traveling direction of the traveling device 102 shown in FIG. 1 between forward and reverse. A transmission (not shown) is disposed below the side column.

[0026] The main speed change lever has various switches, including, for example, a switch for adjusting the threshing depth, a switch for raising the reaping device 200, a switch for lowering the reaping device 200, a switch for adjusting the height of the reaping device 200, and a switch for switching whether or not power generated by the engine is transmitted to the reaping device 200 and the threshing device 300. The steering wheel, main speed change lever, and various switches output signals to the control unit 50 indicating instructions according to operations by the operator.

[0027] The communication device 16 includes a positioning antenna 61 , an inertial measurement unit 62 , and a communication antenna 63 .

[0028] The positioning antenna 61 receives radio waves (positioning signals) from positioning satellites that make up the Global Navigation Satellite System (GNSS). The inertial measurement unit 62 includes a three-axis angular velocity sensor and a three-directional acceleration sensor.

[0029] The communication antenna 63 is an antenna for wireless communication with the mobile communication terminal 7. For wireless communication, a wireless LAN (Local Area Network) such as Wi-Fi (registered trademark) or a short-range wireless communication such as Bluetooth (registered trademark) is adopted. The combine harvester 1 may also be provided with a mobile communication antenna (not shown) for communication using a mobile phone line and the Internet.

[0030] 2, the control unit 50 controls the traveling device 102, the reaping device 200, and the threshing device 300. Specifically, the control unit 50 includes a processor such as a CPU (Central Processing Unit) and an MPU (Micro Processing Unit).

[0031] The control unit 50 receives signals output from the steering wheel 501 (see FIG. 1), the main speed change lever, various switches, etc., and controls the traveling device 102, the reaping device 200, and the threshing device 300 according to the instructions indicated by the signals. The control unit 50 may be a single piece of hardware, or may be multiple pieces of hardware that can communicate with each other.

[0032] The storage unit 55 is a main storage device such as a read-only memory (ROM) and a random access memory (RAM). The storage unit 55 may further include an auxiliary storage device such as a hard disk drive (HDD) or a solid state drive (SSD). The storage unit 55 stores various programs, data, and the like. The control unit 50 reads out and executes the various programs from the storage unit 55.

[0033] In addition to the inertial measurement device 62, the control unit 50 is connected to a display unit 53, an alarm unit 56, an operation unit 57, a reception unit 58, a power supply 59, a position acquisition unit 64, a communication processing unit 65, a vehicle speed sensor 66, a rotation angle sensor 67, a cutting sensor 68, a harvest yield sensor 69, and a straight-line detection sensor 551.

[0034] Display unit 53 displays information related to operation to the operator. Specifically, display unit 53 is a screen such as a liquid crystal display or an organic EL (Electroluminescence) display.

[0035] The notification unit 56 notifies the operator of information related to operation. Specifically, the notification unit 56 is a lamp or a display. The notification unit 56 notifies, for example, whether the autonomous driving mode can be executed or whether it is necessary to obtain information required to execute the autonomous driving mode. The notification unit 56 may also issue a warning. The notification unit 56 may also be provided within the display unit 53.

[0036] The operation unit 57 accepts an operation to start or stop the combine harvester 1. In other words, the operation unit 57 accepts an operation to supply power to the motor 505 and an operation to cut off power to the motor 505. The operation unit 57 starts the combine harvester 1 by an ON operation. The operation unit 57 stops the combine harvester 1 by an OFF operation. Specifically, the operation unit 57 is a start button or an ignition switch. Hereinafter, starting the combine harvester 1 by turning the operation unit 57 ON may be referred to as turning on the power.

[0037] The reception unit 58 receives an instruction to execute the autonomous driving mode. Specifically, the reception unit 58 is an operation switch disposed in the driving space 2a (see FIG. 1). Note that the reception unit 58 is not limited to a manual switch, and may be a pedal operated by the foot.

[0038] The power supply 59 generates the power to be supplied to each electrical device and the motor 505. Specifically, the power supply 59 is a battery.

[0039] The position acquisition unit 64 acquires the position of the combine harvester 1 as, for example, latitude and longitude information using a positioning signal received by the positioning antenna 61 from a positioning satellite. The position acquisition unit 64 may receive a positioning signal from a reference station (not shown) using an appropriate method and then perform positioning using a known RTK-GNSS (Real Time Kinematic GNSS) method. The reference station is installed at a known position around the field. Alternatively, the position acquisition unit 64 may perform positioning using a DGNSS (Differential GNSS) method. Alternatively, the position acquisition unit 64 may perform position acquisition based on the radio wave intensity of a wireless LAN or the like, or by inertial navigation using the measurement results of the inertial measurement unit 62.

[0040] The communication processing unit 65 transmits and receives data to and from the mobile communication terminal 7 via the communication antenna 63 .

[0041] The vehicle speed sensor 66 detects the vehicle speed of the combine 1. The vehicle speed sensor 66 is provided on an axle or the like disposed on the traveling device 102. When the vehicle speed sensor 66 is provided on the axle of the traveling device 102, the vehicle speed sensor 66 generates a pulse corresponding to the rotation of the axle. Data of the detection result obtained by the vehicle speed sensor 66 is output to the control unit 50.

[0042] The rotation angle sensor 67 is an angular displacement sensor that detects the amount of rotation of the first shaft 503 using electromagnetic induction. The rotation angle sensor 67 measures the electromotive force when the relative position of a rotor (not shown) and a stator (not shown) of the motor 505 provided on the handle 501 changes. The rotation angle sensor 67 detects the rotation angle of the motor 505 based on the measured electromotive force. The rotation angle sensor 67 detects the amount of rotation of the first shaft 503 (see FIG. 3 ) that controls the traveling direction of the traveling device 102. Data of the detection result obtained by the rotation angle sensor 67 is output to the control unit 50. The rotation angle sensor 67 corresponds to, for example, a "detection unit." The rotation angle sensor 67 is, for example, a resolver.

[0043] The reaping sensor 68 detects the height of the reaping device 200 and the operating state of the reaping device 200. The detection result data obtained by the reaping sensor 68 is output to the control unit 50. Based on the detection result of the reaping sensor 68, the control unit 50 can determine whether the reaping device 200 is performing reaping work. The reaping work is included in the harvesting work.

[0044] The harvest yield sensor 69 detects the amount of grain harvested by the combine 1. The harvest yield sensor 69 outputs information indicating the detected amount of grain to the control unit 50. For example, the harvest yield sensor 69 is provided in the grain tank 400. The harvest yield sensor 69 measures the degree of impact when the grain collides with the harvest yield sensor 69 as the grain is transported to the grain tank 400, and outputs the measurement result to the control unit 50. The control unit 50 acquires the measurement result of the harvest yield sensor 69, converts it into the weight or volume of the grain, and generates harvest yield information indicating the amount of grain harvested by the combine 1. The control unit 50 does not need to convert the measurement result of the harvest yield sensor 69. In this case, the harvest yield information indicates the measurement result of the harvest yield sensor 69. Note that the harvest yield sensor 69 is not an essential component of the crop harvesting system 100.

[0045] The straight-line movement detection sensor 551 is, for example, a microswitch-type straight-line movement sensor. The straight-line movement detection sensor 551 is provided as part of the components of the steering mechanism 500 (see FIG. 3). The straight-line movement detection sensor 551 is supported by a support part 509 (see FIG. 4) fixed to the steering column 502.

[0046] In this embodiment, the control unit 50 is capable of controlling the automatic operation of the combine harvester 1, such as vehicle speed control and steering control. Specifically, under the control of the control unit 50, the combine harvester 1 can autonomously move forward, backward, turn, and the like. Furthermore, the control unit 50 can, for example, autonomously perform steering and also control the vehicle speed to change in response to the operator's operation.

[0047] When autonomously changing the vehicle speed, the control unit 50 controls the current vehicle speed detected by the vehicle speed sensor 66 to approach the target vehicle speed. The vehicle speed control is realized, for example, by changing at least one of the gear ratio of a transmission (not shown) in a transmission case (not shown) or the engine rotation speed. Note that the vehicle speed control also includes control to reduce the vehicle speed to zero so that the combine harvester 1 stops.

[0048] When steering autonomously, the control unit 50 controls the current steering angle detected by the rotation angle sensor 67 to approach the target steering angle. The steering angle control is realized, for example, by driving a motor 505 connected to a first shaft 503 (see FIG. 3) of the steering wheel 501 via multiple gears. Note that the control unit 50 may adjust the turning angle of the traveling device 102 by adjusting the rotation of each of the left and right traveling crawler devices of the traveling device 102.

[0049] Furthermore, the control unit 50 controls the operation of the reaping device 200 and the threshing device 300 based on predetermined conditions. Specifically, the control unit 50 controls the height adjustment and reaping work of the reaping device 200, as well as the threshing work by the threshing device 300.

[0050] Based on the detection results of the various sensors, the control unit 50 controls automatic operation, controls the operation of the reaping device 200 and the threshing device 300, and determines whether to continue harvesting. In addition to the above controls, the control unit 50 can also control the running of the combine 1 in response to remote operation by the operator using the mobile communication terminal 7, controls the operation of the reaping device 200 and the threshing device 300, and determines whether to continue harvesting.

[0051] The mobile communication terminal 7 is a tablet terminal, a smartphone, a laptop computer, or the like. The mobile communication terminal 7 performs various processes related to the automatic operation of the combine harvester 1, as described below, but at least some of these processes can also be performed by the control unit 50 of the combine harvester 1. Conversely, at least some of the various processes related to the automatic operation performed by the control unit 50 of the combine harvester 1 can also be performed by the mobile communication terminal 7.

[0052] Next, the steering mechanism 500 and the transmission mechanism 600 will be described with reference to Figures 3 to 7. Figure 4 is a perspective view showing the interior of the upper side of the steering column 502. Figure 5 is a plan view showing the sector gear 534 and the detent lever 84 when traveling straight. Figure 6 is a plan view showing the sector gear 534 and the detent lever 84 when turning. Figure 7 is a diagram explaining the operation of the straight traveling detection sensor 551.

[0053] 1 and 3 to 6, steering mechanism 500 has a steering wheel (hereinafter sometimes referred to as a handle) 501, a steering column 502, a first shaft 503, a second shaft 504, a motor 505, a steering input shaft 511, a steering input member 512, a steering input coupling 513, a steering output shaft 521, a steering output member 522, a steering output coupling 523, and a steering coupling member 530. Transmission mechanism 600 has a main transmission shaft 614, a transmission input shaft 611, a transmission input member 612, a transmission input coupling 613, a transmission output shaft 621, a transmission output member 622, a transmission output coupling 623, a transmission coupling member 630, and a main transmission member 640.

[0054] The handle 501 is connected to the upper end of the first shaft 503 at the top of the steering column 502. The handle 501 is, for example, a round steering handle. However, the handle 501 is not limited to a round handle. The handle 501 may also be a lever-shaped operating part.

[0055] The first shaft 503 is rotatably supported by a shaft case formed on the upper part of the steering column 502. The first shaft 503 extends in the vertical direction. The first shaft 503 controls the traveling direction of the traveling device 102. A second shaft 504 is connected to the lower end of the first shaft 503 via a universal joint 506. The second shaft 504 is rotatably supported by the upper part of the steering column 502. The second shaft 504 has a gear 533 at its lower part.

[0056] The steering mechanism 500 further includes a sector gear 534, a steering operation shaft 541, and a straight-line detection sensor 551. The second shaft 504 is connected to the steering input shaft 511 via the gear 533 and the sector gear 534.

[0057] The transmission input shaft 611 is cantilevered and supported by a bearing (not shown) so as to extend in the left-right direction. The transmission input shaft 611 is rotatably supported by the bearing. The transmission input member 612 is disposed between the upper surface of the transmission input shaft 611 and the lower surface of the steering input member 512.

[0058] When steering input shaft 511 is rotated forward or backward, it rotates steering input member 512 and transmission input shaft 611 forward or backward around the substantially vertical axis of steering input shaft 511 against the force of a spring (not shown). A universal joint (not shown) is disposed at the intersection where the axis of steering input shaft 511 and the axis of transmission input shaft 611 intersect at a right angle.

[0059] As the transmission input shaft 611 rotates forward or backward, the steering input member 512 and the transmission input shaft 611 tilt in the front-to-rear direction around the axis of the transmission input shaft 611. As the steering input shaft 511 rotates forward or backward, the steering input member 512 and the transmission input shaft 611 rotate forward or backward around the axis of the steering input shaft 511. The main transmission member 640 connects the transmission input shaft 611 and the main transmission shaft 614.

[0060] An upper end of the steering coupling member 530 is coupled to the steering input member 512 via a steering input coupling portion 513. A lower end of the steering coupling member 530 is coupled to the steering output member 522 via a steering output coupling portion 523.

[0061] An upper end of the transmission coupling member 630 is connected to a transmission input member 612 via a transmission input connector 613. A lower end of the transmission coupling member 630 is connected to a transmission output member 622 via a transmission output connector 623. The steering output member 522 and the transmission output member 622 are connected to the transmission via a rod (not shown).

[0062] As described above, the steering mechanism 500 forms a conical steering link. In a conical steering link, the end points of the straight-line rod and the turning rod are located at the base circle of the cone with a phase difference of 90 degrees. The other end points of both rods are located at the apexes of two cones, one large and one small. In addition, this embodiment employs, for example, a forced differential type differential mechanism. A forced differential type employs planetary gears on the left and right sides of the differential device, forcibly rotating the differential in the opposite direction and creating a speed difference between the left and right crawlers to cause turning. The forced differential type is an HST mechanism (hydraulic transmission) that applies forced power.

[0063] In the automatic driving mode, the motor 505 drives the first shaft 503. The drive shaft of the motor 505 is connected to the first shaft 503 via a reduction gear 507 and a reduction gear 508. The control unit 50 controls the traveling direction of the traveling device 102 (see FIG. 1) by driving the motor 505.

[0064] As shown in FIGS. 5 and 6, gear 533 connected to second shaft 504 meshes with sector gear 534 connected to steering input shaft 511 (see FIG. 3). When handle 501 is rotated to one side at its maximum, stopper 533a of gear 533 abuts against stopper 534a of sector gear 534. When handle 501 is rotated to the other side at its maximum, stopper 533b of gear 533 abuts against stopper 534b of sector gear 534. This physically limits rotation of handle 501 beyond the maximum rotation amount VA corresponding to the maximum rotation of handle 501. Sector gear 534 has a plurality of teeth 534t and an arc cam 534c.

[0065] The arc cam 534c has a notch 534n at its circumferential center. In this embodiment, when the notch 534n is located on the longitudinal axis passing through the center of the steering input shaft 511, the combine harvester 1 travels straight ahead. In other words, when the notch 534n is located on the longitudinal axis passing through the center of the steering input shaft 511, the handle 501 is located in a neutral position N. The neutral position N is the rotational position of the handle 501 at which the combine harvester 1 travels straight ahead.

[0066] The steering mechanism 500 further includes a detent unit 80. The detent unit 80 includes a detent arm 81, a detent roller 82, a detent shaft 83, and a detent lever 84.

[0067] The detent arm 81 is rotatably supported by the steering column 502. Specifically, one end of a detent shaft 83 is rotatably supported by the steering column 502 (see FIG. 3), and the detent arm 81 is fixed to the other end of the detent shaft 83. The detent arm 81 has the detent shaft 83 fixed to a base end in the longitudinal direction, and a detent roller 82 rotatably supported at a tip end in the longitudinal direction. One end of a neutral spring is engaged with the detent lever 84, and the other end of the neutral spring abuts against a receiving plate (not shown) of the steering column 502 (see FIG. 3). This allows the detent roller 82 to elastically abut against the arc cam 534c and the notch 534n.

[0068] As shown in FIGS. 5 to 7, a straight-line detection sensor 551 is disposed on the detent lever 84. The straight-line detection sensor 551 detects the rotational position of the handle 501 relative to the traveling machine body 101 when the combine harvester 1 travels straight. The straight-line detection sensor 551 has a contact point 552 and a terminal 553. The straight-line detection sensor 551 detects a rotation reference position P1 of the first shaft 503 (see FIG. 3). Specifically, the straight-line detection sensor 551 detects a range from the neutral position N to 11 degrees of left steering and a range from the neutral position N to 11 degrees of right steering. When the stopper 533a (533b) of the gear 533 abuts against the stopper 534a (534b) of the sector gear 534, the handle 501 is operated corresponding to the maximum rotation amount VA. Therefore, since the straight-line detection sensor 551 detects a rotation reference position P1 that is smaller than the maximum rotation amount VA, unnecessary turning operations can be suppressed. Hereinafter, the left rotation reference position may be referred to as rotation reference position P1L, and the right rotation reference position may be referred to as rotation reference position P1R.

[0069] The straight-line movement detection sensor 551 outputs a detection signal in response to the rotational position of the first shaft 503 being at a first rotational position (rotational reference position P1L) on the left side or a second rotational position (rotational reference position P1R) on the right side with respect to the rotational reference position P1 corresponding to the first shaft 503. The rotational reference position P1 is the neutral position N of the first shaft 503 corresponding to the straight-line movement direction of the traveling device 102.

[0070] When the detent roller 82 abuts against the notch 534n, the contact 552 and the terminal 553 abut against each other. The abutment state between the contact 552 and the terminal 553 continues until the steering wheel 501 is steered 11 degrees left from the neutral position N of the first shaft 503, or until the steering wheel 501 is steered 11 degrees right from the neutral position N of the first shaft 503. When the steering wheel 501 is steered left or right beyond 11 degrees, the contact 552 and the terminal 553 are separated and become out of contact. As a result, the control unit 50 detects straight-line traveling of the traveling device 102 (see FIG. 1) when the straight-line traveling detection sensor 551 is in an on state, and detects a turning of the traveling device 102 (see FIG. 1) when the straight-line traveling detection sensor 551 is in an off state.

[0071] Next, the control unit 50 will be further described. As shown in Fig. 2, the control unit 50 has an acquisition unit 51 and a setting unit 52. The processor of the control unit 50 executes a computer program stored in the storage unit 55 to function as the acquisition unit 51 and the setting unit 52.

[0072] The acquisition unit 51 acquires the rotation amount V of the first shaft 503 from the signal detected by the rotation angle sensor 67 .

[0073] As shown in FIGS. 1 to 3 and 7 , the setting unit 52 sets a reference rotational position P2 of the motor 505. The reference rotational position P2 is a reference rotational position of the motor 505 that defines the traveling direction of the traveling device 102. Because the rotation angle sensor 67 defines the reference position (0 degrees) at the time when power is supplied to the motor 505, the reference rotational position P2, which is the measurement reference position of the motor 505, is not associated with the rotational reference position P1, which is the measurement reference position of the first shaft 503. However, the current position of the motor 505 can be defined by the rotational position of the first shaft 503. Therefore, the setting unit 52 sets the reference rotational position P2 of the motor 505 based on a rotation amount V that is smaller than the maximum rotation amount VA of the first shaft 503 from the rotational reference position P1 of the first shaft 503. This eliminates the need to steer the steering wheel 501 from the left steering angle limit position to the right steering angle limit position.

[0074] As shown in FIG. 7 , when power is supplied to the motor 505 when the first shaft 503 is at the rotation start position Pa, the rotation angle sensor 67 acquires the current rotation start position Pa as the operation start point of the motor 505. When the steering wheel 501 is operated and passes the rotation reference position P1R, the straight-line detection sensor 551 changes from the OFF region to the ON region. At this timing, the rotation amount V (V2) of the motor 505 at the rotation reference position P1R is determined. Since the rotation amount V of the motor 505 at the rotation reference position P1R is determined, the position rotated 11 degrees from this rotation position of the motor 505 is the neutral position N of the motor 505. This allows the reference rotation position P2 of the motor 505 to be set without operating the steering wheel 501 to the maximum. Therefore, unnecessary turning is not generated. Note that the reference rotation position P2 of the motor 505 is not limited to the neutral position N. The reference rotation position P2 of the motor 505 may be set to a position other than the neutral position N.

[0075] The setting unit 52 sets the reference rotation position P2 of the motor 505 based on the amount of rotation V2 when the motor 505 passes through the rotation reference position P1R from the rotation start position Pa and the amount of rotation V1 when the motor 505 passes through the rotation reference position P1L from the rotation start position Pa, thereby making it possible to determine the neutral position N with high accuracy. Specifically, the setting unit 52 measures the number of sine wave pulses detected from the timing when the rotation reference position P1R is detected to the timing when the rotation reference position P1L is detected, and sets the reference rotation position P2 based on the measured number of sine wave pulses. Furthermore, because the reference rotation position P2 is set based on the amount of left rotation V1 and the amount of right rotation V2, it is less susceptible to structural errors than when the reference rotation position P2 is set based on only the amount of rotation of one side.

[0076] The left rotation amount V1 and the right rotation amount V2 of the first shaft 503 are the same rotation amount. This makes it easy to determine the neutral position N. That is, the control unit 50 measures the number of sine wave pulses detected between the time when the rotation reference position P1R is detected and the time when the rotation reference position P1L is detected, and determines the position corresponding to the peak of the central sine wave pulse among the peaks of the measured sine wave pulses as the reference rotation position P2. Alternatively, the control unit 50 may add the detected left rotation amount V1 and the right rotation amount V2 together, and then halve the sum to determine the rotation amount V3. The determined rotation amount V3 can also be used to set the reference rotation position P2 of the motor 505.

[0077] The control unit 50 sets the reference rotation position P2 of the motor 505 based on the detection signal of the straight-line detection sensor 551. By using the straight-line detection sensor 551 that detects the straight-line position of the steering wheel 501, the configuration can be simplified. In other words, it is possible to avoid the need to use a dedicated steering angle sensor for setting the reference rotation position P2.

[0078] The control unit 50 sets the reference rotation position P2 of the motor 505 during the period from when the power supply 59 is turned on until an instruction to start execution of the automatic driving mode is given. As a result, the reference rotation position P2 of the motor 505 is known, and the automatic driving mode can be executed immediately after the instruction to start execution is given. Specifically, because the reference rotation position P2 is set before the instruction to start execution is given, it is possible to omit traveling for setting the reference rotation position P2 after the instruction to start execution is given.

[0079] The control unit 50 can execute the automatic driving mode with high accuracy by restricting execution of the automatic driving mode until the reference rotation position P2 of the motor 505 is set. If the reference rotation position P2 of the motor 505 is not set, the coordinates of the traveling device 102 and the coordinates of the motor 505 do not match, and therefore the traveling device 102 cannot be operated in the desired direction. Therefore, to avoid unnecessary traveling, the execution of the automatic driving mode is restricted until the reference rotation position P2 is set.

[0080] Next, the processing executed by the control unit 50 will be described with reference to the flowcharts of Fig. 8 and Fig. 9. Fig. 8 is a flowchart showing operation mode control according to this embodiment. Fig. 9 is a flowchart showing setting control of the reference rotation position P2 according to this embodiment. As shown in Fig. 8, a program stored in the storage device of the storage unit 55 (see Fig. 2) causes the processor of the control unit 50 to execute the processing from step S1 to step S6.

[0081] 8, in step S1, the control unit 50 reads various pieces of information, and then the process proceeds to step S2.

[0082] In step S2, the control unit 50 determines whether or not an instruction to start the autonomous driving mode has been issued. If the control unit 50 determines that an instruction to start the autonomous driving mode has not been issued (No in step S2), the process ends. If the control unit 50 determines that an instruction to start the autonomous driving mode has been issued (Yes in step S2), the process proceeds to step S3.

[0083] In step S3, the control unit 50 determines whether the reference rotation position P2 has been set. If the control unit 50 determines that the reference rotation position P2 has not been set (No in step S3), the process proceeds to step S5. If the control unit 50 determines that the reference rotation position P2 has been set (Yes in step S3), the process proceeds to step S4.

[0084] In step S4, the control unit 50 executes the automatic operation mode. For example, a map image showing the surroundings of the farm field is displayed on the display unit 53. The combine harvester 1 travels along a preset route and performs work. The process then ends.

[0085] If the result of step S3 is No, in step S5, the control unit 50 controls the notification unit 56 to notify the user that the reference rotation position P2 has not been set. The notification unit 56 displays, for example, "Please set the reference rotation position P2." The operator rotates the handle 501 to set the reference rotation position P2. The process proceeds to step S6.

[0086] In step S6, the control unit 50 restricts the execution of the autonomous driving mode. Even if the control unit 50 is instructed to start the execution of the autonomous driving mode, the control unit 50 restricts the execution of the autonomous driving mode until the setting of the reference rotation position P2 is completed. Then, the processing ends.

[0087] Next, the process of setting the reference rotation position P2 will be described. The process of setting the reference rotation position P2 is performed independently of and in parallel with the operation mode control process. As shown in Fig. 9, a program stored in the storage device of the storage unit 55 (see Fig. 2) causes the processor of the control unit 50 to execute the processes from step S11 to step S17.

[0088] 9, in step S11, the control unit 50 reads various pieces of information, and then the process proceeds to step S12.

[0089] In step S12, the control unit 50 determines whether the power supply 59 has been turned on. If the control unit 50 determines that the power supply 59 has not been turned on (No in step S12), the process ends. If the control unit 50 determines that the power supply 59 has been turned on (Yes in step S12), the process proceeds to step S13.

[0090] In step S13, the setting unit 52 starts setting the reference rotation position P2 of the motor 505. The operator operates the combine harvester 1 to the destination in manual operation mode. The setting unit 52 sets the reference rotation position P2 based on the left rotation amount V1 and the right rotation amount V2. The process proceeds to step S14.

[0091] In step S14, the control unit 50 determines whether or not setting of the reference rotation position P2 of the motor 505 has been completed. If the control unit 50 determines that setting of the reference rotation position P2 of the motor 505 has not been completed (No in step S14), the process returns to step S13. If the control unit 50 determines that setting of the reference rotation position P2 of the motor 505 has been completed (Yes in step S14), the process proceeds to step S15.

[0092] In step S15, control unit 50 controls notification unit 56 to notify that setting of reference rotation position P2 of motor 505 has been completed. Notification unit 56, for example, turns on a lamp indicating that setting of reference rotation position P2 has been completed. The process proceeds to step S16.

[0093] In step S16, the control unit 50 determines whether the number of times the reference rotation position P2 has been set is equal to or greater than a threshold value K. If the control unit 50 determines that the number of times the reference rotation position P2 has been set is less than the threshold value K (No in step S16), the process returns to step S13. If the control unit 50 determines that the number of times the reference rotation position P2 has been set is equal to or greater than the threshold value K (Yes in step S16), the process proceeds to step S17.

[0094] In step S17, the control unit 50 updates the reference rotation position P2 to a new one. The control unit 50 registers the latest reference rotation position P2 set this time in place of the previously registered reference rotation position P2. The control unit 50 also resets a counter for counting the number of times the reference rotation position P2 has been set. The process then ends.

[0095] The embodiments of the present disclosure have been described above with reference to the drawings. However, the present disclosure is not limited to the above embodiments and can be implemented in various forms without departing from the spirit and scope of the present disclosure. Furthermore, the components disclosed in the above embodiments can be modified as appropriate. For example, some of the components shown in one embodiment may be added to the components of another embodiment, or some of the components shown in one embodiment may be deleted from the embodiment.

[0096] Furthermore, the drawings mainly show each component in a schematic manner to facilitate understanding of the present disclosure, and the thickness, length, number, spacing, etc. of each component shown in the drawings may differ from the actual configuration due to the convenience of creating the drawings. Furthermore, the configuration of each component shown in the above embodiment is an example and is not particularly limited, and it goes without saying that various modifications are possible within a scope that does not substantially deviate from the effects of the present disclosure.

[0097] (1) As described with reference to Figures 1 to 9, in the above embodiment, the handle 501 is a round handle, but this is not limiting. Any operating member can be used, such as a stick-shaped lever or a non-circular handle, as long as it can at least operate the steering shaft.

[0098] (2) As described with reference to FIGS. 1 to 9, the above embodiment shows an example of a combine harvester 1, but is not limited to this. The present invention can be applied to at least any work vehicle capable of automatic driving, such as a tractor. The present invention can also be applied to a control device for an automatically driven work vehicle.

[0099] (3) As described with reference to FIGS. 1 to 9 , in the above embodiment, the reference rotation position P2 is set during the period from immediately after the power supply 59 is turned on until an instruction to start the automatic driving mode is given. However, this is not limiting. It is sufficient that the reference rotation position P2 be set at least before an instruction to start the automatic driving mode is given. The reference rotation position P2 may be set during the period from a predetermined time after the power supply 59 is turned on until an instruction to start the automatic driving mode is given. Furthermore, if the point at which the automatic driving mode is to be started is known in advance, the time from the power supply 59 being turned on until the reference rotation position P2 is set may be set according to the distance from the point at which the power supply 59 is turned on to the point at which the automatic driving mode is to be started.

[0100] (4) As described with reference to FIGS. 1 to 9 , in the above embodiment, the reference rotation position P2 of the motor 505 is set based on the amount of rotation V1 when passing from the rotation start position Pa to the rotation reference position P1L and the amount of rotation V2 when passing from the rotation start position Pa to the rotation reference position P1R. However, this is not limiting. The reference rotation position P2 of the motor 505 may be set based on the amount of rotation V when passing at least a single rotation reference position P1. Furthermore, the reference rotation position P2 of the motor 505 may be set based on the amount of rotation V when passing three or more rotation reference positions P1. Furthermore, when two rotation reference positions P1 are used, the rotation reference positions P1 that are not symmetrical with respect to the neutral position N may be used.

[0101] (5) As described with reference to FIGS. 1 to 9, in the above embodiment, an example was shown in which the reference rotation position P2 of the motor 505 was set to the neutral position N, but this is not limiting. The reference rotation position P2 of the motor 505 may be set to a position other than the neutral position N. For example, if the reference rotation position P2 of the motor 505 is set 30 degrees to the right from the neutral position N, the combine 1 can be driven straight by steering the motor 505 30 degrees to the left from the reference rotation position P2.

[0102] (6) As described with reference to FIGS. 1 to 9 , in the above embodiment, when the reference rotation position P2 calculated based on a pair of rotation amounts, namely, the rotation amount V1 of the rotation reference position P1L and the rotation amount V2 of the rotation reference position P1R, is set to be equal to or greater than the threshold value K, the latest reference rotation position P2 is registered. However, this is not limited to this. Alternatively, an average value of multiple reference rotation positions P2, including the latest reference rotation position P2, may be calculated and registered as a new reference rotation position P2. Any calculation method may be used. Alternatively, a first threshold may be set for the rotation amount V1 of the rotation reference position P1L, and a second threshold may be set for the rotation amount V2 of the rotation reference position P1R. When the rotation amount V1 is set to be equal to or greater than the threshold value K, the new reference rotation position P2 may be registered. In this case, the first threshold and the second threshold may be the same or different.

[0103] (7) As described with reference to FIGS. 1 to 9 , in the above embodiment, the rotation amount V of the motor 505 is detected when switching from the ON region to the OFF region or from the OFF region to the ON region. However, this is not limited to this. We verified the error and maximum error between the calculated neutral position N calculated based on the rotation amount V at the off-edge when switching from the ON region to the OFF region and the actual neutral position N, and the error and maximum error between the calculated neutral position N calculated based on the rotation amount V at the on-edge when switching from the OFF region to the ON region and the actual neutral position N. As a result of the verification, the error and maximum error at the off-edge were approximately half the error and maximum error at the on-edge. Therefore, the reference rotation position P2 may be calculated based on the rotation amount V at the off-edge. If the reference rotation position P2 calculated at the off-edge is set to be equal to or greater than a threshold, a new reference rotation position P2 may be registered.

[0104] (8) As described with reference to Fig. 8, in the above embodiment, even if the reference rotation position P2 has not been set, if an instruction to start the autonomous driving mode has not been issued, no notification is given. However, this is not limited to this. If the reference rotation position P2 has not been set, a notification may be given regardless of an instruction to start the autonomous driving mode.

[0105] An operation mode control according to a modified example will be described with reference to Fig. 10. Fig. 10 is a flowchart showing operation mode control according to a modified example. Below, differences from the flowchart in Fig. 8 will be mainly described.

[0106] 10, in step S1, the control unit 50 reads various pieces of information, and then the process proceeds to step S3.

[0107] In step S3, the control unit 50 determines whether the reference rotation position P2 has been set. If the control unit 50 determines that the reference rotation position P2 has not been set (No in step S3), the process proceeds to step S5. If the control unit 50 determines that the reference rotation position P2 has been set (Yes in step S3), the process proceeds to step S21.

[0108] In step S21, the control unit 50 determines whether or not an instruction to start the autonomous driving mode has been issued. If the control unit 50 determines that an instruction to start the autonomous driving mode has not been issued (No in step S21), the process ends. If the control unit 50 determines that an instruction to start the autonomous driving mode has been issued (Yes in step S21), the process proceeds to step S4.

[0109] In step S4, the control unit 50 executes the automatic driving mode, and the process ends.

[0110] If the answer is No in step S3, in step S5, the control unit 50 controls the notification unit 56 to notify that the reference rotation position P2 has not been set. The process proceeds to step S6.

[0111] In step S6, the control unit 50 restricts the execution of the autonomous driving mode, and the process ends.

[0112] This application discloses the following supplementary notes, which are not intended to limit the present invention.

[0113] (Appendix 1) A running part; a shaft for controlling the direction of travel of the traveling unit; a motor for driving the shaft; a control unit that sets a reference rotation position of the motor based on an amount of rotation of the shaft that is smaller than a maximum amount of rotation of the shaft from a rotation reference position of the shaft; A work vehicle equipped with:

[0114] (Appendix 2) 2. The work vehicle according to claim 1, wherein the control unit sets the reference rotation position of the motor based on at least one of a left rotation amount and a right rotation amount of the shaft from a rotation reference position of the shaft.

[0115] (Appendix 3) 3. The work vehicle according to claim 2, wherein the left rotation amount and the right rotation amount of the shaft are the same rotation amount.

[0116] (Appendix 4) a detection unit that outputs a detection signal in response to the rotation position of the shaft being located at a first rotation position on the left side or a second rotation position on the right side with respect to a rotation reference position of the shaft; the rotation reference position of the shaft indicates a neutral position of the shaft corresponding to the linear direction of the traveling part, 4. The work vehicle according to claim 1, wherein the control unit sets a reference rotation position of the motor based on a detection signal from the detection unit.

[0117] (Appendix 5) 5. The work vehicle according to claim 4, wherein the detection unit is an angular displacement sensor that detects the amount of rotation of the shaft using electromagnetic induction.

[0118] (Appendix 6) 6. The work vehicle according to any one of Supplementary Note 1 to Supplementary Note 5, wherein the control unit updates the reference rotation position of the motor when the number of times the reference rotation position of the motor has been set exceeds a threshold value.

[0119] (Appendix 7) The work vehicle is capable of executing an automatic driving mode, 7. The work vehicle according to any one of Supplementary Note 1 to Supplementary Note 6, wherein the control unit restricts execution of the autonomous driving mode until a reference rotation position of the motor is set.

[0120] (Appendix 8) The work vehicle is a power supply that generates power to supply to the motor; an operation unit that receives an operation to supply the electric power to the motor; a reception unit that receives an instruction to execute the autonomous driving mode; and 8. The work vehicle according to any one of Supplementary Note 1 to Supplementary Note 7, wherein the control unit sets a reference rotation position of the motor during a period from when the operation unit receives an operation to supply power to the motor until when the reception unit receives an instruction to start the autonomous driving mode.

[0121] (Appendix 9) A running part; a shaft for controlling the direction of travel of the traveling unit; a motor for driving the shaft; a detection unit that detects the amount of rotation of the shaft that controls the traveling direction of the traveling unit; A control device mounted on a work vehicle comprising: an acquisition unit that acquires the rotation amount of the shaft from the detection unit; a setting unit that sets a reference rotation position of the motor based on an amount of rotation of the shaft that is smaller than a maximum amount of rotation of the shaft from a reference rotation position of the shaft; A control device comprising: [Industrial Applicability]

[0122] The present invention relates to a work vehicle and a control device, and has industrial applicability. [Explanation of symbols]

[0123] 1: Combine (work vehicle) 50: Control unit 51: Acquisition part 52: Setting section 57:Operation section 58: Reception 59: Power supply 67: Rotation angle sensor (detection part) 102: Running device (running part) 503: First shaft (shaft) 505: Motor K: threshold N: Neutral position P1: Rotation reference position P1L: Rotation reference position (first rotation position) P1R: Rotation reference position (second rotation position) P2: Reference rotation position V: Amount of rotation V1: Left rotation amount V2: Right rotation amount V3: Amount of rotation VA: Maximum rotation amount

Claims

1. A running part; a shaft for controlling the direction of travel of the traveling unit; a motor that drives the shaft; a control unit that sets a reference rotation position of the motor based on an amount of rotation of the shaft that is smaller than a maximum amount of rotation of the shaft from a rotation reference position of the shaft; A work vehicle equipped with:

2. The work vehicle according to claim 1 , wherein the control unit sets the reference rotation position of the motor based on at least one of a left rotation amount and a right rotation amount of the shaft from a rotation reference position of the shaft.

3. The work vehicle according to claim 2 , wherein the left rotation amount and the right rotation amount of the shaft are the same rotation amount.

4. a detection unit that outputs a detection signal in response to the rotational position of the shaft being at a first rotational position on the left side or a second rotational position on the right side with respect to a rotational reference position of the shaft; the rotation reference position of the shaft indicates a neutral position of the shaft corresponding to the linear direction of the traveling part, The work vehicle according to claim 1 or 2, wherein the control unit sets a reference rotation position of the motor based on a detection signal from the detection unit.

5. The work vehicle according to claim 4 , wherein the detection unit is an angular displacement sensor that detects the amount of rotation of the shaft using electromagnetic induction.

6. The work vehicle according to claim 1 or 2, wherein the control unit updates the reference rotation position of the motor when the number of times the reference rotation position of the motor is set exceeds a threshold value.

7. The work vehicle is capable of executing an automatic driving mode, The work vehicle according to claim 1 or 2, wherein the control unit restricts execution of the autonomous driving mode until a reference rotation position of the motor is set.

8. The work vehicle is a power supply that generates power to supply to the motor; an operation unit that receives an operation to supply the electric power to the motor; a reception unit that receives an instruction to execute the autonomous driving mode; and 8. The work vehicle according to claim 7, wherein the control unit sets a reference rotation position of the motor during a period from when the operation unit accepts an operation to supply the power to the motor until when the acceptance unit accepts an instruction to start the autonomous driving mode.

9. A running part; a shaft for controlling the direction of travel of the traveling unit; a motor that drives the shaft; a detection unit that detects the amount of rotation of the shaft that controls the traveling direction of the traveling unit; A control device mounted on a work vehicle comprising: an acquisition unit that acquires the rotation amount of the shaft from the detection unit; a setting unit that sets a reference rotation position of the motor based on an amount of rotation of the shaft that is smaller than a maximum amount of rotation of the shaft from a reference rotation position of the shaft; A control device comprising:

Images