Work vehicle

Abstract

To perform planting with high accuracy even when a current position cannot be acquired in comparison to a technique of performing planting by acquiring the current position through communication with an artificial satellite.SOLUTION: A work vehicle includes a control unit (300) that controls a planting device (3) via a drive source (M1) to plant seedlings at predetermined positions. The control unit (300) drives the drive source (M1) on the basis of the acquisition result of position acquisition means (301) when the current position is acquired by the position acquisition means (301), and drives the drive source (M1) on the basis of the detection result of the rotation speed of rotation speed detection means (302) when the current position is not acquired by the position acquisition means (301).SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a work vehicle, and more particularly to a work vehicle having a planting device such as a rice transplanter or a seedling transplanter. [Background technology]

[0002] In work vehicles such as rice transplanters and seedling transplanters, a technology is known in which the position (target phase) for planting seedlings is calculated based on position information obtained by a Global Navigation Satellite System (GNSS), and the planting unit (200) is controlled based on the actual phase and target phase of the planting unit (200) (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6342344 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional technology, communication with GNSS satellites can sometimes fail to obtain accurate position information (so-called "lost") due to various factors, such as the positional relationship between the satellite's position and surrounding buildings and bridges, and signal reflection from surrounding buildings. Errors can also occur in GNSS signal processing. In the technology described in Patent Document 1, if a loss or error occurs during planting work, the planting positions of seedlings cannot be calculated accurately, causing the planting positions (planting intervals) to vary, or even making it impossible to perform the planting work itself.

[0005] The technical objective of the present invention is to perform planting with high accuracy even when the current location cannot be obtained, compared to a technology in which planting is performed by obtaining the current location through communication with an artificial satellite. [Means for solving the problem]

[0006] The above-mentioned problems of the present invention are solved by the following means. The invention described in claim 1 is a work vehicle comprising: a traveling body (1) having a traveling device (7); a planting device (3) supported by the traveling body (1) for planting seedlings in a field; a position acquisition means (301) for acquiring a current position of the traveling body (1); a drive source (M1) for driving the planting device (3); a rotation speed detection means (302) for detecting the rotation speed of the traveling device (7); and a control unit (300) for controlling the planting device (3) via the drive source (M1) to plant seedlings in a predetermined position, the control unit (300) driving the drive source (M1) based on the acquisition result of the position acquisition means (301) when the current position is acquired by the position acquisition means (301), and driving the drive source (M1) based on the detection result of the rotation speed of the rotation speed detection means (302) when the current position is not acquired by the position acquisition means (301).

[0007] The invention described in claim 2 is the work vehicle described in claim 1, characterized in that it is provided with a control unit (300) that calculates a slip ratio (L1 / L0) which is the ratio of the first travel distance (L1) to the second travel distance (L0) based on a first travel distance (L1) based on the change in the current position acquired by the position acquisition means (301) and a second travel distance (L0) based on the rotation speed of the traveling device (7) detected by the rotation speed detection means (302), and controls the drive source (M1) using the slip ratio (L1 / L0) when driving the drive source (M1) based on the detection result of the rotation speed of the rotation speed detection means (302).

[0008] The invention described in claim 3 is the work vehicle described in claim 2, characterized in that it includes a regenerative braking device (BR) that brakes the planting device (3) and generates electricity when braking, a load detection means (305) that detects the load on the drive source (M1), and the control unit (300) that controls the regenerative braking device (BR) to brake the planting device (3) when a load exceeding a predetermined load is detected based on the detection result of the load detection means (305).

[0009] The invention described in claim 4 is the work vehicle described in claim 1, characterized in that it is equipped with the control unit (300) that, when the rotation direction of the driving source (M1) during planting is positive, and when the target phase of the rotation direction of the driving source (M1) determined based on the current position acquired by the position acquisition means (301) is in a negative position with respect to the current phase of the driving source, sets the current phase to the target phase.

[0010] The invention described in claim 5 is the work vehicle described in claim 1, characterized in that it comprises a second driving source (M2) that changes the planting depth, which is the depth at which seedlings are planted in a field by the planting device (3), an input member (SW1) through which the planting depth is input by an operator, a float (42) that is provided on the planting device (3) and detects the condition of the field based on contact with and separation from the field, and the control unit (300) that stops operation of the second driving source (M2) when it detects the float (42) having come into contact with the field, even if an input to change the planting depth is given.

[0011] The invention described in claim 6 is the work vehicle described in claim 5, characterized in that it is provided with the control unit (300) that stops operation of the second drive source (M2) when the grounding of the float (42) is detected and an input is given to reduce the planting depth.

[0012] The invention described in claim 7 is the work vehicle described in claim 5, characterized in that it is provided with the control unit (300) that, when it detects the grounding of the float (42) and an input is made to change the planting depth, displays on a display (101) that the planting depth will not be changed. Effect of the Invention

[0013] According to the invention described in claim 1, when the current position is acquired by the position acquisition means (301), the drive source (M1) is driven based on the acquisition result of the position acquisition means (301), and when the current position is not acquired by the position acquisition means (301), the drive source (M1) is driven based on the detection result of the rotation speed by the rotation speed detection means (302). Compared to a technology in which the current position is acquired by communicating with an artificial satellite and then planting is performed, planting can be performed with high accuracy even when the current position cannot be acquired.

[0014] According to the invention of claim 2, in addition to the effect of the invention of claim 1, by using the slip ratio (L1 / L0) when driving the drive source (M1) based on the detection result of the rotation speed of the rotation speed detection means (302), the planting accuracy can be improved compared to the case where the slip ratio is not taken into consideration. According to the invention described in claim 3, in addition to the effects of the invention described in claim 2, when the load on the drive source (M1) exceeds a predetermined load, the regenerative braking device (BR) is controlled, thereby making it possible to stabilize planting and to generate electricity using the regenerative braking device (BR), thereby enabling efficient use of electricity.

[0015] According to the invention of claim 4, in addition to the effect of the invention of claim 1, it is possible to prevent the drive source (M1) from rotating in reverse, and to prevent damage to members that are not adapted to reverse rotation. According to the invention described in claim 5, in addition to the effects of the invention described in claim 1, damage to the second drive source (M2) and the float (42) can be suppressed compared to the case where the planting depth is changed while the grounding of the float (42) is sensed.

[0016] According to the invention described in claim 6, in addition to the effect of the invention described in claim 5, when an input is made to decrease the planting depth while the float (42) is grounded, damage to the second driving source (M2) and the float (42) can be suppressed compared to a case in which the second driving source (M2) is operated. According to the invention as set forth in claim 7, in addition to the effect of the invention as set forth in claim 5, the fact that the planting depth will not be changed can be displayed on the display (101), thereby making it possible to notify the operator. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a left side view of a seedling transplanter according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view of the seedling transplanter according to the embodiment. [Diagram 3] 3A and 3B are explanatory diagrams of a rotor for ground leveling according to an embodiment, in which FIG. 3A is a plan view and FIG. 3B is a side view. [Figure 4] FIG. 2 is a functional block diagram of a control unit according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] An embodiment of the present invention will be described below. A four-row riding rice transplanter, which is an example of a work vehicle according to the present invention and is one embodiment of a seedling transplanter, will be described in detail with reference to the drawings. As shown in the side view of Fig. 1 and the plan view of Fig. 2, the riding rice transplanter (work vehicle) is configured to function as a riding fertilizer rice transplanter by mounting a seedling planting device 3, which is a type of work machine, to a traveling body 1 via a lifting link device 2 and also by providing a fertilizer device 4. The traveling body 1 is a four-wheel drive vehicle having a pair of front wheels 6, 6 and rear wheels 7, 7 on each side, which are an example of a traveling device. In this specification, the left and right sides of the rice transplanter in the forward movement direction are referred to as the left and right sides, respectively, and the forward movement direction is referred to as the front side and the backward movement direction is referred to as the rear side.

[0019] As shown in FIG. 1, a transmission case 11 and a travel motor 12 are disposed on main frames 10a, 10b. A hydraulic pump 13 is integrally assembled with the transmission case 11 on the rear side of the transmission case 11, and a steering post 14 protrudes from the front upper part of the transmission case 11. A steering handle 16 is provided at the upper end of the steering post 14. A step floor 19, which serves as a floor for operation, is attached to the top of the aircraft, and a pilot's seat 20 is installed above the traveling motor 12. A gear shift operation lever (travel operation member) 17 is provided to the right of the steering handle 16.

[0020] An operation panel (not shown) is provided on the steering post 14 in front of the cockpit 20. A ridge clutch lever 18 is provided on the right side of the cockpit 20. The front wheels 6, 6 are journaled on front wheel support cases 22, 22 that are provided on the sides of the transmission case 11 so that their direction can be changed. The rear wheels 7, 7 are journaled via rear wheel supports 30 on rear wheel transmission cases 24, 24 attached to both left and right ends of a left and right frame 37. The left and right frames 37 are supported on the rear ends of the main frames 10a, 10b.

[0021] As shown in FIG. 1 and FIG. 2, part of the power transmission mechanism to the rear wheels 7 is shown. The rotational power of a driving motor 12 is transmitted to the inside of a transmission case 11 . The rear end portions of the rear output shafts 11a, 11b protrude rearward from the transmission case 11, and left and right rear wheel transmission shafts 35, 35 which transmit power to the rear wheel transmission cases 24, 24 are connected to these protruding ends. The left and right rear wheel transmission shafts 35, 35 drive and rotate the left and right rear wheels 7, 7, respectively.

[0022] The seedling planting device 3 is mounted on the traveling vehicle body 1 by a lifting link device 2 so as to be able to rise and fall freely. The upper end of the piston of a general lift cylinder 36 (Figure 1), the base of which is rotatably mounted on the traveling body 1, is connected to the lifting link device 2, and pressurized oil is supplied to and discharged from the hydraulic pump 13 mounted on the traveling body 1 via a lifting valve (not shown) to the lift cylinder 36, thereby extending and retracting the piston of the lift cylinder 36, thereby moving the seedling planting device 3 connected to the lifting link device 2 up and down.

[0023] The seedling planting device 3 is composed of a planting transmission case 38, which also serves as a frame and is mounted on the rear of the lifting link device 2 via a left and right frame 37 in a rolling manner, a seedling carrier (seedling tank) 39 that is supported by a support member provided on the planting transmission case 38 and moves back and forth in the left and right directions of the machine body, a seedling planting tool 41 that is mounted on the rear end of the planting transmission case 38 and plants the seedlings one by one in the field from the bottom end of the seedling carrier 39, and a center float (sensor float) 42 and a side float 43, which are ground leveling bodies whose rear parts are pivotally supported on the lower part of the planting transmission case 38 and whose front parts are mounted so as to be able to swing up and down. The center float 42 and the side float 43 are provided to level the field and also to level the front of the field where the seedlings are planted by the seedling planting tool 41.

[0024] The PTO transmission shaft 45 (FIG. 1) has universal joints at both ends and is provided to transmit power from a PTO motor (not shown) to the planting transmission case 38 of the seedling planting device 3. The seedling planting device 3 has a four-row planting configuration and is equipped with a planting transmission case 38 that also serves as a frame, a seedling carrier 39 that carries the seedlings and moves back and forth to supply the seedlings one by one to the seedling outlet 39a of each row (Figure 2), and a seedling planting tool 41 that plants the seedlings supplied to the seedling outlet 39a in the field.

[0025] FIG. 3 is an explanatory diagram of a ground leveling rotor according to an embodiment, in which FIG. 3(A) is a plan view and FIG. 3(B) is a side view. As shown in FIG. 1, a ground leveling rotor 70a is disposed in front of the center float 42, and the ground leveling rotor 70a is disposed forward of a ground leveling rotor 70b which is disposed in front of the side float 43. In Figure 3, power is transmitted to the ground leveling rotor 70b from a rotor motor M3 as an example of a third drive source via a transmission rod 201, and power is transmitted to the ground leveling rotor 70a from a pair of chains (not shown) in a pair of left and right chain cases 71, 71 (only the left side is shown in Figure 3 (A)) to which power is transmitted from the drive shaft 70d of the ground leveling rotor 70b.

[0026] In the embodiment, the rotor motor M3 is attached to the side of the lower link 202 of the lifting link device 2. In the conventional configuration, the drive of the ground leveling rotors 70a, 70b is taken out from the rear wheel transmission case 24 of the rear wheel 7, and the connection angle (joint angle) of the connection member extending from the rear wheel transmission case 24 to the chain case 71 of the ground leveling rotors 70a, 70b becomes steep, which is disadvantageous for transmission. There is also a problem that the input side (rear wheel transmission case 24 side) of the connection member is easily buried in mud. In response to these, in the embodiment, the rotor motor M3 is supported by the lower link 202, and the transmission rod 201 extends from above the rear wheel transmission case 24. Therefore, the joint angle is gentle, which suppresses fluctuations during transmission and makes it difficult for the input side of the transmission rod 201 to be buried in mud.

[0027] In addition, the rotor motor M3 is installed at an angle so that the direction is along the extension direction (diagonally downward direction) of the transmission rod 201. Therefore, by installing the rotor motor M3 at an angle, the harness from the rotor motor M3 is arranged so that it can be easily routed inside the traveling vehicle body 1. 3(B), the lower end of a lifting rod 206 is rotatably connected to the chain cases 71, 71, and a lifting gear 207 is rotatably connected to the upper end of the lifting rod 206. Driving force is transmitted to the lifting gear 207 from a rotor lifting motor M4, which is an example of a fourth driving source. Therefore, in response to forward and reverse rotation of the rotor lifting motor M4, the lifting rod 206 moves up and down, and the ground leveling rotors 70a, 70b move in the up and down direction, making it possible to adjust the height.

[0028] The rear wheel transmission case 24 of the rear wheel 7 is attached to both left and right ends of the left and right frames 37 and is journalled on the rear wheel support 30 . Rotation of the rear wheel transmission case 24 causes the axle 23 of the rear wheel 7 to move up and down integrally with the rear wheel transmission case 24. Power is transmitted to the rear wheel transmission case 24 from the transmission case 11 via left and right rear wheel transmission shafts 35.

[0029] The fertilizer application device 4 discharges fertilizer from the fertilizer tank 67 downward in fixed amounts by the fertilizer delivery section 68, and the discharged fertilizer is transported by the blower 69 through the fertilizer application hose 62 to the fertilizer application guide 80, where it is dropped into a fertilizer application furrow formed near the side of the seedling planting row by a furrow making body 82 provided in front of the fertilizer application guide 80. In addition, a pedal 86 (Figure 2) can operate both the main clutch and the left and right rear wheel brake devices (not shown) and is located on the lower right side of the steering handle 16. When this pedal 86 is depressed, the main clutch is disengaged, and then the left and right rear wheel brakes are applied, bringing the aircraft to a stop.

[0030] (Explanation of the control unit) FIG. 4 is a functional block diagram of the control unit according to the embodiment. In the block diagram of FIG. 4, elements that are not related to the description of the embodiment of the present invention are not shown and are not described. The seedling transplanter of the embodiment is configured to be able to send and receive information via a communication line with a tablet terminal as an example of a terminal and a distribution server as an example of an information processing device.

[0031] (Explanation of the control unit of the seedling transplanter) The seedling transplanter of the embodiment has a control unit 300 that controls each function. The control unit 300 has an input / output interface I / O that performs input and output of signals with the outside. The control unit 300 also has a ROM (read-only memory) that stores programs and information for performing necessary processing. The control unit 300 also has a RAM (random access memory) for temporarily storing necessary data. The control unit 300 also has a CPU (central processing unit) that performs processing according to the programs stored in the ROM or the like. Therefore, the control unit 300 of the embodiment is composed of a small information processing device, a so-called microcomputer. Therefore, the control unit 300 can realize various functions by executing the programs stored in the ROM or the like.

[0032] The control unit 300 receives signals from signal input elements such as a touch panel 101, which is an example of an input unit and an example of a display, a GNSS positioning device SN0, a rotation speed sensor SN1, a PTO load ammeter SN2, a motor phase sensor SN3, a float sensor SN4, a rotor load sensor SN5, a planting depth switch SW1, and various other sensors not shown. The GNSS positioning device SN0, which is an example of a position acquisition device, detects the current position of the traveling vehicle body 1 based on signals from artificial satellites.

[0033] The rotation speed sensor SN1, which is an example of a rotation speed detection member, measures the rotation speed of the rear wheel 7, which is a driving wheel. Note that, although the embodiment has been described as an example of measuring the rotation speed of the rear wheel 7, it is also possible to configure the sensor SN1 to measure the rotation speed of the front wheel 6. The PTO load ammeter SN2, which is an example of a load detection member, detects the load current flowing through the PTO motor M1. The motor phase sensor SN3, which is an example of a phase detection member, detects the phase of the PTO motor M1.

[0034] The float sensor SN4, which is an example of a contact detection member, detects whether the center float 42 is detected in the field. In this embodiment, the center float 42 is supported rotatably around a support shaft (not shown), and the float sensor SN4, which is configured by a potentiometer that detects the rotation angle, is disposed on the support shaft. Therefore, when the center float 42 moves in a direction away from the field relative to the field due to a depression in the field or the like (floating above the field), the center float 42 rotates around the support shaft, and the float sensor SN4 detects the change in angle. Note that the location where the float sensor SN4 is installed is not limited to the center float 42, and it may also be the side float 43.

[0035] The rotor load sensor SN5, which is an example of a ground leveling load detection member, detects the load of the rotor motor M3. The rotor load sensor SN5 detects the load by detecting the load current value of the rotor motor M3. The planting depth switch SW1, which is an example of a planting depth input member, allows an operator to input the planting depth of the seedlings using the seedling planting tool 41.

[0036] The control unit 300 can also send control signals to the fertilizer applicator 4 as an example of a controlled element, the travel motor 12, the steering wheel 16, the lift cylinder 36, the PTO motor M1 as an example of a drive source, the regenerative brake BR as an example of a regenerative braking device, the planting depth adjustment motor M2 as an example of a second drive source, the rotor motor M3, the rotor lifting motor M4, and the like, to control the travel and stopping of the travel body 1, the operation and stopping of the fertilizer applicator 4, and the lifting and lowering of the seedling planting device 3. The control unit 300 can also output control signals to the touch panel 101 as an example of a display device to display work information and work status.

[0037] In FIG. 4, the control unit 300 according to the embodiment has the following functional means (program modules). The position acquisition means 301 detects the current position of the traveling vehicle body 1 based on the detection result of the GNSS positioning device SN0.

[0038] The rotation speed detection means 302 detects the rotation speed of the rear wheel 7 based on the detection result of the rotation speed sensor SN1. The traveling distance calculation means 303 calculates the traveling distance L0 (an example of a second moving distance) of the traveling vehicle body 1 based on the rotation speed detected by the rotation speed detection means 302 and the outer circumferential length of the rear wheel .

[0039] The slip ratio calculation means 304 calculates a slip ratio, which is the degree to which the traveling vehicle body 1 spins freely during traveling, i.e., slips. The slip ratio calculation means 304 of the embodiment calculates, as a slip ratio, a ratio (L1 / L0) of a moving distance L1 (one example of a first moving distance) per unit time from the transition of the current position detected by the position acquisition means 301 to a traveling distance L0 per unit time calculated by the traveling distance calculation means 303. That is, while the vehicle should have moved by the traveling distance L0 from the rotation of the rear wheel 7, when a slip occurs, the actual moving distance L1 becomes smaller. Therefore, it can be seen that the smaller the slip ratio value (L1 / L0), the more slip there is. Note that the method of calculating the slip ratio is not limited to the exemplified method, and it is also possible to adopt, for example, a mode in which the ratio of the amount of progress that could not be made due to slip (=1-L1 / L0) is adopted as the slip ratio.

[0040] The work machine load detection means 305 detects the load on the seedling planting device 3 based on the detection result of the PTO load ammeter SN2. When the work is performed and the PTO motor M1 is driven, a current flows, and when the load on the PTO motor M1 increases, the output current value of the PTO motor M1 increases. When the seedling planting tool 41 rotates in conjunction with the planting work, periodic fluctuations in the output current value of the PTO motor M1 are detected. The phase detection means 306 detects the rotational position (rotational phase) of the output shaft of the PTO motor M1 based on the detection result of the motor phase sensor SN3. The phase is determined by taking a predetermined rotational position as the origin (phase 0 degrees) and the rotation direction during planting work as positive, and detects the current rotational position (current phase).

[0041] The grounding detection means 307 detects whether the center float 42 is in contact with the field (floating) or not based on the detection result of the float sensor SN4. In this embodiment, based on the angle detected by the float sensor SN4, it is determined that the center float 42 is in contact with the field when a predetermined range or more of the lower surface of the center float 42 is in contact with the field surface, and it is determined that the center float 42 is floating (not in contact with the field) when the center float 42 has rotated and is completely separated from the field surface or when only a part of the rear end is in contact with the field surface.

[0042] The travel control means 308 travels the traveling body 1 along a predetermined work path when an input to execute automatic travel is made from the touch panel 101. The travel control means 308 of the embodiment controls the travel motor 12 and the steering wheel 16 based on the position information acquired by the position acquisition means 301 and the predetermined work path, and travels the traveling body 1 along the work path at a predetermined work speed. The work path, work start position, work end position, etc. can be automatically created from the shape of the field, or a configuration in which the worker manually inputs the work start position, work end position, work path, etc. can also be used.

[0043] The working machine control means 309 has a planting control means 309A, a lifting control means 309B, a planting depth control means 309C, and a soil leveling rotor control means 309D, and controls the seedling planting device 3 as an example of a working machine. The planting control means 309A controls the seedling planting device 3 to plant seedlings in the field. The planting control means 309A in the embodiment controls the drive / stop and rotation speed of the PTO motor M1 to adjust the time (timing) when the seedling planting tool 41 plants the seedlings in the field, and plants the seedlings in a predetermined planting position. In other words, the drive of the PTO motor M1 is controlled so that the seedlings are planted at a predetermined interval (between plants).

[0044] The planting control means 309A of the embodiment calculates the planting position of the next seedling to be a position that is a specified distance away from the previous planting position of the seedling, and plants the seedling in the field at the planting position of the next seedling based on the position information acquired by the position acquisition means 301. It is preferable to calculate the planting position automatically from the work start position and the set values ​​for the spacing between plants (planting interval), but it is also possible to configure the planting position to be manually set in advance by the worker. When automatically calculating the planting position, it is also possible to calculate the planting position so that the spacing between plants in the direction of travel and the direction perpendicular to the direction of travel are aligned, i.e., so-called double-row planting.

[0045] Here, when the current position is acquired by the position acquisition means 301, the PTO motor M1 is driven based on the current position acquired by the position acquisition means 301 to plant the seedlings. On the other hand, when the current position cannot be acquired due to the loss of position information or the occurrence of an error, the PTO motor M1 is driven to plant the seedlings based on the travel distance L0 from the previous planting position of the seedlings calculated by the travel distance calculation means 303. That is, the PTO motor M1 is driven based on the detection result of the rotation speed by the rotation speed detection means 302.

[0046] In particular, in the planting control means 309A of the embodiment, when the current position is not acquired, the PTO motor M1 is driven using the slip ratio calculated by the slip ratio calculation means 304. Specifically, the travel distance L0 detected by the travel distance calculation means 303 is the travel distance when there is no slip, and the actual travel distance is highly likely to be the value of (travel distance) x (slip ratio). If the slip ratio is not taken into account, if slip occurs during travel, the seedlings may be planted at a position just before reaching the target planting position, and the spacing between plants (planting intervals) may become narrow. In contrast, in the planting control means 309A of the embodiment, the seedlings are planted by the seedling planting tool 41 when the travel distance taking the slip ratio into account becomes the target spacing between plants. Therefore, in the embodiment, the PTO motor M1 is driven to plant the seedlings based on the travel distance taking the slip ratio into account, and the spacing between plants is suppressed from being shifted compared to when the slip ratio is not taken into account. In addition, when considering the slip ratio, it is desirable to configure the system so that the worker can judge the condition of the field (the amount of water and the hardness or softness of the soil), etc., and manually fine-tune the slip ratio using a button or switch, etc.

[0047] In addition, the planting control means 309A of the embodiment controls the regenerative brake BR to brake the seedling planting device 3 when a load exceeding a predetermined load is detected based on the detection result of the work machine load detection means 305. In the planting control means 309A of the embodiment, if the load fluctuation history (profile) detected by the work machine load detection means 305 during planting work deviates from (exceeds) the predetermined load profile, it is determined that an excessive load is applied to the PTO motor M1. If an excessive load is applied, so-called pulsation occurs when a torque motor is used as the PTO motor M1, and there is a problem of unstable operation. In the embodiment, when it is determined that an excessive load is applied, the regenerative brake BR is operated to brake (apply the brake) the PTO motor M1 for safety. Therefore, safety can be ensured, and pulsation is also suppressed when a torque motor is used.

[0048] In addition, in the embodiment, a regenerative brake BR is used as a braking device, and power is generated during braking (strictly speaking, kinetic energy is converted into electrical energy), and the generated electricity can be charged into a battery (not shown). Therefore, energy efficiency is improved compared to a case where kinetic energy is dissipated as thermal energy using a friction brake. In the embodiment, the load and pulsation are judged using the current value of the PTO motor M1, but this is not limited to this. For example, the judgment can be made based on the fluctuation of the angular velocity of the output shaft of the PTO motor M1, or based on the vibration (acceleration) of the seedling planting tool 41, or based on any other parameter.

[0049] In addition, the timing of applying the regenerative brake BR is preferably immediate when an excessive load is detected, but is not limited to this. If vibration (pulsation) is observed to be occurring in a member other than the PTO motor M1 (such as the frame of the seedling planting device 3), applying the brake may cause further pulsation, so it is possible to apply the brake at a later time until the vibration of the frame of the seedling planting device 3 and the like subsides to some extent.

[0050] Furthermore, when the planting control means 309A of the embodiment drives the PTO motor M1 according to the planting position of the seedling, it determines (calculates) the phase (target phase, target position) of the PTO motor M1 at the planting position of the next seedling from the rotation amount (rotation angle) of the PTO motor M1 corresponding to the distance to the planting position of the next seedling based on the phase (current phase) of the PTO motor M1 at the current position, and drives the PTO motor M1 based on the target phase. Here, the target phase may be in a negative position with respect to the rotation direction of the PTO motor M1 with respect to the current phase due to an erroneous calculation of the target phase due to a detection error of the current position, the motor output shaft overshooting due to the load, or erroneous detection of the motor phase sensor SN3. If the target phase is in a negative position with respect to the current phase, there is a risk that the PTO motor M1 will rotate in the reverse direction. If the PTO motor M1 rotates in the reverse direction, there is a risk of failure or damage if the members such as the seedling planting tool 41 do not support reverse rotation. Therefore, in this embodiment, when the target phase is in a negative position with respect to the current phase, the current phase is used as the target phase and correction is performed so as not to reverse the phase.

[0051] The lifting control means 309B controls the lift cylinder 36 to lift and lower the seedling planting device 3. When automatic travel is started, the lifting control means 309B in the embodiment lowers the seedling planting device 3 when it reaches the work start position or the turning end position on the work route, and raises the seedling planting device 3 when it reaches the turning start position or the work end position. While the seedling planting device 3 is lowered and planting work is being performed, the lifting control means 309B controls the seedling planting device 3 to be raised and lowered so that the position of the center float 42 relative to the field scene is a predetermined position, that is, the height of the seedling planting tool 41 relative to the field scene is a constant height, based on the detection result of the float sensor SN4. That is, when the height of the seedling planting tool 41 relative to the field scene becomes too low, the seedling planting device 3 is raised, and when the height of the seedling planting tool 41 relative to the field scene becomes too high, the seedling planting device 3 is lowered. In other words, the lifting control means 3 controls the seedling planting device 3 to be raised and lowered so that the angle detected by the float sensor SN4 is within a predetermined range. Therefore, by maintaining a constant height of the seedling planting tool 41 relative to the field, the planting depth of the seedlings relative to the field is maintained constant.

[0052] The planting depth control means 309C controls the planting depth of the seedlings planted in the field via the planting depth adjustment motor M2 as an example of the second drive source. In the planting depth control means 309C of the embodiment, the center float 42 is configured to be movable up and down via an arm (not shown, see the arm 43a of the side float 43 in FIG. 1, which has a similar configuration) relative to the frame 3a of the seedling planting device 3. The arm is rotated and moved by the planting depth adjustment motor M2, so that the distance between the center float 42 and the frame of the seedling planting device 3, that is, the height of the center float 42 relative to the seedling planting tool 41, can be adjusted. If the center float 42 is lowered to widen the distance from the seedling planting tool 41, the distance of the seedling planting tool 41 relative to the field surface becomes longer when the center float 42 touches the field surface. Therefore, when planting seedlings with the seedling planting tool 41, the seedling planting tool 41 penetrates less deeply into the soil than the field surface, resulting in a shallower planting depth. Conversely, if the center float 42 is raised to narrow the distance to the seedling planting tool 41, the distance of the seedling planting tool 41 to the field surface when the center float 42 touches the field surface becomes shorter, resulting in a deeper planting depth.

[0053] The planting depth control means 309C adjusts the planting depth by driving the planting depth adjustment motor M2 in response to the operator's input through the planting depth switch SW1. In the embodiment, the planting depth control means 309C stops the operation of the planting depth adjustment motor M2 and changes the planting depth when an input to change the planting depth is made through the planting depth switch SW1 based on the detection result of the float sensor SN4 if the grounding of the center float 42 is not detected. In other words, when the seedling planting device 3 is raised while stopped or turning, and the center float 42 is separated from the field, the planting depth is changed in response to the input when the planting depth switch SW1 is operated.

[0054] On the other hand, the planting depth control means 309C of the embodiment stops (does not operate) the planting depth adjustment motor M2 when the grounding of the center float 42 is detected based on the detection result of the float sensor SN4, even if an input to change the planting depth is made with the planting depth switch SW1. This is because, when the planting depth is changed with the center float 42 in the grounded state, an unexpected load may be generated on the center float 42 and the planting depth adjustment motor M2, which may damage the center float 42, etc. Therefore, in the embodiment, when the center float 42 is in the grounded state, the planting depth adjustment motor M2 is not operated even if an input to change the planting depth is made, thereby suppressing damage to the components.

[0055] In the planting depth control means 309C of the embodiment, if the planting depth switch SW1 is operated while the center float 42 is in the ground during operation, the planting depth adjustment motor M2 is not operated, but if the seedling planting device 3 subsequently rises due to rotation or the like and the center float 42 is no longer in the ground, the planting depth adjustment motor M2 is operated according to the input of the planting depth switch SW1 at that time to change the planting depth. Therefore, since the planting depth is changed while the center float 42 is away from the field surface, there is little risk of damage to parts.

[0056] In addition, when the planting depth control means 309C of the embodiment detects the grounding of the center float 42 and an input to change the planting depth is made with the planting depth switch SW1, the planting depth control means 309C displays on the touch panel 101, which is an example of a display device, that the planting depth will not be changed. The content to be displayed is not limited to a simple display such as "The planting depth cannot be changed." For example, it is preferable to display a display on the touch panel 101 to indicate a situation in which the planting depth can be changed, such as "Please raise the seedling planting device to change the planting depth." In the embodiment, the embodiment shows an example of a mode in which the operator is notified by displaying on the touch panel 101, but is not limited to this. For example, the notification method can be changed to any method such as voice guidance, lighting of a lamp, or an alarm sound such as a buzzer. It is preferable to notify the operator by display, but it is also possible to configure the system so that no notification is made. In other words, since the planting depth will be changed when the center float 42 moves away from the field scene during the next turn, etc., it is possible to configure the system so that no notification is made if there is a risk that the operator will be confused if a notification is made.

[0057] In addition, the embodiment has been described in which the planting depth adjustment motor M2 is not operated even if an input to change the planting depth is made with the planting depth switch SW1 when the grounding of the center float 42 is detected, but the present invention is not limited to this. For example, it is possible to control the planting depth adjustment motor M2 not to operate when an input to make the planting depth shallow is made, but to operate the planting depth adjustment motor M2 when an input to make the planting depth deep is made. When making the planting depth shallow, the center float 42 is pressed against the field surface, and the load on the planting depth adjustment motor M2 is also large, so it is desirable to control the planting depth adjustment motor M2 not to operate in order to prevent damage. On the other hand, when making the planting depth deep, the center float 42 is moved in a direction away from the field surface, which reduces the force received by the center float 42 and reduces the load on the planting depth adjustment motor M2, so it is possible to operate the planting depth adjustment motor M2 to change the planting depth.

[0058] The ground leveling rotor control means 309D controls the rotor motor M3 and the rotor lifting motor M4 to rotate the ground leveling rotors 70a, 70b at a predetermined height. The ground leveling rotor control means 309D in this embodiment rotates the ground leveling rotors 70a, 70b at a predetermined rotation speed according to the speed of the traveling vehicle body 1, and holds the ground leveling rotors 70a, 70b at a predetermined height. In addition, in the embodiment, the leveling rotor control means 309D controls the rotor motor M3 to control the rotation speed and change it to a rotation that results in a low load when the load reaches a predetermined load (threshold) based on the detection result of the rotor load sensor SN5.

[0059] For example, when the load is higher than the threshold, the rotation speed is first increased, and when the load falls below the threshold, the ground leveling rotors 70a, 70b are rotated at the increased rotation speed. When the load increases as the rotation speed is increased, the rotation speed is reduced, and when the load falls below the threshold, the ground leveling rotors 70a, 70b are rotated at the reduced rotation speed. That is, if the ground speed (vehicle speed) of the ground leveling rotors 70a, 70b and the rotation of the ground leveling rotors 70a, 70b are not aligned, the load may become excessive. Therefore, by adjusting the rotation of the ground leveling rotors 70a, 70b, the load on the rotor motor M3 can be reduced and the ground leveling can be stabilized. The ground speed can be calculated using the GNSS from the detection result of the position acquisition means 301, or can be calculated taking the slip ratio into consideration.

[0060] In particular, in the conventional configuration where drive is received from the rear wheel transmission case 24, rotation is transmitted in conjunction with the rotation speed of the rear wheels 7, so the rotation speed of the ground leveling rotors 70a, 70b cannot be changed and it is prone to overload. In contrast, in the embodiment, rotor motor M3 is used for the ground leveling rotors 70a, 70b, and rotor motor M3 can adjust the speed of the ground leveling rotors 70a, 70b to a rotation speed that places less load, making ground leveling more stable.

[0061] If the load does not fall below the threshold value even when the speed is increased or decreased, it is determined that the ground leveling rotors 70a, 70b are likely to have sunk into the soil, and the rotor lifting motor M4 is operated to raise the ground leveling rotors 70a, 70b until the load falls below the threshold value. In this way, by changing the rotation speed and height according to the load, it is possible to further reduce the load on the rotor motor M3 and stabilize the ground leveling.

[0062] It is also possible to estimate the weight of the soil in the field (hardness or softness of the soil) based on the load current of the rotor motor M3 and reflect this in the control. For example, when the soil is heavy (soft), the rotation speed of the soil leveling rotors 70a, 70b can be increased, and when the soil is light, the rotation speed of the soil leveling rotors 70a, 70b can be decreased. It is also possible to automatically adjust the hydraulic pressure according to the weight of the soil in the field, and to automatically adjust the amount of steering adjustment during automatic driving during work (the amount of fine adjustment of the steering wheel 16 when traveling straight).

[0063] In addition, the rotation of the soil leveling rotors 70a, 70b can be controlled differently during work and during turning. For example, an inner / outer wheel difference occurs during turning. Here, if the rotation of the soil leveling rotors 70a, 70b is set based on the inner wheel side, the ground speed of the soil leveling rotors 70a, 70b will be slow on the outer wheel side, and there is a risk that the soil leveling rotors 70a, 70b will push the mud on the field surface. Therefore, during turning, it is possible to set the rotation of the soil leveling rotors 70a, 70b based on the ground speed of the outer wheel side. On the other hand, if the rotation of the soil leveling rotors 70a, 70b is set based on the outer wheel side, the ground speed of the soil leveling rotors 70a, 70b will be fast on the inner wheel side, and there is a risk that the soil leveling rotors 70a, 70b will dig up the field. Therefore, during turning, it is also possible to set the rotation of the soil leveling rotors 70a, 70b based on the ground speed of the inner wheel side.

[0064] In the seedling transplanter of the embodiment having the above configuration, when planting work is performed, if the current position is acquired by the position acquisition means 301, that is, if the current position can be acquired by GNSS, the seedlings are planted based on the GNSS, and if the GNSS is lost or in an error state, the seedlings are planted based on the rotation speed of the rear wheels 7. Therefore, even if the GNSS is lost, etc., it is possible to continue planting based on the rotation speed of the rear wheels 7, and planting can be performed with high accuracy even if the current position cannot be acquired.

[0065] (Example of change) The work vehicle of the present invention is not limited to a rice planter, but can also be applied to a seedling transplanter that transplants vegetable seedlings. Also, although a rice planter that uses so-called mat-shaped seedlings has been exemplified, the work vehicle is not limited to this, and can also be applied to a rice planter that uses pot-shaped seedlings. Furthermore, although a riding seedling transplanter has been illustrated, the present invention is not limited to this and can also be applied to an autonomously driven work vehicle.

[0066] In addition, although the above embodiment shows a configuration in which all the processes of the means 301 to 309 are centralized in the seedling transplanter, the present invention is not limited to this. It is also possible to provide one or more of the means 301 to 309 in a server or computer device connected by a communication line, and perform distributed processing.

[0067] Furthermore, in the embodiment, a configuration has been exemplified in which control is performed taking into account the occurrence of slippage, but if a configuration is adopted in which slippage is less likely to occur, it is also possible to have a configuration that does not take into account the occurrence of slippage. As a configuration for preventing slippage, for example, sensors for detecting the rotation speed and torque are provided on the left and right axles of the front wheels 6 and the rear wheels 7, and when slippage is likely to occur (for example, when the rotation speed is about to reach a threshold value), the left and right axles with the higher rotation speed are braked to maintain the drive torque and suppress the occurrence of slippage. Here, when braking, it is possible to use an alternator (generator) to generate electricity while braking (power generation places a load on the rotation = braking is applied). When using an alternator, it is also possible to generate electricity when traveling at low speeds and not generate electricity when traveling at high speeds. Since there is a tendency for the amount of power generation to be insufficient when traveling at low speeds and precise behavior is required when traveling at low speeds compared to when traveling at high speeds, it is possible to generate electricity while stabilizing behavior by using the alternator to generate power and brake at low speeds. The alternator can change the load resistance (braking capacity) by increasing or decreasing the current flowing through the electromagnet of the rotor to increase or decrease the magnetic force. Therefore, when starting the engine, the load resistance of the alternator can be minimized to improve starting performance, and when braking to stop the traveling vehicle body 1 at the end of the work position or during an emergency stop, the load resistance of the alternator can be maximized to support braking, thereby generating electricity and shortening the braking distance. [Explanation of symbols]

[0068] 1...Traveling vehicle, 3...planting device, 7...wheels, 42…Float, 101...Indicator, 300...control unit, 301...position acquisition means, 302...rotation speed detection means, 305...load detection means, BR…Regenerative braking device, L0: second travel distance, L1: First travel distance, L1 / L0: slip ratio, M1: Driving source, M2: second drive source, SW1...Input component.

Claims

1. A traveling vehicle body (1) having a traveling device (7), a planting device (3) supported by the traveling vehicle body (1) and configured to plant seedlings in a field; A position acquisition means (301) for acquiring a current position of the traveling vehicle body (1); A drive source (M1) for driving the planting device (3); A rotation speed detection means (302) for detecting the rotation speed of the traveling device (7); a control unit (300) that controls the planting device (3) via the drive source (M1) to plant seedlings at a predetermined position, the control unit (300) driving the drive source (M1) based on the acquisition result of the position acquisition means (301) when a current position is acquired by the position acquisition means (301), and driving the drive source (M1) based on the detection result of the number of rotations of the number of rotations detection means (302) when a current position is not acquired by the position acquisition means (301); A work vehicle comprising:

2. the control unit (300) calculating a slip ratio (L1 / L0) which is a ratio of the first moving distance (L1) to the second moving distance (L0) based on a first moving distance (L1) based on a transition of the current position acquired by the position acquisition means (301) and a second moving distance (L0) based on the number of rotations of the traveling device (7) detected by the number of rotations detection means (302), and controlling the driving source (M1) using the slip ratio (L1 / L0) when driving the driving source (M1) based on the detection result of the number of rotations of the number of rotations detection means (302); The work vehicle according to claim 1, further comprising:

3. A regenerative braking device (BR) that brakes the planting device (3) and generates electricity when braking; A load detection means (305) for detecting a load of the driving source (M1); the control unit (300) for controlling the regenerative braking device (BR) to brake the planting device (3) when a load exceeding a predetermined load is detected based on a detection result of the load detection means (305); The work vehicle according to claim 2, further comprising:

4. the control unit (300) setting the current phase as the target phase when a target phase of the rotation direction of the drive source (M1) determined based on the current position acquired by the position acquisition means (301) is in a negative position with respect to a current phase of the drive source when the rotation direction of the drive source (M1) is set to a positive direction during planting; The work vehicle according to claim 1, further comprising:

5. A second drive source (M2) for changing a planting depth, which is a depth at which seedlings are planted in a field by the planting device (3); An input member (SW1) through which the operator inputs the planting depth; A float (42) provided in the planting device (3) for detecting the state of the field when the float comes into contact with and separates from the field; The control unit (300) stops the operation of the second driving source (M2) when the float (42) is grounded, even if an input to change the planting depth is input; The work vehicle according to claim 1, further comprising:

6. the control unit (300) that stops the operation of the second driving source (M2) when an input to reduce the planting depth is input upon detecting the grounding of the float (42); The work vehicle according to claim 5, further comprising:

7. the control unit (300) displaying on a display (101) that the planting depth will not be changed if an input to change the planting depth is made when the control unit (300) detects the grounding of the float (42); 6. The work vehicle according to claim 5, further comprising:

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