Work vehicle

Abstract

To provide a work vehicle that allows a finishing state of a tilled field to be checked without depending on visual recognition of a farm field, and allows insufficient tilling to be noticed quickly.SOLUTION: A work vehicle 1 equipped with a work machine 3 for tilling a farm field includes an optical imaging device LD for imaging the farm field, and a control part C for acquiring three-dimensional imaging information indicating a shape of the farm field from the optical imaging device LD. The optical imaging device LD is configured so as to scan the farm field after tilling linearly and image the farm field. The control part C calculates a farm field height line Ln1, which is a line segment indicating a height of the farm field top face from the acquired three-dimensional imaging information, evaluates whether a vertical width of the calculated farm field heigh line falls within a predetermined range, and outputs the evaluation result from an output part 245.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a work vehicle for cultivating farm fields. [Background technology]

[0002] Conventionally, a work vehicle equipped with a tiller for cultivating a field has been known as a working machine (see, for example, Patent Document 1). This conventional work vehicle is configured to cultivate the field with a working machine disposed at the rear of the traveling vehicle body while a worker rides on the vehicle and travels through the field. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2023-48296 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, with conventional work vehicles, the worker must visually check the field to see how the tillage has been completed, which is inconvenient. In addition, when the worker is in the work vehicle, he or she faces forward, and the work machine runs behind the work vehicle while tilling, so it is difficult to notice when the tillage is insufficient, and there is a risk that the delay in discovering insufficient tillage will lead to a significant decrease in work efficiency.

[0005] The present invention has been made in consideration of the above, and aims to provide a work vehicle that enables a worker to check the state of tillage completion without visually inspecting the field and to quickly notice when tillage is insufficient, thereby improving work efficiency. [Means for solving the problem]

[0006] In order to solve the above problems and achieve the object, the first invention provides: A work vehicle equipped with a work machine for cultivating a field, an optical imaging device that captures an image of a farm field; and a control unit that acquires three-dimensional imaging information indicating a shape of the farm field from the optical imaging device, The optical imaging device is configured to linearly scan and image a cultivated field, The control unit calculates a field elevation line, which is a line segment indicating the elevation of the top surface of the field, from the acquired three-dimensional imaging information, evaluates whether the top and bottom widths of the calculated field elevation line fall within a specified range, and provides a work vehicle characterized in that it is configured to output the evaluation result from an output unit.

[0007] According to the first invention described above, the worker can check the finished state of the field after tilling by looking at the output from the output unit without visually inspecting it, and furthermore, can quickly notice when the tilling is insufficient, thereby improving the accuracy of tilling, improving convenience for the worker, and improving work efficiency.

[0008] A second invention is, in addition to the configuration of the first invention, the work vehicle is provided with a rolling mechanism for rotating the work implement, and the control unit controls the rolling mechanism to enable rolling control of the work implement, The control unit calculates a tillage surface inclination line indicating the inclination of the top surface of the field after tilling by approximating the calculated field elevation line with a straight line, and calculates a tillage surface inclination angle which is the angle between the calculated tillage surface inclination line and a line segment indicating the horizontal direction of the field; The rolling control is characterized in that the posture of the work implement is corrected so as to achieve a rotation direction and angle that cancels out the calculated tillage surface inclination angle.

[0009] According to the second invention, in addition to the effects of the first invention, the rolling posture of the working machine can be corrected (modified) based on the actual inclination of the top surface of the field after cultivation, so that the field can be made level even if the finished field scene after cultivation is inclined under normal rolling control. As a result, the finished field scene after cultivation can be made well level, and the quality of the cultivation work can be improved significantly.

[0010] The third invention has the same configuration as the first invention, as well as: The control device is characterized in that it is configured to calculate an average horizontal elevation line, which is a horizontal line indicating the average height of the field elevation line, from the calculated field elevation line, and to output instruction information from an output unit urging the operator to slow down the vehicle speed if the difference between the height indicated by the calculated average horizontal elevation line and a preset target height exceeds a predetermined limit value.

[0011] According to the third aspect of the present invention, in addition to the effects of the first aspect of the present invention, the quality of tilling work performed by the implement on the tilled field can be appropriately evaluated. The operator can effectively prevent insufficient tilling by reducing the vehicle speed based on the instruction information. Effect of the Invention

[0012] According to the present invention, a work vehicle can be provided that enables an operator to check the state of tillage completion without visually inspecting the field, and quickly become aware when tillage is insufficient. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a side view showing an example of a work vehicle according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a rear view of a main portion of the work vehicle of FIG. [Diagram 3] FIG. 3 is a block diagram showing the input / output configuration of the control unit C. [Figure 4] FIG. 4 is a diagram showing an example of the hydraulic circuit 50 of FIG. [Diagram 5]FIG. 5 is a view showing part A in FIG. 4, illustrating the oil supply amount adjusting section. [Figure 6] FIG. 6 is an explanatory diagram for explaining an example of an illumination range of the optical imaging device. [Figure 7] FIG. 7 is a diagram showing an example of tillage information generated by the control unit in the evaluation of tillage conditions (method 1). [Figure 8] FIG. 8 is a diagram showing an example of tillage information generated by the control unit in the evaluation of the tillage state (method 2). [Figure 9] FIG. 9 is a diagram showing an example of tilling information generated by the control unit in rolling control of the work machine based on three-dimensional imaging information. [Figure 10] FIG. 10 is a schematic rear view of the work vehicle for explaining rolling control of the work implement based on tilling information. [Figure 11] FIG. 11 is a diagram showing an example of tillage information generated by the control unit regarding control related to recording the positions of depressions in a farm field. [Figure 12] FIG. 12 is an image diagram of a 3D image generated in relation to the control relating to the generation of a 3D image of the top surface of a tilled farm field. [Figure 13] FIG. 13 is a diagram showing an example of tillage information generated by the control unit in the determination control of residual tillage based on three-dimensional imaging information. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a work vehicle disclosed in the present application will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiment described below.

[0015] <1. Overview of work vehicle (tractor)> First, an overview of a work vehicle 1 according to a preferred embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a side view showing an example of a work vehicle 1 according to an embodiment of the present invention.

[0016] 1 shows a three-dimensional Cartesian coordinate system including a Z-axis with the positive direction being vertically upward (upward). In the following description, the positive direction of the X-axis is defined as the left, the negative direction of the X-axis is defined as the right, the positive direction of the Y-axis is defined as the front, and the negative direction of the Y-axis is defined as the rear with respect to the work vehicle 1, and the X-axis direction is defined as the left-right direction, the Y-axis direction as the front-rear direction, and the Z-axis direction as the up-down direction, but the definitions of these directions themselves are not intended to limit the invention.

[0017] As shown in FIG. 1, the work vehicle 1 is, for example, an agricultural tractor (hereinafter simply referred to as "tractor") 1 that works in a farm field, and is equipped with a traveling body 2 and a working implement 3. The traveling body 2 is a vehicle body equipped with a traveling device and configured to be able to travel within a farm field. As the traveling device, a pair of left and right front wheels 21 and a pair of left and right rear wheels 22 are equipped. The front wheels 21 are steered wheels, and the rear wheels 22 are driven wheels. Note that hereinafter, the tractor 1 and the traveling body 2 may be referred to as "machine body".

[0018] The rear wheels 22 are configured to be capable of transmitting power generated by an engine E mounted inside a bonnet 23 of the traveling vehicle body 2, for example, at an appropriate reduced speed in a main transmission and an auxiliary transmission (neither of which are shown in the figures). In other words, the rear wheels 22 are driven by the power transmitted from the engine E.

[0019] The tractor 1 may be configured so that the power generated by the engine E and reduced in speed by the main transmission and the sub transmission is also transmitted to the front wheels 21 via a front wheel speed increasing switching mechanism (not shown) to drive four wheels, that is, the left and right front wheels 21 and the left and right rear wheels 22. Also, the tractor 1 may be configured so that it is possible to switch between two-wheel drive and four-wheel drive.

[0020] 1, the traveling vehicle body 2 includes a control section 24. The control section 24 includes a cockpit 241, a steering wheel 242, and various other operating devices (such as a clutch pedal, a brake pedal, an accelerator pedal, a main shift lever, an auxiliary shift lever, a lift switch 243, and a position lever 244).

[0021] The cockpit 241 is a seat where a pilot (also called an operator) of the aircraft sits. The steering wheel 242 is an operating tool for steering the front wheels 21, which are steering wheels. In front of the steering wheel 242, an image and audio output unit 245 equipped with a liquid crystal panel and a speaker, a meter panel, and the like are provided. In addition, an arch-shaped safety bar (ROPS) 25 is provided behind the control unit 24 when viewed from the front of the aircraft. In addition, the control unit 24 may be covered by a cabin. In addition, the image and audio output unit 245 functions as an output unit that outputs various information. In addition, instead of the image and audio output unit 245, an information terminal (for example, a tablet or a smartphone) that is provided so as to be able to communicate with the control unit C described later may be configured to output images and sounds that the image and audio output unit 245 should output.

[0022] The lift switch 243 is a switch that is operated when raising or lowering the work machine 3. The position lever 244, like the lift switch 243, is a lever that is operated when raising or lowering the work machine 3.

[0023] The position lever 244 can raise and lower the working machine 3 by changing the lifting speed depending on the amount of operation by the operator. For example, when the position lever 244 is operated to a large extent, the working machine 3 can be raised and lowered at a higher speed, and when the position lever 244 is operated to a small extent, the working machine 3 can be raised and lowered at a lower speed. The operator raises and lowers the working machine 3 by operating either the lift switch 243 or the position lever 244.

[0024] The work machine 3 is a rotary tiller that tills farm fields, and includes tillage tines 31 and a rotary cover 32. The tillage tines 31 receive power from a PTO shaft 26 (see FIG. 2) to rotate and till the soil. The rotary cover 32 is provided to cover the tillage tines 31 from above.

[0025] Further, an optical imaging device LD for imaging the field is attached to the working machine 3. The attachment position is, for example, approximately the center in the left-right direction of the upper part of the working machine 3. The optical imaging device LD is a 3D lidar, and obtains three-dimensional imaging information (3D image data) by irradiating an optical radar that emits pulsed light on a target and capturing scattered light, and is capable of detecting the distance and shape of an object present in the irradiation range (scanning range or imaging range) of the optical radar by analyzing the obtained three-dimensional imaging information. This allows the optical imaging device LD to obtain three-dimensional imaging information indicating the shape of the field in the irradiation range. The three-dimensional imaging information obtained by the optical imaging device LD is transmitted to a control unit C described later.

[0026] The tractor 1 is equipped with a lifting mechanism 4A that lifts and lowers the working implement 3, and a rolling mechanism 4B that rolls the working implement 3. The tractor 1 further includes a control unit C that controls the lifting mechanism 4A and the rolling mechanism 4B. Next, the lifting mechanism 4A and the rolling mechanism 4B will be described in detail.

[0027] <Configuration of lifting mechanism for work equipment> The lifting device 4A includes a lift arm 41, a lower link 42, a lift rod 43, and a main cylinder 44. The lift arm 41 rotates (swings) in the vertical direction about a rotation shaft 411 by a driving force from the main cylinder 44 described later. The lower link 42 is disposed below the lift arm 41, and a rear end portion thereof is connected to the work machine 3. The lift rod 43 is provided between the lift arm 41 and the lower link 42, and connects the lift arm 41 and the lower link 42.

[0028] A lift arm angle sensor 412 such as a potentiometer is provided near the rotation shaft 411 of the lift arm 41 to detect the rotation angle of the lift arm 41. The height of the work machine 3 is calculated in a control unit C (see FIG. 2) described later based on the detection value of the lift arm angle sensor 412.

[0029] The main cylinder 44 is connected to the lift arm 41 and applies hydraulic driving force to the lift arm 41. The main cylinder 44 includes a hydraulic cylinder 441 and a rod 442. The hydraulic cylinder 441 drives the rod 442 when hydraulic oil is supplied from a hydraulic circuit 5 (see FIG. 3) described later or when hydraulic oil is discharged to the hydraulic circuit. The rod 442 is connected to the front end side of the lift arm 41.

[0030] When hydraulic oil is supplied to the hydraulic cylinder 441, the main cylinder 44 drives the lift arm 41 via the rod 442 to lift the work machine 3. When hydraulic oil is discharged from the hydraulic cylinder 441, the main cylinder 44 drives the lift arm 41 via the rod 442 to lower the work machine 3.

[0031] <Rolling mechanism for work equipment> Next, the rolling mechanism of the work implement 3 will be described with reference to Fig. 2. Fig. 2 is a rear view of the main parts of the work vehicle 1.

[0032] As shown in FIG. 2, the rolling mechanism 4B includes a PTO coupling device 27 that can be attached to the work machine 3 by connecting the PTO shaft 26, and a rolling cylinder 431 that rotates (rolls) the work machine 3 attached to the PTO coupling device 27.

[0033] The PTO coupling device 27 is provided at the rear of the tractor 1, and is a device that allows the work implement 3 to be attached and detached, and is equipped with a work implement support member 27a that supports the work implement 3 and tilts (rotates) left and right with the rolling of the work implement 3, and a PTO shaft 26. As a result, the work implement 3 attached to the PTO coupling device 27 is rotatable with respect to the traveling vehicle body 2, and is driven by receiving power from the engine E through the connecting pivot PTO shaft 26. In addition, a PTO shaft cover 28 is fixed to the upper part of the work implement support member 27a.

[0034] The rolling cylinder 431 is a double-acting hydraulic cylinder provided on the lift rod 43, and is configured so that the extension and contraction of the cylinder 431 raises and lowers either the left or right side of the work machine 3. As a result, in order to rotate (roll) the work machine 3, the control unit C controls the extension and contraction of the rolling cylinder 431, thereby enabling control to keep the work machine 3 in a horizontal position (horizontal control).

[0035] The inclination angle detection device S1 is provided at the rear of the traveling body 2 and behind the driver's seat 241, and is configured to include an inclination sensor that detects the inclination angle of the traveling body 2 with respect to the horizontal direction (more specifically, the inclination angle in the left-right direction around the roll axis of the traveling body 2). Information on the detected inclination angle of the traveling body 2 is transmitted by this inclination angle detection device S1 to the control unit C. This enables the control unit C to control the extension and contraction of the rolling cylinder 431 based on the detection value of the inclination sensor, thereby controlling the rolling posture of the work machine 3. The control unit C is provided at a position close to and below the inclination sensor at the rear of the traveling body 2.

[0036] A roll angle detection device S2 that detects the attitude (rolling attitude) of the work machine 3, i.e., the roll angle in the left-right direction relative to the traveling vehicle body 2, is provided below the control unit C in the vicinity of the control unit C. This roll angle detection device S2 is configured to include a stroke sensor s21. When the work machine support member 27a rotates in the left-right direction as the work machine 3 rolls, the work machine support member 27a also rotates in the same manner. Here, when the work machine support member 27a rotates, the rotating arm s23 connected to the connecting rod s22 rotates about the rotating shaft s24 as a fulcrum. Then, the stroke sensor s21 detects the amount of change (amount of rotation) of the rotating arm s23 to detect the rolling attitude (roll angle) of the work machine 3. As a result, the control unit C is able to calculate the inclination control amount of the work machine 3 (the control amount when controlling the work machine 3 to have a predetermined inclination angle relative to the horizontal direction) by comparing the detection value (inclination angle) of the inclination angle detection device S1 with the detection value (roll angle) of the inclination angle detection device S2.

[0037] <Control unit input / output configuration> FIG. 3 is a block diagram showing the input / output configuration of the control unit C. The control unit C is an information processing device configured by combining a plurality of ECUs (Electronic Control Units).

[0038] As shown in FIG. 3, the control unit C has an input side connected to a lift switch 243, a position lever 244, a lift arm angle sensor 412, a tilt angle detection device S1, a roll angle detection device S2, an optical imaging device LD, etc., and is capable of acquiring various information such as detection information and operation information from these sensors and devices.

[0039] Moreover, the control unit C is connected on the output side to the hydraulic circuit 50 and the image / audio output unit 245, and is capable of controlling the extension and contraction of the main cylinder 44 and the rolling cylinder 431 via the hydraulic circuit 50. Moreover, by transmitting image information and audio information to the image / audio output unit 245 to output images and audio, it is possible to notify the worker of various information as necessary.

[0040] As a result, the control unit C outputs signals to each part of the hydraulic circuit 50 (described later) to raise or lower the work machine 3 (see FIG. 1) based on the operator's operation of the lift switch 243 and the position lever 244. In addition, the control unit C performs depth control and decelerator control (described later) based on the detection value of the lift arm angle sensor 412.

[0041] The hydraulic circuit 50 also includes a pump 51 that supplies hydraulic oil, and an oil passage 52 through which the hydraulic oil supplied from the pump 51 flows. The hydraulic circuit 50 is a circuit for supplying or discharging hydraulic oil to or from the main cylinder 44 and the rolling cylinder 431.

[0042] The control unit C changes the height of the working machine 3 by driving the lift arm 41 based on the detection value of a tillage depth sensor (not shown), and maintains the tillage depth at a set value. Specifically, when the working machine 3 is lifted above a predetermined position, the control unit C determines that the tillage depth is deeper than the set value and moves the working machine 3 upward. When the working machine 3 is positioned below a predetermined position, the control unit C determines that the tillage depth is shallower than the set value and moves the working machine 3 downward. Such vertical movement of the working machine 3 is performed based on the rotation angle of the lift arm 41, i.e., the detection value of the lift arm angle sensor 412. Such control to maintain the tillage depth at a set value is called "depth control."

[0043] In addition, when the work implement 3 descends and touches the ground, such a tractor 1 performs so-called "deceleration control" that reduces the descent speed of the work implement 3 near the ground to prevent shocks such as large shaking of the machine body due to the work implement 3 touching the ground, and to prevent the machine body from suddenly moving forward (dashing) due to the work implement 3 having rotating tiller tines 31 (see Figure 1) like a rotary tiller touching the ground.

[0044] <Hydraulic circuit configuration> Next, the hydraulic circuit 50 in Fig. 3 will be described with reference to Fig. 4 and Fig. 5. Fig. 4 is a diagram showing an example of the hydraulic circuit 50 in Fig. 3. Fig. 5 is a diagram showing part A in Fig. 4, which is a diagram showing the oil supply amount adjustment unit 54.

[0045] As shown in FIG. 3, the hydraulic circuit 50 has an oil passage 52 that supplies hydraulic oil from a main pump 511 of the pumps 51 to the traveling valve, the traveling clutch, the main relief, the flow dividing valve, the horizontal valve, the hydraulic cylinder (rolling cylinder) 431, the main control valve 53, the oil supply amount adjustment section 54, the slow return 55, the decelerator valve 56, the main cylinder 44, etc.

[0046] The hydraulic oil from the main pump 511 is adjusted in pressure (hydraulic pressure) by the main relief valve and supplied to the traveling clutch to control the traveling clutch. The hydraulic oil diverted by the diverter valve is supplied to the rolling cylinder 431 and the main cylinder 44 to control the working machine 3 (see FIG. 1).

[0047] The hydraulic circuit 50 also has an oil passage 52 that supplies hydraulic oil from a sub-pump 512 of the pump 51 to a power steering system, a relief valve, an oil cooler, a charge filter, a hydrostatic transmission (HST), a neutral valve, etc.

[0048] The hydraulic oil from the sub pump 512 is supplied to the power steering, passes through a relief valve and an oil cooler, and is then supplied to the HST.

[0049] 3 and 4, the oil supply amount adjustment unit 54 described above is disposed downstream of the main control valve 53 to which hydraulic oil is supplied from the main pump 511. The oil supply amount adjustment unit 54 is provided to perform decelerator control even when the work machine 3 (see FIG. 1) is rising. When the work machine 3 is raised at a predetermined speed or faster, the oil supply amount adjustment unit 54 reduces the amount of hydraulic oil supplied to the main cylinder 44 so as to gradually slow down the rising speed of the work machine 3 as the rising work machine 3 approaches the top end point (the highest position of the work machine 3).

[0050] As shown in Fig. 4, hydraulic oil O supplied from main pump 511 (see Fig. 3) passes through main control valve 53 and is supplied to oil supply amount adjustment section 54. The amount of hydraulic oil O supplied from main control valve 53 is adjusted according to the amount of operation of position lever 244 (see Fig. 1) by the operator.

[0051] Moreover, the hydraulic oil O passes from the oil supply amount adjusting section 54 through the slow return 55 and the decelerator valve 56 and is supplied to the main cylinder 44.

[0052] 4, the oil supply amount adjusting unit 54 includes a throttle valve 541, a directional control valve 542, a pressure compensation valve 543, a piping volume 544, a variable throttle valve 545, and a switchable throttle valve 546. The oil supply amount adjusting unit 54 also includes a first oil passage 521 and a second oil passage 522 that are switched by a directional control valve 542 described later.

[0053] The throttle valve 541 generates a differential pressure according to the amount of hydraulic oil O per unit time supplied from the main control valve 53 by adjusting the diameter of the oil passage 52. For example, when the pilot operates the position lever 244 greatly (for example, to the maximum), the amount of hydraulic oil O per unit time supplied to the throttle valve 541 increases, causing the throttle valve 541 to generate a differential pressure before and after it (between the upstream and downstream sides).

[0054] The directional control valve 542 switches the supply direction of the hydraulic oil O supplied from the throttle valve 541, i.e., whether to supply the hydraulic oil O to the first oil passage 521 or to the second oil passage 522. The directional control valve 542 supplies the hydraulic oil O to the first oil passage 521 when the differential pressure is equal to or lower than a predetermined value. The directional control valve 542 supplies the hydraulic oil O to the second oil passage 522 when the differential pressure is equal to or higher than a predetermined value.

[0055] That is, the first oil passage 521 is an oil passage through which the hydraulic oil O supplied from the directional control valve 542 flows when the throttle valve 541 does not generate a pressure difference equal to or greater than a predetermined pressure difference. The second oil passage 522 is an oil passage through which the hydraulic oil O supplied from the directional control valve 542 flows when the throttle valve 541 generates a pressure difference equal to or greater than a predetermined pressure difference.

[0056] In addition, in the directional control valve 542, when hydraulic oil O is supplied to the second oil passage 522, not all of the hydraulic oil O is supplied to the second oil passage 522, but some is supplied to the first oil passage 521 while also being supplied to the second oil passage 522, so that the work machine 3 can continue to rise.

[0057] Pressure compensating valve 543 is disposed in second oil passage 522. Pressure compensating valve 543 rectifies the hydraulic oil O flowing through second oil passage 522 to make the pressure constant. Piping volume 544 is disposed in second oil passage 522. Piping volume 544 stores and accumulates the hydraulic oil O whose pressure has been made constant by pressure compensating valve 543. When a predetermined pressure or more is accumulated in piping volume 544, the hydraulic oil O is supplied as a pilot pressure to a switching throttle valve 546 described later.

[0058] The variable throttle valve 545 is disposed in the second oil passage 522 between the pressure compensation valve 543 and the piping volume 544. The variable throttle valve 545 adjusts the amount of hydraulic oil O flowing through the second oil passage 522, and supplies the hydraulic oil O to the piping volume 544.

[0059] The switchable throttle valve 546 is disposed so as to connect the first oil passage 521 and the second oil passage 522. It has a valve with a throttle (referred to as a throttle valve) 5461 and a valve without a throttle (referred to as a normal valve) 5462. The switchable throttle valve 546 is switchable between the throttle valve 5461 and the normal valve 5462. When hydraulic oil O (pilot pressure) is supplied from the piping volume 544, the switchable throttle valve 546 switches to the throttle valve 5461 and supplies hydraulic oil O from the throttle valve 5461 to the main cylinder side (downstream side).

[0060] 4, the oil supply amount adjusting unit 54 includes a third oil passage 523 and a check valve 547. The third oil passage 523 is an oil passage branching off from the first oil passage 521, and is an oil passage connecting the upstream side of the throttle valve 541 and the downstream side of the switch type throttle valve 546. The check valve 547 is disposed in the third oil passage 523. The check valve 547 is provided to stop the flow of the hydraulic oil O from the upstream to the downstream.

[0061] When the hydraulic oil O is supplied to the main cylinder 44, the check valve 547 prevents the hydraulic oil O from passing through the third oil passage 523, and when the hydraulic oil O is discharged from the main cylinder 44, the hydraulic oil O passes through the third oil passage 523.

[0062] As described above, the hydraulic oil O from the oil supply amount adjustment unit is supplied to the main cylinder 44 through the slow return 55 and the decelerator valve 56. The slow return 55 always operates as a throttle valve when the hydraulic oil O is discharged from the main cylinder 44 and flows from the main cylinder 44 side to the oil supply amount adjustment unit 54 side. Therefore, when the work machine 3 descends, the work machine 3 descends at a low speed (slowly). Note that when the hydraulic oil O flows from the oil supply amount adjustment unit 54 side to the main cylinder 44 side, the slow return 55 allows the hydraulic oil O to pass through but does not operate as a throttle valve.

[0063] The de-serration valve 56 operates when the hydraulic oil O is discharged from the main cylinder 44 and flows from the main cylinder 44 side to the oil supply amount adjustment unit 54 side. The de-serration valve 56 has a normal valve 561, a throttle valve 562, and a rod 563. The de-serration valve 56 can be switched between the normal valve 561 and the throttle valve 562, and is switched to the throttle valve 562 by pushing in the rod 563.

[0064] The de-serration valve 56 operates when the hydraulic oil O is discharged from the main cylinder 44, that is, when the work machine 3 descends. When the work machine 3 descends to a predetermined height, the de-serration valve 56 switches to the throttle valve 562 as the rod 563 is pushed in by the work machine 3. The throttle valve 562 changes the amount of throttling of the hydraulic oil O according to the amount of pushing of the rod 563. The throttle valve 562 increases the amount of throttling as the amount of pushing of the rod 563 increases.

[0065] In this way, the decelerator valve 56 switches to the throttle valve 562 to reduce the discharge amount of the hydraulic oil O, and the work machine 3 that has fallen below a predetermined height (near the bottom end point) is lowered while decelerating. This allows the decelerator control to be performed when the work machine 3 is lowered.

[0066] According to the above configuration, the work machine 3 reaches the uppermost point while gradually decelerating its ascending speed, i.e., decelerating control is performed when the work machine 3 is ascending, so that shocks such as large shaking of the machine body when the work machine 3 reaches the uppermost point can be reduced.

[0067] <Control using 3D imaging information from an optical imaging device> The control unit C can perform the control described below by acquiring three-dimensional imaging information indicating the shape of the field from the optical imaging device LD. Here, FIG. 6 is an explanatory diagram for explaining an example of the illumination range of the optical imaging device LD. FIG. 6 is a schematic diagram illustrating the periphery of the working machine 3 as viewed from above the traveling vehicle body 2, and also shows the illumination range Lwd of the optical imaging device LD. As shown in FIG. 6, the illumination range Lwd is set to a linear shape with a width substantially equal to the working width W of the working machine 3 and a longitudinal direction in the left-right direction of the work vehicle 1. The setting of the illumination range Lwd can be changed by the control of the control unit C. In addition, in order to capture an image of the tilling state of the working machine 3, the illumination range Lwd is set behind and near the working machine 3.

[0068] Moreover, acquisition of three-dimensional imaging information by the optical imaging device LD (i.e., scanning of the optical radar) is performed at predetermined time intervals (for example, 5 seconds), and the acquired three-dimensional imaging information is recorded in the control unit C, so that the history of data over time can be referred to as appropriate. Moreover, in addition to using the data by the control unit C, the worker can also confirm it by outputting it to the image and audio output unit 245 through a predetermined operation.

[0069] Below, we will explain examples of control by the control unit C using three-dimensional imaging information by the optical imaging device LD. Note that the control examples by the control unit C are not limited to the following. Also, the following control examples can be independently executed by the control unit C by, for example, setting a predetermined operation by an operator as a starting condition.

[0070] [Control example] (I) Evaluation of tillage conditions (Method 1) The control unit C generates two-dimensional image data (hereinafter referred to as cultivation information) indicating the cultivated condition of the field from the acquired three-dimensional imaging information for each scan (i.e., each time three-dimensional imaging information is acquired). Fig. 7 is a diagram showing an example of cultivation information generated by the control unit C in the evaluation of the cultivated condition (method 1). As shown in Fig. 7, the cultivation information includes a field elevation line Ln1 indicating the height of the top surface of the field relative to a set reference horizontal line Ln0, and further includes an average elevation horizontal line Ln2, which is a horizontal line indicating the average height of the field elevation line Ln1.

[0071] Here, in Fig. 7, the left side as viewed from the paper surface corresponds to the left side of the work vehicle 1, and the right side corresponds to the right side, but the method of determining the left-right direction in data generation is not limited to this (the same applies to Figs. 8, 9, and 11 to 13). The set reference horizontal line Ln0 is a horizontal line that serves as a reference indicating a height that is set in advance in the control unit C by, for example, a predetermined input operation by the operator. The field elevation line Ln1 is generated from three-dimensional imaging information, and the elevation of the line segment at each point in the left-right direction indicates the elevation of the top surface of the field relative to the set reference horizontal line Ln0, and the shape of the line segment corresponds to the height of the top surface of the field (or the uneven shape of the field). When the optical imaging device LD is attached to the work implement 3, the optical imaging device LD is also tilted according to the tilt (rolling angle) of the work implement 3, and the field elevation line Ln1 based on the horizontal direction of the field is calculated by subtracting (cancelling) the tilt (rolling angle) by a predetermined calculation. The horizontal direction of the field is derived, for example, by a spirit level (not shown) provided on the work vehicle 1.

[0072] The elevation average horizontal line Ln2 is calculated from the average value of the height difference between the field elevation line Ln1 and the set reference horizontal line Ln0 at each point in the left-right direction (more specifically, the elevation average horizontal line Ln2 is a horizontal line set at a height position obtained by adding the height of the set reference horizontal line Ln0 to the average value of the height difference between the field elevation line Ln1 and the set reference horizontal line Ln0 at each point in the left-right direction). Then, the control unit C compares the height indicated by the elevation average horizontal line Ln2 (see FIG. 7) with a preset target value (target height), and if the difference is within a predetermined threshold range, the evaluation is determined to be "good", and if the difference is within the predetermined threshold range, the evaluation is determined to be "poor". The evaluation result is output to the image and audio output unit 245, so that the operator can check it. Note that the evaluation is performed, for example, every time the control unit C acquires three-dimensional imaging information, but the timing and time interval of the evaluation can be set appropriately. The evaluation may also be performed using the average value at a predetermined time interval.

[0073] Furthermore, the control unit C may be configured to, when the difference between the height indicated by the height mean horizontal line Ln3 and a preset target value (target height) exceeds a predetermined limit value, output a notice to that effect to the image and sound output unit 245 to warn the operator, and automatically shift the PTO speed to a higher gear. Also, the control unit C may be configured to output instruction information from the image and sound output unit 245 to prompt the operator to reduce the vehicle speed. This allows the operator to check the finished state of the tilled field by the output of the output unit 245 without visually inspecting it, and further allows the operator to quickly notice when the tilling is insufficient, thereby improving the accuracy of the tilling, improving the convenience of the operator, and improving the work efficiency. The operator can effectively prevent the tilling from being insufficient by reducing the vehicle speed based on the instruction information.

[0074] (II) Evaluation of tillage conditions (Method 2) Fig. 8 is a diagram showing an example of tillage information generated by the control unit C in the tillage condition evaluation (method 2). The method of deriving the set reference horizontal line Ln0 and the field elevation line Ln1 in Fig. 8 is similar to that in the tillage condition evaluation (method 1) in Fig. 7, and therefore will not be described.

[0075] In the tillage condition evaluation (method 2), it is determined whether the field elevation line Ln1 is within a target range Lg1 indicating the upper and lower limit heights that are targets for the top and bottom heights of the field at each point in the left-right direction. If the field elevation line Ln1 is within the target range Lg1 at any point in the left-right direction, the evaluation is made "good", and if the field elevation line Ln1 is outside the target range Lg1 at any point in the left-right direction, the evaluation is made "poor". The evaluation result is output to the image and audio output unit 245 so that the worker can check it. The timing and time interval of the evaluation are the same as those in the tillage condition evaluation (method 1). This allows the worker to check the finished state of the field after tilling by looking at the output from the output unit 245 without having to visually inspect it, as described above, and further allows the worker to quickly notice if the tilling is insufficient, thereby improving the accuracy of tilling, improving convenience for the worker, and improving work efficiency.

[0076] (III) Rolling control of work equipment based on 3D imaging information The control unit C performs rolling control of the working machine 3 based on the tilling information. Fig. 9 is a diagram showing an example of tilling information generated by the control unit C in the rolling control of the working machine 3 based on the three-dimensional imaging information. In Fig. 9, the method of deriving the setting reference horizontal line Ln0 and the field elevation line Ln1 is similar to the examples in Figs. 7 and 8 above, and therefore a description thereof will be omitted.

[0077] As shown in Fig. 9, in the rolling control of the working machine 3 based on the tilling information, the control unit C calculates a tilled surface inclination line Ln3 indicating the inclination of the top surface of the tilled field. Here, the field inclination line Ln is an approximation line calculated from the field elevation line Ln1 by the least squares method, and the inclination of this line segment indicates the inclination of the top surface of the tilled field. In other words, since it indicates the inclination of the actual top surface of the tilled field, the control unit C performs rolling control of the working machine 3 so as to make the field inclination line Ln3 horizontal (in other words, so that the top surface of the actual tilled field is horizontal). Details will be described below.

[0078] First, the control unit C calculates the field inclination line Ln3 shown in Figure 9 for each scan (i.e., each time three-dimensional imaging information is acquired) from the acquired three-dimensional imaging information, and determines the tilled surface inclination angle θx (in the illustrated example, a downward inclination), which is the inclination angle (the angle between two line segments) based on the set reference horizontal line Ln0 (which may be any line segment indicating the horizontal direction of the field).

[0079] The following control will be described with reference to Fig. 10. Fig. 10 is a schematic rear view of the work vehicle 1 for explaining the rolling control of the work implement 3 based on the tilling information. In Fig. 10, the inclination angle θ1 of the traveling body 2 with respect to the horizontal direction detected by the inclination angle detection device S1 is illustrated, and Gr is the field. Here, in normal rolling control (horizontal control) by the control unit C, the rolling attitude (roll angle) of the work implement 3 is controlled by the control of the rolling mechanism 4B in a rotation direction and angle that cancels out the inclination angle θ1 of the traveling body 2. That is, in the illustrated example, the work implement 3 is rotated (rolled) downward by the roll angle θ2 (i.e., the inclination angle θ1) to make the attitude horizontal.

[0080] Here, as described above, the inclination of the top surface of the field after the actual cultivation is calculated as the cultivation surface inclination angle θx (downward) from the acquired cultivation information, so that the control unit C controls the rolling mechanism 4B to rotate the working machine 3 by the cultivation surface inclination angle θx as the rotation angle in a rotation direction (upward) that cancels the cultivation surface inclination angle θx in order to make the top surface of the field after the actual cultivation horizontal. With this configuration, the rolling posture of the working machine 3 can be corrected (modified) based on the inclination of the top surface of the field after the actual cultivation, so that the field can be made horizontal even if the finished field scene after the cultivation is inclined in normal rolling control. As a result, the finished field scene after the cultivation can be made well horizontal, and the quality of the cultivation work can be improved significantly. In the above example, the rotation direction that cancels out the tillage surface inclination angle θx is described as being upward, but in actuality, when the inclination angle of the tillage surface θx is upward, the rotation direction that cancels out the tillage surface inclination angle θx is downward.

[0081] (IV) Recording the location of depressions in the field FIG. 11 is an example of tillage information generated by the control unit C for control related to recording the position of a depression in a field. The method of deriving the set reference horizontal line Ln0, the field elevation line Ln1, and the elevation average horizontal line Ln2 shown in FIG. 11 is the same as that in FIG. 7, so the description will be omitted. The control unit C generates tillage information every time it acquires three-dimensional imaging information showing the shape of the field from the optical imaging device LD (for example, every 5 seconds), and when a part of the field elevation line Ln1 having a width of a predetermined range Lg2 or more in the left-right direction and lower than the elevation average horizontal line Ln2 continues for a certain period of time (for example, 15 seconds), it determines that a depression has occurred in the field and records the position information. This allows the worker to check the position of the depression in the field after the tilling work. For example, the image / audio output unit 245 may be configured to display a field map showing the shape of the field (map data including the size, shape, and position information of the field that is pre-stored in the control unit C) and the positions of depressions on the field map.

[0082] (V) Generation of 3D images of the top surface of a field after tillage FIG. 12 is an image diagram of a 3D image generated in relation to control related to the generation of a 3D image of the top surface of a field after cultivation. As shown in FIG. 12, the control unit C may be configured to generate and display a 3D image from continuous data of cultivation information over time, including information on the field elevation line Ln1 and the set reference horizontal line Ln0. This allows the operator to visually grasp the state of the field in three dimensions, improving the operator's convenience. At this time, the above-mentioned depression may be determined at the same time, and a predetermined color may be applied to the area determined to be a depression when the 3D image is generated.

[0083] (VI) Determination of residual tillage Fig. 13 is a diagram showing an example of tillage information generated by the control unit C in the determination control of residual tillage based on three-dimensional imaging information. In Fig. 13, the method of deriving the setting reference horizontal line Ln0 and the field elevation line Ln1 is similar to the examples in Figs. 7 and 8 above, and therefore the explanation will be omitted.

[0084] In the residual tillage determination control based on the three-dimensional imaging information, the control unit C sets the irradiation range Lwd of the optical imaging device LD to the working width W of the working machine 3 plus a residual tillage determination range Lg3 of, for example, about 150 mm on each side, or on either side. Then, the control unit C calculates the field elevation line Ln1 shown in FIG. 13 for each scan (i.e., each time the three-dimensional imaging information is acquired) from the acquired three-dimensional imaging information, and when a flat portion occurs on the field elevation line Ln1 within the residual tillage determination range Lg3 (i.e., when the field elevation line Ln1 has no unevenness and the inclination in the left-right direction is approximately 0), it determines that residual tillage exists, and outputs a message to that effect to the image and audio output unit 245 to warn the operator. This allows the operator to easily find residual tillage. Also, when it is determined that there is remaining tillage, the automatic driving may be temporarily stopped.Furthermore, the driving may be controlled so that the vehicle moves backward and the remaining tillage is re-cultivated.

[0085] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned embodiment. It goes without saying that the present invention can be modified appropriately within the scope of the technical concept.

[0086] In the embodiment of Figure 6, an example is shown in which the illumination range Lwd has a width that is approximately the same as the working width W of the work machine 3 and is set to a linear shape with its longitudinal direction in the left-right direction of the work vehicle 1, but it may also be configured to scan in an arc shape.

[0087] In addition, in the above embodiment, the optical imaging device LD is attached to the work machine 3, but it may be disposed on the traveling vehicle body 2, for example, in approximately the center part in the left-right direction of the upper end of the safety bar 25.

[0088] In addition to the above control example, the control device C may be configured to sum up the lengths of rod-like objects within the scanning range of the optical imaging device LD, and thereby evaluate the plowing status. That is, for example, if the sum of the lengths is longer than a predetermined length, it is judged as "poor", and if it is shorter, it is judged as "good", and output the result.

[0089] In addition to the above control example, the control device C may be configured to determine the size of the soil mass from the magnitude of the unevenness by deriving the field elevation line Ln1. That is, if the difference in height between the unevenness and the distance between the deep valleys is large, the control device C may be configured to determine that the soil mass is large and to display that fact on the image and audio output unit 245. Furthermore, if the soil mass is determined to be large, the control device C may be configured to display an announcement encouraging the operator to increase the PTO speed or decrease the vehicle speed.

[0090] The control device C may be configured to issue a warning when the height mean horizontal line Ln3 becomes higher than a predetermined value immediately after the start of plowing in the control example shown in Fig. 7. In addition, the control device C may be configured to automatically adjust the decelerator to slow down the descent speed of the work implement 3. [Explanation of symbols]

[0091] 1. Work vehicle (tractor) 2 Running vehicle 21 Front wheel 22 Rear wheel 23 Bonnet 24 Control Unit 25 Safety bar (Rops) 26 PTO shaft 27 PTO coupling device 241 Cockpit 242 Steering Wheel 243 Lift switch 244 Position Lever 245 Video and audio output section 3. Work equipment 31 Cultivating Claw 32 Rotary cover 4 Lifting device 41 Lift arm 411 Rotating shaft 412 Lift arm angle sensor 42 Lower Link 43 Lift Rod 431 Hydraulic Cylinder (Horizontal Cylinder) 44 Main Cylinder 441 Hydraulic Cylinder 442 Rod 50 Hydraulic circuit 51 Pump 511 Main pump 512 Sub-pump 52 Oil road 521 No. 1 oil road 522 2nd oil road 523 3rd oil road 53 Main Control Valve 54 Oil supply amount adjustment unit 541 Throttle valve 542 Directional control valve 543 Pressure Compensation Valve 544 Piping volume 545 Variable throttle valve 546 Switching throttle valve 5461 Restricted valve (restrictor valve) 5462 Valve without restriction (normal valve) 55 Slow Return 56 Decera Valve 561 Normal valve 562 Throttle valve 563 Rod C control section

Claims

1. A work vehicle equipped with a work machine for cultivating a field, an optical imaging device that captures an image of a farm field; and a control unit that acquires three-dimensional imaging information indicating a shape of the farm field from the optical imaging device, The optical imaging device is configured to linearly scan and image a cultivated field, The control unit of this work vehicle is configured to calculate a field elevation line, which is a line segment indicating the elevation of the top surface of the field, from the acquired three-dimensional imaging information, evaluate whether the vertical width of the calculated field elevation line falls within a specified range, and output the evaluation result from an output unit.

2. The work vehicle is provided with a rolling mechanism that rotates the work implement, and the control unit controls the rolling mechanism to enable rolling control of the work implement, The control unit calculates a tillage surface inclination line indicating the inclination of the top surface of the field after tilling by approximating the calculated field elevation line with a straight line, and calculates a tillage surface inclination angle which is the angle between the calculated tillage surface inclination line and a line segment indicating the horizontal direction of the field; 2. The work vehicle according to claim 1, wherein the rolling control is configured to correct the attitude of the work implement so as to achieve a rotation direction and angle that cancels the calculated inclination angle of the tillable surface.

3. The work vehicle according to claim 1, characterized in that the control device is configured to calculate an average horizontal elevation line, which is a horizontal line indicating the average height of the field elevation lines, from the calculated field elevation lines, and to output instruction information from an output unit that urges an operator to slow down the vehicle speed if a difference between the height indicated by the calculated average horizontal elevation line and a preset target height exceeds a predetermined limit value.

Images