Operation control system for work vehicle

Abstract

To limit an operating speed of an operating part of a work vehicle by an operator simply performing an operation such as selecting a level according to the operator's skill or content of work from a selection screen, thereby enabling even an operator who is inexperienced in operating the work vehicle to operate the work vehicle with ease.SOLUTION: An operation control system for a work vehicle comprises a control device 34 having a hydraulic pump control unit 343 that controls a hydraulic pump based on a level selected by an operator from n levels (n is an integer of 2 or more). The hydraulic pump control unit 343 has operation amount / current value correspondence data in which an operation amount of a control lever and a current value are associated for each of the n levels. Then, a current value corresponding to the current operation amount of the control lever is obtained from the operation amount / current value correspondence data corresponding to the level selected by the operator, and an amount of pressurized oil discharged by the hydraulic pump is controlled based on the obtained current value.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a motion control system for a work vehicle. [Background technology]

[0002] A widely known example of a work vehicle is a crawler-type skid steer loader. In this type of work vehicle, an attachment such as a bucket is detachably attached to the tip of an arm that is mounted on the vehicle body so as to be movable up and down. By swinging the bucket up and down, for example, various tasks such as moving excavated soil and sand can be performed. By attaching and detaching the attachment depending on the purpose of the work, various tasks can be performed.

[0003] Furthermore, this type of work vehicle has a cabin on top of the vehicle for the operator to ride in. The cabin has a seat on which the operator sits, and near the seat are provided an operating lever for operating the work vehicle to travel and an operating lever for operating attachments such as a bucket (see Patent Document 1).

[0004] The work vehicle described in Patent Document 1 allows the operator to perform the desired operation by operating the corresponding operating lever when traveling the work vehicle or operating attachments such as a bucket. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2022-56577 Summary of the Invention [Problem to be solved by the invention]

[0006] In the above-mentioned working vehicle, there is a demand for the operating part of the working vehicle to be operated while being limited to the operating speed desired by the operator. In particular, for an operator who is not familiar with operating a working vehicle, if the operating speed of the operating part is fast, the operator may not be able to operate the vehicle with ease. Therefore, for an operator who is not familiar with operating a working vehicle, there is a demand for the operating part of the working vehicle to be operated at an operating speed according to his / her skill and the work content. Here, the operating part of the working vehicle refers to a traveling device for traveling the working vehicle and a working device for performing work. The traveling device includes a crawler, a hydraulic motor for traveling, and the like. The working device also includes an attachment such as a bucket, a hydraulic cylinder, and the like.

[0007] In addition, when a work vehicle is traveling straight, if there is wear on either the left or right crawler, or if soil and sand are unevenly piled in the bucket, the vehicle may turn in a direction that the operator does not intend. In such cases, the operator must perform an operation to correct the direction of travel of the work vehicle. However, an operator who is inexperienced in operating a work vehicle may not be able to properly correct the direction of travel.

[0008] The above-mentioned control of the travel speed of the work vehicle, control of the operating speed of the working equipment, and control for maintaining the straightness of the work vehicle can all be performed by controlling the operating speed of the operating parts of the work vehicle. In this case, if it is possible to limit the operating speed of the operating parts of the work vehicle, even an operator who is unfamiliar with operating a work vehicle can operate the work vehicle with ease.

[0009] The present invention has been made to solve the above-mentioned problems, and aims to provide a work vehicle operation control system that allows an operator to limit the operating speed of the operating parts of a work vehicle by simply selecting a level that corresponds to his or her skill level and the work content from a selection screen displayed on the display unit, thereby allowing even an operator who is unfamiliar with operating a work vehicle to operate the work vehicle with ease. [Means for solving the problem]

[0010] [1] The working vehicle motion control system of the present invention is a working vehicle motion control system that controls the operation of an operating part by controlling a hydraulic pump based on a current value output by operation of an operating lever, and n levels from a first level to an nth level (n is an integer of 2 or more) are set for the operating speed when the operating part operates. The working vehicle motion control system of the present invention comprises a hydraulic pump, a display unit that displays a selection screen that allows an operator to select one of the n levels, and a control device having a hydraulic pump control unit that controls the hydraulic pump based on the level selected by the operator, and is characterized in that the hydraulic pump control unit limits the current value in accordance with the level selected by the operator, and controls the amount of pressure oil discharged by the hydraulic pump based on the limited current value.

[0011] [2] In the working vehicle operation control system of the present invention, the operation control of the operation unit is a travel speed control that controls the travel speed of a travel device of the working vehicle, and n levels from a first level to an n-th level (n is an integer of 2 or more) are set for the travel speed of the travel device. The working vehicle is provided with a hydraulic motor for traveling that is driven by pressure oil discharged from the hydraulic pump. It is preferable that the hydraulic pump control unit has operation amount / current value correspondence data in which the operation amount of the operating lever and the current value are associated with each of the n levels, and obtains a current value for the current amount of the operating lever at the current point in time from the operation amount / current value correspondence data corresponding to the level selected by the operator, and controls the amount of pressure oil discharged by the hydraulic pump based on the obtained current value.

[0012] [3] In the working vehicle motion control system of the present invention, the motion control of the operation unit is a motion speed control of a working device that controls the motion speed of a working device of the working vehicle, and n levels from a first level to an nth level (n is an integer of 2 or more) are set for the motion speed of the working device. The system further includes a hydraulic cylinder that is driven by pressure oil discharged from the hydraulic pump. It is preferable that the hydraulic pump control unit has operation amount / current value correspondence data in which the operation amount of the control lever and the current value are associated with each of the n levels, and obtains a current value for the current amount of the current of the current lever from the operation amount / current value correspondence data corresponding to the level selected by the operator, and controls the amount of pressure oil discharged by the hydraulic pump based on the obtained current value. Working vehicle motion control system.

[0013] [4] In the work vehicle operation control system of the present invention, it is preferable that the operation amount / current value correspondence data corresponding to each level is set in ascending or descending order from the first level to the nth level, with the current values ​​corresponding to the operation amounts of the operating lever being set in that order.

[0014] [5] In the work vehicle operation control system of the present invention, it is preferable that the hydraulic pump control unit filters the current value using a filter in which a parameter for suppressing change in the current value is set corresponding to each level, and the parameter has a value according to the magnitude of change in the current value in the operation amount / current value correspondence data corresponding to each level.

[0015] [6] In the working vehicle motion control system of the present invention, the motion control of the operation unit is a left-side travel speed control for controlling the travel speed of the left-side travel device of the pair of left and right travel devices of the working vehicle, and a right-side travel speed control for controlling the travel speed of the right-side travel device of the pair of left and right travel devices of the working vehicle. For the travel speed of the left-side travel device, n levels from a first level to an n-th level (n is an integer of 2 or more) are set as left levels, and for the travel speed of the right-side travel device, n levels from a first level to an n-th level are set as right levels, and the display unit displays a selection screen that allows an operator to select one of the n left levels and the n right levels. The system includes a left hydraulic motor and a right hydraulic motor driven by pressure oil discharged from the hydraulic pump. The hydraulic pump control unit has left level-current value correspondence data in which a current value is set corresponding to each level of the n left levels, and right level-current value correspondence data in which a current value is set corresponding to each level of the n right levels. Then, a current value corresponding to a level selected by the operator from the n-stage left level is obtained from the left level-current value correspondence data, and the amount of pressure oil discharged from the hydraulic pump to drive the left hydraulic motor is controlled based on the obtained current value. Also, a current value corresponding to a level selected by the operator from the n-stage right level is obtained from the right level-current value correspondence data, and the amount of pressure oil discharged from the hydraulic pump to drive the right hydraulic motor is controlled based on the obtained current value.

[0016] [7] In the work vehicle operation control system of the present invention, it is preferable that the magnitudes of the current values ​​set corresponding to each level of the left level-current value correspondence data and each level of the right level-current value correspondence data are set in ascending or descending order from the first level to the nth level.

[0017] [8] In the work vehicle motion control system of the present invention, it is preferable that the hydraulic pump control unit further performs PID (Proportional Integral Derivative) control so that the traveling speed of the left traveling device and the traveling speed of the right traveling device each become speeds corresponding to the selected level.

[0018] [9] In the work vehicle motion control system of the present invention, the PID control sets target values ​​for the rotation speed of the left hydraulic motor and the rotation speed of the right hydraulic motor corresponding to each level, and controls the hydraulic pump so that the rotation speed of the left hydraulic motor and the rotation speed of the right hydraulic motor become the set target values. Effect of the Invention

[0019] According to the working vehicle operation control system of the present invention, the current value output by the operation of the control lever can be limited simply by the operator selecting a level according to his / her skill level and the type of work from the selection screen displayed on the display unit, thereby making it possible to operate the operating unit of the working vehicle at a speed limited to the speed corresponding to the selected level.

[0020] For example, in the case where the operation control of the operating unit is a travel speed control that controls the travel speed of a travel device of a work vehicle, when an operator selects the lowest level among a plurality of levels, even if the operation amount of the operation lever is the same, the work vehicle travels in a state limited to a lower speed than the normal travel speed. This allows even an operator who is unfamiliar with operating a work vehicle to travel the work vehicle with ease.

[0021] Furthermore, in the case where the operation control of the operating unit is an operation speed control of a working device that controls the operation speed of a working device of a work vehicle, for example, when an operator selects the lowest level among a plurality of levels, the working device operates in a state limited to a lower speed compared to the normal operating speed even if the operation amount of the operation lever is the same. This allows even an operator who is inexperienced in operating a work vehicle to operate the working device with ease.

[0022] Furthermore, in cases where the operational control of the operating unit is a left-side travel speed control for controlling the travel speed of the left-side travel device of a pair of left and right travel devices of the work vehicle, and a right-side travel speed control for controlling the travel speed of the right-side travel device of a pair of left and right travel devices of the work vehicle, when the straight-line running ability of the work vehicle is impaired, the operator can maintain the straight-line running ability of the work vehicle by simply performing a simple operation of selecting a predetermined level from a plurality of levels. This allows even an operator who is unfamiliar with operating a work vehicle to easily perform operations to maintain the straight-line running ability of the work vehicle. [Brief description of the drawings]

[0023] [Figure 1] 1 is a diagram shown for explaining a work vehicle 1 to which a work vehicle operation control system according to a first embodiment is applied. FIG. [Diagram 2] 1 is a diagram shown for explaining a motion control system 30A for a work vehicle according to the first embodiment. FIG. [Diagram 3] 3 is a diagram showing an example of a selection screen 331 displayed on the display unit 33. FIG. [Figure 4] FIG. 2 is a diagram for explaining the operation amount / current value correspondence data DT1, DT2, and DT3. [Diagram 5] 4 is a flowchart illustrating a motion control process in the working vehicle motion control system 30A according to the first embodiment. [Figure 6]FIG. 11 is a diagram shown for explaining a working vehicle operation control system 30B according to a second embodiment. [Figure 7] 13 is a diagram showing an example of a selection screen 333 displayed on the display unit 33. FIG. [Figure 8] 10 is a flowchart illustrating a motion control process in a motion control system 30B for a work vehicle according to the second embodiment. [Figure 9] FIG. 11 is a diagram shown for explaining a working vehicle operation control system 30C according to a third embodiment. [Figure 10] 13 is a diagram showing an example of a selection screen 336 displayed on the display unit 33. FIG. [Figure 11] 11 is a flowchart illustrating a motion control process in a working vehicle motion control system 30C according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Each embodiment described below shows a preferred form for carrying out the invention, and does not limit the invention according to the claims. In addition, not all of the elements and combinations thereof described in each embodiment are essential to the present invention. In addition, each drawing for explaining each embodiment shows an example, and does not necessarily strictly reflect the actual shape, dimensions, etc.

[0025] The working vehicle motion control system shown in each of the following embodiments is a working vehicle motion control system that controls the motion of the operating part by controlling a hydraulic pump based on a current value corresponding to the operation of an operating lever. Furthermore, n levels, from a first level to an nth level (n is an integer of 2 or more), are set for the operating speed when the operating part operates, and the current value is limited according to a level selected by the operator from among the n levels. In this way, the operating part of the working vehicle is operated in a state where the speed is limited to the speed corresponding to the selected level. Each embodiment of the working vehicle motion control system will be described below.

[0026] [Embodiment 1] In the work vehicle motion control system according to the first embodiment, the above-mentioned "operation control of the operating unit" is a travel speed control that controls the travel speed of a travel device of the work vehicle. The above-mentioned "n levels from the first level to the nth level" are three levels: a first level L1, a second level L2, and a third level L3. The work vehicle motion control system according to the first embodiment will be described below.

[0027] FIG. 1 is a diagram for explaining a work vehicle 1 to which a work vehicle motion control system 30A according to a first embodiment is applied. The work vehicle 1 will be explained using as an example a "crawler loader" (also called a "track loader") capable of mounting an attachment such as a bucket (not shown) to the tip of an arm 18. Note that the external configuration of the work vehicle 1 is not the gist of the present invention and will therefore only be described briefly. The work vehicle 1 shown in FIG. 1 is also common to work vehicles in other embodiments described below.

[0028] In the following description, the side of the work vehicle 1 to which an attachment such as a bucket is attached is referred to as the "front", and the side opposite the side to which the attachment such as a bucket is attached is referred to as the "rear". The bottom side of the work vehicle 1 is referred to as the "bottom", and the side opposite the bottom is referred to as the "top". The left side of the work vehicle 1 when viewed from behind is referred to as the "left", and the right side is referred to as the "right".

[0029] 1, the work vehicle 1 has a main body frame 11, a pair of left and right traveling devices 12 attached to the main body frame 11 and having crawlers (endless tracks) 13, a working device 14 attached to the main body devices, and a cabin 15 provided at the upper center of the main body frame 11. When describing the pair of left and right traveling devices 12, the left traveling device and the right traveling device will be described as the "left traveling device 12L" and the "right traveling device 12R" separately.

[0030] The working device 14 is composed of an arm 18 arranged to surround the front, rear, left and right sides of the cabin 15, a pair of left and right hydraulic cylinders (arm cylinders) 19 attached across the main frame 11 and the arm 18, and an attachment (not shown) such as a bucket attached to the tip of the arm 18.

[0031] The cabin 15 is formed in a box shape, and is provided with a front door (not shown) that can be opened and closed at the front of the work vehicle 1. An operator seat 17 on which an operator sits facing the front of the vehicle is provided in the cabin 15, and operation levers 20 are provided on the left and right sides of the operator seat 17. When describing the operation levers 20 separately, they will be described as the "left operation lever 20L" and the "right operation lever 20R". Note that in FIG. 1, the operation lever 20L provided on the left side is not shown because it is in a position that cannot be seen with the naked eye.

[0032] Here, the left operating lever 20L is an operating lever located on the left hand side when the operator is seated in the operator seat 17, and is an operating lever for driving the work vehicle 1. On the other hand, the right operating lever 20R is an operating lever located on the right hand side when the operator is seated in the operator seat 17. This operating lever 20R is an operating lever for operating (swinging up and down) the arm 18 to operate an attachment such as a bucket. In the following description, the left operating lever 20L may be abbreviated to operating lever 20L, and the right operating lever 20R may be abbreviated to operating lever 20R.

[0033] Next, the working vehicle motion control system 30A according to the first embodiment will be described. As described above, the working vehicle motion control system 30A according to the first embodiment controls the traveling speed of the traveling gear 12 of the working vehicle 1. A plurality of levels are set for the traveling speed of the traveling gear 12, and traveling speed control is performed corresponding to a level selected by an operator from the plurality of levels. Here, the plurality of levels will be described as being set in three stages, a first level L1, a second level L2, and a third level L3, as described above.

[0034] The traveling speed of the traveling gear 12 is also the traveling speed of the work vehicle 1. For this reason, in the work vehicle operation control system 30A according to the first embodiment, "the traveling speed of the traveling gear 12" may be expressed as "the traveling speed of the work vehicle 1."

[0035] Furthermore, of the first level L1, second level L2 and third level L3, the third level L3 is a level set for the normal speed of the work vehicle 1. Therefore, when set to the third level L3, the work vehicle 1 travels at a normal speed. Here, the "normal speed" refers to the speed of the work vehicle 1 in the absence of a function for setting levels. In the following description, "the first level L1, the second level L2 and the third level L3" may also be expressed as "the first level L1 to the third level L3".

[0036] Fig. 2 is a diagram illustrating a motion control system 30A for a work vehicle according to embodiment 1. As shown in Fig. 2, the motion control system 30A for a work vehicle according to embodiment 1 includes a hydraulic pump 31, a hydraulic motor 32 for traveling driven by pressure oil discharged from the hydraulic pump 31, a display unit 33 that displays a selection screen 331 (see Fig. 3) that allows an operator to select one of the first level L1 to the third level L3, and a control device 34 having a hydraulic pump control unit 343 that controls the hydraulic pump 31 based on the level selected by the operator.

[0037] First, the display unit 33 and the selection screen 331 displayed on the display unit 33 will be described, followed by a description of other components such as the control device 34. The display unit 33 is a touch panel monitor, and functions as a user interface into which information can be input. The display unit 33 is provided within the cabin 15 of the work vehicle 1 (see FIG. 1). Furthermore, the display unit 33 is provided in a position within the cabin 15 where an operator seated in the operator seat 17 can easily touch the selection screen 331 with his or her finger.

[0038] Fig. 3 is a diagram showing a schematic example of a selection screen 331 displayed on the display unit 33. The selection screen 331 shown in Fig. 3 allows the operator to select one of three levels, a first level L1 to a third level L3.

[0039] 3, the display segments corresponding to the first level L1 to the third level L3 are sequentially lit each time the level selection button 332R on the right side shown in the figure is touched once. For example, when the level selection button 332R is touched once, the display segment corresponding to the first level L1 is lit, indicating that the first level L1 is selected.

[0040] Furthermore, when the level selection button 332R is touched twice, the display segments corresponding to the first level L1 and the second level L2 light up, indicating that the second level L2 is selected. When the level selection button 332R is touched three times, all the display segments corresponding to the first level L1 to the third level L3 light up, indicating that the third level L3 is selected. Note that FIG. 3 illustrates a state in which the display segment of the first level L1 is lit up.

[0041] Furthermore, when all of the display segments corresponding to the first level L1 to the third level L3 are lit, each time the left-side level selection button 332L is touched once, the display segments corresponding to the first level L1 to the third level L3 are turned off by one level.

[0042] The operator selects a desired level according to his / her skill or the work content from the selection screen 331 shown in Fig. 3. For example, if the operator wishes to drive the work vehicle 1 at a low speed, the first level L1 is selected. If the operator wishes to drive the work vehicle 1 at a medium speed, the second level L2 is selected. If the operator wishes to drive the work vehicle 1 at a normal speed, the third level L3 is selected. As a result, the work vehicle 1 will drive at a speed limited to the speed corresponding to the selected level, which will be described later.

[0043] Next, a description will be given of the control device 34. The control device 34 has a display control unit 341, a level determination unit 342, and a hydraulic pump control unit 343, as shown in FIG.

[0044] The display control unit 341 exchanges information with the display unit 33. The level determination unit 342 determines which level selected from the selection screen 331 displayed on the display unit 33 is among the first level L1 to the third level L3.

[0045] The hydraulic pump control section 343 has "operation amount / current value correspondence data DT1, DT2, DT3" in which the operation amount of the operating lever 20L and the current value are associated with each other. Here, the operation amount / current value correspondence data DT1 corresponds to the first level L1, the operation amount / current value correspondence data DT2 corresponds to the second level L2, and the operation amount / current value correspondence data DT3 corresponds to the third level L3. The operation amount / current value correspondence data DT1, DT2, DT3 will be described in detail later.

[0046] Moreover, the hydraulic pump control unit 343 filters the current value using a filter in which parameters for suppressing changes in the current value are set. The parameters are set corresponding to each of the first level L1 to the third level L3, where the parameter set corresponding to the first level L1 is parameter PM1, the parameter set corresponding to the second level L2 is parameter PM2, and the parameter set corresponding to the third level L3 is parameter PM3.

[0047] The parameters PM1, PM2, and PM3 have values ​​(called parameter values) corresponding to the magnitude of change in the current value in the manipulated variable-current value correspondence data corresponding to each level. The parameter values ​​corresponding to the change in the current value will be described later.

[0048] Next, the operation amount / current value correspondence data DT1, DT2, and DT3 in which the operation amount and current value of the operating lever 20L are associated with each other will be described.

[0049] Fig. 4 is a diagram for explaining the operation amount / current value correspondence data DT1, DT2, and DT3. In Fig. 4, the horizontal axis represents the operation amount α of the operating lever 20L, and the vertical axis represents the current value I. Note that the current value I increases from zero (0) toward the top of the figure along the vertical axis.

[0050] Moreover, the dashed line in Fig. 4 indicates the relationship between the operation amount α of the control lever 20L and the current value I at the first level L1, and corresponds to the operation amount / current value correspondence data DT1. Moreover, the dashed line in Fig. 4 indicates the relationship between the operation amount α of the control lever 20L and the current value I at the second level L2, and corresponds to the operation amount / current value correspondence data DT2. Moreover, the solid line in Fig. 4 indicates the relationship between the operation amount α of the control lever 20L and the current value I at the third level L3, and corresponds to the operation amount / current value correspondence data DT3.

[0051] Here, the operation amount α of the operating lever 20L is represented by the tilt angle of the operating lever 20L from the neutral position. However, in Fig. 4, the tilt angle is represented by a percentage (%) of the maximum tilt angle of the operating lever 20L.

[0052] In other words, the maximum tilt angle is 100%, and the operation amount is expressed as a percentage (%) of the maximum tilt angle, such that if the tilt angle is 1 / 10 of the maximum tilt angle, the operation amount is 10%, and if the tilt angle is 1 / 2 of the maximum tilt angle, the operation amount is 50%.

[0053] As shown in Fig. 4, immediately after starting to tilt the operating lever 20L, in a section where the operation amount of the operating lever is relatively small (for example, a section where the operation amount is up to α1), the change in the current value is large. Thereafter, as the operation amount of the operating lever 20L increases from α1, the current value increases gradually. Then, when the operation amount of the operating lever 20L exceeds, for example, αn, the change in the current value becomes large again. Note that the relationship between the operation amount of the operating lever 20L and the current value shown in Fig. 4 is one example and is not limited thereto, and can be set appropriately.

[0054] Here, the operation amount / current value correspondence data DT1, DT2, DT3 corresponding to each of the first level L1 to third level L3 are set in ascending or descending order of the magnitude of the current value when the operation amount of the operating lever 20L is the same, from the first level L1 to the third level L3, as shown in Fig. 4. Note that in the work vehicle operation control system 30A according to the first embodiment, the current value is set in ascending order. In other words, the current value when the operation amount of the operating lever 20L is the same is set so that the current value increases in the order of the first level L1 to the third level L3.

[0055] In this way, the magnitude of the current value when the operation amount of the operating lever 20L is the same is set in ascending order from the first level L1 to the third level L3. As a result, when the operation amount of the operating lever 20L is the same, the travel speed of the work vehicle 1 is faster when the second level L2 is selected than when the first level L1 is selected. Furthermore, when the third level L3 is selected, the travel speed of the work vehicle 1 becomes even faster. Note that when the third level L3 is selected, the normal speed is achieved.

[0056] The hydraulic pump control unit 343 acquires a current value corresponding to the current amount of operation of the control lever from the operation amount / current value correspondence data corresponding to the level selected by the operator. For example, if the operator selects the first level L1, the hydraulic pump control unit 343 acquires a current value corresponding to the current amount of operation of the control lever from the operation amount / current value correspondence data DT1.

[0057] As described above, the parameters PM1, PM2, PM3 set corresponding to each level have parameter values ​​according to the magnitude of change in the current value relative to the amount of operation of the control lever 20L. Here, as shown in Fig. 4, the current value relative to the amount of operation of the control lever 20L changes significantly in a section where the amount of operation of the control lever 20L is relatively small (for example, up to α1), and thereafter the current value increases gradually. Then, when the amount of operation of the control lever 20L exceeds, for example, αn, the change in the current value becomes large again.

[0058] In this way, the change in the current value relative to the amount of operation of the control lever 20L differs greatly depending on the amount of operation of the control lever 20L in the operation amount / current value correspondence data DT1, DT2, DT3 corresponding to each level. To accommodate this, the parameters PM1, PM2, PM3 have parameter values ​​that correspond to the change in the amount of operation of the control lever 20L in the operation amount / current value correspondence data corresponding to each level, i.e., the change in the current value.

[0059] Specifically, the parameter PM1 set to the first level L1 has a parameter value PM11 corresponding to a section (referred to as the first section) in which the operation amount of the operating lever 20L is, for example, up to the operation amount α1 in FIG. 4, a parameter value PM12 corresponding to a section (referred to as the second section) in which the operation amount of the operating lever 20L exceeds the operation amount α1 in FIG. 4 up to the operation amount αn, and a parameter value PM13 corresponding to a section (referred to as the third section) in which the operation amount of the operating lever 20L exceeds, for example, the operation amount αn in FIG. 4.

[0060] Moreover, the parameter PM2 set to the second level L2 has a parameter value PM21 corresponding to the first section of the operation amount of the operating lever 20L, a parameter value PM22 corresponding to the second section, and a parameter value PM23 corresponding to the third section. Moreover, the parameter PM3 set to the third level L3 has a parameter value PM31 corresponding to the first section, a parameter value PM32 corresponding to the second section, and a parameter value PM33 corresponding to the third section.

[0061] It should be noted that these parameters P11 to P13, parameters P21 to P23, and parameter values ​​P31 to P33 are not shown in the drawing. In this way, by performing filtering using the parameter values ​​set for each section of the amount of operation of the operating lever 20L, that is, the parameter values ​​according to the change in the current value, more appropriate filtering can be performed.

[0062] Fig. 5 is a flowchart illustrating the operation control process in the work vehicle operation control system 30A according to embodiment 1. As shown in Fig. 5, first, when the operator selects a level from the selection screen 331 (see Fig. 3) of the display unit 33 (step S11), the level determination unit 342 determines which of the first level L1 to third level L3 the selected level is (step S12).

[0063] Here, if it is determined that the level selected by the operator is the first level L1, the process proceeds to steps S13 to S15. That is, the hydraulic pump control unit 343 acquires a current value corresponding to the current amount of operation of the operating lever 20L from the operation amount / current value correspondence data DT1 corresponding to the first level L1 (step S13). Then, the hydraulic pump control unit 343 performs a filter process (step S14) using the parameter PM1 on the current value acquired from the operation amount / current value correspondence data DT1.

[0064] In addition, in the filtering process using parameter PM1 in step S14, filtering is performed using parameter values ​​PM11, PM12, and PM13 corresponding to the magnitude of change in the current value relative to the amount of operation of operating lever 20L. By performing such filtering, for example, in a section where the change in the current value is large, abrupt changes in the current can be suppressed.

[0065] Then, the travel speed is controlled by the filtered current value (step S15). Specifically, the process of step S15 controls the amount of pressure oil discharged from the hydraulic pump by the current value corresponding to the amount of operation of the operating lever 20L at the current time. By controlling the amount of pressure oil discharged from the hydraulic pump 31, the hydraulic motor 32 is controlled, and the travel speed of the work vehicle 1 is controlled. In this case, because the first level L1 has been selected by the operator, the work vehicle 1 can be made to travel at a travel speed corresponding to the first level L1.

[0066] Here, if the level selected by the operator remains at the first level L1, each time the operator changes the amount of operation of the control lever 20L, the work vehicle 1 will travel at a vehicle speed that generally corresponds to the current value shown by the dashed line in Fig. 4. For this reason, when the operator selects the first level L1, even if the amount of operation of the control lever 20L is the same, the work vehicle 1 can be caused to travel at a speed limited to a lower speed compared to the normal speed (the speed when the third level L3 is selected).

[0067] The above is the process when the operator selects the first level L1 from the selection screen 331 of the display unit 33. If the operator selects the second level L2 from the selection screen 331 here, in step S12, the level determination unit 342 determines that the selected level is the second level L2, and performs the processes of steps S16 to S18.

[0068] That is, the hydraulic pump control section 343 acquires a current value corresponding to the current amount of operation of the operating lever 20L from the operation amount-current value correspondence data DT2 corresponding to the second level L2 (step S16). After that, a filtering process using the parameter PM2 is performed (step S17). Note that in the filtering process using the parameter PM2 in step S17, filtering process is performed using the parameter values ​​PM21, PM22, and PM23 corresponding to the magnitude of the change in the current value.

[0069] Then, the travel speed is controlled by the filtered current value (step S18). In this case, since the second level L2 has been selected by the operator, the work vehicle 1 can be caused to travel at a travel speed corresponding to the second level L2.

[0070] Here, if the level selected by the operator remains at the second level L2, each time the operator changes the amount of operation of the control lever 20L, the work vehicle 1 travels at a speed change that generally corresponds to the current value shown by the dashed dotted line in Figure 4. For this reason, when the operator selects the second level L2, even if the amount of operation of the control lever 20L is the same, the work vehicle 1 can be caused to travel at a speed limited to a slightly lower speed than the normal speed (the speed when the third level L3 is selected).

[0071] Furthermore, if the operator selects the third level L3 from the selection screen 331 of the display unit 33, in step S12, the level determination unit 342 determines that the selected level is the third level L3, and performs the processes of steps S19 to S21.

[0072] That is, the hydraulic pump control section 343 acquires a current value corresponding to the current amount of operation of the operating lever 20L from the operation amount / current value correspondence data DT3 corresponding to the third level L3 (step S19). After that, a filtering process using the parameter PM3 is performed (step S20). Note that in the filtering process using the parameter PM3 in step S20, filtering process is performed using the parameter values ​​PM31, PM32, and PM33 corresponding to the magnitude of the change in the current value.

[0073] Then, the traveling speed is controlled by the filtered current value (step S21). In this case, since the third level L3 has been selected by the operator, the work vehicle 1 can be caused to travel at a normal traveling speed.

[0074] Here, if the level selected by the operator remains at the third level L3, each time the operator changes the amount of operation of the control lever 20L, the work vehicle 1 will travel at a speed change that generally corresponds to the current value shown by the solid line in Figure 4. In this way, when the operator selects the third level L3, the work vehicle 1 can be caused to travel at a normal speed.

[0075] If the operator changes the selected level while the work vehicle 1 is traveling at the selected level, control immediately switches to control using the current value corresponding to the changed level. For example, if the first level L1 is selected from the selection screen 331 while the work vehicle 1 is traveling at a speed of the third level L3, control immediately switches to control using the current value of the first level L1.

[0076] For this reason, if the operator sets the first level L1 while the work vehicle 1 is operating at a normal speed, the work vehicle immediately switches to the speed of the first level L1. Conversely, if the operator selects the third level L3 while the work vehicle 1 is traveling at a speed based on the current value corresponding to the first level L1, the work vehicle 1 immediately switches to the speed of the third level L3 (normal speed). In this way, the work vehicle 1 immediately switches to the changed speed, allowing for efficient work.

[0077] The processing of steps S11 to S21 described with reference to the flowchart in FIG. 5 can be applied not only to the forward travel of the work vehicle 1, but also to the reverse travel of the work vehicle 1.

[0078] As described above, according to the work vehicle operation control system 30A of embodiment 1, the operator can simply select a level according to his / her skill level and the type of work from the selection screen 331 displayed on the display unit 33, and the work vehicle 1 can be driven at a speed limited to the speed corresponding to the selected level.

[0079] For example, when the first level L1 is selected, even if the amount of operation of the operation lever 20L is the same, the work vehicle 1 travels in a state limited to a speed lower than the normal traveling speed (the traveling speed at the third level L3). Also, when the second level L2 is selected, even if the amount of operation of the operation lever 20L is the same, the work vehicle 1 travels in a state limited to a speed slightly lower than the normal traveling speed (the traveling speed at the third level L3).

[0080] In other words, the sensitivity of the operating lever 20L (the response speed when the operating lever 20L is operated) when the operator selects the first level L1 or the second level L2 is lower than the sensitivity of the operating lever 20L in the normal case (when the third level L3 is selected). Therefore, even an operator who is inexperienced in operating a work vehicle can drive the work vehicle 1 with ease. Also, even an operator who is highly skilled in operating the work vehicle 1 can operate the work vehicle 1 with ease in situations where the work vehicle 1 needs to be driven carefully.

[0081] Furthermore, in the work vehicle operation control system 30A according to the first embodiment, the current value is filtered using a parameter for suppressing changes in the current value. As a result, for example, in a section where the current value changes greatly, abrupt changes in current can be suppressed, allowing the work vehicle 1 to travel smoothly.

[0082] In particular, the degree of increase in the current value is large immediately after the operating lever 20L begins to be tilted from the neutral position. For this reason, by providing a parameter that can suppress a sudden change in the current value in this section, it is possible to suppress a sudden increase in speed when the work vehicle 1 starts moving from a stopped state.

[0083] In this way, by filtering the current value using a parameter for suppressing sudden current changes, it is possible to smooth the travel of the work vehicle 1. However, even without filtering, it is possible to perform basic control such as limiting the travel speed of the work vehicle in accordance with the operator's skill and the type of work, and causing the work vehicle to travel at the limited travel speed.

[0084] [Embodiment 2] Next, a working vehicle motion control system 30B according to the second embodiment will be described. In the working vehicle motion control system 30B according to the second embodiment, the "motion control of the operating unit" is a motion speed control of the working device that controls the motion speed of the working device 14 of the working vehicle 1. Here, the motion speed control of the working device 14 is assumed to be a motion speed control when operating an attachment such as a bucket (not shown). In addition, the above-mentioned "n levels from the first level to the nth level" are assumed to be three levels, namely, a first level L1, a second level L2, and a third level L3. In addition, the working device 14 is assumed to be operated by an operating lever 20R provided on the right side of the operator seat 17 of the working vehicle 1. Hereinafter, the working vehicle motion control system 30B according to the second embodiment will be described.

[0085] Fig. 6 is a diagram showing the configuration of a working vehicle motion control system 30B according to embodiment 2. In the working vehicle motion control system 30B according to embodiment 2, as shown in Fig. 6, the hydraulic pump 31 controls the hydraulic cylinder 19. Also, in the working vehicle motion control system 30B according to embodiment 2, a selection screen 333 for selecting a desired level according to the operator's skill or the work content is displayed on the display unit 33 (see Fig. 7). First, the selection screen 333 displayed on the display unit 33 will be described, and then the other components such as the control device 34 will be described.

[0086] FIG. 7 is a diagram showing an example of a selection screen 333 displayed on the display unit 33. The selection screen 333 shown in FIG. 7 is basically the same as the selection screen 331 shown in FIG. 3. As shown in FIG. 7, a level selection button 334L or a level selection button 334R is displayed on the selection screen 333. By touching the level selection button 334L or the level selection button 334R with a finger, any one of the first level L1 to the third level L3 can be selected. Note that the method of selection when any one of the first level L1 to the third level L3 is the same as the selection screen 331 shown in FIG. 3. In FIG. 7, a state in which the first level is selected is shown.

[0087] The operator selects a desired level according to his / her skill or the work content from the selection screen 333 shown in Fig. 7. For example, if the operator wishes to operate the attachment at a slow speed, the first level L1 is selected. If the operator wishes to operate the attachment at a medium speed, the second level L2 is selected. If the operator wishes to operate the attachment at a normal speed, the third level L3 is selected. As a result, the attachment operates at a speed limited to the selected level, which will be described later.

[0088] Next, the control device 34 will be described with reference to Fig. 6. Basically, like the working vehicle motion control system 30A according to the first embodiment, the control device 34 has a display control unit 341, a level determination unit 342, and a hydraulic pump control unit 343. Here, the display control unit 341 exchanges information with the display unit 33. The level determination unit 342 determines which of the first level L1 to third level L3 the level selected from the selection screen 333 displayed on the display unit 33 is.

[0089] Moreover, the hydraulic pump control unit 343 acquires a current value corresponding to the current amount of operation of the operating lever from the "operation amount / current value correspondence data DT1, DT2, DT3" described in the working vehicle operation control system 30A of the first embodiment, and controls the amount of pressure oil discharged from the hydraulic pump 31 based on the acquired current value. In this case, the pressure oil discharged from the hydraulic pump 31 controls the hydraulic cylinder 19 for operating the attachment. Note that a description of the operation amount / current value correspondence data DT1, DT2, DT3 will be omitted in the working vehicle operation control system 30B of the second embodiment. However, in the working vehicle operation control system 30B of the second embodiment, the operation amount of the "operation amount / current value correspondence data DT1, DT2, DT3" is the operation amount of the operating lever 20R.

[0090] Also, the hydraulic pump control unit 343 filters the current value using a filter in which parameters PM1, PM2, PM3 for suppressing changes in the current value are set, similar to the work vehicle motion control system 30A according to embodiment 1. Note that the parameters PM1, PM2, PM3 are parameters set corresponding to each level, and these parameters PM1, PM2, PM3 have parameter values ​​according to the magnitude of change in the current value in the operation amount / current value correspondence data DT1, DT2, DT3 corresponding to each level, similar to the work vehicle motion control system 30A according to embodiment 1.

[0091] That is, as described in the work vehicle operation control system 30A of embodiment 1, the parameter PM1 has a parameter value PM11 corresponding to the first section (the section up to the operating amount α1 in FIG. 4), a parameter value PM12 corresponding to the second section (the section beyond the operating amount α1 to the operating amount αn in FIG. 4), and a parameter PM13 corresponding to the third section (the section beyond the operating amount αn in FIG. 4).

[0092] Similarly, the parameter PM2 has parameter values ​​PM21, PM22, and PM23 corresponding to the first, second, and third intervals. Similarly, the parameter PM3 has parameter values ​​PM31, PM32, and PM33 corresponding to the first, second, and third intervals.

[0093] 8 is a flowchart explaining the operation control processing in the work vehicle operation control system 30B according to embodiment 2. The operation control processing in the work vehicle operation control system 30B according to embodiment 2 is basically the same as the operation control processing in the work vehicle operation control system 30A according to embodiment 1.

[0094] The operation control process in the work vehicle operation control system 30B of embodiment 2 differs from the operation control process in the work vehicle operation control system 30A of embodiment 1 in that operation control of the working implement 14 (operation speed control of the attachment) is performed, and other processes are similar to the operation control process in the work vehicle operation control system 30A of embodiment 1. Therefore, in the flowchart shown in Figure 8, steps that perform the same processes as in the flowchart shown in Figure 5 are given the same reference numerals (reference numerals S11, S12, ..., etc.).

[0095] The following describes the operation control process in the work vehicle operation control system 30B according to embodiment 2. In the operation control process in the work vehicle operation control system 30B according to embodiment 2, the operation speed of the working device 14 is controlled in step S31 following steps S13 and S14. The operation speed of the working device 14 is also controlled in step S32 following steps S16 and S17. The operation speed of the working device 14 is also controlled in step S33 following steps S19 and S20.

[0096] For example, when the operator selects the first level L1 from the selection screen 333, the hydraulic pump control unit 343 acquires a current value corresponding to the current amount of operation of the operating lever 20R from the operation amount / current value correspondence data DT1 corresponding to the first level L1 (step S13). The hydraulic pump control unit 343 also performs a filtering process (step S14) on the current value acquired from the operation amount / current value correspondence data DT1 using the parameter PM1. In step S14, filtering is performed using the parameter values ​​PM11, PM12, and PM13, as in the first embodiment.

[0097] Then, the operating speed of the working implement 14 is controlled by the filtered current value (step S31). Specifically, in the process of step S31, the amount of pressure oil discharged from the hydraulic pump 31 is controlled by the current value corresponding to the current amount of operation of the control lever 20R. As described above, the operating speed control of the working implement 14 refers to the operating speed control when operating the attachment. Therefore, by controlling the amount of pressure oil discharged from the hydraulic pump 31, the hydraulic cylinder 19 is controlled, and thereby the operating speed of the attachment is controlled. In this case, since the first level L1 has been selected by the operator, the attachment can be operated at an operating speed corresponding to the first level L1.

[0098] Here, if the level selected by the operator remains at the first level L1, each time the operator changes the amount of operation of the control lever 20R, the attachment operates at a speed that generally corresponds to the current value shown by the dashed line in Fig. 4. Therefore, when the operator selects the first level L1, even if the amount of operation of the control lever 20R is the same, the attachment can be operated at a speed limited to a lower speed compared to the normal speed (the speed when the third level L3 is selected).

[0099] The above is the process when the operator selects the first level L1 from the selection screen 331 of the display unit 33. If the operator selects the second level L2 from the selection screen 333, the processes of steps S16, S17 and step S32 are performed. In this case, since the second level L2 has been selected by the operator, the attachment can be operated at an operating speed corresponding to the second level L2.

[0100] Here, if the level selected by the operator remains at the second level L2, each time the operator changes the amount of operation of the control lever 20R, the attachment operates at a speed that generally corresponds to the current value shown by the dashed dotted line in Fig. 4. Therefore, when the operator selects the second level L2, even if the amount of operation of the control lever 20L is the same, the attachment can be operated at a speed limited to a slightly lower speed than the normal speed (the speed when the third level L3 is selected).

[0101] Furthermore, if the operator selects the third level L3 from the selection screen 333, the processes of steps S19, S20 and S33 are performed. In this case, since the third level L3 has been selected by the operator, the attachment can be operated at a normal speed.

[0102] Here, if the level selected by the operator remains at the third level L3, each time the operator changes the amount of operation of the control lever 20R, the attachment operates at a speed that generally corresponds to the current value shown by the solid line in Fig. 4. In this way, when the operator selects the third level L3, the attachment can be operated at the normal speed.

[0103] It should be noted that in the work vehicle operation control system 30B according to the second embodiment, when the operator changes the selected level, the current value immediately switches to the current value corresponding to the changed level. For example, when the operator selects the first level L1 while the attachment is operating at the speed of the third level L3 (normal speed), the control immediately switches to the current value of the first level L1.

[0104] For this reason, if the operator sets the first level L1 while the attachment is operating at the normal speed, the attachment immediately switches to the speed of the first level L1. Conversely, if the operator selects the third level L3 while the attachment is operating at a speed based on the current value corresponding to the first level L1, the attachment immediately switches to the speed of the third level L3 (normal speed). In this way, the attachment immediately switches to the changed speed, allowing for efficient work.

[0105] As described above, according to the work vehicle operation control system 30B of embodiment 2, by simply performing a simple operation such as selecting a level according to the operator's skill and the work content from the selection screen 333 displayed on the display unit 33, the attachment can be operated at a speed limited to the speed corresponding to the selected level.

[0106] For example, when the first level L1 is selected, even if the amount of operation of the control lever 20R is the same, the attachment operates in a state limited to a lower speed than the normal operating speed (operating speed at the third level L3). Also, when the second level L2 is selected, even if the amount of operation of the control lever 20R is the same, the attachment operates in a state limited to a slightly lower speed than the normal operating speed (operating speed at the third level L3).

[0107] In other words, the sensitivity of the operating lever 20R (the response speed when the operating lever 20R is operated) when the operator selects the first level L1 or the second level L2 is lower than the sensitivity of the operating lever 20R in the normal case (when the third level L3 is selected). Therefore, even an operator who is inexperienced in operating a work vehicle can operate the attachment with ease. Also, even an operator who is highly skilled in operating the work vehicle 1 can operate the attachment with ease in situations where it is necessary to operate the attachment carefully.

[0108] Also in the second embodiment, by filtering the current value using a parameter for suppressing the current change, it is possible to suppress abrupt current changes, for example, in sections where the current value changes greatly. This makes it possible to smooth the operation of the attachment. However, even without filtering, it is possible to perform basic control such as limiting the operating speed of the attachment according to the skill of the operator and the type of work, and operating the attachment at the limited operating speed.

[0109] [Embodiment 3] Next, a working vehicle operation control system 30C according to a third embodiment will be described. The work vehicle motion control system 30C according to the third embodiment is a work vehicle motion control system for enabling the work vehicle 1 to maintain its straight-line running ability. That is, even though the operator is operating the work vehicle 1 to drive it straight, the work vehicle 1 may turn in a direction unintended by the operator. In such a case, the work vehicle motion control system 30C according to the third embodiment performs control to maintain the work vehicle 1's straight-line running ability.

[0110] The straight-line running ability of the work vehicle 1 may be impaired, for example, when one of a pair of left and right crawlers is more heavily worn than the other crawler. Straight-line running ability may also be impaired when soil or sand stored in the bucket is significantly unevenly distributed in the left and right direction within the bucket.

[0111] Here, the control for maintaining the straight-line running of the work vehicle 1 individually controls the running speed of each of the pair of left and right traveling devices, i.e., the left traveling device 12L and the right traveling device 12R, of the work vehicle 1. In the following explanation, the running speed control of the left traveling device 12L will be referred to as "left traveling speed control" and the running speed control of the right traveling device 12R will be referred to as "right traveling speed control."

[0112] In the working vehicle operation control system 30C according to the third embodiment, ten levels from level 1 to level 10 are set as left levels for the travel speed of the left-side traveling device 12L, and ten levels from level 1 to level 10 are set as right levels for the travel speed of the right-side traveling device 12R.

[0113] Fig. 9 is a diagram showing the configuration of a working vehicle motion control system 30C according to embodiment 3. As shown in Fig. 9, the working vehicle motion control system 30C according to embodiment 3 includes a hydraulic pump 31, a left hydraulic motor 32L and a right hydraulic motor 32R driven by pressure oil discharged from the hydraulic pump 31, a display unit 33 that displays a selection screen 336 (see Fig. 10) that allows the operator to select one of a plurality of levels, and a control device 34 having a hydraulic pump control unit 343 that controls the hydraulic pump 31 based on the level selected by the operator. First, the selection screen 336 displayed on the display unit 33 will be described, and then the other components such as the control device 34 will be described.

[0114] 10 is a diagram showing an example of a selection screen 336 displayed on the display unit 33. The selection screen 336 is displayed on the display unit 33, which allows the travel speeds of the left traveling device 12L and the right traveling device 12R to be set in multiple stages.

[0115] As described above, ten levels from level 1 to level 10 are set as left levels for the travel speed of the left traveling device 12L. In the following description, the ten left levels are described as "left level L1 to left level L10". In addition, ten levels from level 1 to level 10 are set as right levels for the travel speed of the right traveling device 12R. In the following description, the ten right levels are described as "right level L1 to right level L10".

[0116] 10, for example, when selecting the travel speed of the left traveling device 12L, the left level L1 is set by touching the left level selection button 337L once, the left level L2 is set by touching the left level selection button 337L twice, and the left level L3 is set by touching the left level selection button 337L three times.

[0117] In this way, the travel speed of the left traveling device 12L can be set in 10 stages from left level L1 to left level L10 by touching the left level selection button 337L a number of times. Note that Fig. 10 shows a case where the left level L2 is selected. At this time, the display segments of the left level L1 and the left level L2 are lit up.

[0118] The operating speed of the right traveling device can be selected in the same manner. In this case, the running speed of the right traveling device 12R can be set in 10 stages from right level L1 to right level L10 by the number of times the right level selection button 337R is touched.

[0119] Next, a description will be given of the control device 34. The control device 34 in a work vehicle motion control system 30C according to the third embodiment has a display control unit 341, a level determination unit 342, and a hydraulic pump control unit 343, as shown in FIG.

[0120] The display control unit 341 exchanges information with the display unit 33. The level determination unit 342 determines which level selected from the selection screen 336 is among the left level L1 to left level L10, and also determines which level selected from the selection screen 336 displayed on the display unit 33 is among the right level L1 to right level L10.

[0121] The hydraulic pump control unit 343 has "left level-current value corresponding data" in which a current value is set corresponding to each of the 10 left levels (left level L1 to left level L10), and also has "right level-current value corresponding data" in which a current value is set corresponding to each of the 10 right levels. In Fig. 9, the left level-current value corresponding data and the right level-current value corresponding data are collectively described as "level-current value corresponding data DT30". However, when describing the left level-current value corresponding data and the right level-current value corresponding data, the left level-current value corresponding data will be described as "left level-current value corresponding data 30L" and the right level-current value corresponding data will be described as "right level-current value corresponding data 30R".

[0122] In the left level / current value correspondence data 30L, current values ​​I1 to I10 are set corresponding to the left levels L1 to L10, respectively. Similarly, in the right level / current value correspondence data 30R, current values ​​I1 to I10 are set corresponding to the right levels L1 to L10, respectively.

[0123] When a predetermined level is selected from the left levels L1 to L10, the hydraulic pump control unit 343 acquires a current value corresponding to the selected level from the left level / current value correspondence data 30L. Then, based on the acquired current value, the hydraulic pump control unit 343 controls the discharge amount of pressure oil for driving the left hydraulic motor 32L for the hydraulic pump 31. In this case, the left hydraulic motor 32L is controlled by controlling the discharge amount of pressure oil from the hydraulic pump 31.

[0124] Furthermore, when a predetermined level is selected from the right levels L1 to L10, the hydraulic pump control unit 343 acquires a current value corresponding to the selected level from the right level / current value correspondence data 30R. Then, based on the acquired current value, the hydraulic pump control unit 343 controls the amount of pressure oil discharged from the hydraulic pump 31 to drive the right hydraulic motor 32R. In this case, the right hydraulic motor 32R is controlled by controlling the amount of pressure oil discharged from the hydraulic pump 31.

[0125] Here, the current values ​​for the left traveling device 12L are set in ascending or descending order from the left level L1 to the left level L10. In the working vehicle operation control system 30C according to the third embodiment, the current values ​​for the left traveling device 12L are set in descending order. That is, the current values ​​I1 to I10 corresponding to each of the left level L1 to the left level L10 are controlled so as to become smaller as the level increases. The current values ​​for the right traveling device are also set in descending order from the right level L1 to the right level L10. That is, the current values ​​I1 to I10 corresponding to each of the right level L1 to the right level L10 are controlled so as to become smaller as the level increases.

[0126] For example, the left level will be taken as an example. Here, for ease of understanding, the current values ​​corresponding to each of the left levels L1 to L10 are assumed to decrease by 10% in descending order from the current value during normal driving (current value of 100%). That is, the current value 1I of the left level L1 is 90% of the current value during normal driving, the current value 12 of the left level L2 is 80% of the current value during normal driving, and so on, decreasing in descending order by 10%. The same is true for the right level, where the current value decreases in descending order by 10% in descending order from the current value I1 during normal driving. Note that, although the case where the current value decreases by 10% in descending order is illustrated here, the current value is not limited to 10%.

[0127] In this way, the current values ​​corresponding to each of the left level L1 to left level L10 and the current values ​​corresponding to each of the right level L1 to right level L10 are set in descending order, so that the current value becomes smaller as each level increases by one step.

[0128] The hydraulic pump control unit 343 controls the amount of pressure oil discharged from the hydraulic pump 31 based on the current value that has been subjected to the current control as described above. For example, if the left level L1 is set on the selection screen 336, the amount of pressure oil discharged from the hydraulic pump 31 is controlled at a current value that is 10% less than the current value for normal speed (which is assumed to be a current value of 100%). This controls the left hydraulic motor 32L, and the speed of the left traveling unit 12L becomes slower than that of the right traveling unit 12R by the amount that the current value is 10% less. Therefore, the work vehicle 1 turns slightly to the left.

[0129] Furthermore, if the right level L7 is set on the selection screen 336, the discharge amount of pressure oil from the hydraulic pump 31 is controlled at a current value that is 70% less than the current value for normal speed (which is assumed to be a current value of 100%). This controls the right hydraulic motor 32R, and the speed of the right traveling unit 12R becomes slower than that of the left traveling unit 12L by the amount that the current value is 70% less. Therefore, the work vehicle 1 will make a large turn to the right.

[0130] In the above example, the current value changes at an equal rate at each level, that is, the current value changes linearly between the left level L1 and the left level L10 and between the right level L1 and the right level L10, but the current value is not limited to this. For example, the current value at each level may be set so that the current value changes between the left level L1 and the left level L10 and between the right level L1 and the right level L10 along an exponential curve. As an example, the current value may change so that the current value decreases significantly from the left level L1 to a predetermined level and from the right level L1 to a predetermined level along a relatively steep curve, and then decreases gradually along a gentle curve.

[0131] Moreover, the hydraulic pump control unit 343 performs PID control so that the travel speed of the left traveling device 12L and the travel speed of the right traveling device 12R become speeds corresponding to the selected levels. Specifically, a target value corresponding to each level is set for the rotation speed of the left hydraulic motor 32L. Then, the hydraulic pump 31 is controlled so that the rotation speed of the left hydraulic motor 32L becomes the set target value. A target value corresponding to each level is also set for the rotation speed of the right hydraulic motor 32R. Then, the hydraulic pump 31 is controlled so that the rotation speed of the right hydraulic motor 32R becomes the set target value. By performing such PID control, it is possible to reduce deviation from the target value when the work vehicle 1 changes its traveling direction, and to make it possible to turn along a more accurate trajectory.

[0132] Fig. 11 is a flowchart explaining the operation control process in the working vehicle operation control system 30C according to embodiment 3. The control of the working vehicle operation control system 30C according to embodiment 3 will be explained with reference to Fig. 11. First, a case will be explained where the working vehicle 1 is turning right for some reason while the operator is trying to drive the working vehicle 1 straight. Note that at this time, the operation lever is assumed to be in the straight-ahead driving state.

[0133] First, when the operator selects a level from the selection screen 336 (see FIG. 10) (step S41), the level determination unit 342 determines whether the level selected by the operator is left level L1 to left level L10 (step S42). In this case, because the work vehicle 1 is turning right, the operator selects one of left level L1 to left level L10. Therefore, in step S42, it is determined that the level selected by the operator is one of left level L1 to left level L10. Here, it is assumed that the operator selects left level L1 on the selection screen 336.

[0134] Next, it is determined whether the operation of the operating lever 20L is forward or backward (step S43). If the result of the determination in step S43 is forward or backward, a current value control corresponding to the selected level is performed on the left traveling device 12L (step S44). In this case, since the left level L1 is selected, the "current value control corresponding to the level" in step S44 is set to a current value that is, for example, 10% less than the current value for normal speed (current value of 100%). In addition, PID control is performed together with the current value control in step S44 (step S45). As described above, the PID control controls the rotation speed of the left hydraulic motor 32L to a target value. Then, the left traveling speed control is performed by the current value control and the PID control (step S46).

[0135] In this way, left-side traveling speed control is performed by current value control and PID control. In this left-side traveling speed control, the current value is set 10% lower than that of the right-side traveling device 12R by current value control, so the speed is slower by that amount. As a result, the work vehicle 1 that is turning right changes course to travel left. Furthermore, by performing PID control in addition to current value control, it is possible to reduce deviation from the target value when the work vehicle 1 changes direction to the left, and to turn along a more accurate trajectory.

[0136] By performing the processing of steps S41 to S46, the work vehicle 1 that is turning to the right can change its traveling direction to the left. This makes it possible to correct the traveling direction. When correcting the traveling direction, the operator can appropriately change the level on the selection screen 336 while judging the degree of correction of the traveling direction. For example, if the attempt to correct the traveling direction results in too little turning, the level is appropriately increased to observe how the turning proceeds. Conversely, if the attempt to correct the traveling direction results in too much turning, the level is appropriately decreased to observe how the turning proceeds.

[0137] On the other hand, when the work vehicle 1 is turning left, the traveling direction can be corrected in a similar manner. In this case, the operator selects one of the right level L1 to right level L10 from the selection screen 336. Therefore, in step S42, it is determined that it is not the left level L1 to left level L10, and the process proceeds to step S47.

[0138] In step S47, it is determined whether the level selected by the operator is one of the right levels L1 to L10. Here, it is assumed that the operator has selected the right level L7 on the selection screen 336. Next, it is determined whether the operation of the operating lever 20L is for forward or reverse (step S48).

[0139] If the result of the determination in step S48 is forward or reverse, current value control corresponding to the selected level is performed on the right-side traveling device 12R (step S49). In this case, since the right level L7 is selected, the "current value control corresponding to the level" in step S49 sets a current value that is 70% less than the current value for normal speed (current value of 100%). Furthermore, PID control is performed together with the current value control in step S49 (step S50). As described above, the PID control controls the rotation speed of the right-side hydraulic motor 32R to a target value. Then, right-side traveling speed control is performed by the current value control and the PID control (step S51).

[0140] In this way, right-side traveling speed control is performed by current value control and PID control. In this case, the right-side traveling speed control is performed by current value control, which sets the current value 70% lower than that of the left-side traveling device 12R, so the speed is slower by that amount. As a result, the work vehicle 1 that is turning left changes course to travel rightward. Furthermore, by performing PID control in addition to current value control, it is possible to reduce deviation from the target value when the work vehicle 1 changes direction to the right, and to turn along a more accurate trajectory.

[0141] By performing the processing of steps S41, S42, and S47 to S51, the work vehicle 1 that is turning left can change its traveling direction to the right. This makes it possible to correct the traveling direction. When correcting the traveling direction, the operator can appropriately change the level on the selection screen 336 while judging the degree of correction of the traveling direction. For example, if the turning is too small as a result of attempting to correct the traveling direction, the level is appropriately increased and the state of the turning is observed. Conversely, if the turning is too large as a result of attempting to correct the traveling direction, the level is appropriately decreased and the state of the turning is observed.

[0142] Incidentally, in step S42 in the flowchart shown in Fig. 11, if it is determined that the level selected by the operator is not the left level L1 to the left level L10, and in step S47, it is determined that the level selected by the operator is not the right level L1 to the right level L10, the process proceeds to step S52. In step S52, the process for maintaining straightness is invalidated, and the process returns to step S42. Also, in steps S43 and S48, if it is determined that the operating lever 20L is not in the forward or reverse position, the process for maintaining straightness is invalidated, and the process returns to step S42.

[0143] As described above, according to the work vehicle operation control system 30C according to the third embodiment, it is possible to maintain the straightness of the work vehicle 1 when the straightness of the work vehicle 1 is impaired. Moreover, the operation for maintaining the straightness of the work vehicle 1 can be performed by simply selecting an appropriate level displayed on the selection screen 336 while determining the travel direction of the work vehicle. Therefore, even an operator who is unfamiliar with operating this type of work vehicle can easily perform the operation for maintaining the straightness of the work vehicle 1.

[0144] Furthermore, in the work vehicle operation control system 30C according to the third embodiment, PID control is performed in addition to current value control, thereby making it possible to reduce deviation from a target value and turn along a more accurate trajectory when the work vehicle 1 changes direction. However, it is possible to perform basic control such as maintaining the straightness of the work vehicle 1 even without PID control.

[0145] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit and scope of the present invention. For example, the following modifications are also possible.

[0146] (1) The display unit 33 shown in Figures 3, 7 and 10 shows a case where the selection screens 331, 333, and 336 displayed in each embodiment are displayed separately. However, this is not limited to this. For example, the selection screens 331, 333, and 336 displayed in each embodiment can also be displayed on one and the same screen. This allows the various settings described in each embodiment to be made from one selection screen.

[0147] (2) In the first embodiment, the magnitude of the current value when the operation amount of the operating lever 20L is the same is set in ascending order from the first level L1 to the third level L3 as shown in Fig. 4. However, this is not limited to this, and the reverse may also be true. In other words, the magnitude of the current value when the operation amount of the operating lever 20L is the same may be set in descending order from the first level L1 to the third level L3. In this case, the work vehicle 1 travels at the slowest speed at the third level L3, and travels at the fastest speed (normal speed) at the first level L1.

[0148] (3) In the second embodiment, the magnitude of the current value when the operation amount of the operating lever 20R is the same is set in ascending order from the first level L1 to the third level L3 as shown in FIG. 4. However, this is not limited to this, and the reverse may also be true. That is, the magnitude of the current value when the operation amount of the operating lever 20R is the same may be set in descending order from the first level L1 to the third level L3. In this case, the attachment operates at the slowest speed at the third level L3, and at the fastest speed (normal speed) at the first level L1.

[0149] (4) In the first and second embodiments, the selectable levels are three stages, the first level L1 to the third level L3, but the number of selectable levels is not limited to three, and more levels may be selectable. However, in consideration of ease of use for the operator and ease of control, it is preferable that the number of levels is in the range of 2≦n≦5, for example, when n (n is a positive integer).

[0150] (5) In the third embodiment, the current values ​​corresponding to the left level L1 to the left level L10 change in descending order from the left level L1 to the left level L10. That is, the current values ​​corresponding to the left level L1 to the left level L10 change in a manner that the higher the level, the smaller the current value becomes. However, this is not limited to the above, and the opposite may also be true. That is, the current values ​​corresponding to the left level L1 to the left level L10 may change in ascending order. In this case, the current value becomes larger as the level increases. The same is true for the right level L1 to the right level L10.

[0151] (6) In the third embodiment, the left level and the right level each have 10 levels, but the number of levels is not limited to 10. However, even in this case, in consideration of ease of use for an operator and ease of control, it is preferable that the number of levels is in the range of, for example, 5≦n≦15, where n is a positive integer. [Explanation of symbols]

[0152] 1···Work vehicle, 11···Main frame, 12···Traveling gear, 12L···Left-side traveling gear, 12R···Right-side traveling gear, 14···Working gear, 15···Cabin, 17···Operator seat, 18···Arm, 19···Hydraulic cylinder, 20(20L, 20R)···Operation lever, 30A, 30B, 30C···Motion control system for work vehicle, 31···Hydraulic pump, 32···Hydraulic motor, 32L···Left-side hydraulic motor, 32R···Right-side hydraulic motor, 33 ···Display unit, 34··Control device, 331, 333, 336···Selection screen, 332L, 334L, 337L···Level selection button on the left side, 332R, 334R, 337R···Level selection button on the right side, 341···Display control unit, 342···Level determination unit, 343···Hydraulic pump control unit, DT1, DT2, DT3···Operation amount·Current value corresponding data, L1 to L3···1st level to 3rd level, L1 to L10···Left 1st level to left 10th level (right 1st level to right 10th level)

Claims

1. A motion control system for a work vehicle that controls a hydraulic pump based on a current value output by operation of an operating lever, thereby controlling a motion of a motion unit, n levels (n is an integer of 2 or more) from a first level to an n-th level are set for the operating speed when the operating unit operates, A hydraulic pump; a display unit that displays a selection screen for allowing an operator to select one of the n levels; A control device having a hydraulic pump control unit that controls the hydraulic pump based on the level selected by the operator; Equipped with The hydraulic pump control unit includes: a current value limiting step of limiting the amount of pressurized oil discharged by the hydraulic pump based on the ...

2. 2. The working vehicle motion control system according to claim 1, The operation control of the operation unit is a travel speed control for controlling a travel speed of a travel device of the work vehicle, and n levels from a first level to an n-th level are set for the travel speed of the travel device, a hydraulic motor for traveling driven by the pressure oil discharged from the hydraulic pump; The hydraulic pump control unit includes: a current value corresponding to the current amount of operation of the control lever at the current point in time is obtained from the operation amount / current value correspondence data corresponding to the level selected by the operator, and the amount of pressurized oil discharged by the hydraulic pump is controlled based on the obtained current value.

3. 2. The working vehicle motion control system according to claim 1, The operation control of the operation unit is an operation speed control of a work device that controls the operation speed of a work device of the work vehicle, and n levels from a first level to an n-th level are set for the operation speed of the work device, a hydraulic cylinder driven by pressure oil discharged from the hydraulic pump; The hydraulic pump control unit includes: a current value corresponding to the current amount of operation of the control lever at the current point in time is obtained from the operation amount / current value correspondence data corresponding to the level selected by the operator, and the amount of pressurized oil discharged by the hydraulic pump is controlled based on the obtained current value.

4. 4. The working vehicle motion control system according to claim 2, a current value corresponding to the operation amount of the control lever, the current value corresponding to the operation amount of the control lever being set in ascending or descending order from the first level to the nth level,

5. 4. The working vehicle motion control system according to claim 2, the hydraulic pump control unit filters the current value using a filter in which a parameter for suppressing a change in the current value is set corresponding to each level; A work vehicle operation control system, wherein the parameter has a value according to a magnitude of change in current value in the operation amount / current value correspondence data corresponding to each of the levels.

6. 2. The working vehicle motion control system according to claim 1, The operation control of the operation unit is a left side travel speed control for controlling the travel speed of the left side travel device of the pair of left and right travel devices possessed by the work vehicle, and a right side travel speed control for controlling the travel speed of the right side travel device of the pair of left and right travel devices possessed by the work vehicle, wherein n levels from a first level to an nth level (n is an integer of 2 or more) are set as a left level for the travel speed of the left side travel device, and n levels from a first level to an nth level are set as a right level for the travel speed of the right side travel device, the display unit displays a selection screen for allowing an operator to select one of the n left levels and the n right levels; A left hydraulic motor and a right hydraulic motor are driven by pressure oil discharged from the hydraulic pump, The hydraulic pump control unit includes: a left level-current value correspondence data in which a current value is set corresponding to each of the n left levels, and a right level-current value correspondence data in which a current value is set corresponding to each of the n right levels, a current value corresponding to a level selected by the operator from the n-stage left level is obtained from the left level / current value correspondence data, and a discharge amount of pressure oil for driving the left hydraulic motor is controlled for the hydraulic pump based on the obtained current value; A current value corresponding to a level selected by the operator from the n-stage right level is acquired from the right level / current value correspondence data, and the amount of pressure oil discharged from the hydraulic pump for driving the right hydraulic motor is controlled based on the acquired current value. A work vehicle motion control system comprising:

7. 7. The working vehicle motion control system according to claim 6, a current value set corresponding to each level of the left level / current value correspondence data and each level of the right level / current value correspondence data being set in ascending or descending order from a first level to an nth level,

8. 8. The working vehicle motion control system according to claim 6, The hydraulic pump control unit further performs PID (Proportional Integral Derivative) control so that the travel speed of the left traveling device and the travel speed of the right traveling device each become speeds corresponding to the selected level.

9. 9. The working vehicle motion control system according to claim 8, The PID control is setting target values ​​corresponding to each level for the rotation speed of the left hydraulic motor and the rotation speed of the right hydraulic motor, and controlling the hydraulic pump so that the rotation speed of the left hydraulic motor and the rotation speed of the right hydraulic motor become the set target values; A work vehicle motion control system comprising:

Images