JP5851360B2 - Work vehicle - Google Patents

Description

  The present invention relates to a work vehicle in which a ground work device that is subjected to rolling control is connected to a vehicle body.

  In order to smoothly perform ground work while traveling along the contour line on a sloping ground, ground work is performed based on the detection value of the sensor that detects the tilt angle in the left-right direction of the work vehicle and the setting value set by the tilt setting device. A work vehicle including an inclined land rolling control means for automatically rolling control of an apparatus is known from Patent Document 1, for example. In this work vehicle, when the slope value mode is selected, the rotary tilling device, which is the ground work device, is subjected to rolling control so as to match the slope angle of the sloped land by the action of the sloped land rolling control means. That is, when the work vehicle travels linearly along the contour line of the sloping ground, a linear tillage work following the inclination of the inclined surface is performed. By repeating such a traveling along the contour line while making a U-turn, the tilling work on the entire slope is completed. At that time, at the time of a U-turn on an inclined ground or during other turns, the inclination angle serving as a reference in the inclination rolling control is suddenly changed, so that the control followability is deteriorated. For this reason, in the work vehicle according to Patent Document 1 described above, when the steering angle of the front wheels exceeds the right or left set angle, the tilt rolling control is interrupted, and the ground work is performed by greatly raising the rotary tillage device from the ground. (Refer to paragraph number [0063] of Patent Document 1).

JP 2010-172299 A (paragraph number [0034-0067], FIG. 6)

However, in order to improve work efficiency, there is a demand for continuous work without raising the ground work device even when making a U-turn or other turning in ground work on an inclined ground. However, in a work vehicle equipped with a conventional ground control device that is subjected to rolling control, the reference tilt angle used in the inclined ground rolling control is the vehicle body angle at the time when the ground work device is lowered to the ground, and the tilt measured thereafter. The reference tilt angle is corrected based on the angle. At that time, in order to avoid the reference tilt angle from being changed undesirably due to local fluctuations, it is necessary to increase the time constant and to make the measurement value smooth (blunt). However, the smoothing (smoothing, blunting) of the measurement value due to such a large time constant causes a large error between the actual inclination angle and the reference inclination angle during U-turns or other turns where a large change in inclination angle occurs. (Delay) will occur. In order to reduce this error (delay), if the time constant is reduced, the reference inclination angle is unnecessary in response to sudden changes in the inclination angle due to unevenness of the ground even in straight running where the inclination angle hardly changes. This causes a disadvantage that sensitive rolling control is performed.
Therefore, there is a demand for a technique that enables highly accurate slope rolling control even in turning such as a U-turn.

A work vehicle according to the present invention, in which a ground work device to be controlled in rolling is connected to a vehicle body, an actuator for rolling the ground work device with respect to the vehicle body, a rolling angle detector for detecting a rolling angle, Steering behavior information acquisition unit for acquiring steering behavior information indicating the behavior of the straight running posture and the turning posture, and the value obtained by performing the smoothing process on the value based on the detection value from the rolling angle detector Based on the steering behavior information, the angle reference value calculation unit for the value and the smoothing characteristics used for the smoothing process when traveling on an inclined ground of the vehicle body are more in the turning posture than in the straight running posture. An annealing characteristic changing unit that changes the annealing strength to be weak, and a rolling control value for the actuator is generated based on the angle reference value and the detected value. And a rolling control value generation unit, the smoothing process is the of this intensity filter process to filter strength, the angle reference value said that we strength increases to the input of the detection value rapidly The angle reference value is slowly changed with respect to the input of the detected value when the annealing intensity is reduced .

  In this configuration, from the steering behavior information acquired by the steering behavior information acquisition unit, whether the work vehicle that is working is in a straight traveling posture or a turning posture, more specifically, from a straight traveling posture to a turning posture. It is possible to detect whether the vehicle has transitioned or has shifted from a turning posture to a straight traveling posture. As a result, when the angle reference value is obtained during turning work traveling, an annealing process using an annealing characteristic having weaker annealing strength than that during straight traveling work traveling is executed. As a result, the angle reference value used for the tilt rolling control during the turning work travel reflects the value of the detected value group of the rolling angle detector detected immediately before. Therefore, an error (delay) between the actual inclination angle and the reference inclination angle is suppressed, and an inclined ground-to-ground work adapted to a sudden change in the inclination angle that occurs during a U-turn or other turn is realized. Further, when returning from the turning work traveling to the straight traveling working traveling, the annealing characteristics are returned to those having strong annealing strength, so that stable conventional ground-to-ground work is ensured.

When the work vehicle shifts from the straight traveling posture to the turning posture, that is, when the shift of the work vehicle from the straight traveling posture to the turning posture is detected, the inclination angle associated with traveling tends to change slowly at the beginning. Conversely, when a shift from the turning posture of the work vehicle to the straight-ahead posture is detected, initially, the variation in the inclination angle associated with traveling tends to increase. Therefore, when shifting from the turning posture to the straight running posture, it is preferable to delay the timing at which the annealing strength once weakened in the turning posture is increased again. Therefore, in one of the preferred embodiments of the present invention, when the work vehicle shifts from the straight traveling posture to the turning posture, the smoothing characteristic changing unit steers from the turning posture to the straight traveling posture. At the time of transition to the straight running posture in the returning behavior, the smoothing strength is maintained in a state lower than the smoothing strength at the straight running posture.
As a more specific configuration for this, the annealing characteristic changing unit maintains the annealing strength in the turning posture for a predetermined time after the shift to the straight running posture is determined in the steering return behavior. It is proposed to adopt the configuration.

  In order to achieve controllable annealing characteristics, it is advantageous to use a time constant. By increasing the time constant, the influence of the measured value of the tilt angle obtained immediately before the control or the calculated value obtained from this measured value on the finally calculated angle reference value is reduced. Therefore, as one specific embodiment, in the present invention, the annealing strength of the annealing characteristic is a time constant, and the time constant in the straight running posture is a predetermined value between 3 seconds and 5 seconds. It is proposed that the time constant in the turning posture has a characteristic that the time constant becomes smaller as the turning posture deviates from the straight running posture, and takes a value between 0.1 second and 2 seconds.

  In addition, even if the work vehicle during work travel is intended to travel in a straight line, there is a situation where the steering behavior slightly shows the tendency of the turning posture due to an intentional steering operation or an unexpected steering operation or slip. In such a situation, it is inconvenient to change the annealing characteristics. For this reason, although a dead zone is set, as one of the preferred embodiments at that time, the smoothing characteristic changing unit may set the turning posture of 15% to 30% of the maximum turning posture as the dead zone. Proposed.

Various types of steering behavior information can be used for detecting the attitude of the work vehicle during work travel, that is, the straight running attitude and the turning attitude.
One suitable form is turning angle information representing the turning angle of the steering wheel. Since the turning angle of the steering wheel directly leads to a change in the traveling direction of the work vehicle, it is possible to reliably detect whether the work vehicle is in a straight traveling position or a turning posture by repeatedly detecting this cutting angle. .

  Further, when the work vehicle is equipped with a GPS and / or direction sensor, it is possible to easily acquire the direction information indicating the traveling direction of the vehicle body. Therefore, azimuth information indicating the traveling azimuth of the vehicle body is also a preferred form of steering behavior information.

  Furthermore, it is also preferable that the steering behavior information is turning angle information that represents the turning angle of the steering wheel and traveling speed information that represents the traveling speed of the vehicle body. In this case, the turning radius and turning time of the vehicle body can be calculated from the turning angle of the steered wheel and the traveling speed, and the additional advantage of adjusting the annealing strength according to the calculated turning radius and turning time is obtained. It is done. As a specific configuration for realizing this form, a plurality of tables representing the relationship between the cut angle and the annealing strength are prepared, and it is proposed as a simple configuration that a table to be used is selected according to the traveling speed Is done.

It is a schematic diagram explaining the principle of sloping ground rolling control by this invention. It is a whole side view of a tractor and a rotary tiller. It is a top view which shows the boarding operation part of a tractor. It is a perspective view which shows the rear part of a tractor and a rotary tillage apparatus. It is a block diagram which shows the input / output with respect to a control unit. It is a functional block diagram of the sloping ground rolling control part built in a control unit. It is a top view of a hydraulic operation panel. It is a type chart figure which shows inclination rolling control. It is a filter characteristic diagram showing the time constant which changes based on a cut angle. It is a graph which shows an experimental result. FIG. 10 is an enlarged view of the second turning work traveling area.

Before explaining a specific embodiment of the working vehicle of the present invention, the principle of the rolling control of the inclined ground adopted in the present invention will be described with reference to FIG.
In this sloped land rolling control, a work vehicle in which the ground work device to be controlled for rolling is connected to the vehicle body continues the ground work by the ground work device not only when traveling straight ahead but also when turning. As can be understood from FIG. 1, in order to perform ground work along an inclined surface having a predetermined slope inclination angle, the inclination angle of the work vehicle (which may be the inclination angle of the ground work device) is detected and the inclination is related. Based on the detected angle, it is necessary to obtain an angle reference value (which becomes a zero point in the sloped land rolling control) that substantially matches the sloped slope angle. At this time, the angle reference value is obtained by subjecting the tilt measurement value measured at a predetermined repetition frequency to a smoothing process on the calculated value obtained by the preprocessing performed as necessary. This annealing process can be generally regarded as an arithmetic process using a time constant, but other arithmetic processes may be used. In the sloped land rolling control of the present invention, the value of the annealing strength used for the annealing process when the work vehicle is considered to be traveling straight and when the work vehicle is considered to be turning. Are different, and a strong annealing strength is used in a straight running posture and a weak annealing strength is used in a turning posture. Here, since the rolling control is handled, the inclination angle of the work vehicle or the ground work device is hereinafter treated as the rolling angle.

  For this reason, the work vehicle according to the present invention includes a preprocessing function, an angle reference value calculation function, an annealing characteristic change function, and a control signal generation function. The pre-processing function performs a processing operation on the detected value of the rolling angle and outputs a calculated value, and can be expressed as “F (detected value) → calculated value”. The angle reference value calculation function outputs a value obtained by subjecting the calculated value to the smoothing process as an angle reference value, and can be expressed as “N (calculated value, smoothing intensity) → angle reference value”. it can. The annealing characteristic change function changes the annealing characteristic used for the annealing process based on the value of steering behavior information (steering behavior value). “G (steering behavior value) → annealing strength” Can be expressed as The control signal generation function generates a control signal for an actuator that causes the ground work device to roll with respect to the vehicle body based on the calculated angle reference value and the sequentially obtained calculation value. Angle reference value) → control signal ”. As an example of a relational expression for deriving the control value for rolling: H (calculated value, angle reference value), the control value is generated based on the inclination deviation calculated by comparing the angle reference value with the calculated value. Relational expressions or tables are proposed.

  Changing the annealing characteristic means changing the value of the annealing strength. Taking the time constant as an example, increasing the annealing strength means increasing the value of the time constant. To weaken is to reduce the value of the time constant. The determination as to whether the work vehicle is regarded as a straight running posture or a turning posture is performed based on steering behavior information indicating the behavior of the vehicle body from the straight running posture to the turning posture and the behavior from the turning posture to the straight running posture. As the steering behavior information, the turning angle of the steering wheel can be used (G (cutting angle) → smoothing strength), but the traveling direction of the vehicle body using a direction sensor or the like may be used (G ( Other information may be used, such as (reference azimuth−traveling azimuth) → annealing intensity). When the turning angle is adopted, the straight angle is regarded as a straight running posture at a turning angle within a certain range, the angle reference value is calculated with a strongly set annealing strength, and the turning posture is considered weak in the region close to the maximum turning angle. The angle reference value is calculated by the annealing intensity. The intermediate turning angle is regarded as an intermediate turning posture, and the annealing strength obtained by proportional calculation can be used.

  Steering behavior information can also be turning angle information that represents the turning angle of the steering wheel and traveling speed information that represents the traveling speed of the vehicle body. Speed) → Annealing strength) ”. Since the turning radius and turning time of the vehicle body can be calculated from the turning angle of the steered wheel and the traveling speed, the above formula can be expressed by “G (cutting angle, turning radius) → smoothing strength)” or “G (cutting angle). , Turning time) → annealing strength) ”. In this way, when there are a plurality of parameters, it can be easily realized by adopting a configuration in which a table created by other parameters is selected and used according to one parameter.

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 2, the work vehicle in this embodiment is a tractor equipped with a rotary tiller 15 as a ground work device that is subjected to rolling control. The rotary tiller 15 is connected to the vehicle body of the tractor via a lifting mechanism 4 capable of rolling control.

  As shown in FIG. 1, an engine 11 is mounted on the front part of a vehicle body supported by a pair of left and right front wheels 1a and a pair of left and right rear wheels 1b, and a transmission 3 is arranged at the rear part of the vehicle body. This tractor is a four-wheel drive type, and is provided with a front wheel differential device 13 that transmits power from the transmission 3 to the front wheels and a rear wheel differential device 14 that transmits the power to the rear wheels.

  The steering unit 2 shown in FIG. 2 is provided with a pair of left and right brake pedals 23 that can independently or commonly brake the steering handle 21, the driver's seat 22, and the left and right rear wheels 1b that steer the front wheels 1a. . An elevating lever 24 is disposed on the front side on the right side of the driver seat 22. The turning angle of the front wheel 1 by the steering handle 21 (steering angle from the straight-ahead position to the right or the steering angle from the straight-ahead position to the left) is detected by the turning angle sensor 31. The elevating lever 24 can be held at an arbitrary operating position, and the operating position of the elevating lever 24 is detected by a position sensor 24a.

  The elevating mechanism 4 connects the rotary tiller 15 to the tractor vehicle body so that the elevating control and the rolling control are possible. As shown in FIGS. 2 and 4, the lifting mechanism 4 includes a top link 41, a pair of left and right lower links 42, a pair of left and right lift arms 43, a lift cylinder 44, a rolling cylinder 46, and a linkage rod 45. One end of the top link 41 and the lower link 42 is connected to the vehicle body, in this embodiment, to the rear portion of the housing 3a of the transmission 3 via a bracket so as to be swingable up and down. The other ends of the top link 41 and the lower link 42 are connected to the rotary tiller 15. The lift arm 43 is connected to the upper part of the housing 3a so as to be swingable up and down. The lift cylinder 44 is a single-acting cylinder that swings the lift arms 43 up and down. The rolling cylinder 46 is a double-acting cylinder having one end connected to the right lift arm 43 and the other end connected to the right lower link 42. The linkage rod 45 connects the left lift arm 43 and the left lower link 42. The vertical angle of the lift arm 43 with respect to the tractor body is detected by an angle sensor 43a.

  A rear cover 15a is attached to the rotary tiller 15 so as to be swingable up and down. The rear cover 15a is biased downward by a spring 15b, and the swing angle of the rear cover 15a corresponds to the tilling depth of the rotary tiller 15. This swing angle is detected by the angle sensor 15c.

  With the above structure, when the left and right lift cylinders 44 are expanded and contracted, the left and right lift arms 43 swing, and as a result, the rotary tiller 15 moves up and down. Further, when the rolling cylinder 46 is expanded and contracted, the rolling adjustment of the rotary tiller 15 with the left lower link 42 as a fulcrum is performed. That is, in this embodiment, the rolling cylinder 46 functions as an actuator that causes the rotary tiller 15 to roll with respect to the tractor vehicle body.

  Control of the rotary tiller 15 is performed by the control unit 5. The control unit 5 is a computer unit called an ECU, and can realize various functions by starting a program. Examples of such functions are a position control function, a first elevation control function, a second elevation control function, a draft control function, a rolling control function, an auto up control function, a backup control function, and a manual rolling operation function.

  As shown in FIG. 5, the input port of the control unit 5 includes a sensor group other than the lift lever position sensor 24 a, the rear cover angle sensor 15 c, the lift arm angle sensor 43 a, and the cutting angle sensor 31 described above. An inclination sensor 32, a rotation speed sensor 33, a traction load sensor 34, a stroke sensor 35, and the like are connected. The inclination sensor 32 functions as a rolling angle detector that detects the rolling angle of the tractor vehicle body (the inclination angle of the tractor vehicle body in the left-right direction). The rotation speed sensor 33 detects the rotation speed of the engine 11. The traction load sensor 34 detects the traction load applied to the base portions of the left and right lower links 42. The stroke sensor 35 detects the tilt angle in the left-right direction of the rotary tiller 15 with respect to the tractor vehicle body by detecting the expansion / contraction length of the rolling cylinder 46.

  Various control operation devices equipped in the tractor are connected to the control unit 5, but only the output signal system for the lifting mechanism 4 is shown in FIG. 5. Here, a lift control valve 44a for the lift cylinder 44 and a rolling control valve 46a for the rolling cylinder 46 are connected to the control unit 5 via a hydraulic control module 81 that generates a control signal for hydraulic equipment. .

  Next, the hydraulic operation panel 6 will be described with reference to FIG. An operation signal from the hydraulic operation panel 6 is transmitted to the control unit 5 via the operation ECU 82 connected to the control unit 5 through the in-vehicle LAN (see FIG. 5). As shown in FIG. 3, the hydraulic operation panel 6 is provided on the right side of the driver seat 22. The hydraulic operation panel 6 includes a tilling depth adjustment dial 60, a work changeover switch 61, a rolling changeover switch 62, a rolling angle adjustment dial 63, a drop speed adjustment dial 64, a sensitivity adjustment dial 65, a height restriction dial 66, and a first rolling manual. A switch 67a, a second rolling manual switch 67b, a parallel return switch 67c, an auto up switch 68, a backup switch 69, and an inclined turning rolling permission switch 70 are arranged.

The plowing depth adjustment dial 60 sets a desired plowing depth with this dial. Turning the dial in the “shallow” direction decreases the tilling depth, and turning it in the “deep” direction increases the tilling depth. In the case of a draft, set the towing load.
A desired work can be selected from “auto”, “E auto”, “draft”, and “laser” by the work changeover switch 61. “Auto” is used when the rear cover 15a senses the tilling depth and performs auto work. “E auto” is used when auto work is performed with the rear cover 15a raised. “Draft” is used when drafting. “Laser” is used for work with a laser working machine. At this time, the lamp 61a assigned to the selected work is turned on.

The rolling changeover switch 62 can select one of three horizontal modes and an inclined land mode. The horizontal mode is used when the rotary tiller (ground work device) 15 is always kept horizontal or at a constant angle with respect to the ground regardless of the inclination of the tractor body. At that time, when the rotary tiller 15 is raised to the vicinity of the upper end, the inclined posture of the work implement is returned to and held in a position parallel to the vehicle body. The three horizontal modes are provided corresponding to the three-point link mounting state (lower link width / mounting hole position) of the lifting mechanism 4.
In the sloping land mode, slant rolling control is executed, and control is performed so that the rotary tiller 15 is tilted along the ground at the time of tilling work on the sloping land. In this embodiment, the function of adjusting the inclination of the rotary tiller 15 to the inclination of the ground is also executed by automatically correcting the amount of the tractor sinking to the valley side with respect to the inclination change of the tractor.
When the rolling changeover switch 62 is turned off, the horizontal control is canceled and “manual” is set. As a result, the rotary tiller 15 stops at the position moved by the first rolling manual switch 67a and the second rolling manual switch 67b, and the position is maintained. That is, the rotary tiller 15 returns to the original position even if it expands or contracts due to a leak or the like.
The rolling angle adjustment dial 63 is used when the horizontal mode is selected by the rolling changeover switch 62 and sets a control target angle of the rotary tiller 15. The lift cylinder 44 contracts when the rolling angle adjustment dial 63 is turned in the “lower left” direction, and extends when it is turned “lower right”.

  The drop speed adjustment dial 64 is used to adjust the drop speed of the elevating mechanism 4. The sensitivity adjustment dial 65 is used to adjust the amount of movement of the lower link 42 with respect to a change in load. The contents differ depending on the set work type. For example, in “auto”, the dead band width of the rear cover 15a is adjusted. In “E auto”, the width of the detected rotation speed of the engine rotation sensor 33 is adjusted. In the “draft”, the amount of movement of the lower link 42 with respect to the amount of change in the towing load and the load sensitivity are adjusted. In “laser”, the amount of movement of the lower link 42 with respect to the sensor signal is adjusted. The height restricting dial 66 is used when changing the ascent upper limit position of the elevating device 4, thereby restricting the ascending position to an arbitrary height when the rotary tiller 15 is raised.

  The first rolling manual switch 67 a is used when the lift cylinder 44 is extended, and the second rolling manual switch 67 b is used when the lift cylinder 44 is contracted. The lift cylinder 44 operates only when the first rolling manual switch 67a or the second rolling manual switch 67b is being pressed. When the rolling changeover switch 62 is “horizontal”, operating this switch releases the automatic control and activates the rolling safety lock. Further, when the first rolling manual switch 67a or the second rolling manual switch 67b is “OFF”, the lift cylinder 44 performs position control for maintaining the length thereof. When the rolling changeover switch 62 is “horizontal” and the rolling manual switches 67a and 67b are operated to operate the safety lock function, the automatic control is restored by operating the parallel return switch 67c. When the rolling changeover switch 62 is “OFF” (position control), when the parallel return switch 67c is pressed, the return control is executed so that the three-point link of the lifting mechanism 4 is in parallel with the tractor.

  When the backup switch 69 is set to “ON”, the corresponding lamp 69a is lit, and when it is set to reverse, the rotary tiller 15 is automatically raised. When the auto up switch 68 is set to “ON”, the corresponding lamp 68a is turned on, and when the front wheel turning angle is set to the set angle or more with the steering handle 21, the rotary tiller 15 is automatically raised.

  The tilt turning rolling permission switch 70 continues the ground work without raising the rotary tiller 15 even if the tractor turns while performing the ground work on the slope, and also continues the slope rolling control. That is, a command to cancel the command is given by the auto up switch 68. Instead of providing the tilt turning rolling permission switch 70, the “up” setting of the auto up switch 68 may be used as a substitute for the tilt turning rolling permission switch 70.

Next, the contents of the above-described control function realized by a program in the control unit 5 will be described.
The position control function is such that the right and left lift cylinders 44 are simultaneously expanded and contracted by the control valve 44a so that the vertical angle of the right and left lift arms 43 becomes the vertical angle corresponding to the operating position of the lift lever 24. The vertical height of the rotary tiller 15 is controlled.
In this case, as shown in FIG. 5, the highest position A1 of the lift lever 24 corresponds to the mechanical upper limit of the right and left lift arms 43, and the lowest position A2 of the lift lever 24 is the right and left lift arms 43. Corresponds to the mechanical lower limit. When the threshold position is set in advance slightly below the highest position A1 of the lifting lever 24, and the lifting lever 24 is operated in a range between the lowest position A2 and the threshold position, the rotary tiller 15 is moved to. Power transmission is permitted, and when the elevating lever 24 is operated in a range between the set position and the highest position A1, power transmission to the rotary tiller 15 is prohibited.

  The first raising / lowering control function is configured to extend and retract the right and left lift cylinders 44 by the control valve 44a so that the vertical angle of the rear cover 15a of the rotary tiller 15 is maintained at the set angle. The height is controlled to be constant. By operating the tilling depth adjustment dial 60, the set depth is changed to the "shallow" and "depth" sides.

  The second lift control function detects the load applied to the engine 11 based on the detection value of the rotation speed sensor 33, and the right and left lifts are controlled by the control valve 44a so that the load applied to the engine 11 is maintained at the set value. The engine load control is performed to move the rotary tiller 15 up and down by extending and retracting the cylinder 44.

  In the draft control function, the detected value of the traction load sensor 34 is maintained at the set value in a state where a plow (not shown) is connected to the top link 41 and the right and left lower links 42 instead of the rotary tiller 15. As described above, the control valve 44a performs traction load control in which the right and left lift cylinders 44 are expanded and contracted to raise and lower the plow.

  The rolling control function controls the control valve 46a so that the horizontal inclination angle of the rotary tiller 15 with respect to the detected horizontal plane (horizontal mode) or inclined plane (inclination mode) is maintained at the set value of the rolling angle adjustment dial 63. Thus, the rolling cylinder 46 is controlled to extend and contract. At that time, by detecting the expansion / contraction length of the rolling cylinder 46 by the stroke sensor 35, the horizontal inclination angle of the rotary tiller 15 with respect to the tractor vehicle body is detected. Further, the tilt sensor 44 detects the tilt angle of the tractor vehicle body in the left-right direction with respect to the horizontal plane. When the slope mode is selected by the rolling changeover switch 62, the reference angle of the inclined surface is calculated by a method described in detail later based on the inclination angle detected by the inclination sensor 44. The reference angle of the inclined surface corresponds to an angle of a horizontal plane in the horizontal mode, that is, an inclination angle of 0 degrees, and is generally obtained by an average calculation of detected inclination angles.

  The manual rolling operation function lowers the right or left side of the rotary tiller 15 in preference to the rolling control function. This operation is realized by extending or contracting the rolling cylinder 46 only while pushing the first rolling manual switch 67a or the second rolling manual switch 67b. When the pressing operation of the first rolling manual switch 67a or the second rolling manual switch 67b is finished, the rolling control function is restored. At that time, by pushing the parallel return switch 67c, the rolling cylinder 46 expands and contracts so that the rolling cylinder 46 has the same length as the linkage rod 45 (the rotary tiller 15 is in parallel with the tractor body). .

  The rolling control function includes not only a horizontal ground rolling control function but also an inclined ground rolling function. This slope rolling function is realized by slope rolling control that operates through the execution of the slope rolling control module 50 that is program-installed in the control unit 5. In this inclined land rolling control, the ground work by the rotary tiller 15 is continued not only when traveling straight ahead but also during turning. In the functional block diagram shown in FIG. 7 and the time chart shown in FIG. 8, the running is introduced in the present invention in order to perform ground work while performing rolling control even when turning on an inclined ground. The calculation of the angle reference value that is the estimated inclination angle of the ground will be described.

  As illustrated in FIG. 7, the sloped land rolling control module 50 includes a steering behavior information acquisition unit 51, a preprocessing unit 52, an angle reference value calculation unit 53, an annealing characteristic change unit 55, and a deviation calculation unit 56. The rolling control value generation unit 57 is provided.

  The steering behavior information acquisition unit 51 acquires steering behavior information indicating the behavior of the tractor vehicle body from the straight running posture to the turning posture and the behavior from the turning posture to the straight running posture. In this embodiment, the steering angle sensor Based on the detection signal from 31, a turning angle representing the real-time traveling posture of the tractor vehicle body is output.

The preprocessing unit 52 performs a processing calculation on the detection value from the tilt sensor 32 and outputs a calculation value representing the tilt angle of the tractor vehicle body. As the tilt sensor 32, there are an angle sensor alone based on a spirit level or a combination of an angle sensor and an acceleration sensor, but the type of the tilt sensor 32 is not particularly limited in the present invention. So they deal with them in common. In the combination of the angle sensor and the acceleration sensor, each detection value is pre-calculated in the pre-processing unit 52, and the calculated value as the calculation result is output as a value representing the inclination angle of the tractor vehicle body. If the tilt sensor 32 is attached to the rotary tiller 15 instead of the tractor body, the angle of the tilt sensor 32 is corrected by using the angle of the rotary tiller 15 with respect to the tractor body, thereby An inclination angle is required.
The basic function of the preprocessing unit 52 is to calculate a moving average of detection values from the tilt sensor 32. For example, assuming that the detection sampling interval of the tilt sensor 32 is 0.01 second, a moving average of 0.5 seconds, that is, 50 moving averages is calculated.

  The angle reference value calculation unit 53 outputs a value obtained by subjecting the calculation value sent from the preprocessing unit 52 to a smoothing process as an angle reference value. The angle reference value is an inclination angle that becomes a reference in running on an inclined ground, and is recalculated and adjusted based on the sequentially detected inclination angles. In this annealing process, a group of calculation values input over time is processed according to the annealing characteristics. In this embodiment, a filter processing unit 54 based on the principle of time constant is mounted as an annealing processing unit that performs this annealing process. Therefore, if the smoothing characteristic used in the filter processing unit 54, that is, the time constant is increased, the adjustment of the angle reference value by the sequentially detected inclination angle is delayed.

In this embodiment, the annealing characteristic changing unit 55 implemented as a changing unit changes a time constant (annealing characteristic: annealing strength) used in the filter processing unit (annealing processing unit) 54. The annealing characteristic (filter characteristic) changing unit 55 changes the time constant used by the filter processing unit 54 based on the turning angle input from the steering behavior information acquiring unit 51 when the tractor body travels on an inclined ground. The time constant when the tractor vehicle body is in a turning posture (cutting angle greater than or equal to a predetermined value) is weaker than the time constant when the tractor vehicle body is in a straight posture (cutting angle less than a predetermined value). This will be explained with a simple example.
Assuming that the current angle reference value is R, the newly input tilt angle is S, the time constant: τ is 2, and the sampling interval: t is 0.01, the newly calculated angle reference value Rc is
Since Rc = (τ * R + t * S) / (τ + t),
Approximately
Rc = (199 * R + 1 * S) / 200 can be used,
If the time constant is 0.5, the newly calculated angle reference value Rc is
The equation Rc = (49 * R + 1 * S) / 50 can be used.
Therefore, if the time constant (annealing strength) is increased, the angle reference value is not changed rapidly, so insensitive rolling control is executed. If the time constant (annealing strength) is decreased, sensitive rolling control is performed. Executed.

  The deviation calculating unit 56 calculates an inclination deviation by comparing the angle reference value calculated by the angle reference value calculating unit 53 with the calculated value indicating the real-time inclination angle output from the preprocessing unit 52. Based on this inclination deviation, the rolling control value generation unit 57 generates a rolling control value for appropriately operating the rolling cylinder 46. The generated rolling control value is sent to the hydraulic control module 81 and used for controlling the rolling control valve 46a.

An example of tilt rolling control by the tilt rolling control module 50 described above will be described with reference to the type chart of FIG. In this example, the tractor goes straight along the contour line (straight running posture), then turns 90 ° (turning posture) and then goes straight again.
The time chart (a) shows the transition of the turning angle. When turning, the steering wheel is operated up to a maximum turning angle of 60 ° and then returned. In the determination of the straight running posture and the turning posture based on the turning angle, the dead zone is set from 0 ° to 10 ° here, and the turning angle between them is regarded as the straight running posture. That is, the turning angle of 10 ° is a threshold value for the turning filter processing in the angle reference value calculation unit 53. In this embodiment, a turning angle of 10 ° or more is regarded as a substantial turning posture. The posture having a turning angle of 10 ° as the threshold value is selected based on the knowledge that a turning angle indicating a turning posture of about 15% to 30% of the maximum turning posture is appropriate as the threshold value.

  FIG. 9 illustrates a filter characteristic (annealing characteristic) diagram representing a time constant that changes based on the cut angle. Here, the time constant is set to 2.0 when the turning angle is between 0 ° and 10 °, and this time constant is used for normal filter processing executed in the straight running posture. When the cutting angle is 40 ° or more, the time constant is set to 0.1, and the time constant between the cutting angle of 10 ° and 40 ° is an interpolation value of 2.0 and 0.1. This interpolation calculation may be a linear expression or a multi-order expression. Alternatively, an arbitrary value obtained experimentally may be used as the interpolation value. When the turning angle is 10 ° or more, the time constant obtained from this filter characteristic is used for the turning filter processing executed in the turning posture.

  The time chart (b) shows the filter processing at the time of turning that rises when the tractor turns from the turning posture to the straight running posture in the steering return behavior to the straight running posture, that is, when the turning angle increases to 10 °. Indicates the start trigger pulse. The time chart (c) shows the stop trigger pulse of the filtering process during turning that rises when the turning angle decreases and reaches 10 °. The time chart (d) is a pulse permitting execution of the turning filter process, and has a time interval from the start trigger pulse to the stop trigger pulse.

  The time chart (e) is a timer pulse that rises during driving of the timer, rises (starts) with a stop trigger pulse, and falls (stops) in a predetermined time, for example, 2 to 3 seconds.

  When turning on a sloping ground and returning from a turning posture to a straight running posture, immediately performing rolling control with a high time constant makes the deviation between the angle reference value and the detected inclination angle unstable, and the rotary tiller The phenomenon that 15 is delayed is observed. For this reason, in this embodiment, immediately after returning from the turning posture to the straight running posture, the transition time filter process having a low time constant (about 0.1 to 1.0) is continued for about 1 second to several seconds. ing. The time chart (f) is a pulse that permits the execution of such a transition filter process, and ends at the falling edge of the timer pulse.

  The time chart (g) is a pulse that permits the execution of the normal filter process when the turn filter process and the transition filter process are being executed.

[Experimental example]
In this experimental example, a tractor equipped with a rotary tiller 15 travels in a straight line along a contour line on a slope at a traveling speed of about 3 km / h, turns 360 degrees in the middle, and travels again in a straight line. ing. FIG. 10 is a graph showing the measurement results obtained in this experiment. In this graph, time (seconds) is set on the horizontal axis, and the sensor value of the tilt sensor 32 (decimal value of 10-bit data) and the turning angle (degree) of the front wheel 1a which is the steering wheel are set on the vertical axis. ing. FIG. 11 is an enlarged view of an area of the second turning work travel in FIG.

In this graph, the thin line is a detected value indicating the inclination angle of the inclination sensor 32, and the thick line is a value indicating the inclination angle obtained by subjecting the detected value to the filtering process during turning and the filtering process during transition. A dotted line shows a time constant (an annealing intensity value). The one-dot chain line indicates the cutting angle of the front wheel 1a. After turning twice with the left-turn handle operation, the left-turn handle operation is returned. The transition time filter processing that lowers the constant time constant when the steering is returned is performed for 1 second with a time constant of 0.5 seconds.
From the graph shown in the figure, in turning work traveling, the filter processing value closely follows the actual measured value of the tilt angle by applying the filter processing during turning and the filter processing during transition to reduce the time constant. I can understand that.

  In the above-described embodiment, the transition time filter process is started when the turning angle is returned to 10 ° which is the start threshold value of the turning time filter process, and is stopped after a predetermined time. You may make it start a process, when it returns to the threshold value different from the start threshold value of the filter process at the time of turning.

  The rolling control of the present invention can be applied not only to a form in which a cultivator is connected to a rotary cultivator as a ground working apparatus, but also to a form in which a plow, a snowplow, or a dozer is connected as a ground working apparatus. For example, the present invention can also be applied to work vehicles such as rice transplanters and combines.

1a: Front wheel 1b: Rear wheel 15: Rotary tillage device (ground work device)
31: Cutting angle sensor 32: Tilt sensor (rolling angle detector)
33: Rotational speed sensor 60
34: Traction load sensor 61
35: Stroke sensor 63
4: Lift mechanism 41: Top link 42: Lower link 43: Lift arm 43a: Angle sensor 44: Lift cylinder 44a: Lift control valve 45: Linking rod 46: Rolling cylinder (actuator)
46a: Rolling control valve 5: Control unit (ECU)
50: Inclination rolling control module 52: Pre-processing unit 51: Steering behavior information acquisition unit 53: Angle reference value calculation unit 54: Filter processing unit (annealing processing unit)
55: Filter characteristic change rear part (annealing characteristic change part)
56: Deviation calculation unit,
6: Hydraulic operation panel 81: Hydraulic control module 82: Operation ECU

Claims (10)

A work vehicle that connects a ground control device that is subjected to rolling control to a vehicle body,
An actuator for rolling the ground work device relative to the vehicle body;
A rolling angle detector for detecting the rolling angle;
A steering behavior information acquisition unit that acquires steering behavior information indicating the behavior of the vehicle body in a straight running posture and a turning posture;
An angle reference value calculation unit having a value obtained by subjecting a value based on a detection value from the rolling angle detector to an angle reference value;
When running on an inclined ground of the vehicle body, the smoothing characteristics used for the smoothing process are changed based on the steering behavior information so that the smoothing strength is weaker in the turning posture than in the straight running posture. An annealing characteristic change part,
A rolling control value generating unit that generates a rolling control value for the actuator based on the angle reference value and the detected value;
Equipped with a,
The annealing process is a filtering process in which the annealing intensity is a filter intensity. When the annealing intensity increases, the angle reference value is rapidly changed with respect to the input of the detection value, and the annealing intensity is A work vehicle configured to slowly change the angle reference value with respect to an input of the detection value when the value becomes smaller .   The smoothing characteristic changing unit maintains a smoothing strength lower than a smoothing strength in the straight running posture when the steering return behavior from the turning posture to the straight running posture is changed to the straight running posture. Item 4. The work vehicle according to Item 1.   The work vehicle according to claim 2, wherein the smoothing characteristic changing unit maintains the smoothing strength in the turning posture for a predetermined time after the shift to the straight running posture is determined in the steering return behavior.   The annealing strength of the annealing characteristic is a time constant, the time constant in the straight running posture is a predetermined value between 2 seconds and 4 seconds, and the time constant in the turning posture is the straight running posture. The work vehicle according to any one of claims 1 to 3, wherein the work vehicle has a characteristic of becoming smaller as it deviates from the range, and takes a value between 0.1 seconds and 2 seconds.   The work vehicle according to any one of claims 1 to 4, wherein the smoothing characteristic changing unit sets a turning posture of 15% to 30% of a maximum turning posture as a dead zone.   The work vehicle according to any one of claims 1 to 5, wherein the steering behavior information is turning angle information representing a turning angle of a steering wheel.   The work vehicle according to any one of claims 1 to 5, wherein the steering behavior information is azimuth information representing a traveling azimuth of a vehicle body.   The work vehicle according to any one of claims 1 to 5, wherein the steering behavior information includes turning angle information indicating a turning angle of a steering wheel and traveling speed information indicating a traveling speed of a vehicle body.   The work vehicle according to claim 8, wherein a plurality of tables representing a relationship between the turning angle and the annealing strength are prepared, and a table to be used is selected according to a traveling speed.   The rolling control value generation unit generates the rolling control value based on an inclination deviation calculated by comparing the angle reference value and a calculated value obtained from the detected value. The work vehicle according to one item.

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