JP3556809B2 - Tractor - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention belongs to the technical field of a tractor having a lift arm.
[0002]
[Prior art]
Generally, a tractor of this type includes a lift arm for raising and lowering a work machine, and automatically controls the lift arm so that the lift arm (or the work machine) maintains a set height (or a set plowing depth). However, in such a case, it is required to set a so-called dead zone in which the operation of the lift arm is stopped until the deviation of the detected position from the target position exceeds the dead zone set value, and to ensure control stability.
[0003]
[Problems to be solved by the invention]
However, in setting the dead zone, if the dead zone setting value is too large, the control accuracy is reduced.If the dead zone setting value is too small, frequent operations cannot be prevented. Therefore, an ambiguous intermediate setting value must be set. In fact, it was not possible to obtain. Therefore, it has been proposed that in the lift arm operating state, good control accuracy is secured by using a small dead band setting value, while in the lift arm stopped state, frequent operation is prevented by using a large dead band setting value. In this device, since it is allowed to stop for a long time in a state where the deviation is located between the small dead zone set value and the large dead zone set value, a control error is tolerated for a long time and the work accuracy is reduced. There was a possibility.
[0004]
[Means for Solving the Problems]
SUMMARY OF THE INVENTION The present invention has been made to solve these problems in view of the above situation, and the invention of claim 1 is a lift arm for raising and lowering a work machine, and automatically controlling the lift arm. A deviation calculating means for calculating a deviation between the target position and the detected position, and an operation command output for outputting a lift arm operation command when the deviation exceeds a dead zone set value. Means, the automatic control unit, when the deviation of the operation stop state exceeds the dead zone set value and within the delay processing range set value, the lift arm operation command until the predetermined timer time has elapsed. per the provided delay processing means for the output restriction, a plurality of delay processing range and sets the multi-stage, by lengthening the extent delay timer time delay processing range close to the dead zone, operating When the deviation of the stop state exceeds the dead band setting value, a tractor, characterized in that to start the counting of the total delay timer. By doing so, when the operation is stopped, the lift arm is maintained in the stopped state unless the deviation exceeds the dead zone set value but does not exceed the delay processing range set value. If this condition lasts for a predetermined period of time, the lift arm is operated toward the dead zone, so that a state outside the dead zone is allowed for a long time. As a result, control accuracy can be improved. When the deviation is small, the delay is long and the stability is emphasized. On the other hand, when the deviation is large, the delay is short and the control accuracy is emphasized. Therefore, the control accuracy is improved while ensuring the stability. be able to. Furthermore, since the delay processing in each delay processing range is canceled based on the time when the deviation deviates from the dead band, absolute delay processing centering on the dead band can be performed. As a result, small fluctuations in the deviation (noise , Etc.), and stable control can be performed. If the deviation greatly fluctuates, the delay processing can be quickly canceled to secure good control accuracy.
The invention according to claim 2 includes a lift arm that raises and lowers the work machine, and an automatic control unit that automatically controls the lift arm, and further includes a deviation calculation that calculates a deviation between a target position and a detected position. Means, and a tractor provided with an operation command output means for outputting a lift arm operation command when the deviation exceeds the dead zone set value, wherein the deviation of the operation stop state exceeds the dead zone set value in the automatic control unit, and When the delay processing range is within the set value, the delay processing means for limiting the output of the lift arm operation command until the predetermined timer time elapses is provided. The delay timer time is set longer for the processing range, and when the deviation of the operation stop state enters each delay processing range, the counting of the corresponding delay timer is started and the current position is determined. When the delay timer time of the delay processing range closer to the dead zone than the delay processing range has elapsed, a tractor, characterized in that to release the delay processing range at least the current position. By doing so, when the operation is stopped, the lift arm is maintained in the stopped state unless the deviation exceeds the dead zone set value but does not exceed the delay processing range set value. If this condition lasts for a predetermined period of time, the lift arm is operated toward the dead zone, so that a state outside the dead zone is allowed for a long time. As a result, control accuracy can be improved. When the deviation is small, the delay is long and the stability is emphasized. On the other hand, when the deviation is large, the delay is short and the control accuracy is emphasized. Therefore, the control accuracy is improved while ensuring the stability. be able to. Furthermore, since the delay processing of each delay processing range is canceled based on the time when the deviation enters each delay processing range, relative delay processing can be performed in each delay processing range, and as a result, deviation fluctuations Can be performed as much as possible, and control with an emphasis on stability can be performed. In addition, in canceling the delay processing of each delay processing range based on the time when the deviation enters each delay processing range, it is possible to prevent the delay time from becoming unnecessarily long and to improve control accuracy. .
According to a third aspect of the present invention, there is provided a lift arm for elevating and lowering the work machine, and an automatic control unit for automatically controlling the lift arm. The automatic control unit further includes a deviation calculation for calculating a deviation between a target position and a detected position. beyond means, in tractor formed by providing an operation command output means for outputting the lift arm operation command when the deviation exceeds the dead band setting value, the automatic control unit, the deviation of a deactivated state of the dead zone setting value, In addition, when the delay processing range is within the set value, the delay processing means for limiting the output of the lift arm operation command until a predetermined timer time elapses is provided. The tractor is characterized in that the delay timer time is set longer for the delay processing range, and the delay processing range closer to the dead zone than the currently located delay processing range is released. By doing so, when the operation is stopped, the lift arm is maintained in the stopped state unless the deviation exceeds the dead zone set value but does not exceed the delay processing range set value. If this condition lasts for a predetermined period of time, the lift arm is operated toward the dead zone, so that a state outside the dead zone is allowed for a long time. As a result, control accuracy can be improved. When the deviation is small, the delay is long and the stability is emphasized. On the other hand, when the deviation is large, the delay is short and the control accuracy is emphasized. Therefore, the control accuracy is improved while ensuring the stability. be able to. Further, the delay processing range closer to the dead zone than the currently located delay processing range is released. That is, when the deviation returns to the delay processing range on the dead zone side, the lift arm is actuated immediately. Therefore, it is possible to prevent the delay time from becoming unnecessarily long and improve control accuracy.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, one embodiment of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 denotes a traveling body of a tractor. A working machine 3 such as a rotary is connected to a rear portion of the traveling body 1 via a lifting link mechanism 2 so as to be able to move up and down. The working machine 3 moves up and down with the vertical swing of a lift arm 5 that suspends the lifting link mechanism 2 via the lift rod 4, while a lift provided on one of the left and right lift rods 4. The rod cylinder 6 inclines left and right as the rod cylinder 6 expands and contracts, but all of these basic configurations are the same as in the past.
[0006]
Reference numeral 7 denotes a lift cylinder that moves the lift arm 5 up and down. The lift cylinder 7 expands and contracts with the valve switching operation of the lift arm electromagnetic switching valve 8, but switches the lift arm electromagnetic switching valve 8. Since the extension solenoid 8a and the reduction solenoid 8b can be intermittently driven based on the inching pulse, the operating speed of the lift cylinder 7 can be controlled based on the duty setting (ON time / cycle) of the inching pulse. It has become.
[0007]
Reference numeral 9 denotes a control unit configured by using a microcomputer. The input side of the control unit 9 includes a lift arm sensor 10 for detecting the position of the lift arm 5, and a plowing depth based on the swing angle of the rear cover 3a. , A position sensor 13 for detecting the operating position of a position lever (working machine-to-machine height setting device) 12, an automatic cultivation depth switch 14 for turning on and off automatic cultivation depth control, an automatic cultivation depth control An input interface circuit includes a tillage setting volume (working machine-to-ground height setting device) 15 for setting a target tillage depth, and a lifting / lowering sensitivity setting switch 16 for setting sensitivity for automatic control of tillage depth according to the type of working machine. On the output side, solenoids 8a and 8b for extending and contracting the electromagnetic switching valve 8 for the lift arm are connected via an output interface circuit. There.
[0008]
Then, in the main routine of the control section 9, after performing "initial setting" for setting an elevating delay timer, resetting an elevating delay timer elapsed flag, resetting an elevating delay range passage flag, and the like, the elevating sensitivity setting is performed. A "sensitivity set" for switching the set time of the up / down delay timer, the width of the up / down delay range, the control mode of the comparison output data set, and the like according to the switching position of the switch 16, and a "position for setting the position target value based on the position sensor value "Control", "Plowing depth control" to set the plowing depth target value based on the plowing depth setting volume value, "Plowing depth setting volume check" to check the operation of the plowing depth setting volume 15, lift arm sensor value and position target value "Position comparison output data set" that outputs a lift arm elevating command according to the deviation from Subroutines such as a "plowing depth comparison output data set" that outputs a lift arm elevating command in accordance with the deviation between the sensor value and the plowing depth target value are repeatedly executed. Hereinafter, among these subroutines, The “tilling depth setting volume check”, “position comparison output data set” (modes 1 to 4) and “tilling depth comparison output data set” (modes 1 to 4) will be described based on the flowchart. Although the comparison data is different between the “position comparison output data set” and the “plow depth comparison output data set”, the basic control concept is almost the same, so the comparison data of the position control must be written in parentheses. The flowchart and description will be shared. Further, since the control concept at the time of the raising operation and the control operation at the time of the lowering operation are substantially the same, the flowchart and the description at the time of the lowering operation are omitted.
[0009]
In the “till depth setting volume check”, the difference between the current till depth setting volume data and the till depth setting storage data in which the till depth setting volume data is stored at predetermined time intervals is calculated, and the calculation result is borrowed ( It is determined whether or not the value is negative, and if the determination is YES, the calculation result is converted into a two's complement number. Then, the operation result is compared with the operation confirmation data, and as a result, if it is determined that the operation result is larger than the operation confirmation data, all the elevation delay range pass flags of the “plow depth comparison output data set” are set. It is supposed to. That is, when the tillage depth setting volume 15 is operated, the lift arm 5 is actuated immediately after the lifting delay process described later is canceled, so that good responsiveness, operability and setting accuracy are ensured when setting the tillage depth. You can do it.
[0010]
In the “comparison output data set (mode 1)”, first, the cylinder operation direction is determined based on the difference between the tillage depth sensor value and the tillage depth target value (the difference between the lift arm sensor value and the position target value). It is determined whether the deviation is out of the dead zone. If the deviation is within the dead zone, after resetting (or clearing) the lifting delay timer, the lifting delay timer elapsed flag, and the lifting delay range passage flag, the lifting stop command is output. If the deviation is out of the dead zone, the descending delay timer, the descending delay timer elapsed flag, and the descending delay range passage flag are reset, and then the ascending side processing is executed. If it is outside the dead zone, the descending side processing is executed after resetting the rise delay timer, the rise delay timer elapsed flag, and the rise delay range passage flag.
[0011]
In the ascending-side process, first, it is determined whether the deviation is within the delay range (1 to 3) or outside the delay range. In other words, a delay range is set in the deviation range adjacent to the dead zone, and in this delay range, the lifting / lowering operation process (lift arm lifting command output) is restricted until a predetermined delay timer expires, while immediately outside the delay range, Since the lifting operation processing is executed, even if the deviation at the time of stopping the operation is out of the dead zone, if the deviation is within the delay range, the lift arm 5 can be kept stopped to prevent frequent lifting operations. When the state continues for a predetermined timer period, the lift arm 5 is operated in the dead zone direction, so that the inconvenience of accepting the state deviating from the dead zone for a long time can be eliminated.
[0012]
The delay range is divided into a plurality of delay ranges 1 to 3 in which range upper limit deviations H1 to H3 (H1 <H2 <H3) differ stepwise, and the delay timer time is set longer as the delay range is closer to the dead zone. ing. That is, if the deviation is relatively small even if it is out of the dead zone, the elevating operation processing is delayed for a long time to prevent frequent elevating operations, while if the deviation is large, the delay processing is canceled at a relatively early stage. As a result, control accuracy is ensured.
[0013]
By the way, in the "comparison output data set (mode 1)", when the deviation is within the dead zone, the delay timers of the respective delay ranges 1 to 3 are cleared (set). When the deviation is out of the dead zone, the delay timer is cleared. Not to run. That is, when the deviation deviates from the dead zone, the counting of all delay timers is started, so that the delay processing of each of the delay ranges 1 to 3 is canceled based on the deviation deviating from the dead zone. Therefore, since the absolute delay processing centered on the dead zone is performed, frequent operation can be prevented by allowing a small fluctuation of the deviation, while the delay processing is quickly canceled when the deviation largely fluctuates. As a result, good control accuracy can be ensured, and as a result, in mode 1, it is possible to execute the plowing depth automatic control (position control) suitable for work in which control accuracy is important.
[0014]
In each of the delay ranges 1 to 3, the elapse of the corresponding delay timer is determined, the delay timer elapse flag is set, and thereafter the delay release state is maintained by referring to the content of the delay timer elapse flag. In each of the delay ranges 1 to 3 and outside the delay range, a delay range passage flag for confirming the passed delay ranges 1 to 3 is set. Then, in the delay range 1, the case where the reduced delay timer 1 has elapsed, the case where the passing flag of the reduced delay range 3 is set, the case where the passing flag of the reduced delay range 2 is set, and the reduced delay timer 2 or 3 Are set, and when the passage flag of the reduced delay range 1 is set and the elapsed flag of the reduced delay timer 2 is set, the reduced delay timer 1 elapsed flag is set. In the delay range 2, when the compressed delay timer 2 has elapsed, when the elapsed flag of the compressed delay timer 1 is set, when the passage flag of the compressed delay range 3 is set, When the passage flag is set and the elapse flag of the reduced delay timer 2 is set, the elapse flag of the reduced delay timer 2 is set. Has elapsed, the elapsed flag of the reduced delay timer 2 has been set, the elapsed flag of the reduced delay timer 1 has been set, and the passage flag of the reduced delay range 3 has been set. Is set to the elapse flag of the contraction delay timer 2. In other words, when the deviation reaches out of the delay range, or when any of the delay ranges is released based on the elapse of the delay timer, all the delay ranges 1 to 3 are released. After the arm 5 is once operated, the raising / lowering operation can be continued until the deviation enters the dead zone regardless of the fluctuation of the deviation.
[0015]
In each of the delay ranges 1 to 3, when the delay timer elapses, the elevating operation process set for each delay range is executed. In the elevating operation process 1, the predetermined minimum drive duty (used duty) is set. (The minimum value of the range). That is, in the delay range 1 close to the dead zone, the lift arm 5 is slowly operated to prevent a so-called hunting phenomenon.
[0016]
On the other hand, when the delay timer elapses in the delay ranges 2 and 3, the drive duty calculated based on the deviation (proportional to the deviation) is output. When the drive duty is output immediately, the operation start shock is output. Occurs, a drive duty line that increases at a constant rate of increase from a minimum drive duty is compared with a drive duty line calculated based on the deviation, and the lower drive duty is selectively output. ing.
[0017]
Next, differences between the “comparison output data set (mode 1)” and the “comparison output data set (mode 2)” will be described. In the "comparison output data set (mode 1)", as described above, counting of all the delay timers 1 to 3 is started when the deviation is out of the dead zone. When the deviation enters each of the delay ranges 1 to 3, the corresponding delay timers 1 to 3 start counting. In other words, the relative delay processing is performed in each of the delay ranges 1 to 3 to cancel the delay processing in each of the delay ranges 1 to 3 based on when the deviation enters each of the delay ranges 1 to 3. As a result, in the mode 2, it is possible to execute the plowing depth automatic control (position control) suitable for the operation in which stability is emphasized.
[0018]
Next, differences between the “comparison output data set (mode 2)” and the “comparison output data set (mode 3)” will be described. In the “comparison output data set (mode 2)”, the same delay release condition as that of the “comparison output data set (mode 1)” is adopted. A delay cancellation condition is added to cancel the current delay range when the delay timer of the delay range closer to the dead zone than the range has elapsed. In other words, in releasing each delay range based on when the deviation enters each delay range, it is possible to prevent the delay time from becoming unnecessarily long. It is possible to execute automatic plowing depth control (position control) suitable for work that emphasizes control accuracy.
[0019]
Next, differences between the “comparison output data set (mode 2)” and the “comparison output data set (mode 4)” will be described. In the “comparison output data set (mode 2)”, similarly to the “comparison output data set (mode 1)”, the lift arm 5 is kept stopped until the delay timer elapses. In (4)), the elevating operation process of the adjacent delay range close to the dead zone is executed until the delay timer elapses. In other words, in order to operate the lift arm 5 at one step slower even during the delay processing, in mode 4, it is possible to execute automatic plowing depth control (position control) suitable for work in which control accuracy is more important than in mode 2. I can do it. In each of the modes 1 to 4 of the “comparison output data set”, the plowing depth automatic control (position control) having different sensitivities (balance between control accuracy and stability) is executed. By adjusting the dead band width, the number of delay ranges, the delay range width, the delay timer time, the delay range output duty, and the like in 4, the sensitivity can be adjusted very finely in accordance with the working machine, work conditions, and the like. ing.
[0020]
In the apparatus configured as described above, the lift arm 5 that raises and lowers the work implement 3 automatically moves the lift arm 5 based on the deviation between the target cultivation depth value and the sensor value of cultivation depth (the deviation between the target position value and the position sensor value). If the deviation of the operation stop state is out of the dead zone, but is within the delay range, the elevation operation is limited until the predetermined timer time elapses. In this case, when the timer time has elapsed, the lift arm 5 is operated toward the dead zone, so that the state deviating from the dead zone can be tolerated for a long time. As a result, the control accuracy can be improved.
[0021]
Further, since the plurality of delay ranges 1 to 3 are set in multiple stages, and the delay timer time is set longer for the delay range closer to the dead zone, when the deviation is small, the delay is long and the frequent cylinder operation can be prevented. On the other hand, when the deviation is large, it is possible to secure a good control accuracy with a short delay.
[0022]
Further, in mode 1, when the deviation of the operation stop state deviates from the dead zone, the counting of all the delay timers 1 to 3 is started, so that an absolute delay processing centering on the dead zone can be performed. However, when it is not possible to perform stable control by allowing a small fluctuation of the deviation, and when the deviation largely fluctuates, it is possible to quickly cancel the delay processing and secure a good control accuracy.
[0023]
In modes 2 to 4, when the deviation of the operation stop state enters each of the delay ranges 1 to 3, the corresponding delay timers 1 to 3 start counting. Processing can be performed, and as a result, control can be performed with an emphasis on stability while allowing deviation fluctuation as much as possible.
[0024]
In the mode 3, since the current delay range is canceled when the delay timers 1 and 2 of the delay ranges 1 and 2 which are closer to the dead zone than the current delay ranges 2 and 3, the deviation is reduced to each of the delay ranges 1 to 3. While the delay processing of each of the delay ranges 1 to 3 is canceled based on the time when the control enters, the control accuracy can be improved by preventing the delay time from becoming unnecessarily long.
[0025]
Further, in the delay range 1 of the modes 1 to 4, since the minimum drive duty is output when the delay timer 1 has elapsed, the so-called hunting phenomenon can be prevented by operating the lift arm 5 slowly.
[0026]
Further, in the delay ranges 2 and 3 of the modes 1 to 4, when the delay timers 2 and 3 have elapsed, the drive duty is gradually increased to the drive duty according to the deviation, so that the shock at the start of operation is suppressed as much as possible. be able to.
[0027]
Further, in the mode 4, since the raising / lowering operation processing of the adjacent delay ranges 1 and 2 close to the dead zone is executed until the delay timers 1 to 3 of the current delay ranges 1 to 3 elapse, the speed is one step lower even during the delay processing. The lift arm 5 can be operated, and as a result, control stability can be improved while ensuring stability.
[0028]
Further, since each delay range width and each delay time can be switched according to the type of the work machine 3, even if the degree of deviation of the deviation differs for each work machine 3, an appropriate delay range width and delay If the time is set, control having both good stability and control accuracy can be performed regardless of the type of the work machine 3.
[0029]
In addition, when the tillage depth setting volume 15 is operated, all the delay ranges 1 to 3 are released, so that the responsiveness, operability and setting accuracy at the time of the tillage depth setting operation can be improved.
[0030]
Note that the present invention is not limited to the above-described embodiment, and for example, a delay range (a passed delay range) closer to the dead zone than the current delay range may be canceled. In this case, when the deviation attempts to return to the delay range on the dead zone side, the lift arm can be operated immediately, thereby preventing the delay time from becoming unnecessarily long and improving control accuracy. Can be.
[Brief description of the drawings]
FIG. 1 is a side view of a tractor.
FIG. 2 is a block diagram showing input and output of a control unit.
FIG. 3 is a flowchart showing a main routine.
FIG. 4 is a flowchart illustrating “tilling depth setting volume check”.
FIG. 5 is a flowchart showing “comparison output data set (mode 1)”.
FIG. 6 is a timing chart showing the operation of “comparison output data set (mode 1)”.
FIG. 7 is a flowchart showing “comparison output data set (mode 2)”.
FIG. 8 is a timing chart showing the operation of “comparison output data set (mode 2)”.
FIG. 9 is a flowchart showing “comparison output data set (mode 3)”.
FIG. 10 is a timing chart showing the operation of “comparison output data set (mode 3)”.
FIG. 11 is a flowchart showing “comparison output data set (mode 4)”.
FIG. 12 is a timing chart showing an output duty.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Traveling machine body 3 Work machine 5 Lift arm 7 Lift cylinder 8 Electromagnetic switching valve 9 for lift arm 9 Control part 10 Lift arm sensor 11 Plow depth sensor 13 Position sensor 15 Plow depth setting volume

Claims (3)

A lift arm that raises and lowers the work machine; and an automatic control unit that automatically controls the lift arm. The automatic control unit further includes a deviation calculation unit that calculates a deviation between a target position and a detected position, and a deviation zone setting unit that sets the deviation to a dead zone. In the tractor provided with an operation command output means for outputting a lift arm operation command when the value exceeds the value, the deviation of the operation stop state exceeds the dead zone set value and is within the delay processing range set value in the automatic control unit. When providing delay processing means for limiting the output of the lift arm operation command until a predetermined timer time elapses , a plurality of delay processing ranges are set in a multi-stage manner, and the delay processing time is set closer to the delay processing range closer to the dead zone. A tractor characterized in that when the deviation of the operation stop state exceeds a dead zone set value, the count of the total delay timer is started . A lift arm that raises and lowers the work machine; and an automatic control unit that automatically controls the lift arm. The automatic control unit further includes a deviation calculation unit that calculates a deviation between a target position and a detected position, and a deviation zone setting unit that sets the deviation to a dead zone. In the tractor provided with an operation command output means for outputting a lift arm operation command when the value exceeds the value, the deviation of the operation stop state exceeds the dead zone set value and is within the delay processing range set value in the automatic control unit. When providing delay processing means for limiting the output of the lift arm operation command until a predetermined timer time elapses, a plurality of delay processing ranges are set in a multi-stage manner, and the delay processing time is set closer to the delay processing range closer to the dead zone. When the deviation of the operation stop state enters each delay processing range, the corresponding delay timer starts counting, and When the delay timer time of the delay processing range close to the dead zone has passed, tractor and cancels the delay processing range at least the current position. A lift arm that raises and lowers the work machine; and an automatic control unit that automatically controls the lift arm. The automatic control unit further includes a deviation calculation unit that calculates a deviation between a target position and a detected position, and a deviation zone setting unit that sets the deviation to a dead zone. In the tractor provided with an operation command output means for outputting a lift arm operation command when the value exceeds the value, the deviation of the operation stop state exceeds the dead zone set value and is within the delay processing range set value in the automatic control unit. When providing delay processing means for limiting the output of the lift arm operation command until a predetermined timer time elapses, a plurality of delay processing ranges are set in a multi-stage manner, and the delay processing time is set closer to the delay processing range closer to the dead zone. A tractor characterized by releasing a delay processing range that is longer and closer to a dead zone than a delay processing range currently located .

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