Patent Application
20210025127
This application claims priority to Japanese Patent Application No. 2019-134678 filed on Jul. 22, 2019, the disclosure of which is hereby incorporated herein by reference in its entirety.
The present invention relates to a system and a method for controlling a bulldozer.
Conventionally, a bulldozer includes an operating member for automatically adjusting the angle of a blade. For example, the bulldozer in Japanese Patent No. 5143975 includes a blade operating lever and an auto-pitch button. The operator is able to manually adjust the angle of the blade by operating the blade operating lever. In addition, when the operator presses the auto-pitch button, the angle of the blade is automatically adjusted to become a predetermined target angle.
In the abovementioned bulldozer, the operator needs to operate different operating members when manually adjusting the angle of the blade and automatically adjusting the angle of the blade. As a result, the operations for adjusting the angle of the blade are complicated.
An object of the present disclosure is to improve operability for adjusting the angle of the blade in a bulldozer.
A system according to a first aspect is a system for controlling a bulldozer including a blade. The system includes an operating device and a controller. The operating device outputs a signal corresponding to an operation by an operator. The controller receives the signal from the operating device. The controller determines that the signal from the operating device represents either a normal operation for manually controlling the blade or a trigger operation for automatically controlling the blade. The controller moves the blade so that the angle of the blade is changed in accordance with the operation of the operating device when the signal from the operating device is determined as representing the normal operation. The controller moves the blade until the angle of the blade reaches a predetermined target angle when the signal from the operating device is determined as representing the trigger operation during the travel of the bulldozer.
A system according to a second aspect is a method for controlling a bulldozer including a blade. The method includes the following processes. A first process involves receiving a signal in accordance with an operation of an operating device by an operator. The second process involves determining that the signal represents either a normal operation for manually controlling the blade or a trigger operation for automatically controlling the blade. The third process involves moving the blade so that the angle of the blade is changed in accordance with the operation of the operating device when the signal is determined as representing a normal operation. The fourth process involves moving the blade until the angle of the blade reaches a predetermined target angle when the signal is determined as representing the trigger operation while the bulldozer is traveling.
Hereinbelow, embodiments of the present invention will be described with reference to the drawings.
The vehicle body 2 has an operating cabin 11 and an engine compartment 12. The engine compartment 12 is disposed in front of the operating cabin 11. The travel device 3 is attached to the vehicle body 2. The travel device 3 includes left and right crawler belts 13. Only the crawler belt 13 on the left side is illustrated in
The first work implement 4 is attached to the vehicle body 2.
The lift frame 14 supports the blade 15. The blade 15 is disposed in front of the vehicle body 2. The blade 15 is attached to the lift frame 14 in a manner that allows movement around a first rotating axis Ax1. The first rotating axis Axl extends in the vehicle width direction.
The lift frame 14 is attached to the travel device 3 in a manner that allows movement around a second rotating axis Ax2. The second rotating axis As extends in the vehicle width direction. The lift frame 14 may be attached to the vehicle body 2. The lift frame 14 includes a left frame 14a and a right frame 14b. The blade 15 moves up and down accompanying the up and down movements of the lift frame 14.
The lift cylinders 16a and 16b are connected to the blade 15 and the vehicle body 2. The lift cylinders 16a and 16b include a left lift cylinder 16a and a right lift cylinder 16b. Due to the extension and contraction of the lift cylinders 16a and 16b, the lift frame 14 moves around the second rotating axis Ax1. Consequently, the blade 15 moves up and down.
The tilt cylinders 17a and 17b are connected to the lift frame 14 and the blade 15. The tilt cylinders 17a and 17b include a left tilt cylinder 17a and a right tilt cylinder 17b. The left tilt cylinder 17a is connected to the left lift frame 14a and the blade 15. The right tilt cylinder 17b is connected to the right frame 14b and the blade 15.
The left tilt cylinder 17a and the right tilt cylinder 17b both extend and contract whereby the blade 15 moves around the first rotating axis Ax1. Consequently, the blade 15 is tilted in the front-back direction. The tilting movement of the blade 15 in the front-back direction is called a pitch movement. Specifically, the left tilt cylinder 17a and the right tilt cylinder 17b both extend whereby the blade 15 tilts forward. The left tilt cylinder 17a and the right tilt cylinder 17b both contract whereby the blade 15 tilts rearward.
By stopping one of the left tilt cylinder 17a and the right tilt cylinder 17b and extending the other thereof, the blade 15 tilts in the left-right direction. The tilting movement of the blade 15 in the left-right direction is called a tilting movement. Specifically, by extending the left tilt cylinder 17a and stopping the right tilt cylinder 17b, the left side of the blade 15 moves upward (hereinbelow, this movement is called left tilt). By extending the right tilt cylinder 17b and stopping the left tilt cylinder 17a, the right side of the blade 15 moves upward (hereinbelow, this movement is called right tilt).
As illustrated in
The power transmission device 24 transmits driving power of the engine 21 to the travel device 3. The power transmission device 24 may be a hydrostatic transmission (HST), for example. Alternatively, the power transmission device 24, for example, may be a transmission having a torque converter or a plurality of speed change gears.
The control system 6 includes a travel operating device 25, a ripper operating device 26, a blade operating device 27, a pitch operating device 32, a controller 28, and a control valve 29. The travel operating device 25, the ripper operating device 26, the blade operating device 27, and the pitch operating device 32 are disposed in the operating cabin 11.
In the present embodiment, the travel operating device 25 is a lever.
The travel of the bulldozer 1 is controlled in accordance with the operation of the travel operating device 25. The travel operating device 25 are operable forward and backward and left and right. The travel operating device 25 outputs an operation signal in accordance with the operating direction of the travel operating device 25. The travel operating device 25 receives the operation by the operator and outputs the operation signal to the controller 28.
In the present embodiment, the ripper operating device 26 is a lever. The movement of the ripper 18 is controlled in accordance with the operation of the ripper operating device 26. The ripper operating device 26 is operable forward and backward or left and right. The ripper operating device 26 outputs an operation signal in accordance with the operating direction of the ripper operating device 26. The ripper operating device 26 receives the operation by the operator and outputs the operation signal to the controller 28.
In the present embodiment, the blade operating device 27 is a lever. The movement of the blade 15 is controlled in accordance with the operation of the blade operating device 27. The blade operating device 27 is operable forward and backward and left and right. The upward, downward, left tilt and right tilt movements of the blade 15 are controlled in accordance with the operation of the blade operating device 27. The blade operating device 27 outputs an operation signal in accordance with the operating direction of the blade operating device 27. The blade operating device 27 receives the operation by the operator and outputs the operation signal to the controller 28.
The travel operating device 25, the ripper operating device 26, and/or the blade operating device 27 may include a plurality of operating members. The travel operating device 25, the ripper operating device 26, and/or the blade operating device 27 are not limited to levers and may be pedals or switches in another embodiment.
Alternatively, the pitch operating device 32 may be operable by sliding. The pitch operating device 32 can be moved from a neutral position in
The pitch operating device 32 outputs an operation signal in accordance with the operating direction of the pitch operating device 32. The pitch operating device 32 receives the operation by the operator and outputs the operation signal to the controller 28. The pitch movement of the blade 15 is controlled in accordance with the operating direction of the pitch operating device 32. Specifically, the pitch operating device 32 is operated in the first direction A1 whereby the blade 15 is tilted forward. The pitch operating device 32 is operated in the second direction A2 whereby the blade 15 is tilted rearward.
The controller 28 is programmed to control the bulldozer 1 based on acquired data. As illustrated in
The processor 35 may be, for example, a central processing unit (CPU). The processor 35 executes processing for controlling the bulldozer 1 in accordance with a program. The controller 28 controls the travel device 3 or the power transmission device 24 thereby causing the bulldozer 1 to travel. The controller 28 controls the control valve 29 whereby the blade 15 is moved up and down.
The control valve 29 a proportional control valve and is controlled by a command signal from the controller 28. The control valve 29 is disposed between hydraulic actuators and the hydraulic pump 23. The hydraulic actuators include the lift cylinders 16a and 16b, the tilt cylinders 17a and 17b, and the ripper cylinders 19 and 20.
The control valve 29 includes lift control valve 291 and 292, tilt control valve 293 and 294, and ripper control valve 295 and 296. The lift control valve 291 and 292 control the flow rate of the hydraulic fluid supplied from the hydraulic pump 23 to the lift cylinders 16a and 16b. The controller 28 generates instruction signals to the lift control valve 291 and 292 in accordance with the operation of the blade operating device 27. As a result, the lift cylinders 16a and 16b are controlled so that the blade 15 moves upward or downward.
The tilt control valve 293 and 294 control the flow rate of the hydraulic fluid supplied from the hydraulic pump 23 to the tilt cylinders 17a and 17b. The controller 28 generates instruction signals to the tilt control valve 293 and 294 in accordance with the operation of the blade operating device 27, As a result, the tilt cylinders 17a and 17b are controlled so that the blade 15 performs left tilting or right tilting. The controller 28 also generates instruction signals to the tilt control valve 293 and 294 in accordance with the operation of the pitch operating device 32. As a result, the tilt cylinders 17a and 17b are controlled so that the blade 15 performs forward tilting or rearward tilting.
The ripper control valve 295 and 296 control the flow rate of the hydraulic fluid supplied from the hydraulic pump 23 to the ripper cylinders 19 and 20. The controller 28 generates instruction signals to the ripper control valve 295 and 296 in accordance with the operation of the ripper operating device 26. As a result, the ripper cylinders 19 and 20 are controlled so that the ripper 18 moves.
The control valve 29 may be a pressure proportional control valve, In this case, a pilot pressure that corresponds to the operation of the blade operating device 27 may be inputted to the control valve 29. Alternatively, the control valve 29 may be an electromagnetic proportional control valve. An electrical signal that corresponds to the operation of the blade operating device 27 may be inputted to the control valve 29.
The automatic control of the blade 15 is explained next. In the bulldozer 1 according to the present embodiment, the controller 28 executes an auto-pitch control for automatically controlling the pitch angle of the blade 15. The pitch angle is the tilting angle of the blade 15 in the front-back direction. The pitch angle is changed by the abovementioned pitch movement of the blade 15.
As illustrated in step S101 in
When the operation signal from the pitch operating device 32 does not represent the trigger operation, the processing advances to step S103. That is, when the operation signal from the pitch operating device 32 represents a normal operation for manual operation of the blade 15, the processing advances to step S103. In step S103, the controller 28 changes the pitch angle according to the manual operation. In the manual control, the controller 28 changes the pitch angle while the pitch operating device 32 is being operated by the operator.
For example, while the pitch operating device 32 is being operated in the first direction Al, the controller 28 keeps the blade 15 moving so that the blade 15 tilts forward. While the pitch operating device 32 is being operated in the second direction A2, the controller 28 keeps the blade 15 moving so that the blade 15 tilts rearward. The controller 28 causes the blade 15 to stand still without performing a pitch movement when the pitch operating device 32 is not operated by the operator. That is, when the pitch operating device 32 is returned to the neutral position after the operation of the pitch operating device 32, the controller 28 stops the pitch movement of the blade 15.
When the controller 28 determines that the operation signal from the pitch operating device 32 represents the trigger operation in step S102, the processing advances to step S104. In step S104, the controller 28 acquires the traveling state of the bulldozer 1. The traveling state includes forward travel, reverse travel, and stopping. The controller 28 acquires the traveling state, for example, based on the operation signal from the travel operating device 25. Alternatively, the controller 28 may acquire the traveling state by detecting the state of the travel device 3 or the power transmission device 24. Alternatively, the controller 28 may acquire the traveling state with a positional sensor such as a global positioning system (GPS).
In step S105, the controller 28 determines whether the bulldozer 1 is traveling. The controller 28 determines whether the bulldozer 1 is traveling based on the traveling state acquired in step S104. The controller 28 does not execute the automatic control when it is determined that the bulldozer 1 is not traveling. That is, the controller 28 disables the trigger operation when it is determined that the bulldozer 1 is stopped.
When the controller 28 determines that the bulldozer 1 is traveling, the process advances to step S106.
In step S106, the controller 28 changes the pitch angle according to the auto-pitch control. In the auto-pitch control, the controller 28 moves the blade 15 until the pitch angle of the blade 15 has reached the target angle even if the pitch operating device 32 has returned to the neutral position.
In step S107, the controller 28 determines whether the pitch angle of the blade 15 has reached the target angle. When the pitch angle of the blade 15 has reached the target angle, in step S108, the controller 28 stops the pitch movement of the blade 15.
The controller 28 changes the first target angle in accordance with the operating direction of the pitch operating device 32. As illustrated in
As illustrated in
When the controller 28 determines that the operation signal from the pitch operating device 32 represents the trigger operation while the bulldozer 1 is traveling in reverse, the controller 28 moves the blade 15 until the angle of the blade 15 reaches a second target angle. The second target angle is different from the first target angle. The second target angle is an angle between the maximum pitch angle in the forward direction and the maximum pitch angle in the rearward direction. The second target angle is an angle that suits excavation. The second target angle is set beforehand and is saved in the storage device 34. The second target angle may be fixed value. Alternatively, the second target angle may be changeable.
As illustrated in
As illustrated in
The controller 28 uses a timer when changing the pitch angle up to the second target angle. After the tilt cylinders 17a and 17b have reached the stroke ends, the controller 28 tilts the blade 15 forward or rearward until a predetermined action time period has been completed. At the point in time that the predetermined action time period has been completed after the tilt cylinders 17a and 17b have reached the stroke ends, the controller 28 stops the forward tilt or rearward tilt of the blade 15.
The controller 28 refers to action time period data illustrated in
The action time period data includes first data El and second data E2. The first data E1 defines the relationship between the engine rotation speed and the action time period when the trigger operation is performed in the first direction Al while the bulldozer 1 is traveling in reverse. The second data E1 defines the relationship between the engine rotation speed and the action time period when the trigger operation is performed in the second direction A2 while the bulldozer 1 is traveling in reverse.
In the control system 6 of the bulldozer 1 according to the present embodiment as explained above, the operator is able to use the pitch operating device 32 to indicate both the manual control and the automatic control of the blade 15. Consequently, operability for adjusting the angle of the blade 15 is improved in the bulldozer 1.
The configuration of the bulldozer 1 is not limited to the above embodiment and may be changed. For example, the bulldozer 1 may be driven by an electric motor. The second work implement 5 may be omitted. The configuration of the control system 6 is not limited to the above embodiment and may be changed. The bulldozer 1 may be remotely operable. In this case, a portion of the control system 6 may be disposed outside of the bulldozer 1.
For example as illustrated in
The travel operating device 25, the ripper operating device 26, the blade operating device 27, and/or the pitch operating device 32 may be disposed outside of the bulldozer 1. The travel operating device 25, the ripper operating device 26, the blade operating device 27, and/or the pitch operating device 32 may be omitted from the bulldozer 1. In this case, the operating cabin 11 may be omitted from the work vehicle 1.
The remote controller 281 and the on-board controller 282 may be able to communicate wirelessly through communication devices 38 and 39. A portion of the functions of the abovementioned controller 28 may be executed by the remote controller 281 and the remaining functions may be executed by the on-board controller 282.
The structures or the dispositions of the travel operating device 25, the ripper operating device 26, the blade operating device 27, and/or the pitch operating device 32 are not limited to the above embodiment and may be changed. For example, the pitch operating device 32 is not limited to the shape of the above embodiment and may have another shape such as a lever shape.
The processes of the automatic control of the blade 15 are not limited to the above embodiment and may be changed, omitted, or other processes may be added. The sequence of the execution of the processes of the automatic control is not limited to the above embodiment and may be changed.
The trigger operation is not limited to pushing and holding and may be another operation. For example, the trigger operation may be a predetermined number of continuous clicks of the pitch operating device 32. The predetermined number may be two clicks, for example. Alternatively, the predetermined number may be more than two.
The control system 6 may be provided with an angle sensor for detecting the angle of the blade 15. The angle sensor may also detect the pitch angle. The controller 28 may use the pitch angle detected by the angle sensor to change the pitch angle to the second target angle.
When the taveling direction of the bulldozer 1 is changed during the auto-pitch control, the controller 28 may end the auto-pitch control. When the bulldozer 1 stops during the auto-pitch control, the controller 28 may end the auto-pitch control. When the ripper operating device 26 is operated during the auto-pitch control, the controller 28 may end the auto-pitch control. Alternatively, when any of the above operations are performed during the auto-pitch control, the controller 28 may temporarily end the auto-pitch control. When said operation is ended, the auto-pitch control may be restarted.
The automatic control of the blade 15 is performed for the pitch movement in the above embodiment. However, the automatic control is not limited to the pitch movement, and the automatic control of the blade 15 may be performed on another operation such as the lift operation or the tilt operation.
Although an embodiment of the present invention has been described, the present invention is not limited to the above embodiment and various modifications may be made within the scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-134678 | Jul 2019 | JP | national |
