JP2023150704A - Work machine and control method of work machine - Google Patents

Abstract

To provide a work machine capable of automatically and accurately bucketing a specified amount of soil.SOLUTION: A work machine comprises a travelable vehicle body, a work tool carrying out excavation work with a bucket; and a controller. The controller has first calculation means for acquiring mechanical data on motion of the vehicle body and the working tool to calculate a target attitude of the work tool during the excavation work based on the mechanical data, and second calculation means for calculating an accelerator opening necessary to excavate a target excavation amount of soil. The controller controls motion of the work tool so as to make the attitude of the work tool be the target attitude and travel of the vehicle body based on the accelerator opening.SELECTED DRAWING: Figure 7

Description

The present disclosure relates to a work machine and a method of controlling the work machine.

Conventionally, in order for an operator of a working machine to excavate a desired amount of soil with a working machine, the operator's experience and skill are required. For this reason, in recent years, work machines that control the posture of the work machine using learned models have been developed.

For example, Japanese Patent Application Laid-Open No. 2021-143555 (Patent Document 1) describes a target value of the amount of work performed by the work machine, an elapsed time from the start of work by the work machine, and the time when the work machine is installed. The wheel loader is equipped with a computer that acquires machine data regarding the motion of the vehicle body and work equipment, and outputs an estimated target posture by estimating the target posture from the target value, elapsed time, and machine data using a learned posture estimation model. Disclosed.

Furthermore, in recent years, an HMT (Hydraulic Mechanical Transmission) wheel loader that utilizes electronic control has been developed (Non-Patent Document 1). The HMT wheel loader that utilizes electronic control has both the high work efficiency of a wheel loader equipped with a torque converter and a mechanical transmission, and the high operability of a wheel loader using an HST (Hydrostatic transmission) system. has been realized.

JP 2021-143555 Publication

Takuya Muramoto and two others “Development of HMT (Hydraulic Mechanical Transmission) wheel loader using electronic control”, [online], 2020 Construction and Construction Machinery Symposium Collected Papers and Abstracts, [2020 2 Searched on the 7th of the month], <URL: https://jcmanet.or.jp/bunken/symposium/2020/ronbun15.pdf>

There is a need for working machines to automatically scoop a specified amount of soil more accurately than before. An object of the present disclosure is to provide a working machine and a method of controlling the working machine that can automatically and accurately scoop a designated amount of soil.

According to an aspect of the present disclosure, a working machine includes a movable vehicle body, a working machine that includes a bucket and performs excavation work with the bucket, and a controller. The controller acquires machine data regarding the operation of the vehicle body and the work equipment, and includes a first calculation means that calculates a target posture of the work equipment during excavation work based on the machine data, and a first calculation means that calculates a target posture of the work equipment during excavation work based on the machine data. and second calculation means for calculating the accelerator opening degree. The controller controls the operation of the work machine so that the attitude of the work machine becomes a target attitude, and also controls the traveling of the vehicle body based on the accelerator opening degree.

According to another aspect of the present disclosure, a method for controlling a working machine including a travelable vehicle body and a working machine having a bucket acquires machine data regarding the operation of the vehicle body and the working machine, and performs excavation based on the machine data. A step of calculating the target posture of the work equipment during work, a step of calculating the accelerator opening degree required to excavate the target amount of soil to be excavated, and a step of controlling the operation of the work equipment so that the attitude of the work equipment matches the target attitude. and a step of controlling the running of the vehicle body based on the accelerator opening degree.

According to the present disclosure, it becomes possible to automatically and accurately scoop a designated amount of soil.

FIG. 1 is a side view of a wheel loader as an example of a working machine based on an embodiment. FIG. 1 is a schematic block diagram showing the configuration of a wheel loader according to an embodiment. FIG. 2 is a diagram for explaining the concept of independent control of a working machine and traveling. It is a figure explaining excavation work by a wheel loader. FIG. 2 is a flow diagram for explaining an overview of the flow of processing executed by the wheel loader. It is a flowchart for explaining the modification of the flow of processing performed by a wheel loader. FIG. 3 is a diagram for explaining calculations executed by a controller. FIG. 3 is a diagram schematically illustrating processing executed by a calculation unit. It is a figure for explaining the excavation work when the calculated accelerator opening is large. 10 is a diagram for explaining excavation work when the calculated accelerator opening degree is smaller than the accelerator opening degree shown in FIG. 9. FIG. FIG. 3 is a diagram for explaining excavation accuracy by automatic control of work machine operation and accelerator operation. Assuming that the total amount of soil loaded onto the dump truck is 18 tons, the amount of soil loaded onto the dump truck for 10 times when excavating with automatic control of work equipment operation and accelerator operation, and when excavating with manual operation. It is a diagram showing the amount of soil and loading accuracy. 13 is a diagram showing the average value, cycle time, and fuel consumption of the data shown in FIG. 12. FIG. FIG. 6 is a diagram for further explaining fuel efficiency by automatic control of work equipment operation and accelerator operation. FIG. 2 is a functional block diagram for explaining the functional configuration of a calculation unit. FIG. 3 is a flow diagram for explaining the flow of generating a correction formula. FIG. 3 is a diagram for explaining the relationship between the target excavated soil volume used when generating a correction formula and the measured value by a payload meter. FIG. 3 is a flowchart for explaining a series of processing steps from inputting the total amount of earth and sand to be loaded onto a dump truck to correction by a correction section.

Hereinafter, embodiments will be described based on the drawings. In the following description, the same parts are given the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated.

<A. Overall configuration>
In the embodiment, a wheel loader 1, which is a type of self-propelled working machine, will be described as an example of a working machine. FIG. 1 is a side view of a wheel loader 1 as an example of a working machine based on an embodiment.

As shown in FIG. 1, the wheel loader 1 includes a vehicle body frame 2, a working machine 3, a traveling device 4, and a cab 5. A vehicle body 20 of the wheel loader 1 is composed of a vehicle body frame 2, a cab 5, and the like. A working machine 3 and a traveling device 4 are attached to the vehicle body 20.

The traveling device 4 causes the vehicle body 20 to travel, and includes running wheels 4a and 4b. The wheel loader 1 is self-propelled by rotationally driving running wheels 4a and 4b, and can perform desired work using the working machine 3.

The vehicle body frame 2 includes a front frame 2a and a rear frame 2b. The front frame 2a and the rear frame 2b are attached to each other so as to be swingable in the left-right direction. A pair of steering cylinders 11 are attached across the front frame 2a and the rear frame 2b. Steering cylinder 11 is a hydraulic cylinder. As the steering cylinder 11 expands and contracts with hydraulic oil from a steering pump (not shown), the traveling direction of the wheel loader 1 is changed to the left or right.

In this specification, the direction in which the wheel loader 1 travels straight is referred to as the front-rear direction of the wheel loader 1. In the front-rear direction of the wheel loader 1, the side on which the working machine 3 is arranged with respect to the vehicle body frame 2 is defined as the front direction, and the side opposite to the front direction is defined as the rear direction. The left-right direction of the wheel loader 1 is a direction perpendicular to the front-rear direction in plan view. Looking forward, the right and left sides in the left and right direction are the right direction and left direction, respectively. The vertical direction of the wheel loader 1 is a direction perpendicular to a plane defined by the front-rear direction and the left-right direction. In the vertical direction, the side with the ground is the bottom, and the side with the sky is the top.

A working machine 3 and a pair of running wheels (front wheels) 4a are attached to the front frame 2a. The work machine 3 is arranged in front of the vehicle body 20. The work machine 3 is driven by hydraulic oil from a work machine pump 13 (see FIG. 2). The work machine pump 13 is a hydraulic pump that is driven by the engine 21 and operates the work machine 3 with the hydraulic fluid it discharges. The work machine 3 includes a boom 14 and a bucket 6 that is a work tool. The bucket 6 is arranged at the tip of the working machine 3. The bucket 6 is an example of an attachment that is detachably attached to the tip of the boom 14. Depending on the type of work, attachments can be changed to grapples, forks, or plows.

A base end portion of the boom 14 is rotatably attached to the front frame 2a by a boom pin 9. The bucket 6 is rotatably attached to the boom 14 by a bucket pin 17 located at the tip of the boom 14.

The front frame 2a and the boom 14 are connected by a pair of boom cylinders 16. Boom cylinder 16 is a hydraulic cylinder. A base end of the boom cylinder 16 is attached to the front frame 2a. The tip of the boom cylinder 16 is attached to the boom 14. The boom 14 moves up and down as the boom cylinder 16 expands and contracts with the hydraulic oil from the work equipment pump 13 (see FIG. 2). The boom cylinder 16 rotates the boom 14 up and down about the boom pin 9.

The work machine 3 further includes a bell crank 18, a bucket cylinder 19, and a link 15. The bell crank 18 is rotatably supported by the boom 14 by a support pin 18a located approximately at the center of the boom 14. The bucket cylinder 19 connects the bell crank 18 and the front frame 2a. The link 15 is connected to a connecting pin 18c provided at the tip of the bell crank 18. Link 15 connects bell crank 18 and bucket 6.

The bucket cylinder 19 is a hydraulic cylinder and a working tool cylinder. The base end of the bucket cylinder 19 is attached to the front frame 2a. The tip of the bucket cylinder 19 is attached to a connecting pin 18b provided at the base end of the bell crank 18. The bucket 6 rotates up and down as the bucket cylinder 19 expands and contracts with the hydraulic oil from the working machine pump 13 (see FIG. 2). The bucket cylinder 19 rotates the bucket 6 around the bucket pin 17 .

A cab 5 and a pair of running wheels (rear wheels) 4b are attached to the rear frame 2b. The cab 5 is arranged behind the boom 14. The cab 5 is placed on the vehicle body frame 2. Inside the cab 5, a seat on which an operator of the wheel loader 1 sits, an operating device 8, which will be described later, and the like are arranged.

<B. System configuration>
FIG. 2 is a schematic block diagram showing the configuration of the wheel loader 1 based on the embodiment. As shown in FIG. 2, the wheel loader 1 includes an engine 21 as a driving source, a traveling device 4, a working machine pump 13, an operating device 8, a controller 10, a display 50, and the like.

Engine 21 is, for example, a diesel engine. The output of the engine 21 is controlled by adjusting the amount of fuel injected into the cylinder. This adjustment is performed by controlling an electronic governor (not shown) by the controller 10.

The engine rotation speed is detected by an engine rotation speed sensor 91. A detection signal from the engine rotation speed sensor 91 is input to the controller 10 .

The traveling device 4 is a device that causes the wheel loader 1 to travel using driving force from the engine 21. The traveling device 4 includes a transmission 23, the aforementioned front wheels 4a and rear wheels 4b, and the like.

The transmission 23, which is a power transmission device, is a device that transmits the driving force from the engine 21 to the front wheels 4a and the rear wheels 4b. In the wheel loader 1, both the front wheel 4a attached to the front frame 2a and the rear wheel 4b attached to the rear frame 2b constitute driving wheels that receive driving force and cause the wheel loader 1 to travel. . The transmission 23 changes the speed of the rotation of the input shaft 27 and outputs the same to the output shaft 28 .

An output rotation speed sensor 92 is provided on the output shaft 28 . The output rotation speed sensor 92 detects the rotation speed of the output shaft 28 . A detection signal from the output rotation speed sensor 92 is input to the controller 10. The controller 10 calculates the vehicle speed based on the detection signal of the output rotation speed sensor 92.

The driving force output from the transmission 23 is transmitted to the wheels 4a and 4b via the axle 32 and the like. Thereby, the wheel loader 1 travels. A portion of the driving force from the engine 21 is transmitted to the traveling device 4, and the wheel loader 1 travels.

A part of the driving force of the engine 21 is transmitted to the work equipment pump 13 via the power extraction section 33.

The work equipment pump 13 and the steering pump are hydraulic pumps driven by the driving force from the engine 21. Hydraulic oil discharged from the work equipment pump 13 is supplied to the boom cylinder 16 and the bucket cylinder 19 via the work equipment valve 34. The work machine 3 is driven by a portion of the driving force from the engine 21.

The first oil pressure detector 95 is attached to the boom cylinder 16. The first oil pressure detector 95 detects the pressure of hydraulic oil in the oil chamber of the boom cylinder 16 . A detection signal from the first oil pressure detector 95 is input to the controller 10.

The second oil pressure detector 96 is attached to the bucket cylinder 19. The second oil pressure detector 96 detects the pressure of the hydraulic oil in the oil chamber of the bucket cylinder 19 . A detection signal from the second oil pressure detector 96 is input to the controller 10.

The first angle detector 29 is, for example, a potentiometer attached to the boom pin 9. The first angle detector 29 detects a boom angle that represents the lifting angle of the boom 14 with respect to the vehicle body 20. The first angle detector 29 outputs a detection signal indicating the boom angle to the controller 10.

Specifically, as shown in FIG. 1, the boom reference line P is a straight line passing through the center of the boom pin 9 and the center of the bucket pin 17. The horizontal line H is parallel to the front-rear direction of the wheel loader 1. Horizontal line H extends forward from the center of boom pin 9. The boom angle θ1 is the angle between the horizontal line H extending forward from the center of the boom pin 9 and the boom reference line P. When the boom reference line P is horizontal, the boom angle θ1 is defined as 0°. When the boom reference line P is above the horizontal line H, the boom angle θ1 is positive. When the boom reference line P is below the horizontal line H, the boom angle θ1 is set to be negative.

Note that the first angle detector 29 may be a stroke sensor disposed on the boom cylinder 16.

The second angle detector 48 is, for example, a potentiometer attached to the support pin 18a. The second angle detector 48 detects a bellcrank angle that represents the angle of the bellcrank 18 with respect to the boom 14 . The second angle detector 48 outputs a detection signal indicating the bellcrank angle to the controller 10.

Specifically, as shown in FIG. 1, the bellcrank reference line Q is a straight line passing through the center of the support pin 18a and the center of the connection pin 18b. The bell crank angle θ2 is the angle formed by the boom reference line P and the bell crank reference line Q. The center of the support pin 18b (hereinafter also referred to as "Ua"), the intersection of the boom reference line P and the bell crank reference line Q (hereinafter also referred to as "Ub"), and the center of the boom pin 9 (hereinafter referred to as "Uc") In a triangle UaUbUc (not shown) whose apex is UaUbUc (also referred to as UaUbUc), the bellcrank angle θ2 is ∠UaUbUc.

The second angle detector 48 may detect the angle of the bucket 6 with respect to the boom 14 (bucket angle θ3). The bucket angle θ3 is an angle formed by a straight line R passing through the center of the bucket pin 17 and the cutting edge 6a of the bucket 6 and the boom reference line P. The position of the cutting edge 6a of the bucket 6 (hereinafter also referred to as "Ud"), the intersection of the boom reference line P and the straight line R ("Uf"), and the position of the boom pin 9 located on the reference line P and with respect to the above-mentioned intersection. In a triangle UdUfUe (not shown) whose apex is a point located on the opposite side of the center (Uc) (hereinafter also referred to as "Ue"), the bucket angle θ3 is ∠UdUfUe.

The second angle detector 48 may be a potentiometer or a proximity switch attached to the bucket pin 17. Alternatively, the second angle detector 48 may be a stroke sensor disposed on the bucket cylinder 19.

The operating device 8 is operated by an operator. The operating device 8 includes a plurality of types of operating members that are operated by an operator to operate the wheel loader 1. Specifically, the operating device 8 includes an accelerator operating member 81a, a boom operating member 83a, and a bucket operating member 84a.

The accelerator operating member 81a is, for example, an accelerator pedal. When the amount of operation of the accelerator operation member 81a (the amount of depression in the case of an accelerator pedal) is increased, the vehicle body 20 accelerates. When the amount of operation of the accelerator operation member 81a is decreased, the vehicle body 20 is decelerated. The accelerator operation detection unit 81b detects the amount of operation of the accelerator operation member 81a. The operation amount of the accelerator operation member 81a is also referred to as "accelerator opening degree" or "accelerator operation amount." The accelerator operation detection unit 81b detects the accelerator opening degree (hereinafter also referred to as "accelerator opening degree V1"). The accelerator operation detection section 81b outputs a detection signal to the controller 10. The controller 10 controls the output of the engine 21 and the reduction ratio of the transmission 23 based on the detection signal from the accelerator operation detection section 81b.

The accelerator operation detection unit 81b is, for example, a sensor that reads a voltage value (operation signal) based on an accelerator operation. The accelerator operation detection unit 81b may be a device installed in the wheel loader 1 in advance. Alternatively, the accelerator operation detection section 81b may be a device retrofitted to the vehicle body 20. The accelerator operation detection unit 81b is also referred to as an "accelerator opening sensor."

The boom operating member 83a is operated to operate the boom 14. The boom operation member 83a is, for example, an operation lever. The boom operation detection section 83b detects the position of the boom operation member 83a. The boom operation detection section 83b outputs a detection signal to the controller 10. The controller 10 controls the work equipment valve 34 based on the detection signal from the boom operation detection section 83b. The boom cylinder 16 expands and contracts, and the boom 14 operates.

The boom operation detection unit 83b is, for example, a sensor that reads a voltage value (operation signal) based on a lever operation. The boom operation detection unit 83b may be a device installed in the wheel loader 1 in advance. Alternatively, the boom operation detection section 83b may be a device retrofitted to the vehicle body 20.

The bucket operating member 84a is operated to operate the bucket 6. The bucket operating member 84a is, for example, an operating lever. The bucket operation detection section 84b detects the position of the bucket operation member 84a. The bucket operation detection section 84b outputs a detection signal to the controller 10. The controller 10 controls the work machine valve 34 based on the detection signal from the bucket operation detection section 84b. The bucket cylinder 19 expands and contracts, and the bucket 6 operates.

The bucket operation detection unit 84b is, for example, a sensor that reads a voltage value (operation signal) based on a lever operation. The bucket operation detection unit 84b may be a device installed in the wheel loader 1 in advance. Alternatively, the bucket operation detection unit 84b may be a device retrofitted to the vehicle body 20.

The display 50 receives command signals from the controller 10 and displays various information. The various information displayed on the display 50 includes, for example, information regarding the work performed by the wheel loader 1, vehicle body information such as remaining fuel level, cooling water temperature, and hydraulic oil temperature, peripheral images captured around the wheel loader 1, It may also be a value measured by the payload meter 99 (FIG. 15).

The operation key 51 is an input device. The operation key 51 is a device for an operator to input various information into the controller 10. The operation keys may be configured as software keys. Specifically, the wheel loader 1 may include a touch screen in which a touch panel is superimposed on the display 50 as an input device. In this case, a signal generated by the operator touching a portion of the display 50 is output from the touch screen to the controller 10. The operation key 51 does not need to be mounted inside the vehicle. The operation key 51 may be an external terminal.

The controller 10 includes a calculation section 150 and a calculation section 280. The calculation unit 150 acquires mechanical data regarding the operations of the vehicle body 20 and the working machine 3, and calculates a target posture of the working machine 3 during excavation work based on the mechanical data. The mechanical data includes the pressure of the boom cylinder 16, the vehicle speed of the wheel loader 1, the rotational speed of the engine 21, and the tractive force of the wheel loader 1. The calculation unit 150 includes an acquisition unit 170 and a learned model 180. The acquisition unit 170 acquires mechanical data regarding the operation of the vehicle body 20 and the working machine 3. The trained model 180 receives the machine data acquired by the acquisition unit 170 as input. The functions of the trained model 180 and the calculation unit 280 will be described later.

The controller 10 is generally realized by reading various programs using a CPU (Central Processing Unit). The controller 10 has a memory 10M. The memory 10M functions as a work memory and stores various programs for realizing the functions of the wheel loader. The memory 10M stores at least the bucket capacity of the bucket 6 attached to the wheel loader 1 and the learned model 180.

The controller 10 recognizes operator operations such as the accelerator operating member 81a, the boom operating member 83a, and the bucket operating member 84a, and vehicle conditions such as the load on the work equipment 3 and vehicle speed, and controls the hydraulic motors 232 and 233 in the transmission 23. The engine 21 is electronically controlled. Based on the amount of fuel supplied to the engine 21, the controller 10 calculates the amount of fuel consumed per unit operating time of the engine 21, the amount of fuel consumed per unit traveling distance of the wheel loader 1, and the amount of fuel consumed per unit loaded weight in the bucket 6. It is possible to calculate the fuel consumption of

The controller 10 calculates the vehicle speed of the wheel loader 1 based on the detection signal of the output rotation speed sensor 92. The controller 10 reads a map defining the relationship between the vehicle speed and the traction force of the wheel loader 1 from the memory 10M, and calculates the traction force based on the map. The controller 10 receives an engine rotational speed detection signal from the engine rotational speed sensor 91 . The controller 10 reads a map defining the relationship between engine speed and engine torque from memory, and calculates engine torque based on the map.

Traction force and engine torque may be calculated in a different manner than with reference to a map. For example, the traction force and engine torque may be calculated by referring to a table or calculating by a function. Controller 10 automatically controls the operations of boom 14 and bucket 6. Details of this automatic control will be described later.

Next, the transmission 23 will be explained in more detail. In this example, the transmission 23 is an HMT (Hydraulic Mechanical Transmission) that utilizes electronic control. The transmission 23 includes a planetary gear 231 and hydraulic motors 232 and 233.

The transmission 23 performs continuously variable speed by a combination of a planetary gear 231 and two hydraulic motors 232 and 233. Planetary gear 231 includes a ring gear, a carrier, a sun gear, and a planetary gear. Power is transmitted to the outside from the ring gear, carrier, and sun gear. In the transmission 23, the engine 21 is connected to the carrier, the hydraulic motor 233 is connected to the ring gear, and the hydraulic motor 232 and the axle 32 are connected to the sun gear. The planetary gear 231 and each part 21, 32, 232, 233 are connected at reduced speed.

The transmission 23 calculates the target engine speed required for driving and the vehicle speed request by operator operation, and creates a reduction ratio for the transmission by electronically controlling the two hydraulic motors 232 and 233.

The transmission 23 takes advantage of its continuously variable speed feature and separates the rotational speed control of the engine 21 from the operation of the accelerator operation member 81a. As a result, the speed of the work equipment 3 can be controlled only by the work equipment lever (boom operating member 83a, bucket operating member 84a), and the vehicle speed can be controlled only by the accelerator operating member 81a (independent control of the work equipment and traveling). There is.

FIG. 3 is a diagram for explaining the concept of independent control of the work machine and travel. As shown in FIG. 3, the controller 10 acquires information on the work equipment levers (boom operating member 83a, bucket operating member 84a) and accelerator operating member 81a. In the independent control of the work machine 3 and travel, these pieces of information are recognized as a work machine speed request and a vehicle speed request, respectively (processes (i) and (ii)).

When the operator operates the work equipment lever in order to quickly move the work equipment 3, the controller 10 calculates the pump flow rate to produce the required work equipment speed, and sets the target based on the size of the installed work equipment pump 13. Calculate the engine rotation speed (process (iii)). The engine 21 is controlled by the controller 10 based on the target rotation speed, regardless of the operation of the accelerator pedal. That is, the engine speed is automatically controlled by operating the work equipment lever.

On the other hand, the controller 10 calculates the reduction ratio required for the transmission 23 in order to realize the vehicle speed request recognized by the accelerator operating member 81a. The reduction ratio is obtained by calculating the ratio of the engine speed determined by operating the work implement lever to the vehicle speed request determined by accelerator pedal operation. The transmission 23 electronically controls the two hydraulic motors 232 and 233 to achieve a target reduction ratio, thereby enabling the vehicle to travel at the vehicle speed requested by the operator.

In such a wheel loader 1, the work machine speed and the vehicle speed can be independently controlled by independent control of the work machine and traveling, and simple and intuitive operability can be realized. Note that since the configuration of an HMT that utilizes electronic control is already known, it will not be described in further detail here.

<C. Excavation work＞
The wheel loader 1 performs excavation work to scoop up excavated objects such as earth and sand. FIG. 4 is a diagram illustrating excavation work by the wheel loader 1 based on the embodiment.

As shown in FIG. 4, the wheel loader 1 causes the cutting edge 6a of the bucket 6 to bite into the excavated object 100, and then raises the bucket 6 along the bucket trajectory L, as indicated by the curved arrow in FIG. . As a result, the excavation work of scooping up the excavated object 100 into the bucket 6 is executed.

The wheel loader 1 performs an excavation operation in which an excavated object 100 is scooped into a bucket 6, and a loading operation in which the load (excavated object 100) in the bucket 6 is loaded onto a loading object (transportation machine) such as a dump truck. do.

More specifically, the wheel loader 1 excavates the excavated object 100 and loads the excavated object 100 into a loading object by repeating sequentially performing the following plurality of work steps. In the following description, a dump truck will be used as an example of a loading target.

The first step is an empty load advancing step in which the excavation target 100 is moved forward. The second process is an excavation process (plunging) in which the cutting edge 6a of the bucket 6 bites into the excavated object 100 and the wheel loader 1 is advanced until a predetermined amount of the excavated object 100 enters the bucket 6. The third step is an excavation step (scooping) in which the boom cylinder 16 is operated to raise the bucket 6 and the bucket cylinder 19 is operated to tilt the bucket 6 back. The fourth process is a loading backward movement process in which the wheel loader 1 is moved backward after the excavated object 100 is scooped into the bucket 6.

The fifth step is a load advancement step in which the wheel loader 1 is moved forward to approach the dump truck while the bucket 6 is maintained in a raised state or while the bucket 6 is raised. The sixth step is an earth removal step in which the bucket 6 is dumped at a predetermined position and the excavated object 100 is loaded onto the dump truck bed. The seventh step is a backward movement/boom lowering process in which the wheel loader 1 is moved backward while the boom 14 is lowered and the bucket 6 is returned to the digging position. The above is a typical work process that constitutes one cycle of excavation and loading work.

For example, whether the current work process of the wheel loader 1 is an excavation process and the work machine 3 is in the process of excavation, or whether the current work process is not an excavation process and the work machine is not in the process of excavation, can be determined by, for example, The determination can be made by using a combination of an operation signal based on the operator's operation to advance the work implement 3, an operation signal based on the operator's operation on the work implement 3, and a determination condition regarding the current oil pressure of the cylinder of the work implement 3.

<D. Control by controller>
(d1: control structure)
FIG. 5 is a flow diagram for explaining an overview of the flow of processing executed by the wheel loader 1. As shown in FIG. As shown in FIG. 5, in step S1, the controller 10 starts the engine 21 based on an operator's operation. In step S2, the controller 10 receives an operator's operation of the working machine 3 and an operator's operation of the accelerator operating member 81a. The controller 10 performs manual control based on operator operations regarding work machine operation and travel.

In step S3, the controller 10 determines whether an input of the total amount of earth and sand to be loaded onto the dump truck has been received. The input is performed via the operation keys 51, which are input devices. If it is determined that the input of the total amount of earth and sand has been received (YES in step S3), the controller 10 calculates the target excavated earth amount in step S4. The controller 10 calculates the amount of soil per excavation as the target amount of excavated soil.

For example, when the total amount of earth and sand input is 30 tons and the bucket capacity (maximum capacity) of the bucket 6 is 7 tons, the controller 10 sets the target excavated soil amount to 6 tons, as an example. In this case, the wheel loader 1 performs the excavation work five times and loads a total of 30 tons (=6 tons x 5 times) of earth and sand onto the dump truck.

In addition, in this example, the target excavated soil volume is set to the same value (equal) all five times, but it is not necessarily limited to this. For example, the controller 10 may set the target soil volume for the first four excavations to be 7 tons, which is the bucket capacity, and may set the target soil volume for the final excavation to be the remaining amount of 2 tons.

If the total amount of earth and sand to be loaded into the dump truck is less than or equal to the bucket capacity, the controller 10 may set the target excavated earth volume to be the same as the total amount of earth and sand. Alternatively, the controller 10 may set the target amount of excavated soil to be an amount obtained by dividing the total amount of earth and sand.

If it is determined that the input of the total amount of earth and sand has not been received (NO in step S3), the controller 10 advances the process to step S11. In step S11, the controller 10 determines whether an engine stop operation has been received. If the controller 10 determines that the engine stop operation has been received (YES in step S11), the controller 10 stops the engine 21 and ends the series of processes. If the controller 10 determines that the engine stop operation has not been received (NO in step S11), the process proceeds to step S2.

After step S4, the controller 10 determines in step S5 whether or not the accelerator operating member 81a has been operated. The controller 10 makes this determination based on the accelerator opening degree V1 detected by the accelerator operation detection section 81b.

If it is determined that the accelerator operation member 81a has been operated (YES in step S5), the controller 10 determines in step S6 whether excavation work has been started. The controller 10 determines whether excavation work has started based on the boom angle, the angle of the cutting edge of the bucket 6, the boom bottom pressure, the vehicle speed, and the stroke of the operating lever of the boom 14. If it is determined that the accelerator operation member 81a is not operated (NO in step S5), the controller 10 advances the process to step S2.

If it is determined that the excavation work has started (YES in step S6), the controller 10 automatically controls the work machine operation and the accelerator operation in step S7. In the automatic control, the controller 10 automatically controls the attitude of the work equipment 3, and also controls the running of the wheel loader 1 (vehicle speed ) is automatically controlled. Note that during the automatic control from step S7 to step S10, which will be described later, the operator operates the accelerator operating member 81a (accelerator operation). While the accelerator operation is being performed, the controller 10 automatically controls the work machine operation and the accelerator operation. Details of the process in step S7 will be described later.

In step S8, the controller 10 determines whether the accelerator operating member 81a is being operated. The controller 10 determines whether the accelerator operating member 81a is being continuously depressed. The controller 10 determines whether an accelerator operation is being performed based on the accelerator opening degree V1 detected by the accelerator operation detection section 81b. If it is determined that the accelerator operation member 81a is being operated (YES in step S8), the controller 10 determines in step S9 whether the bell crank angle θ2 has reached the maximum. The state in which the bell crank angle θ2 is at its maximum indicates that the target amount of excavated soil has been scooped into the bucket 6 and the excavation process has been completed.

If it is determined that the operator has not operated the accelerator operating member 81a (NO in step S8), the controller 10 ends the automatic control of the work machine operation and the accelerator operation in step S10. When the operator finishes operating the accelerator operating member 81a, the controller 10 ends automatic control and shifts to manual control (step S2) on the condition that no operation to stop the engine 21 is received.

If it is determined that the bell crank angle θ2 has reached the maximum (YES in step S9), the controller 10 advances the process to step S10. If it is determined that the bell crank angle θ2 is not the maximum (NO in step S9), the controller 10 advances the process to step S7.

In this way, the controller 10 determines whether the accelerator operation is not being performed based on the accelerator opening degree V1 detected by the accelerator operation detection unit 81b, or when the angle of the bell crank 18 with respect to the boom 14 has reached the maximum. In this case, the control of the operation of the working machine 3 using the learned model 180 and the control of the operation of the vehicle body 20 based on the calculated accelerator opening are ended. The case where it is determined that the accelerator operation is not performed means the case where the accelerator opening degree V1 becomes less than or equal to a predetermined value.

The flow of processing executed by the wheel loader 1 is not limited to that shown in FIG. 5. FIG. 6 is a flow diagram for explaining a modified example of the flow of processing executed by the wheel loader 1. As shown in FIG. As shown in FIG. 6, after step S7, the controller 10 executes the same process as step S9 in FIG. 5 as step S8A. After step S8A, the controller 10 executes the same process as step S8 in FIG. 5 as step S9A.

Specifically, if a positive determination is made in step S8A (YES in step S8A), the controller 10 advances the process to step S10. If a negative determination is made in step S8A (NO in step S8A), the controller 10 advances the process to step S9A. If a positive determination is made in step S9A (YES in step S9A), the controller 10 advances the process to step S7. If a negative determination is made in step S9A (NO in step S9A), the controller 10 advances the process to step S10.

In this manner, in this modification, the controller 10 performs steps S8 and S9 in FIG. 5 in reverse order. The processing shown in FIG. 6 also provides the same effect as the processing shown in FIG. 5.

(d2: automatic control)
Below, the above-mentioned automatic control of work machine operation and accelerator operation by the controller 10 (step S7 in FIG. 5) will be explained in detail.

FIG. 7 is a diagram for explaining calculations executed by the controller 10. As shown in FIG. 7, the controller 10 includes a learned model 180 and a calculation unit 280 that executes a predetermined program. The learned model 180 and the program are stored in advance in the memory 10M.

Trained model 180 includes a neural network. The neural network includes an input layer 181, an intermediate layer (hidden layer) 182, and an output layer 183. The intermediate layer 182 is multilayered.

The trained model 180 is an artificial intelligence for determining the target posture of the working machine 3 during excavation work. The learned model 180 calculates a target posture from the mechanical data regarding the operation of the vehicle body 20 and the working machine 3 acquired by the acquisition unit 170. The learned model 180 is learned (configured) to output, as a target attitude, a posture that allows the bucket 6 to scoop up the excavated object 100 by the bucket capacity (that is, the maximum capacity of the bucket 6).

Specifically, the learned model 180 calculates the amount of change Δθ1 of boom angle θ1 per unit time and the amount of change Δθ1 of bell crank angle θ2 per unit time based on boom cylinder pressure, vehicle speed, engine speed, and tractive force. The amount of change Δθ2 is calculated. Specifically, boom cylinder pressure, vehicle speed, engine speed, and tractive force are input to the learned model 180 at every predetermined control period T, and as an estimation result, the change in boom angle θ1 per unit time is calculated. The learned model 180 outputs the amount Δθ1 and the amount of change Δθ2 per unit time in the bell crank angle θ2.

The controller 10 controls the attitude of the working machine 3 based on the calculated changes Δθ1 and Δθ2. Specifically, the controller 10 controls the attitude of the boom 14 based on the amount of change Δθ1. The controller 10 controls the attitude of the bucket 6 based on the amount of change Δθ2.

The trained model 180 is generated using a training data set. The learning data set includes a plurality of learning data. Each learning data includes boom cylinder pressure, vehicle speed, engine rotation speed, and traction force as input data, and as correct data (teacher data), change amount Δθ1 of boom angle θ1 per unit time, and bell This includes the amount of change Δθ2 of the crank angle θ2 per unit time.

The parameters of the learning model are sequentially updated based on the error between the output obtained when input data is input to the learning model and the correct data. Note that the parameters are updated using a learning program. By repeating such update work (learning), a trained model 180 is generated. Specifically, the learned model 180 is created from data for the same vehicle class and the same quality of earth and sand. Note that generation of the learned model may be performed by the controller of the wheel loader, or may be performed by an external computer.

The calculation unit 280 calculates the accelerator opening degree (hereinafter also referred to as "accelerator opening degree V2") based on the target excavated soil volume. When the target excavated soil volume is input, the calculation unit 280 outputs the accelerator opening degree V2. Specifically, when the target excavated soil volume is specified, the calculation unit 280 calculates the accelerator opening degree V2 necessary for excavating the target excavated soil volume.

The calculation unit 280 calculates the accelerator opening degree V2 necessary for excavating the target excavated soil volume, based on a predetermined algorithm, in addition to the accelerator opening degree V1 detected by the accelerator operation detection unit 81b. The calculation unit 280 sequentially receives the accelerator opening degree V1 from the accelerator operation detection unit 81b, and separately calculates the accelerator opening degree V2 necessary for excavating the target excavated soil volume. The "accelerator opening degree V2 required for excavating the target excavated soil volume" refers to the accelerator opening degree that the controller 10 should originally receive from the accelerator operation detection unit 81b (the accelerator opening degree V2 required for excavating the target excavated soil volume) means the amount of accelerator operation to be performed).

One accelerator opening degree V2 (constant value) is calculated for one target excavated earth volume. For example, the value u1 (0<u1≦1) is calculated as the accelerator opening V2 for a target excavated soil volume of 6 tons, and the numerical value u2 (0<u2<u1) is calculated as the accelerator opening V2 for a target excavated soil volume of 2 tons. It is calculated as

FIG. 8 is a diagram schematically showing the processing executed by the calculation unit 280. As shown in FIG. 8, the calculation unit 280 includes an average boom bottom pressure calculation unit 281, an average tractive force calculation unit 282, and an accelerator opening calculation unit 283. Similar to the learned model 180, the calculation unit 280 is created from data for the same vehicle class and the same quality of earth and sand.

The average boom bottom pressure calculation unit 281 calculates the average boom bottom pressure (Mpa) when the target excavated earth volume (ton) is specified (input). Specifically, the average boom bottom pressure calculation unit 281 uses a function (y = ax ² + bx + c ... (f1)) that indicates the relationship between the target excavated earth volume (x) and the average boom bottom pressure (y). , the average boom bottom pressure (hereinafter also referred to as "target boom cylinder pressure") is calculated from the target excavated soil volume. The average boom bottom pressure calculation unit 281 sends the calculated average boom bottom pressure to the average traction force calculation unit 282 and the accelerator opening calculation unit 283.

The above function f1 is based on tens of thousands of pieces of data (the amount of excavated soil (more specifically, the measured value by a payload meter)) obtained by a vehicle of the same size as the wheel loader 1 for the same quality of soil, and the corresponding This is a function generated using the least squares method based on the average value of boom bottom pressure during excavation volume. Note that the black circles in the graph represent each data.

The average traction force calculation unit 282 calculates the average traction force (N) when the average boom bottom pressure (ton) is input. Specifically, the average traction force calculation unit 282 uses a function (y=a'x ² +b'x+c'...(f2)) indicating the relationship between the average boom bottom pressure (x) and the average traction force (y). Then, the average traction force (hereinafter also referred to as "target traction force") is calculated from the average boom bottom pressure. The average traction force calculation unit 282 sends the calculated average traction force to the accelerator opening calculation unit 283.

The above function f2 is based on tens of thousands of pieces of data (the average value of the boom bottom pressure during excavation work, the average value of the boom bottom pressure during excavation work, This is a function generated using the least squares method based on the average traction force of Note that the black circles in the graph represent each data.

The accelerator opening calculation unit 283 calculates the accelerator opening V2 when the average boom bottom pressure and the average tractive force are input. Specifically, the accelerator opening calculation unit 283 uses a function (Z=Ax+By...(f3)) that indicates the relationship between the average boom bottom pressure (x), the average tractive force (y), and the accelerator opening (z). Then, the accelerator opening degree V2 is calculated from the average boom bottom pressure and the average traction force. Note that in this example, the average boom bottom pressure and the average tractive force are normalized. In this example, coefficients A and B are each greater than or equal to 0 and less than or equal to 1.

Coefficients A and B in the above function f3 are determined based on multiple regression analysis. In this way, the accelerator opening calculation unit 283 predicts the accelerator opening, which is one target variable, using the average boom bottom pressure and the average tractive force, which are a plurality of explanatory variables. Function f1, function f2, and function f3 are stored in memory 10M.

The accelerator opening calculation unit 283 outputs the calculated accelerator opening V2. In this case, the controller 10 controls the traveling of the vehicle body 20 based on the calculated accelerator opening degree V2. Thereby, the controller 10 travels (forwards) at a speed corresponding to the calculated accelerator opening degree V2.

The reason why the controller 10 calculates the accelerator opening degree V2 based on the target excavated soil volume as described above is as follows. As described above, the learned model 180 determines the attitude of the working machine 3 during excavation work. The controller 10 operates the work machine 3 so as to assume the determined posture.

By the way, the learned model 180 is configured such that the working machine 3 is in a posture that allows the bucket 6 to scoop up the excavated object 100 by the bucket capacity. Therefore, the controller 10 adjusts the amount of soil scooped by the bucket 6 by controlling the traveling (vehicle speed) of the vehicle body 20 based on the calculated accelerator opening degree V2.

Specifically, the controller 10 calculates the reduction ratio required by the transmission 23 in order to achieve the vehicle speed based on the calculated accelerator opening V2. The reduction ratio is obtained by calculating the ratio between the engine rotation speed determined by automatic control of the working machine 3 and the vehicle speed request determined by the calculated accelerator opening V2. By operating the transmission 23 at the reduction ratio, the amount of soil scooped by the bucket 6 is adjusted. In the wheel loader 1, the smaller the calculated accelerator opening degree V2, the smaller the amount of the excavated object 100 to be scooped.

Specifically, when the accelerator opening is small, the amount of penetration into the ground is also small. Therefore, the amount of earthwork for excavation (the amount of excavated earth) is low (see Figure 10). When the accelerator opening is large, the amount of penetration into the ground is also large. Therefore, the amount of earthwork required for excavation will be high (see Figure 9). In this way, the amount of excavated soil can be adjusted by adjusting the opening degree of the accelerator. Therefore, in the wheel loader 1, the target posture is the same regardless of the magnitude of the accelerator opening, and the amount of excavated soil can be freely adjusted by controlling the accelerator opening.

In the above description, the target posture determined by the learned model 180 is "a posture capable of scooping up the excavated object 100 equivalent to the bucket capacity." However, the target posture is only an example and is not limited thereto. For example, the target posture determined by the trained model 180 may be "a posture that can scoop up the excavated object 100 that is 90% of the bucket capacity" or "a posture that can scoop up the excavated object 100 that is 50% of the bucket capacity". .

Note that in the above, the calculation unit 280 calculated the throttle opening degree from the target excavated soil volume using the function f3 obtained by multiple regression analysis. However, the calculation unit 280 is not limited to this, and may be configured by a trained program (for example, a neural network).

(d3: excavation state)
FIG. 9 is a diagram for explaining excavation work when the calculated accelerator opening degree V2 is large (for example, "1"). As shown in FIG. 9, the wheel loader 1 causes the cutting edge 6a of the bucket 6 to bite into the excavated object 100, and then raises the bucket 6 along the bucket locus La, as indicated by the curved arrow in FIG. . As a result, the excavation work of scooping up the excavated object 100 into the bucket 6 is executed. In the case of this example, the wheel loader 1 is able to scoop up soil equivalent to the bucket capacity.

For example, if the bucket capacity is 7 tons and the specified (calculated) target excavated soil volume is 7 tons, the wheel loader 1 can scoop approximately 7 tons of earth and sand.

FIG. 10 is a diagram for explaining the excavation work when the calculated accelerator opening degree V2 is smaller than the accelerator opening degree V2 of FIG. 9. As shown in FIG. 10, the wheel loader 1 causes the cutting edge 6a of the bucket 6 to bite into the excavated object 100, and then raises the bucket 6 along the bucket trajectory Lb, as indicated by the curved arrow in FIG. . As a result, the excavation work of scooping up the excavated object 100 into the bucket 6 is executed. In the case of this example, the wheel loader 1 can scoop up a predetermined amount (for example, 2 tons) of earth and sand that is less than the bucket capacity.

In this way, the wheel loader 1 uses the learned model 180 to control the operation of the work equipment 3 so that the attitude of the work equipment 3 becomes the target attitude, and also controls the accelerator opening calculated based on the target excavated soil volume. By controlling the travel of the vehicle body 20 based on the degree V2, it becomes possible to excavate the amount of soil corresponding to the target amount of excavated soil.

<E. Experiment results＞
Hereinafter, the advantages of the wheel loader 1 will be specifically explained based on experimental results.

FIG. 11 is a diagram for explaining excavation accuracy by automatic control of work machine operation and accelerator operation. As shown in FIG. 11, when the target excavated soil volume is set to 7 tons, the average value of the soil volume excavated by the wheel loader 1 six times (the average value of the weight of soil detected by the payload meter) was 7.1 tons. The error in this case was 1.4% (=(7.1-7.0)/7.0×100). Note that the payload meter may be mounted on the wheel loader 1 in advance. Alternatively, the payload meter may be retrofitted to the wheel loader 1. Further, instead of the payload meter, a truck scale may be used to measure the weight of the excavated object 100.

Similarly, when the target excavated soil volume is 6.3 tons, 5.6 tons, 4.9 tons, 4.2 tons, and 3.5 tons, the errors are 0.0%, 1.8%, and 0.0, respectively. %, 2.4%, and 8.6%. In this way, it was confirmed that the error was within 10.0% in all cases.

Figure 12 shows the difference between when the total amount of earth and sand to be loaded into a dump truck is 18 tons, when excavation is performed by automatic control of work equipment operation and accelerator operation (automatic excavation), and when excavation is performed by manual operation (manual excavation). , is a diagram showing the amount of soil loaded into a dump truck and the loading accuracy for 10 times. FIG. 13 is a diagram showing the average value, cycle time, and fuel consumption of the data shown in FIG. 12. Note that the cycle time is the total value of three loading operations into the dump truck.

As shown in FIGS. 12 and 13, the automatic excavation described above can ensure the same amount of soil loading (corresponding to the amount of excavated soil) and loading accuracy as manual excavation. As shown in FIG. 13, automatic excavation can reduce cycle time compared to manual excavation by reducing reloading and tip-off operations. Additionally, automatic excavation reduces fuel consumption compared to manual excavation.

FIG. 14 is a diagram for further explaining fuel efficiency due to automatic control of work equipment operation and accelerator operation. As shown in FIG. 14, the fuel consumption of the wheel loader 1 was 66.5 ml when the target excavated soil volume was set to 7 tons. Similarly, when the target excavated soil volume is 6.3 tons, 5.6 tons, 4.9 tons, 4.2 tons, and 3.5 tons, the fuel consumption is 46.6 ml, 27.6 ml, 24.5 ml, and 23 tons, respectively. .9ml, 20.4ml.

As a result, for example, if the total amount of earth and sand to be loaded onto a dump truck is 11.2 tons, when digging 5.6 tons of earth and sand and loading it onto the dump truck, the total fuel consumption will be 55.2 ml (= 27.6 x 2 ). On the other hand, when 7.0 tons of earth and sand are excavated, and then 4.2 tons of earth and sand are excavated and loaded onto a dump truck, the total fuel consumption is 90.4 ml (=66.5+23.9).

As described above, it has been found that when calculating the target amount of excavated soil from the total amount of earth and sand to be loaded onto a dump truck, it is preferable to average the amount of excavated soil each time from the viewpoint of fuel efficiency.

<F. Summary＞
(1) The wheel loader 1 includes a vehicle body 20 that can travel, a work machine 3 that includes a bucket 6 and performs excavation work using the bucket 6, and a controller 10. The controller 10 includes a calculation unit 150 that acquires mechanical data regarding the operation of the vehicle body 20 and the work equipment 3, and calculates a target posture of the work equipment 3 during excavation work based on the machine data, and a calculation unit 150 that calculates a target posture of the work equipment 3 during excavation work, and a calculation unit 150 that acquires machine data regarding the operation of the vehicle body 20 and the work equipment 3. The calculation unit 280 calculates the necessary accelerator opening degree V2. In this example, the calculation unit 150 includes an acquisition unit 170 that acquires machine data, and a learned model 180 that calculates a target posture of a working machine during excavation work based on the machine data. The controller 10 controls the operation of the work machine 3 so that the attitude of the work machine 3 becomes a target attitude, and also controls the traveling of the vehicle body 20 based on the accelerator opening degree V2.

According to such a configuration, when the target excavated soil volume is specified, the accelerator opening degree V2 required for excavating the target excavated soil volume is calculated by the calculation unit 280. Therefore, the wheel loader 1 controls the operation of the work implement 3 so as to achieve the target posture obtained by the learned model 180, and travels based on the accelerator opening degree V2 calculated by the calculation unit 280. It becomes possible to automatically and accurately scoop out the specified target excavated soil volume.

Specifically, the target posture obtained by the learned model 180 is the same regardless of the magnitude of the accelerator opening V2. Even if the target posture is the same, the amount of soil excavated can be controlled by controlling the amount of penetration of the bucket 6 into the ground, that is, the opening degree of the accelerator. Typically, the amount of excavated soil changes depending on the amount of penetration into the ground, that is, the accelerator opening (vehicle speed) and the speed of the work machine. However, in the configuration of this embodiment, the target posture controlled by the learned model 180 also includes control of the work machine speed. In other words, if the target posture is the same, the change in work machine speed is also the same. Therefore, the amount of excavated soil can be controlled only by controlling the accelerator opening (vehicle speed). Strictly speaking, the working machine speed determined by the learned model 180 also changes depending on the vehicle speed. Specifically, it is determined that the lower the vehicle speed, the higher the work machine speed. However, since the work machine speed is also affected by variables other than vehicle speed (boom cylinder pressure, engine speed, traction force), the change in work machine speed with respect to changes in vehicle speed is small. In other words, the change in the amount of excavation into the ground with respect to a change in vehicle speed is greater than the change in the working machine speed with respect to a change in vehicle speed. Therefore, the amount of excavated soil can be controlled by the accelerator opening (vehicle speed). Further, accuracy can be further improved by making corrections that take into account changes in work machine speed with respect to changes in vehicle speed. Specifically, the correction can be made in the same manner as in the modification example in which the soil quality is changed, which will be described later. As described above, even if the target posture of the working machine 3 is the same, the amount of excavated soil can be freely controlled by the accelerator opening degree. In this way, by controlling the accelerator opening degree V2, the amount of excavated soil can be adjusted.

(2) The work machine 3 includes a boom 14 and a boom cylinder 16 that operates the boom 14. As explained based on FIG. 8, the calculation unit 280 calculates the target boom cylinder pressure to be applied to the boom cylinder 16 and the target traction force of the wheel loader 1 based on the target excavated soil volume. The calculation unit 280 calculates the accelerator opening degree V2 based on the target boom cylinder pressure and the target traction force. According to such a configuration, the controller 10 can calculate the accelerator opening degree V2 from the target excavated soil volume.

(3) The vehicle body 20 further includes an engine 21. The mechanical data includes the pressure of the boom cylinder 16, the vehicle speed of the wheel loader 1, the rotational speed of the engine 21, and the tractive force of the wheel loader 1. According to such a configuration, the learned model 180 can output the target posture of the working machine 3 using only four input parameters.

(4) The work machine 3 further includes a bell crank 18 that rotatably supports the boom 14. The controller 10 performs learning when it is determined that the accelerator is not operated based on the accelerator opening degree V1 detected by the accelerator operation detection unit 81b, or when the angle of the bell crank 18 with respect to the boom 14 reaches the maximum. The control of the operation of the working machine 3 using the completed model 180 and the control of the operation of the vehicle body 20 based on the calculated accelerator opening degree V2 are ended.

According to such a configuration, it is possible to determine the end of one excavation operation. Furthermore, it is possible to terminate the control of the operation of the work implement 3 using the learned model 180 and the control of the operation of the vehicle body 20 based on the calculated accelerator opening degree V2 based on the determination of completion of one excavation operation. can.

(5) The controller 10 receives an input of the total weight of earth and sand (excavated object) to be loaded into a dump truck via an input device such as the operation key 51. When the total weight is greater than the bucket capacity, the controller 10 divides the total weight into multiple weights that are less than or equal to the bucket capacity. The controller 10 (specifically, the calculation unit 280) calculates the accelerator opening degree V2 using the weight obtained by the division as the target excavated soil volume. According to such a configuration, when the total weight of earth and sand to be loaded into a dump truck is input, the target excavated earth volume is calculated. Therefore, the operator need only input the total weight.

(6) Preferably, the controller 10 divides the total weight evenly. According to such a configuration, the fuel consumption of the wheel loader 1 can be reduced compared to the case where the total weight is not divided equally.

<G. Modified example>
(1) If the quality of the earth and sand to be excavated changes, it is assumed that the accuracy of the calculation unit 280 will decrease. For example, when the target excavated soil volume is specified as 3 tons, it is possible that 4 tons of earth and sand will be excavated. Therefore, the configuration of the calculation unit 280 having an adjustment function (tuning function) capable of outputting the accelerator opening degree V2 according to the quality of the earth and sand will be explained. Hereinafter, the calculation unit 280 having such an adjustment function will be referred to as a calculation unit 280A for convenience of explanation.

FIG. 15 is a functional block diagram for explaining the functional configuration of the calculation unit 280A. The calculation unit 280A includes an average boom bottom pressure calculation unit 281, an average tractive force calculation unit 282, an accelerator opening calculation unit 283, and a correction unit 284. The calculation unit 280A differs from the calculation unit 280 (see FIG. 8) in that it includes a correction unit 284.

First, generation of a correction formula by the correction unit 284 will be explained. After that, the correction of the target excavated earth volume using the correction formula by the correction unit 284 will be explained.

The target excavated earth volume and the weight (measured value) of earth and sand detected by the payload meter 99 mounted on the wheel loader 1 are input to the correction unit 284 . The correction unit 284 generates a correction formula using the target excavated soil volume and the actual excavated soil volume (measured value). Specifically, the correction unit 284 generates a correction formula using three data (specifically, three coordinate values (x1, y1), (x2, y2), (x3, y3)), which will be described later. . Note that the payload meter 99 is an example of a detection unit that detects the weight of the excavation object 100 loaded into the bucket 6. Payload meter 99 may be mounted on wheel loader 1 in advance. Alternatively, the payload meter 99 may be retrofitted to the wheel loader 1.

FIG. 16 is a flow diagram for explaining the flow of generating a correction formula. FIG. 17 is a diagram for explaining the relationship between the target excavated soil volume used when generating the correction formula and the measured value by the payload meter 99.

As shown in FIG. 17, as a premise for generating the correction formula, the controller 10 uses a coordinate system in which the target excavated soil volume is the X-coordinate value and the measured value by the payload meter 99 is the Y-coordinate value.

As shown in FIG. 16, in step S31, the controller 10 sets the target excavated soil volume to the first soil volume (x1) (see FIG. 17) and performs the excavation work by the automatic control described above ("accelerator opening :small"). In step S32, the controller 10 acquires the measured value (y1) by the payload meter 99 (see FIG. 17) when the target excavated soil volume is the first soil volume (x1).

In step S33, the controller 10 sets the target excavated soil volume to the second soil volume (x2) (>x1) and performs the excavation work under automatic control described above. In this case, the accelerator opening is larger (“accelerator opening: medium”) than when the target excavated soil volume is the first soil volume (x1). In step S34, the controller 10 acquires the measured value (y2) by the payload meter 99 when the target excavated soil volume is the second soil volume (x2).

In step S35, the controller 10 sets the target excavated soil volume to the third soil volume (x3) (>x2) and performs the excavation work under the automatic control described above. In this case, the accelerator opening is larger (“accelerator opening: large”) than when the target excavated soil volume is the second soil volume (x2). In step S36, the controller 10 obtains the measured value (y3) by the payload meter 99 when the target excavated soil volume is the third soil volume (x3).

In step S37, the controller 10 calculates the function (x=αy ² +βy+γ ... (f4)) using the least squares method based on the three coordinate values (x1, y1), (x2, y2), (x3, y3). generate.

The first volume of soil (x1), the second volume of soil (x2), and the third volume of soil (x3) may be determined by the controller 10 as appropriate. Further, the function f4 may be generated using two or less volumes (for example, x1, x2) or four or more volumes (x1, x2, x3, x4, . . . ).

After generating the function f4 described above, the correction unit 284 stores the function f4. After this, actual operation using the function f4 is performed. Although details will be described later, the correction unit 284 uses the function f4 to correct the input target excavated soil volume. The correction unit 284 sends the corrected target excavated soil volume to the average boom bottom pressure calculation unit 281. Note that during actual operation, the calculation unit 280A does not use the measured value by the payload meter 99 when calculating the accelerator opening degree V2.

The average boom bottom pressure calculation unit 281 calculates the average boom bottom pressure using the above-mentioned function f1 based on the corrected target excavated soil volume. The average boom bottom pressure calculation unit 281 sends the average boom bottom pressure to the average traction force calculation unit 282 and the accelerator opening calculation unit 283. The processing in the average traction force calculation section 282 and the processing in the accelerator opening calculation section 283 have already been explained, so they will not be described repeatedly here. As described above, information on the accelerator opening degree V2 is output from the calculation unit 280A.

A specific explanation of the correction processing by the correction unit 284 is as follows. FIG. 18 is a flowchart for explaining a series of processing steps from inputting the total amount of earth and sand to be loaded onto a dump truck to correction by the correction unit 284. As shown in FIG. 18, in step S31, the controller 10 receives an input of the total amount of earth and sand to be loaded onto the dump truck based on an input operation by an operator. In step S32, the controller 10 calculates a target amount of excavated soil (amount of soil per one excavation).

In step S33, the controller 10 (specifically, the correction unit 284) inputs the value of the target excavated earth volume calculated in step S32 into y of the function f4 (x=αy ² +βy+γ), thereby determining the value of x. Calculate. In step S34, the controller 10 (specifically, the correction unit 284) sets the value of x to the target excavated soil volume (corrected target excavated soil volume).

When generating the function f4, x is set to the value of the target amount of excavated earth, but when performing correction, y is set to the value of the target amount of excavated earth as described above. The target excavated soil volume is input into y of the function f4 as an inverse function. Thereby, the corrected target excavated soil volume is obtained as the value of x.

A simplified specific example will be explained as follows. For example, suppose the three coordinate values (x1, y1), (x2, y2), (x3, y3) are (4, 5), (6, 7.5), (8, 10), respectively. . In this way, it is assumed that 1.25 times more earth and sand is being excavated than the target excavated earth volume. In other words, assume that the target excavated soil volume is 0.8 times the actual excavated soil volume.

In this case, x=0.8y is obtained as the function f4. When the target excavated soil volume is 7.5 tons in actual operation, 7.5 is substituted for y, and 6 tons is obtained as the corrected target excavated soil volume (x). In this way, by correcting (adjusting) the target excavated earth volume from 7.5 tons to 6 tons, it is possible to scoop up 7.5 tons of earth and sand as a result. By adjusting the target excavated soil volume input to the calculation unit 280A, it becomes possible to excavate earth and sand corresponding to the target excavated soil volume input to the calculation unit 280A.

This correction is not limited to a decrease in accuracy of the calculation unit 280 due to a change in the quality of the earth and sand. This correction can also be applied to a decrease in accuracy of the calculation unit 280 due to a change in the control method of the vehicle body 20. Typically, the amount of soil excavated is determined by the amount of penetration into the ground and the speed of the work equipment. For example, when control is performed to change the speed of the working machine depending on the vehicle speed, it is possible that the amount of excavated soil cannot be accurately controlled only by controlling the accelerator opening (vehicle speed). Even in such a case, this correction can optimize the relationship between the accelerator opening degree and the amount of excavated soil, and improve the accuracy of the amount of excavated soil. In other words, according to this correction, it is possible to improve the decrease in accuracy of the calculation unit 280 due to a change in the control method of the vehicle body 20.

As described above, the wheel loader 1 includes the payload meter 99 that detects the weight of the excavated object 100 loaded into the bucket 6. The controller 10 includes a correction unit 284 that corrects the target excavated soil volume based on the difference between the target excavated soil volume and the weight detected by the payload meter 99. The calculation unit 280A calculates the opening degree of the accelerator based on the corrected target excavated soil volume. This enables control according to the soil quality of the excavated object 100.

(2) In the above description, an HMT (Hydraulic Mechanical Transmission) type wheel loader utilizing electronic control has been exemplified as the wheel loader 1, but the present invention is not limited to this. Even with a torque converter type wheel loader, the amount of soil excavated can be controlled by the accelerator opening (vehicle speed), so the above-mentioned automatic control can also be applied to a torque converter type wheel loader. This point will be explained in detail as follows.

In a torque converter type wheel loader, when the target excavation volume is small, the accelerator opening (vehicle speed) is lowered to reduce the amount of penetration into the ground. In order to reduce the amount of excavated soil, it is preferable to have a high working machine speed, but this type of control is not possible with a torque converter type wheel loader. However, since the effect of reducing the amount of penetration into the ground is greater than the effect of reducing the speed of the work equipment by lowering the vehicle speed (accelerator opening), the amount of excavated soil can be adjusted even with a torque converter type wheel loader.

Furthermore, the accuracy of excavated soil volume can be further improved by making a correction that takes into account the effect of a decrease in the work machine speed due to a decrease in vehicle speed (accelerator opening degree). This correction can be made in the same way as the method used to improve the accuracy of the calculation unit 280 due to a change in the control method of the vehicle body 20.

In this way, by controlling the accelerator opening degree, the amount of excavated soil can be controlled. Furthermore, even if the operation of the work equipment 3 does not change, if the amount of penetration into the ground when changing the accelerator opening can be adjusted (if the relationship between the accelerator opening and the amount of soil that can be excavated can be corrected), the excavated soil The accuracy of quantity can be further improved.

(3) In the above description, a configuration has been described in which the working machine operation and the accelerator operation are automatically controlled only while the accelerator operating member 81a is being operated. Specifically, as shown in steps S5 to S7 in FIG. 5, for example, based on the fact that the start of excavation work is detected while the accelerator operating member 81a is being operated, the controller 10 controls the work equipment operation and the accelerator operation. The configuration for starting automatic control with Further, as shown in steps S8 and S10 in FIG. 5, for example, based on the determination that the accelerator operation member 81a is not operated (accelerator operation), the controller 10 automatically controls the work equipment operation and the accelerator operation. The configuration for terminating control has been explained. However, the timings for starting and ending automatic control are not limited to such conditions. The controller 10 may start or end automatic control based on predetermined logic (timing) or predetermined lever operation.

(4) The loading target is not limited to dump trucks. Loading targets are not limited to self-propelled vehicles. For example, the object to be loaded may be a vehicle to be towed. In the earth removal process, the excavated object 100 may be simply discharged to a predetermined location.

(5) In the above, a configuration has been described in which the target posture is calculated using the learned model 180 that is artificial intelligence. However, if the amount of penetration into the ground can be adjusted by accelerator control for a certain work machine control (position control, load control, etc.), it is not necessarily necessary to use artificial intelligence to calculate the target posture.

The controller 10 may calculate the target posture using calculation logic (calculation logic) created in advance. For example, the controller 10 may determine the target posture based on the load that the work machine 3 receives. The controller 10 may control the work implement 3 according to a predetermined target posture with respect to a change in boom cylinder pressure that changes due to a reaction force from the earth. Specifically, the amount of change Δθ1 of the boom angle θ1 per unit time and the amount of change Δθ2 of the bell crank angle θ2 per unit time with respect to the boom cylinder pressure are stored in the memory 10M, and the controller 10 The working machine 3 may be controlled based on the amounts of change θ1 and θ2.

Note that the method for detecting the load applied to the working machine 3 is not limited to detecting boom cylinder pressure. For example, if a strain sensor or a torque sensor is installed in the work machine 3, the sensor detects the load that the work machine 3 receives from the ground, and the controller 10 controls the work machine 3 based on the detection result. good.

(6) When calculating the target posture using the trained model 180 as described above, the controller 10 starts calculating the target posture before the start of the excavation work, and It merely serves as a trigger to control aircraft 3 to its target attitude. Therefore, the timing between the detection of the start of excavation work and the start of calculation of the target attitude does not matter. That is, the controller 10 may first calculate the target attitude, then detect the start of the excavation work, and then control the vehicle body 20 so as to attain the target attitude. Conversely, the controller 10 may calculate the target posture after detecting the start of the excavation work, and may control the vehicle body 20 so as to adopt the target posture. Even when the above-mentioned calculation logic is used instead of the learned model 180, it does not matter whether the detection of the start of excavation work or the start of calculation of the target posture occurs in time.

(7) In the above configuration, all the controls are executed by the controller 10, but some or all of the controls may be executed by an external controller. For example, during automatic excavation, the wheel loader 1 may be operated by sending an operating voltage (operating signal) from an external controller such as an edge terminal, and receiving the operating signal at the controller 10. During work other than automatic excavation, the value detected by the sensor that reads the voltage value of lever operation is constantly read by an external controller (not shown), and the wheel loader 1 is operated by sending a signal indicating the value to the controller 10. may be done.

For example, by incorporating automatic excavation logic into the controller 10 built into the vehicle body 20, the wheel loader 1 may be controlled without applying a signal from an external controller. Further, the present technology may also be applied by sending a signal from an external controller to directly open and close the valve without going through the controller 10.

The embodiment disclosed this time is an example, and is not limited to the above content only. The scope of the present invention is indicated by the claims, and it is intended that all changes within the meaning and range equivalent to the claims are included.

1 wheel loader, 2 body frame, 2a front frame, 2b rear frame, 2b frame, 2ton, 6ton target excavated soil volume, 3 work equipment, 4 traveling device, 4a front wheel, 4a wheel, 5 cab, 6 bucket, 6a cutting edge, 6b back side, 8 operating device, 9 boom pin, 10 controller, 10M memory, 11 steering cylinder, 13 work equipment pump, 14 boom, 15 link, 16 boom cylinder, 17 bucket pin, 18 bell crank, 18a support pin, 18b, 18c Connection pin, 19 Bucket cylinder, 20 Vehicle body, 21 Engine, 23 Transmission, 27 Input shaft, 28 Output shaft, 29 First angle detector, 32 Axle, 33 Power take-off part, 34 Work equipment valve, 48 Second angle detector , 50 display, 51 operation key, 81a accelerator operation member, 81b accelerator operation detection section, 83a boom operation member, 83b boom operation detection section, 84a bucket operation member, 84b bucket operation detection section, 85b shift operation detection section, 91 engine rotation Number sensor, 92 Output rotation speed sensor, 95 First oil pressure detector, 96 Second oil pressure detector, 99 Payload meter, 100 Excavation target, 150, 280, 280A Calculation unit, 170 Acquisition unit, 180 Learned model, 181 Input layer, 182 Intermediate layer, 183 Output layer, 231 Planetary gear, 232, 233 Hydraulic motor, 281 Average boom bottom pressure calculation section, 282 Average tractive force calculation section, 283 Accelerator opening calculation section, 284 Correction section, H Horizontal line, L , La, Lb bucket locus, P boom reference line, Q bell crank reference line.

Claims (9)

A vehicle body that can run, a work machine that includes a bucket and performs excavation work using the bucket, and a controller,
The controller includes:
a first calculation unit that acquires mechanical data regarding the operation of the vehicle body and the working machine, and calculates a target posture of the working machine during excavation work based on the machine data;
and a second calculation means for calculating the accelerator opening degree necessary for excavating the target excavated soil volume,
A working machine that controls the operation of the working machine so that the attitude of the working machine becomes the target attitude, and also controls the running of the vehicle body based on the accelerator opening degree. The work machine includes a boom and a boom cylinder that operates the boom,
The second calculation means is
Based on the target excavated earth volume, calculate a target boom cylinder pressure to be applied to the boom cylinder and a target traction force of the working machine,
The working machine according to claim 1, wherein the accelerator opening degree is calculated based on the target boom cylinder pressure and the target tractive force. the bucket is connected to the boom;
The working machine further includes a detection means for detecting the weight of the excavated object loaded into the bucket,
The controller further includes a correction means for correcting the target excavated soil volume based on the difference between the target excavated soil volume and the detected weight,
The working machine according to claim 2, wherein the second calculation means calculates the accelerator opening degree based on the corrected target excavated soil volume. The vehicle body further includes an engine,
The working machine according to claim 2 or 3, wherein the machine data is the pressure of the boom cylinder, the vehicle speed of the working machine, the rotation speed of the engine, and the tractive force of the working machine. The work machine further includes a bell crank that rotatably supports the boom,
The controller controls the operation of the work equipment when the accelerator is not operated or when the angle of the bell crank with respect to the boom reaches a maximum, and controls the operation of the vehicle body based on the accelerator opening degree. The work machine according to any one of claims 2 to 4, wherein the control is terminated. further comprising an input device that accepts an input of the total weight of the excavated object to be loaded onto the loading object,
If the total weight is greater than the bucket capacity, the controller divides the total weight into multiple weights that are less than or equal to the bucket capacity;
The working machine according to any one of claims 1 to 5, wherein the second calculation means calculates the accelerator opening degree using the weight obtained by division as the target excavated soil volume. 7. The work machine of claim 6, wherein the controller divides the total weight equally. The first calculation means includes a learned model that receives the machine data as input and outputs the target posture,
The operation according to any one of claims 1 to 7, wherein the learned model is trained to output, as the target attitude, a posture that allows the bucket to scoop up an excavated object equivalent to the bucket capacity. machine. A method for controlling a working machine including a movable vehicle body and a working machine having a bucket, the method comprising:
acquiring mechanical data regarding the operation of the vehicle body and the working machine, and calculating a target posture of the working machine during excavation work based on the machine data;
a step of calculating the accelerator opening degree necessary for excavating the target excavated soil volume;
A method for controlling a working machine, comprising: controlling the operation of the working machine so that the attitude of the working machine becomes the target attitude, and controlling the running of the vehicle body based on the accelerator opening degree.

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