CONTROL SYSTEM FOR EXCAVATOR AND EXCAVATOR

CROSS-REFERENCE TO RELATED APPLICATION

The present application is based on and claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2023-216248, filed on Dec. 21, 2023, the contents of which are incorporated herein by reference in their entirety.

BACKGROUND
Technical Field

The present invention relates to a control system of an excavator and an excavator.

Description of Related Art

Conventionally, excavators have been used in various work sites. Therefore, excavators often travel on slopes.

SUMMARY

A control system for an excavator includes the excavator including a lower traveling body, and an upper turning body mounted rotatably with respect to the lower traveling body; an inclination recognition device configured to recognize an inclination of a ground on which the excavator is traveling; and a control part configured to control the lower traveling body such that an inclination of a traveling direction of the excavator with respect to an inclined direction of the ground is within a predetermined angle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram illustrating an example of the configuration of a remote control system for an excavator according to a first embodiment;

FIG. 2 is a side view of an excavator according to the first embodiment;

FIG. 3 is a block diagram illustrating an example of the hardware configuration of an excavator and a remote control room according to the first embodiment;

FIG. 4 is a functional block diagram illustrating an example of the configuration of a remote control system according to the first embodiment;

FIG. 5 is an explanatory diagram illustrating control of the lower traveling body of an excavator by a controller according to the first embodiment;

FIG. 6 is a flowchart illustrating a processing procedure for causing an excavator to travel on an inclined ground by the controller according to the first embodiment;

FIG. 7 is an explanatory diagram illustrating a travel trajectory of a crawler when the controller according to the first embodiment controls the lower traveling body;

FIG. 8 is a flowchart illustrating a processing procedure for the controller according to the first embodiment to move the excavator 100 before the inclination of the ground is switched; and

FIG. 9 is an explanatory diagram illustrating the travel trajectory of the crawler when the controller according to the first embodiment controls the lower traveling body.

DETAILED DESCRIPTION

In a conventional technology, the tip of a front work machine is brought into contact with the ground during climbing or downhill traveling, thereby preventing an overturn and performing a smooth traveling operation. However, the technology for preventing an overturn is not described in the conventional technology, and other techniques may be used.

In an aspect of the present invention, a technology for improving safety by controlling a lower traveling body is proposed.

According to one aspect of the present invention, safety is improved by controlling a lower traveling body when the traveling direction of the excavator is inclined with respect to the inclined direction of the ground.

Embodiments of the present invention will be described below with reference to the drawings. Further, the embodiments described below are not intended to limit the present invention but are examples, and all features and combinations thereof described in the embodiments are not necessarily essential to the present invention. Further, the same or corresponding components in the respective drawings are denoted by the same or corresponding reference numerals, and explanations may be omitted.

In the embodiments of the present invention, an example of using an excavator as an example of a work machine will be described below, but the present invention is not limited to an excavator. The embodiment may be applied to a construction machine, a standard machine, an application machine, a forestry machine, or a conveying machine based on a hydraulic excavator.

First Embodiment

In the first embodiment, a case where an operator remotely operates the excavator 100 will be described.

FIG. 1 is a schematic diagram illustrating an example of the configuration of the remote control system (an example of a control system for an excavator) SYS for the excavator 100 according to the present embodiment. In the example illustrated in FIG. 1, the excavator 100 and the remote control room RC are connected via a communication line NW. Thus, transmission and reception of information can be implemented between the excavator 100 and the remote control room RC.

The excavator 100 transmits detection results from various sensors provided in the excavator 100 to the remote control room RC by using the communication device T1 (see FIG. 3) provided in the excavator 100. For example, the excavator 100 transmits image information captured by an imaging device S6 (see FIG. 3) to the remote control room RC.

The remote control system SYS according to the present embodiment is provided with a remote control room RC. The remote control room RC is provided with a display device DR, an operation device R26, an operation sensor R29, an operation seat DS, a remote controller R30, and a communication device T2.

The display device DR is provided for the operator OP in the remote control room RC to visually check the vicinity of the excavator 100.

The operator OP in the operation seat DS of the remote control room RC performs an operation on the operation device R26. The operation sensor R29 detects the operation contents received by the operation device R26. The remote controller R30 generates an operation signal corresponding to the operation contents.

Then, the communication device T2 transmits the generated operation signal to the excavator 100. The remote controller R30 transmits the operation signal to enable remote control of the excavator 100.

The operator OP can identify the surroundings of the excavator 100 by referring to the image information displayed on the display device DR. However, with the image information displayed on the display device DR, it may be difficult to identify the surroundings of the excavator 100 compared with the case of actually visually recognizing the surroundings from the excavator 100. For example, it is difficult for the operator OP to identify the inclination of the ground where the excavator 100 is traveling and the condition of the crawler of the excavator 100.

Therefore, in the remote control system SYS according to the present embodiment, when there is an inclination of the ground, control for preventing the overturn of the excavator 100 due to the inclination, is implemented.

First, an outline of the excavator 100 according to the present embodiment will be described with reference to FIG. 2. FIG. 2 is a side view of the excavator 100 according to the present embodiment.

The excavator 100 according to the present embodiment is provided with a lower traveling body 1; an upper turning body 3 mounted on the lower traveling body 1 in a freely turning manner via a turning mechanism 2; a boom 4, an arm 5, and a bucket 6 as an attachment AT; and a cabin 10.

The lower traveling body 1 (an example of a traveling body) includes, for example, a pair of right and left crawlers, and the respective crawlers are hydraulically driven by the traveling hydraulic motors 1ML and 1MR (see FIG. 3) to move the excavator 100.

The upper turning body 3 (an example of a turning body) is driven by the turning hydraulic motor 2M (see FIG. 3) to turn with respect to the lower traveling body 1.

The attachment AT (an example of an attachment) includes a boom 4, an arm 5, and a bucket 6.

The boom 4 is mounted to the front center of the upper turning body 3 so as to turn upward and downward, the arm 5 is mounted to the tip of the boom 4 in such a manner that it can be vertically rotated, and the bucket 6 is mounted to the tip of the arm 5 in such a manner that it can be vertically rotated.

The bucket 6 is an example of a working tool. The bucket 6 is used, for example, for excavation work. The bucket 6 according to the present embodiment has a toe 6a and a back surface 6b as parts for forming a horizontal plane.

Further, other working tools may be attached to the tip of the arm 5 in place of the bucket 6 according to the contents of work. The other working tools may be other types of buckets such as large buckets, slope buckets, and dredger buckets. The other working tools may be other types of working tools other than buckets such as agitators, breakers, and grapples.

The boom 4, the arm 5, and the bucket 6 are hydraulically driven by the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 as hydraulic actuators with hydraulic oil discharged from the main pump 14 (see FIG. 3), respectively.

The cabin 10 is an operation room in which an operator is seated and is mounted on the front left side of the upper turning body 3.

The excavator 100 may have a configuration in which some of the driven elements such as the lower traveling body 1, the upper turning body 3, the boom 4, the arm 5, and the bucket 6 are electrically driven. That is, the excavator 100 may be a hybrid excavator or an electric excavator in which some of the driven elements are driven by electric actuators.

[Configuration of Excavator]

Next, a specific configuration of the excavator 100 will be described with reference to FIG. 3 in addition to FIG. 2.

FIG. 3 is a block diagram illustrating an example of the hardware configuration of the excavator 100 and the remote control room RC according to the present embodiment.

In FIG. 3, the path through which mechanical power is transmitted is indicated by a double line, the path through which high-pressure hydraulic oil for driving the hydraulic actuator flows is indicated by a solid line, the path through which pilot pressure is transmitted is indicated by a dashed line, and the path through which electrical signals are transmitted is indicated by a dotted line.

The excavator 100 includes components such as a hydraulic drive system for hydraulically driving the driven element, an operation system for operating the driven element, a user interface system for exchanging information with the user, a communication system for communicating with the outside, and a control system for various control operations.

As illustrated in FIG. 3, the hydraulic drive system of the excavator 100 includes hydraulic actuators HA for hydraulically driving each of the driven elements such as the lower traveling body 1 (left and right crawlers), the upper turning body 3, the boom 4, the arm 5, and the bucket 6, as described above. The hydraulic drive system of the excavator 100 according to the present embodiment includes an engine 11, a regulator 13, a main pump 14, and a control valve part 17.

The hydraulic actuator HA includes a traveling hydraulic motor 1ML, 1MR, a turning hydraulic motor 2M, a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9.

In the excavator 100, part or all of the hydraulic actuator HA may be replaced with an electric actuator. That is, the excavator 100 may be a hybrid excavator or an electric excavator.

The engine 11 is a prime mover of the excavator 100 and a main power source in the hydraulic drive system. The engine 11 is, for example, a diesel engine using light oil as fuel. The engine 11 is mounted, for example, at the rear of the upper turning body 3. The engine 11 rotates at a predetermined target speed, for example, under direct or indirect control by the controller 30 to be described later, and drives the main pump 14 and the pilot pump 15.

In place of or in addition to the engine 11, another motor (for example, electric motor) or the like may be mounted on the excavator 100.

The regulator 13 controls (adjusts) the discharge amount of the main pump 14 under the control of the controller 30. For example, the regulator 13 adjusts the angle (hereinafter, “tilt angle”) of the swash plate of the main pump 14 in response to a control instruction from the controller 30.

The main pump 14 supplies hydraulic oil to the control valve part 17 through a high-pressure hydraulic line. The main pump 14 is mounted, for example, at the rear of the upper turning body 3 in the same manner as the engine 11. The main pump 14 is driven by the engine 11 as described above. The main pump 14 is, for example, a variable displacement hydraulic pump, and as described above, the stroke length of the piston is adjusted by adjusting the tilt angle of the swash plate by the regulator 13 under the control of the controller 30, and the discharge flow rate and discharge pressure are controlled.

The control valve part 17 drives the hydraulic actuators HA in accordance with the contents of the operator's operation of the operation device 26 or a remote control or an operation instruction corresponding to an automatic operation function. The control valve part 17 is mounted, for example, in the center of the upper turning body 3. The control valve part 17 is connected to the main pump 14 via a high-pressure hydraulic line as described above, and selectively supplies hydraulic oil supplied from the main pump 14 to the respective hydraulic actuators in accordance with the operator's operation or an operation instruction corresponding to an automatic operation function. The control valve part 17 includes direction selector valves 17A to 17F for controlling the flow rate and the direction of flow of the hydraulic oil supplied from the main pump 14 to the hydraulic actuators HA.

The direction selector valve 17A controls the flow rate and the direction of flow of the hydraulic oil supplied to the boom cylinder 7. Thus, the direction selector valve 17A can expand and contract the boom cylinder 7 at a variable speed. The direction selector valve 17A is, for example, a spool valve.

The direction selector valve 17B controls the flow rate and the flow direction of the hydraulic oil supplied to the arm cylinder 8. Thus, the direction selector valve 17B can extend and contract the arm cylinder 8 at a variable speed. The direction selector valve 17B is, for example, a spool valve.

The direction selector valve 17C controls the flow rate and flow direction of the hydraulic oil supplied to the bucket cylinder 9. Thus, the direction selector valve 17C can extend and contract the bucket cylinder 9 at a variable speed. The direction selector valve 17C is, for example, a spool valve.

The direction selector valve 17D controls the flow rate and flow direction of the hydraulic oil supplied to the traveling hydraulic motor 1ML. Thus, the direction selector valve 17D can rotate the traveling hydraulic motor 1ML in both directions at a variable speed. The direction selector valve 17D is, for example, a spool valve.

The direction selector valve 17E controls the flow rate and flow direction of the hydraulic oil supplied to the traveling hydraulic motor 1MR. Thus, the direction selector valve 17E can rotate the traveling hydraulic motor 1MR in both directions at a variable speed. The direction selector valve 17E is, for example, a spool valve.

The direction selector valve 17F controls the flow rate and flow direction of the hydraulic oil supplied to the turning hydraulic motor 2M. Thus, the direction selector valve 17F can rotate the turning hydraulic motor 2M in both directions at a variable speed. The direction selector valve 17F is, for example, a spool valve.

As illustrated in FIG. 3, the operating system of the excavator 100 includes a pilot pump 15, an operation device 26, an operation sensor 29, and a proportional valve 31.

The pilot pump 15 supplies pilot pressure to various hydraulic devices via the pilot line 25. The pilot pump 15 is mounted, for example, at the rear of the upper turning body 3 in the same manner as the engine 11. The pilot pump 15 is, for example, a fixed displacement hydraulic pump and is driven by the engine 11 as described above.

Note that the pilot pump 15 may be omitted. In this case, after the relatively high pressure hydraulic oil discharged from the main pump 14 is depressurized by a predetermined pressure reducing valve, the relatively low pressure hydraulic oil may be supplied to various hydraulic devices as the pilot pressure.

The operation device 26 is provided near the operation seat of the cabin 10 and is used for an operator to operate various driven elements. Specifically, the operation device 26 is used for an operator to operate a hydraulic actuator HA that drives each driven element, and as a result, the operator can operate the driven element to be driven by the hydraulic actuator HA. The operation device 26 includes a pedal device and a lever device for operating each driven element (hydraulic actuator HA).

The operation sensor 29 is configured to detect the operation contents of the operator using the operation device 26. In the present embodiment, the operation sensor 29 detects the operation direction and operation amount of the operation device 26 corresponding to each actuator, and outputs an electric signal (hereinafter also referred to as an operation signal) corresponding to the detected value to the controller 30. In the present embodiment, the controller 30 controls the opening area of the proportional valve 31 according to the output of the operation sensor 29. Then, the controller 30 supplies the hydraulic oil discharged from the pilot pump 15 to the pilot port of the corresponding control valve in the control valve part 17. The pressure (pilot pressure) of the hydraulic oil supplied to each of the pilot ports is, in principle, the pressure corresponding to the operation direction and operation amount of the operation device 26 corresponding to each of the hydraulic actuators. Thus, the operation device 26 is configured to supply the hydraulic oil discharged from the pilot pump 15 to the pilot port of the corresponding control valve in the control valve part 17. Thus, the hydraulic actuator HA can be driven.

Further, the direction selector valves 17A to 17F incorporated in the control valve part 17 for driving the hydraulic actuator HA may be an electromagnetic solenoid type. In this case, the operation signal output from the operation device 26 may be directly input to the control valve part 17 (that is, to the solenoid type direction selector valve).

The operation device 26 may be a hydraulic pilot type. Specifically, the operation device 26 utilizes hydraulic oil supplied from the pilot pump 15 through the pilot line, and outputs the pilot pressure corresponding to the operation content to the secondary pilot line. The secondary pilot line is connected to the control valve part 17. Thus, the pilot pressure corresponding to the operation content of the various driven elements (hydraulic actuators HA) in the operation device 26 can be input to the control valve part 17. Therefore, the control valve part 17 can drive the respective hydraulic actuators HA according to the operation content of the operation device 26 by the operator or the like. In this case, an operation state sensor capable of acquiring information on the operation state of the operation device 26 is provided, and the output of the operation state sensor is taken into the controller 30. Thus, the controller 30 can identify the operation state of the operation device 26. The operation state sensor is, for example, a pressure sensor for acquiring information on the pilot pressure (operation pressure) of the secondary pilot line of the operation device 26.

Further, as described above, a part of or the entirety of the hydraulic actuator HA may be replaced with an electric actuator. In this case, for example, the controller 30 may output an operation instruction corresponding to the operation content of the operation device 26 or the remote control content specified by the remote control signal, to the electric actuator or a driver or the like that drives the electric actuator. Further, the operation signal may be input from the operation device 26 to the electric actuator or a driver or the like so that the electric actuator can be operated by the operation device 26.

Further, the operation device 26 may be omitted when the excavator 100 is operated exclusively by remote control or exclusively by the fully automatic operation function.

The proportional valve 31 functions as a control valve for machine control, and is provided for each driven element (hydraulic actuator HA) to be operated by the operation device 26 and for each operation direction (for example, the upward and downward directions of the boom 4) of the driven element (hydraulic actuator HA). For example, two proportional valves 31 are provided for each double-acting hydraulic actuator HA for driving the lower traveling body 1, the upper turning body 3, the boom 4, the arm 5, the bucket 6, and the like. The proportional valve 31 is provided, for example, in a pilot line between the pilot pump 15 and the control valve part 17, and may be configured so that the flow path area thereof (that is, the cross-sectional area through which the hydraulic oil can flow) can be changed. As a result, the proportional valve 31 can output a predetermined pilot pressure to the secondary pilot line by utilizing the hydraulic oil of the pilot pump 15 supplied through the primary pilot line. Therefore, the proportional valve 31 can apply a predetermined pilot pressure corresponding to an operation instruction from the controller 30, to the control valve part 17. Therefore, for example, the controller 30 can directly supply the pilot pressure corresponding to the operation content (operation signal) of the operation device 26 from the proportional valve 31 to the control valve part 17 to implement the operation of the excavator 100 based on the operation of the operator.

Further, the controller 30 may control the proportional valve 31 to implement an automatic operation function of the excavator 100. Specifically, the controller 30 outputs an operation instruction corresponding to the automatic operation function from the proportional valve 31 to the proportional valve 31. Thus, the controller 30 can implement the operation of the excavator 100 based on the automatic operation function.

The controller 30 controls the proportional valve 31 to implement remote control of the excavator 100. Specifically, the controller 30 outputs, to the proportional valve 31 by the communication device T1, an operation instruction corresponding to the operation content specified by the operation signal received from the remote control room RC. Thus, the controller 30 causes the proportional valve 31 to supply the pilot pressure corresponding to the remote control content to the control valve part 17, thereby implementing an operation of the excavator 100 based on remote control by the operator.

When the operation device 26 is a hydraulic pilot type, a shuttle valve may be provided in the pilot line between the operation device 26, the proportional valve 31, and the control valve part 17. The shuttle valve has two inlet ports and one outlet port, and outputs, to the outlet port, hydraulic oil having a higher pilot pressure among the pilot pressures input to the two inlet ports. Similar to the proportional valve 31, the shuttle valve is provided for each driven element (hydraulic actuator HA) to be operated by the operation device 26 and for each operation direction of the driven element (hydraulic actuator HA). For example, two shuttle valves are provided for each double-acting hydraulic actuator HA for driving the lower traveling body 1, the upper turning body 3, the boom 4, the arm 5, the bucket 6, and the like. One of the two inlet ports of the shuttle valve is connected to the secondary pilot line of the operation device 26 (specifically, the above-described lever device and pedal device included in the operation device 26), and the other is connected to the secondary pilot line of the proportional valve 31. The outlet port of the shuttle valve is connected to the pilot port of the corresponding direction selector valve of the control valve part 17 through the pilot line. The corresponding direction selector valve is a direction selector valve that drives the hydraulic actuator HA to be operated by the above-described lever device or pedal device connected to one inlet port of the shuttle valve. Therefore, these shuttle valves can apply, to the pilot port of the corresponding direction selector valve, the higher one of the pilot pressure of the secondary pilot line of the operation device 26 and the pilot pressure of the secondary pilot line of the proportional valve 31. That is, the controller 30 can control the corresponding direction selector valve regardless of the operator's operation of the operation device 26, by outputting, from the proportional valve 31, a pilot pressure higher than the pilot pressure of the secondary side of the operation device 26. Therefore, the controller 30 can control the operation of the driven element (the lower traveling body 1, the upper turning body 3, the boom 4, the arm 5, the bucket 6) regardless of the operator's operation of the operation device 26, to implement an automatic operation function and a remote control function.

When the operation device 26 is a hydraulic pilot type, a pressure reducing valve may be provided in the pilot line between the operation device 26 and the shuttle valve, in addition to the shuttle valve. The pressure reducing valve operates according to a control signal input from the controller 30, for example, and is configured so that its flow path area can be changed. Thus, the controller 30 can forcibly reduce the pilot pressure output from the operation device 26 when the operation device 26 is operated by the operator. Therefore, even when the operation device 26 is operated, the controller 30 can forcibly reduce or stop the operation of the hydraulic actuator HA corresponding to the operation of the operation device 26. Also, the controller 30 can reduce the pilot pressure output from the operation device 26 by the pressure reducing valve even when the operation device 26 is operated, for example, to lower the pilot pressure to lower than that output from the proportional valve 31. Therefore, by controlling the proportional valve 31 and the pressure reducing valve, for example, the controller 30 can cause the desired pilot pressure to reliably act on the pilot port of the direction switching valve in the control valve part 17, regardless of the operation content of the operation device 26. Therefore, by controlling the pressure reducing valve in addition to the proportional valve 31, for example, the controller 30 can more appropriately implement the automatic operation function and the remote control function of the excavator 100.

As illustrated in FIG. 3, the user interface system of the excavator 100 includes an operation device 26, an operation sensor 29, an output device D1, and an input device D2.

The output device D1 outputs various kinds of information to the user of the excavator 100 (for example, an operator in the cabin 10), the person around the excavator 100 (e.g., a worker or a driver of a work vehicle), and so on.

For example, the output device D1 includes a lighting device and a display device that output various kinds of information in a visual manner. The lighting device is, for example, a warning lamp (indicator lamp). The display device is, for example, a liquid crystal display or an organic EL (electroluminescence) display. For example, the lighting device or the display device may be provided inside the cabin 10 and output various kinds of information visually to an operator or the like inside the cabin 10. The lighting device or the display device may be provided on the side surface or the like of the upper turning body 3 and output various kinds of information visually to a worker or the like around the excavator 100.

The output device D1 may include a sound output device for outputting various kinds of information by an auditory method. The sound output device includes, for example, a buzzer or a speaker. The sound output device may be provided in at least one of the inside or the outside of the cabin 10, for example, and output various kinds of information visually to an operator inside the cabin 10 or a person (a worker or the like) around the excavator 100.

The output device D1 may include a device for outputting various kinds of information by a tactile method such as vibration of the operation seat.

The input device D2 receives various inputs from a user (e.g., an operator) of the excavator 100, and signals corresponding to the received inputs are taken into the controller 30. For example, as illustrated in FIG. 2, the input device D2 is provided inside the cabin 10 and receives inputs from an operator or the like inside the cabin 10. The input device D2 may also be provided, for example, on the side of the upper turning body 3 and receive inputs from a worker or the like around the excavator 100.

For example, the input device D2 may include an operation input device that receives inputs by mechanical operation from a user. The operation input device may include a touch panel mounted on the display device, a touch pad installed around the display device, a button switch, a lever, a toggle, and a knob switch provided in the operation device 26 (lever device).

The input device D2 may also include a voice input device that receives voice input from a user. The voice input device may include, for example, a microphone.

The input device D2 may also include a gesture input device for receiving gesture input from the user. The gesture input device may include, for example, an imaging device for imaging a gesture performed by the user.

The input device D2 may also include a biometric input device for receiving biometric input from the user. The biometric input may include, for example, the input of biometric information such as a user's fingerprint or iris.

As illustrated in FIG. 3, the communication system of the excavator 100 according to the present embodiment includes a communication device T1.

The communication device T1 is connected to an external communication line NW and communicates with a device provided separately from the excavator 100. The device provided separately from the excavator 100 may include a device outside the excavator 100 and a portable terminal device (portable terminal) brought into the cabin 10 by the user of the excavator 100. The communication device T1 may include, for example, a mobile communication module conforming to standards such as 4G (4th Generation) or 5G (5th Generation). The communication device T1 may include, for example, a satellite communication module. The communication device T1 may include, for example, a Wi-Fi communication module or a Bluetooth (registered trademark) communication module. The communication device T1 may also include a plurality of communication devices T1 according to the type of communication line NW when there are a plurality of communication lines NW that can be connected.

For example, the communication device T1 communicates with an external device such as a remote control room RC in the work site through a local communication line constructed at the work site. The local communication line may be, for example, a mobile communication line using local 5G constructed at the work site or a local network using WiFi6.

The communication device T1 is configured to transmit and receive information to and from the communication device T2 installed in the remote control room RC through a wide area communication line including the work site, that is, a wide area network.

As illustrated in FIG. 3, the control system of the excavator 100 includes a controller 30. The controller 30 performs various controls related to the excavator 100.

The functions of the controller 30 may be implemented by any hardware or any combination of hardware and software. For example, as illustrated in FIG. 3, the controller 30 includes an auxiliary storage device 30A, a memory device 30B, a CPU (Central Processing Unit) 30C, and an interface device 30D connected by a bus B1.

The auxiliary storage device 30A is a nonvolatile storage means and stores programs to be installed, and also stores necessary files, data, and the like. The auxiliary storage device 30A is, for example, an EEPROM (Electrically Erasable Programmable Read-Only Memory) or a flash memory.

The memory device 30B loads the program of the auxiliary storage device 30A so that the CPU 30C can read it when a program start instruction is given, for example. The memory device 30B is, for example, an SRAM (Static Random Access Memory).

The CPU 30C executes the program loaded into the memory device 30B, for example, and implements various functions of the controller 30 according to the instruction of the program.

The interface device 30D functions, for example, as a communication interface for connecting to the communication line inside the excavator 100. The interface device 30D may include a plurality of different types of communication interfaces according to the type of communication line to be connected.

The interface device 30D also functions as an external interface for reading data from or writing data to a recording medium. The recording medium is, for example, an exclusive-use tool connected, by a detachable cable, to a connector installed inside the cabin 10. The recording medium may be, for example, a general-purpose recording medium such as an SD memory card or a USB (Universal Serial Bus) memory. Thus, a program for implementing various functions of the controller 30 may be provided, for example, by a portable recording medium and installed in the auxiliary storage device 30A of the controller 30. The program may be downloaded from another computer outside the excavator 100 through the communication device T1 and installed in the auxiliary storage device 30A.

Note that a part of the functions of the controller 30 may be implemented by other controllers (control devices). That is, the functions of the controller 30 may be implemented in a distributed manner by a plurality of controllers installed in the excavator 100.

The boom angle sensor S1 is attached to the boom 4 and detects the rising angle (hereinafter, “boom angle”) of the boom 4 with respect to the upper turning body 3, for example, the angle formed by a straight line connecting the fulcrums of both ends of the boom 4 with respect to the turning plane of the upper turning body 3 in side view. The boom angle sensor S1 may include, for example, a rotary encoder, an acceleration sensor, a 6-axis sensor, an Inertial Measurement Unit (IMU), and the like. The boom angle sensor S1 may also include a potentiometer using a variable resistor, a cylinder stroke sensor for detecting the stroke amount of a hydraulic cylinder (boom cylinder 7) corresponding to the boom angle, and the like. Hereinafter, the same applies to the arm angle sensor S2, the bucket angle sensor S3, and the body inclination sensor S4. The detection signal corresponding to the boom angle by the boom angle sensor S1 is taken into the controller 30.

The arm angle sensor S2 is attached to the arm 5 and detects the rotation angle (hereinafter, ‘arm angle’) of the arm 5 with respect to the boom 4, for example, the angle formed by a straight line connecting the fulcrums of both ends of the arm 5 with respect to a straight line connecting the fulcrums of both ends of the boom 4 in side view. The detection signal corresponding to the arm angle by the arm angle sensor S2 is taken into the controller 30.

The bucket angle sensor S3 is attached to the bucket 6 and detects the rotation angle (hereinafter, “bucket angle”) of the bucket 6 with respect to the arm 5, for example, the angle formed by a straight line connecting the fulcrum and the tip (cutting edge) of the bucket 6 with respect to a straight line connecting the fulcrums of both ends of the arm 5 in a side view. The detection signal corresponding to the bucket angle detected by the bucket angle sensor S3 is taken into the controller 30.

In the present embodiment, the boom angle sensor S1, the arm angle sensor S2, and the bucket angle sensor S3 are also referred to as angle sensors of the attachment AT. The detection result by the angle sensor of the attachment AT is also referred to as the angle of the attachment AT. The angle of the attachment AT indicates, for example, the boom angle, the arm angle, and the bucket angle.

The body inclination sensor S4 detects the inclined state of the body (the upper turning body 3 or the lower traveling body 1) with respect to the horizontal plane. The body inclination sensor S4 is attached to the upper turning body 3, for example, and detects the inclination angles (hereinafter, “longitudinal inclination angle” and “lateral inclination angle”) around two axes in the longitudinal and lateral directions of the excavator 100 (that is, the upper turning body 3). The detection signals corresponding to the inclination angles (the longitudinal and lateral inclination angles) detected by the body inclination sensor S4 are taken into the controller 30.

The turning angle sensor S5 outputs detection information related to the turning state of the upper turning body 3. The turning angle sensor S5 detects, for example, the turning angle speed and the turning angle of the upper turning body 3. The turning angle sensor S5 includes, for example, a gyro sensor, a resolver, a rotary encoder, and the like.

Although the present embodiment describes an example using the turning angle sensor S5, the present embodiment is not limited to a method using the turning angle sensor S5. For example, an IMU (Inertial Measurement Unit) sensor may be used instead of the turning angle sensor S5.

For example, the controller 30 can identify (estimate) the position of the tip (bucket 6) of the attachment AT based on the outputs of the sensors S1 to S5. Therefore, the controller 30 can control the operation by the automatic operation function of the excavator 100 while identifying the position of the tip of the attachment AT.

When the sensor S4 includes a gyro sensor, a 6-axis sensor, an IMU or the like capable of detecting the angular velocity around the 3-axis, the turning state (for example, turning angular velocity) of the upper turning body 3 may be detected based on the detection signal of the sensor S4. In this case, the sensor S5 may be omitted.

The imaging device S6 captures the surroundings of the excavator 100. The imaging device S6 includes a camera S6F for capturing the area in front of the excavator 100, a camera S6L for capturing the area on the left of the excavator 100, a camera S6R for capturing the area on the right of the excavator 100, and a camera S6B for capturing an area behind the excavator 100.

The camera S6F is attached, for example, to the ceiling of the cabin 10, that is, to the inside of the cabin 10. The camera S6F may also be attached to the outside of the cabin 10, such as the roof of the cabin 10 or the side face of the boom 4. The camera S6L is attached to the left end of the upper surface of the upper turning body 3, the camera S6R is attached to the right end of the upper surface of the upper turning body 3, and the camera S6B is attached to the rear end of the upper surface of the upper turning body 3.

Each of the imaging devices S6 (cameras S6F, S6B, S6L, S6R) is, for example, a monocular wide-angle camera having a very wide angle of view. The imaging device S6 may be capable of acquiring data related to distance (depth) in addition to a two-dimensional image, such as a stereo camera, a TOF (Time of Flight) camera, etc. (hereinafter, comprehensively described as “3D camera”). The captured image obtained by the imaging device S6 is taken into the controller 30.

When the operator OP of the remote control room RC receives the captured image from the communication device T1 of the excavator 100, the operator OP of the remote control room RC can remotely operate the excavator 100 while confirming the operation of the attachment AT including the bucket 6 by visually confirming the surrounding image based on the camera S6F through the display device DR.

Further, a distance sensor may be provided in the upper turning body 3, in place of or in addition to the imaging device S6. The distance sensor is attached to the upper part of the upper turning body 3, for example, and acquires data related to the distance and direction of an object around the excavator 100 as a reference. The distance sensor may also acquire (generate) three-dimensional data (for example, coordinate information data that is a group of dots) of an object around the excavator 100 within the sensing range based on the acquired data. The distance sensor may be, for example, LiDAR (Light Detection and Ranging). The distance sensor may be, for example, a millimeter-wave radar, an ultrasonic sensor, or an infrared sensor.

The positioning device PS is configured to acquire information about the position of the excavator 100. In the present embodiment, the positioning device PS is configured to measure the position and orientation of the excavator 100. For example, the positioning device PS is a GNSS (Global Navigation Satellite System) receiver incorporating an electronic compass, and measures the latitude, longitude, and altitude of the current position of the excavator 100, and measures the orientation of the excavator 100.

The excavator 100 operates actuators (for example, hydraulic actuators) in response to the operation of an operator seated in the cabin 10, and drives operating elements (hereinafter, “driven elements”) such as the lower traveling body 1, the upper turning body 3, the boom 4, the arm 5, and the bucket 6.

Instead of or in addition to being operable by an operator of the cabin 10, the excavator 100 may be configured to be remotely operated from the outside of the excavator 100. When the excavator 100 is remotely operated, the interior of the cabin 10 may be unmanned.

The excavator 100 may automatically operate the actuators regardless of the operation of the operator. Thereby, the excavator 100 implements the function of automatically operating at least a part of the driven elements such as the lower traveling body 1, the upper turning body 3, the boom 4, the arm 5, and the bucket 6, that is, what is referred to as the “automatic driving function” or the “machine control function”.

The automatic operation function may include a function for automatically operating a driven element (actuator) other than the driven element (actuator) to be operated in response to an operator's operation or remote control of the operation device 26, that is, what is referred to as a “semi-automatic operation function” or an “operation support type machine control function”. The automatic operation function may also include a function for automatically operating at least a part of the plurality of driven elements (hydraulic actuators) on the assumption that there is no operator's operation of the operation device 26 or remote control, that is, what is referred to as a “fully automatic operation function” or a “fully automatic type machine control function”. When the fully automatic operation function is enabled in the excavator 100, the interior of the cabin 10 may be in an unmanned state. Further, the semi-automatic operation function, the fully automatic operation function, and the like may include a mode in which the operation content of the driven element (actuator) to be operated automatically in accordance with a predetermined rule is automatically determined. Further, the semi-automatic operation function, the fully automatic operation function, and the like may include a mode in which the excavator 100 autonomously makes various determinations and autonomously determines the operation content of the driven element (hydraulic actuator) to be operated automatically in accordance with the determination result (what is referred to as a “automatic operation function”).

Specifically, when the operator operates the arm 5 through the operation device 26, the controller 30 may automatically operate at least one of the boom 4 or the bucket 6 so that the predetermined target design surface (hereinafter, simply “design surface”) coincides with the tip position of the bucket 6. Also, the controller 30 may automatically operate the arm 5 regardless of the operating state of the operation device 26 operating the arm 5. That is, the controller 30 may make the attachment perform a predetermined operation by using the operation of the operation device 26 by the operator as a trigger.

Hereinafter, the function of the controller 30 to operate not only the arm 5 but also at least one of the boom 4 or the bucket 6 in response to the operation of the operation device 26 corresponding to the arm 5 is referred to as a “semi-automatic operation function”. The semi-automatic operation function may be executed, for example, by operating a predetermined switch (hereinafter, the “MC (Machine Control) Switch”) arranged at the tip of any of the lever devices included in the operation device 26.

FIG. 4 is a functional block diagram illustrating a configuration example of the remote control system SYS according to the present embodiment. In the example illustrated in FIG. 4, each block configuration of the remote control room RC and the excavator 100 included in the remote control system SYS is illustrated.

As illustrated in FIG. 4, the remote control room RC includes an operation sensor R29, a remote controller R30, a display device DR, and a communication device T2.

The display device DR according to the present embodiment may be a multi-display device composed of a plurality of monitors or may be composed of one large-screen monitor.

The communication device T2 is connected to an external communication line NW and communicates with the excavator 100. The communication device T2 may include, for example, a mobile communication module conforming to standards such as 4G (4th Generation) or 5G (5th Generation). The communication device T2 may include, for example, a satellite communication module. The communication device T2 may include, for example, a Wi-Fi communication module or a Bluetooth (registered trademark) communication module. The communication device T2 may also include a plurality of communication devices T2 according to the type of communication line NW when there are a plurality of communication lines NW that can be connected.

The operation sensor R29 is configured to detect the operation contents of the operator OP using the operation device R26. In the present embodiment, the operation sensor 29 detects the operation direction and the operation amount of the operation device 26 corresponding to each actuator of the excavator 100, and outputs an electric signal (hereinafter also referred to as an operation signal) corresponding to the detected value to the remote controller R30.

Next, the functions of the remote controller R30 installed in the remote control room RC will be described. The remote controller R30 is configured to remotely operate the excavator 100. The remote controller R30 has a display control part 351, an operation signal generating part 352, and a communication control part 353 as functional blocks.

The communication control part 353 controls the transmission and reception of information to and from the communication device T1 of the excavator 100, by using the communication device T2. For example, the communication control part 353 receives, from the communication device T1 of the excavator 100, the detection results of the various sensors S1 to S5 of the excavator 100, the position information obtained by the positioning device PS, and the captured image obtained by the imaging device S6.

The display control part 351 controls the display of information on the display device DR. For example, the display control part 351 controls the display device DR to display the received imaging information. Further, the display control part 351 may control the display device DR to display information based on the detection results obtained by various sensors S1 to S5 or the position information obtained by the positioning device PS.

The operation signal generating part 352 is configured to generate an operation signal. In the present embodiment, the operation signal generating part 352 is configured to generate an operation signal based on the output of the operation sensor R29.

The communication control part 353 transmits the generated operation signal to the communication device T1.

As illustrated in FIG. 4, the excavator 100 includes a positioning device PS, an imaging device S6, a turning angle sensor S5, a body inclination sensor S4, an operation sensor 29, a proportional valve 31, a controller 30, and a communication device T1.

The controller 30 stores a map information storage part 30A1 in the auxiliary storage device 30A.

The map information storage part 30A1 stores map information for the excavator 100 to travel. The map information stores the shape (three-dimensional shape) of the work site where the excavator 100 can move. The map information has a three-dimensional shape and includes, for example, an inclination angle.

The map information may be, for example, position information in the global coordinate system based on the Global Navigation Satellite System (GNSS). In the present embodiment, latitude and longitude are indicated on the x-axis and y-axis, respectively, and altitude is indicated on the z-axis.

The functions of the controller 30 mounted on the excavator 100 will be described below. As illustrated in FIG. 5, the controller 30 includes, as functional blocks, a communication control part 301, an acquiring part 302, an inclination angle calculating part 303, a target traveling direction identifying part 304, a determining part 305, a correcting part 306, and an actuator driving part 307.

FIG. 5 is an explanatory diagram illustrating control of the lower traveling body 1 of the excavator 100 by the controller 30 according to the present embodiment. FIG. 5 illustrates an example in which a conventional excavator 100A and the excavator 100 according to the present embodiment are traveling down a slope 500 having an inclination angle θ. Conventionally, when an excavator travels on a slope, it is preferable to travel straight with respect to the inclined direction.

Therefore, the conventional excavator 100A is an example in which it is traveling straight with respect to the inclined direction as illustrated by the traveling trajectories 513 and 514. Similarly, the excavator 100 according to the present embodiment is also an example in which it is traveling straight with respect to the inclined direction as illustrated by the traveling trajectories 511 and 512.

In the example illustrated in FIG. 5, a slippery ground such as mud 501 exists on the slope 500. A situation occurs in which both the excavators 100A and 100 move on the mud 501.

In the conventional excavator 100A, when the crawler slips on the mud 501, a sudden change of direction may occur. The sudden change of direction may deviate from the intended travel path of the conventional excavator 100A and cause the excavator 100A to overturn.

Therefore, the controller 30 of the excavator 100 according to the present embodiment controls the lower traveling body 1 so that a sudden change of direction does not occur even if the crawler slips on the mud 501; that is, the traveling direction is maintained substantially parallel to the inclined direction.

In particular, in the remote control system SYS of the excavator 100 according to the present embodiment, when the operator OP operates the excavator 100 from the remote control room RC, it is difficult to recognize the inclination of the road surface on which the excavator 100 is traveling. Further, there is a delay until the detection results of various sensors of the excavator 100 are displayed on the display device DR. Therefore, when the controller 30 controls the lower traveling body 1 as described above, the possibility of overturning the excavator 100 can be reduced.

Referring back to FIG. 4, the communication control part 301 controls the transmission and reception of information to and from the communication device T2 in the remote control room RC, by using the communication device T1. For example, the communication control part 301 receives an operation signal from the communication device T2 in the remote control room RC.

The acquiring part 302 acquires detection results from various sensors provided in the excavator 100. For example, the acquiring part 302 acquires information from the boom angle sensor S1, the arm angle sensor S2, the bucket angle sensor S3, the body inclination sensor S4, the turning angle sensor S5, the imaging device S6, the positioning device PS, and the like.

The communication control part 301 uses the communication device T1 to transmit the detection results of the various sensors S1 to S5 of the excavator 100, the position information obtained by the positioning device PS, and the captured image obtained by the imaging device S6, to the communication device T2.

The inclination angle calculating part 303 calculates the inclination of the traveling direction of the excavator 100 with respect to the inclined direction of the ground based on the inclination state of the upper turning body 3 detected by the body inclination sensor S4 and the turning angle detected by the turning angle sensor S5.

Specifically, the acquiring part 302 acquires the pitch angle and roll angle of the upper turning body 3 as the inclined state of the upper turning body 3 detected by the body inclination sensor S4, and acquires the turning angle from the turning angle sensor S5. The inclination angle calculating part 303 calculates the pitch angle and roll angle of the lower traveling body 1 from the pitch angle and roll angle and the turning angle of the upper turning body 3.

In the present embodiment, it is assumed that the roll angle of the lower traveling body 1 corresponds to the inclination of the traveling direction of the excavator 100 with respect to the inclined direction of the ground. For example, when the roll angle of the lower traveling body 1 is approximately 0 degrees, the controller 30 can recognize that the traveling direction of the excavator 100 with respect to the inclined direction is approximately parallel, that is, no inclination occurs in the traveling direction with respect to the inclined direction. When the absolute value of the roll angle increases from approximately 0 degrees, the controller 30 can recognize that an inclination has occurred in the traveling direction with respect to the inclined direction. Note that the present embodiment is not limited to the method of recognizing the inclination of the traveling direction of the excavator 100 with respect to the roll angle of the lower traveling body 1, and other methods may be used.

The inclination angle calculating part 303 calculates the inclination angle of the ground on which the lower traveling body 1 is traveling based on the pitch angle and the roll angle of the lower traveling body 1. As for the method for calculating the inclination angle of the ground, a known method may be used, and description thereof is omitted.

Therefore, the configuration in which the body inclination sensor S4 and the turning angle sensor S5 are combined functions as an inclination recognition device for recognizing the inclination of the ground on which the excavator 100 is traveling, and can calculate the inclination of the traveling direction with respect to the inclined direction. In the present embodiment, by using the configuration in which the body inclination sensor S4 and the turning angle sensor S5 are combined, the controller 30 can immediately recognize a change in the pitch angle or roll angle of the lower traveling body 1. Therefore, because the controller 30 can immediately perform control based on the change, safety can be improved.

In the present embodiment, an example of using the body inclination sensor S4 as the configuration for detecting the pitch angle and roll angle of the upper turning body 3 is described, but the method of using the body inclination sensor S4 as the configuration for detecting the pitch angle and roll angle of the upper turning body 3 is not limited. For example, a positioning device PS configured as a GNSS receiver capable of detecting the inclination of the excavator 100 may be used.

When the inclination of the ground is recognized based on the captured image obtained by the imaging device S6, the target traveling direction identifying part 304 identifies the traveling direction (hereinafter, the target traveling direction) that is the target of the excavator 100.

That is, in this example, the imaging device S6 is used as an inclination recognition device for recognizing the inclination of the ground. In the present embodiment, an example using the imaging device S6 will be described, but the method is not limited to the method using the imaging device S6. That is, any space recognition device capable of recognizing the space of the excavator 100 may be used, for example, LiDAR or the like.

Specifically, the target traveling direction identifying part 304 identifies an area around the excavator 100 where the inclination angle of the ground is switched (changes) from the captured image obtained by the imaging device S6, and identifies a target traveling direction to be substantially parallel to the inclined direction in the identified area.

The method by which the target traveling direction identifying part 304 recognizes the inclination of the ground appearing in the image information, from the image information, will be omitted as a known method is used.

The controller 30 according to the present embodiment can recognize in advance the inclination of the destination of the excavator 100 by using the imaging device S6. Specifically, the controller 30 can recognize the inclination angle of the inclined ground (hereinafter, also referred to as an inclined plane) that exists at the destination of the excavator before the excavator starts traveling on the inclined ground, while the excavator is traveling on a horizontal plane or a plane whose inclination angle is more gentle than the inclined plane. In this way, the controller 30 can recognize the inclination angle of the inclined surface even before the inclination angle of the inclined surface is recognized by the body inclination sensor S4. That is, the controller 30 can identify the traveling direction on the inclined surface before the excavator 100 advances to the inclined surface. Because the controller 30 can easily cope with the change of the inclined surface, safety can be improved.

Specifically, the target traveling direction identifying part 304 calculates the difference in the relative inclination angle, between the current ground and the ground after the inclination angle is switched from the current ground, based on the captured image. Because the controller 30 of the excavator 100 recognizes the current inclination state of the ground, it recognizes the inclination state of the ground after the inclination angle is switched, from the difference in the relative inclination angle. Then, based on the inclination state, the controller 30 can identify the target traveling direction for traveling straight with respect to the inclined direction on the ground after the inclination angle is switched.

In the present embodiment, the method for calculating the difference of the relative inclination angle is not limited to the calculation based on the captured image. For example, the target traveling direction identifying part 304 may identify the inclination angle of the ground with respect to which the excavator 100 is moved, from the map information stored in the map information storage part 30A1 and the position information of the excavator 100.

The determining part 305 determines whether or not the conditions for controlling the lower traveling body 1 are satisfied. For example, the determining part 305 determines whether or not the inclination angle of the ground calculated by the inclination angle calculating part 303 is greater than or equal to a first reference angle (an example of a predetermined threshold). The first reference angle may be determined to be, for example, 20 degrees. Note that the first reference angle is not limited to 20 degrees, but may be determined to be an angle at which the excavator 100 may overturn, etc., and may be determined in accordance with embodiments such as the speed and shape of the excavator 100.

If the inclination angle of the ground calculated by the inclination angle calculating part 303 is determined to be greater than or equal to the first reference angle, the determining part 305 further determines whether or not the roll angle is greater than or equal to a predetermined reference roll angle. The predetermined reference roll angle according to the present embodiment is an angle determined as a reference for determining that the traveling direction is not substantially parallel to the inclined direction. For example, the predetermined reference roll angle is determined as an angle obtained by adding a predetermined margin to the roll angle of “0” degrees.

The correcting part 306 corrects the operation signal received by the communication control part 301 or the operation signal acquired by the acquiring part 302, based on the determination result of the determining part 305.

When the determining part 305 determines that the inclination angle of the ground calculated by the inclination angle calculating part 303 is greater than or equal to the first reference angle (one example of a predetermined threshold), the correcting part 306 corrects the operation signal in order to cause the lower traveling body 1 to perform control to make the traveling direction of the excavator 100 and the inclined direction substantially parallel. The present embodiment describes an example of performing control to make the traveling direction of the excavator 100 and the inclined direction substantially parallel, but it is not limited to control to make the traveling direction and the inclined direction substantially parallel. The correcting part 306 may perform control so that the angle between the traveling direction of the excavator 100 and the inclined direction becomes small. The angle between the traveling direction and the inclined direction after the control may be a predetermined angle at which the overturn of the excavator 100 can be prevented. That is, even when the correcting part 306 corrects the operation signal so that the angle between the traveling direction of the excavator 100 and the inclined direction becomes small, the possibility of the excavator 100 overturning or the like can be reduced, thereby improving safety.

Specifically, when the determining part 305 determines that the inclination angle of the ground is greater than or equal to the first reference angle (one example of a predetermined threshold) and that the roll angle of the lower traveling body 1 is greater than or equal to the predetermined reference roll angle, the correcting part 306 adjusts the traveling speed of either one or more of the right crawler and the left crawler to correct the operation signal so that the roll angle becomes approximately 0 degrees. When the roll angle of the lower traveling body 1 becomes approximately 0 degrees, the lateral inclination of the excavator 100 is reduced, and, therefore, it can be considered that the traveling direction of the excavator 100 and the inclined direction has become approximately parallel.

When the excavator 100 is tilted in the lateral direction while the excavator 100 is traveling on an inclined surface, the correcting part 306 corrects the operation signal to adjust the traveling speed of the right crawler and the traveling speed of the left crawler so as to reduce the lateral tilt of the excavator 100.

For example, when the lower traveling body 1 is shifted to the right, the correcting part 306 corrects the operation signal to reduce the operation amount of the left operation lever controlling the traveling speed of the left crawler so as to reduce the traveling speed of the left crawler. When the lower traveling body 1 is shifted to the right, the correcting part 306 may correct the operation signal to increase the operation amount of the right operation lever so as to increase the traveling speed of the right crawler.

As another example, when the lower traveling body 1 is shifted to the left, the correcting part 306 corrects the operation signal to decrease the operation amount of the right operation lever controlling the traveling speed of the right crawler so as to reduce the traveling speed of the right crawler. When the lower traveling body 1 is shifted to the left, the correcting part 306 may correct the operation signal to increase the operation amount of the left operation lever so as to increase the traveling speed of the left crawler.

Further, when the determining part 305 determines that the inclination angle of the ground calculated by the inclination angle calculating part 303 is smaller than the first reference angle (an example of a predetermined threshold value), the correcting part 306 prevents the correction of the operation signal for making the traveling direction of the excavator 100 substantially parallel to the inclined direction, to prevent the above-described control of the lower traveling body 1. In this way, when the inclination of the ground is gentle or substantially horizontal, it is assumed that the excavator 100 will not overturn, and correction of the operation signal is prevented. Therefore, when the inclination of the ground is gentle, the controller 30 prevents the correction of the operation signal, and the excavator 100 can move according to the operation by the operator OP. Therefore, both improvement of safety and operability of the excavator 100 can be implemented.

When the inclination angle of the ground is determined to be greater than or equal to the first reference angle (one example of a predetermined threshold value) and the roll angle of the lower traveling body 1 is determined to be greater than or equal to the predetermined reference roll angle, the communication control part 301 transmits, via the communication device T1, a signal indicating a warning to the remote control room RC that the traveling direction of the excavator 100 will be corrected according to the inclined direction. Then, the remote controller R30 of the remote control room RC outputs a warning to the operator OP that the traveling direction will be corrected according to the received signal. The warning may be voice or display on the display device DR. Thus, the operator OP can recognize that the traveling direction will be corrected according to the inclined plane.

In the present embodiment, the case where the correcting part 306 automatically corrects the operation signal according to the determination result of the determining part 305 has been described. However, the present embodiment is not limited to the method of automatically correcting the operation signal, and the operation signal may be corrected according to a determination result of the operator OP.

For example, when the determining part 305 determines that the inclination angle of the ground is greater than or equal to the first reference angle (an example of a predetermined threshold) and that the roll angle of the lower traveling body 1 is greater than or equal to the predetermined reference roll angle, the communication control part 301 transmits a signal to the remote control room RC requesting permission for correction.

When the remote controller R30 of the remote control room RC receives the signal, the remote controller R30 outputs, by voice or to the screen, an inquiry as to whether the traveling direction may be changed according to the inclination angle of the ground. When the remote controller R30 receives, from the operator OP, an operation indicating that the operation direction may be changed via the operation sensor R29, the remote controller R30 transmits, to the excavator 100, a signal indicating that correction is permitted. Then, the correcting part 306 corrects the operation signal according to the received signal.

The actuator driving part 307 is configured to drive an actuator mounted on the excavator 100. In the present embodiment, the actuator driving part 307 generates and outputs an actuation signal for each of the plurality of solenoid valves included in the proportional valve 31 based on the operation signal transmitted from the remote controller R30.

When the operation signal is corrected by the correcting part 306, the actuator driving part 307 generates and outputs an actuation signal for controlling the lower traveling body 1 from the corrected operation signal.

Next, the processing procedure executed by the controller 30 according to the present embodiment will be described. FIG. 6 is a flowchart illustrating the processing procedure for the controller 30 according to the present embodiment to cause the excavator 100 to travel on the inclined ground.

First, the communication control part 301 receives an operation signal from the remote control room RC (S1601). The present embodiment is not limited to the mode of receiving the operation signal from the remote control room RC, and for example, the acquiring part 302 may acquire the operation signal based on the operation amount detected by the operation sensor 29.

The inclination angle calculating part 303 calculates the roll angle and the pitch angle of the lower traveling body 1 as the inclined state of the lower traveling body 1 (S1602).

Further, the inclination angle calculating part 303 calculates the inclination angle of the ground on which the excavator 100 is traveling based on the roll angle and the pitch angle of the lower traveling body 1 (S1603).

The determining part 305 determines whether the calculated inclination angle is greater than or equal to the first reference angle (one example of a predetermined threshold) (S1604). If it is determined that the calculated inclination angle is smaller than the first reference angle (S1604: NO), the controller 30 ends the process on the assumption that the ground is not inclined and that regular control is sufficient.

On the other hand, if it is determined that the calculated inclination angle is greater than or equal to the first reference angle (one example of a predetermined threshold) (S1604: YES), the determining part 305 determines whether the traveling direction of the excavator 100 is inclined with respect to the inclined direction based on the roll angle (S1605). If it is determined that the traveling direction is not inclined (S1605: NO), the process proceeds to S1608.

On the other hand, if the determining part 305 determines that the traveling direction of the excavator 100 is inclined with respect to the inclined direction (S1605: YES), the communication control part 301 transmits a signal indicating a warning to correct the traveling direction to the remote control room RC via the communication device T1 (S1606).

Thereafter, the correcting part 306 corrects the operation signal so that the lower traveling body 1 performs control to make the traveling direction of the excavator 100 and the inclined direction substantially parallel (S1607). In the flowchart illustrated in FIG. 6, an example of automatically correcting the operation signal will be described. However, as described above, it is possible to switch whether or not to correct the operation signal according to the operation of the operator OP in the remote control room RC.

Then, the actuator driving part 307 generates and outputs an actuation signal for controlling the lower traveling body 1, from the operation signal (S1608).

Then, the communication control part 301 receives the operation signal from the remote control room RC (S1609).

The inclination angle calculating part 303 calculates the roll angle and pitch angle of the lower traveling body 1 as the inclination state of the lower traveling body 1 (S1610).

Further, the inclination angle calculating part 303 calculates the inclination angle of the ground on which the excavator 100 is traveling based on the roll angle and pitch angle of the lower traveling body 1 (S1611).

The determining part 305 determines whether the calculated inclination angle is less than or equal to the second reference angle (S1612). If it is determined that the inclination angle is not less than or equal to the second reference angle, that is, the inclination angle is greater than to the second reference angle (S1612: NO), the process starts again from S1605. The second reference angle is an angle smaller than the first reference angle, and is 10 degrees, for example.

On the other hand, if the determining part 305 determines that the calculated inclination angle is less than or equal to the second reference angle (S1612: NO), the process ends.

The present embodiment has described an example of controlling the lower traveling body 1 to make the traveling direction of the excavator 100 substantially parallel to the inclined direction when it is determined that the traveling direction is inclined, but the control method is not limited thereto. For example, the controller 30 may perform control to correct the operation signal on condition that the angle of the traveling direction of the excavator 100 with respect to the inclined direction exceeds a predetermined angle.

FIG. 7 is an explanatory diagram illustrating the traveling trajectory of the crawler when the controller 30 according to the present embodiment controls the lower traveling body 1. In the example illustrated in FIG. 7, it is assumed that the excavator 100 is traveling in a straight direction with respect to the inclined surface 1700, as illustrated by the traveling trajectories 1701 and 1702.

Then, it is assumed that the left crawler of the excavator 100 slips at the point 1703 and the excavator 100 shifts to the right. When the control illustrated in FIG. 6 is not performed, the excavator travels as illustrated by the traveling trajectories 1711 and 1712.

On the other hand, the controller 30 according to the present embodiment performs the control illustrated in FIG. 6. Specifically, when it is recognized that the traveling direction is inclined with respect to the inclined direction while the excavator 100 travels on the ground, the controller 30 corrects the operation signal so that the traveling direction is substantially parallel to the inclined direction (so as to reduce the inclination). Therefore, because the excavator 100 can continue traveling as illustrated by the traveling trajectories 1701 and 1702, the safety can be improved.

The present embodiment is not limited to the method of correcting the operation signal when it is recognized that the current traveling direction is inclined with respect to the inclined direction. When it is recognized that the traveling direction will be inclined with respect to the inclined direction while traveling on a substantially horizontal plane, the operation signal may be corrected in advance.

Next, the processing procedure executed by the controller 30 according to the present embodiment will be described. FIG. 8 is a flowchart illustrating the processing procedure for the controller 30 according to the present embodiment to allow the excavator 100 to travel before the inclination of the ground is switched. First, it is assumed that the excavator 100 is traveling on the ground that is a substantially horizontal plane.

First, the communication control part 301 receives an operation signal from the remote control room RC (S1801). The present embodiment is not limited to the mode of receiving the operation signal from the remote control room RC, but for example, the acquiring part 302 may acquire an operation signal based on the amount of operation detected by the operation sensor 29.

The target traveling direction identifying part 304 determines whether or not there exists an area where the inclination angle of the ground is switched in the ground shape around the excavator 100 from the captured image by the imaging device S6 (S1802). If it is determined that there is no area in which the inclination angle of the ground is switched (to greater than or equal to the first reference angle) (S1802: NO), the controller 30 ends the process upon assuming that it is sufficient to perform the regular control because the ground is not inclined.

On the other hand, if it is determined that there is an area in which the inclination angle of the ground is switched, the target traveling direction identifying part 304 identifies the target yaw angle of the excavator 100, which is the target traveling direction to be substantially parallel to the inclined direction on the ground after the inclination angle is switched, based on the captured image obtained by the imaging device S6 (S1803). The target yaw angle is the rotation angle of the lower traveling body 1 for travelling substantially parallel to the inclined direction.

Then, based on the captured image obtained by the imaging device S6, the determining part 305 determines that the excavator 100 has reached a predetermined distance (for example, 1 m) before the area in which the inclination angle is switched (S1804). Although the present embodiment describes an example in which the operation signal is corrected 1 m before the inclination angle is switched, it is not limited to 1 m before the inclination angle is switched. The distance may be shorter than 1 m or longer than 1 m. Further, the operation signal may be corrected at a stage in which it is recognized that an area in which the inclination angle of the ground is switched exists.

Then, the determining part 305 determines whether or not the current traveling direction of the excavator 100 is inclined with respect to the target traveling direction identified in S1803, that is, whether or not the target yaw angle of the excavator 100 is different from “0” degrees (S1805). If it is determined that the current traveling direction is not inclined with respect to the target traveling direction, that is, that the target yaw angle is substantially equal to “0” degrees (S1805: NO), the process proceeds to S1808. Note that the present embodiment is not limited to a method of making the traveling direction coincide with the target yaw angle, and may be controlled so that the traveling direction is within a predetermined range (for example, ±5 degrees) based on the target yaw angle.

On the other hand, if the determining part 305 determines that the current traveling direction of the excavator 100 is inclined with respect to the target traveling direction identified in S1803, that is, that the target yaw angle of the excavator 100 is different from “0” degrees (S1805: YES), the communication control part 301 transmits a signal indicating a warning to correct the traveling direction to the remote control room RC via the communication device T1 (S1806).

After that, the correcting part 306 corrects the operation signal so that the traveling direction of the excavator 100 becomes the target traveling direction, that is, that the traveling direction of the excavator 100 is the direction indicated by the target yaw angle (S1807). In the present embodiment, an example of correcting the operation signal so that the excavator 100 travels in accordance with the target traveling direction before the inclination angle is switched will be described, but the correction method is not limited to this, and the operation signal may be corrected so that the excavator 100 travels in accordance with the target traveling direction at the timing when the inclination angle is switched or after the inclination angle is switched.

Then, the actuator driving part 307 generates and outputs an actuation signal for controlling the lower traveling body 1 from the operation signal, and the process ends (S1808).

In the present embodiment, when it is determined that the traveling direction is inclined from the target traveling direction, an example of controlling the lower traveling body 1 to make the traveling direction of the excavator 100 and the inclined direction substantially parallel has been described, but the method of this control is not limited. For example, the controller 30 may perform control to correct the operation signal on the condition that the angle of the traveling direction of the excavator 100 with respect to the target traveling direction exceeds a predetermined angle.

FIG. 9 is an explanatory diagram illustrating the traveling trajectories of the crawlers when the controller 30 according to the present embodiment controls the lower traveling body 1. FIG. 9 illustrates an example in which the ground 1900A, which is substantially horizontal, changes to the ground 1900B, which is inclined at a first reference angle or more.

The target traveling direction identifying part 304 of the controller 30 identifies the ground shape based on the captured image obtained by the imaging device S6 of the excavator 100. That is, the target traveling direction identifying part 304 identifies the ground 1900A and the ground 1900B, and then identifies the area 1905 where the ground 1900A and the ground 1900B are switched.

On the ground 1900A, the excavator 100 travels in the traveling direction indicated by the traveling trajectories 1901 and 1902. When the excavator 100 travels without changing the traveling direction, it travels on the ground 1900B as indicated by the traveling trajectories 1911 and 1912. In this case, because the traveling direction of the excavator 100 is inclined compared with the inclined direction, there is a possibility that the excavator 100 will overturn.

Therefore, the controller 30 according to the present embodiment performs the control illustrated in FIG. 8. That is, before the excavator 100 reaches the area 1905, that is, before switching from the ground 1900A to the ground 1900B, the controller 30 corrects the operation signal so that the traveling direction is substantially parallel to the inclined direction of the ground 1900B. Thus, the traveling direction of the excavator 100 is switched to the traveling direction indicated by the traveling trajectories 1903 and 1904. Therefore, because the excavator 100 can travel in the traveling direction substantially parallel to the inclined direction, the possibility of overturn can be reduced and safety can be improved.

A description of an example has been given in which the controller 30 according to the present embodiment corrects the received operation signal so that the traveling direction is substantially parallel to the inclined direction. However, the present embodiment is not limited to the example of correcting the received operation direction. For example, the controller 30 may generate an operation signal such that the traveling direction is substantially parallel to the inclined direction. As a modified example, when the traveling direction of the excavator 100 is considerably inclined compared to the inclined direction, the controller 30 may apply a method of generating an operation signal for correcting the inclination rather than correcting the operation signal.

In the present embodiment, a description of an example has been given in which the determining part 305 controls the lower traveling body 1 when the inclination angle of the ground calculated by the inclination angle calculating part 303 is greater than or equal to the first reference angle (one example of a predetermined threshold). However, the present embodiment is not limited to an example of controlling the lower traveling body 1 only when the inclination angle of the ground is greater than or equal to the first reference angle (one example of a predetermined threshold). For example, the above-described control of the lower traveling body 1 may be constantly performed.

Further, in the present embodiment, a description of an example has been given in which the lower traveling body 1 is controlled so that the traveling direction of the excavator 100 and the inclined direction are substantially parallel. However, the present embodiment is not limited to controlling the lower traveling body 1 so that the traveling direction of the excavator 100 and the inclined direction are substantially parallel. It is also possible to control the inclination of the traveling direction of the excavator 100 to be within a predetermined angle with respect to the inclined direction of the ground. The predetermined angle may be determined in accordance with embodiments such as the shape and speed of the excavator 100 so that the overturn of the excavator 100 can be prevented. For example, the predetermined angle may be set to 5 degrees.

In the present embodiment, an example in which the controller 30 controls the lower traveling body 1 by correcting the operation signal has been described. However, the present embodiment is not limited to the method in which the controller 30 corrects the operation signal, and for example, the remote controller R30 may correct the operation signal.

When the excavator 100 is remotely operated as in the present embodiment, it is difficult for the operator OP to identify the situation around the excavator 100 or the direction of the crawler of the excavator 100 only from the information displayed on the display device DR. Further, there is a delay until the contents detected by the excavator 100 are displayed on the display device DR. Therefore, it is difficult for the operator OP to recognize the slip of the excavator 100 or to respond to the slip. On the other hand, because the controller 30 according to the present embodiment automatically controls the lower traveling body 1 of the excavator 100 by performing the control described above, safety can be improved.

Modified Example 1 of the First Embodiment

In the above-described embodiment, a description is given of an example in which the traveling direction is corrected so as to follow the target traveling direction when the inclination angle of the ground is switched. However, in the above-described embodiment, such correction may not necessarily be performed. For example, the traveling direction of the excavator 100 may be maintained even when the inclination angle of the ground is switched. Then, the controller 30 controls the lower traveling body 1 so that the traveling direction follows the extended path.

Then, when the traveling direction deviates from the extended path or when the pitch angle and the roll angle of the lower traveling body 1 change sharply, the excavator 100 is considered to have slipped, and the controller 30 corrects the operation signal so that the excavator 100 proceeds along the path. Because the traveling direction is maintained by this control even when the excavator 100 slips, the excavator 100 can be prevented from overturning.

Modified Example 2 of the First Embodiment

The above-described embodiment described an example in which the combination of the body inclination sensor S4 and the turning angle sensor S5 functions as an inclination recognition device for recognizing the inclination of the ground on which the excavator 100 is traveling. However, the above-described embodiment does not limit the inclination recognition device for recognizing the inclination of the ground to the combination of the body inclination sensor S4 and the turning angle sensor S5.

Therefore, modified example 2 of the first embodiment is an example in which the configuration in which the map information storage part 30A1 which stores the map information of the world coordinate system illustrating the inclination of the ground and the positioning device PS which acquires the position information of the world coordinate system of the excavator 100 are combined, is used as an inclination recognition device.

The inclination angle calculating part 303 according to this modified example refers to the map information to derive the inclination angle and the inclined direction of the ground corresponding to the position indicated by the position information. Further, the inclination angle calculating part 303 calculates the traveling direction of the excavator 100 from the change in the position of the excavator 100 with the passage of time as indicated by a plurality of pieces of position information, and calculates the pitch angle and the roll angle of the lower traveling body 1 from the traveling direction and the inclination angle and the inclined direction of the ground.

The description of the other processing is omitted as it is the same as the above-described embodiment. In this modified example, the possibility of the excavator 100 overturning can be reduced by performing the above-described control as in the above-described embodiment, thereby improving safety.

Second Embodiment

In the above-described embodiment, an example in which the operator OP operates the excavator 100 from the remote control room RC has been described. However, the above-described embodiment is not limited to the method in which the operator OP operates the excavator 100 from the remote control room RC. In the second embodiment, a case in which the operator seated in the cabin 10 operates the excavator 100 will be described.

In the present embodiment, the operator operates the excavator 100 using the operation device 26. Then, the acquiring part 302, acquires from the operation sensor 29, an operation signal indicating the operation contents of the operation device 26 detected by the operation sensor 29.

The following processing is the same as in the above-described embodiment, and descriptions thereof will be omitted. In the present embodiment, even when the operator operates the excavator from the cabin 10, the same effect as the above-described embodiment can be obtained.

Third Embodiment

In the above-described embodiment, an example in which the operator operates the excavator 100 has been described. However, the above-described embodiments are not limited to the case where an operator operates the excavator 100. As the third embodiment, a case in which the controller 30 performs autonomous control of the excavator 100 will be described.

The controller 30 according to the present embodiment implements a machine control function by reading a program stored in the auxiliary storage device 30A.

For example, according to work data stored in the auxiliary storage device 30A, the controller 30 controls the attachment AT, controls the turning of the upper turning body 3, and controls the traveling of the lower traveling body 1.

For example, the controller 30 generates a path for the lower traveling body 1 to travel, and controls the traveling of the lower traveling body 1 to travel along the path.

For example, when there is an inclined plane between the current position and the destination, the controller 30 generates a path so as to be substantially parallel to the inclined direction of the inclined plane. Then, the controller 30 generates an operation signal to move along the path. Then, the actuator driving part 307 generates and outputs an actuation signal to control the lower traveling body 1 from the operation signal.

Further, when it is determined that the inclination angle of the ground is greater than or equal to the first reference angle and that the roll angle is greater than or equal to the first reference angle, the controller 30 corrects the operation signal so as to cause the lower traveling body 1 to perform control for making the traveling direction of the excavator 100 and the inclined direction substantially parallel. The specific correction method is the same as that of the first embodiment and the description thereof is omitted. In the present embodiment, even when autonomous control is performed, the same effect as that of the above-described embodiment can be obtained.

In the above-described embodiments and modified examples, the controller 30 controls the lower traveling body 1 so that the inclination of the traveling direction of the excavator 100 with respect to the inclined direction of the ground is within a predetermined angle, for example, the traveling direction is substantially parallel to the inclined direction by performing the above-described control, thereby preventing the overturn of the excavator 100 and improving safety.

The excavator control system and the excavator according to an embodiment of the present invention have been described above, but the present invention is not limited to the above-described embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. These also naturally fall within the technical scope of the present invention.

CONTROL SYSTEM FOR EXCAVATOR AND EXCAVATOR

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CPC

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Priority Claims (1)