JP2017223096A - Shovel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shovel capable of more appropriately controlling a drilling attachment in performing deep drilling.SOLUTION: A shovel according to an embodiment of the present invention includes: a lower traveling body 1: a revolving super structure 3 mounted on the lower traveling body 1; a drilling attachment attached to the revolving super structure 3; a posture detection device M1 for detecting a posture of the drilling attachment; a cylinder pressure sensor S1 for detecting information on a drilling load; and a controller 30 for correcting the posture of the drilling attachment. The controller 30 is configured to open an arm 5 or a bucket 6 that constitute the drilling attachment when it is determined on the basis of output of the posture detection device M1 and the cylinder pressure sensor S1 that a drilling load during deep drilling is larger than a predetermined value.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an excavator capable of detecting the attitude of a digging attachment.

  By determining the excavation reaction force from the position and posture of the work element without attaching a load detector to the work element such as a boom, arm, and bucket, it is determined whether or not an overload has occurred in the excavation operation, and the operation of the work element is determined. A shovel that can be controlled is known (see Patent Document 1).

  When the calculated excavation reaction force is larger than the preset upper limit value, the excavator can increase the boom automatically during the excavation operation to reduce the excavation reaction force by reducing the excavation reaction force. Prevents stopping on the way.

JP 2011-252338 A

  However, when deep excavation is performed, if the boom is raised to reduce the excavation depth, the excavation reaction force may be increased. In this regard, the excavator of Patent Document 1 raises the boom regardless of whether deep excavation or normal excavation is performed if the calculated excavation reaction force is greater than a preset upper limit value. Therefore, the excavation reaction force is increased in an attempt to reduce the excavation reaction force during deep excavation, and there is a risk that the deep excavation cannot be continued and work efficiency is reduced.

  In view of the above, it is desirable to provide an excavator that can more appropriately control excavation attachments during deep excavation.

  An excavator according to an embodiment of the present invention includes a lower traveling body, an upper swing body mounted on the lower traveling body, a drilling attachment attached to the upper swing body, and a posture detection device that detects the posture of the drilling attachment. A excavation load information detection device for detecting information related to excavation load, and a control device for correcting the posture of the excavation attachment, wherein the control device includes the posture detection device and the excavation load information detection When it is determined that the excavation load during deep excavation is larger than a predetermined value based on the output of the apparatus, the arm or bucket constituting the excavation attachment is opened.

  By the above-described means, an excavator capable of more appropriately controlling the excavation attachment during deep excavation is provided.

It is a side view of the shovel which concerns on the Example of this invention. It is a side view of the shovel which shows various physical quantities relevant to the excavation attachment of the shovel of FIG. It is a figure which shows the structural example of the basic system mounted in the shovel of FIG. It is a figure which shows the structural example of the excavation control system mounted in the shovel of FIG. It is a side view of the shovel which shows transition of the attitude | position of a digging attachment. It is a flowchart of a posture correction necessity determination process. It is a flowchart which shows an example of the flow of a net excavation load calculation process. It is a flowchart which shows another example of the flow of a net excavation load calculation process. It is a figure which shows the time transition of the bucket angle and excavation reaction force when combined operation of arm closing operation and boom raising operation is performed.

  Initially, with reference to FIG. 1, the shovel (excavator) as a construction machine based on the Example of this invention is demonstrated. FIG. 1 is a side view of an excavator according to an embodiment of the present invention. An upper swing body 3 is turnably mounted on a lower traveling body 1 of the shovel shown in FIG. 1 via a swing mechanism 2. A boom 4 is attached to the upper swing body 3. An arm 5 is attached to the tip of the boom 4, and a bucket 6 is attached to the tip of the arm 5. The boom 4, the arm 5, and the bucket 6 as work elements constitute a drilling attachment that is an example of an attachment. The boom 4, the arm 5, and the bucket 6 are hydraulically driven by a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9, respectively. The upper swing body 3 is provided with a cabin 10 and is mounted with a power source such as an engine 11.

  An attitude detection device M1 is attached to the excavation attachment. The posture detection device M1 is a device that detects the posture of the excavation attachment. In the present embodiment, the attitude detection device M1 includes a boom angle sensor M1a, an arm angle sensor M1b, and a bucket angle sensor M1c.

  The boom angle sensor M1a is a sensor that acquires a boom angle. For example, a rotation angle sensor that detects a rotation angle of a boom foot pin, a stroke sensor that detects a stroke amount of the boom cylinder 7, and an inclination angle of the boom 4 are detected. Includes tilt (acceleration) sensors and the like. The same applies to the arm angle sensor M1b and the bucket angle sensor M1c.

  FIG. 2 is a side view of the excavator showing various physical quantities related to the excavation attachment. The boom angle sensor M1a acquires, for example, a boom angle (θ1). The boom angle (θ1) is an angle with respect to the horizontal line of the line segment P1-P2 connecting the boom foot pin position P1 and the arm connecting pin position P2 in the XZ plane. The arm angle sensor M1b acquires an arm angle (θ2), for example. The arm angle (θ2) is an angle with respect to the horizontal line of the line segment P2-P3 connecting the arm connecting pin position P2 and the bucket connecting pin position P3 in the XZ plane. For example, the bucket angle sensor M1c acquires a bucket angle (θ3). The bucket angle (θ3) is an angle with respect to the horizontal line of the line segment P3-P4 connecting the bucket connecting pin position P3 and the bucket toe position P4 in the XZ plane.

  Next, the basic system of the shovel will be described with reference to FIG. The basic system of the excavator mainly includes an engine 11, a main pump 14, a pilot pump 15, a control valve 17, an operating device 26, a controller 30, an engine control device 74, and the like.

  The engine 11 is an excavator drive source, and is, for example, a diesel engine that operates to maintain a predetermined rotational speed. The output shaft of the engine 11 is connected to the input shafts of the main pump 14 and the pilot pump 15.

  The main pump 14 is a hydraulic pump that supplies hydraulic oil to the control valve 17 via the high-pressure hydraulic line 16, and is, for example, a swash plate type variable displacement hydraulic pump. In the swash plate type variable displacement hydraulic pump, the stroke length of the piston that determines the displacement is changed according to the change in the swash plate tilt angle, and the discharge flow rate per one rotation changes. The swash plate tilt angle is controlled by the regulator 14a. The regulator 14 a changes the swash plate tilt angle according to the change in the control current from the controller 30. For example, the regulator 14a increases the discharge flow rate of the main pump 14 by increasing the tilt angle of the swash plate according to the increase of the control current. Alternatively, the regulator 14a decreases the discharge flow rate of the main pump 14 by reducing the swash plate tilt angle according to the decrease in the control current. The discharge pressure sensor 14b detects the discharge pressure of the main pump 14. The oil temperature sensor 14c detects the temperature of the hydraulic oil sucked by the main pump 14.

  The pilot pump 15 is a hydraulic pump for supplying hydraulic oil to various hydraulic control devices such as the operation device 26 via the pilot line 25, and is, for example, a fixed displacement hydraulic pump.

  The control valve 17 is a set of flow rate control valves for controlling the flow of hydraulic oil related to the hydraulic actuator. The control valve 17 selectively supplies hydraulic oil received from the main pump 14 through the high-pressure hydraulic line 16 to one or a plurality of hydraulic actuators in response to changes in pressure corresponding to the operation direction and operation amount of the operation device 26. The hydraulic actuator includes, for example, a boom cylinder 7, an arm cylinder 8, a bucket cylinder 9, a left traveling hydraulic motor 1A, a right traveling hydraulic motor 1B, and a turning hydraulic motor 2A.

  The operating device 26 is a device used by an operator for operating the hydraulic actuator, and includes a lever 26A, a lever 26B, a pedal 26C, and the like. The operating device 26 receives the supply of hydraulic oil from the pilot pump 15 via the pilot line 25 and generates a pilot pressure. Then, the pilot pressure is applied to the pilot port of the corresponding flow control valve through the pilot line 25a. The pilot pressure changes according to the operation direction and the operation amount of the operation device 26. The operating device 26 may be remotely operated. In this case, the controller device 26 generates a pilot pressure according to the information regarding the operation direction and the operation amount received via wireless communication.

  The controller 30 is a control device for controlling the shovel. In this embodiment, the controller 30 is composed of a computer having a CPU, RAM, ROM and the like. The CPU of the controller 30 reads out programs corresponding to various functions from the ROM, loads them into the RAM, and executes them, thereby realizing the functions corresponding to the programs.

  For example, the controller 30 realizes a function of controlling the discharge flow rate of the main pump 14. Specifically, the controller 30 changes the control current for the regulator 14a according to the negative control pressure of the negative control valve, and controls the discharge flow rate of the main pump 14 via the regulator 14a.

  The engine control device 74 is a device that controls the engine 11. For example, the engine control device 74 controls the fuel injection amount and the like so that the engine speed set via the input device is realized.

  The operation mode switching dial 75 is a dial for switching the operation mode of the shovel and is provided in the cabin 10. In this embodiment, the operator can switch between the M (manual) mode and the SA (semi-automatic) mode. For example, the controller 30 switches the operation mode of the shovel according to the output of the operation mode switching dial 75. FIG. 3 shows a state where the SA mode is selected with the operation mode switching dial 75.

  The M mode is a mode in which the excavator is operated according to the content of operation input to the operation device 26 by the operator. For example, in this mode, the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 are operated according to the content of the operation input to the operation device 26 by the operator. The SA mode is a mode in which the shovel is automatically operated regardless of the content of the operation input to the operation device 26 when a predetermined condition is satisfied. For example, when a predetermined condition is satisfied, the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 are automatically operated regardless of the content of the operation input to the operation device 26. The operation mode switching dial 75 may be configured to be able to switch between three or more operation modes.

  The display device 40 is a device that displays various types of information, and is disposed in the vicinity of the driver's seat in the cabin 10. In the present embodiment, the display device 40 includes an image display unit 41 and an input unit 42. An operator can input information and commands to the controller 30 using the input unit 42. Further, the operation status and control information of the excavator can be grasped by looking at the image display unit 41. The display device 40 is connected to the controller 30 via a communication network such as CAN. However, the display device 40 may be connected to the controller 30 via a dedicated line.

  The display device 40 operates by receiving power from the storage battery 70. The storage battery 70 is charged with the electric power generated by the alternator 11a. The electric power of the storage battery 70 is also supplied to parts other than the controller 30 and the display device 40 such as the excavator electrical component 72. The starter 11b of the engine 11 is driven by electric power from the storage battery 70 to start the engine 11.

  The engine 11 is controlled by an engine control device 74. The engine control device 74 transmits various data indicating the state of the engine 11 (for example, data indicating the cooling water temperature (physical quantity) detected by the water temperature sensor 11c) to the controller 30. The controller 30 can store the data in the temporary storage unit (memory) 30a and transmit it to the display device 40 as necessary. Data indicating the tilt angle of the swash plate output from the regulator 14a, data indicating the discharge pressure of the main pump 14 output from the discharge pressure sensor 14b, data indicating the hydraulic oil temperature output from the oil temperature sensor 14c, a pilot pressure sensor 15a, The same applies to data indicating the pilot pressure output by 15b.

  The cylinder pressure sensor S <b> 1 is an example of an excavation load information detection device that detects information related to excavation load, detects the cylinder pressure of the hydraulic cylinder, and outputs detection data to the controller 30. In the present embodiment, the cylinder pressure sensor S1 includes cylinder pressure sensors S11 to S16. Specifically, the cylinder pressure sensor S <b> 11 detects a boom bottom pressure that is a pressure of hydraulic oil in the bottom side oil chamber of the boom cylinder 7. The cylinder pressure sensor S12 detects a boom rod pressure that is a pressure of hydraulic oil in the rod side oil chamber of the boom cylinder 7. Similarly, the cylinder pressure sensor S13 detects the arm bottom pressure, the cylinder pressure sensor S14 detects the arm rod pressure, the cylinder pressure sensor S15 detects the bucket bottom pressure, and the cylinder pressure sensor S16 detects the bucket rod pressure. .

  The control valve E <b> 1 is a valve that operates according to a command from the controller 30. In the present embodiment, the control valve E1 is used for forcibly operating the flow control valve related to a predetermined hydraulic cylinder regardless of the content of the operation input to the operation device 26.

  FIG. 4 is a diagram illustrating a configuration example of an excavation control system mounted on the excavator in FIG. 1. The excavation control system mainly includes an attitude detection device M1, a cylinder pressure sensor S1, a controller 30, and a control valve E1. The controller 30 includes a posture correction necessity determination unit 31.

  The posture correction necessity determination unit 31 is a functional element that determines whether or not the posture of the excavation attachment during excavation should be corrected. For example, when it is determined that the excavation load may become excessively large, the posture correction necessity determination unit 31 determines that the posture of the excavation attachment during excavation should be corrected.

  In the present embodiment, the posture correction necessity determination unit 31 derives and records the excavation load based on the output of the cylinder pressure sensor S1. Further, an empty excavation load corresponding to the attitude of the excavation attachment detected by the attitude detection device M1 is derived. Then, the posture correction necessity determination unit 31 calculates the net excavation load by subtracting the empty excavation load from the excavation load, and determines whether or not the posture of the excavation attachment should be corrected based on the net excavation load. The posture correction necessity determination unit 31 may consider the inclination of the upper swing body 3 detected by the vehicle body inclination sensor when deriving the empty excavation load. The vehicle body tilt sensor includes, for example, an acceleration sensor, a gyro sensor, and the like.

  “Drilling” means moving the drilling attachment while bringing the drilling attachment into contact with the object to be excavated, such as earth and sand. “Drilling” means moving the drilling attachment without bringing the drilling attachment into contact with any feature. To do.

  “Drilling load” means a load when the excavation attachment is moved while being in contact with the excavation object, and “empty excavation load” is a load when the excavation attachment is moved without contacting any feature. “Drilling load” is also referred to as “digging resistance”.

  “Excavation load”, “empty excavation load”, and “net excavation load” are each expressed by an arbitrary physical quantity such as cylinder pressure, cylinder thrust, excavation torque (moment of excavation force), excavation reaction force, and the like. For example, the net cylinder pressure as the net excavation load is expressed as a value obtained by subtracting the empty excavation cylinder pressure as the empty excavation load from the cylinder pressure as the excavation load. The same applies to the case of using cylinder thrust, excavation torque (moment of excavation force), excavation reaction force, and the like.

  As the cylinder pressure, for example, a detection value of the cylinder pressure sensor S1 is used. The detection value of the cylinder pressure sensor S1 is, for example, boom bottom pressure (P11), boom rod pressure (P12), arm bottom pressure (P13), arm rod pressure (P14), bucket bottom detected by the cylinder pressure sensors S11 to S16. Pressure (P15) and bucket rod pressure (P16).

  The cylinder thrust is calculated based on, for example, the cylinder pressure and the pressure receiving area of a piston that slides in the cylinder. For example, as shown in FIG. 2, the boom cylinder thrust (f1) is a cylinder extension force that is the product (P11 × A11) of the boom bottom pressure (P11) and the pressure receiving area (A11) of the piston in the boom bottom side oil chamber. And the difference (P11 × A11−P12 × A12) between the cylinder rod contraction force that is the product (P12 × A12) of the boom rod pressure (P12) and the piston pressure receiving area (A12) in the boom rod side oil chamber. The The same applies to the arm cylinder thrust (f2) and the bucket cylinder thrust (f3).

  The excavation torque is calculated based on, for example, the attitude of the excavation attachment and the cylinder thrust. For example, as shown in FIG. 2, the magnitude of the bucket excavation torque (τ3) is equal to the magnitude of the bucket cylinder thrust (f3), and the distance between the line of action of the bucket cylinder thrust (f3) and the bucket connecting pin position P3. It is expressed as a value multiplied by G3. The distance G3 is a function of the bucket angle (θ3) and is an example of a link gain. The same applies to the boom excavation torque (τ1) and the arm excavation torque (τ2).

  The excavation reaction force is calculated based on, for example, the attitude of the excavation attachment and the excavation load. For example, the excavation reaction force F is calculated based on a function (mechanism function) that uses a physical quantity that represents the attitude of the excavation attachment as an argument and a function that uses a physical quantity that represents the excavation load as an argument. Specifically, the excavation reaction force F includes a boom function (θ1), an arm angle (θ2), and a bucket function (θ3) as arguments as shown in FIG. 2, a boom excavation torque (τ1), It is calculated as a product of the arm excavation torque (τ2) and the function having the bucket excavation torque (τ3) as arguments. The functions having the boom excavation torque (τ1), arm excavation torque (τ2), and bucket excavation torque (τ3) as arguments are the boom cylinder thrust (f1), arm cylinder thrust (f2), and bucket cylinder thrust (f3). It may be a function as an argument.

  The functions having the boom angle (θ1), arm angle (θ2), and bucket angle (θ3) as arguments may be based on a force balance equation, may be based on a Jacobian, It may be based on the principle of

  In this way, the excavation load is derived based on the current detection values of various sensors. For example, the detected value of the cylinder pressure sensor S1 may be used as it is as an excavation load. Or the cylinder thrust calculated based on the detected value of cylinder pressure sensor S1 may be utilized as a digging load. Alternatively, the excavation torque calculated from the cylinder thrust calculated based on the detection value of the cylinder pressure sensor S1 and the attitude of the excavation attachment derived based on the detection value of the attitude detection device M1 may be used as the excavation load. Good. The same applies to the excavation reaction force.

  On the other hand, the empty excavation load may be stored in advance in association with the attitude of the excavation attachment. For example, an empty excavation cylinder pressure table is used that stores an empty excavation cylinder pressure as an empty excavation load in association with a combination of a boom angle (θ1), an arm angle (θ2), and a bucket angle (θ3). Also good. Alternatively, an empty excavation cylinder thrust table is used that stores an empty excavation cylinder thrust as an empty excavation load so that it can be referred to in association with a combination of the boom angle (θ1), arm angle (θ2), and bucket angle (θ3). Also good. The same applies to the empty excavation torque table and the empty excavation reaction force table. The empty excavation cylinder pressure table, the empty excavation cylinder thrust table, the empty excavation torque table, and the empty excavation reaction force table are generated based on data acquired when performing an empty excavation with an actual excavator, for example. It may be stored in advance in a ROM or the like. Alternatively, it may be generated based on a simulation result derived by a simulator device such as an excavator simulator. Further, instead of the reference table, a calculation formula such as a multiple regression formula based on multiple regression analysis may be used. When the multiple regression equation is used, the empty excavation load is calculated in real time based on, for example, a combination of the current boom angle (θ1), arm angle (θ2), and bucket angle (θ3).

  Further, the empty drilling cylinder pressure table, the empty drilling cylinder thrust table, the empty drilling torque table, and the empty drilling reaction force table may be prepared for each operation speed of the drilling attachment such as high speed, medium speed, and low speed. Moreover, you may prepare for every operation | movement content of excavation attachment at the time of arm closing, arm opening, boom raising, boom lowering.

  When the current net excavation load is equal to or greater than a predetermined value, the posture correction necessity determination unit 31 determines that the excavation load may be excessive. For example, the posture correction necessity determination unit 31 determines that the cylinder pressure as the excavation load may be excessive when the net cylinder pressure as the net excavation load is equal to or higher than a predetermined cylinder pressure. The predetermined cylinder pressure may be a fluctuation value that changes in accordance with a change in the attitude of the excavation attachment, or may be a fixed value that does not change in accordance with a change in the attitude of the excavation attachment.

  If it is determined that the excavation load may be excessive when the operation mode is the SA (semi-automatic) mode, the posture correction necessity determination unit 31 determines that the posture of the excavation attachment during excavation should be corrected. Then, a command is output to the control valve E1.

  The control valve E1 that has received a command from the posture correction necessity determination unit 31 forcibly operates the flow rate control valve related to the predetermined hydraulic cylinder regardless of the content of the operation input to the operating device 26, thereby causing the predetermined hydraulic cylinder to operate. Force it to expand and contract. In the present embodiment, the control valve E1 forcibly extends the boom cylinder 7 by forcibly moving the flow control valve related to the boom cylinder 7 even when the boom operation lever is not operated. As a result, the excavation depth can be reduced by forcibly raising the boom 4. Alternatively, the control valve E1 may forcibly extend the bucket cylinder 9 by forcibly moving the flow control valve related to the bucket cylinder 9 even when the bucket operation lever is not operated. In this case, the excavation depth can be reduced by forcibly closing the bucket 6 to adjust the bucket toe angle. The bucket toe angle is, for example, the angle of the toe of the bucket 6 with respect to the horizontal plane. Thus, the control valve E1 can make the digging depth shallow by forcibly extending and contracting at least one of the boom cylinder 7 and the bucket cylinder 9.

  However, when deep excavation is performed, if the boom 4 is forcibly raised or the bucket 6 is closed to reduce the excavation depth, the excavation reaction force may be increased. Accordingly, the posture correction necessity determination unit 31 makes the correction content of the posture of the excavation attachment when deep excavation is performed different from the correction content as described above when normal excavation is performed.

  For example, the posture correction necessity determination unit 31 determines whether deep excavation or normal excavation is in progress based on the posture of the excavation attachment. The posture correction necessity determination unit 31 determines whether deep excavation or normal excavation is being performed based on the posture of the boom 4 or based on the posture of the boom 4 and the posture of the arm 5. Good.

  Here, the difference between normal excavation and deep excavation will be described with reference to FIG. FIG. 5 is a side view of the shovel showing the transition of the posture of the excavation attachment. 5 (A1) to FIG. 5 (A3) show the transition of the posture of the excavation attachment when normal excavation is performed, and FIG. 5 (B1) to FIG. 5 (B3) are when deep excavation is performed. The transition of the posture of the drilling attachment is shown.

  “Normal excavation” means excavation when there is no possibility that the moment of excavation reaction force that tries to rotate the excavator forward exceeds the moment of the excavator's own weight that prevents the excavator from moving forward. Typically, as shown in FIG. 5 (A1) to FIG. 5 (A3), the excavation depth D1 is excavation less than a predetermined depth (for example, 2 meters). The excavation depth means, for example, the depth of the point of action of the excavation reaction force on the horizontal plane including the ground contact surface of the lower traveling body 1. When the point of action of the excavation reaction force is higher than the horizontal plane, the excavation depth is a negative value, meaning the excavation height.

  “Deep excavation” means excavation when the moment of excavation reaction force that attempts to forward the excavator may exceed the moment of the weight of the excavator that prevents the excavator from moving forward. Typically, as shown in FIG. 5 (B1) to FIG. 5 (B3), the excavation depth D2 is excavation with a predetermined depth (for example, 2 meters) or more.

  The posture correction necessity determination unit 31 determines whether or not the bucket 6 is in contact with the ground based on outputs from the pilot pressure sensors 15a and 15b, the cylinder pressure sensors S11 to S16, and the like. This is to determine whether or not excavation is in progress.

  Then, the posture correction necessity determination unit 31 derives the bucket toe position P4 based on the detection value of the posture detection device M1, and when the value of the Z coordinate of the bucket toe position P4 is a negative value, the absolute value is determined as the digging depth. To do. If the excavation depth is not less than the predetermined depth, it is determined that the excavation is deep excavation, and if the excavation depth is less than the predetermined depth, it is determined that the excavation is normal excavation.

  Thereafter, the posture correction necessity determination unit 31 determines whether or not the excavation load may be excessive. If it is determined that the excavation load may be excessive during normal excavation, the posture correction necessity determination unit 31 forcibly raises the boom 4 by forcibly extending the boom cylinder 7 as described above. Let

  On the other hand, when it is determined that the excavation load may be excessive during deep excavation, the posture correction necessity determination unit 31 forcibly contracts the arm cylinder 8 instead of forcibly raising the boom 4. The arm 5 is forcibly opened. Alternatively, the bucket 6 is forcibly contracted to open the bucket 6 forcibly. You may open the arm 5 and the bucket 6 simultaneously. This is to reduce the excavation reaction force, and when deep excavation is being performed, if the boom 4 is forcibly raised to reduce the excavation depth, the excavation reaction force may be increased.

  The posture correction necessity determination unit 31 determines whether or not the excavation load may be excessive during deep excavation based on the output of the vehicle body inclination sensor attached to the rear end of the upper swing body 3. Also good. The posture correction necessity determination unit 31 may exceed the moment of the excavator's own weight that prevents the excavator from rotating forward based on the inclination of the upper swing body 3. This is because it can be determined whether or not.

  Further, the posture correction necessity determination unit 31 may determine whether the excavation load is excessive or not and then determine whether the excavation load is normal excavation or deep excavation. Also, the determination of whether or not excavation is in progress may be omitted. Alternatively, the determination as to whether or not excavation is being performed, the determination as to whether excavation is normal or deep excavation, and the determination as to whether or not the excavation load may be excessive may be performed simultaneously.

  Next, referring to FIG. 6, the controller 30 determines whether or not the posture of the excavation attachment needs to be corrected during excavation by the arm closing operation (hereinafter referred to as “posture correction necessity determination processing”). The flow will be described. FIG. 6 is a flowchart of the posture correction necessity determination process. When the operation mode is set to the SA (semi-automatic) mode, the controller 30 repeatedly executes this posture correction necessity determination process at a predetermined control cycle.

  First, the posture correction necessity determination unit 31 of the controller 30 acquires data related to the excavation attachment (step ST1). The posture correction necessity determination unit 31 acquires, for example, a boom angle (θ1), an arm angle (θ2), a bucket angle (θ3), a cylinder pressure (P11 to P16), and the like.

  Thereafter, the posture correction necessity determination unit 31 executes a net excavation load calculation process to calculate a net excavation load (step ST2). Details of the net excavation load calculation process will be described later.

  Thereafter, the posture correction necessity determination unit 31 determines whether or not the bucket 6 is in contact with the ground (step ST3). This is to determine whether or not it is in an excavation state. The posture correction necessity determination unit 31 determines whether or not the bucket 6 is in contact with the ground based on outputs from the pilot pressure sensors 15a and 15b, the cylinder pressure sensors S11 to S16, and the like. For example, it is determined that the bucket 6 is in contact with the ground when the arm bottom pressure (P13), which is the pressure of hydraulic oil in the extension side oil chamber during the arm closing operation, is equal to or higher than a predetermined value. Whether or not the arm closing operation is performed is determined based on the outputs of the pilot pressure sensors 15a and 15b.

  When it is determined that the bucket 6 is in contact with the ground (YES in step ST3), the posture correction necessity determination unit 31 determines whether or not the excavation load may be excessive (step ST4). For example, the posture correction necessity determination unit 31 determines that the excavation load may be excessive when the net excavation load calculated in the net excavation load calculation process is equal to or greater than a predetermined value.

  When it is determined that the excavation load may be excessive (YES in step ST4), the posture correction necessity determination unit 31 determines whether the excavation is normal excavation or deep excavation (step ST5). The posture correction necessity determination unit 31 determines, for example, whether the excavation attachment is normal excavation or deep excavation based on the posture of the excavation attachment detected by the posture detection device M1. Specifically, for example, the posture correction necessity determination unit 31 determines that deep excavation is performed when the excavation depth is equal to or greater than a predetermined depth, and determines that normal excavation is performed when the excavation depth is less than the predetermined depth.

  When it is determined that the excavation is normal (ordinary excavation in step ST5), the posture correction necessity determination unit 31 executes adjustment processing during normal excavation on the assumption that the posture of the excavation attachment needs to be corrected during normal excavation ( Step ST6). For example, the posture correction necessity determination unit 31 outputs a command to the control valve E1 and forcibly expands the boom cylinder 7 by forcibly moving the flow control valve related to the boom cylinder 7. As a result, the excavation depth can be reduced by forcibly raising the boom 4 regardless of whether or not there is an operation input to the boom operation lever. Alternatively, the posture correction necessity determination unit 31 may forcibly extend the bucket cylinder 9 by forcibly moving the flow control valve related to the bucket cylinder 9. As a result, the excavation depth can be reduced by forcibly closing the bucket 6 regardless of whether or not there is an operation input to the bucket operation lever.

  When it is determined that the excavation is deep excavation (deep excavation in step ST5), the posture correction necessity determination unit 31 performs adjustment processing during deep excavation because it is necessary to correct the posture of the excavation attachment during the deep excavation. (Step ST7). For example, the posture correction necessity determination unit 31 outputs a command to the control valve E1, and forcibly moves the flow control valve related to the arm cylinder 8 to forcibly contract the arm cylinder 8. As a result, the excavation load can be reduced by forcibly opening the arm 5 regardless of whether there is an operation input to the arm operation lever. Alternatively, the posture correction necessity determination unit 31 may forcibly contract the bucket cylinder 9 by forcibly moving the flow control valve related to the bucket cylinder 9. As a result, the excavation load can be reduced by forcibly opening the bucket 6 regardless of whether or not there is an operation input to the bucket operation lever.

  When it is determined that the bucket 6 is not in contact with the ground (NO in step ST3), or when it is determined that the excavation load is not likely to be excessive (NO in step ST4), the posture correction necessity determining unit 31 is Then, the current posture correction necessity determination process is terminated without executing the adjustment process.

  In the example of FIG. 6, the posture correction necessity determination unit 31 determines whether or not the excavation load may be excessive after determining that the bucket 6 has contacted the ground, and further, the excavation load is excessive. After determining that there is a risk of becoming, it is determined whether normal excavation or deep excavation. However, the posture correction necessity determination unit 31 may determine whether the excavation load may be excessive after determining whether the excavation is normal or deep excavation. Moreover, you may abbreviate | omit the determination whether the bucket 6 contacted the ground.

  Further, the posture correction necessity determination unit 31 determines whether or not the excavation load is likely to be excessive, but may determine whether or not the excavation load is likely to be excessive.

  And also when it determines with there exists a possibility that excavation load may become small, the attitude | position correction necessity determination part 31 may perform adjustment processing as it is necessary to correct the attitude | position of an excavation attachment.

  For example, when it is determined that the excavation load may be excessive during normal excavation, the posture correction necessity determination unit 31 outputs a command to the control valve E1 to force the flow control valve related to the boom cylinder 7 The boom cylinder 7 is forcibly contracted by moving to. As a result, the excavation depth can be increased by forcibly lowering the boom 4 regardless of whether or not there is an operation input to the boom operation lever. Alternatively, the posture correction necessity determination unit 31 may forcibly extend the bucket cylinder 9 by forcibly moving the flow control valve related to the bucket cylinder 9. As a result, the excavation depth can be increased by forcibly opening the bucket 6 regardless of whether or not there is an operation input to the bucket operation lever.

  Next, the flow of the net excavation load calculation process will be described with reference to FIG. FIG. 7 is a flowchart showing an example of the flow of the net excavation load calculation process.

  First, the posture correction necessity determination unit 31 acquires the cylinder pressure as the excavation load at the current time (step ST11). The cylinder pressure at the present time includes, for example, a boom bottom pressure (P11) detected by the cylinder pressure sensor S11. The same applies to the boom rod pressure (P12), the arm bottom pressure (P13), the arm rod pressure (P14), the bucket bottom pressure (P15), and the bucket rod pressure (P16).

  After that, the posture correction necessity determination unit 31 acquires an empty excavation cylinder pressure as an empty excavation load corresponding to the posture of the excavation attachment at the current time (step ST12). For example, the pre-stored empty excavation cylinder pressure is derived by referring to the empty excavation cylinder pressure table using the current boom angle (θ1), arm angle (θ2), and bucket angle (θ3) as search keys. The empty drilling cylinder pressure is, for example, at least one of an empty drilling boom bottom pressure, an empty drilling boom rod pressure, an empty drilling arm bottom pressure, an empty drilling arm rod pressure, an empty drilling bucket bottom pressure, and an empty drilling bucket rod pressure. including.

  After that, the posture correction necessity determination unit 31 calculates a net cylinder pressure by subtracting an empty excavation cylinder pressure corresponding to the current excavation attachment posture from the current cylinder pressure (step ST13). The net cylinder pressure includes, for example, a net boom bottom pressure obtained by subtracting the empty excavation boom bottom pressure from the boom bottom pressure (P11). The same applies to the net boom rod pressure, the net arm bottom pressure, the net arm rod pressure, the net bucket bottom pressure, and the net bucket rod pressure.

  Thereafter, the posture correction necessity determination unit 31 outputs the calculated net cylinder pressure as a net excavation load (step ST14).

  The posture correction necessity determination unit 31 determines whether or not the excavation load may be excessive based on at least one of the six net cylinder pressures when the six net cylinder pressures are derived as the net excavation load. judge. The six net cylinder pressures are net boom bottom pressure, net boom rod pressure, net arm bottom pressure, net arm rod pressure, net bucket bottom pressure, and net bucket rod pressure. For example, the posture correction necessity determination unit 31 determines that the net arm bottom pressure is not less than the first predetermined pressure value and the net boom bottom pressure is the second when the combined operation of the arm closing operation and the boom raising operation is performed. When the pressure is equal to or higher than the predetermined pressure value, it may be determined that the excavation load may be excessive. Alternatively, the posture correction necessity determination unit 31 may determine that the excavation load may be excessive when the net arm bottom pressure is equal to or higher than the first predetermined pressure value when the arm closing operation is performed. . Alternatively, the posture correction necessity determination unit 31 may determine that the excavation load may be excessive when the net boom bottom pressure is equal to or higher than the second predetermined pressure value when the boom raising operation is performed. Good.

  Next, another example of the net excavation load calculation process will be described with reference to FIG. FIG. 8 is a flowchart showing another example of the flow of the net excavation load calculation process. The process of FIG. 8 is different from the process of FIG. 7 using the cylinder pressure in that the cylinder thrust is used as the current excavation load.

  First, the posture correction necessity determination unit 31 calculates the cylinder thrust as the excavation load from the current cylinder pressure (step ST21). The cylinder thrust at the present time is, for example, a boom cylinder thrust (f1). The boom cylinder thrust (f1) is a cylinder extension force, which is a product (P11 × A11) of the boom bottom pressure (P11) and the pressure receiving area (A11) of the piston in the boom bottom side oil chamber, and the boom rod pressure (P12). This is the difference (P11 × A11−P12 × A12) from the cylinder contraction force, which is the product (P12 × A12) with the pressure receiving area (A12) of the piston in the boom rod side oil chamber. The same applies to the arm cylinder thrust (f2) and the bucket cylinder thrust (f3).

  Thereafter, the posture correction necessity determination unit 31 acquires an empty excavation cylinder thrust as an empty excavation load corresponding to the posture of the excavation attachment at the current time (step ST22). For example, by referring to the empty excavation cylinder thrust table using the current boom angle (θ1), arm angle (θ2), and bucket angle (θ3) as search keys, the empty excavation cylinder thrust stored in advance is derived. The empty drilling cylinder thrust includes, for example, at least one of an empty drilling boom cylinder thrust, an empty drilling arm cylinder thrust, and an empty drilling bucket cylinder thrust.

  Thereafter, the posture correction necessity determination unit 31 calculates the net cylinder thrust by subtracting the empty excavation cylinder thrust from the current cylinder thrust (step ST23). The net cylinder thrust includes, for example, a net boom cylinder thrust obtained by subtracting the empty excavation boom cylinder thrust from the current boom cylinder thrust (f1). The same applies to the net arm cylinder thrust and the net bucket cylinder thrust.

  Thereafter, the posture correction necessity determination unit 31 outputs the calculated net cylinder thrust as a net excavation load (step ST24).

  The posture correction necessity determination unit 31 determines whether or not the excavation load may be excessive based on at least one of the three net cylinder thrusts when the three net cylinder thrusts are derived as the net excavation load. judge. The three net cylinder thrusts are the net boom cylinder thrust, the net arm cylinder thrust, and the net bucket cylinder thrust. For example, the posture correction necessity determination unit 31 may cause an excessive excavation load when the net arm cylinder thrust is equal to or greater than a first predetermined thrust value and the net boom cylinder thrust is equal to or greater than a second predetermined thrust value. May be determined. Alternatively, the posture correction necessity determination unit 31 may determine that the excavation load may be excessive when the net arm cylinder thrust is equal to or greater than the first predetermined thrust value.

  Alternatively, when the posture correction necessity determination unit 31 derives the three net excavation torques as the net excavation load, whether or not the excavation load may be excessive based on at least one of the three net excavation torques. It may be determined. The three net drilling torques are net boom drilling torque, net arm drilling torque, and net bucket drilling torque. For example, the posture correction necessity determination unit 31 may cause an excessive excavation load when the net arm excavation torque is equal to or greater than a first predetermined torque value and the net boom excavation torque is equal to or greater than a second predetermined torque value. May be determined. Alternatively, the posture correction necessity determination unit 31 may determine that the excavation load may be excessive when the net arm excavation torque is equal to or greater than the first predetermined torque value.

  Next, with reference to FIG. 9, the temporal transition of the bucket angle (θ3) and the excavation reaction force F when the combined operation of the arm closing operation and the boom raising operation is performed will be described. 9A shows the temporal transition of the bucket angle (θ3), and FIG. 9B shows the temporal transition of the excavation reaction force F. The solid lines in FIGS. 9A and 9B indicate the transition during deep excavation, and the broken lines indicate the transition during normal excavation.

  The operator of the excavator makes excavation from time t0 to time t3 while bringing the toes of the bucket 6 into contact with the ground at time t0 and closing the arm 5 and the bucket.

  The bucket angle (θ3) increases from time t0 to time t1 regardless of whether the excavation is normal excavation or deep excavation. Similarly, the excavation reaction force F increases from time t0 to time t1 to reach the value F1 regardless of whether the excavation is normal excavation or deep excavation.

  When it is determined that the bucket 6 is in contact with the ground at time t0 and it is determined that the excavation load may be excessive at time t1, the posture correction necessity determination unit 31 determines whether normal excavation or deep excavation is performed. .

  When the normal excavation is determined at time t1, the posture correction necessity determination unit 31 forcibly raises the boom 4 by forcibly extending the boom cylinder 7 regardless of the content of the operation input to the operation device 26. Let

  When the boom 4 is forcibly raised, the bucket angle (θ3) decreases from time t1 to time t2, as indicated by a broken line in FIG. Further, the excavation reaction force F decreases from time t1 to time t2, as indicated by a broken line in FIG. This is because the excavation depth becomes shallow.

  On the other hand, when the deep excavation is determined at time t1, the posture correction necessity determination unit 31 forcibly contracts the arm cylinder 8 to open the arm 5 regardless of the content of the operation input to the operation device 26. . This is because if the boom 4 is forcibly raised as in the case of normal excavation, the excavation reaction force F increases on the contrary. The alternate long and short dash line in FIG. 9B shows the transition of the excavation reaction force F when the boom 4 is forcibly raised when the deep excavation is determined. In this case, the excavation reaction force F increases from time t1 to time t11 and reaches a value F2. The value F2 is, for example, the value of the excavation reaction force F when the rear end of the excavator is lifted.

  When the arm 5 is forcibly opened, the bucket angle (θ3) decreases from time t1 to time t2, as indicated by the solid line in FIG. Further, the excavation reaction force F decreases from time t1 to time t2, as indicated by the solid line in FIG.

  If the boom 4 is raised by a predetermined boom angle during normal excavation, the posture correction necessity determination unit 31 stops the raising operation. Similarly, when the arm 5 is opened by a predetermined arm angle during deep excavation, the posture correction necessity determination unit 31 stops the opening operation.

  Thereafter, as excavation continues according to the combined operation of the operator, the bucket angle (θ3) increases from time t2 to time t3 regardless of whether the excavation is normal excavation or deep excavation. Similarly, the excavation reaction force F increases from time t2 to time t3 regardless of whether the excavation is normal excavation or deep excavation.

  With the above-described configuration, the controller 30 can determine with high accuracy whether the excavation load may become excessively high by deriving the current net excavation load with high accuracy. And when it determines with there exists a possibility that excavation load may become large too much, the attitude | position of a excavation attachment can be corrected automatically so that excavation load may become small. As a result, it is possible to prevent the excavation attachment from stopping due to an overload during the excavation operation, thereby realizing an efficient excavation operation.

  Further, the controller 30 can determine with high accuracy whether or not the excavation load may be excessively reduced by deriving the current net excavation load with high accuracy. And when it determines with there exists a possibility that excavation load may become small too much, the attitude | position of an excavation attachment can be corrected automatically so that excavation load may become large. As a result, the amount of excavation by one excavation operation can be prevented from becoming excessively small, and an efficient excavation operation can be realized.

  In this way, the controller 30 can automatically correct the attitude of the excavation attachment during the excavation operation so that the excavation reaction force has an appropriate magnitude. Therefore, accurate positioning control of the toe of the bucket 6 can be realized.

  Further, the controller 30 can change the correction contents of the posture of the excavation attachment between the normal excavation and the deep excavation. Therefore, it is possible to prevent the excavation reaction force from being increased by forcibly raising the boom 4 during deep excavation.

  Further, the controller 30 can calculate the excavation reaction force in consideration of not only the bucket excavation torque but also the boom excavation torque and the arm excavation torque. Therefore, the excavation reaction force can be derived with higher accuracy.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Can be added.

  For example, in the above-described embodiment, a cylinder pressure sensor is employed as an example of the excavation load information detection device, but other sensors such as a torque sensor may be employed as the excavation load information detection device.

  DESCRIPTION OF SYMBOLS 1 ... Lower traveling body 1A ... Left traveling hydraulic motor 1B ... Right traveling hydraulic motor 2 ... Turning mechanism 2A ... Turning hydraulic motor 3 ... Upper turning body 4 ... Boom 5 ... Arm 6 ... Bucket 7 ... Boom cylinder 8 ... Arm cylinder 9 ... Bucket cylinder 10 ... Cabin 11 ... Engine 11a ... Alternator 11b ... Starter 11c ... Water temperature sensor 14 ... Main pump 14a ... Regulator 14b ... Discharge pressure sensor 14c ... Oil temperature sensor 15 ... Pilot pumps 15a, 15b ... Pilot pressure sensor 16 ... High pressure Hydraulic line 17 ... Control valve 25, 25a ... Pilot line 26 ... Operating device 26A, 26B ... Bar 26C ... Pedal 30 ... Controller 30a ... Temporary storage unit 31 ... Posture correction necessity determination unit 40 ... Display device 41 ... Image display unit 42 ... Input unit 70 ... -Storage battery 72 ... Electrical equipment 74 ... Engine control device 75 ... Operation mode switching dial E1 ... Control valve M1 ... Attitude detection device M1a ... Boom angle sensor M1b ... Arm angle sensor M1c ... Bucket angle sensor S1, S11-S16 ... Cylinder pressure sensor

Claims (6)

A lower traveling body,
An upper swing body mounted on the lower traveling body;
A drilling attachment attached to the upper swing body;
An attitude detection device for detecting an attitude of the excavation attachment;
An excavation load information detection device for detecting information on excavation load;
A shovel having a control device for correcting the posture of the excavation attachment,
The control device opens the arm or bucket constituting the excavation attachment when it is determined that the excavation load during deep excavation is larger than a predetermined value based on the outputs of the attitude detection device and the excavation load information detection device Configured as
Excavator. The control device determines whether or not deep excavation is being performed based on at least a posture of a boom constituting the excavation attachment.
The excavator according to claim 1. The control device calculates the excavation reaction force based on the attitude of the excavation attachment and the excavation load, and determines whether the excavation load is greater than a predetermined value based on the calculated excavation reaction force;
The shovel according to claim 1 or 2. The control device determines whether the excavation load is greater than a predetermined value based on the boom cylinder pressure,
The shovel according to claim 1 or 2. The control device determines whether the excavation load is greater than a predetermined value based on the arm cylinder pressure,
The shovel according to claim 1 or 2. The control device determines whether the excavation load is greater than a predetermined value based on the inclination of the upper swing body,
The shovel according to claim 1 or 2.

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