Work machine

Abstract

A determination is made as to whether or not a plurality of actuators, which drive each of a plurality of structures of a work device, are in an overload state and in a stopped state, and when an actuator, which is in an overload state and in a stopped state, among the plurality of actuators is determined. The amount of pressure oil supplied to the selected actuator is corrected on the basis of the determination result. By appropriately controlling the operation of the actuator according to the speed of the working device and the load state of the actuator, the excavation operation can be performed more efficiently.

Description

Technical Field

[0001] The present invention relates to a working machine. Background Art

[0002] In a working machine having a front working machine (working device) such as a hydraulic excavator, an auxiliary system is proposed, which controls the action of an actuator according to the operation content input by an operator (hereinafter referred to as excavation control) in order to prevent the front working machine from stopping due to overload and to smoothly perform the excavation action when the front working machine performs an excavation action of sand and soil. As a prior art related to excavation control, for example, the technology disclosed in Patent Documents 1 and 2 is known.

[0003] Patent document 1 discloses an engineering machine that drives a boom, an arm and a bucket to perform excavation operations, the engineering machine comprising: a boom angle detector that detects the angle of the boom; an arm angle detector that detects the angle of the arm; a bucket angle detector that detects the angle of the bucket; a storage device that stores data related to the characteristics of sand to be excavated; and a control unit that controls the excavation action, the control unit calculates the excavation reaction force acting on the sand in the bucket based on the detected boom angle, the detected arm angle, the detected bucket angle and the sand characteristics stored in the storage device, and determines whether the calculated excavation reaction force is greater than a preset upper limit value to determine whether the excavation action should be corrected.

[0004] Patent document 2 discloses a backhoe excavator work vehicle, which is provided with a first sensor for detecting the upper and lower angles of the boom relative to the vehicle body and a second sensor for detecting the angle of the dipper arm relative to the boom, and a calculator for calculating the relative position of the front end of the dipper arm or bucket to the vehicle body based on information from these first and second sensors, and an output device for comparing the information from the calculator with information from a setter and issuing a signal to operate each actuator in such a manner that the front end of the dipper arm or bucket moves along a prescribed trajectory. The backhoe excavator work vehicle is provided with an overload determiner for determining that the front end of the dipper arm or bucket is overloaded based on the information from the calculator.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2011-252338

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 61-146929 Summary of the invention

[0009] Problems to be solved by the invention

[0010] In the prior art described in the above-mentioned patent document 1, based on the ground depth and the pre-input sand and soil characteristics, the force applied by the sand and soil to the front working machine during the excavation action (hereinafter referred to as the excavation reaction force) is obtained, and whether it is an overload state is determined by whether the excavation reaction force is greater than a predetermined upper limit value (hereinafter referred to as the maximum excavation force), and whether it is necessary to judge whether the excavation action needs to be corrected or the actuator action needs to be controlled.

[0011] However, the maximum excavation force that can be output by the hydraulic excavator depends on the maximum thrust of the cylinder, the geometrical configuration (geometrical structure, joint angle) of the working device, etc. Therefore, the maximum excavation force also changes according to the change of the posture of the working device. Therefore, if it is judged whether the excavation action needs to be corrected based on the predetermined maximum excavation force (upper limit value) as in the above-mentioned Patent Document 1, there is a case where it is judged that the excavation action needs to be corrected even though there is actually a margin up to the maximum excavation force.

[0012] In the prior art described in Patent Document 2, whether or not the bucket tip is in an overload state is determined based on whether or not the bucket tip has moved more than a predetermined distance within a predetermined time, that is, whether or not the bucket tip is in a stopped state.

[0013] However, in the work performed by the hydraulic excavator, the stop state of the front working machine is not necessarily caused only by the overload caused by the excavation reaction force. Therefore, in the above-mentioned Patent Document 2, for example, in the case of light excavation at a speed below a threshold such as in precision leveling work, there is a case where it is determined that the excavation action needs to be corrected.

[0014] The present invention has been made in view of the above, and an object of the present invention is to provide a working machine capable of performing excavation operation more efficiently by appropriately controlling the operation of an actuator according to the speed of a working device and the load state of the actuator.

[0015] Means for solving problems

[0016] The present application includes multiple means for solving the above-mentioned problems. As an example, a working machine is provided, comprising: a working device, which is composed of multiple structures; multiple actuators, which respectively drive the multiple structures of the working device; an overload detection device, which respectively detects the overload state of the multiple actuators; an angle / speed detection device, which respectively detects the movement angle and angular velocity of the multiple structures of the working device; an operating device, which operates the multiple actuators; and a control device, which controls the supply amount of pressure oil supplied to the multiple actuators according to the operation amount of the operating device, the control device determines whether the multiple actuators are in an overload state based on the detection result of the overload detection device, and determines whether the multiple actuators are in a stopped state based on the detection result of the angle / angular velocity detection device. When it is determined that an actuator among the multiple actuators is in an overload state and a stopped state, the supply amount of the pressure oil supplied to the selected actuator is corrected according to the determination result.

[0017] Effects of the Invention

[0018] According to the present invention, by appropriately controlling the actuator operation according to the speed of the working device and the load state of the actuator, it is possible to perform the excavation operation more efficiently. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a perspective view showing the appearance of a hydraulic excavator shown as an example of a working machine.

[0020] Figure 2 It is a functional block diagram that shows the processing functions of the controller together with the associated structure.

[0021] Figure 3 This is a functional block diagram that shows the processing functions of the auxiliary unit of the controller together with the related structure.

[0022] Figure 4 This is a flowchart showing the processing contents of the controller.

[0023] Figure 5 This is a diagram for explaining the basic concept of the command flow rate calculation based on the correction of the operation flow rate.

[0024] Figure 6 This is a diagram for explaining an example of a method of determining the assist direction when a single actuator satisfies condition A.

[0025] Figure 7 This is a diagram for explaining an example of a method of determining the assist direction when a single actuator satisfies condition A.

[0026] Figure 8This is a diagram for explaining an example of a method of determining the assist direction when a single actuator satisfies condition A.

[0027] Fig. 9 This is a diagram for explaining an example of a method of determining the assisting direction when a plurality of actuators satisfy condition A.

[0028] Fig.10 This is a diagram for explaining an example of a method of determining the assisting direction when a plurality of actuators satisfy condition A.

[0029] Fig.11 This is a diagram for explaining an example of a method of determining the assisting direction when a plurality of actuators satisfy condition A.

[0030] Fig.12 This is a diagram for explaining an example of a method of determining the assisting direction when a plurality of actuators satisfy condition A.

[0031] Fig.13 This is a functional block diagram showing the processing functions of the auxiliary unit of the controller according to the second embodiment together with related structures.

[0032] Fig.14 This is a diagram showing an example of a norm calculation table that defines the relationship between the elapsed time and the norm when the arm cylinder satisfies condition A.

[0033] Fig.15 This is a diagram showing a state of a target velocity vector of the claw tip of the bucket after correction of the operation flow rate when the norm calculation table is applied. DETAILED DESCRIPTION

[0034] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, a hydraulic excavator is described as an example of a working machine having a front working device (working device), but the present invention can also be applied to other working machines having a front working device.

[0035] In the following description, when there are a plurality of identical components, a letter may be added to the end of a symbol (number), but the letter may be omitted and the plurality of components may be collectively labeled. That is, for example, when there are three angle / angular velocity detection devices 20a, 20b, and 20c, they may be collectively labeled as the angle / angular velocity detection device 20. In addition, for the sake of simplicity, the illustration of signal lines and the like whose connection relationship is clearly defined by the description may be omitted.

[0036] <First Embodiment>

[0037] Reference Figures 1 to 12 A first embodiment of the present invention will be described.

[0038] Figure 1 It is a perspective view showing the appearance of a hydraulic excavator shown as an example of a working machine in the present embodiment.

[0039] exist Figure 1 In the figure, the hydraulic excavator 1 comprises: a lower traveling body 1C; an upper revolving body 1B which is rotatably mounted on the lower traveling body 1C via a revolving device 4 and constitutes a vehicle body together with the lower traveling body 1C; and a front working device 1A which is mounted on the front of the upper revolving body 1B and constitutes a working device.

[0040] The front working machine 1A is roughly composed of the following parts: a boom 8 as a structure that can be mounted on the front part of the upper rotating body 1B so as to be rotatable in the up-down direction, an arm 9 as a structure that can be mounted on the front end (rear section) of the boom 8 so as to be rotatable in the up-down direction, a bucket 10 as a structure that can be mounted on the front end (rear section) of the arm 9 so as to be rotatable in the up-down direction, a bucket link 13 that can be rotatably mounted on the arm 9 and the bucket 10, a boom cylinder 5 connected to the upper rotating body 1B and the boom 8 and changing the rotation angle of the boom 8 relative to the upper rotating body 1B by driving the boom 8 in the up-down direction relative to the upper rotating body 1B, an arm cylinder 6 connected to the boom 8 and the arm 9 and changing the rotation angle of the arm 9 relative to the boom 8 by driving the arm 9 in the up-down direction relative to the boom 8, and a bucket cylinder 7 connected to the arm 9 and the bucket link 13 and changing the rotation angle of the bucket 10 relative to the arm 9 via the bucket link 13. The structure has a structure in which an arm 9 is provided at a front stage of a bucket 10 as a structure, and a boom 8 is provided at a front stage of the arm 9 .

[0041] The lower traveling body 1C has left and right traveling devices 3 of crawler type (in Figure 1 Only the left travel device 3 is shown in the figure, and the left and right travel devices 3 are composed of left and right travel motors 3a (in Figure 1 Only the travel motor 3a on the left side is shown in the figure, and the hydraulic excavator 1 can be moved to a desired position by driving.

[0042] The revolving device 4 includes a revolving motor 11 for changing the rotation angles of the lower traveling body 1C and the upper revolving body 1B.

[0043] A cab 12 forming a driver's cabin is arranged beside the front working machine 1A in front of the upper revolving body 1B. A controller 22 (control device) for controlling the overall movement of the hydraulic excavator 1 is arranged behind the driver's seat where the operator sits in the cab 12. In addition, operating devices 2 are arranged on the left and right sides in front of the driver's seat in the cab 12, and the operating devices 2 generate operating signals indicating the movement (speed and direction) of the boom 8, the arm 9, the bucket 10 and the upper revolving body 1B through the operation of the operator. In addition, an operating device that generates operating signals indicating the movement (speed and direction) of the left and right travel devices 3 is also arranged in front of the driver's seat.

[0044] The boom 8, the arm 9, and the bucket 10 are provided with a boom angle / angular velocity detection device 20a, an arm angle / angular velocity detection device 20b, and a bucket angle / angular velocity detection device 20c, which detect the angle (action angle) relative to the horizontal plane and the angular velocity based on the action, respectively. In addition, the bucket angle / angular velocity detection device 20c may be provided on the bucket link 13 instead of the bucket 10. Hereinafter, the boom angle / angular velocity detection device 20a, the arm angle / angular velocity detection device 20b, and the bucket angle / angular velocity detection device 20c may be collectively referred to as the angle / angular velocity detection device 20.

[0045] The angle / angular velocity detection device 20 is, for example, an IMU (Inertial Measurement Unit). However, the angle / angular velocity detection device 20 may be any device that can measure / calculate the angle and angular velocity. For example, a device that directly measures the angle / angular velocity, such as a potentiometer / gyroscope device, a device that performs numerical differentiation / integration calculations on the measured angular velocity, or a combination thereof may be used.

[0046] A pressure sensor 25a for detecting the pressure on the bottom side (bottom pressure) and the pressure on the rod side (rod pressure) of the boom cylinder 5 is provided in the boom cylinder 5. In addition, a pressure sensor 25b for detecting the pressure on the bottom side (bottom pressure) and the pressure on the rod side (rod pressure) of the boom cylinder 6 is provided in the arm cylinder 6. Similarly, a pressure sensor 25c for detecting the pressure on the bottom side (bottom pressure) and the pressure on the rod side (rod pressure) of the bucket cylinder 7 is provided in the bucket cylinder 7.

[0047] The pressure sensors 25a, 25b, 25c, together with a functional unit (not shown) provided in the controller 22, constitute a boom overload detection device 61a, an arm overload detection device 61b, and a bucket overload detection device 61c, which detect the overload state of the boom cylinder 5, the arm cylinder 6, and the bucket cylinder 7, respectively, based on the thrust of the boom cylinder 5, the arm cylinder 6, and the bucket cylinder 7 and the pressure resistance specification as the equipment performance of these cylinders, or the limit value (pressure) on the hydraulic circuit driving these cylinders. Hereinafter, the boom overload detection device 61a, the arm overload detection device 61b, and the bucket overload detection device 61c are sometimes collectively referred to as the overload detection device 61.

[0048] The overload state of the boom cylinder 5, the arm cylinder 6 and the bucket cylinder 7 is determined by the overload detection device 61 according to the following (Formula 1) and (Formula 2). When the above (Formula 1) or (Formula 2) is satisfied, it is determined to be an overload state.

[0049] P i_btm ≥P sat_i …(Formula 1)

[0050] P i_rod ≥P sat_i …(Formula 2)

[0051] In the above (Formula 1) and (Formula 2), P i_btm , P i_rod represents the measured pressure of the pressure sensor 25, P sat_i represents the pressure resistance specification, i represents which of the boom cylinder 5, the arm cylinder 6 and the bucket cylinder 7 is the target, for example, when P is satisfied bm_btm ≥P sat_bm (Refer to the above (Formula 1)) or P bm_rod ≥P sat_bm (Refer to the above (Formula 2)), it is determined that the bottom side of the boom cylinder 5 is in an overload state. In addition, when a relief valve (so-called overload relief valve) connected to the bottom side or the rod side is provided in the hydraulic circuit structure, the pressure resistance specification used in the calculation of the overload detection device 61 may be the lower one of the pressure resistance specification and the limit value on the hydraulic circuit, that is, the relief valve setting pressure.

[0052] Figure 2 It is a functional block diagram that shows the processing functions of the controller together with the associated structure.

[0053] exist Figure 2In the controller 22, there are: an operation flow calculation unit 202 for calculating the supply amount of pressure oil to be supplied to the boom cylinder 5, the arm cylinder 6 and the bucket cylinder 7, that is, the operation flow, according to the operation state (operation direction, operation amount) of the operation device 2; a boom 8, arm 9, bucket 10 and other respective structures that cause the boom cylinder 5, the arm cylinder 6, and the bucket cylinder 7 (hereinafter sometimes collectively referred to as actuators) to move according to the angular velocity detected by the angle / angular velocity detection device 20; a stop state calculation unit 203 for determining whether the structure in the front section (for example, the boom 8 relative to the arm 9) is in a stop state; and an auxiliary unit 201 for calculating and outputting the command flow of the actuators 5, 6, 7 according to the operation flow from the operation flow calculation unit 202, the overload state from the overload detection device 61 (information indicating whether it is an overload state), the angle from the angle / angular velocity detection device 20, and the stop state from the stop state calculation unit 203 (information indicating whether it is a stop state).

[0054] The operation flow calculated by the operation flow calculation unit 202 may include information related to the operation flow, and the operation flow may be instructed from another external system such as a remote operation device or an automatic system on a server, for example.

[0055] Figure 3 This is a functional block diagram that shows the processing functions of the auxiliary unit of the controller together with the related structure.

[0056] exist Figure 3 In the figure, the auxiliary unit 201 has: an upward direction specifying unit 301, a claw tip position calculating unit 302, a fully overloaded movable direction calculating unit 303, a corrected actuator calculating unit 304, an overloaded movable direction calculating unit 305, an movable direction determining unit 306 and an instruction flow calculating unit 307.

[0057] The upward direction designation unit 301 designates the opposite direction of the gravity vector (vertical upward direction) by, for example, a prior input in the operating device 2. Alternatively, for example, an inertial measurement unit (IMU) may be disposed on the upper rotating body 1B instead of a prior input by the operating device 2, and the direction corresponding to the upward direction of the upper rotating body 1B may be designated by automatic input based on the detection result thereof.

[0058] The claw tip position calculation unit 302 calculates the position coordinates of the claw tip of the bucket 10 in the vehicle body coordinate system based on the detection result (angle) from the angle / angular velocity detection device 20 .

[0059] The fully overloaded movable direction calculation unit 303 calculates the full overloaded target speed vector representing the target direction and target speed of the claw tip movement of the bucket 10 at full overload based on the designated content (vertical upward direction) from the upper direction designation unit 301 and the calculation result (claw tip coordinates) from the claw tip position calculation unit 302.

[0060] The correction actuator operation unit 304 determines the actuators 5, 6, and 7 for correcting the supply amount of pressure oil by correcting the operating flow based on the operation result from the stop state operation unit 203 (information indicating whether the structure and the structure in the previous section are in the stop state) and the detection result from the overload detection device 61 (information indicating whether it is overloaded).

[0061] The overloaded movable direction calculation unit 305 calculates the overloaded target speed vector representing the target direction and target speed of the claw tip movement of the bucket 10 when overloaded, based on the detection result (angle) from the angle / angular velocity detection device 20 and the calculation result (corrected actuator information) from the correction actuator calculation unit 304.

[0062] The action direction determination unit 306 calculates the target speed vector of the claw tip of the bucket 10 based on the calculation result from the full overload action direction calculation unit 303 (full overload target speed vector), the calculation result from the overload action direction calculation unit 305 (overload target speed vector), and the calculation result from the correction actuator calculation unit (corrected actuator information).

[0063] The command flow rate calculation unit 307 calculates and determines the command flow rate to the actuators 5, 6, and 7 based on the calculation result (target speed vector) from the motion direction determination unit 306, the calculation result (operation flow rate) from the operation flow rate calculation unit 202, and the detection result (angle) from the angle / angular velocity detection device 20, and outputs it to the actuators 5, 6, and 7. Specifically, the target speed vector of the claw tip of the bucket 10 from the motion direction determination unit 306 is converted into the target speed of the cylinder using the Jacobian matrix or the like, thereby calculating the command flow rate.

[0064] Figure 4 This is a flowchart showing the processing contents of the controller.

[0065] exist Figure 4 In step S100, the controller 22 first calculates the actuators 5, 6, and 7 to satisfy the condition (condition A) that the actuators 5, 6, and 7 are in an overload state and the structures (boom 8, arm 9, bucket 10) corresponding to the actuators 5, 6, and 7 are in a stopped state.

[0066] Next, it is determined whether there is no actuator satisfying condition A (step S110). If the determination result is yes, that is, if all actuators (boom cylinder 5, arm cylinder 6, and bucket cylinder 7) do not satisfy condition A, the operation result (operation flow) of the operation flow calculation unit 202 is not corrected and is output as a command flow to the actuators 5, 6, and 7 (step S111), and the processing is terminated. In the processing of step S110, if there is no actuator satisfying condition A, the operation flow is not corrected (refer to step S111), thereby achieving efficient processing.

[0067] In addition, when the determination result in step S110 is no, that is, when it is determined that there is an actuator that satisfies condition A, it is determined whether the actuator that is determined to satisfy condition A continues to satisfy condition A for a period of time (prescribed time) or longer (in other words, whether the prescribed time has passed since the actuator satisfied condition A) (step S120). The processing of step S120 is performed in order to interrupt the correction of the operating flow rate and notify (display) the operator if the prescribed time has passed since the actuator satisfied condition A (yes), because the state of the actuator has not been improved even by the correction of the operating flow rate, thereby urging the operator to confirm and respond to the current situation, thereby achieving efficient processing.

[0068] If the result of determination in step S120 is yes, that is, if it is determined that condition A is continuously satisfied for a period longer than a predetermined time (that is, a predetermined time has passed since the actuator satisfied condition A), the calculation result (operation flow rate) of the operation flow calculation unit 202 is not corrected and is output as a command flow rate to the actuators 5, 6, and 7, and the meaning of interrupting the correction of the operation flow rate is displayed on the display device 23 to notify the operator (step S121), and the processing is terminated. In addition, the resumption of the processing of the next step S100 after the interruption of the processing of step S121 is considered to be triggered by the fact that all the operation flows once become 0 (zero) (making the operating device neutral), the locking lever is lifted, the key is disconnected, etc.

[0069] In addition, when the judgment result in step S120 is negative, that is, when the actuator determined to satisfy condition A has not satisfied condition A for more than a specified time (that is, the specified time has not passed since the actuator satisfied condition A), it is determined whether all actuators satisfy condition A (step S130).

[0070] If the result of determination in step S130 is yes, that is, if it is determined that all actuators satisfy condition A, all actuators are selected as actuators for correcting the operating flow rate, and the command flow rate after correcting the operating flow rate of all actuators is calculated and output to actuators 5, 6, and 7 (step S131), and the processing ends. In addition, if the result of determination in step S130 is no, the process proceeds to step S140 as described later, and an actuator that does not satisfy condition A is selected as an actuator to be corrected, and the operating flow rate of the actuator is corrected, and the processing ends.

[0071] Figure 5 This is a diagram for explaining the basic concept of the command flow rate calculation based on the correction of the operation flow rate.

[0072] exist Figure 5 In the example, the position x of the claw tip of the bucket 10 at a certain time n is represented by the claw tip position x n Indicates that it will reach the claw tip position x n The position x of the claw tip of the bucket 10 at the previous time n-1 is represented by the claw tip position x n-1 It means that the direction that the claw tip of the bucket 10 has passed at time n is represented by the vector X=x n-1 -x n The vertical upward direction specified by the upward direction specifying unit 301 is represented by a vector v. In addition, the claw tip position x n 、x n-1 The subscript n defines a variable representing the clock scale time of the controller 22, which varies as ..., n-1, n, n+1, ... (n is a positive integer), but as long as it can refer to the past claw tip position x, for example, it can also be traced back to a predetermined time or distance.

[0073] like Figure 5 As shown, in Figure 4 In step S131, for example, the claw tip position x of the bucket 10 n The direction of travel (vector x) becomes the reverse direction (towards the position x that has already passed n-1 and in the direction opposite to the direction of vector X) to the vertical upward direction (vector v) specified by the upward direction specifying unit 301 (that is, Figure 5 Specifically, one of the purposes of calculating the command flow rate based on the correction of the operation flow rate is to operate the front working machine 1A in a manner that reduces the load of each actuator 5, 6, 7 (in a manner that eliminates the overload state), so that the movement direction of the point of force of the front working machine 1A relative to the excavation object such as the ground (here, the claw tip position of the bucket 10) becomes the direction in which the excavation is completed and there is no sand and soil, that is, Figure 5In addition, the command flow rate may be calculated by correcting the operation flow rates of the actuators 5, 6, and 7 so that the moving direction of the claw tip position of the bucket 10 becomes the direction in which the excavation depth becomes shallower, that is, from the vertical direction to the vertical upward direction relative to the ground surface of the excavation object, and calculating the command flow rate.

[0074] exist Figure 4 When the result of determination in step S130 is negative, that is, when there is an actuator that does not satisfy condition A, the operating flow is corrected for the actuator that does not satisfy condition A to calculate the command flow, and the command flow is output to the actuators 5, 6, and 7 (step S140), and the processing ends. Specifically, when there is an actuator that does not satisfy condition A, that is, when at least one of the boom cylinder 5, the arm cylinder 6, and the bucket cylinder 7 does not satisfy condition A, for the actuator that satisfies condition A, the operating flow that is the calculation result of the operating flow calculation unit 202 is output to the actuator as the command flow. In addition, for the actuator that does not satisfy condition A, the operating flow is corrected and the command flow is calculated in such a way that the direction of travel of the claw tip position of the bucket of the actuator that does not satisfy condition A becomes a direction perpendicular to the direction of travel of the claw tip position of the actuator that satisfies condition A, and the command flow is output to the actuator that does not satisfy condition A.

[0075] Here, Figure 4 The processing of step S140, that is, the method of determining the moving direction (auxiliary direction) of the claw tip position of the bucket 10 in the calculation of the command flow rate corrected by the operation flow rate is described in detail. If the front working machine 1A illustrated in this embodiment is considered, as the states that step S140 can take, the case where multiple (two) actuators satisfy the condition A and the case where a single (one) actuator satisfies the condition A are considered.

[0076] Figure 6 to Figure 8 This is a diagram for explaining an example of a method of determining the assist direction when a single actuator satisfies the condition A, and illustrates a case where only the boom cylinder satisfies the condition A. Figure 6 to Figure 8 BM schematically represents a boom 8 , AM schematically represents an arm 9 , and BK schematically represents a bucket 10 .

[0077] The movement of the claw tip of the bucket 10 in the front working machine 1A by a certain actuator is a movement around an axis caused by the actuator rotating it. Figure 6 As shown, when a single actuator satisfies condition A, the target velocity vector of the claw tip of the bucket 10 based on the actuator satisfying condition A becomes a vector connecting the rotation axis of the front side of the structure that causes the action of the actuator satisfying condition A (the base end side of the boom 8 in the case of the boom 8) and the claw tip of the bucket 10.

[0078] In this case, other actuators that do not satisfy condition A assist so that the claw tip of bucket 10 moves in a direction that is closest to perpendicular to the target velocity vector of the claw tip of bucket 10 by the actuator that satisfies condition A.

[0079] like Figure 6 As shown, when only the boom cylinder 5 satisfies condition A, there are two solutions as the direction closest to verticality, which is the direction of +90 (deg) and the direction of -90 (deg) relative to the above-mentioned vector (see Figure 6 ). As to which of the two solutions to select, there are two selection methods, for example, as follows.

[0080] As a first selection method (hereinafter referred to as selection method 1), consider the case where selection is performed in a manner of intervening in a predetermined direction. In this case, for each actuator (boom 8, arm 9, bucket 10) that satisfies condition A, it is preset to select either +90 (deg) or -90 (deg).

[0081] As a second selection method (hereinafter referred to as selection method 2), a case where selection is performed in a manner that matches the current motion direction is considered. In this case, for example, when the boom cylinder 5 satisfies condition A, the angular velocity of the intervening boom 9 and bucket 10 is measured, and the directional velocity vector of the claw tip based on the angular velocity of the boom 9 and bucket 10 is calculated (see Figure 7 ), select the solution with the smaller angle with the velocity vector in the direction of the claw tip (refer to Figure 8 ) By selecting the intervention direction using the selection method 2, the change relative to the current action becomes small, and assistance that is less likely to cause discomfort to the operator can be performed.

[0082] Furthermore, selection method 1 and selection method 2 can also be similarly applied to a case where the individual actuator satisfying condition A is the arm 9 or the bucket 10 .

[0083] Figures 9 to 12 This is a diagram for explaining an example of a method of determining an assist direction when a plurality of actuators satisfy condition A, and illustrates a case where a boom cylinder and an arm cylinder satisfy condition A. Figures 9 to 12 BM schematically represents a boom 8 , AM schematically represents an arm 9 , and BK schematically represents a bucket 10 .

[0084] like Fig. 9 As shown, when a plurality of actuators satisfy condition A, a target velocity vector of the claw tip of the bucket 10 based on the actuator satisfying condition A is obtained for each of the plurality of actuators satisfying condition A.

[0085] Specifically, if Fig. 9 as well as Fig.10 As shown, there is a movement direction v based on the boom cylinder 5 BM and the direction v based on the boom cylinder 6 AM These two motion directions are assisted by other actuators that do not satisfy condition A so that the claw tip of the bucket 10 moves in a direction in which the sum of the angles formed by these two vectors and the velocity vector at which the claw tip can be moved by the remaining actuator (here, the bucket cylinder 7) is minimized.

[0086] When the boom cylinder 5 and the arm cylinder 6 satisfy the condition A, the velocity vector in the direction in which the claw tip can be moved by the bucket cylinder 7 has a vector v in the positive direction (movable direction (1)). BK1 and the vector v in the negative direction (the direction in which movement is possible (2)) BK2 These two (ref. Fig.10 ).

[0087] like Fig.11 and Fig.12 As shown, the angle between the vectors is θ BM1 ,θ BM2 ,θ AM1 ,θ AM2 The angle between them is obtained by the following (Equation 3) to (Equation 6) using the function f obtained by the definition of the inner product of vectors and the cosine theorem.

[0088] θ BM1 =f(v BK1 , v BM )…(Formula 3)

[0089] θ BM2 =f(v BK2 , v BM )…(Formula 4)

[0090] θ AM1 =f(v BK1 , v AM )…(Formula 5)

[0091] θ AM2 =f(v BK2 , v AM )…(Formula 6)

[0092] The auxiliary operation is performed by setting a target speed vector according to the relationship between the angles formed.

[0093] Specifically, when the following (Equation 7) is satisfied, the vector v BK1 Set as the target velocity vector.

[0094] θ BM1 +θ AM1 <θ BM2 +θAM2 …(Formula 7)

[0095] In addition, when the following (Equation 8) is satisfied, the vector v BK2 Set as the target velocity vector.

[0096] θ BM1 +θ AM1 >θ BM2 +θ AM2 …(Equation 8)

[0097] In addition, when the following (Equation 9) is satisfied, it is pre-set that the vector v BK1 and vector v BK2 Which one of them is used as the target velocity vector, and the set vector is used as the target velocity vector.

[0098] θ BM1 +θ AM1 =θ BM2 +θ AM2 …(Formula 9)

[0099] The above-described method of setting the target speed vector can also be similarly applied to a case where the plurality of actuators satisfying the condition A are the boom 8 and the bucket 10 , or the arm 9 and the bucket 10 .

[0100] In the present embodiment constructed as described above, based on the detection result of the angle / angular velocity detection device 20, the stop state of the front working machine (working device) 1A based on the overload state can be appropriately determined, and it can be appropriately determined whether correction is required. By correcting the operating flow of the actuator that is different from the actuator in the overload state and the stop state, the overload state can be eliminated while maintaining the excavation force as much as possible, and the excavation action can be performed more efficiently.

[0101] <Second Embodiment>

[0102] Reference Figure 13 to Figure 1 6 A second embodiment of the present invention will be described. In this embodiment, the same components as those of the first embodiment will be described using the same reference numerals, and description thereof will be appropriately omitted.

[0103] Fig.13 This is a functional block diagram showing the processing functions of the auxiliary unit of the controller according to this embodiment together with the associated configuration.

[0104] exist Fig.13In the figure, the auxiliary unit 201A has: an upward direction specifying unit 301, a claw tip position calculating unit 302, a movable direction calculating unit 303 when fully overloaded, a corrected actuator calculating unit 304, an movable direction calculating unit 305 when overloaded, a time norm relationship recording unit 701, an action direction determining unit 306A and an instruction flow calculating unit 307.

[0105] The upward direction designation unit 301 designates the opposite direction of the gravity vector (vertical upward direction) by, for example, a prior input in the operating device 2. Alternatively, for example, an inertial measurement unit (IMU) may be provided on the upper rotating body 1B instead of a prior input in the operating device 2, and the direction corresponding to the upward direction of the upper rotating body 1B may be designated by automatic input based on the detection result thereof.

[0106] The claw tip position calculation unit 302 calculates the position coordinates of the claw tip of the bucket 10 in the vehicle body coordinate system based on the detection result (angle) from the angle / angular velocity detection device 20 .

[0107] The fully overloaded movable direction calculation unit 303 calculates the full overloaded target speed vector representing the target direction and target speed of the claw tip movement of the bucket 10 at full overload based on the designated content (vertical upward direction) from the upper direction designation unit 301 and the calculation result (claw tip coordinates) from the claw tip position calculation unit 302.

[0108] The correction actuator calculation unit 304 determines the actuators 5, 6, 7 for correcting the operating flow rate based on the calculation result (information indicating whether it is in the stopped state) from the stopped state calculation unit 203 and the detection result (information indicating whether it is overloaded) from the overload detection device 61.

[0109] The overloaded movable direction calculation unit 305 calculates the overloaded target speed vector representing the target direction and target speed of the claw tip movement of the bucket 10 when overloaded, based on the detection result (angle) from the angle / angular velocity detection device 20 and the calculation result (information of the actuator that corrects the operating flow) from the correction actuator calculation unit 304.

[0110] The time-norm relationship recording unit 701 records a norm calculation table that predetermines the relationship between the elapsed time from when the condition (condition A) of the overload state and the stopped state is satisfied and the norm (magnitude) of the target velocity vector of the claw tip of the bucket 10 .

[0111] Fig.14 This is a diagram showing an example of a norm calculation table that defines the relationship between the elapsed time and the norm when the arm cylinder satisfies condition A.

[0112] like Fig.14As shown in FIG. 1 , in the norm calculation table, the norm of the target velocity vector of the claw tip of the bucket 10 is set to increase as the elapsed time (t) from when the condition A is satisfied increases. For example, at time t n When , the norm of the target velocity vector is set to k n , after the time increases to become time t m When the norm of the target velocity vector also increases and becomes k m In addition, Fig.14 , the example shows a case where the norm of the target speed increases in proportion to the increase in the elapsed time, but the norm calculation table only needs to be set so that the norm of the target speed increases as the elapsed time increases. For example, a norm calculation table representing a non-linear (proportional) curve relationship can also be set.

[0113] The action direction determination unit 306A calculates the target speed vector of the claw tip of the bucket 10 based on the calculation result from the full overload action direction calculation unit 303 (target speed vector at full overload), the calculation result from the overload action direction calculation unit 305 (target speed vector at overload), the calculation result from the correction actuator calculation unit (information of the actuator for correcting the operating flow), and the norm calculation table of the time norm relationship recording unit 701.

[0114] In the motion direction determination unit 306A, the maintenance time after the actuator determined as the correction target by the correction actuator calculation unit 304 becomes the operating state (true state) is recorded, and the norm of the target velocity vector of the claw tip of the bucket 10 is increased according to the elapsed time based on the norm calculation table. In addition, when the target actuator becomes the non-operating state (false state), the count of the maintenance time is reset.

[0115] Fig.15 This is a diagram showing a state of a target velocity vector of the claw tip of the bucket after correction of the operation flow rate when the norm calculation table is applied. Fig.15 BM schematically represents a boom 8 , AM schematically represents an arm 9 , and BK schematically represents a bucket 10 .

[0116] like Fig.15 As shown, the target speed vector is set so that the norm tm is larger when the time has passed than the norm kn when the time has passed tn. That is, it can be said that the magnitude of the target speed vector after correction of the operating flow rate of the actuator increases according to the elapsed time from the overload state and the stop state.

[0117] The command flow rate calculation unit 307A calculates and determines the command flow rate to the actuators 5, 6, and 7 based on the calculation result (target speed vector) from the motion direction determination unit 306, the calculation result (operation flow rate) from the operation flow rate calculation unit 202, and the detection result (angle) from the angle / angular velocity detection device 20, and outputs it to the actuators 5, 6, and 7. Specifically, the target speed vector of the claw tip of the bucket 10 from the motion direction determination unit 306 is converted into the target speed of the cylinder using the Jacobian matrix or the like, thereby calculating the command flow rate.

[0118] The other structures are the same as those of the first embodiment.

[0119] In the present embodiment configured as above, the same effects as those of the first embodiment can be obtained.

[0120] In addition, the supply amount (operation flow rate) of the pressure oil to the actuator is corrected to be larger according to the elapsed time since the condition A of the overload state and the stop state is satisfied, so the stop state of the structure caused by the overload can be eliminated more quickly.

[0121] <Notes>

[0122] In addition, the present invention is not limited to the above-mentioned embodiments, and includes various modifications and combinations within the scope of the present invention. In addition, the present invention is not limited to all the structures described in the above-mentioned embodiments, and also includes a structure in which a part of the structure is deleted. In addition, the above-mentioned structures, functions, etc. can also be implemented by, for example, designing a part or all of them in an integrated circuit. In addition, the above-mentioned structures, functions, etc. can also be implemented by software by interpreting and executing a program that implements each function through a processor.

[0123] Explanation of symbols

[0124] 1…Hydraulic excavator, 1A…Front working machine (working device), 1B…Upper swing body, 1C…Lower travel body, 2…Operating device, 3…Travel device, 3a…Travel motor, 4…Swing device, 5…Boom cylinder, 6…Arm cylinder, 7…Bucket cylinder, 8…Boom, 9…Arm, 10…Bucket, 11…Swing motor, 12…Operating cab, 13…Bucket connecting rod, 20a, 20b, 20c…Angle / angular velocity detection device, 22…Controller, 23…Display device, 25a, 25b, 25c…Pressure sensor Sensor, 61a, 61b, 61c...overload detection device, 201, 201A...auxiliary unit, 202...operation flow calculation unit, 203...stop state calculation unit, 301...upper direction designation unit, 302...claw position calculation unit, 303...full overload actionable direction calculation unit, 304...correction actuator calculation unit, 305...overload actionable direction calculation unit, 306, 306A...action direction determination unit, 307, 307A...command flow calculation unit, 701...time norm relationship recording unit.

Claims

1. A working machine having: A working device, which is composed of a plurality of structures; A plurality of actuators, which respectively drive the plurality of structures of the working device; an overload detection device for detecting the overload status of the plurality of actuators respectively; An angle / speed detection device, which detects the action angle and angular speed of the plurality of structures of the working device respectively; an operating device for operating the plurality of said actuators; as well as a control device for controlling the supply amount of the pressure oil supplied to the plurality of the actuators according to the operation amount of the operating device, The working machine is characterized in that The control device determines whether the multiple actuators are in an overload state based on the detection result of the overload detection device, and determines whether the multiple actuators are in a stopped state based on the detection result of the angle / angular velocity detection device. When it is determined that an actuator among the multiple actuators is in an overload state and a stopped state, the supply amount of the pressure oil supplied to the selected actuator is corrected according to the determination result.

2. The working machine according to claim 1, characterized in that: When the control device determines that some of the plurality of actuators are in an overloaded state and in a stopped state, the control device corrects the supply amount of the pressure oil to an actuator other than the overloaded and stopped actuator.

3. The working machine according to claim 1, characterized in that: The control device corrects the amount of the pressure oil supplied to all the actuators when it is determined that all of the plurality of actuators are in an overloaded state and in a stopped state.

4. The working machine according to claim 2 or 3, characterized in that: When the control device determines that there is an actuator in an overloaded and stopped state, if a time period in the overloaded and stopped state is shorter than a predetermined time period, the control device corrects a supply amount of the pressure oil to the actuator.

5. The working machine according to claim 1, characterized in that: The velocity vector of the front end of the working device after the control device corrects the supply amount of the pressure oil supplied to the actuator is close to a direction perpendicular to the direction vector of the front end of the working device moving by the actuator in an overloaded and stopped state.

6. The working machine according to claim 1, characterized in that: The control device corrects the supply amount of the pressure oil supplied to the actuator so that the magnitude of the velocity vector of the front end of the working device after the correction of the supply amount of the pressure oil supplied to the actuator increases according to the elapsed time after the actuator is in an overload state and becomes a stopped state.

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