JP2021152275A - Working machine - Google Patents

Abstract

To provide a working machine allowing information of parameter on its driven members when exchanging the driven members configuring the working machine.SOLUTION: A bucket 10 will be rotated by a cylinder 13 around a pin 10a as a center when exchanging the buckets 10 of a working device 3. Formula (Tc=Fw×Lw) shall be established between a moment Tc created with thrust Fb of the cylinder 13, force Fw of dead weight of the bucket 10 to a position of the center of gravity, and a moment arm length Lw by the Fw, and Formula (LW=L cog*cos(θ cog+γ)) shall be established between a distance Lcog from an original point O to the position of the center of gravity, an angle θ cog between a line from the original point O to a tip of a bucket nail and a line from the original point to the position of the center of gravity, and a bucket rotation angle γ. L cog and θ cog are obtained through previously inputting Fw, sequentially measuring γ by sequentially calculating Lw while rotation of the bucket 10, and determining a position of the center of gravity of the bucket 10 by determining γ where Lw becomes the maximum.SELECTED DRAWING: Figure 12

Description

The present invention relates to a work machine provided with a work device.

This type of work machine, for example, a hydraulic excavator, is provided with an upper swing body that can be swiveled on a lower traveling body that can be traveled by a crawler, and an articulated work device is provided at the front portion of the upper swivel body. Since the work device changes its posture according to the work content in a state where it projects forward like a cantilever from the upper swing body, the center of gravity of the vehicle also changes constantly. If an unreasonable operation is performed, the work machine may become unbalanced and fall, so the operator during work always pays attention to the stability of the vehicle body and immediately stabilizes when there is a possibility of falling. It is necessary to operate in the direction.

In order to reduce the burden on the operator during such work, for example, the hydraulic excavator described in Patent Document 1 notifies the operator based on the stability evaluation of the vehicle body using ZMP (Zero Moment Point). .. ZMP is the position of the dynamic center of gravity of the vehicle body, and when ZMP is included in the warning area on the periphery of the support polygon obtained from the grounding point of the hydraulic excavator, it issues a fall warning as a possibility of falling. ..

On the other hand, in Patent Document 2, a jib is connected to the tip of the main boom so that it can be moved up and down, an arm is connected to the tip of the jib so that it can be moved up and down, and a plurality of types of work tools are attached to the tip of the arm according to the work content. A dismantling work machine that can be arbitrarily connected is disclosed. Considering that the stability of the vehicle body and the allowable elevation angle of the jib differ depending on the weight of the work tool and the position of the center of gravity, the weight and the position of the center of gravity are input to the input device as the parameters of the work tool, and the upper limit of the depression / elevation angle is reached. When the angle is calculated and the depression / elevation angle exceeds the upper limit angle during work, the stability of the vehicle body is ensured by limiting the depression / elevation movement of the jib.

International Publication No. 2011/148946 JP 2016-169473

In the technique of Patent Document 1, parameters such as the weight and the position of the center of gravity of each part of the hydraulic excavator are required as one of the information for calculating ZMP, and the boom, arm, and work tool which are driven members constituting the work device. When such items are replaced according to the work content, it is necessary to update the parameters of the driven member after the replacement. As a countermeasure, it is conceivable to input each parameter by an input device as in the technique of Patent Document 2, but in order to obtain information on the parameter to be input, the weight and the position of the center of gravity of a single driven member are actually obtained. In addition to the fact that the driven member is a heavy object, it takes time and effort to perform the measurement work. For this reason, there is a problem that the replacement work of the driven member as a whole including the measurement work becomes very complicated.

The present invention has been made to solve such a problem, and an object of the present invention is to simplify information on parameters related to the driven member when the driven member constituting the working device is replaced. It is an object of the present invention to provide a work machine which can be acquired by a procedure and can easily and quickly carry out replacement work of a driven member as a whole.

In order to achieve the above object, the working machine of the present invention is an articulated work in which a plurality of driven members are connected to each other via a rotation shaft and each of the driven members can be rotated by driving an actuator. In a work machine that constitutes a device and is provided with the work device on a vehicle body, any one of the driven members is defined as an estimation target of the position of the center of gravity, and an actuator that drives the driven member to be estimated. A load detection device that detects the load of the During the execution of the center of gravity position estimation operation for rotating the driven member, the moment generated around the rotation axis is calculated by the thrust of the actuator based on the load detected by the load detection device, and the center of gravity position is calculated. During the execution of the estimation operation, the horizontal distance from the rotation axis to the position of the center of gravity of the estimation target is calculated as the arm length based on the moment and the weight of the driven member of the estimation target that is known in advance. Then, during the execution of the center of gravity position estimation operation, the angle around the rotation axis and the distance from the rotation axis based on the rotation angle detected by the rotation angle detection device and the arm length. As a result, a parameter calculation unit for estimating the position of the center of gravity of the driven member to be estimated is provided.

According to the working machine of the present invention, when the driven member constituting the working device is replaced, the parameter information regarding the driven member can be obtained by a simple procedure, and the replacement work of the driven member as a whole can be facilitated. And it can be carried out quickly.

It is a block diagram of the hydraulic excavator which concerns on embodiment. It is explanatory drawing which shows the angle detection state of each part of the hydraulic excavator by the angle sensor. It is a hydraulic circuit diagram which shows the structure of the hydraulic circuit of a hydraulic excavator together with a control controller. It is a detailed view of the solenoid valve unit in FIG. It is a control block diagram which shows the system configuration centering on the control controller of a hydraulic excavator. It is a functional block diagram of the control controller of 1st Embodiment. It is a flowchart which shows the control flow which is carried out by the parameter calculation part of 1st Embodiment. It is a figure which shows the input screen of an input device. It is explanatory drawing which shows the posture of the hydraulic excavator at the time of performing the center of gravity position estimation operation. It is explanatory drawing which shows the balance of the moment around a bucket. It is explanatory drawing which shows the calculation procedure of the moment Tc. It is explanatory drawing which shows the calculation procedure of the center of gravity position of a bucket. It is a characteristic diagram which summarized the measurement result of the rotation angle γ of the bucket and the arm length Lw of the moment. It is a functional block diagram of the control controller of the 2nd Embodiment. It is a flowchart which shows the control flow which is carried out by the parameter calculation part of 2nd Embodiment. It is explanatory drawing which shows the calculation procedure of the center of gravity position of a bucket when the posture of an arm is tilted from FIG. It is explanatory drawing which shows the example of the movement range of the center of gravity position according to the rotation of a bucket when the arm is in the posture of FIG. It is explanatory drawing which shows the example of the movement range of the center of gravity position according to the rotation of a bucket when the arm is rotated about 90 ° from the posture of FIG. 9 toward the vehicle body.

Hereinafter, an embodiment in which the present invention is embodied in a hydraulic excavator provided with a front working device will be described. In the following description, a hydraulic excavator having a bucket as a work tool at the tip of the front work device is illustrated, but an articulated excavator configured by connecting a plurality of driven members (boom, arm, work tool, etc.). As long as it has a type of work device, it can be applied to work machines other than hydraulic excavators.

First, prior to the description of the embodiment, it will be described based on what kind of knowledge the present invention was conceived. As described in [Problems to be Solved by the Invention], parameters of each part of the hydraulic excavator are required to calculate ZMP, and a boom, an arm, a work tool, etc., which are driven members constituting the work device, are required. When it is replaced, it is necessary to update the parameters of the driven member after the replacement. However, in the techniques of Patent Documents 1 and 2, it is necessary to actually measure the parameters of a single driven member for that purpose.

In view of these problems, the present inventor is particularly complicated to measure the position of the center of gravity in the parameters of the driven member as compared with the weight and external dimensions. Therefore, if the measurement work can be omitted, the driven member as a whole is driven. We focused on the fact that the replacement work of parts can be simplified. Then, when the driven member is rotated while the driven member is assembled to the working device, the driven member is driven by the hydraulic cylinder against the moment centered on the rotation shaft generated by the weight of the driven member. The member is driven. During this rotation, the moment on the driven member side and the moment on the hydraulic cylinder side are kept in a balanced state, and the moment on the hydraulic cylinder side and the weight of the driven member can be specified. The position of the center of gravity of the driven member can be estimated with respect to the moving axis.
Based on the above findings, in the present embodiment, the position of the center of gravity of the bucket of the front working device is estimated as the driven member, and the first and second embodiments will be described below.

<First Embodiment>
<Basic configuration>
FIG. 1 is a configuration diagram of a hydraulic excavator according to an embodiment, and FIG. 2 is an explanatory diagram showing an angle detection state of each part of the hydraulic excavator by an angle sensor.
As shown in FIG. 1, the hydraulic excavator 1 is composed of a vehicle body 2 and an articulated front working device 3. The vehicle body 2 includes a lower traveling body 5 traveling by a traveling left hydraulic motor 4l and a traveling right hydraulic motor 4r, and an upper rotating body 7 mounted on the lower traveling body 5 and swiveled by a swivel hydraulic motor 6.

The front working device 3 is configured by connecting a boom 8, an arm 9, and a bucket 10 as a plurality of driven members that rotate in each of the vertical directions. The base end of the boom 8 is rotatably supported at the front portion of the upper swing body 7 via the boom pin 8a. The arm 9 is rotatably connected to the tip of the boom 8 via an arm pin 9a, and to the tip of the arm 9 via a bucket pin 10a (corresponding to the rotation shaft of the present invention) of the bucket link 10b. The bucket 10 is rotatably connected. The boom 8 is driven by the boom cylinder 11, the arm 9 is driven by the arm cylinder 12, and the bucket 10 is driven by the bucket cylinder 13.

As shown in FIGS. 1 and 2, the boom angle sensor 14 is attached to the boom pin 8a, the arm angle sensor 15 is attached to the arm pin 9a, and the bucket is capable of measuring the rotation angles α, β, and γ of the boom 8, arm 9, and bucket 10. The bucket angle sensor 16 is attached to the pin 10a. A vehicle body tilt angle sensor 17 that detects the tilt angle θ of the upper swivel body 7 with respect to the reference surface F (for example, a horizontal plane) is attached to the upper swivel body 7. The angle sensors 14 to 16 can be replaced with angle sensors with respect to the reference plane F, respectively. A swivel angle sensor 18 is attached to the swivel center axis so that the relative angle between the upper swivel body 7 and the lower traveling body 5 can be measured. Since these sensors 14 to 18 detect the posture of the front working device 3, they may be collectively referred to as the posture detecting device 19 in the following description.

<Flood control circuit>
FIG. 3 is a hydraulic circuit diagram showing the configuration of the hydraulic circuit of the hydraulic excavator 1 together with the control controller.
As shown in FIGS. 1 to 3, a control controller 20 for controlling the hydraulic excavator 1 is installed in the driver's cab 21 provided in the upper swing body 7. The control controller 20 is for operating the left motor operating device 22 having the traveling left lever 22a for operating the traveling left hydraulic motor 4l (lower traveling body 5) and the traveling right hydraulic motor 4r (lower traveling body 5). A right motor operating device 23 having a traveling right lever 23a, and an arm / turning operating device 24 having an operation left lever 24a for operating the arm cylinder 12 (arm 9) and the swivel hydraulic motor 6 (upper swivel body 7). , A boom / bucket operating device 25 having an operating right lever 25a for operating the boom cylinder 11 (boom 8) and the bucket cylinder 13 (bucket 10) is connected.

An operation signal is input to the control controller 20 from the corresponding operating devices 22 to 25 in response to the lever operation for each of the levers 22a to 25a. Since these operating devices 22 to 25 detect the operating state of the front working device 3, they may be collectively referred to as the operating device 26 in the following description.

The engine 27, which is a prime mover mounted on the upper swing body 7, drives the hydraulic pumps 28 and 29 and the pilot pump 30. The hydraulic pumps 28 and 29 are variable displacement pumps whose capacities are controlled by regulators 28a and 29a, and the pilot pump 30 is a fixed capacitance pump. The hydraulic pumps 28 and 29 and the pilot pump 30 suck pressure oil from the tank 31. Although the detailed configuration of the regulators 28a and 29a is omitted, the regulators 28a and 29a are driven according to the control signal input from the control controller 20, and the discharge flow rates of the hydraulic pumps 28 and 29 are controlled.

The pressure oil discharged from the hydraulic pumps 28 and 29 is supplied to the flow control valves 32 to 37, and each flow rate is controlled by the pilot pressure input from the electromagnetic proportional valves 44a, 44b to 46a, 46b of the solenoid valve unit 43 described later. The valves 32 to 37 are switched respectively. When the pressure oil from the hydraulic pumps 28 and 29 is supplied to the traveling left hydraulic motor 4l and the traveling right hydraulic motor 4r in response to this switching, the lower traveling body 5 travels as the hydraulic motors 4l and 4r rotate. do. Further, when pressure oil is supplied to the boom cylinder 11, the arm cylinder 12, and the bucket cylinder 13, the boom 8, arm 9, and bucket 10 rotate as the cylinders 11 to 13 expand and contract, respectively, and the position of the bucket 10 is reached. And the posture changes. Further, when the pressure oil is supplied to the swivel hydraulic motor 6, the upper swivel body 7 swivels with respect to the lower traveling body 5 as the swivel hydraulic motor 6 rotates.

The boom cylinder 11, arm cylinder 12, and bucket cylinder 13 are provided with pressure sensors 38a, 38b to 40a, 40b for detecting the pressure in the bottom chamber and the rod chamber, respectively, from the pressure sensors 38a, 38b to 40a, 40b, respectively. The detection signal is input to the control controller 20. Since these pressure sensors 38a, 38b to 40a, 40b detect the load state of the front work device 3, they may be collectively referred to as the load detection device 41 in the following description.

FIG. 4 is a detailed view of the solenoid valve unit 43 in FIG. In the figure, the electromagnetic proportional valves 44a, 44b to 46a, 46b corresponding to the flow control valves 32 to 34 of the boom cylinder 11, the arm cylinder 12, and the bucket cylinder 13 are excerpted, and description and illustration are omitted. The electromagnetic proportional valves corresponding to the traveling hydraulic motors 4l and 4r and the swing hydraulic motor 6 have the same configuration.

Electromagnetic proportional valves 44a, 44b to 46a, 46b are connected to the hydraulic drive units 32a, 32b to 34a, 34b of the flow control valves 32 to 34 via pilot lines 47a, 47b to 49a, 49b, respectively. Pressure oil from the pilot pump 30 is supplied to the proportional valves 44a, 44b to 46a, 46b via the pump line 50.

The control controller 20 is electrically connected to the electromagnetic proportional valves 44a, 44b to 46a, 46b, and the control signal corresponding to the operation signal from the operating devices 22 to 25 is input from the control controller 20, and each electromagnetic proportional valve 44a , 44b to 46a, 46b are switched respectively. Then, the pressure oil from the pilot pump 30 is depressurized and input to the corresponding flow control valves 32 to 37 as the pilot pressure according to the switching of the electromagnetic proportional valves 44a, 44b to 46a, 46b, and as described above, each of them. The hydraulic excavator 1 is operated by driving the hydraulic actuators 4l, 4r, 6, 11-13.

Since the electromagnetic proportional valves 44a, 44b to 46a, 46b are controlled in opening degree in response to the control signal from the control controller 20 in this way, the control controller 20 is used even when the lever is not operated on the operating device 26. Is capable of forcibly driving the electromagnetic proportional valves 44a, 44b to 46a, 46b, and by extension, driving the hydraulic actuators 4l, 4r, 6, 11 to 13.

As shown in FIG. 2, a lock valve 51 configured as an electromagnetic switching valve is interposed in the pump line 50, and a position detector of a gate lock lever (not shown) arranged in the cab 21 is electrically connected. ing. The gate lock lever is switched between the lock position and the unlock position, and the corresponding position signal is input to the lock valve 51. At the lock position of the gate lock lever, the lock valve 51 closes and shuts off the pump line 50. Then, at the unlocked position, the lock valve 51 opens to open the pump line 50. As a result, the operation can invalidate the unintended lever operation on the operating device 26 and prohibit operations such as traveling, turning, and excavation by switching the gate lock lever to the locked position.

<System configuration>
FIG. 5 is a control block diagram showing a system configuration centered on the control controller 20 of the hydraulic excavator 1.
The control controller 20 includes an input unit 53, a central processing unit (CPU) 54 which is a processor, a read-only memory (ROM) 55 and a random access memory (RAM) 56 which are storage devices, and an output unit 57. ing. The input unit 53 includes detection signals from the sensors 14 to 18 constituting the attitude detection device 19, operation signals from the operation devices 22 to 25 constituting the operation device 26, and sensors 38a constituting the load detection device 41. The detection signals from 38b to 40a and 40b are input and converted so that the CPU 54 can calculate.

The ROM 55 is a recording medium in which a control program for executing control contents including processing related to a flowchart described later and various information necessary for executing the flowchart are stored, and the CPU 54 is a control stored in the ROM 55. A predetermined arithmetic process is performed on the signals taken in from the input unit 53 and the memories 55 and 56 according to the program. The output unit 57 creates a control signal according to the calculation result of the CPU 54, and outputs the signal to the electromagnetic proportional valves 44a, 44b to 46a, 46b and the display device 58 (for example, a liquid crystal display). As a result, the operation of the front working device 3 (hereinafter referred to as “the position of the center of gravity of the bucket 10) required for driving and controlling each of the hydraulic actuators 4l, 4r, 6, 11 to 13 and calculating the parameters (center of gravity position of the bucket 10) of the driven member to be described later). The operation of estimating the position of the center of gravity) is displayed on the screen of the display device 58.

FIG. 6 is a functional block diagram of the control controller 20.
The control controller 20 includes an electromagnetic proportional valve control unit 60, a display control unit 61, a parameter setting unit 62, and a vehicle body stability calculation unit 63. The parameter setting unit 62 includes a parameter calculation unit 62a and a parameter storage unit 62b.
When the operating device 26 is operated by the lever, the electromagnetic proportional valve control unit 60 outputs a control signal according to the operation amount and the operation direction to the electromagnetic proportional valves 44a, 44b to 46a, 46b.

The display control unit 61 is a part that controls the display device 58 based on the work device posture and work operation contents output from the parameter calculation unit 62a. The display control unit 61 is provided with a display ROM in which a large number of display-related data including images and icons of the front work device 3 are stored, and the display control unit 61 is predetermined based on a flag included in the input information. The program is read and the display control on the display device 58 is performed.

The parameter calculation unit 62a calculates the position of the center of gravity of the bucket 10 based on the work device posture detected by the posture detection device 19 and the load detected by the load detection device 41 in the control flow described later. The parameter calculation unit 62a outputs the calculation result to the parameter storage unit 62b, and stores the parameters of the bucket 10.
The parameter storage unit 62b is further provided to store the parameters input by the input device 64.

The vehicle body stability calculation unit 63 calculates, for example, the ZMP of the vehicle body 2 based on the posture information of the front work device 3 from the sensors 14 to 18 constituting the attitude detection device 19 and the parameters stored in the parameter storage unit 62b. Calculate. Since ZMP is well known, details will not be described, but the stability of the posture of the vehicle body 2 is determined based on the comparison between the ZMP and the polygon obtained from the ground contact point of the hydraulic excavator 1 with respect to the ground surface. The calculation unit 63 outputs the determination result to the display control unit 61 so that the determination result can be transmitted to the operator.

<Control flow of parameter calculation>
FIG. 7 is a flowchart showing a control flow executed by the parameter calculation unit 62a, and FIG. 8 is a diagram showing an input screen of the input device.
In the control flow of FIG. 7, the parameters necessary for calculating the position of the center of gravity of the bucket 10 are input on the input screen of the input device 64 shown in FIG. 8, the weight, the dimension A, and the angle B are input, and then the parameter calculation mode is entered. It is carried out by tapping the transition button 64a to migrate.

In S400, the posture of the front working device 3 for calculating the position of the center of gravity and the content of the operation of estimating the position of the center of gravity are displayed on the display device 58 via the display control unit 61 (corresponding to the guidance execution unit of the present invention). As shown in FIG. 9, the posture of the front working device 3 at this time is such that the straight line L connecting the arm pin 9a connecting the boom 8 and the arm 9 and the bucket pin 10a connecting the arm 9 and the bucket 10 is in the direction of gravity. The posture is vertical. At this time, the bucket cylinder 13 has the maximum contraction length, and the content of the center of gravity position estimation operation is to operate the bucket cylinder 13 in the extension direction to rotate the bucket 10 downward about the bucket pin 10a. .. The speed of the center-of-gravity position estimation operation is instructed to be performed in a slow motion in order to reduce the influence of the inertial load when calculating the center-of-gravity position in S420 described later. The rotation direction of the bucket 10 is not limited to the downward direction, and conversely, the bucket 10 may be rotated upward with the bucket pin 10a as the center.

While the operator is operated in S400 and the center of gravity position estimation operation is being performed, the posture detection device 19 and the load detection device 41 continue to measure the detected values.
In S410, it is determined whether or not the center of gravity position estimation operation is completed. The determination criteria are that the operator's operation has been completed and that the measurement of the measurement data for calculation in the next S420 has been completed. When the determination of S410 is NO (negative), the process returns to S400 and the measurement is performed again. If the determination in S410 is YES (affirmative), the process proceeds to S420.

In S420, the position of the center of gravity is calculated from the result measured in S400. The specific calculation contents will be described later with reference to FIGS. 10 to 13.
In S430, the position of the center of gravity of the bucket 10 which is the calculation result is stored in the parameter storage unit 62b, and the parameter calculation mode is terminated.

<Calculation procedure of the position of the center of gravity>
Next, the calculation procedure of the position of the center of gravity of the bucket 10 executed in S420 of FIG. 7 will be described.
FIG. 10 is an explanatory diagram showing the balance of moments around the bucket 10. The X-axis is the straight line L connecting the arm pin 9a connecting the boom 8 and the arm 9 and the bucket pin 10a connecting the arm 9 and the bucket 10, the vertical direction perpendicular to the X-axis is the Z-axis, and the axis of the bucket pin 10a. Is defined as the origin O.

The moment around the origin O generated by the thrust Fb of the bucket cylinder 13 is Tc, the force due to the weight of the bucket 10 acting on the position of the center of gravity of the bucket 10 is Fw (corresponding to the weight of the driven member to be estimated by the present invention), and the origin. Assuming that the arm length of the moment generated by Fw around O is Lw (corresponding to the arm length of the present invention), the relational expression as in the following equation (1) holds.

Tc = Fw × Lw …… (1)
Here, Tc can be obtained by a procedure described later based on FIG. 11, and Fw can be calculated from the weight value of the item input in FIG. That is, Lw can be calculated from these results.
FIG. 11 shows a method of calculating Tc. Tc is obtained by multiplying the moment Tb around the point C generated by the thrust Fb of the bucket cylinder 13 by the conversion ratio R (γ) of the link whose variable is the rotation angle γ of the bucket 10 acquired from the attitude detection device 19. Desired.

Tc = Tb × R (θγ) …… (2)
Tb is obtained by multiplying the component perpendicular to BC of Fb by the length of BC.

Here, Fb is multiplied by the pressure receiving area of the cylinder from the pressure in the bottom chamber and the pressure in the rod chamber detected by the pressure sensor 40a and the pressure sensor 40b (corresponding to the load detection device of the present invention) attached to the bucket cylinder 13. You can get it by.

After calculating Lw by the above procedure, the position of the center of gravity of the bucket 10 can be calculated by the method shown in FIG.
The distance from the origin O to the bucket center of gravity is Lcog (corresponding to the distance from the rotation axis of the present invention), the line segment connecting the origin O and the bucket tip and the line segment connecting the origin O and the bucket center of gravity are formed. Assuming that the angle is θcog (corresponding to the angle centered on the rotation axis of the present invention), the relational expression as shown in the following equation (10) holds.

L _W = L _cog・ cos (θ _cog ＋ γ) …… (4)
From the equation (4), when γ and Lw are measured while changing the posture of the bucket 10, the relationship of the cosine wave as shown in FIG. 13 can be obtained. The bucket angle sensor 16 that detects the rotation angle γ corresponds to the rotation angle detection device of the present invention. From the characteristics of this cosine wave, Lcog and θcog, which are parameters that determine the position of the center of gravity, can be calculated by searching for γ', which maximizes Lw, as a feature point.

As described above, according to the hydraulic excavator 1 of the present embodiment, when the bucket 10 of the front work device 3 is replaced, the weight and external dimension parameters of the bucket 10 which are easy to measure as compared with the position of the center of gravity are input to the input device 64. The center of gravity position of the bucket 10 can be automatically calculated by simply executing the center of gravity position estimation operation according to the guidance provided by the display device 58. Therefore, the replacement work of the bucket 10 as a whole including the measurement work when replacing the bucket 10 can be easily and quickly performed.

As a result, the vehicle body stability calculation unit 63 executes arithmetic processing related to stability such as ZMP of the vehicle body 2 based on the parameters according to the mounted bucket 10, and presents the information to the operator by the display device 58. be able to.
Further, since the position of the center of gravity of the bucket 10 calculated by the parameter calculation unit 62a is stored in the parameter storage unit 62b, the position of the center of gravity of the bucket 10 stored in the parameter storage unit 62b is read out during the next and subsequent work, and an operation such as ZMP is performed. It can be used for processing. Therefore, the work can be started without executing the parameter input and the center of gravity position estimation operation required for the calculation process of the center of gravity position.

<Second Embodiment>
Next, the second embodiment will be described with reference to FIGS. 14 and 15. Since the configurations described with reference to FIGS. 1 to 5 are the same as those of the first embodiment, the same member numbers will be assigned and the description will be omitted, and the differences will be mainly described.

FIG. 14 is a functional block diagram of the control controller 20.
Unlike the first embodiment, the parameter calculation unit 62a is configured to be able to control the electromagnetic proportional valves 44a, 44b to 46a, 46b, and the output of the parameter calculation unit 62a is input to the electromagnetic proportional valve control unit 60. Further, the vehicle body stability calculation unit 63 is adapted to input its output to the electromagnetic proportional valve control unit 60 so that the operations of the hydraulic actuators 4l, 4r, 6, 11 to 13 can be restricted. When it is presumed that the posture of the vehicle body 2 is unstable, the operation of the hydraulic actuators 4l, 4r, 6, 11 to 13 is restricted by the parameter calculation unit 62a, and the vehicle body 2 is stabilized.

FIG. 15 is a flowchart showing a control flow executed by the parameter calculation unit 62a.
In S500, the state waits for the start instruction input of the center of gravity position estimation operation for calculating the center of gravity position. As an operation start instruction input means, a tappable button is added to the input screen of FIG. 8 (not shown). This is an example, and the input means for the operation start instruction may be inputting a specific lever operation or the like.

In S510, it is determined whether or not the operation start instruction is input. If NO in S510, the process returns to S500, and if YES, the process proceeds to S520.
In S520, the center of gravity position estimation operation is started, and the electromagnetic proportional valve 46a is driven to extend and drive the bucket cylinder 13.
When the operation is completed in S520, the process proceeds to S530 and the position of the center of gravity is calculated.
In S540, the calculation result is stored in the parameter storage unit 62b.

となる。最小二乗法を用い、式(5)中の

Ｌｗに相当する測定結果の行列をＢ、

ＡＸ＝Ｂ ……(6)

Ｘ＝（Ａ^ＴＡ）⁻¹Ａ^ＴＢ ……(8)

となる。 Hereinafter, the calculation procedure of the position of the center of gravity of the bucket 10 will be described with reference to FIG. 12 used in the first embodiment.
As in the first embodiment, the above equation (4) holds.
When this equation (4) is decomposed using the addition theorem and expressed in a matrix,

Will be. Using the least squares method, in Eq. (5)

The matrix of measurement results corresponding to Lw is B,

AX = B …… (6)

X = (A ^T A) ^-1 A ^T B …… (8)

Will be.

As a result, a cosine wave representing the relationship between Lw and γ as shown in FIG. 13 is estimated based on a plurality of measurement points consisting of Lw and γ, and the maximum value of Lw and the maximum value of this Lw are obtained from the cosine wave. The corresponding γ'can be obtained as a feature point, and the parameters Lcog and θcog that determine the position of the center of gravity can be obtained based on the maximum value of these Lw and γ'.
Then, in the center of gravity position estimation operation, it is not necessary to measure all of the characteristic lines consisting of Lw and γ shown in FIG. 13, and even if the measurement points do not include γ'which maximizes Lw, the estimation is performed. The maximum value of Lw and γ'can be obtained from the cosine wave.

As described above, according to the hydraulic excavator 1 of the present embodiment, as in the first embodiment, when the bucket 10 of the front working device 3 is replaced, the position of the center of gravity of the bucket 10 can be automatically calculated. The replacement work of the bucket 10 can be carried out easily and quickly. In addition, it is possible to execute arithmetic processing related to the stability of the vehicle body 2 such as ZMP based on the parameters according to the mounted bucket 10, and it is possible to store the calculated parameters and use them in the next and subsequent work.

Moreover, in the present embodiment, since the center of gravity position estimation operation required for calculating the center of gravity position is automatically executed, the burden on the operator can be further reduced.
Further, since the operation of the hydraulic actuators 4l, 4r, 6, 11 to 13 is restricted from the result of the vehicle body stability calculation, the hydraulic actuators 4l, 4r, 6, 11 to 13 are configured when the posture of the vehicle body 2 is unstable. The operation of is restricted, and more stable work can be performed.

By the way, in the first and second embodiments described above, the center of gravity position estimation operation for calculating the center of gravity position with the arm 9 as a specific posture is executed as shown in FIG. 9, but the posture is not limited to this arm 9. In that case, it is necessary to add a correction to the calculation of the position of the center of gravity according to the angle between the arm 9 and the direction of gravity, and this correction process will be described below.

FIG. 16 is an explanatory diagram showing a calculation procedure of the position of the center of gravity of the bucket 10 when the posture of the arm 9 is tilted from that of FIG. The direction vertically upward with respect to the earth is defined as the Z axis, and the direction perpendicular to the Z axis, passing through the connection point A between the bucket 10 and the arm 9, and perpendicular to the bucket pin 10a and the arm pin 9a is defined as the X axis. Xa is an arm-based coordinate system in which the X-axis and the Z-axis are rotated around the point A so that the straight line connecting the arm pin 9a and the bucket pin 10a overlaps the X-axis on the same plane as the X-Z plane. Define the axis and Za axis. The rotation angle γ of the bucket 10 is the angle formed by Xa and AE.
Here, in order to calculate Lw, as shown in the following equation (11), it is necessary to use the angle φ formed by the X-axis and AE instead of γ.

Lw = L _cog cos (θ + φ) …… (12)
Since φ is the rotation angle of the bucket 10 with respect to the X axis, as shown in FIG. 2, the inclination angle θ, the boom angle α, the arm angle β, and the bucket angle γ of the vehicle body 2 (upper swing body 7) in the pitch direction are used. , Is obtained as in the following equation (12). Lw can be obtained by using this φ.

φ ＝ θ ＋ α ＋ β ＋ γ …… (13)

Further, in the first embodiment, in addition to the correction of the rotation angle γ of the bucket 10 described above, it is necessary to pay attention to the following points, which will be described below.
FIG. 17 is an explanatory view showing an example of a movement range of the position of the center of gravity according to the rotation of the bucket 10 when the arm 9 is in the posture of FIG. 9, and FIG. 18 is an explanatory view in which the arm 9 is about 90 ° from the posture of FIG. It is explanatory drawing which shows the example of the movement range of the center-of-gravity position according to the rotation of a bucket 10 when it rotates.
In the first embodiment, the position of the center of gravity is calculated by obtaining the maximum value of Lw. The maximum value of Lw is the point where the center of gravity positions intersect on the positive side of the X axis as the bucket 10 rotates. In the example of FIG. 17, the point where Lw is maximum (the center of gravity position of the bucket 10 is the X axis). Since the points that intersect on the positive side) are included in the movement range of the position of the center of gravity of the bucket, calculation is possible.

On the other hand, in the case of FIG. 18, since the point where Lw is maximized is not included in the moving range of the bucket center of gravity position, the center of gravity position of the bucket 10 cannot be calculated by obtaining the maximum value of Lw. Therefore, in this case, instead of the point where Lw is maximum, the point where Lw is minimum (the point where the position of the center of gravity of the bucket 10 intersects on the negative side of the X axis) or the point where Lw = 0 is set as a feature point. By extracting, the position of the center of gravity of the bucket 10 can be calculated. As described above, even if the posture of the arm 9 is not shown in FIG. 9, the position of the center of gravity of the bucket can be calculated in the same manner as in the first and second embodiments by implementing the calculation method in consideration of the posture.

Although the description of the embodiment is completed above, the aspect of the present invention is not limited to this embodiment and can be changed in various ways. For example, in each of the above embodiments, the position of the center of gravity of the bucket 10 is calculated, but the position of the center of gravity of the boom 8 and the arm 9 can also be calculated in the same way. That is, the present invention may be applied when the arm 9 of the front working device 3 is replaced with an arm longer than the standard.

Further, in each of the above embodiments, the angle sensors 14 to 16 for detecting the angles of the boom 8, the arm 9, and the bucket 10 are used, but even if the posture information of the hydraulic excavator 1 is calculated by the cylinder stroke sensor instead of the angle sensor. good. Further, although the electric lever type hydraulic excavator 1 has been described as an example, the hydraulic excavator of the hydraulic pilot type may be configured to control the command pilot pressure generated from the hydraulic pilot.

Further, each configuration related to the above-mentioned control controller 20, functions and execution processing of each configuration are realized by hardware (for example, designing logic for executing each function with an integrated circuit) in part or all of them. You may. Further, the configuration related to the control controller 20 may be a program (software) that realizes each function related to the configuration of the control controller 20 by being read and executed by an arithmetic processing unit (for example, a CPU). Information related to the program can be stored in, for example, a semiconductor memory (flash memory, SSD, etc.), a magnetic storage device (hard disk drive, etc.), a recording medium (magnetic disk, optical disk, etc.), or the like.
Further, in each of the above embodiments, the number of measurements is not described when calculating the position of the center of gravity of the bucket 10, but the measurement is performed a plurality of times in order to reduce the influence of the measurement error, and the position of the center of gravity is calculated using the result. You may.

1 Hydraulic excavator (working machine)
2 Body 3 Front work equipment 10 Driven member (bucket)
10a bucket pin (rotating shaft)
13 Bucket cylinder (actuator)
40a, 40b pressure sensor (load detector)
16 Bucket angle sensor (rotation angle detector)
62a Parameter calculation unit 61 Display control unit (guidance execution unit)
58 Display device (guidance execution unit)
60 Electromagnetic proportional valve control unit 63 Body stability calculation unit 63 Parameter storage unit

Claims (8)

Work in which a plurality of driven members are connected to each other via a rotation shaft to form an articulated work device in which each of the driven members can be rotated by driving an actuator, and the work device is provided on a vehicle body. In the machine
A load detection device that determines the position of the center of gravity of any one of the driven members as an estimation target and detects the load of the actuator that drives the driven member to be estimated.
A rotation angle detection device that detects a rotation angle around the rotation axis of the driven member to be estimated, and a rotation angle detection device.
During the execution of the center of gravity position estimation operation for rotating the driven member to be estimated around the rotation axis, the rotation axis is centered by the thrust of the actuator based on the load detected by the load detection device. During the execution of the center-of-gravity position estimation operation, the position of the center of gravity of the estimation target from the rotation axis is calculated based on the moment and the weight of the driven member to be estimated, which is known in advance. The distance in the horizontal direction up to is calculated as the arm length, and the center of gravity is centered on the rotation axis based on the rotation angle detected by the rotation angle detection device and the arm length during the execution of the center of gravity position estimation operation. A work machine including a parameter calculation unit that estimates the position of the center of gravity of the driven member to be estimated as the angle and the distance from the rotation axis. The parameter calculation unit sets the maximum value of the arm length as the distance from the rotation axis representing the center of gravity position during the execution of the center of gravity position estimation operation, and when the maximum value of the arm length is calculated. The work machine according to claim 1, wherein the rotation angle detected by the rotation angle detection device is an angle centered on the rotation axis representing the position of the center of gravity. The parameter calculation unit determines the arm length and the rotation angle based on a plurality of measurement points of the arm length and the rotation angle detected by the rotation angle detection device during the execution of the center of gravity position estimation operation. The cosine wave representing the relationship is estimated, and the maximum value of the arm length obtained from the cosine wave is defined as the distance from the rotation axis representing the position of the center of gravity, and the number of times corresponding to the maximum value of the arm length obtained from the cosine wave. The work machine according to claim 1, wherein the moving angle is an angle centered on the rotation axis representing the position of the center of gravity. The work machine according to any one of claims 1 to 3, further comprising a guidance execution unit that guides the operator of the work machine to estimate the position of the center of gravity. The work machine according to any one of claims 1 to 4, wherein the parameter calculation unit further drives and controls the actuator to execute the center of gravity position estimation operation. The ZMP of the work machine is calculated based on the position of the center of gravity estimated by the parameter calculation unit, and the posture of the work machine is stabilized based on the comparison between the ZMP and the polygon obtained from the ground contact point of the work machine with respect to the ground surface. The work machine according to any one of claims 1 to 5, further comprising a vehicle body stability calculation unit for determining a degree. A parameter storage unit that stores the position of the center of gravity estimated by the parameter calculation unit is further provided.
When the work of the work machine is started, the vehicle body stability calculation unit reads out the position of the center of gravity stored in the parameter storage unit at the time of the previous work of the work machine and performs the ZMP estimation process of the work machine. The work machine according to claim 6, wherein the work machine is to be executed. 6. Or 7, the vehicle body stability calculation unit further drives and controls the actuator of the work machine in a stable direction when it is determined that the posture of the work machine is unstable. The work machine described in.

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