JP2699097B2 - Bucket edge depth control device for construction machinery - Google Patents

Description

The present invention relates to a construction machine provided with a bucket, an arm, and a boom. The invention relates to a bucket cutting edge depth which is set to a predetermined target value. It relates to a control device.

[Conventional technology]

Generally, a hydraulic excavator includes a boom, an arm, and a bucket, and hydraulic cylinders for operating the boom cylinder, the arm cylinder, and the bucket cylinder. Each of these hydraulic cylinders is separately operated by three operation levers provided in a driver's seat. Operated.

When the ground is excavated linearly by such a hydraulic excavator, it is required that the vertical tip position of the bucket (depth of the cutting edge of the bucket) be maintained at a predetermined target value. Therefore, the operator must operate two or three of the above operating levers in a complex and simultaneous manner during a straight excavation operation so that the movement trajectory of the bucket tip is straight on a desired plane.

However, the operation of manually controlling the depth of the blade edge of the hydraulic power shovel by operating the two or three operation levers in a complex manner requires a great deal of skill. In addition, it is time-consuming to control the cutting edge depth with high accuracy, and the working efficiency is greatly impaired.

In view of the above circumstances, various conventional techniques have been proposed and implemented in which the bucket blade depth is automatically controlled to be constant by simply operating only the arm operation lever.

All the prior arts focus on the fact that a fixed geometric relationship is established between the rotation angle of the boom, the arm and the bucket and the depth of the cutting edge of the bucket, and utilizing such a principle, the rotation of the boom, the arm and the bucket is utilized. The angle is detected, the bucket cutting edge depth is calculated from the detected rotation angles, and control is performed so that the calculated cutting edge depth becomes constant.

For example, in Japanese Patent Publication No. 58-36135, “Method of controlling excavation depth in excavator”, a deviation between a current value of a bucket edge depth and a target value of the same is determined, and a flow rate corresponding to the deviation is determined. The command is given to the boom cylinder.

[Problems to be solved by the invention]

Conventionally, the intended purpose of automatically setting the bucket edge depth to a desired target value by operating only one arm operating lever is certainly achieved, but in any case, the bucket edge depth is Since the control is based on the comparison between the current value and the target value, the following problems naturally occur in combination with the characteristics of the hydraulic system.

That is, the hydraulic control system of the working machine of the hydraulic power shovel has a large inertia due to the load and a large response delay. Also, the flow characteristics of the hydraulic operation valve that supplies the pressure oil to each cylinder fluctuates according to the load.

Therefore, for example, in the prior art, even if the operation lever for the arm is operated, the arm does not immediately turn at a speed corresponding to the operation amount of the lever due to the response delay.

Under these circumstances, even if a flow command is output to the boom cylinder based on the rotation angle of the arm, etc., there is a response delay before the boom rotates with respect to the boom flow command, so the boom rotates based on the flow command. According to this advantage, since the arm has already been rotated further, the bucket edge depth does not match the target value.

Also, the bucket tip depth is such that a flow command according to the deviation between the current value and the target value is given to the boom cylinder, but even if the same flow command (boom cylinder speed) is given to the boom cylinder, The rotational angular velocity of the arm actually generated differs depending on the rotational angle of the arm and the rotational angle of the boom, and the deviation cannot always be made zero. For this reason, conventionally, it is necessary to set a control gain for making the deviation zero to a value at which the system does not become unstable regardless of the rotation angle of the arm and the boom, however, due to the response delay. Can only be set to a relatively low value. However, this would affect the accuracy of bucket edge depth control.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and it is possible to improve the delay of control response and to give an accurate command to a boom, thereby enabling accurate and stable control of bucket edge depth. Its purpose is to provide a device.

[Means and actions for solving the problem]

Therefore, in the present invention, a boom that is rotatably attached to one point of the vehicle body and that is controlled to rotate by a first actuator, and that is rotatably mounted to a tip of the boom and that is controlled to rotate by a second actuator. In a construction machine having an arm and a bucket attached to a tip of the arm and controlled to rotate by a third actuator, a rotation angle detecting means for detecting each rotation angle of the boom, the arm and the bucket, and the arm Operation amount detection means for detecting an operation amount of an arm operation lever for operating the control unit; arm control means for controlling the second actuator in accordance with the operation amount of the arm operation lever; output of the rotation angle detection means; The amount of operation of the arm operation lever is determined based on the amount of operation of the arm operation lever detected by the operation amount detection unit. First drive command value creating means for creating a drive command value for the first actuator that makes the change in the edge depth of the bucket zero, and target setting means for setting a target value for the edge depth of the bucket A current value calculating means for calculating a current value of the cutting edge depth of the bucket based on an output of the rotation angle detecting means, an output of the rotation angle detecting means, a set target value of the target value setting means, A second drive command value creating means for creating a drive command value for the first actuator for making a deviation between the set target value and the current value zero based on the current value calculated by the current value calculation means; And means for controlling the drive of the first actuator in accordance with the sum of the drive command values created by the first and second drive command value creating means.

According to this configuration, the following operation is achieved. The arm control means controls the second operation in accordance with the operation amount of the arm operation lever.
To control the actuator to rotate the arm.

On the other hand, the first drive command value creating means creates a drive command value for the first actuator for setting the bucket blade edge depth that changes according to the operation amount to zero.

Further, the second drive command value creating means is configured to set a first value for setting a deviation between a set target value of the bucket edge depth and a current value to zero.
Create a drive command value for the actuator.

The drive of the first actuator is controlled in accordance with the sum of the drive command values. As a result, the first actuator is not simply controlled in accordance with the drive command value corresponding to the deviation of the bucket edge depth, but is driven in consideration of the predicted change amount of the arm operation lever with respect to the drive command value. The drive is controlled by the drive command value to which the command value is added. Therefore, even if the arm is rotated with a response delay by the arm control means, the first actuator is driven in consideration of the response delay, and the boom is rotated so that the deviation becomes zero. Will do.

Further, in the present invention, a boom movably attached to one point of the vehicle body and rotated by a boom cylinder, an arm rotatably mounted at a tip of the boom and rotated by an arm cylinder, In a construction machine having a bucket mounted and rotated by a bucket cylinder, a rotation angle detecting means for detecting each rotation angle of the boom, the arm and the bucket, and an operation amount of an arm operation lever for operating the arm are detected. Operating amount detecting means, an arm controlling means for operating the arm cylinder at a speed corresponding to the operating amount of the arm operating lever to rotate the arm, and an arm operating lever detected by the operating amount detecting means. Arm cylinder speed calculation means for calculating a speed of the arm cylinder corresponding to the operation amount based on the operation amount Based on the rotation angle of the arm detected by the rotation angle detection means and the arm cylinder speed calculated by the arm cylinder speed calculation means, the rotation angle of the arm and the arm cylinder speed corresponding to the arm cylinder speed. Arm rotation angular velocity calculating means for calculating a rotation angular velocity; the bucket corresponding to the rotation angular velocity of the arm based on an output of the rotation angle detecting means and the rotation angular velocity of the arm calculated by the arm rotation angular velocity calculating means. First boom rotation angular velocity calculating means for calculating a rotation angular velocity of the boom for reducing a change in the cutting edge depth to zero; target value setting means for setting a target value of the cutting edge depth of the bucket; A current value calculating means for calculating a current value of the cutting edge depth of the bucket based on an output of the detecting means; an output of the rotation angle detecting means; Based on the set target value of the target value setting means and the current value calculated by the current value calculation means, a rotation angular velocity of the boom for zeroing a deviation between the set target value and the current value is calculated. Second
Based on the boom rotation angular velocity calculating means, the boom rotation angle detected by the rotation angle detecting means, and the boom rotation angular velocity respectively calculated by the first and second boom rotation angular velocity calculating means. Boom cylinder speed calculation means for calculating the sum of the rotation angular speeds of the boom and the speed of the boom cylinder corresponding to the rotation angle of the boom,
Means for operating the boom cylinder in accordance with the speed of the boom cylinder calculated by the boom cylinder speed calculating means to rotate the boom.

According to this configuration, the same operation as the above-described configuration is achieved, and the following operation is also achieved.

That is, according to the present invention, the arm rotation angular velocity can take different values depending on the rotation angle of the arm and the speed of the arm cylinder, and the arm rotation angular velocity differs depending on the rotation angle of the boom and the speed of the boom cylinder (the speed of the boom cylinder is different from that of the boom cylinder). (Depending on the rotation angular velocity and the rotation angle of the boom).

The arm rotation angular velocity calculation means calculates an accurate arm rotation angular velocity based on the point of interest, and the first boom rotation angular velocity calculation means calculates an accurate boom rotation angular velocity based on the accurate arm rotation angular velocity.

Further, the boom cylinder speed calculating means calculates an accurate boom cylinder speed based on the point of interest with respect to the boom rotation angular speed taking into account the accurate boom rotation angular speed.

Since the boom cylinder operates in accordance with the accurate speed of the boom cylinder obtained in this manner, the boom is accurately rotated so that the deviation of the bucket edge depth becomes zero.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of a bucket blade edge depth control device according to the present invention, FIG. 3 is a diagram showing an overall configuration of the embodiment, and FIG. 4 is a working machine of a hydraulic power shovel in the embodiment. FIG. 5 shows the geometric relationship of the working machine shown in FIG.

As shown in FIG. 4, the working machine (front attachment) of the hydraulic excavator PS includes respective mechanical parts of a boom 1, an arm 2, and a bucket 3, and their rotation fulcrums O, B, and C have their rotations. Angles α, β and γ
A boom angle detector 7, an arm angle detector 8, and a bucket angle detector 9 for detecting (see FIG. 5) are provided respectively. As these detectors 7, 8 and 9, for example, potentiometers are used.

In FIG. 5, the Y axis is a vertical axis passing through the fulcrum O, l ₁
The length l ₂ is the length of segment BC joining the support point B and C, l ₃ is the line segment CD length connecting the fulcrum C and the bucket end point D of the line segment OB is connecting the fulcrum O and B, L ₂ Is the length of a line segment BD connecting the fulcrum B and the bucket tip point D (hereinafter referred to as arm arm tip full length).

At this time, the rotation angle α is the rotation angle of the line segment OB with respect to the y-axis, the rotation angle β is the rotation angle of the line segment BC with respect to the extension of the line segment OB, and the rotation angle γ is the extension of the line segment BC. The rotation angle of the line segment CD with respect to the line is shown. Β ₀ indicates an angle formed by the line segment BD with respect to an extension of the line segment OB (hereinafter, referred to as an arm edge angle).

As is apparent from FIG. 5, between L ₂ , l ₂ , l ₃ and γ, Geometric relationship holds.

Here, since the rotation angle γ is detected by the detector 9 since l ₂ and l ₃ are known, it is possible to obtain the arm blade tip full length L ₂ by substituting the detected value into the equation (1). Will be possible.

Further, between the above β ₀ , β, l ₃ , γ and L ₂ , as is apparent from FIG. 5, β ₀ = β + sin ⁻¹ (l ₃ sin γ / L ₂ ) (2) A geometric relationship holds.

Here, since l ₃ is known and L ₂ is obtained by the above equation (1), when each of the rotation angles β and γ is detected by the detectors 8 and 9, these detected values are converted to (2) By substituting into the equation, it becomes possible to obtain the arm blade angle β ₀ .

The rotation angle signals indicating the rotation angles α, β and γ detected by the rotation angle detectors 7, 8 and 9 are applied to the CPU 22 of the controller 20 via the input interface 21 of the controller 20 shown in FIG. Can be

The boom 1, the arm 2, and the bucket 3 are rotated by a boom cylinder 4, an arm cylinder 5, and a bucket cylinder 6, respectively.

A boom operation lever (not shown) for rotating the boom 1, the arm 2, and the bucket 3, a control lever 10 for the arm, and a control lever 11 for the bucket are provided in the driver's seat of the hydraulic excavator PS. (See FIG. 1). The operating lever 10 has a lever angle detector that detects the operating amount of the lever, that is, the operating angle の of the lever.
12 are attached. As the detector 12, for example, a potentiometer is used. The operation angle ψ detected by the detector 12 is also applied to the CPU 22 of the controller 20 via the input interface 21 of the controller 20, like the rotation angles α, β, and γ.

When the operating levers 10 and 11 are operated, the respective spools of the arm operating valve 13 and the bucket operating valve 14 are moved in accordance with the respective operating amounts, and the speeds corresponding to the respective operating amounts are controlled by the operating valves 13 and 14. Arm cylinder 5 and baguette cylinder 6
Are expanded or contracted, respectively. That is, as a result of the extension and contraction operation, the rotation angles β and γ of the arm 2 and the bucket 3 change, respectively.
Also changes in the vertical direction y.

On the other hand, an operation panel 40 is provided in the driver's seat of the hydraulic excavator PS. The panel 40 includes a depth setting device 41 and an automatic mode switch 42 described later.

The automatic mode switch 42 is a switch for selecting whether to extend or retract the boom cylinder 4 manually or automatically. When the switch 42 is not pressed, that is, when the boom 1 is rotated by a manual operation of the operator, a “manual” signal of the automatic mode switch 42 is input to the CPU 22 via the input interface 21. As a result, the CPU 22 determines “manual”,
The manual automatic switching valve 15 of the hydraulic system of the boom cylinder 4 is switched to the manual side via the driver 23.

In this case, when the boom operation lever (not shown) is manually operated, the arm switching valve 13,
A spool of a boom operation valve (not shown) similar to the bucket operation valve 14 is moved, and the boom cylinder 4 is extended or retracted at a speed corresponding to the operation amount by the boom operation valve. That is, as a result of the retracting operation, the rotation angle α of the boom 1 changes, and the vertical component y of the tip position D of the bucket 3 changes in accordance with the change.

Accordingly, when the operator operates the automatic mode switch 42 of the operation panel 40 to the “manual” side, the operator operates the boom operation lever, the arm operation lever 10 and the bucket operation lever 11 in a complex 3, the vertical component y of the tip position D, ie, the bucket edge depth y
It is possible to perform a straight excavation while holding the drill at a desired position.

On the other hand, when the automatic mode switch 42 is pressed, or when the automatic mode switch 42 is operated to the "auto" side, the "auto" signal of the automatic mode switch 42 is input to the input interface.
It is input to the CPU 22 via 21. As a result, the CPU 22 determines "automatic" and switches the manual automatic switching valve 15 of the hydraulic system of the boom cylinder 4 to the automatic side via the driver 23.

In this case, the boom cylinder 4 is extended and contracted by a boom control valve (electromagnetic proportional control valve) 16 irrespective of the operation of the boom operation lever.

In the depth setting device 41, the target value Y of the cutting edge depth of the bucket 3 is set.
Is set. The signal indicating the target value Y is input to the CPU 22 via the input interface 21.

When the automatic mode switch 42 is operated to the "automatic" side, the output の of the lever angle detector 12, the outputs α, β and γ of the rotation angle detectors 7, 8 and 9 and the depth setting Based on the set value Y of the vessel 41, the controller 20 executes a calculation process described later. Based on the calculation process, the operation command signal i for holding the cutting edge depth of the bucket 3 at the set value Y is transmitted to the boom control. Will be added to the solenoid of valve 16.

In this case, as the operator, the arm operating lever
By simply operating only 10, a straight excavation operation can be performed in which the cutting edge depth of the bucket 3 is kept constant.

Next, a process performed by the controller 20 when the automatic mode switch 42 is operated to the "automatic" side will be described mainly with reference to FIGS. 1 and 2 together.

In the embodiment, it is assumed that the bucket operation lever 11 is in a neutral state.

In the arm tip full length calculation circuit 24 shown in FIG. 1, based on the current rotation angle γ of the bucket 3 to be output from the bucket angle detector 9 calculates the current arm tip overall length L ₂ from the equation (1) Processing is performed. Here, the lever 11 is the neutral state, gamma since a constant value, the total length L ₂ becomes a constant value.

On the other hand, in the arm blade full length calculation circuit 25, based on the current rotation angles β and γ of the arm 2 and the bucket 3 output from the arm angle detector 8 and the bucket angle detector 9, respectively, Processing for calculating the current arm tip angle β ₀ is performed. Here, since the total length L ₂ and the angle γ are constant values, the second term on the right side of the equation (2) is a constant value. Accordingly, the arm tip angle β ₀ is a value obtained by adding a constant value to the current rotation angle β of the arm 2.

Therefore, each output L ₂ , β ₀ of the arm blade tip full length calculation circuit 24 and the arm blade tip angle calculation circuit 25 is uniquely determined only by the operation of the arm operation lever 10 (only the arm rotation angle β).

On the other hand, the lever angle detector 12
In the detected current lever operation angle [psi, the arm cylinder estimated speed calculation circuit 26, calculating an arm cylinder estimated speed _A corresponding to the detected value [psi by the following formula (3) is performed, the estimated speed _A is Arm link correction circuit
Output to 27.

Here, the estimated arm cylinder speed _A is the speed of the arm cylinder 5 that will reach if the arm operating lever 10 is currently operated at the lever angle ψ. Furthermore, when the operating lever 10 is quickly operated to the predetermined lever angle ψ, the speed of the arm cylinder 5 does not immediately reach _A. The speed _A will eventually reach the speed _A with a slight time delay. This delay is caused by the characteristics of the hydraulic system. In the arithmetic circuit 26, the arm cylinder estimated speed _A corresponding to the current lever angle ψ is output in the correspondence shown by the following equation (3).

_A = f ₁ (ψ) (3) (see FIG. 2A) Here, the function f ₁ is a function uniquely determined by the hydraulic system of the arm cylinder 5, and FIG. Has the characteristics shown in FIG.

Next, in the arm link correction circuit 27, based on the arm cylinder estimated speed _A output from the arm cylinder estimated speed calculation circuit 26 and the current detection value β of the arm angle detector 8, the rotation angle β and the estimated Speed _A
Calculate the rotational angular velocity β of the arm 2 corresponding to Rotation angular velocity obtained by Is added to the boom speed calculation circuit 28.

Function f ₂ in equation (4) is a function uniquely determined by the link structure of the arm 2 has a characteristic as shown in FIG. 2 (b).

And the above rotational angular velocity Is the rotational angular velocity of the arm 2 when the arm cylinder 5 is operating at the estimated velocity _A and the arm rotational angle is β.

Next, in the boom speed calculation circuit 28, the arm rotation angular velocity output from the arm link correction circuit 27 is used. And the current rotation angle of the boom 1 that is output from the arm tip overall length L ₂ and the arms included angle beta ₀ is outputted from the arm tip angle calculation circuit 25 and the boom angle detector 7 is output from the arm tip full length calculation circuit 24 alpha Arm rotation angular velocity based on Angular velocity of boom 1 corresponding to Is Is calculated, and the calculated rotational angular velocity is calculated. Is output to the addition circuit 33 described later.

Here is the rotational angular velocity Means that the arm 2 has a rotational angular velocity Is the rotational angular velocity of the boom 1 required to maintain the cutting edge depth y of the bucket 3 that changes by rotating. Furthermore, the arm 2 has a rotational angular velocity And the boom 1 rotates , The blade edge depth y of the bucket 3 is kept constant.

As a result, the boom speed calculating circuit 28 determines that the rotation of the boom 1 required to maintain the cutting edge depth y of the bucket 3 when the arm operating lever 10 is constantly operated with the lever angle ψ. angular velocity Is output.

On the other hand, the depth calculation circuit 29, based on the output L ₂ and outputs beta ₀ of arms included angle calculation circuit 25 in the current rotational angle α and the arm tip full length computing circuit 24 of the boom 1 to be detected by the boom angle detector 27 The present value y of the cutting edge depth of the bucket 3 is calculated by the following formula: y = l ₁ cos α + L ₂ cos (α + β ₀ ) (6) (see FIG. 5). Added.

In the subtraction circuit 30, together with the current value y of the cutting edge depth,
The target value Y of the cutting edge depth of the bucket 3 set by the depth setting device 41 is input. Then, a deviation Δy of the blade edge depth is obtained by an operation Δy = Y−y (7), and the obtained deviation Δy is converted into a coordinate conversion circuit.
Output to 31.

Next, in the coordinate conversion circuit 31, is detected by the output beta ₀ and the boom angle detector 7 outputs L ₂ and the arm tip full length calculation circuit 25 of the deviation Δy and the arm tip full length computing circuit 24 inputted from the subtraction circuit 30 Calculate the angle deviation Δα of the boom 1 corresponding to the deviation Δy based on the current rotation angle α of the boom 1 Is added to the proportional gain multiplying circuit 32.

Here, the angle deviation Δα is an amount of angle change from the current rotation angle α of the boom 1 required to make the deviation Δy zero, that is, the current value y of the cutting edge depth of the bucket 3 to have the target value Y. . Furthermore, by changing the rotation angle α of the boom 1 by the angle deviation Δα, the cutting edge depth of the bucket 3 reaches the target value Y from the current value y.

Next, in the proportional gain multiplying circuit 32, the rotation angular velocity α ₀ of the boom 1 corresponding to the angle deviation Δα output from the coordinate conversion circuit 31 is calculated by an operation ₀ = KΔα (9). Add ₀ circuit 33
Is performed. Note that K in the above equation (9)
Is a proportional gain.

In the adder circuit 33, the rotational angular velocity output from the boom speed calculation circuit 28 And the rotational angular velocity output from the proportional gain multiplication circuit 32
Addition of rotation angular velocity command value for boom 1 based on ₀ The calculated angular velocity command value is added to the boom link correction circuit 34.

Next, in the boom link correction circuit 34, the addition circuit 33
And the boom cylinder 4 corresponding to the rotation angle α and the rotation angle speed command value α, based on the rotation angle speed command value output from the controller and the current rotation angle α of the boom 1 detected by the boom angle detector 7. Flow command value V _B ,
That calculates the speed command value for the boom cylinder 4 V _B = / f ₃ determined by (α) ...... (11) (FIG. 2 (c) see), the flow rate command value V _B obtained in the control amplifier 35 Add.

Function f ₃ wherein in (11) is a function uniquely determined by the link structure of the boom 1 in the same manner as the function f _2, and has a characteristic as shown in FIG. 2 (c) . Then, the aforementioned flow rate command value V _B, have the boom 1 is operated at a rotation angular velocity, is an operation speed of the boom cylinder 4 when a boom rotation angle alpha. Conversely, if the rotation angle of the boom cylinder 4 is not operating at a speed V _B boom 1 is α, the boom 1 will be rotated with the rotational angular velocity.

Next, the control amplifier 35, a boom link correction circuit 34 into a predetermined driving current i for adding the flow rate command value V _B output to the solenoid of the boom control valve 16 from the solenoid to the drive conversion current i Add to

As a result, the boom control valve 16 is the drive current i, i.e. extending and retracting operation of the boom cylinder 4 at a speed corresponding to the flow rate command value V _B. Then, the cutting edge depth of the bucket 3 matches the target value Y set by the depth setting device 41.

As described above, according to the embodiment, when the arm operation lever 10 is operated at the predetermined operation angle ψ, the arm operation valve 13
The arm cylinder 5 expands and contracts via the arm, and the arm 2 is rotated. At the same time, according to the operating angle の of the arm operating lever 10, the rotation angular velocity of the boom 1 for holding the cutting edge depth of the bucket 3, that is, for reducing the change in the cutting edge depth to zero. Predict. On the other hand, the rotational angular velocity _{0 of the} boom 1 required to make the deviation Δy between the current value y of the cutting edge depth of the bucket 3 and the target value Y _zero is calculated. Then, the rotational angular velocity predicted based on the operation amount of the arm operation lever 10 Angular velocity according to the deviation Δy of the blade edge depth of the bucket 3 and the bucket 3
_The flow rate command value corresponding to the rotation angular velocity obtained by adding ₀ is given to the boom cylinder 4.

Here, conventionally, the flow command value according to the deviation between the current value of the cutting edge depth of the bucket 3 and the target value is simply given to the boom cylinder 4. In this case, when the arm operation lever 10 is operated, the arm 2 rotates with a response delay. While the arm 2 is rotating, a flow command value is given to the boom cylinder 4 in accordance with the deviation on one side, and the boom 1 rotates, but the boom rotates in response to the boom flow command. When the boom 1 is rotated in accordance with the flow rate command value, the rotation angle of the arm 2 has already reached a different rotation angle. It was extremely difficult. In particular, when the arm operating lever 10 is suddenly operated, the accuracy of the control of the cutting edge depth is further deteriorated. However, according to the embodiment, when the arm operation lever 10 is operated, the bucket 3 is operated in accordance with the operation amount.
The rotation angular velocity of the boom 1 for maintaining the current cutting edge depth is estimated, and the flow command value corresponding to the rotation angular speed is added to the flow command value corresponding to the deviation of the cutting edge depth. Therefore, it is possible to improve deterioration of the accuracy of the control of the cutting edge depth due to the response delay.

In the embodiment, the estimated speed _A of the arm cylinder 4 and the arm 2
Accurate rotational angular velocity of arm 2 according to rotational angle β Is calculated. In the boom speed calculation circuit 28, the accurate rotational angular speed of the arm 2 is calculated. Rotation speed of the boom 1 required to maintain the cutting edge depth y of the bucket 3 at the current state based on the Will be obtained accurately.

In the boom link correction circuit 34, the rotation angular velocity _{0 of the} boom 1 required to make the deviation Δy of the cutting edge depth of the bucket 3 _zero and the accurate rotation angular velocity of the boom 1 And the accurate boom 1 flow rate command value according to the boom 1 rotation angular velocity α.
V _B will be calculated.

Therefore, in the related art, since the deviation Δy of the bucket edge depth is used as the flow command value to be directly given to the boom cylinder, the bucket edge depth Y may be accurately determined depending on the values of the rotation angles α and β of the boom 1 and the arm 2. , But according to the embodiment, these rotation angles α,
The exact flow rate command value V _B corresponding to β is calculated, so that the boom cylinder 4 is actuated in response to the exact flow rate command value V _B. Therefore, the bucket edge depth y exactly matches the target value Y.

In the embodiment, an example in which the present invention is applied to a working machine including three elements of a boom, an arm, and a bucket has been described. However, the present invention is not limited thereto. Needless to say, the present invention can be applied to a working machine having the same.

Further, in the embodiment, an example in which the present invention is applied to a hydraulic excavator has been described. However, the present invention is not limited to this. For example, a construction machine that performs work while maintaining the blade edge depth of a bucket such as a backhoe constant. If so, its application and implementation are of course possible.

〔The invention's effect〕

As described above, according to the present invention, not only the current value and the target value of the bucket cutting edge depth, but also the bucket cutting edge depth is controlled based on the deviation considering the predicted change amount of the arm. Control responsiveness is improved. Further, the boom is rotated by an optimum command corresponding to the rotation angle of the boom and the arm. As a result, it is possible to accurately and stably match the cutting edge depth of the bucket to a desired target value, so that the operation speed is improved and the operation can be performed accurately and stably. .

[Brief description of the drawings]

FIG. 1 is a control block diagram showing one embodiment of a bucket cutting edge depth control device for a construction machine according to the present invention, and FIGS. 2 (a), (b) and (c) are booms shown in FIG. FIG. 3 is a graph used to explain the arithmetic processing performed by the cylinder estimation speed arithmetic circuit, the arm ring correction circuit, and the boom link correction circuit. FIG. 3 is a block diagram conceptually showing the overall configuration of the embodiment. The figure is a side view showing the configuration of the working machine of the hydraulic excavator in the embodiment,
FIG. 5 is a graph showing a geometric relationship of each element of the work machine shown in FIG. PS hydraulic excavator, 1 boom, 2 arm, 3 bucket, 4 boom cylinder, 5 arm cylinder, 6 bucket cylinder, 7 boom angle detector, 8 … Arm angle detector, 9… bucket angle detector, 10 …… arm operating lever, 11 …… bucket operating lever, 12 …… lever angle detector, 13 …… arm operating valve, 14 …… bucket operating valve, 16 ... boom control valve (electromagnetic proportional control valve), 20 ... controller, 24 ... arm blade full length circuit, 25 ... arm blade angle calculation circuit, 26 ... arm cylinder estimated speed calculation circuit, 27 ... arm link Correction circuit, 28 Boom speed calculation circuit, 29 Depth calculation circuit
30 subtraction circuit, 31 coordinate transformation circuit, 32 proportional gain multiplication circuit, 33 addition circuit, 34 boom link correction circuit, 41 depth setting device.

Claims (2)

(57) [Claims] 1. A boom rotatably attached to one point of a vehicle body and controlled by a first actuator, and an arm rotatably mounted on a tip of the boom and controlled by a second actuator. And a bucket attached to the tip of the arm and controlled to rotate by a third actuator. A rotation angle detecting means for detecting each rotation angle of the boom, the arm and the bucket; An operation amount detection unit that detects an operation amount of an arm operation lever to be operated; an arm control unit that controls the second actuator in accordance with an operation amount of the arm operation lever; an output of the rotation angle detection unit; Based on the operation amount of the arm operation lever detected by the operation amount detection means, the operation amount corresponds to the operation amount of the arm operation lever. First drive command value creation means for creating a drive command value for the first actuator that makes the change in the cutting edge depth of the bucket zero, and target value setting means for setting a target value for the cutting edge depth of the bucket Current value calculation means for calculating a current value of the cutting edge depth of the bucket based on the output of the rotation angle detection means, an output of the rotation angle detection means, a set target value of the target value setting means, A second drive command value creating means for creating a drive command value for the first actuator for making a deviation between the set target value and the current value zero based on the current value calculated by the current value calculation means; And a means for controlling the drive of the first actuator in accordance with the sum of the drive command values created by the first and second drive command value creating means, respectively. Edge depth control Apparatus. 2. A boom which is rotatably attached to one point of a vehicle body and is rotated by a boom cylinder, an arm which is rotatably mounted on a tip of the boom and is rotated by an arm cylinder, and a tip of the arm. A rotation angle detecting means for detecting each rotation angle of the boom, the arm and the bucket; and 4 an operation amount of an arm operation lever for operating the arm. Operation amount detection means for detecting the operation amount, arm control means for operating the arm cylinder at a speed corresponding to the operation amount of the arm operation lever to rotate the arm, and the arm operation detected by the operation amount detection means Arm cylinder speed calculating means for calculating a speed of the arm cylinder corresponding to the operation amount based on the operation amount of the lever; A rotation angle of the arm detected by the rotation angle detection means;
Arm rotation angular velocity calculating means for calculating a rotation angle of the arm and a rotation angular velocity of the arm corresponding to the arm cylinder velocity based on the arm cylinder velocity calculated by the arm cylinder speed calculating means; A rotation angle velocity of the boom for reducing a change in the depth of the bucket edge corresponding to the rotation angle velocity of the arm to zero based on the output of the means and the rotation angle velocity of the arm calculated by the arm rotation angular velocity calculation means. First boom rotation angular velocity calculating means for calculating a target value, a target value setting means for setting a target value of the cutting edge depth of the bucket, and a current value of a cutting edge depth of the bucket based on an output of the rotation angle detecting means. Current value calculating means for calculating the output of the rotation angle detecting means, the set target value of the target value setting means and the current value calculating means. A second boom rotation angular velocity calculating means for calculating a rotation angular velocity of the boom for reducing a deviation between the set target value and the current value to zero based on the current value thus obtained; The rotation angle of the boom,
Based on the boom rotation angular velocities calculated by the first and second boom rotation angular velocity calculation means, respectively, the sum of the boom rotation angular velocities and the boom cylinder velocity corresponding to the boom rotation angle are calculated. Boom cylinder speed calculating means, and means for operating the boom cylinder according to the boom cylinder speed calculated by the boom cylinder speed calculating means to rotate the boom. Bucket edge depth control device.