JPH0663249B2 - Control device for power shovel - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention is applied to a power shovel having a first boom and a second boom, and an arm having a structure rotatable about its longitudinal axis. Control device.

[Prior Art] In this type of power shovel, an arm is rotatable about its longitudinal axis, and therefore the arm is rotated to orient the blade edge of the bucket laterally, and then the upper swing body is swung. This allows so-called side digging.

[Problems to be Solved by the Invention] By the way, in the case of performing the above-mentioned horizontal excavation to form a straight groove, it is necessary to keep the blade edge direction of the bucket constant. Changes with the turning of. Therefore, conventionally, an operation of rotating the arm around the longitudinal axis was performed to correct the change in the blade edge direction.However, since such a correction operation is performed simultaneously with the swing operation of the upper swing body and the boom operation, This imposes a heavy burden on the operator and reduces the work efficiency.

In view of such a situation, the present invention aims to reduce the labor of an operator and to improve the efficiency of excavation work.

[Means for Solving Problems] According to the present invention, an angle detecting means for detecting a turning angle of an upper swing body and a difference between an initial angle and a current angle of the swing body based on an output of the angle detecting means. Along with the determination, a control means for rotating the arm in the direction opposite to the swing direction of the upper swing body by this angular difference is provided, thereby achieving the above object.

[Operation] According to the above configuration, the arm is rotated such that the blade edge direction of the bucket is always directed in a predetermined direction.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of a control device according to the present invention, and FIG. 2 shows the configuration and working mode of a power shovel to which this control device is applied.

The power shovel shown in FIG. 2 includes a first boom 1, a second boom 2, an arm 3 and a bucket 4, and the arm 3 is a third boom.
This base is supported on the tip of the second boom 2 so that it can rotate about the longitudinal axis 1 shown.

Further, as shown in FIG. 3, the attitude angles φ ₁ , φ ₂ , φ ₃ and the turning angle β of the first boom 1, the second boom 2, the arm 3 and the upper swing body 5 are detected. Potentiometers 6, 7, 8 and 9 are provided respectively, and a potentiometer 10 for detecting the rotation angle α is provided at the base of the arm 3.

A hydraulic motor 34 for rotating the arm is provided at the base of the arm 3.
Is provided.

The first boom 1, the second boom 2, the arm 3 and the bucket 4 are swiveled by the first boom cylinder 11, the second boom cylinder 12, the arm cylinder 13 and the bucket cylinder 14 shown in FIG. 2, respectively.

FIG. 4 is a plan view showing the inside of the driver's seat provided on the upper swing body 5. In this driver's seat, two levers 15 and 16 which can be operated in the front and rear and left and right and four pedals 17 to 20 are arranged.

The longitudinal operating force of the lever 15 is transmitted to the switching valve 21 shown in FIG. The switching valve 21 has a function of applying its output pressure as a pilot pressure to the operation valve 22 for operating the upper swing body. Therefore, by operating the lever 15 in the front-rear direction, the upper swing is performed at a speed corresponding to the operation amount. The body driving hydraulic motor 23 is rotated forward and backward.

Also, the operating force in the left-right direction of the lever 15 is transmitted to the switching valve 24 shown in FIG. 1, whereby the output pressure of the switching valve 24 is piloted to the arm operating valve 26 via the shuttle valves 25A and 25B. Applied as pressure. Therefore, the lever 15
When is operated in the left-right direction, the arm cylinder 13 is expanded and contracted at a speed corresponding to the operation amount. That attitude angle φ ₃ of the arm 3 is changed.

The operating force of the lever 16 in the front-back direction is the switching valve shown in FIG.
27, and the output pressure of the switching valve 27 is applied as a pilot pressure to the first boom operating valve 28.
Therefore, by operating the lever 16 in the front-back direction, the first boom cylinder 11 is moved at a speed corresponding to the operation amount.
Is expanded and contracted. That is, the attitude angle φ ₁ of the first boom is changed.

The operating force of the lever 16 in the left-right direction is transmitted to a switching valve (not shown), whereby the bucket operating valve (not shown) is piloted by the output pressure of the valve to operate the bucket.

On the other hand, the movement of the pedal 17 is transmitted to the potentiometer 29 shown in FIG. With this, the potentiometer 29 has a polarity corresponding to the stepping direction of the pedal,
A signal having a value corresponding to the stepping amount is output, and this signal is input to the controller 30.

Then, when the left end of the pedal 17 is stepped on, a signal is supplied to the arm left rotation support valve 31, and when the right end is stepped on, the arm left rotation servo valve 32 is supplied with a signal,
Along with this, pilot pressure from the valves 31 and 32 is applied to the arm rotation operation valve 33. Therefore, the stepping operation of the pedal 17 actuates the arm rotation motor 34, whereby the arm 3 is rotated about the axis l.

The movement of the pedal 20 is transmitted to the switching valve 35 shown in FIG. The output pressure of the valve 35 is the operation valve 36 for operating the second boom.
Since it acts as a pilot pressure on the second boom cylinder 12, when the pedal 20 is stepped forward and backward, the second boom cylinder 12 is expanded and contracted at a speed corresponding to the stepped amount.

The pedals 18 and 19 are operated when changing the traveling direction and traveling speed of the left traveling system and the right traveling system, respectively.

FIG. 5 shows the internal structure of the grip portion 161 of the lever 16. This grip portion 161 is a lower grip member 1
62, an upper grip member 163 slidably fitted to the lower grip member 162, a micro switch 164 arranged in the member 162, and a push button switch 165 arranged on the top of the member 163. Has been done.

In this grip portion 161, the micro switch 164
Is closed when the upper grip member 163 is slid downward against a spring (not shown). The push button switch 165 is set by the first action and
It has the function to be reset by action eyes.

Next, the principle of the present invention will be described. In FIG. 7, the solid line shows the state where the rotation angle of the arm 3 is α = −60 ° and the swing angle of the upper swing body 5 is β = 60 °.

Now, as shown by the alternate long and short dash line in the figure, when the revolving unit 5 is turned right by 30 °, the direction of the blade edge of the bucket 4 is at this turning angle 30.
Change only by °. The figure shows the swing angle of the upper swing structure 5.
It is shown that if the arm 3 is rotated in the opposite direction to the revolving structure by 30 °, the bucket blade tip direction before revolving and that after revolving coincide.

The present invention performs control to hold the bucket blade tip direction in the initial direction based on such consideration.
The operation of this embodiment will be described with reference to FIG. 6 showing the processing procedure of the controller 30.

In the controller 30 to which the output signals of the potentiometers 6 to 10, the micro switch 164 and the push button switch 165 are added, first, at step 200, the switch 165
Is in the ON state, that is, whether the automatic mode is selected. If the result of the determination is NO, the flag F is set to "0" (step 201).

When the switch 165 is pressed and the result of the determination in step 200 becomes YES, it is determined whether or not the flag F is "0" (step 202). Since F = "0" at present, In step 203, the initial rotation angle α of the arm 3 and the initial rotation angle β of the upper swing body 5 are input and stored. Incidentally, these angles α and β are detected based on the outputs of the potentiometers 10 and 9, and α = −60 ° and β = 60 ° in the example shown in FIG.

In the next step 204, the process of setting the flag F to "1" is executed, and then the current swing angles α'and β'of the arm 3 and the upper swing body 5 are input (step
205). Then, in step 206, A = α + β, A ′ = α ′
The calculation of + β 'is executed, and the calculation of the difference ΔA = A'-A between the calculation results is executed.

The difference ΔA indicates a deviation angle between the initial blade edge direction of the bucket 4 and the blade edge direction at the present time. In the next step 207, it is determined whether or not this value ΔA is 0.

If the determination result in step 207 is NO, the procedure jumps to step 211 described later, and the determination result is YES.
In the case of, the next step 208 judges whether the value ΔA is positive or negative. If the determination result in step 208 is YES, a control signal corresponding to the value | ΔA | is applied to the arm left rotation servo valve 31 (step 209), and if NO, the control signal is output to the arm. It is added to the right rotation servo valve 31 (step 210).

In the next step 211, it is judged whether or not the micro switch 164 provided in the grip portion 161 is operated (step 211). Since the judgment result is NO at this moment, the process returns to step 200.

Thus, according to this embodiment, the rotation angle of the arm 3 is automatically controlled so that the bucket blade edge is directed in the initial direction (direction based on the initial rotation angle of the arm 3) regardless of the rotation angle of the revolving structure 5. . Therefore, when performing horizontal straight line excavation as shown in FIG. 8, it is not necessary to rotate the arm 3.

After the initial rotation angle of the arm and the initial rotation angle of the upper swing body 5 are input, the flag F is in the "1" state, so the procedure of the controller 30 jumps from step 202 to 205 and the current arm The rotation angle α'and the swing structure swing angle β'are input.

Further, in the above embodiment, the position deviation ΔA shown in step 206 of FIG. 6 is calculated, and the bucket blade edge is directed in the initial direction by rotating the arm 3 in the direction in which the deviation ΔA becomes zero. Even if the longitudinal operation amount of the lever 15 shown in FIG. 4, that is, the turning angular velocity of the upper swing body 5 is detected and the arm 3 is rotated in the opposite direction to the swing body 5 at an angular velocity equal to this angular velocity, Similar to the above, it is possible to point the bucket blade in the initial direction.

Next, the case where the grip member 163 of the grip portion 161 is slid to turn on the micro switch 164, that is, the determination result of step 211 is YES will be described.

In this case, the attitude angles φ ₁ , φ ₂ and φ _{3 of} the first boom 1, the second boom 2 and the arm 3 are input to the controller 30 based on the outputs of the potentiometers 6, 7 and 8 (step 212), Then θ = 2π−φ ₁ −φ ₂ −φ
_The calculation of ₃ and the calculation of Δθ = θ−θr are executed (step 213).

As is clear from FIG. 3, when the posture angle of the arm 3 with respect to the angle reference axis (horizontal axis) of the first boom 1 is θ,
_{Since the} relation of ₁ + φ ₂ + φ ₃ + θ = 2π is established, the posture angle θ is represented as θ = 2π−φ ₁ −φ ₂ −φ ₃ . Therefore, in step 202, the current posture angle θ of the arm 3 and the deviation Δ between the posture angle θ and the target posture angle θr are calculated.
θ will be obtained.

When the angle deviation Δθ is obtained, it is determined in the next step 214 whether or not the angle deviation Δθ is zero. When it is determined that Δθ = 0, step 200
And it is judged that Δθ ≠ 0 (step 21
Five).

Then, if the determination result of step 215 is YES, the control signal corresponding to the angular deviation | Δθ | is added to the servo valve 37 (step 216), and if the determination result is NO, similar control is performed. The signal is applied to the servo valve 38 (step
217).

The output pressure of the servo valve 37 acts as a pilot pressure for extending the arm cylinder on the arm operating valve 26 via the shuttle valve 25A, and the output pressure of the servo valve 38 is the shuttle valve.
It acts on the operation valve 26 as a pilot pressure for retracting the arm cylinder via 25B. As a result, the posture angle θ of the arm 3
Is θ> θr, the arm cylinder 13 is extended and θ
Control is performed such that the cylinder 13 is retracted when <θr, and thereby the posture angle θ of the arm 3 is held at the target posture angle θr.

By executing the procedure shown in steps 212 to 217, the following advantages can be obtained. That is, when performing lateral straight excavation as shown in FIG. 8, since the operation of the first boom 1 and the second boom 2 is accompanied in order to adjust the reach length of the working machine, this boom is used. It is necessary to correct the change in the attitude angle of the arm due to the operation of. However,
By performing the above procedure, the swing angle φ of each boom 1, 2
The posture angle of the arm 3 is always the target posture angle θ regardless of ₁ and φ _2.
Since it is held at r, the posture angle correcting operation of the arm is not necessary.

The target posture angle θr is usually set to 90 °. The setting device 40 shown in FIG. 1 is provided to set this target posture angle.

By the way, in order to switch the automatic mode to the manual mode, the push button switch 165 may be pressed again.However, if the manual interruption of the arm rotation during the operation in the automatic mode can be applied, the arm can be tensioned in an emergency. This is convenient when rotating 3 or when temporarily correcting the arm rotation angle.

To enable the above manual interrupt, the controller 30
The manual operation priority function may be added to. That is, when the pedal 17 shown in FIG. 4 is operated in the automatic mode, the control signal output in steps 216 and 217 is cut, and the output of the potentiometer 29 shown in FIG. 1 is replaced with this control signal. The controller 30 has the function of applying a manual control signal based on
Can be added to.

Further, it is desirable that a manual interruption of the posture angle of the arm can be made even during the automatic control for holding the arm at the target angle θr.

The shuttle valve 41 and the pressure switch 42 shown in FIG. 1 are provided in consideration of this point. Now, when the switching valve 24 is manually switched from the neutral position while the automatic mode is selected, the output pressure of one or the other output port of the valve 24 is applied to the pressure switch 42 via the shuttle valve 41. Therefore, the pressure switch is turned on. That is, it is possible to detect that the switching valve 24 is manually operated from the output of the pressure switch 42.

Therefore, if the controller 30 is caused to perform a process of cutting the control signals for the servo valves 37 and 38 based on the ON signal of the pressure switch 42, the automatic control of the arm cylinder 13 is interrupted and the same cylinder is manually operated. Can be controlled.

[Effects of the Invention] As is clear from the above-described embodiments, according to the present invention, the blade edge direction of the bucket can be held constant regardless of the turning angle of the upper-part turning body. Therefore, it is possible to reduce the labor of the operator and improve the efficiency of the work because the arm does not need to be rotated.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a power shovel control device according to the present invention, and FIG. 2 is a perspective view showing a configuration of a power shovel to which the present invention is applied and an excavation mode thereof.
FIG. 3 is a conceptual diagram showing the relationship between the posture angles of the first boom, the second boom, and the arm and the posture angle of the arm. FIG. 4 is a plan view conceptually showing the configuration of the driver's seat. FIG. 6 is a conceptual diagram illustrating the configuration of the grip portion of the lever, FIG. 6 is a flowchart showing the processing means of the controller shown in FIG. 1,
FIG. 7 and FIG. 8 are conceptual diagrams showing the operation mode of the power shovel when the control device shown in FIG. 1 is used. 1 ... 1st boom, 2 ... 2nd boom, 3 ... arm,
4 ... Bucket, 5 ... Upper revolving structure, 6-10,29 ... Potentiometer, 11 ... First boom cylinder, 12 ... Second boom cylinder, 13 ... Arm cylinder, 5,16 ... Lever, 17-20 …… Pedal, 164 …… Micro switch, 1
65 …… Push button switch, 21,22,27,35 …… Switching valve, 30 ……
Controller, 31, 32, 37, 38 ... Servo valve.

Claims (1)

[Claims] 1. A control device applied to a power shovel having a first boom and a second boom and having an arm rotatable about its longitudinal axis, the control device detecting a swing angle of an upper swing body. The angle detection means and the difference between the initial angle and the current angle of the upper swing body are obtained based on the output of the angle detection means, and the arm is rotated in the opposite direction to the upper swing body by this angle difference. A control device for a power shovel, comprising: a control means.