JPH083187B2 - Power shovel bucket angle controller - Google Patents

Description

The present invention relates to a bucket angle control device for a power shovel.

[Prior Art] Conventionally, a method of keeping the angle of the bucket with respect to the ground constant to move the working machine so as not to spill the load loaded on the bucket or to level the ground with the back of the bucket (ground angle There is a constant control).

[Problems to be Solved by the Invention] However, when the inclination angle of the upper swing body of the vehicle body facing the working machine changes, the constant ground angle control of the bucket is not performed.

For example, as shown in FIG. 3 (a), the position of the working machine is determined so that the load is not spilled on a sloping ground with a tilt angle ζ (boom angle is α, arm angle is β, and bucket angle is γ). As shown in FIG. 3 (b), while performing constant control of the bucket 3 with respect to the ground angle δ (α, β, γ in FIG. 3 (b) are the same as those in FIG. 3 (a)), When you turn 180 degrees,
Although the bucket body angle δ is constant, the bucket absolute angle (angle with respect to the absolute horizontal) changes, and a spillage occurs.

Also, when traveling with the bucket 3 loaded,
When the inclination of the ground changes, load spillage may occur in the bucket-to-ground constant angle control as described above.

In order to solve such a problem, in JP-A-59-52027, a device for detecting the swinging posture of the bucket with respect to the horizontal is provided, and the swinging posture of the bucket is determined based on the detection result of this detecting device. At least one of the drive swing mechanism of the arm and the drive swing mechanism of the bucket is automatically controlled so that the bucket is held in the maximum posture or a posture close to the maximum posture, so that the bucket can be moved when excavating soil by turning or moving the body. The posture is kept at the maximum acceptable amount without spilling the excavated soil or a posture close to it.

However, in this cited example, since there is no description of what corresponds to the means for setting the bucket absolute angle, the posture that the bucket can take is limited to the posture with the maximum receptive amount or a posture close thereto, and any other posture. You can't get it.

Further, in this cited example, a dedicated switch is provided to turn on / off the bucket horizontal control. However, such a switch 11 that is placed separately from the work machine operating lever is disadvantageous in terms of operability and safety.

The present invention has been made in view of such a situation,
An object of the present invention is to provide a bucket angle control device for a power shovel, which is capable of performing constant bucket absolute angle control for causing the bucket to take an arbitrary posture and is excellent in operability and safety.

[Means for Solving Problems] According to the present invention, in a power shovel having a working machine including a boom, an arm and a bucket, and a revolving superstructure of a vehicle body, angle detection for detecting a boom angle, an arm angle and a bucket angle, respectively. Means, an inclination angle detection means for detecting an inclination angle of the upper body of the vehicle body with respect to the horizontal direction with respect to the direction in which the work machine is facing, a lever neutrality detection means for detecting the time when the bucket operation lever returns to the neutral position, and this lever. Bucket absolute angle indicating means for obtaining a bucket absolute angle in absolute coordinates at the time when the neutral detection means outputs a detection signal, and indicating the obtained bucket absolute angle as a target value, detection output of the angle detecting means, and the tilt angle The bucket absolute angle calculated based on the detected tilt angle of the detection means is indicated by the bucket absolute angle instruction means. And a control means for executing control for driving the bucket cylinder so as to match the bucket absolute angle from the time when the lever neutrality detection means outputs a detection signal.

[Operation] According to the invention, when the bucket operation lever is returned to the neutral position during bucket operation by the bucket operation lever, even if the vehicle body tilt angle, boom angle, arm angle, etc. change thereafter, It operates to hold the bucket's absolute angle.

EXAMPLES The present invention will be described in detail below with reference to the accompanying drawings.

FIG. 2 schematically shows each of the working machines of the boom 1, the arm 2, and the bucket 3 of the power shovel, and shows the case where the revolving superstructure on the upper part of the power shovel body is inclined by the angle ζ due to the inclination of the ground. ing. That is, in the figure, when the coordinates of the plane including the working machines having the horizontal direction as the X axis and the vertical direction as the Y axis are absolute coordinates, the vehicle body coordinates are relative to the absolute coordinates due to the tilt angle ζ of the swing structure. It is rotating by the angle ζ.

Further, an angle α formed between the Y axis of the vehicle body coordinates and the boom 1 is a boom angle, an angle β formed between the boom 1 and the arm 2 is an arm angle, and an angle γ formed between the arm 2 and the bucket 3 is a bucket angle. The soot angle θ between the line segment between the pin C and the bucket blade point and the absolute horizontal is the bucket absolute angle θ.

From FIG. 2, the bucket absolute angle θ can be expressed by the following equation, θ = 3π / 2 (α + β + γ + ζ) (1), using the boom angle α, the arm angle β, the bucket angle γ, and the inclination angle ζ.

Therefore, by controlling the bucket angle γ based on the above (1), the bucket absolute angle θ is set to the boom angle α,
The control can always be made constant regardless of the arm angle β and the inclination angle ζ.

Now, the control target angle γ ^ref of the bucket angle for keeping the bucket absolute angle θ constant will be as follows. That is, the target bucket absolute angle θ is θ ₀ ,
Let the angles at that time be α ₀ , β ₀ , γ ₀ , ζ ₀ , respectively, and let the respective angles at the time of controlling the target be θ,
Assuming α, β, γ, ζ, the deviation Δθ is calculated by the following equation: Δθ = θ ₀ −θ = 3π / 2 (α ₀ + β ₀ + γ ₀ + ζ ₀ ) − {3π / 2 (α + β + γ + ζ)} ... (2 ). Here, since the bucket absolute angle θ is controlled to be constant, if Δθ = 0 in the above (2) and the bucket angle γ is rearranged, γ = α ₀ + β ₀ + γ ₀ + ζ ₀ − (α + β + ζ) ... ( 3) This bucket angle γ is the bucket angle target angle γ
^{If the} bucket is rotationally controlled as ^ref , constant control of the bucket absolute angle can be performed.

FIG. 1 is a block diagram showing an embodiment of the present invention, which is an embodiment of an apparatus for switching between conventional bucket control by lever operation and control for keeping the absolute angle of a bucket constant according to the present invention.

In the figure, the electric lever 10 outputs a signal indicating the bucket rotation speed ^ref corresponding to the lever tilt amount to the integrator 11 and the speed command zero detection circuit 12. The electric lever
When you let go of 10, the lever returns to its neutral position, ^ref =
A signal indicating 0 is output.

The integrator 11 time-integrates an input signal indicating the bucket rotation speed ^ref, and outputs the integrated value, that is, a signal indicating the target angle γ ^ref of the bucket angle, to the contact 13a of the changeover switch 13.

The speed command zero detection circuit 13 has a bucket rotation speed ^ref of 0.
When ^ref = 0, the signal "1" is applied to the changeover switch 13 and the movable contact piece 13c of the changeover switch 13 is connected to the contact 13c to switch to the bucket absolute angle constant control. ^{When ref} ≠ 0, the operator gives a command to move the bucket. Therefore, the signal "0" is applied to the changeover switch 13, and the movable contact piece 13c of the changeover switch is connected to the contact 13a to control the bucket by lever operation. Switch to.

The differentiator 14 takes a rise differentiation of the signal applied from the speed command zero detection circuit 12, and latches the signal (pulse signal) at the first time point when the bucket rotation speed ^ref becomes zero.
Is output to the latch circuit 15.

The data of the latch circuit 15 is input to the tilt angle detector 16, the boom angle detector 17, the arm angle detector 18 and the bucket angle detector 19 from the tilt angle ζ, the boom angle α, and the arm angle, respectively, as shown in FIG. β and bucket angle γ are added. Here, the tilt angle detector 16 is arranged on the upper revolving structure 4 so as to detect the tilt angle in the direction in which the working machine is facing, and a pendulum type inclinometer can be considered, for example. Of course,
The inclination angle detector 16 detects the inclination angle (ζ) in the illustrated state, but when the upper revolving structure 4 turns 180 ° from this state, it detects the inclination angle (−ζ).

When the latch signal is applied from the differentiator 14 to the latch circuit 15,
The signals indicating the angles ζ, α, β, γ applied from the detectors 16 to 19 are latched, and these are added to the adder 20 as angles ζ ₀ , α ₀ , β ₀ , γ ₀ until the latch signals are applied again. Adder
20 adds the signals applied from the latch circuit 15 and adds a signal indicating the added value (α ₀ + β ₀ + γ ₀ + ζ ₀ ) to the positive input of the addition point 21.

The adder 22 adds the signals indicating the angles ζ, α, and β added from the tilt angle detector 16, the boom angle detector 17, and the arm angle detector 18, and adds a signal indicating the added value (α + β + ζ) to the addition point 21. Add to the negative input of.

At the addition point 21, two input signals are added, and the added value, that is, the bucket angle γ for performing the bucket absolute angle constant control.
A signal indicating ^ref (see the expression (3)) is output to the contact 13b of the changeover switch 13.

The changeover switch 13 is a speed command zero detection circuit as described above.
The movable contact piece 13c is switched by the output of 12, and a signal indicating either the target angle γ ^ref related to the bucket control by lever operation or the target angle γ ^ref related to the constant bucket absolute angle control is added to the addition point 23. Select and output.
The feedback amount indicating the actual bucket angle γ of the bucket 3 from the bucket angle detector 19 is added to the other input of the addition point 23.

At the addition point 23, the deviation between the bucket target angle γ ^ref and the actual bucket angle γ is taken, and this deviation signal promptly cancels this deviation, and proportional / integral / derivative compensation, etc. are performed so that stable control is performed. Is added to the flow control valve 25 via a compensator 24 for

The flow control valve 25 supplies the pressure oil having a flow rate according to the input signal to the bucket cylinder 5. As a result, the bucket 3 is rotationally controlled so as to have the target angle γ ^ref .

In the present embodiment, the bucket absolute angle of the actual machine at the first time when the electric lever 10 is no longer operated is set as the target bucket absolute angle, and this is held constant, but the bucket absolute angle is indicated. The means for doing so is not limited to this, and for example, setting means for directly setting the bucket absolute angle may be provided to keep the set bucket absolute angle constant.

Further, in this embodiment, the changeover switch 13 is automatically changed over depending on whether or not the electric lever 10 is operated, but this changeover may be performed manually.

[Effects of the Invention] As described above, according to the present invention, when performing the bucket absolute angle constant control, the bucket angle can be set to an arbitrary angle, and not only the bucket horizontal control but also the pile driving work, the slope excavation, and the like. It can be applied to various types of work. Further, when carrying out the bucket absolute angle constant control, the operator only needs to perform an extremely simple operation of returning the bucket operation lever to the neutral position when the bucket attitude is in an appropriate state while operating the bucket operation lever, and In this case, the operator does not have to release his / her hand from the bucket control lever, which is advantageous in terms of operability and safety compared to the method of numerically setting the angle with a dial or the method of instructing the control on / off by another switch. There is also an advantage that work efficiency is improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing angles of respective parts of a working machine of a power shovel used for explaining the present invention, FIGS. 3 (a) and (a). FIG. 2B) is a schematic view of a power shovel used to explain conventional problems. 1 ... Boom, 2 ... Arm, 3 ... Bucket, 4 ...
Upper revolving structure, 5 …… bucket cylinder, 10 …… electric lever, 11 …… integrator, 12 …… speed indication zero detection circuit, 13 ……
Changeover switch, 14 ... Differentiator, 15 ... Latch circuit, 16 ...
… Inclination angle detector, 17 …… Boom angle detector, 18 …… Arm angle detector, 19 …… Bucket angle detector, 20,22 …… Adder, 24 …… Compensator, 25 …… Flow control valve .

Continuation of front page (56) References JP-A-59-52027 (JP, A) JP-A-61-270421 (JP, A) JP-A-60-133126 (JP, A)

Claims (1)

[Claims] 1. In a power shovel having a working machine composed of a boom, an arm and a bucket, and a revolving superstructure of a vehicle body, the angle detecting means for respectively detecting the boom angle, the arm angle and the bucket angle are facing the working machine. The inclination angle detection means for detecting the inclination angle with respect to the vehicle upper body swing structure, the lever neutrality detection means for detecting the time when the bucket operation lever returns to the neutral position, and the lever neutrality detection means for detecting the time when the lever neutrality detection means outputs the detection signal. The bucket absolute angle is obtained in absolute coordinates, and is calculated based on the bucket absolute angle instruction means for instructing the obtained bucket absolute angle as a target value, the detection output of the angle detection means, and the inclination angle detected by the inclination angle detection means. The bucket absolute angle to match the bucket absolute angle designated by the bucket absolute angle designating means. Excavators bucket angle control device with a control means for executing control to drive the Ttoshirinda from the time when the lever neutral detecting means outputs a detection signal.