JPS6282128A - Bucket angle controller for power shovel - Google Patents

Abstract

PURPOSE:To keep the absoluble angle of a bucket constant, by controlling the bucket so that a bucket angle computed flow a boom angle, an arm angle, the bucket angle, and a tilt angle may coincide with the absolute angle of the bucket designated by a bucket absolute-angle designating means. CONSTITUTION:When a lever 10 is horizontally laid and is left as it as, then the lever 10 returns to a neutral position, and signal showing bucket rotational speed gamma<ref>=0 is applied to a switch 13, and the output of bucket absolute-angle constant-control command signal is generated. The bucket absolute-angle for a target is determined by a latch circuit 15, adders 20, 22, and an added point 21 from a tilt angle phi, a bboom angle alpha, an arm angle beta, and bucket angle gammadetected by respective detectors 17, 18, 19, 20. Signal for deviation between bucket target angle gamma<ref> and actual bucket angle gamma is applied to a flow rate control valve 25 from an added point 23 and the pressure-oil of adequate flow rate is fed to a bucket cylinder 5, and a bucket 3 is rotatably controlled to be set at the target angle gamma<ref>.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a bucket angle control device for a power shovel.

[Conventional Technique II] Conventionally, in order to avoid spilling the load loaded in the bucket, a method of keeping the angle of the bucket constant with respect to the ground (ground-to-ground (called constant angle control).

[Problems to be Solved by the Invention] However, when the angle of inclination in the direction in which the working machine of the heavy revolving superstructure changes, the bucket's ground angle cannot be controlled to be constant.

For example, as shown in Figure 3 (a), position the work equipment so as not to spill the load on a slope with a slope (the boom angle is α, the arm angle is β, and the bucket angle is γ), and then Third
As shown in Fig. 3 (b), while controlling the bucket 3 ground angle δ constant (in Fig. 3 (b), α, β, and γ are
Same as a)), when the upper rotating body 4 is rotated 180°,
Although the bucket body angle δ remains constant, the bucket absolute angle (angle with respect to the absolute horizontal) changes, causing cargo spillage.

Also, when traveling with the bucket 3 loaded with a load, if the slope of the ground changes, the load may break loose if the bucket-to-ground angle is controlled to be constant, as described above.

The present invention has been made in view of the above-mentioned circumstances, and is a bucket angle control system for a power shovel that can maintain the absolute bucket angle constant even if the inclination angle of the working machine on the upper rotating structure of the vehicle body changes. The purpose is to provide equipment.

[Means for Solving the Problems] According to the present invention, there is provided a bucket absolute angle indicating means for indicating the absolute bucket angle expressed in absolute coordinates, and angle detection means for detecting the boom angle, arm angle, and bucket angle, respectively. means, an inclination angle detection means for detecting an inclination angle in the direction in which the working machine of the vehicle upper revolving structure is facing, and a boom angle, an arm angle, and a bucket angle detected by the angle detection means and detected by the inclination angle detection means. and a control means for controlling the flow rate of pressure oil supplied to the bucket cylinder so that the bucket absolute angle calculated based on the tilt angle coincides with the bucket absolute angle instructed by the bucket absolute angle indicating means. There is.

[Operation] First, when the bucket absolute angle is specified by the bucket absolute angle indicating means, the bucket angle required to reach the specified bucket absolute angle is determined from the actual boom angle, arm angle, and inclination angle. Using the obtained bucket angle as a target value, the flow rate of pressure oil supplied to the bucket cylinder is controlled so that the bucket angle of the actual machine becomes the target bucket angle.

[Example] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 shows the boom 1 of a power shovel. This is a schematic diagram of each working machine with arm 2° and bucket 3.The rotating body at the top of the excavator body is at an angle due to the slope of the ground! The figure shows the case where the slope is slanted. That is, in the figure, if the coordinates of the plane containing each work machine, with the horizontal direction as the X-axis and the vertical direction as the Y-axis, are taken as absolute coordinates, then the vehicle body coordinates are changed from the absolute coordinates by the inclination angle 8 of the rotating body. It rotates by 8 angles.

In addition, the angle α between the vehicle body coordinate Y@ and the boom 1 is the boom angle, the angle β between the boom 1 and the arm 2 is the arm angle, the angle γ between the arm 2 and the bucket 3 is the bucket angle, and the bucket foot is The angle θ formed by the line segment between the pin C and the bucket edge point and the absolute horizontal is defined as the bucket absolute angle θ.

From Figure 2, the absolute bucket angle θ is the boom angle α.

Depending on the arm angle β, bucket angle γ, and inclination angle, the following formula, 0-3π/2-(α→-β+γ+8)...(1)
It can be expressed as

Therefore, by controlling the bucket angle γ based on the above-mentioned item (1), the bucket absolute angle θ can be always controlled to be constant regardless of the boom angle α, the arm angle β, and the inclination angle 8.

Now, if we calculate the control target angle γ of the bucket angle ef to keep the absolute bucket angle θ constant, we will get the following. That is, the target absolute bucket angle θ is θ. Then, the angles at that time are α0°β, γ, and 3o, respectively, and the respective angles at the time when the target should be controlled are θ, α, β, and γ.

g, the deviation Δθ is given by the following formula, Δθ=θ0−〇=3π/2−(αθ+β0+To−+1o)−(3π/
2-(α+β+γ10K)) (2) Here, since the bucket absolute angle θ is controlled to be constant, Δθ=0 in the above (2), and rearranging the bucket angle γ, γ−α0+β0+γo+
KO-(α+β13)...(3). If the rotation of the bucket is controlled using this bucket angle γ as the target angle ef degree γ of the bucket angle, then
It is possible to perform constant control of the bucket absolute angle.

FIG. 1 is a block diagram showing one embodiment of the present invention, and is an embodiment of a device that switches between conventional bucket control by lever operation and control to keep the absolute angle of the bucket constant according to the present invention.

In the same figure, the electric lever 10 sends a signal to the integrator 11 which indicates the bucket rotation speed ↑ref according to the amount by which the lever is tilted.
and is output to the speed command zero detection circuit 12. Note that when the electric lever 10 is released, the RCF lever returns to the neutral position and outputs a signal indicating f=O.

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

The speed command zero detection circuit 13 detects that the bucket rotation speed t is 0.
It detects whether or not f''. Signal when f=Oef! 19 to the changeover switch 13,
The movable contact piece 13c of the changeover switch 13 is connected to the contact point 13b, and the control is switched to constant bucket absolute angle control, and when T is 0, the operator is giving a command to move the bucket, so the signal '''0 is
9 is added to the changeover switch 13, the movable contact piece 13c of the changeover switch is connected to the contact 13a, and the bucket control is switched to lever operation.

The differentiator 14 takes the differentiation of the rising edge of the signal applied from the speed command zero detection circuit 12, and calculates the bucket rotation speed tl''.
A latch signal (pulse signal) is output to the latch circuit 15 at the first time when 0f becomes O.

Data input to the latch circuit 15 includes a tilt angle detector 16, a boom angle detector 17. The arm angle detector 18 and the bucket angle detector 19 each detect a tilt angle 3 as shown in FIG.
．． Boom angle α, arm angle β and bucket 1-angle γ are added. Here, the inclination angle detector 16 is configured to detect the inclination angle of the upper revolving body 4 in the direction in which the working machine is facing.
For example, a pendulum-type inclinometer can be considered.

Of course, this inclination angle detector 16 has an inclination angle (8
) is detected, but the upper revolving body 4 moves 180° from this state.
When turning, an inclination angle (-8) will be detected.

When a latch signal is applied from the differentiator 14, the latch circuit 15 receives an angle 8, α, β, γ applied from one of the detectors 16 to 16.
, and add these to the adder 20 as angles 8, α0°β, and γ0 until the latched signal is applied again. The adder 20 adds the signals applied from the latch circuit 15 and adds a signal indicating the added value (α.+β.+To+1°) to the positive input of the addition point 21.

The adder 22 is connected to the tilt angle detector 16. Signals indicating the angles 3, α, and β added from the boom angle detector 17 and the arm angle detector 18 are added, and a signal indicating the added p value (α+β 10 g) is added to the negative input of the addition point 21.

The addition point 21 adds the two human power signals and sends the summation value, that is, a signal indicating the RCF bucket angle γ (refer to equation (3)) for controlling the bucket absolute angle constant to the contact 13b of the changeover switch 13. Output.

As described above, the movable contact piece 13c of the changeover switch 13 is switched by the output of the speed command zero detection circuit 12, and the target angle γre related to bucket control by lever operation is switched.
f or target angle γra related to constant bucket absolute angle control
A signal indicating either one of t is selectively outputted to the addition point 23. A feedback amount indicating the actual bucket angle γ of the bucket 3 is added to the other input of the summing point 23 from the bucket angle detector 19.

ef At the addition point 23, the deviation between the bucket target angle γ and the actual bucket angle γ is calculated, and this deviation signal is used for proportional, integral, differential compensation, etc. to quickly cancel this deviation and perform stable control. is applied to the flow control valve 25 via a compensator 24 that performs the following.

The flow control valve 25 supplies pressure oil to the bucket cylinder 5 at a flow rate according to the input signal. As a result, the rotation of the bucket 3 is controlled to reach the target angle γref.

In this embodiment, the absolute bucket angle of the actual machine at the first point in time when the electric lever 10 is no longer operated is set as the target absolute bucket angle, and this is held constant. The means for instructing is not limited to this. For example, a setting means for directly setting the absolute bucket angle may be provided, and the set absolute bucket angle may be held constant.

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

[Effects of the Invention] As explained above, according to the present invention, the absolute bucket angle can be kept constant even if the inclination angle in the direction in which the working machine of the upper revolving structure is facing, the boom angle, and the arm angle change. can. Therefore, when turning or traveling on a slope, for example, it is possible to prevent cargo from spilling even if the operator does not operate the bucket, and the burden on the operator in operating the bucket is drastically reduced.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a diagram showing the angles of various parts of the working machine of a power shovel used to explain the invention, Fig. 3 (a) and ( b) is a schematic diagram of a power shovel used to explain the conventional problems. 1...Boom, 2...Arm, 3...Bucket,
4... Upper revolving body, 5... Bucket cylinder, 10
... Electric lever, 11 ... Integrator, 12 ... Speed command zero detection circuit, 13 ... Changeover switch, 14 ...
differentiator, 15... latch circuit, 16... tilt angle detector, 17... boom angle detector, 18... arm angle detector, 19... bucket angle detector, 20.22.・・・
Adder, 24... Compensator, 25... Flow rate control valve. Figure 2 and l: frame a: 7-arm angle 2: arm β: 7-arm angle B: arm 7-bun ρ: bracket 1. Toki Euphori Angle C: Ha゛°ke,, To7-Topishi

Claims (3)

[Claims] (1) A bucket absolute angle indicating means for indicating the bucket absolute angle in absolute coordinates, an angle detecting means for detecting the boom angle, arm angle, and bucket angle, respectively, and the direction in which the work equipment of the upper vehicle body revolving structure is facing. and a bucket absolute angle calculated based on the boom angle, arm angle, and bucket angle detected by the angle detection means and the inclination angle detected by the inclination angle detection means. A bucket angle control device for a power shovel, comprising: a control means for controlling a pressure oil supply flow rate to a bucket cylinder so as to match the bucket absolute angle instructed by the bucket absolute angle instruction means. (2) The bucket absolute angle instructing means includes a means for commanding constant bucket absolute angle control, and a means for commanding constant bucket absolute angle control, and an angle detected by the angle detecting means and the inclination angle detecting means at the time when the constant bucket absolute angle control is commanded by the command means. A bucket angle control device for a power shovel according to claim 1, comprising means for determining a target absolute bucket angle based on a boom angle, an arm angle, a bucket angle, and an inclination angle. (3) The means for commanding the constant bucket absolute angle control,
A bucket for a power shovel according to claim (2), which receives an output signal from an operating lever that commands a bucket rotation speed, and outputs a command signal when this signal becomes 0. Angle control device.