JPH0745740B2 - Angle of repose control device for hydraulic shovel - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a repose angle control device for a hydraulic excavator.

(Prior Art) Conventionally, in hydraulic excavators, as a means for preventing the shovel itself from falling into a hole excavated by the shovel when working on a soft place of the ground or on a mountain, for example, Japanese Patent Publication
A repose angle control device shown in Japanese Patent Laid-Open No. 58-2299 is known. However, this control device has the following problems.

(A) A total of four angle detectors, that is, a vehicle body tilt angle detector and boom, arm, and bucket angle detectors are required.
The number of detectors is large, which increases the cost.

(B) In order to detect the angle of the bucket, an angle detector will be provided at the pivotal support portion with respect to the arm tip of the bucket. Therefore, the usage environment of the bucket angle detector is bad, and the impact at the time of excavation and dumping by the bucket ,vibration,
Water resistance must be taken into consideration, a special and expensive detector is required, and the detector is prone to failure, which may result in loss of control, resulting in poor reliability.

(C) When the inclination angle of the straight line connecting the front of the traveling body and the tip of the bucket with respect to the horizontal becomes larger than the set angle of repose, the bucket tip is prevented from descending from that position. Since the bucket tip is not restricted from rising further, for example, even if the distance from the excavation limit surface that is the target of the angle of repose of the arm point is smaller than the turning radius of the bucket, the vertical tip of the bucket tip from the arm point It is possible to rotate in a scraping direction that rises toward the excavation limit surface side, and by this rotation, the excavation limit surface is further excavated to the dangerous side, and the excavation limit surface collapses due to this excavation, The hydraulic excavator may fall.

(Object of the Invention) The present invention has been made in order to solve such a problem, and aims at cost reduction by reducing the number of detectors, and it is possible to perform reliable control with few failures. Moreover, even if the bucket is rotated in the scraping direction when the target value is controlled, the excavation limit surface is not excavated to the dangerous side, and the repose angle control device for the hydraulic excavator can surely prevent the hydraulic excavator from falling. Is provided.

(Structure of the Invention) The structure of the present invention will be described with reference to the functional block diagram of FIG. 1 (including the means of the embodiment).

The present invention relates to a setting means 10 for setting a ground contact limit point O at the front of a traveling body of a hydraulic excavator, a setting means 11 for setting a repose angle φ of an excavation limit surface based on the ground contact limit point O, and a vehicle body inclination. Detection means 12 for detecting the angle α, detection means 13 for detecting the rotation angle β of the boom, detection means 14 for detecting the rotation angle γ of the arm, the setting means 10, 11 and the detection means 12, 13 , 1
Calculation means 22 for calculating the working inclination angle η of the reference straight line connecting the boom foot and the arm point based on the output signal of 4
And a calculating means 23 for calculating the limit inclination angle κ of the reference straight line when the arm point is on a target straight line parallel to the excavation limit plane at a position separated from the excavation limit plane by a distance corresponding to a bucket turning radius. A comparison means 24 for comparing the work inclination angle η with the limit inclination angle κ, and an inclination angle λ of the arm around the arm point with respect to the target straight line when the work inclination angle η becomes equal to or larger than the limit inclination angle κ. And a control means 29, 30 for preventing the arm point from moving in a direction approaching the excavation limit surface side from the target straight line according to the inclination angle λ of the arm. To do.

With this configuration, the operator only needs to set the ground contact limit point O on the front part of the traveling body and the repose angle φ of the excavation limit surface based on the ground contact limit point O according to the situation of the work site. Based on the detected values of the vehicle body tilt angle α, the boom rotation angle β, and the arm rotation angle γ, the distance from the excavation limit surface to the arm point is controlled so as not to be smaller than the bucket rotation radius. The excavation limit surface is reliably prevented from being excavated.

(Embodiment) FIG. 2 and FIG. 3 show an example of a hydraulic excavator equipped with the device of the present invention, and show respective elements of setting, detection and calculation for its control. This excavator is
A boom 3 is rotatably provided on a revolving structure 2 provided above the traveling body 1, an arm 4 is rotatably provided at a tip of the boom 3, and a bucket 5 is rotatably provided at a tip of the arm 4. The boom 3, the arm 4, and the bucket 5 are provided and are rotated by the boom cylinder 6, the arm cylinder 7, and the bucket cylinder 8.

In the above hydraulic excavator, reference points, dimensions and angles of each part are determined as follows.

O: Boundary point X: Boom foot (Center of rotation of boom 3) Y: Boom point (Center of rotation of arm 4) Z: Arm point (Center of rotation of bucket 5) V: Tip of bucket 5 W: From boom foot X The line that goes vertically to the ground 9 is the ground 9.
A: Boom foot X distance from the ground B: Boom length (between boom foot X and boom point Y) C: Arm length (between boom point Y and arm point Z) Distance) D: Bucket turning radius (rotating radius of bucket tip V about arm point Z) E: Distance from point W to ground contact limit point I: Excavation limit surface φ: Set repose angle (excavation limit with respect to horizontal plane Inclination angle of surface I α: Inclination angle of the vehicle body with respect to the horizontal plane (angle formed by the ground and the horizontal plane) β: Rotation angle of the boom 3 (angle with respect to the horizontal line) γ: Rotation angle of the arm 4 (angle with respect to the horizontal line) Of these, the height A, the boom length B, the arm length C, and the bucket turning radius D are constants determined by the model. Further, the distance E from the point W to the ground contact limit point O and the angle of repose φ are arbitrarily set by the operator according to the situation of the excavation site. On the other hand, the vehicle body inclination angle α, the boom rotation angle β, and the arm rotation angle γ are detected by the angle detector.

In FIG. 2, assuming that a straight line connecting the boom foot X and the arm point Z is a reference straight line II, and an inclination angle of the reference straight line II with respect to a horizontal line is a work inclination angle η, the work inclination angle η is the work situation and the above-mentioned set value. It changes according to the following, and is calculated as follows.

η = β + ζ …… where ζ is the angle ∠YXZ that the reference straight line II makes with the boom 4, and from XYZ, C / sinζ = G / sinε ∴ζ = sin ^-1 [(C / G) sinε]… It is calculated by.

In the above equation, ε is the angle ∠ formed by the boom 3 and the arm 4.
XYZ, using the boom rotation angle β and the arm rotation angle γ, ε = 2π−γ− (π−β) = π−γ + β. Further, G is a distance between the boom foot X and the arm point Z, and is calculated from ΔXYZ using the angle ε and the known boom length B and arm length C as follows.

From the above equations, the work inclination angle η is the known boom length B and arm length C, and the boom rotation angle β that is the detected value.
And the arm rotation angle γ can be used for the calculation.

On the other hand, in FIG. 3, a straight line drawn in parallel with the excavation limit plane I at a position spaced from the excavation limit plane I by a distance corresponding to the bucket rotation radius D is a target straight line III, and the arm point Z is a target straight line. Assuming that the inclination angle of the reference straight line II with respect to the horizontal line when on III is the limiting inclination angle κ, the limiting inclination angle κ is calculated as follows.

[kappa] = [theta]-([pi] / 2- [phi]) ... Here, [theta] is the angle formed by the straight line IV perpendicular to the target straight line III from the boom foot X and the reference straight line II, and the straight line IV and the target straight line III are described above. Let Q be the intersection point with and the intersection point of the above straight line IV with the straight line extending upward along the excavation limit surface I be θ, which is represented by the angle ∠ZXQ and calculated from ΔZXQ as follows. .

θ = cos ⁻¹ (H / G) ... In the above equation, G is calculated by the above equation. H is the length of the straight line IV (segment XQ), and is calculated from ΔZXQ, ΔXOP, and ΔXOW as H = D + Fsin (φ−δ−α).

Note that F is the distance between the boom foot X and the ground contact limit point O, and δ
Is an angle ∠XOW formed by the boom foot X and the ground centering on the ground contact limit point O, and is calculated from ΔXOW as follows.

δ = tan ^-1 (A / E) ... From the above formula, the limit inclination angle κ is the known height A, boom length B, arm length C, and the set distance E and repose angle φ. Can be calculated based on the detected values of the vehicle body inclination angle α, the boom rotation angle β, and the arm rotation angle γ.

Then, by comparing the work inclination angle η with the limit inclination angle κ, it is possible to know whether the arm point Z is in the safe area or the dangerous area.

That is, when the work inclination angle η is smaller than the limit inclination angle κ (η
It can be said that <κ) is a safe area because the arm point Z is outside the target straight line III, that is, in the area on the left side of the line III in FIG. Therefore, even if the bucket 5 is rotated in the scraping direction at that position, the bucket tip P will not move to the excavation limit surface I.
There is no danger of biting into, and the boom 3, the arm 4, and the bucket 5 can be freely actuated.

However, when the work tilt angle η is greater than or equal to the limit tilt angle κ (η ≧
κ) means that the arm point Z is located within the target straight line III, that is, on the line III or on the right side of the line III in FIG. 3, and if the bucket 5 is rotated in the scraping direction at this position, The tip P may bite into the excavation limit surface I, and thus can be said to be in a dangerous area.

In such a case, it is possible to determine whether or not the arm point Z is in the safe area based on the value of the inclination angle λ of the arm 4 with respect to the target straight line III with the arm point Z as a reference.

The inclination angle λ of the arm 4 is represented by the angle ∠QZY, and is calculated from ΔXYZ and ΔXQZ as follows.

[lambda] = [mu]-([pi] / 2- [theta]) However, the angle [mu] is the tilt angle ([Delta] YZX) of the arm 4 with respect to the reference straight line II, and is calculated from [Delta] XYZ as follows.

B / sin μ = G / sin ε ∴μ = sin ^-1 [(B / G) sin ε] ... It is determined as follows according to the value of the arm inclination angle λ.

B When λ <(π / 2): Stop retracting the arm and lowering the boom When λ> (π / 2): Stop pushing the arm and lowering the boom c When λ = (π / 2): Lower the arm By this, the arm point Z can be prevented from approaching the excavation limit surface I side from the target straight line III, the distance between the arm point Z and the excavation limit surface I can be prevented from becoming smaller than the bucket rotation radius D, and the bucket tip can be prevented. It is possible to prevent V from biting into the excavation limit surface I.

Next, the above calculation and control will be described with reference to the functional block diagram of FIG.

First, the operator determines the grounding limit point O according to the work situation at the site, and sets the distance E from the point W to the grounding limit point O to the grounding limit point setting means 10 based on the grounding limit point O. , The angle of repose φ is set in the angle of repose setting means 11. On the other hand, the vehicle body inclination angle detection means 12 detects the vehicle body inclination angle α, and the boom rotation angle detection means 13 and the arm rotation angle detection means 14 detect the boom rotation angle β and the arm rotation angle γ.
Is detected. In this case, as the vehicle body inclination angle detecting means 12, a detector such as a gyroscope or a pendulum provided on the vehicle body is used. For the boom rotation angle detection means 13 and the arm rotation angle detection means 14, detectors such as potentiometers provided at the boom foot X and the boom point Y are used. However, since the actual detection values by the rotation angle detecting means 13 and 14 are based on the vehicle body and the boom point Y,
It is corrected to a numerical value based on the horizontal line by a correction means (not shown).

Then, the setting means 10, 11 and the detection means 12, 13, 1
Output signals E, φ and α, β, γ from 4 are the controller 2
Input to 0, and via the input / output device 21, work inclination angle calculating means 2
2 and the target inclination angle calculation means 23. Here, the calculation means 22 calculates the work inclination angle η (above-expression), and the calculation means 23 calculates the target inclination angle κ (above-expression).

Next, the comparing means 24 compares the work inclination angle η with the target inclination angle κ, and the determining means 24 determines whether the work inclination angle η is smaller than the limit inclination angle K (η <κ), and η <
At the time of κ, the arm point Z is in the safe area, so that the free operation signals are sent to the boom control means 29 and the arm control means 30 via the signal generating means 28, respectively.

On the other hand, when η ≧ κ, the arm point Z is the target straight line III.
Since it is on the upper side or in the dangerous area, the arm inclination angle λ (above formula) is calculated by the next arm inclination angle calculating means 26, the value of the arm inclination angle λ is judged by the judging means 27, and based on the judgment result. Then, the control signals corresponding to the above items (a) to (c) are sent to the boom control means 29 and the arm control means 30 via the signal generation means 28. The machine can move to the safe side.

Next, a boom and arm hydraulic circuit for performing the above control will be described with reference to FIG.

In FIG. 4, when the arm lever (not shown) is operated, the variable pressure reducing valves 31a, 31b provided on the arm operation valve 31 are operated.
The secondary pressures Pa ₁ and Pa ₂ are introduced to the secondary side of the
The arm directional control valve 32 is switched to the left or right by a ₁ and Pa ₂ , the hydraulic pressure supply / discharge from the main pump 33 to the arm cylinder 7 is controlled, and the arm cylinder 7 is expanded / contracted to perform arm pushing / pulling. . When a boom lever (not shown) is operated, the secondary pressures Pb ₁ and Pb are applied to the secondary side of the variable pressure reducing valves 34a and 34b provided on the boom operation valve 34.
b ₂ is introduced, and the secondary pressures Pb ₁ and Pb ₂ switch the boom directional control valve 35 to the left or right, and the main pump
The supply and discharge of pressure oil to and from the boom cylinder 6 is controlled from 36, and the boom cylinder 6 is expanded and contracted to raise or lower the boom.

In the hydraulic circuit, the variable pressure reducing valve 31a for pushing out the arm is used.
Solenoid valves 37, 38, 39 are respectively provided in the secondary side circuit and the secondary side circuit of the arm retracting variable pressure reducing valve 31b and the secondary circuit of the boom lowering variable pressure reducing valve 34b.

Now, when the arm push-out variable pressure reducing valve 31a is operated to switch the arm directional control valve 32 to the left position by the secondary pressure Pa ₁ , the arm cylinder 7 is extended and the arm push-out valve is operated. When is turned on, the secondary pressure is not sent from the variable pressure reducing valve 31a to the directional control valve 32, the directional control valve 32 is returned to the neutral position, the arm cylinder 7 is stopped, and the arm extrusion is stopped. Also, if the solenoid valves 38, 39 are turned on during the work of retracting the arm and lowering the boom,
These operations are stopped by the same operation as above. However, raising the boom is always on the safe side, so
It is not necessary to perform the above control.

The solenoid valves 37, 38, 39 are ON / OFF controlled by a signal from the controller 20, and the controller 20 has the functions shown in FIG. 1, the vehicle body inclination angle α, the boom rotation angle β, and the arm. The rotation angle γ, the set angle of repose φ, and the set distance E are input, and ON-OFF signals for the solenoid valves 37, 38, 39 are output based on these input signals.

In this way, the secondary pressure for switching the arm directional control valve 32 and the boom directional control valve 35 is turned on and off by the solenoid valves 37, 38, 39 operated by the signal from the controller 20 to prevent malfunction. , The reliability of control is improved.

Next, the control by the controller 20 will be described with reference to the flowchart of FIG.

First, the set angle of repose φ is read in step S ₁ , and step
S ₂ In setting the distance E is read in to the ground breaking point O from the point W, the vehicle body inclination angle α is read in at Step S _3, step
The boom rotation angle β is read in S ₄ , and the arm rotation angle γ is read in step S ₅ . Then, the work inclination angle η is calculated in step S ₆ , the limit inclination angle κ is calculated in step S ₇ , and then it is determined in step S ₈ whether η <κ. If YES in step S _8, the process returns to the start.

Step When at S ₈ of NO (η ≧ κ) is arm inclination angle lambda is calculated in the next step S _9, in step S ₁₀ λ <(π /
2) It is determined whether or not. If YES in step S ₁₀ proceeds to step S _13, after the signal to turn ON the solenoid valve 38 of the arm retraction stop ie Figure 4 is output, the process proceeds to step S _14. When NO is λ = (π / 2) in step S ₁₁ whether or not is determined, if YES then the process proceeds to step S _14, step when the NO
Stop arm extrusion at S ₁₂ , that is, turn on solenoid valve 37 in FIG.
Is output, and the process proceeds to step S ₁₄ . Then, the boom-down stop That fourth view of the solenoid valve in step S ₁₄ 39
The signal is output to turns ON, the then either end or not is determined in step S _15, when the NO is returned to the start, when the YES ends the control.

(Effects of the Invention) As described above, according to the present invention, the operator only sets the ground contact limit point O on the front part of the traveling body and the repose angle φ of the excavation limit surface based on the ground contact limit point O. Based on the detected values of the vehicle body tilt angle α, boom rotation angle β, and arm rotation angle γ, the distance from the excavation limit surface to the arm point can be controlled so as not to be smaller than the bucket rotation radius. It is possible to reliably prevent the excavation limit surface from being excavated. In addition, even when working on a soft place on the ground or on a mountain, by setting two ground contact limit points and excavation limit surfaces according to the situation of the work site,
Optimal control is always performed, and it is possible to reliably prevent the shovel itself from falling into a hole excavated by the shovel, which can greatly improve work safety and improve the versatility of the device. In addition, since it is not necessary to provide a pivotal support part angle detector of the bucket, the number of detectors can be reduced as compared with the conventional device, and there are few failures, and highly reliable control can be performed.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing an embodiment of the device of the present invention, FIGS. 2 and 3 are side views showing an example of a hydraulic excavator equipped with the device of the present invention, and FIG. 4 is a boom and arm in the device of the present invention. 5 is a hydraulic circuit diagram, and FIG. 5 is a control flowchart. 1 ... traveling body, 3 ... boom, 4 ... arm, 5 ... bucket,
10 ... Ground contact limit setting means, 11 ... Repose angle setting means, 12 ... Vehicle body inclination angle setting means, 13 ... Boom rotation angle detecting means, 14 ... Arm rotation angle detecting means, 20 ... Controller, 22 ... Work inclination angle calculating means , 23 ... Target inclination angle calculation means, 24 ... Comparison means,
25 ... Arm inclination angle calculating means, 27 ... Discriminating means, 28 ... Signal generating means, 29 ... Boom control means, 30 ... Arm control means, 3
7, 38, 39 ... Solenoid valve, α ... Vehicle body tilt angle, β ... Boom rotation angle, γ ... Arm rotation angle, O ... Ground contact limit point, E ... Set distance, I ... Excavation limit surface, II ... Reference straight line, III ... the target straight line,
η: work inclination angle, κ: limit inclination angle, λ: arm inclination angle.

Claims (1)

[Claims] 1. A setting means for setting a ground contact limit point of a front part of a traveling body of a hydraulic excavator, a setting means for setting an angle of repose of an excavation limit surface with the ground contact limit point as a reference, and an inclination angle of a vehicle body are detected. A detecting means, a detecting means for detecting the rotation angle of the boom, a detecting means for detecting the rotation angle of the arm, and a reference straight line connecting the boom foot and the arm point based on the output signals of the setting means and the detecting means. And a limit tilt angle of the reference straight line when there is an arm point on a target straight line parallel to the excavation limit surface that is separated from the excavation limit surface by a distance corresponding to the bucket rotation radius. And a comparing means for comparing the work inclination angle with the limit inclination angle, and an arm for a target straight line based on the arm point when the work inclination angle is equal to or greater than the limit inclination angle. A hydraulic excavator provided with a calculating means for calculating an inclination angle and a control means for preventing the arm point from moving in a direction approaching the excavation limit surface side from the target straight line according to the inclination angle of the arm. Angle of repose controller.