JPS6154890B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic linear excavation driving device for a hydraulic excavator.

As shown in Fig. 1, a hydraulic excavator generally includes a hydraulic boom cylinder C 1 that raises and raises a boom 2 supported on a revolving structure 1, and a hydraulic cylinder C ₁ that swings an arm 3 attached to the tip of the boom 2. It is equipped with a hydraulic bucket cylinder C ₂ that tilts the bucket 4 attached to the tip of the arm ₃ , and each cylinder is operated by a lever placed on the driver's seat 5. .
Simple excavation work can be performed by sequentially operating these hydraulic cylinders, but when moving the bucket along a fixed straight line, such as when finishing a slope or horizontally excavating the bottom of a trench, it is necessary to , each hydraulic cylinder must be operated simultaneously. Conventionally, only highly skilled drivers are able to carry out such work, and in most cases they rely on manual labor, resulting in poor work efficiency.

To solve these problems, in the field of civil engineering and construction machinery such as hydraulic excavators, a model formed similar to a work equipment attachment consisting of multiple work members is used as a master device, and the output of the master device is used as a master device. A master-slave mechanism (see Japanese Patent Publication No. 47-177) has been proposed, which controls a servo system and operates a work attachment accordingly. However, the method of directly moving the master device has the disadvantage that for work equipment with a wide working range, such as a hydraulic excavator, the operator will be extremely tired if he or she moves in tandem with the work attachment. If the model's movement is reduced by increasing the similarity ratio of (If it moves by vibration)
This causes the work attachment to move, making it difficult to operate. In addition, in the conventional master-slave system, when the master-slave mechanism is not working and there is a large deviation between the displacement of the master device and the corresponding displacement of the work equipment attachment, the master-slave mechanism is activated to control the control system. If activated, the work attachment will suddenly move in a direction unintended by the driver in order to eliminate the large deviation in a short time, which is extremely dangerous.

The present invention aims to solve the above-mentioned problems of the conventional master-slave system for hydraulic excavators.The present invention is aimed at solving the above-mentioned problems of the conventional master-slave system in hydraulic excavators. In a hydraulic excavator that performs excavation work by operating a hydraulic cylinder for actuating a member, there is provided a means for setting in advance the slope φ of the excavation surface and the bucket attitude angle φ, a means for instructing the magnitude of the excavation speed, and each movable member. means for detecting the operating position of the above-mentioned means, and a calculation device that sequentially calculates the operation amount of each hydraulic cylinder for positioning the bucket position and bucket posture at which linear excavation is to be performed based on the set values, indicated values, and detected values of each of the above-mentioned means. and a means for controlling the movement of each hydraulic cylinder using the calculation results obtained from the calculation device as an input signal, detecting the positions of the arm and boom immediately before starting automatic operation, and controlling the movement of the calculation device based on the detection signal. The initial value is automatically set.

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

In the hydraulic excavator shown in Fig. 1, in order to excavate along a straight line such as
It is necessary to simultaneously control the locus of movement along a straight line such as P'Q' and control the attitude of the bucket so that the cutting edge of the bucket 4 maintains a constant angle with respect to the excavation surface. The movement locus of the arm tip is controlled by simultaneous operation of the boom cylinder C ₁ and arm cylinder C ₂ , and the attitude of the bucket 4 is controlled by the operation of the bucket cylinder C ₃ .

Now, if we choose the rotation center O of boom 2 as the origin and define the horizontal direction as the X axis and the vertical direction as the Y axis, the values of the coordinates x and y representing the position F of the arm tip will be The relative angular displacement of ∠DCE = α (angular displacement corresponding to the displacement of arm cylinder C ₂ ) and the angular displacement between boom 2 and the vehicle body ∠AOB = β (angular displacement corresponding to the displacement of boom cylinder C ₁ ) are variables. It is expressed as a function, and conversely, if the values of x and y are given, the corresponding values of α and β can be found. In other words, the arm tip F is arbitrary x,
It is possible to determine the values of α, β (and therefore the displacements of the boom cylinder C ₁ and the arm cylinder C ₂ ) required when positioning in y. Therefore, if the coordinates x and y are given along the trajectory '' that the arm tip F should pass, the momentary values of α and β required when the arm tip F moves along '' can be obtained. If these values are used as input signals and the displacement of boom cylinder C ₁ and arm cylinder C ₂ is controlled so that the values of α and β always match the input signals, the movement trajectory that the arm tip F actually passes will be ′ ′.

In addition, using the values of the input signals α and β above, the value of angular displacement ∠EFG = γ (angular displacement corresponding to the displacement of bucket cylinder C 3) required to keep the attitude angle of bucket cylinder C ₃ constant. Therefore, if the bucket cylinder _C3 is controlled using this value as an input signal, the attitude of the bucket can also be controlled.

In this way, if the movement trajectory control of the arm tip point F and the attitude control of the bucket 4 are performed simultaneously,
It is possible to automate so-called straight-line excavation work that is performed along a straight line.

Next, an operating device for performing the above control will be explained with reference to FIG.

The operation panel 6 includes dials for setting the slope of the excavation surface and the attitude angle of the bucket 4, and an operation lever for setting the excavation speed. The excavation speed is decomposed into a horizontal component and a vertical component depending on the slope of the excavation surface, and a voltage signal proportional to each speed component is sent to the calculation device 7.

The calculation device 7 integrates each velocity component to generate a voltage signal corresponding to the bucket position Fx, y, and calculates the operation amount (input signal) of each hydraulic cylinder necessary to position such a position and bucket posture. do. These input signals are sent to a servo amplifier 8, which receives a feedback signal FB obtained via a detection circuit 12 from detectors 9, 10, 11 that detect the angular displacement corresponding to the displacement of each hydraulic cylinder.
compared to Input signal IP and feedback signal
If there is an error between the FB and the FB, it is amplified by the servo amplifier 8, and its output is used to control the boom cylinder C ₁ ,
The hydraulic control valves 13, 14, and 15 that operate the arm cylinder C ₂ and the bucket cylinder C ₃ are driven in a direction that eliminates errors. In this way, the displacement of each hydraulic cylinder is controlled in accordance with the input signal IP generated from the computing device 7, and automatic excavation is performed.

The operation panel 6 and arithmetic unit 7 shown in FIG. 2 will be explained in more detail.

The operation panel 6 corresponds to the horizontal component υx and vertical component υy of the excavation speed used by the calculation device 7, the slope angle φ of the excavation surface (see Figure 1), the attitude angle φ of the bucket 4 (see Figure 1), etc. This is the part that generates the voltage signal. FIG. 5 shows the electric circuit inside the operation panel 6. The potentiometer _P1 is adapted to be linked to an operating lever 16 for giving the digging speed,
The operational amplifier OP ₁ generates a voltage e ₁ proportional to the amount of operation of the lever 16 . This voltage is the operational amplifier OP ₂
The sign is reversed at -e ₁ , and e ₁ and -e ₁ are potentiometer P. ₂ is for generating trigonometric functions. The voltage applied to the terminal is ±e ₁ , and the rotation angle of the input shaft is θ. Then, voltages corresponding to e ₁ cos θ and e ₁ sin θ appear on the two brushes. Therefore, if the dial 17 is set so that the rotation angle of the input shaft is equal to the slope angle φ of the excavation surface, the two brushes of potentiometer P ₂ will have e ₁ cos φ and
A voltage corresponding to e ₁ sinφ is generated, which becomes a horizontal component vx and a vertical component vy of the voltage corresponding to the excavation speed v.

Potentiometer P ₃ is linked with potentiometer P ₂ and dial 1 sets the slope angle φ of the excavation surface.
7, and a voltage corresponding to the angle φ is generated in the brush portion. Similarly, the potentiometer _P4 is moved by a dial 18 which sets the attitude angle φ of the bucket 4, and a voltage corresponding to the angle φ is generated in its brush portion.

The four types of voltage signals generated in this manner are sent to the arithmetic unit 7 and used to calculate input signals for the control system.

In FIG. 1, the angles and lengths of each part are determined as follows.

∠AOC=δ ₁ ∠BOX=δ ₂ ∠OCD=δ ₃ ∠ECH=δ ₄ These four angles are constant angles determined only by the dimensions of each part.

∠DCE=α ∠AOB=β EFG=γ These three angles are angular displacements corresponding to the displacements of arm cylinder C ₂ , boom cylinder C ₁ , and bucket cylinder C ₃ .

= ₁ = ₂ = ₃ Furthermore, if the angle between , , and the horizontal line is positive in the direction shown in Figure 1, then ω
Let ψ be the angle at which ₁ , ω ₂ , φ, or FG.

First, a calculation circuit for obtaining input signals α and β required for positioning the arm tip position F to a target position with coordinates x and y will be described. Using the symbols defined above, the following equation holds between x, y, α, β, etc.

x= ₁ cosω ₁ + ₂ cosω ₂ + ₃ sinω ₂ (1) y= ₁ sinω ₁ + ₂ sinω ₂ + ₃ cosω ₂ (2) ω ₁ =β−δ ₁ −δ ₂ (3) ω ₂ = (ω ₁ + π) - α - δ ₃ - δ ₄ (4) From the above equations, the steepest descent method is used to calculate the values of α and β as function values of x and y. formula
Transform (1) and (2) as follows: ε _x = ₁ cosω ₁ + ₂ cosω ₂ + ₃ sinω ₂ -x (5) ε _y = ₁ sinω ₁ + ₂ sinω ₂ - ₃ cosω ₂ -y (6) Considering a function such as P = ε _x ² + ε _y ² (7), if the values of α and β are selected so that the value of P becomes minimum, ωx and ωy become zero, that is, Equation (1) , a solution that satisfies (2) is obtained. Therefore, if we take the differential value of α, β, and P as functions of time, we get dP/dt=2[dα/dt(ε _x ∂εx/∂α+ε _y ∂
εy/∂α) +dB/dt(ε _x ∂εx/∂β+ε _y ∂εy/∂β)
](8) becomes. In order for P to be a minimum value, the condition dp/dt0 (9) must always hold. For that purpose, dα/dt=-K(ε _x ∂εx/∂α+ε _y ∂εy/∂α
)(10) dβ/dt=-K(ε _x ∂εx/∂β+ε _y ∂εy/∂β
) It suffices if the condition K>0(11) is satisfied. Here, ∂εx/∂α= ₂ cosω ₂ ― ₂ cosω ₂ (12) ∂εy/∂α=− ₂ cosω ₂ ― ₃ sinω ₂ (13) ∂εx/∂β=−ε _y −y (14) ∂ ωy/∂β=ε _x +x (15). Therefore, equations (10) and (11) become as followsdα/dt=−K[ε _x ( ₂ sinω ₂ − ₃ cosω ₂ ) −ε _y ( ₂ cosω ₂ + ₃ sinω ₂ )] (16) dB/dt=-K[-ε _x (ε _y +y)+ε _y (ε _x +x)
] (17) By combining equations (1) to (4), (16), and (17), the values of α and β corresponding to the target positions x and y can be found.

In order to move the target positions x and y at a constant gradient (angle φ), the voltages of the horizontal component υ _x and vertical component υy of the excavation speed obtained from the operation panel 6 are determined by integrating them.

The above is summarized in one arithmetic circuit as shown in Fig. 3. The integrators I ₁ and I ₂ are the parts that calculate the target position x, y of the arm tip F from each component of the excavation speed, and the integrators I ₃ and I ₄ are the parts that calculate the target position x, y of the arm tip F from each component of the excavation speed. This is the part that calculates α and β by integrating the values. The initial values of the integrators I ₃ and I ₄ are the signals α and β obtained from the detector attached to the actual hydraulic excavator, and the initial values of the integrators I ₁ and I ₂ are the initial values of α and β described above. The x and y values calculated by entering the values into equations (1) to (4) are used. The arithmetic circuit shown in FIG. 3 can obtain the values of the input signals α and β when the arm tip F is linearly moved at a speed given from the operation panel 6. In the figure, A ₁ to A ₁₀ are adders, I ₁ to I ₄ are integrators, SC ₁ to _{SC 6} are code converters, M ₁ to _{M 4} are multipliers,
FG ₁ to FG ₄ indicate trigonometric function units.

Next, we will discuss the arithmetic circuit that obtains the input signal to keep the attitude angle of the bucket constant. Controlling the attitude angle of the bucket is nothing but keeping the angle φ constant in FIG. Therefore, by finding the function between each angle using the symbols shown in the figure, the following equation holds true.

φ+ψ+γ=ω ₂ +π/2 (18) Combining this equation with equations (3) and (4) gives γ=β−α−φ−ψ+δ (19) However, δ=3/2π−δ ₁ −δ ₂ − δ ₃ - δ ₄ (constant angle) (20). Equation (19) gives the input signal of γ necessary to keep the attitude angle ψ of the bucket constant even if the angles α and β change during excavation along a plane with slope angle φ. ing. A circuit for performing the calculation of equation (19) is shown in FIG. φ and ψ are voltage signals set by dials on the operation panel, δ is a constant voltage corresponding to the angle corresponding to equation (20), and α and β are the output voltages of the arithmetic circuit in Figure 3 or obtained from each detector. Use the voltage that can be used.
In addition, in FIG. 4, 19 is a constant voltage generator, 2
0 is an adder.

Since the contents of the operation panel and the arithmetic unit have been clarified with reference to FIGS. 3 to 5, the operation of the automatic driving system according to the present invention will be explained in detail again.

The driver operates each hydraulic cylinder by normal manual operation and sets the bucket 4 at an arbitrary position (depending on the work) as the automatic operation starting point. At this time, the α and β voltage signals obtained from the detector are set as the initial conditions of the integrators I ₃ and I ₄ in FIG. 3. Next, the slope φ of the plane to be excavated and the attitude angle ψ of the bucket 4 are set using the dial 17, and when the operation lever is operated, a voltage signal corresponding to each angle and an excavation speed proportional to the lever operation amount are set horizontally and vertically. The direction component is sent to an arithmetic circuit.

The arithmetic circuit calculates the bucket position at that time from the initial conditions set in the integrator, and calculates α required to excavate at a given speed along the plane of slope φ set at that position as the starting point of excavation. , β and an input signal γ for maintaining the bucket attitude at a set angle ψ, and the servo amplifier 8
send to

On the other hand, detectors 9, 10, and 11 attached to various parts of the hydraulic excavator constantly detect the current values of α, β, and γ, and the values are sent to the servo amplifier 8 as a feedback signal. The servo amplifier 8 determines the deviation between the input signal IP and the feedback signal FB, amplifies it, and uses the amplified voltage to operate the arm cylinder, boom cylinder, and bucket cylinder using hydraulic control valves 14, 13, 15 to control α, β, and γ so that they always follow the input signal. Therefore, after setting the required value with the dial on the control panel 6, the operator only needs to specify the excavation speed using the automatic operation lever, and each hydraulic cylinder will be automatically operated, allowing straight-line excavation to be performed at the given speed. It is done.

The above is the operation in the case of automatic operation, but such a hydraulic excavator must also be able to perform excavation work by normal manual operation. Therefore, a device that performs a switching operation between automatic operation and normal manual operation using the above-mentioned operating device will be described.

FIG. 6 shows an automatic driving device including a switching mechanism between manual operation and automatic operation, and the same reference numerals as those in the previously explained figures in the figure indicate the same parts. The oil passages of the pressure oil flowing into each hydraulic cylinder C ₁ , C ₂ , C ₃ are switched by solenoid valves 21A, 21B, 21C, and in the case of manual operation, manual switching valves 22A,
22B and 22C, which are controlled by hydraulic control valves 13, 14, and 15 in the case of automatic operation. Solenoid valve 21
A, 21B, and 21C are always switched to the manual switching valves 22A, 22B, and 22C by springs, respectively, and are switched to the hydraulic control valve 1 only when current is applied.
Switched to the 3, 14, and 15 sides. Switching of the solenoid valve is performed by a switch on the operation panel 6. That is, the operation panel 6 is equipped with one more switch in addition to the circuit shown in Figure 5, and when this switch is operated at the start of automatic operation, the solenoid valve is switched in the direction in which the hydraulic control valve circuit is connected, and the other switches are switched in the direction in which the hydraulic control valve circuit is connected. In this case, a manual switching valve is connected. Therefore, the manual switching valve is normally in an operable state, and the excavator can be operated manually in exactly the same way as a general hydraulic excavator. Further, the automatic operation device operates only while the switch on the operation panel 6 is pressed.

Furthermore, calculation mode control of the calculation circuit is performed in synchronization with the switching of the hydraulic circuit as described above. That is, four integrators I ₁ of the arithmetic circuit in FIG.
~ _I4 requires converting the calculation mode between the computer state where the integral operation is actually performed and the reset state where the initial conditions are set, etc. This conversion can be done by turning on the switch on the operation panel 6, that is, starting automatic operation. It enters the computer state in synchronization with the , and is reset under normal manual operation. In addition,
In Figure 3, A ₁ to _{A 10} are adders, SC ₁ to _{SC 6}
is a sign converter, M ₁ to M ₄ are multipliers, and FG ₁ to _{FG 4} are trigonometric function units.

As described above, the manual operation function of the conventional hydraulic excavator is not impaired at all, and operation switching between automatic operation and manual operation can be easily performed with a single switch.

When performing straight-line excavation using the automatic operation device described above, as the excavation progresses, arm cylinder C ₂
Alternatively, the boom cylinder _C1 reaches the end of its stroke and is no longer able to excavate in a straight line. Which cylinder reaches the stroke end first depends on the shape of the excavated surface and cannot be determined in advance. In any case, when one of the hydraulic cylinders reaches the end of its stroke, it is no longer possible to excavate in a straight line, so it is desirable that the automatic operation device automatically stop its operation when such a state is reached. A device that performs this automatic stop will be described next.

To determine when the hydraulic cylinder has reached the end of its stroke,
This is performed using the output of the arithmetic circuit, that is, the input signals for α and β. Since the range of angular displacement that α and β can move in response to the displacement of arm cylinder C ₂ and boom cylinder C ₁ is determined, the input signals of α and β generated from the arithmetic circuit are their upper limit values. Alternatively, the stroke end of the cylinder can be determined when the lower limit value is reached. Therefore, it is sufficient to provide a circuit that compares the input signals of α and β with their respective upper and lower limit values, and when any one point exceeds the limit, it is considered that that part has reached the stroke end first. . However, if the value set in the comparison circuit is selected to be equal to the limit value, when automatically excavating from one stroke end of a hydraulic cylinder to the opposite stroke end, it is possible to Since there is a risk that the comparator circuit may operate, the limit values set for each comparator circuit are set to values that are slightly larger (by δ) than the respective upper limit values and values that are slightly smaller (by δ) than the lower limit values. Thereby, the comparator circuit operates when the input signals α and β further exceed the upper or lower limit value, that is, when the input signals for each of the arm cylinder and boom cylinder exceed the end of stroke.

When it is determined that the limit of the linear excavation range has been reached as described above, it is necessary to stop automatic excavation. This is done by cutting off the current flowing through each electromagnetic valve 21A, 21B, 21C and switching the manual switching valves 22A, 22B, 22C to the operating side as shown in Fig. 6, and then resetting the calculation mode of the calculation circuit from the computer. This is done by returning to manual operation. The switching circuit of FIG. 6 also includes the above comparison circuit, the contents of which are as shown in FIG.

4 comparators 23A, 23B, 23C, 23D
determines whether the α and β input signals obtained from the arithmetic circuit exceed their respective upper limit values or lower limit values. The outputs of these comparison circuits are output from the operation panel 6.
This is combined with the automatic operation start signal obtained from the switch PS, and a logic circuit determines whether the automatic operation state or the manual operation state is present. In the automatic operation state, the output of the logic circuit is amplified by the amplifier 24 to control the calculation mode of the calculation device 7 and at the same time operate the relay 26 for exciting the electromagnetic valve solenoid 25. 26R indicates a relay contact.

Both α and β are within the upper and lower limits, and a logical operation is performed so that when the switch PS on the operation panel 6 is turned on, the automatic operation state is set, and all other operations are set to the manual operation state. However, if the hydraulic cylinder reaches the end of its stroke and changes from automatic operation to manual operation, it will not return to automatic operation even if the switch PS on the operation panel 6 is kept in the on state. .

According to the present invention as described above, straight line excavation work such as horizontal surface excavation work at the bottom of a trench for forming slopes can be automatically performed by simply instructing the magnitude of the excavation speed using a single operating lever or the like. This eliminates the difficulty and complexity of driving, reduces driver fatigue, reduces driving time, and improves work efficiency. Additionally, since the initial values of the calculation device are set based on the positions of the hydraulic excavator's arm and boom just before the start of automatic operation, there is no risk of the arm or boom suddenly moving in an unexpected direction when automatic operation starts, ensuring safety. becomes possible.

[Brief explanation of the drawing]

Fig. 1 is a side view of the hydraulic excavator, Fig. 2 is an explanatory diagram showing the outline of the automatic operation device according to the present invention, and Fig.
The figure is a calculation circuit diagram for obtaining the input signal necessary to control the position of the arm tip in Figure 2,
Figure 4 is an arithmetic circuit diagram for obtaining the input signals necessary to control the attitude of the bucket shown in Figure 2;
The figure shows an electric circuit diagram inside the operation panel that generates the voltage signal necessary to perform the calculations in Figures 3 and 4, and Figure 6
The figure is an explanatory diagram showing a switching device used to switch the automatic driving device according to the present invention to manual operation, and FIG. 7 is an explanatory diagram showing a circuit for switching the automatic driving device according to the present invention between automatic operation and manual operation. be. 2...Boom, 3...Arm, 4...Bucket, 6...Operation panel, 7...Arithmetic unit, 8...Servo amplifier, 9-11...Detector, 12...Detection circuit, 13-15 ... Hydraulic control valve, 16 ... Operation lever, 17, 18 ... Dial, 19 ... Constant voltage generator, 20 ... Adder, 21A, 21B, 21
C...Solenoid valve, 22A, 22B, 22C...Manual switching valve, 23A, 23B, 23C, 23D...Comparator, 24...Amplifier, 25...Solenoid valve solenoid, 26...Relay, 26R...Relay contact,
C ₁ ... Boom cylinder, C ₂ ... Arm cylinder, C ₃ ... Bucket cylinder, FB ... Feedback signal, IP ... Input signal, P ₁ to _{P 4} ... Potentiometer, OP ₁ , OP ₂ ...Operation amplifier, I ₁ to _{I 4}
...Integrator, PS...Push button switch.

Claims (1)

[Claims] 1. In a hydraulic excavator that pivots a work attachment consisting of movable members sequentially and rotationally connected to a revolving body and performs excavation work by operating hydraulic cylinders for operating each movable member, the excavation surface slope φ is determined in advance. and means for setting a bucket attitude angle φ;
means for instructing the magnitude of the excavation speed; means for detecting the operating position of each movable member; and positioning at a bucket position and bucket posture at which linear excavation is to be performed based on set value indication values and detected values of each of the above-mentioned means. The system is equipped with a device that sequentially calculates the operation amount of each hydraulic cylinder, and a means for controlling the movement of each hydraulic cylinder using the calculation results obtained from this calculation device as an input signal, and detects the positions of the arm and boom immediately before starting automatic operation. , an automatic linear excavation device for a hydraulic excavator, characterized in that an initial value of the calculation device is automatically set based on the detection signal.