JPH0324933B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an excavation control device for a hydraulic excavator that is capable of highly accurate control.

(Prior Art) Conventionally, as a device for controlling excavation with a hydraulic excavator, for example, as disclosed in Japanese Patent Publication No. 57-28771,
There is known a device that automatically lowers the boom in accordance with arm pushing and horizontally pushes out the bucket while holding the bucket at a constant height. This device feeds back a flow rate control signal to the boom system according to the deviation between the target height of the bucket for horizontal extrusion and the current height of the bucket that changes as the arm is pushed, and uses this signal to switch the boom electrohydraulic. Feedback control is performed by switching the valve, extending and contracting the boom cylinder, and lowering the boom.
It is designed to move the bucket horizontally. In this case, in order to convert the height deviation of the bucket into the switching amount of the boom electrohydraulic switching valve corresponding to the flow rate of the boom cylinder, the control signal for the boom electrohydraulic switching valve is multiplied by a predetermined feedback gain. is being calculated.

By the way, this type of hydraulic excavator controls the joint movements of the boom, arm, and bucket, and the difference in the position of the bucket in the vertical and longitudinal directions relative to the upper revolving structure, i.e., when the bucket is in a high or low position, and the boom The amount of change in the height of the bucket with respect to the rotation angle of the arm and boom differs depending on whether the relative angle of the arm and the boom is large or small, and the response speed also differs due to the action of the moment of inertia.

However, the conventional feedback control described above simply calculates a control signal for the boom electrohydraulic switching valve by multiplying the bucket height deviation by a constant feedback gain, so the height deviation depends on the bucket position. It was difficult to control accuracy. In particular, when the operation is rapid, the initial deviation is large, and in order to control according to the large deviation, it is necessary to increase the feedback gain mentioned above.If the feedback gain is made too large, The target value is exceeded due to excessive control, and then control is performed to return the target value, and this repetition causes hunting. Also,
In the case of large hydraulic excavators, the above phenomenon is noticeable because the moment of inertia is large and there is a delay in response.

(Purpose of the Invention) The present invention has been made in order to solve such conventional problems. The present invention provides an excavation control device for a hydraulic excavator that can always accurately control the excavation control device without causing hunting and can be controlled with high precision.

(Structure of the Invention) The present invention provides for the operation of the reference work machine by using one of the boom, arm, and bucket work machines of a hydraulic excavator as a reference work machine and the other work machine as a follow-up work machine. a mechanism, a manual operating means for the operating mechanism, an operating mechanism for a follow-up work machine, and a control mechanism that sends a signal to the follow-up work machine operating mechanism to operate the follow-up work machine in accordance with the operation of the reference work machine. The control mechanism includes a detection means for measuring the current position of the bucket cart with respect to the upper revolving structure, a setting means for determining the target position of the bucket cart, and a means for providing feedback on the deviation between the current position and the target position of the bucket cart. A means for calculating the amount of feedback to the operating mechanism of the following work equipment by multiplying by a gain, and a means for calculating the amount of feedback to the operating mechanism of the following work equipment, and calculating the amount of feedback of the bucket based on the relationship between the movement amount of the reference work equipment and the movement amount of the follow-up work equipment, which vary depending on the position of the bucket. The present invention is characterized by comprising a correction means for obtaining a correction value according to the current position, and a signal generation means for outputting a signal corresponding to the operating amount of the following work machine based on the feedback amount and the correction value. be.

As a result, feedback control due to deviation is corrected according to the current position of the bucket.
We are trying to improve control performance.

(Example) First, the overall structure of a hydraulic excavator will be explained with reference to FIG. 7. In the figure, reference numeral 1 denotes a lower traveling body, and an upper rotating body 2 is rotatably provided on the upper part of the lower traveling body. The base of a boom 3 is supported by a pin 9 on the upper revolving body 2 so that it can be raised and lowered freely, the base of an arm 4 is rotatably attached to the tip of the boom 3 by a pin 10, and a bucket 5 is attached to the tip of the arm 4 by a pin 11. It is rotatably mounted. The base of the boom cylinder 6 is connected to the upper rotating structure 2 by a pin (not shown).
The rod tip is connected to the boom 3 by a pin 12. The base of the arm cylinder 7 is attached to the boom 3 with a pin (not shown), and the tip of the rod is attached to the arm 4 with a pin 13.
is connected to. The base of the bucket cylinder 8 is attached near the tip of the boom 3, and the rod tip thereof, the tip of a link 16 attached by a pin 15 near the tip of the arm 4, and the link 18 attached to the bucket 5 by a pin 17. are connected to the tip by a pin 19.

FIG. 1 is a block diagram of the control system, in which 20 is the arm operation lever, 21 is its operation amount detector, 22 is the controller, 23 is the arm operation valve, 24 is the arm directional control valve, 25 is a manual automatic changeover switch, 26 is a boom operation lever, 27 is an operation amount detector thereof, 28 is a boom operation valve, and 29 is a boom directional control valve. Each of the operation amount detectors 21 and 27 is formed of a potentiometer, for example, and is attached to each lever 20 and 26, and sends an operation signal to the controller 22 according to the amount of operation of each lever 20 and 26. The manual/automatic changeover switch 25 selects manual or automatic, and accordingly causes the controller 22 to output each of the above-mentioned operation signals as they are, or a control signal that has been subjected to arithmetic processing as described below. Each of the operating valves 23 and 28 is constituted by, for example, an electromagnetic proportional pressure reducing valve, receives a control signal (electrical signal) from the controller 22, outputs a hydraulic signal (pilot pressure) according to the input signal, and outputs a hydraulic signal (pilot pressure) according to the input signal. The spools of the directional control valves 24 and 29 are controlled by the hydraulic signal, thereby extending and contracting the arm cylinder 7 and boom cylinder 6, and rotating the arm 4 and boom 3.

30 is a boom inclination angle detector, 31 is an arm inclination angle detector, and each detector 30, 31 is composed of, for example, a potentiometer, and is attached to each pin 9, 10, and the rotation of the upper revolving structure 2 passes through the pin 9. center C ₀
The inclination angle θ ₁ of the boom 3 with respect to the upper revolving structure 2 and the inclination angle θ 2 of the arm 4 with respect to the boom ₃ are measured with respect to a vertical line C ₁ parallel to the above, and a signal corresponding to these measured values is output.

Reference numeral 32 denotes a bucket cart current position calculator, and this calculator 32 and the two tilt angle detectors 30 and 31 constitute current position detecting means for the bucket cart 5. That is, this calculator 32 calculates the inclination angle θ ₁ of the boom 3 inputted from the boom inclination detector 30 and the boom 3
Based on the length l ₁ (distance between pins 9 and 10), calculate the height h ₁ = l ₁ cosθ ₁ from pin 9 to pin 10, and calculate the absolute angle θ ₂₀ = θ ₁ of arm 4. +
Based on θ ₂ and the length l ₂ (distance between pins 10 and 11) of arm 4, calculate the height h ₂ =l ₂ cos θ ₂₀ from pin 10 to pin 11, and then calculate the above two heights. difference
The height Z=l ₁ cos θ ₁ +l ₂ cos θ ₂₀ from the pin 9 to the pin ₁₁ is calculated from the sum of h 1 and h 2 , and this height Z is set as the current position of the bucket ₅ .

33 is a target value setting device that determines the position of the bucket 5 at the start of horizontal extrusion, that is, the height Z ₀ =l ₁・
Cosθ ₁ +l ₂ ·cosθ ₂₀ is stored as the target value. The comparator 34 calculates the height deviation ΔZ= based on the target value Z ₀ input from the target value setter 33 and the current position Z input from the bucket current position calculator 32.
Calculate Z ₀ −Z. The boom angle deviation calculator 35 calculates the boom angle deviation Δθ ₁ =−ΔZ/(l ₁ cosθ ₁ ) based on the height deviation ΔZ input from the comparator 34 . The feedback amount calculator 36 multiplies the boom angle deviation Δθ ₁ inputted from the calculator 35 by a predetermined feedback gain (flow rate conversion coefficient) to calculate the feedback amount (flow rate of the boom cylinder 6) corresponding to the boom angle deviation Δθ ₁ . ) Calculate Ub ₀ .

A height corrector 37 calculates a height correction gain KZ according to the current height Z of the bucket 5 inputted from the arithmetic unit 32. This height correction gain KZ is a function of the height Z, and the relationship between the amount of displacement of the height Z and the amount of rotation of the arm 4, which varies depending on the height Z, is expressed as a ratio, and the ratio is is calculated from the above height Z as the height correction gain KZ,
For example, as shown in Figure 2, the height correction gain KZ
is kept almost constant from the lowest point Zmin of the height Z to a certain intermediate point, and gradually decreases from the intermediate point to the highest point Zmax.

38 is a arm angle corrector, and arm tilt angle detector 3
An angle correction gain Kθ ₂ corresponding to the inclination angle θ ₂ of the arm 4 input from 1 is calculated. This angle correction gain
Kθ ₂ is a function of arm inclination θ ₂ , and the relationship between the amount of rotation of arm 4 and the amount of displacement of height Z, which varies according to the inclination θ ₂ , is expressed as a ratio, and the ratio is the angle correction gain. KZ is determined from the arm inclination angle θ ₂ . For example, as shown in FIG. 3, the angle correction gain Kθ ₂ is increased as the arm inclination angle θ ₂ becomes larger. Note that the above height correction gain KZ and angle correction gain Kθ ₂ apply to boom 3 and arm 4.
It is determined by the lengths l ₁ , l ₂ , weight, and other machine parameters, and in reality it is curved, but in Figures 2 and 3, it is shown as a straight line for ease of understanding. .

Multipliers 39 and 40 multiply the feedback amount Ub ₀ calculated by the calculator 36 by the height correction gain KZ calculated by the height corrector 37 and the angle correction gain Kθ ₂ calculated by the angle corrector 38. Corrected feedback amounts Ub ₁ and Ub ₂ are calculated sequentially.

41 is a spool control signal of the boom directional control valve 29 from the above corrected feedback amount Ub ₂ .
This is a signal generator that calculates Ui. The feedback amount _Ub2 is a flow rate equivalent signal corresponding to the amount of expansion and contraction of the boom cylinder 6, and the flow rate is approximately proportional to the opening area a of the directional control valve 29, and the opening area a is determined by the spool stroke s. Therefore, first, based on the relationship (nonlinear characteristics) between the spool stroke s and the opening area a of the directional control valve 29 shown in FIG. 4a, the relationship is reversed as shown in FIG.
Then, the spool stroke s is determined from the opening area a corresponding to the feedback amount _Ub2 , and the spool control signal Ui corresponding to the spool stroke s is output. That is, the relationship between the feedback amount _Ub2 and the spool control signal Ui is an inverse function of the relationship between the spool stroke s and the opening area a of the directional control valve 29. In addition, the opening area a corresponding to the above feedback amount Ub ₂ and the spool control signal corresponding to the spool stroke s.
The relationship with Ui may be linearized as shown in FIG.

In the above configuration, when performing automatic horizontal extrusion of the bucket 5, the changeover switch 25 is set to automatic,
When the arm operating lever 20 is operated in the arm pushing direction, an operating signal M corresponding to the operating amount of the lever 20 is sent from the detector 21 to the arm operating valve 23 via the controller 22, and the operating valve 23 is operated. At the same time, a pilot pressure Pi corresponding to the operation amount M is introduced to the secondary side, the arm direction control valve 24 is switched to the arm pushing side, the arm cylinder 7 is extended, and the arm 4 is pushed out.

At this time, the Boolean inclination θ ₁ and the arm inclination θ ₂ are detected by the inclination detectors 30 and 31, and the arithmetic unit 32
The current position Z of the bucket 5 is determined by
A height deviation ΔZ is calculated by the comparator 34 based on the target value Z0 set in ₀ and the current position Z,
The boom angle deviation calculator 35 calculates the boom inclination deviation Δθ ₁ corresponding to the height deviation ΔZ,
The feedback amount calculator 36 calculates the feedback amount Ub ₀ corresponding to the flow rate of the boom cylinder 6 corresponding to the angular deviation Δθ ₁ . On the other hand, the height corrector 37 calculates a height correction gain KZ according to the height Z, and the arm angle corrector 38 calculates an angle correction gain Kθ ₂ according to the arm inclination angle θ ₂ .

Next, the multipliers 39 and 40 multiply the feedback amount Ub ₀ by the height correction gain KZ and the angle correction gain Kθ ₂ to calculate corrected feedback amounts Ub ₁ and Ub ₂ in sequence, and the signal generator 41 calculates the corrected feedback amounts Ub 1 and Ub 2 in order. The spool stroke control signal Ui of the boom directional control valve 29 is used as a signal corresponding to the operating amount of
is calculated, and this signal Ui is input to the controller 22. Then, the control signal Ui is inputted from the controller 22 to the boom operation valve 28,
The pilot pressure Up corresponding to the signal Ui is sent from the operation valve 28 to the boom directional control valve 29, and the spool of this directional control valve 29 adjusts to the above pilot pressure.
The boom is switched to the lowering direction by the stroke corresponding to Up, the boom cylinder 6 is retracted, the boom 3 is lowered by an angle corresponding to the deviation Δθ ₁ , and the bucket 5 is lowered by an amount corresponding to the deviation ΔZ.

In this way, by simply operating the arm control lever 20 in the arm pushing direction, the arm cylinder 7 is extended to push out the arm 4, and following this arm pushing, the boom cylinder 6 is retracted and the boom 3 is pushed out.
is lowered, and automatic horizontal extrusion of the bucket 5 is performed. In this case, instead of simply feeding back the feedback amount Ub ₀ based on the height deviation ΔZ of the bucket 5 and the angular deviation Δθ ₁ of the boom 3 to the boom operating valve 28, the feedback amount Ub ₀ is transferred to the height correction gain KZ. is corrected (multiplied) by the angle correction gain Kθ ₂ , converted into a spool control signal Ui by the signal generator 41, inputted to the boom operating valve 28 via the controller 22, and the boom directional control valve 28 is controlled by the operating valve 28. 2
9 to retract boom cylinder 6, and boom 3
I'm trying to lower it. For this reason, Bucket 5
Regardless of whether the control is started from a low position, when the control is started from a high position, when the control is started from a position close to the revolving superstructure, or when the control is started from a position far from the revolving superstructure, Moreover, even when the arm is operated rapidly, horizontal extrusion can be performed smoothly and with high precision without causing hunting.

In addition, if the arm control lever 20 is automatically operated in the arm pulling direction, the boom will be raised following the arm pulling with the same control as above, and the bucket 5 will be raised.
Automatic horizontal retraction is performed.

In addition, by switching the changeover switch 25 to manual mode and operating each operating lever 20, 27 (however, the bucket system is not shown), the boom 3, arm 4,
Needless to say, Bucket 5 can be operated individually.

FIG. 6 shows another embodiment, in which an arm angular velocity detector 4 is added to the control system of FIG.
2. Feedforward control using a boom angular velocity converter 43 and a feedforward amount calculator 44 is added. In FIG. 6, the same parts as in FIG. 1 are given the same reference numerals.

The arm angular velocity detector 42 receives boom inclination angle θ 1 and arm inclination angle θ ₂ which are inputted from the boom inclination angle detector 30 and the arm inclination angle detector 31 and which change every moment _.
Based on this, the rate of change of the arm absolute angle θ ₂₀ , that is, the angular velocity ωθ ₂₀ is measured. The boom angular velocity converter 42 calculates the boom angular velocity ωθ ₁ = ωθ ₂₀ based on the arm angular velocity ωθ 20, the lengths l ₁ and l ₂ of the boom 3 and the arm 4, the boom inclination θ ₁ , and the arm inclination θ _{2 .} (−l ₂
Calculate sinθ ₂₀ )/(l ₁ sinθ ₁ ). The feed forward amount calculator 43 calculates the feed forward amount Uf by multiplying the boom angle conversion speed ωθ ₁ by the feed forward gain. The adder 44 receives the feedback amount output from the multiplier 40.
The control signal U ₀ corresponding to the flow rate corresponding to the amount of expansion and contraction of the boom cylinder 6 is calculated by adding the feed forward amount Uf to Ub ₂ . Then, based on this control signal _U0 , the signal generator 41 outputs the spool control signal Ui, and the same control as above is performed thereafter, so that more accurate control is performed and the control accuracy is greatly improved. It is possible to do so.

By the way, in each of the above embodiments, the arm 4 is used as a reference work device, and the boom 3 is used as a follow-up work device, and the boom is lowered or raised in accordance with the push or pull operation of the arm 4 to automatically horizontally push out or pull in the bucket 5. However, conversely, boom 3 is used as the reference work equipment, arm 4 is used as the follow-up work equipment, and boom 3
The arm 4 may be actuated following the operation.

In addition, although the control system of the bucket 5 is not shown in the diagram, for example, when lifting a load scooped into the bucket 5 to the discharge position by simply lifting the boom, the boom 3 is used as the standard work equipment, and the bucket 5 is used for follow-up work. It is possible to easily control the load so that it does not spill by correcting the inclination angle of the bucket cart 5 with respect to the arm 4 in accordance with the lifting of the boom using a mechanism similar to that described above.

(Effects of the Invention) As described above, the present invention not only performs feedback control based on the height deviation of the bucket cart, but also corrects the feedback control according to the current position of the bucket cart. Therefore, even if the machine is operated rapidly or is a large machine, it can always be accurately controlled according to the position of the bucket, and can be controlled with high precision without hunting.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a control system showing an embodiment of the present invention, Fig. 2 is a graph showing an example of calculating the height correction gain, Fig. 3 is a graph showing an example of calculating the angle correction gain, and Fig. 4 a. , b is a graph showing an example of calculating a spool control signal based on the relationship between the spool stroke and the opening area of the directional control valve and the inverse relationship,
FIG. 5 is a graph showing another example of calculation of the spool control signal, FIG. 6 is a diagram corresponding to FIG. 1 showing another embodiment of the control system, and FIG. 7 is a side view of the hydraulic excavator. 1... Lower traveling body, 2... Upper revolving body, 3...
Boom (following work equipment), 4...Arm (standard work equipment), 5...Bucket, 6...Boom cylinder,
7... Arm cylinder, 8... Bucket cylinder, 20... Arm operation lever, 21... Arm operation amount detector, 22... Controller, 23
...Arm operation valve, 24...Arm directional control valve, 26...Boom operation lever, 27...Boom operation amount detector, 28...Boom operation valve, 2
9... Boom directional control valve, 30... Boom inclination detector, 31... Arm inclination detector, 32... Bucket current position calculator, 33... Target value setter,
34...Comparator, 35...Boom angle deviation calculator, 36...Feedback amount calculator, 37...
Height corrector, 38... Angle corrector, 39, 40...
...Multiplier, 41...Signal generator, 42...Arm angular velocity calculator, 43...Boom angular velocity calculator, 4
4...Feedback amount calculator.

Claims (1)

[Scope of Claims] 1 Among the boom, arm, and bucket work machines of a hydraulic excavator, one work machine is a reference work machine, and the other work machine is a follow-up work machine, and the operating mechanism of the reference work machine and , manual operating means for the actuation mechanism;
The control mechanism includes an operating mechanism for a following work machine, and a control mechanism that sends a signal to the operating mechanism for the follow-up work machine to operate the follow-up work machine in accordance with the operation of the reference work machine, and the control mechanism is configured to a detecting means for measuring the current position of the bucket tot with respect to the body; a setting means for determining the target position of the bucket tot; means for calculating a feedback amount; and correction means for calculating a correction value according to the current position of the bucket cart based on the relationship between the movement amount of the reference work machine and the movement amount of the follower work machine, which vary depending on the position of the bucket cart. 1. An excavation control device for a hydraulic excavator, comprising: signal generating means for outputting a signal corresponding to the operating amount of a follow-up work machine based on the feedback amount and correction value. 2. The arm is a reference work equipment and the boom is a follow-up work equipment, and the detection means measures the position of the bucket based on the inclination angle of the boom with respect to the upper revolving structure, the inclination angle of the arm with respect to the boom, and the lengths of the boom and arm. In addition, as the correction means, a height correction gain is calculated as a function of the height of the bucket based on the relationship between the amount of displacement of the height of the bucket and the amount of rotation of the arm, which varies depending on the height of the bucket. , the signal generating means uses the angle correction gain calculated as a function of the inclination angle of the arm based on the relationship between the amount of height displacement of the bucket that changes depending on the inclination angle of the arm and the amount of rotation of the arm. 2. The excavation control device for a hydraulic excavator according to claim 1, wherein the feedback amount is multiplied by a height correction gain and an angle correction gain to output a signal corresponding to a boom operation amount.