JP2826459B2 - Hydraulic excavator front vibration suppression control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration control device for a hydraulic excavator, which drives a hydraulic cylinder mounted on a boom, an arm, or a bucket by a pump, a valve, or the like.

[0002]

2. Description of the Related Art FIG. 11 shows only a boom and an arm system of a front part together with an electro-hydraulic control unit of a conventional hydraulic shovel. Although an actual hydraulic excavator is provided with a bucket indicated by a dotted line and a turning and traveling drive system, only a system related to the present invention is shown here. Also, one hydraulic pump is represented.

In FIG. 11, reference numeral 1 denotes an engine, and the amount of oil discharged from a pump 2 driven by the engine 1 is controlled by a pump swash plate 3.
Is variably controlled. The pump swash plate 3 is driven by a signal obtained by converting a command value from the control device 13 from electric to hydraulic by the electro-hydraulic converter 4.

[0004] The pressure oil discharged from the pump 2 is supplied to the boom cylinder 1 through control valves 5 and 7, respectively.
0, supplied to the arm cylinder 12. Boom cylinder 10
The arm cylinder 12 is mounted so as to rotate the boom 9, and the arm cylinder 12 is mounted so as to rotate the arm 11.

[0005] The control valve 5 is driven by a signal obtained by converting a command value from the control device 13 from electric to hydraulic by the electro-hydraulic converters 6.1 and 6.2. Similarly, the valve 7 is driven by signals converted from electricity to hydraulic pressure by the electro-hydraulic converters 8.1 and 8.2.

The control device 13 outputs the operation amounts to the pump 2 and the valves 5 and 7 as described above.
The operation lever signal of the operation lever 14 is used as the input signal. The operation lever signal is a signal obtained by converting the remote control pressure of the operation lever 14 into an electric signal, or the operation lever 14
Is used.

FIG. 12 is a block diagram showing a conventional vibration damping control device. In FIG. 12, the signal of the operation lever 14 is divided into a boom lever operation amount 20 and an arm lever operation amount 21. These manipulated variables 20 and 21 are transmitted to control valves 5 and 7 via valve command conversion functions 22 and 23.
Is set as the target value.

On the other hand, the target value of the pump swash plate 3 is set by using the pump swash plate command conversion function 24 as the sum of the boom lever operation amount 20 and the arm lever operation amount 21 described above.

FIG. 4 shows an example of the above-mentioned conversion functions 22, 23 and 24.
(a), (b) and FIG. The valve command conversion functions shown in FIGS. 4A and 4B take into account the dead zone of the opening area with respect to the valve displacement. The pump swash plate command conversion function shown in FIG. It is a function that defines the quantity.

In this conventional vibration damping control device, as shown in FIG. 12, delay functions 25, 26, and 27 are provided for the target values of the valves 5, 7 and the pump swash plate 3, respectively. , 26 and 27 are used as the operation amounts of the control valves 5 and 7 and the operation amount of the pump swash plate 3. Normally, a first-order lag function, a second-order lag function, a ramp function, or the like is used as the lag functions 25, 26, and 27.

In the conventional vibration damping control device shown in FIG. 12, the operation speed of the valves 5, 7 and the pump swash plate 3 is controlled by the delay functions 25 to 27 in the operation of extending, contracting, and stopping each hydraulic cylinder. Is slower than the lever operation speed, so that a vibration damping effect at the time of driving / stopping the hydraulic cylinder is brought about.

[0012]

However, the valves 5, 7
And the operation speed to the pump swash plate 3 is slow,
In particular, at the time of the stop operation, the hydraulic cylinders 10 and 12 do not stop immediately. That is, the hydraulic cylinders 10 and 12 do not stop even when the operation lever 14 is stopped, and there is a problem that the operability is impaired. And there is an obstacle nearby,
Even if it is desired to stop the hydraulic cylinders 10 and 12 immediately, the hydraulic cylinders 10 and 12 do not stop, and it is sufficiently possible that the front portion collides with an obstacle. In addition, there is a problem that the response of the operation of the hydraulic cylinder is delayed even in the operation of extending and contracting the hydraulic cylinders 10 and 12, thereby impairing the operability.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to improve the response of an actuator operation to an operation lever operation to improve operability.

[0014]

According to the first aspect of the present invention, there is provided a method for connecting a swash plate type variable displacement hydraulic pump driven by an engine to a plurality of hydraulic cylinders supporting a front portion of a hydraulic shovel. In a control device for a front part of a hydraulic excavator that controls a direction control valve provided by a signal from an operation lever for operating the movement of the front part, a signal of each hydraulic cylinder pressure and a pump outlet pressure is input to a filter. Signal, the frequency of each filter input signal is high in the vicinity of the oil column resonance point of the hydraulic cylinder, the gain is high, the frequency characteristic is such that the gain decreases in the low frequency range and high frequency range, and each filter output signal is A pressure filter for compensating the valve displacement and the pump swash plate is provided. A hydraulic shovel front vibration control device comprising: a calculator that adds the filter output signal to a pump swash plate command value and outputs the added value as a valve displacement and an operation amount of the pump swash plate. .

[0015] The invention described in claim 2 is based on the vibration damping control device of the front part of the hydraulic shovel described in claim 1, and the configuration different from that of claim 1 is that the front part of the hydraulic shovel is different. The pressure of the boom cylinder and the arm cylinder supporting the boom and the arm and the pressure at the pump outlet are detected by three pressure sensors, and each pressure signal is used as an input signal to a pressure filter. This is a feedback point as the valve displacement for the arm, the valve displacement for the arm and the compensation amount of the pump swash plate.

The invention described in claim 3 is based on the vibration damping control device for the front part of the hydraulic shovel described in claim 2. The signal of the pressure of the boom cylinder on the side to which the oil is supplied, the pressure of the arm cylinder on the side to which the pressure oil is supplied in the direction in which the arm extends (the direction in which the tip of the arm extends outward), and the signal of the pump outlet pressure are respectively filtered by the pressure filter This is a point that the filter output signal corresponding to each pressure fluctuation is fed back as a boom valve displacement, an arm valve displacement, and a compensation amount of the pump swash plate as an input signal, and the arithmetic unit outputs the boom raising operation signal. Only when it decreases or stops, the boom filter output signal is added to the boom valve displacement command value, and the arm extension operation signal decreases or Adding the arm filter output signal to the displacement command value of the arm valve only when stopped, the pump swash plate command values are those always adds filter output signal pump.

[0017] The invention described in claim 4 is based on the vibration control device for the front part of the hydraulic shovel described in claim 3, and the boom raising operation signal or the arm extension operation signal decreases or stops. Only in this case, the boom or arm filter displacement signal is added to the boom or arm filter displacement signal, and the pump swash plate command value is added to the pump filter output signal. A configuration different from claim 3 is that the boom operation unit and the arm operation unit set the boom or arm filter output signal to zero a predetermined time after a change in the boom raising operation signal or the arm extension operation signal becomes small. ,
Another point is that the arithmetic unit for the pump swash plate sets the filter output signal to zero a predetermined time after the change in the pump swash plate command value becomes small.

The invention described in claim 5 is based on the vibration damping control device for the front part of the hydraulic excavator described in claim 4. The sum of the boom valve displacement operation amount and the arm valve displacement operation amount is used as a pump swash plate command value, and the sum of the pump swash plate command value and the filter output signal for the pump outlet pressure is used as the pump swash plate value. It is an operation amount of the plate.

[0019]

According to the first aspect of the present invention, the pressure filter has a characteristic that the gain becomes high near the oil column resonance point (natural frequency) of the hydraulic cylinder. A damping effect near the resonance frequency can be provided. That is, the vibration component inherent to the hydraulic cylinder is suppressed, and the vibration suppression control can be performed regardless of the operation lever.

According to a second aspect of the present invention, there is provided the pressure filter according to the first aspect, wherein signals of a boom cylinder pressure, an arm cylinder pressure and a pump outlet pressure detected by three pressure sensors are respectively applied to the pressure filter. , And the filter output signals are used as the displacement of the boom valve, the displacement of the arm valve, and the compensation amount of the pump swash plate, respectively. That is, the filter output signal is added to each valve displacement command value and pump swash plate command value corresponding to the lever operation signal, and the added value is used as each valve displacement and pump swash plate operation amount.

According to the third aspect of the present invention, since a pressure filter that feeds back a value (specifically, a differential value of the pressure) according to the pressure fluctuation is used, the flow of the hydraulic cylinder at the time of the stop operation by the lever is controlled. Thus, the reaction of the hydraulic cylinder operation at the time of the operation of extending and contracting the hydraulic cylinder can be accelerated, and the operability can be improved. In general, by using this means, the operation and responsiveness of the front portion by the operation lever is not impaired, a vibration damping effect can be provided, and the operability can be improved.

According to a fourth aspect of the present invention, there is provided the pressure filter according to the third aspect, wherein the pressure of the boom cylinder on the side to which the pressurized oil is supplied in the boom raising direction, the direction in which the arm is extended (the tip of the arm extends outward). The signal of the pressure of the arm cylinder on the side to which the pressure oil is supplied in the direction in which the pressure oil is supplied and the pump outlet pressure are used as the input signals of the pressure filter, respectively, and the output signals of the respective filters are used as the boom valve displacement, the arm valve displacement and the pump, respectively. The filter output signal is added to the displacement command of the boom valve only when the boom raising operation decreases or stops, and the filter output signal is added after a predetermined time after the change in the operation becomes very small. The output signal is set to zero, and the filter output signal is added to the arm valve displacement command only when the arm extension operation decreases or stops, Further, after the change in the operation becomes small, the filter output signal is set to zero after a predetermined time, the filter output signal is added to the pump swash plate command, and after the change in the command becomes small, After a lapse of time, the filter output signal is set to zero, and the added values are used as the valve displacement and the operation amount of the pump swash plate.

According to a fifth aspect of the present invention, there is provided the pressure filter according to the third aspect, wherein the pressure of the boom cylinder on the side to which the pressurized oil is supplied in the boom raising direction and the direction in which the arm extends (the tip of the arm extends outward). The signal of the pressure of the arm cylinder on the side to which the pressure oil is supplied in the direction in which the pressure oil is supplied and the pump outlet pressure are used as the input signals of the pressure filter, respectively, and the output signals of the respective filters are used as the boom valve displacement, the arm valve displacement and the pump, respectively. The filter output signal is added to the displacement command of the boom valve only when the boom raising operation decreases or stops, and the filter output signal is added after a predetermined time after the change in the operation becomes very small. The output signal is set to zero, and the filter output signal is added to the arm valve displacement command only when the arm extension operation decreases or stops, Further, after the change of the operation becomes small, the filter output signal is set to zero after a predetermined time, the added value is set as the operation amount of each valve displacement, and the added value of the operation amount is set as a command of the pump swash plate. The value obtained by adding the pump swash plate command value and the filter output signal for the pump pressure is defined as the pump swash plate operation amount.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in FIGS. FIG. 11 and FIG.
The same parts as in the conventional example shown in FIG. 2 are denoted by the same reference numerals, and description thereof may be omitted.

(Schematic Description of the Drawings) FIG. 2 shows the electro-hydraulic control unit and the front part of the hydraulic shovel according to the present invention, and the front part shows only the boom and arm systems as in FIG. It is.

FIG. 1 is a block diagram showing a first embodiment of the vibration damping control means constructed in the control device 15 according to the present invention. FIG. 3 is a block diagram showing a second embodiment of the vibration damping control means configured in the control device 15 similar to FIG.

FIG. 4 shows the valve command conversion functions 22 and 23 in FIGS. 1 and 3, which are the same as those used in the prior art. FIG. 5 shows a pump swash plate command conversion function, which is also the same as that used in the prior art.

FIG. 6 is a block diagram of a pressure filter used in the control device 15 shown in FIGS. 1 and 3, and FIG.
This explains the frequency characteristics of the pressure filter.

FIG. 8 shows the operation flow of the operation units 31 and 33 in FIG. 1. FIG. 9 (a) shows the operation flow of FIG.
FIG. 9B shows the operation flow of the operation unit 35 'in FIG. 3, and FIG. 9B shows the operation flow of the operation unit 35' in FIG.

FIG. 10 schematically shows changes over time in the lever operation amount, hydraulic cylinder pressure, valve displacement operation amount, pump pressure and pump swash plate operation amount when the present invention is used.

(Explanation of Structure) First, the structure of FIG. 2 shows only the boom 9 and the arm 11 system similarly to FIG. 11 shown in the above-mentioned prior art, and FIG. The difference is that the pressure sensors 16, 17, 18 are added and the input signal to the control device 15 according to the present invention is different from the pressure sensor.
The control unit 15 uses a pressure filter and a filter output signal to output a valve displacement command value (hereinafter, referred to as a valve displacement target value) or a pump swash plate command, as described later. And an arithmetic unit for compensating the value (hereinafter, referred to as a pump swash plate target value).

Here, the pressure sensor 16 is provided in the discharge line of the swash plate type variable displacement hydraulic pump 2 to detect a pump outlet pressure, and the pressure sensor 17 is provided on the bottom side of the boom cylinder 10. Side pressure, and pressure sensor
Reference numeral 18 is provided on the rod side of the arm cylinder 12, and is configured to detect the pressure on the rod side.

In the embodiment shown in FIG.
An example is shown in which a hydraulic cylinder pressure in a direction in which the arm 11 is raised and a direction in which the arm 11 is extended (a direction in which the tip of the arm expands outward, an arm extension operation) is detected, and vibration suppression control is performed.

Next, FIG. 1 is a block diagram showing a first embodiment of a control device 15 according to the present invention.
The components from 20 to the swash plate command conversion function 24 are the same as those in the block diagram shown in FIG. In FIG. 1, the target valve displacement value of the valve 5 is Xt1, the target valve displacement value of the valve 7 is Xt2, and the target value of the pump swash plate 3 is φ.
t.

Target value Xt1 of valve 5 and pressure filter
The filter output signal Dp1 of 32 is input to the arithmetic unit 31, and the output of the arithmetic unit 31 becomes the valve displacement operation amount Xc1 of the valve 5. As the filter input signal to the pressure filter 32, the pressure P1 detected by the pressure sensor 17 on the bottom side of the boom cylinder 10 is used. The arithmetic unit 31 performs an operation on the input signal described above, and the operation flow is shown in FIG.

Target value Xt2 of valve 7 and pressure filter
The filter output signal Dp2 at 34 is input to the computing unit 33, and the output of the computing unit 33 is the valve displacement operation amount Xc2 of the valve 7. As the filter input signal to the pressure filter 34, the pressure P2 detected by the pressure sensor 18 on the rod side of the arm cylinder 12 is used. The arithmetic unit 33 performs an operation on the above-mentioned input signal, and the operation flow is the same as that shown in FIG. 8 (the symbols may be replaced).

The target value φt of the pump swash plate 3 and the filter output signal Dφp of the pressure filter 36 are input to an arithmetic unit 35, and the output of the arithmetic unit 35 becomes an operation amount φc of the pump swash plate 3. As a filter input signal to the pressure filter 36, the pressure Pp detected by the pressure sensor 16 on the pump outlet side is used. The operation unit 35 performs an operation on the above-mentioned input signal, and the operation flow is shown in FIG. 9 (a).

FIG. 3 is a block diagram showing a second embodiment of the control device 15 according to the present invention.
What is different from 15 is the operation amount X of control valves 5 and 7.
The difference is that the added value of c1 and Xc2 is input to the swash plate command conversion function 24 ', and the output value of the swash plate command conversion function 24' is used as the command value (target value) of the pump swash plate 3.

FIG. 6 is a block diagram of the pressure filters 32, 34 and 36. In this block diagram, S is a Laplace variable, ωL
, ΩU are filter frequencies and Kp is a filter gain. As shown in the figure, the pressure filters 32, 34 and 36 are composed of a first-order differential element and two first-order lag functions. As a matter of course, the filter frequency for each of the pressure filters 32, 34, 36 may be set individually.

FIG. 7 shows the frequency characteristics of the pressure filters 32, 34 and 36. As shown in FIG. 7, the filter frequency is adjusted so that the vicinity of the maximum value of the filter gain matches the natural frequency of the airframe (hydraulic cylinder). ωL and ωU are set.

FIG. 8 shows an arithmetic unit 31 relating to the valve 5 in FIG.
FIG. As described above, the present embodiment shows an example in which the hydraulic cylinder pressure in the direction in which the boom 9 is raised or in the direction in which the arm 11 is extended is detected, and the vibration suppression control is performed. This occurs when the operation is stopped. This is because the increasing moment of inertia is to be suddenly stopped.

In FIG. 8, the decision unit 50 is a boom cylinder.
A determiner for determining whether the extension operation of 10 is decreasing, a determiner 51 for determining a change amount of a target value of the valve 5, a calculator 52 for counting up a vibration suppression control time, The computing unit 53 is a computing unit for resetting the control time, the judging unit 54 is a judging unit for judging whether the vibration suppression control time has reached a predetermined time ΔT1, and the computing units 55 and 56 are valves 5
This is an arithmetic unit for setting the valve displacement operation amount of the above.

The calculation flow of the calculator 33 for the valve 7 is the same. In the case of the valve 7, as shown in the lower part of FIG. 8, the target value Xt1 of the valve 5 is changed to the target value Xt2 of the valve 7.
To the filter output signal Dp2 of the pressure filter 32 to the filter output signal Dp2 of the pressure filter 34, the control time ΔT1 to the control time ΔT2, the extension operation of the boom cylinder 10 to the contraction operation of the arm cylinder 12, and the symbols and names. It can be handled by changing.

FIG. 9 (a) shows a calculation flow of the calculator 35 for the pump swash plate 3 in FIG. 1, and outputs a manipulated variable φc of the pump swash plate 3. In the figure, the decision unit
Reference numeral 60 denotes a determiner for determining whether the target value φt of the pump swash plate 3 has decreased, determiner 61 a determiner for determining the amount of change of the pump swash plate target value φt, and a calculator 62 sets the vibration suppression control time. An arithmetic unit that counts up, an arithmetic unit 63 resets the control time, a determination unit 64 determines whether the vibration suppression control time has reached a predetermined time ΔT3, and an arithmetic unit 6
Reference numerals 5 and 66 denote arithmetic units for setting the operation amounts of the pump swash plate 3.

FIG. 9 (b) shows a calculation flow of the calculator 35 'for the pump swash plate 3 in FIG. 3. The determiner 60 determines whether the target value φt of the pump swash plate 3 has decreased. Calculators 65 and 66 are operation units for setting the operation amount of the pump swash plate 3.

(Explanation of Operation) Next, the operation of the embodiment shown in FIGS. 6 to 10 will be mainly described.

The pressure filters 32, 32 shown in FIGS.
34 and 36 are frequency characteristics in which the gain is highest near the natural frequency (oil column resonance point) region of the body (hydraulic cylinder), and the gain decreases in the low frequency and high frequency regions. With Such a pressure filter 32, 3
By constructing a closed loop using 4, 36, it is possible to improve the damping characteristics in the frequency range inherent to the aircraft,
The vibration characteristics of the body can be improved.

FIG. 8 shows how the filter output signal of the pressure filter 32 (or 34) is applied to the target value of the valve 5 (or 7), and FIG. 9 (a). Shows how the filter output signal of the pressure filter 36 is applied to the target value of the pump swash plate 3.

In FIG. 8, the boom cylinder 10 is an extension operation (boom raising operation), and the extension operation is reduced (reduction means that the extension operation of the hydraulic cylinder 10 is decelerated by returning the lever 14). The determination unit 50 determines whether or not the operation is stopped). In FIG. 8, "the target value Xt1 of the valve 5 decreases?" Is described, which corresponds to the above-mentioned "is the operation decreased?"

When the above judgment is true (Y), the judgment unit 51 is used. This determiner 51 determines whether or not the amount of change (decrease amount = lever return amount) of the target value Xt1 of the valve 5 is equal to or smaller than the minute value ε.

When the stop operation for raising the boom (extension of the boom cylinder) is performed by a very small operation, the front portion does not vibrate. In this case, the absolute value of the change amount of the target value Xt1 becomes equal to or less than ε, and after the vibration suppression control time is reset (the time count is set to zero) by the computing unit 53, the computing unit 55
The target value Xt1 of the valve 5 is output as it is as the operation amount Xc1 of the valve 5.

When the stop operation (lever return operation) of the boom raising (extension of the boom cylinder 10) is performed relatively large and fast, the absolute value of the variation of the target value Xt1 of the valve 5 is ε.
That is all. In this case, the arithmetic unit 52 counts up the vibration suppression control time.

When the vibration suppression control time is smaller than ΔT 1, the judgment unit 54 gives a false result (N), and the operation unit 56 calculates the operation amount Xc 1 of the valve 5 from the target value Xt 1 of the valve 5 by the filter output of the pressure filter 32. The value is obtained by subtracting the signal Dp1. That is, during the vibration suppression control time ΔT1, the pressure filter 32
The vibration damping effect of the

When the control time becomes equal to or longer than ΔT 1, the operation amount Xc 1 of the valve 5 is made equal to the target value Xt 1 of the valve 5 by the computing unit 55. That is, in this case, it means that the filter output signal is ignored.

By appropriately setting the control time ΔT1 to a value corresponding to the natural vibration of the hydraulic cylinder 10, the vibration can be damped in a shorter time than the vibration damping time by the simple delay element of the prior art.

If the decision unit 50 is false (N),
By resetting the control time at 53, the control time when the determination unit 50 and the determination unit 51 are true (Y) can appropriately set the control time.

The operation of the arithmetic unit 33 relating to the valve 7 for controlling the arm cylinder 12 is the same as the arithmetic flow shown in FIG. 8, but this arithmetic unit 33 replaces the "boom cylinder extension operation" in FIG. Change "Valve 5" to "Valve 7" to "Shrink operation", and further change Xt1 to Xt2
In addition, Dp1 is changed to Dp2, ΔT1 is changed to ΔT2, and Xc1 is changed to Xc2. Retracting the arm cylinder 12 as shown in FIG. 2 extends the arm 11 (arm
Eleven tips are spread out).

In FIG. 9 (a), when it is determined by the determiner 60 that the target value φt of the pump swash plate 3 has increased (the determination result is false), the arithmetic unit 63 resets the control time, and The operation amount φc of the pump swash plate 3 is a value obtained by subtracting the filter output signal Dφp of the pressure filter 36 from the pump swash plate target value φt by the computing unit 65.

Regarding the operation of the pump swash plate 3, when the target value φt is increasing, the value of the pressure filter 36 is always applied, but when the target value φt is decreasing, the pressure filter 36 is controlled by the control time. Applicable restrictions are set.

The target value φ of the pump swash plate 3 is determined by the decision unit 60.
Even if t is determined to decrease, the target value φt
If it is determined that the absolute value of the change amount (decrease amount) is smaller than the reference value ε, the computing unit 63 resets the control time.

When the determinator 61 determines that the absolute value of the change (decrease) of the swash plate target value φt is larger than the reference value ε (true), the calculator 62 starts counting up the control time. ,
The operation amount φc of the pump swash plate 3 by the calculator 65 is output until the control time reaches ΔT3 in the judgment device 64.
The swash plate operation amount φc is a value obtained by subtracting the filter output signal Dφp of the pressure filter 36 from the target value φt of the pump swash plate 3. That is, during the control time ΔT3, the pressure filter
The damping effect of 36 will work.

When the determining unit 64 determines that the control time is equal to or longer than .DELTA.T3, the computing unit 66 computes a value equal to the target value .phi.t as the swash plate operation amount .phi.c.

Next, since the arithmetic unit 31 is as described above,
For example, when the extension operation of the boom cylinder 10 is started, the determination of the determiner 50 in FIG. 8 becomes false, and the valve 5 is operated with the valve target value Xt1 corresponding to the lever operation by the calculator 55 via the calculator 53, Since the pump swash plate 3 determines that the pump swash plate target value φt has increased by the decision unit 60 in FIG.
The swash plate operation amount to which the pressure filter 36 is applied by the computing unit 65 via the computing unit 63 is obtained. That is, when the valve 5 is opened, the pump swash plate 3 controls the vibration of the front part.

On the other hand, when the extension operation of the boom cylinder is stopped, the judgment of the judging device 50 in FIG. 8 becomes true, and the valve 5 is operated by the pressure filter 32 until the predetermined control time ΔT1. Similarly, for the pump swash plate 3, the swash plate operation by the pressure filter 36 is performed until the predetermined control time ΔT3.

However, in this case, since the operation of the pump swash plate 3 means the supply of oil necessary for the flow rate of the valve through the valve operation, the vibration suppression of the front portion when the extension operation of the boom cylinder 10 is stopped. Is performed mainly by valve operation.

For this reason, FIG. 3 shows an embodiment in which the sum of the valve displacement operation amounts is set as the target value of the pump swash plate 3.
FIG. 9B shows a calculation flow of the calculator 35 'for the operation of the pump swash plate at this time.

FIG. 10 schematically shows the lever operation amounts, the hydraulic cylinder pressures P1 and P2, the pump pressure Pp, and the valve operation amounts Xc1 and Xc2 and the pump swash plate operation amount φc when the vibration damping control device of the present invention is used. After the damping control time reaches a predetermined time ΔT1 or ΔT3 from the time of lever return, the filter output signal is shown in the characteristic diagram of the valve operation amounts Xc1 and Xc2 and the pump swash plate operation amount φc. Not applicable is indicated by broken lines. That is, at the time of the stop operation by the operation lever 14, the vibration suppression effect by the pressure filters 32, 34, and 36 is exerted, and the constant vibration suppression control times ΔT1, ΔT
After the lapse of T3, the possibility that the filter output signal acts excessively is cut off, and the valve operation amounts Xc1 and Xc2 and the pump swash plate operation amount φc can be quickly converged to a stable state.

As described above, when the vibration damping control device of the present invention is used, the operation and response of the front portion are controlled by the operation of the pump swash plate 3 and the valves 5 and 7 in response to the operation of the front portion by various lever operations. The operability is not impaired, and a damping effect can be provided, and the operability can be improved.

[0069]

According to the first aspect of the present invention, the displacement of the valve for controlling the hydraulic cylinder is compensated by the pressure filter having the characteristic that the gain becomes high near the oil column resonance point of the hydraulic cylinder. The vibration component unique to the cylinder can be suppressed, and the vibration suppression control can be performed regardless of the operation lever.

According to the second aspect of the present invention, even in the case of an existing hydraulic shovel, vibration suppression control can be easily performed by providing three pressure sensors on the front portion. If the above-described pressure sensor is attached to an existing hydraulic shovel, the operability can be improved by performing vibration suppression control without changing the hardware configuration of the front portion of the hydraulic shovel.

According to the third aspect of the invention, the pressure of the boom cylinder on the side to which the pressure oil is supplied in the boom raising direction and the pressure of the arm cylinder on the side to which the pressure oil is supplied in the direction in which the arm is extended are set. Each signal is used as a filter input signal to the pressure filter, and the calculator calculates the displacement command value of the boom valve or arm valve only when the boom raising operation signal or arm extension operation signal decreases or stops. Since the filter output signals are added, a remarkable vibration damping effect and operability can be obtained especially when the boom raising operation and the arm extension operation are suddenly stopped. In particular, since the above-mentioned pressure filter feeds back a value corresponding to the pressure fluctuation, it is possible to suppress the flow of the hydraulic cylinder at the time of the stop operation by the lever, and to speed up the response of the cylinder operation at the time of the hydraulic cylinder expansion / contraction operation. Operability can be improved. That is, the operation / responsiveness of the front portion by the operation lever is not impaired, a vibration damping effect can be provided, and the operability can be improved.

According to the fourth aspect of the present invention, the boom operation device or the arm operation device makes a change in the boom raising operation signal or the arm extension operation signal small, and a predetermined time after the boom operation or the arm extension operation signal has become small. The filter output signal is set to zero, and the filter output signal is set to zero a predetermined time after the change in the pump swash plate command value becomes minute by the pump swash plate computing unit. In addition to using the damping effect of the filter, after a certain damping control time has elapsed, the risk of the filter output signal acting in the opposite direction can be cut off, and the valve operation amount and pump swash plate operation amount can quickly converge to a stable state. it can.

According to the fifth aspect of the present invention, the sum of the valve displacement operation amounts is used as the command value of the pump swash plate.
By appropriately operating the pump swash plate, it is possible to appropriately supply oil required for the flow rate through the valve by operating the valve.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of a vibration damping control device according to the present invention.

FIG. 2 is a schematic configuration diagram of an electric oil control unit and a front unit of the hydraulic shovel according to the present invention.

FIG. 3 is a block diagram showing a second embodiment of the vibration damping control device of the present invention.

4 (a) is a characteristic diagram showing a valve command conversion function relating to a boom lever operation amount of the present invention, and FIG. 4 (b) is a characteristic diagram illustrating a valve command conversion function relating to an arm lever operation amount.

FIG. 5 is a characteristic diagram showing a pump swash plate command conversion function according to the present invention.

FIG. 6 is a block diagram of a pressure filter according to the present invention.

FIG. 7 is a characteristic diagram illustrating frequency characteristics of the pressure filter according to the present invention.

FIG. 8 is an operation flowchart of an operation unit 31 in FIG. 1;

9 (a) is an operation flow diagram of an operation unit 35 in FIG. 1, and FIG. 9 (b)
FIG. 4 is a calculation flowchart of the calculator 35 'in FIG.

FIG. 10 is a schematic diagram showing changes over time of main data when the present invention is used.

FIG. 11 is a schematic configuration diagram of an electric oil control section and a front section of a conventional hydraulic shovel.

FIG. 12 is a block diagram showing a conventional vibration damping control device.

[Explanation of symbols]

 14 Operation lever 15 Control device 16, 17, 18 Pressure sensor 32, 34, 36 Pressure filter 31, 33, 35, 35 'Computing unit

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Makoto Samejima 2-5-1 Marunouchi, Chiyoda-ku, Tokyo Inside Mitsubishi Heavy Industries, Ltd. (56) References JP-A-5-163746 (JP, A) JP-A-64 -21201 (JP, A) JP-A-5-321297 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) E02F 9/22 F15B 11/00

Claims (5)

(57) [Claims] A directional control valve provided in a pipe from a swash plate type variable displacement hydraulic pump driven by an engine to a plurality of hydraulic cylinders supporting a front part of a hydraulic shovel, In the control device of the hydraulic excavator front part, which is controlled by a signal from an operation lever for operating the movement of the hydraulic cylinder, a signal of each hydraulic cylinder pressure and a pump outlet pressure is used as a filter input signal, and the frequency of each filter input signal is controlled by the hydraulic cylinder oil. The frequency where the gain is high near the column resonance point and the gain decreases in the low frequency region and high frequency region
Has several properties, and adds a pressure filter having a compensation amount of the filter output signals, respectively valves displacement and the pump swash plate, said filter output signal to the valve displacement command value and the pump swash plate command values for the lever operation signal And a computing unit that outputs the added value as a displacement of each valve and an operation amount of the pump swash plate. 2. A directional control hydraulic pump provided in a pipe from a swash plate type variable displacement hydraulic pump driven by an engine to a boom cylinder and an arm cylinder for supporting a front portion including a boom and an arm of a hydraulic shovel. A hydraulic excavator front section control device that controls a valve by a signal from an operation lever that operates the front section, wherein a boom cylinder pressure detected by three pressure sensors;
The signal of the arm cylinder pressure and the pump outlet pressure as filter input signals, respectively, the frequency of each filter input signal gain is reduced in the low frequency range and high frequency range higher gain in the vicinity of the oil column resonance point of the cylinders frequency
Have the characteristics, and the respective filter output signals and the pressure filter to compensate the amount of the boom valve displacement, arm valve displacement and the pump swash plate, respectively, each valve displacement command value and the pump swash plate command values for the lever operation signal A control unit for adding a filter output signal and outputting the added value as a displacement of each valve and an operation amount of a pump swash plate. 3. A directional control hydraulic pump provided in a pipe from a swash plate type variable displacement hydraulic pump driven by an engine to a boom cylinder and an arm cylinder supporting a front portion composed of a boom and an arm of a hydraulic shovel. In a control device for a hydraulic excavator front part, which controls a valve by a signal from an operation lever for operating the movement of the front part, the pressure of a boom cylinder to which pressure oil is supplied in a boom raising direction, a direction in which an arm is extended. The signals of the pressure of the arm cylinder to which the hydraulic oil is supplied and the pump outlet pressure are used as filter input signals, and the frequency of each filter input signal is high near the oil column resonance point of each cylinder. And the frequency at which the gain decreases in the high frequency range.
A pressure filter that has wave number characteristics and feeds back a filter output signal corresponding to each pressure fluctuation as a boom valve displacement, arm valve displacement, and compensation amount for the pump swash plate, and when the boom raising operation signal decreases or stops Only when the boom filter output signal is added to the boom valve displacement command value and the arm extension operation signal decreases or stops, the arm filter output signal is added to the arm valve displacement command value and the pump A control unit for constantly adding a filter output signal for the pump to the plate command value and outputting the added value as a valve displacement and an operation amount of the pump swash plate. Vibration control device. 4. A directional control hydraulic pump provided in a pipe from a swash plate type variable displacement hydraulic pump driven by an engine to a boom cylinder and an arm cylinder which supports a front portion comprising a boom and an arm of a hydraulic shovel. In a control device for a hydraulic excavator front part, which controls a valve by a signal from an operation lever for operating the movement of the front part, the pressure of a boom cylinder to which pressure oil is supplied in a boom raising direction, a direction in which an arm is extended. The signals of the pressure of the arm cylinder to which the hydraulic oil is supplied and the pump outlet pressure are used as filter input signals, and the frequency of each filter input signal is high near the oil column resonance point of each cylinder. And the frequency at which the gain decreases in the high frequency range.
A pressure filter that has wave number characteristics and feeds back a filter output signal corresponding to each pressure fluctuation as a boom valve displacement, arm valve displacement, and compensation amount for the pump swash plate, and when the boom raising operation signal decreases or stops Only the output value of the boom filter is added to the displacement command value of the boom valve, and the added value is used as an operation amount of the displacement of the boom valve. A boom calculator that sets zero to zero, and an arm filter output signal is added to the arm valve displacement command value only when the arm extension operation signal decreases or stops, and the added value is used to operate the arm valve displacement. And a filter output signal for a predetermined time after the change of the operation signal becomes very small, and the filter output signal becomes zero. The filter output signal for the pump is added to the calculator and the pump swash plate command value, and the added value is used as the operation amount of the pump swash plate, and the filter output signal becomes zero after a predetermined time from when the change in the command value becomes small. And a calculator for a pump swash plate. 5. A directional control hydraulic pump provided in a pipe from a swash plate type variable displacement hydraulic pump driven by an engine to a boom cylinder and an arm cylinder for supporting a front portion comprising a boom and an arm of a hydraulic shovel. In a control device for a hydraulic excavator front part, which controls a valve by a signal from an operation lever for operating the movement of the front part, the pressure of a boom cylinder to which pressure oil is supplied in a boom raising direction, a direction in which an arm is extended. The signals of the pressure of the arm cylinder to which the hydraulic oil is supplied and the pump outlet pressure are used as filter input signals, and the frequency of each filter input signal is high near the oil column resonance point of each cylinder. And the frequency at which the gain decreases in the high frequency range.
A pressure filter that has wave number characteristics and feeds back a filter output signal corresponding to each pressure fluctuation as a boom valve displacement, arm valve displacement, and compensation amount for the pump swash plate, and when the boom raising operation signal decreases or stops Only the output value of the boom filter is added to the displacement command value of the boom valve, and the added value is used as an operation amount of the displacement of the boom valve. A boom calculator that sets zero to zero, and an arm filter output signal is added to the arm valve displacement command value only when the arm extension operation signal decreases or stops, and the added value is used to operate the arm valve displacement. And a filter output signal for a predetermined time after the change of the operation signal becomes very small, and the filter output signal becomes zero. A calculator, an addition value of the boom valve displacement operation amount and the arm valve displacement operation amount as a command value of a pump swash plate, and a value obtained by adding the pump swash plate command value and a filter output signal with respect to a pump outlet pressure. A vibration damping control device for a hydraulic excavator front part, comprising: a calculator for a pump which is an operation amount of a pump swash plate.