JPH04189925A - Vibration restraining and control device for work device in hydraulic work machine - Google Patents

Abstract

PURPOSE:To improve operability for a hydraulic work machine by detecting a control signal for an operation means and the displacement of a hydraulic actuator, obtaining the speed of the hydraulic actuator, and transiently outputting a control signal corresponding to the case of the interruption of the control signal on the basis of the detected speed signal for the auxiliary control of a flowrate to the hydraulic actuator. CONSTITUTION:A vibration restraining and control device is constituted of pressure converters 8 and 9 for detecting the pilot pressure of the first flow control valve 4, a displacement gauge 10 for detecting the displacement of a boom cylinder 2, a control unit 7 for receiving signals from the pressure converters 8 and 9, and the displacement gauge 10, and the second flow control valve 11 driven with a control signal from the control unit 7. The control unit 7 stores the operation speed of the boom cylinder 2 detected with the displacement gauge 10 before control signals from the pressure converters 8 and 9 stop the boom cylinder 2. In this state, a flow instruction value for pressure oil for supply to the boom cylinder 2 is determined via selection among transient response pattern groups of pressure oil flowrates to the cylinder 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vibration suppression control device for suppressing vibrations when a working device such as a boom is stopped in a hydraulic working machine such as a hydraulic excavator or a crane.

[Conventional technology]

In conventional hydraulic working machines, such as hydraulic excavators,
As shown in FIG. 9, a flow rate command generated by operating the operating lever 3 is input to the flow control valve 4 as a pilot pressure signal, and the operation of the flow control valve 4 causes the hydraulic pump 1 to be sent to the bottom side of the boom cylinder 2 or to the rod. The structure is such that the operating speed of the boom is controlled by controlling the flow rate of pressure oil supplied to the side.

[Problem to be solved by the invention]

In such hydraulic working machines, when the control lever 3 is returned to neutral to suddenly stop the boom, even after the pilot pressure signal instructs the stop and the flow control valve returns to neutral, the boom suddenly stops due to inertia. does not stop, and the pressure oil acts as a spring in the hydraulic circuit after the flow control valve 4, causing vibrations.

This vibration is transmitted to the vehicle body and causes the vehicle body to shake due to the effects of rattling of the vehicle body, resulting in vibration of the entire vehicle body and front. Furthermore, since this vibration has a large inertia, it is difficult to attenuate, and the vibration does not subside forever. As a result, even when a delicate operation is required, such as positioning the tip with respect to a packet, the tip continues to vibrate and positioning cannot be performed.

An object of the present invention is to suppress vibrations of a working device in a hydraulic working machine by performing auxiliary flow control to a hydraulic actuator according to the operating speed of the working device during a sudden stop operation. An object of the present invention is to provide a vibration suppression control device.

[Means to solve the problem]

In order to achieve this object, the vibration suppression control device for a working device in a hydraulic working machine according to the present invention includes a first detection means for detecting an operation signal of a flow control valve, and a second detection means for detecting a displacement of a hydraulic actuator. and the displacement of the hydraulic actuator detected by the second detection means, determine the speed of the hydraulic actuator when it is in a steady state before the operation signal detected by the first detection means instructs to stop. a first means for determining a flow rate command value of pressure oil to the hydraulic actuator based on this speed, and transiently outputting a corresponding control signal when the operation code instructs to stop; and second means for performing auxiliary flow control to the hydraulic actuator based on a control signal output from the means.

Preferably, the first means determines the flow rate command value so as to apply a damper action to the hydraulic actuator during the process in which the hydraulic actuator further moves due to inertia of the working device after the operation signal instructs to stop.

Further, the first means determines whether the operation signal is in a steady state based on whether the differential value of the operation signal is less than or equal to a preset value.

Further, the first means determines whether or not the operation signal instructs to stop, based on whether or not the value of the operation signal is equal to or less than a preset value.

Furthermore, the first means selects one of a preset group of patterns of excessive response of the flow rate of pressure oil to the hydraulic actuator based on the speed of the hydraulic actuator,
A flow rate command value is determined from this selected pattern.

[Effect]

The first means determines the speed of the hydraulic actuator in a steady state before the operation signal instructs to stop, determines the flow rate command value of pressure oil to the hydraulic actuator based on this speed, and the operation signal instructs to stop. By transiently outputting a corresponding control signal when the operation signal is stopped, and by using the control signal to perform auxiliary flow control to the hydraulic actuator using the second means, the operation of the working device is stopped after the operation signal instructs to stop. As the hydraulic actuator moves further due to inertia, a damper action is applied to the hydraulic actuator according to the actuator speed when the operation signal is in a steady state, suppressing vibrations when the working device suddenly stops.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 8, taking a hydraulic excavator as an example of a hydraulic working machine.

In FIG. 1, the hydraulic drive circuit according to the present embodiment includes a hydraulic pump 1 and a hydraulic actuator, that is, a boom, which is driven by pressure oil discharged from the hydraulic pump 1 and drives a working device, for example, a boom 2A of a hydraulic excavator. A first flow rate control that is connected between the cylinder 2, the hydraulic pump 1, and the hydraulic actuator 2, and is controlled by a pilot pressure signal generated by operating the operating lever 3 to control the flow rate of pressure oil supplied to the hydraulic actuator 2. It includes a valve 4 and a relief valve 5 that opens when the pressure between the pump 1 and the first flow control valve 4 exceeds a set value.

The vibration suppression control device of this embodiment is provided in the above hydraulic drive circuit, and the first vibration control device is operated by the operating lever 3.
The pilot pressure Pp8 of the flow control valve 4. Pp9 (hereinafter,
a pressure transducer 8 for detecting (both collectively referred to as pp);
9, a displacement meter 10 that detects the displacement of the boom cylinder 2, that is, the position of the piston, and a control unit 7 that inputs detection signals from the pressure transducer 8.9 and the displacement meter 10.
and a second flow control valve 11 that is connected between the hydraulic pump 1 and the boom cylinder 2 like the first flow control valve 4 and is driven by a control signal output from the control unit 7. .

The control unit 7 is composed of a microcomputer, and as shown in FIG. D ml converter 7
a, a central processing unit (CPU) 7b, and a read-only memory (ROM) 7C that stores control procedure programs.
, a random access memory (RAM) 7d for temporarily storing numerical values during calculation, a D/A converter 7e for output, and an amplifier 7f connected to the flow rate control valve 11 described above.
, 7g.

The control unit 7 calculates the differential value of the displacement of the boom cylinder 2 detected by the displacement meter 10 in a steady state in which the operation signal of the pilot pressure Pp output from the pressure transducers 8 and 9 does not instruct the stop of the boom cylinder 2. is stored in the RAM 17h as the operating speed of the boom cylinder 2 at that time, and when the operation signal, that is, the pilot pressure pp or stop command is issued, the transient response of the flow rate of pressure oil to the boom cylinder 2, which is set in advance, is The flow rate command value of pressure oil to the boom cylinder 2 is determined by selecting one pattern from the group of patterns that corresponds to the above-mentioned stored speed, and the corresponding control signal is transiently sent to the second flow rate control valve 11. Output.

The second flow control valve 11 is driven by a control signal from the control unit 7 to perform auxiliary flow control of the pressure oil to the boom cylinder 2 when the boom 2A is stopped, thereby suppressing vibrations of the boom cylinder 2.

Hereinafter, according to the flowchart of the control procedure program stored in the ROM 7c shown in FIGS. 3 and 4,
The operation of this embodiment will be explained in detail.

First, in step 100, the outputs of the pressure transducers 8 and 9 and the output of the displacement meter 10 are input via the A/D converter, and the pilot pressure Pp and the displacement S of the boom cylinder 2 are
is stored in RAM7d.

Next, in step 110, the current displacement Sn of the boom cylinder 2 and the displacement S of the boom cylinder 2 one sample time ago are calculated.
The speed Vt of the boom cylinder 2 is calculated by dividing the difference from n-1 by the sample time Δt.

Next, in step 120, the differential value Pp' of the operation signal is calculated by dividing the difference between the current operation signal Ppn and the operation signal Ppn-] one sample time ago by the sample time Δt.
Calculate.

Next, in step 130, the differential value Pp' of the operation signal Pp is
determines whether or not satisfies the steady state condition that instructs the boom cylinder 2 to operate at a constant speed, that is, lPp'l≦IPpo'1. If so, the process proceeds to step 140, and the boom cylinder 2 Speed in constant speed operation ■, -
is set to Vs, and if it is not satisfied, the process proceeds to step 150. In step 150, the cylinder speed V5- set in step 140 meets the non-stop condition, that is, Vs->
It is determined whether V o (-0) is satisfied, and if it is, the process proceeds to step 160; if it is not, the process returns to the beginning.

Next, in step 160, it is determined whether the operation signal Pp satisfies the condition of the stopped state, that is, JPp1≦1Ppol ("=0), and if it is satisfied, the process proceeds to step 170, and vibration suppression is performed. Start the control, and if it is not satisfied, return to the beginning.

In step 170, as shown in FIG.
The corresponding one is selected based on the speed V, (=Vs) of the boom cylinder 2 in the steady state set in .

FIG. 5 shows an example of pattern selection. For each pattern group, the flow rate Δq of pressure oil to the boom cylinder 2 is set as a function Δq=f+(t) of the control time t and pattern number 1, and one of them is selected by the pattern number i. . The pattern number i is a function in which the numerical value of the pattern number increases by one as the cylinder speed V, (=Vs) increases by a certain value.
g (Vs-) and the speed in constant speed operation of boom cylinder 2 set in step 140 ■5
The corresponding pattern number is determined from ~.

Details of the function Δq=f+(t) are shown in FIG.

The control time t is expressed by the product t=kXΔt of the sampling time Δt and the number of control cycles, and the function Δq=f1 (
t) is set such that the flow rate q rapidly increases from zero to the maximum as the number of cycles increases, and then decreases to zero again, and the total flow rate increases as the pattern number i increases.

Note that the flow rate Δq obtained from the above function Δq=L(t) is for providing a damper action to the boom cylinder 2 when the boom 2A suddenly stops, as will be described later. The flow rate differs between the sudden stop in the boom raising operation and the sudden stop in the boom lowering operation because there is a difference in inertial load. Therefore, two types of patterns are prepared, one for the boom raising operation and one for the boom lowering operation, and the pilot pressure Pp is a signal Pp9 corresponding to the boom raising operation.
or the signal Pp8 corresponding to the boom lowering operation, select one of the pattern groups, and perform the above step 1 from this pattern group.
71, pattern selection is performed.

Returning to FIG. 4, in step 172, the number of cycles k is set to =
Set to o. Next, in step 173, the flow rate Δq corresponding to the control time t=kXΔt is determined based on the selected pattern, and a corresponding control signal is output to the second flow rate control valve 11 using this as the flow rate command value.

Next, in step 174, it is determined whether or not the output of the control signal has been completed, that is, whether k≧k max is satisfied. move on. In step 175,
After setting = to +1 to proceed to the next step, the process returns to step 173.

The above steps 173 to 175 are repeated until k = kmal, and during that time, the flow control valve 11 receives step 17.
3, a control signal corresponding to the flow rate Δq is output, and k≧k
When it reaches max, the judgment in step 174 is satisfied and the process returns to the beginning. After this, since the pilot pressure Pp indicates a stopped state, lPp'l≦1Ppo'l is satisfied in step 130, and the speed of the boom cylinder 2 Vs-
is set to Vs, but at this time the boom 2A is stopped and Vs=Q is calculated in step 110, so step 1
50 is denied, and the process of returning to the beginning is repeated.

Therefore, by outputting a control signal to the flow rate control valve 11 during the control time kmax Vibration is suppressed. This will be explained in more detail below with reference to FIGS. 7 and 8.

FIG. 7 shows the relationship between the pilot pressure Pp1, which is an operation signal when suddenly stopping a boom related to a conventional hydraulic drive circuit not equipped with a vibration suppression control device, the speed Vs of the boom cylinder 2, and the displacement S of the boom cylinder 2. , boom 2A
The direction of movement is considered to be downward. At time t, the boom is lowered at a constant speed.
1. When the operation lever 3 is returned to neutral in order to suddenly stop the boom 2A, as shown in FIG. 7(a),
Pilot pressure Pp (Pp
8) starts to decrease from time tl, and is reduced to almost the tank pressure at time t2. Correspondingly, the flow rate control valve 4 also starts decreasing its opening degree from time t1, and returns to neutral at time t2.

Meanwhile, the speed of the boom cylinder 2, which had been operating in the downward direction at a constant speed, also decreases, but the boom 2A does not suddenly stop due to inertia, so as shown in FIG. 7(b), the speed of the boom cylinder 2 decreases. Even at t2, the speed does not become zero, and at time t2
At time t3, when the speed exceeds t3, the speed becomes zero, and correspondingly, as shown in FIG. 7(c), the displacement S of the boom cylinder 2 becomes minimum at time t3. After that, the pressure oil acts as a spring in the hydraulic circuit after the flow control valve 4, pushing the boom cylinder 2 back upwards, and the displacement S also increases.This process is repeated, causing vibrations. is applied to the vehicle body, causing vibration of the vehicle body due to the influence of rattling of the vehicle body, resulting in vibration of the entire vehicle body-front.

On the other hand, in this embodiment, time t1 in FIG. 8(a)
When the pilot pressure P p (P p8) starts to decrease at , the pilot pressure p
Since the differential value Pp' of p becomes lp p'l>IP po'l, the above-mentioned step 130 is no longer satisfied, and the step 140 in the steady state where the pilot pressure Pp one cycle before instructs constant speed operation. Cylinder speed V s-(=
When the memory of V s ) is maintained and P9≦Ppo near time t2, the above-mentioned step 160 is satisfied,
Vibration suppression control in step 170 is started. In this vibration suppression control, the cylinder speed V maintained in the above steady state is
Determine the pattern number i from s- in step 171 described above, select the corresponding flow rate pattern, and proceed to step 17.
In steps 2 to 175, a flow rate command value Δq is determined based on this pattern, and a corresponding control signal is output to the flow rate control valve 11.

The flow rate control valve 11 receives this signal and is driven to a predetermined opening degree, and as shown in FIG. 8(c), a flow rate corresponding to the flow rate command value Δq is supplied from the hydraulic pump 1 to the rod side of the boom cylinder 2. Moreover, the pressure oil on the bottom side is discharged to the tank 12.

As a result, as shown in FIG. 8(d), a damper action is applied to the boom cylinder 2 which continues to descend even after time t2, suppressing the occurrence of vibrations due to the compressibility of the pressure oil, and as shown in FIG. 8(e). The boom cylinder 2 stops at time t4 as shown in FIG.

As described above, according to this embodiment, the operating speed of the boom cylinder 2 in a steady state where the pilot pressure pp is kept at a constant value and instructs constant speed operation is determined, and the boom cylinder 2 is set in advance based on this speed. Select one of the patterns of transient response of the flow rate of pressure oil to cylinder 2, determine the flow rate command value Δq from the selected pattern, and send the corresponding control signal when the pilot pressure Pp instructs to stop. By temporarily controlling the flow rate of pressure oil to the boom cylinder 2, a damper effect is applied to the boom cylinder 2, so that the kinetic energy of the boom cylinder 2 can be effectively absorbed with a short delay time. , it is possible to suppress vibrations of the working equipment due to sudden changes in flow rate. Therefore, when a delicate operation is required, such as positioning the leading end of a packet, reliable positioning is possible, and the operability is significantly improved. Furthermore, since there is no feedback loop within the control loop, stable vibration suppression control can be performed with little risk of runaway.

〔Effect of the invention〕

According to the present invention, vibrations when stopping a working device suddenly are suppressed, so when delicate operations such as positioning the working device are required, reliable positioning is possible, and operability is significantly improved. There is.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a boom vibration suppression control device for a hydraulic working machine according to an embodiment of the present invention together with its hydraulic drive circuit, and FIG. 2 is a diagram showing the configuration of the control unit. 3 is a flowchart of the control procedure program stored in the ROM, FIG. 4 is a flowchart showing details of the vibration suppression control procedure of the flowchart shown in FIG. 3, and FIG. 5 shows a specific example of pattern selection. FIG. 6 is a diagram showing an example of a pattern, and FIGS. 7(a) to (c) show the relationship between the operation signal, boom cylinder speed, and boom cylinder displacement in a conventional hydraulic working machine. FIG. 8(a) is a time chart shown in FIG.
~(e) are time charts showing the relationship among the operation signal, the differential value of the operation signal, the flow rate command value, the speed of the boom cylinder, and the displacement of the boom cylinder according to the above embodiment. It is a figure shown together with the hydraulic drive circuit. Explanation of symbols 1...Hydraulic pump 2...Boom cylinder 2A...Boom (working device) 3...Operation lever (operation means) 7...Control unit (first means) 8.9. ...Pressure transducer (first detection means) 10...
Displacement meter (second detection means) 11...Flow rate control valve (second means) Fig. 1 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9

Claims (5)

[Claims] (1) A hydraulic pump, a hydraulic actuator that is driven by pressure oil discharged from the hydraulic pump and drives a working device, and a hydraulic actuator that is connected between the hydraulic pump and the hydraulic actuator and that operates according to an operation signal from an operating means. A vibration suppression control device for a working device in a hydraulic working machine having a hydraulic drive circuit including a flow rate control valve that controls the flow rate of pressure oil supplied to the first detecting means for detecting the operation signal; a second detection means for detecting a displacement of the hydraulic actuator; and from the displacement of the hydraulic actuator detected by the second detection means, the operation signal detected by the first detection means indicates a steady state before the stop command is issued. determining the speed of the hydraulic actuator in the state, determining a flow rate command value of pressure oil to the hydraulic actuator based on this speed,
a first means for transiently outputting a corresponding control signal when the operation signal instructs stop; and auxiliary flow control to the hydraulic actuator based on the control signal output from the first means. A vibration suppression control device for a working device in a hydraulic working machine, characterized in that it is provided with a second means. (2) In the vibration suppression control device for a working device in a hydraulic working machine according to claim 1, the first means further moves the hydraulic actuator due to inertia of the working device after the operation signal instructs to stop. A vibration suppression control device for a working device in a hydraulic working machine, characterized in that, in the process, the flow rate command value is determined so as to give a damper action to a hydraulic actuator. (3) In the vibration suppression control device for a working device in a hydraulic working machine according to claim 1, the first means determines whether or not the operating signal is in a steady state by setting a differential value of the operating signal in advance. A vibration suppression control device for a working device in a hydraulic working machine, characterized in that the vibration suppression control device makes a determination based on whether or not the vibration is less than or equal to a certain value. (4) In the vibration suppression control device for a working device in a hydraulic working machine according to claim 1, the first means determines whether or not the operation signal instructs to stop, the value of the operation signal being set in advance. A vibration suppression control device for a working device in a hydraulic working machine, characterized in that a vibration suppression control device for a working device in a hydraulic working machine makes a determination based on whether or not the vibration is equal to or less than a value. (5) In the vibration suppression control device for a working device in a hydraulic working machine according to claim 1, the first means controls a preset flow rate of pressure oil to the hydraulic actuator based on the speed of the hydraulic actuator. 1. A vibration suppression control device for a working device in a hydraulic working machine, characterized in that one of a group of transient response patterns is selected, and a flow rate command value is determined from the selected pattern.