JP3443018B2 - Boom device for fluid transport - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boom device for fluid transportation, and more particularly to vibration prevention thereof.

[0002]

2. Description of the Related Art FIG. 9 shows a concrete pump vehicle equipped with a boom device. The vehicle body 2 is provided with a pump (not shown) for sending out concrete which is a fluid. A boom 4 is rotatably fixed to the car body 2. The boom 4 includes a first boom 6, a second boom 8 and a third boom 10 which can be rotated by the joint portions 12, 14, 16. Pipe 24 along each boom 6, 8, 10
Is provided, the root of which is connected to the delivery pump, and the tip end is the discharge port 26.

Cylinder 1 of each joint 12, 14, 16
By controlling the expansion and contraction of 8, 20, and 22, the ejection port 26 can be set at a desired position. After that, if the delivery pump is operated, the concrete can be discharged from the discharge port 26. That is, the work of placing concrete can be performed over a wide range.

By the way, as the delivery pump, a piston type pump or a squeeze type pump is used. The piston-type delivery pump delivers fluid by two reciprocating pistons. The squeeze-type delivery pump delivers a fluid by a roller that rotates while crushing a rubber tube. In either method, fluid pulsation occurs,
This pulsation could cause the boom to vibrate significantly. When the boom vibrates greatly in this way, the discharge port 26
Might move and the fluid could not be ejected to a desired position. In addition, the vibration may increase the fatigue of the boom device and shorten its life. In order to suppress such vibrations, devices such as those disclosed in JP-A-5-141086 and JP-A-5-230999 have been proposed. Both devices detect the pulsation of the boom and control the hydraulic pressure of the drive piston of the boom so that vibration in a phase opposite to the pulsation (that is, with a phase difference of 180 degrees) is generated. This suppresses vibration.

[0005]

However, the conventional device as described above has the following problems.

FIG. 10 shows changes in gain of vibration amplitude at the tip (vibration amplitude of tip / applied vibration amplitude) and phase when vibration is applied to the boom while changing frequency.
Shown in. When the frequency is gradually increased, it resonates at the frequency fa (first resonance mode). The vibration mode at this time is as shown in FIG. 11A. The boom is treated as a cantilever beam fixed to the vehicle body 2 here. Similarly, it resonates at the frequency fb (secondary resonance mode), resulting in a vibration form as shown in FIG. 11B. Furthermore, it resonates at the frequency fc (third-order resonance mode), resulting in a vibration form as shown in FIG.

As is apparent from FIG. 10, the phase abruptly changes by 180 degrees at each resonance frequency fa, fb, fc and the anti-resonance point therebetween. Therefore, it is extremely difficult for the conventional device as described above to perform the vibration suppression control near the resonance point or the anti-resonance point. Because
Since the phase changes 180 degrees even if the frequency changes slightly, if the feedback control response is delayed,
This is because there is a risk of increasing vibration. That is,
The conventional device has a problem that it is difficult to surely suppress the vibration.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and provide a boom device for fluid transportation in which vibration of the boom is suppressed.

[0009]

A boom device for fluid transportation according to claims 1 and 2 is characterized by pulsation of fluid flowing through the transportation path.
With respect to the vibration of the boom, at least the following (1)
Use either the spring action or the damper action shown in (2) below.
Control means for controlling the driving force of the driving means so that
(1) Flow through the transport route
The resonant frequency generated by the pulsation of the fluid
Spring action to shift from pulsating frequency of flowing fluid, (2) before
With resonance frequency generated by pulsation of fluid flowing in the transportation route
Damper action that reduces the gain in the vicinity.

In the fluid transportation boom device according to a third aspect of the present invention, the control means directly or indirectly detects at least one of rotational displacement, rotational speed or rotational acceleration of the joint portion. Means, a driving force detecting means for detecting the driving force of the driving means, a calculating means for calculating a target driving force on the basis of the fluctuation detected by the fluctuation detecting means, and a driving force detecting means for detecting the target driving force. It is characterized in that a driving force adjusting means for adjusting the driving force supply to the driving means is provided so that the driving force matches the target driving force given as the driving command.

[0011]

[Action] boom device for fluid transport of claims 1 and 2, the transport
The vibration of the boom due to the pulsation of the fluid flowing in the path is
Spring action that shifts the vibration frequency from the pulsating frequency of the fluid or
Creates a damper action that reduces the gain near the resonance frequency.
As described above, the control means for controlling the driving force of the driving means is provided. The damper action can increase the damping rate of the boom vibration and suppress the vibration. In addition, the vibration of the boom is suppressed by changing the resonance frequency of the boom by the spring action and shifting the resonance frequency of the boom from the pulsation frequency of the fluid.
You can

According to another aspect of the fluid transportation boom device of the present invention, the control means directly or indirectly detects at least one of rotational displacement, rotational speed or rotational acceleration of the joint portion. Means, a driving force detecting means for detecting the driving force of the driving means, a calculating means for calculating a target driving force on the basis of the fluctuation detected by the fluctuation detecting means, and a driving force detecting means for detecting the target driving force. It is characterized in that a driving force adjusting means for adjusting the driving force supply to the driving means is provided so that the driving force matches the target driving force given as the driving command. Therefore, the spring action and the damper action can be provided by adjusting the pressure supply to the cylinder.

[0013]

FIG. 2 shows a concrete pump truck to which a fluid transport boom device according to an embodiment of the present invention is applied.
The vehicle body 2 is provided with a squeeze pump (not shown) that is a delivery unit that delivers concrete that is a fluid. The boom 4 is rotatably fixed to the car body 2 by a base joint 12. That is, drive point 3
It is possible to rotate in the vertical direction α around 2 and
The base 30 is mounted so as to be rotatable also in the horizontal direction β. It should be noted that it is the cylinder 18 that is the drive means that drives the boom 4 up and down.

The boom 4 is provided with a first boom 6, a second boom 8 and a third boom 10, and the intermediate joint 1
It is rotatably connected by 4 and 16. A pipe 24 is provided along each of the booms 6, 8 and 10, the root of which is connected to a squeeze pump, and the tip of the pipe 24 is a discharge port 2.
It is 6.

Cylinder 1 of each joint 12, 14, 16
By controlling the expansion and contraction of 8, 20, and 22, the boom 4
It is possible to set the discharge port 26 at a desired position by changing the posture of the above. Then, by operating the squeeze pump, the concrete can be discharged from the discharge port 26. That is, the work of placing concrete can be performed over a wide range.

FIG. 1 shows a part of the control means of the boom unit for fluid transportation. In this embodiment, the base joint 12
In addition, a spring action for applying a force proportional to the displacement and a damper action for applying a force proportional to the displacement speed are provided. Between the oil tank 40 and the cylinder 18,
An electromagnetic servo valve 44 and an oil pump 42 are provided.

When changing the attitude of the boom 4, the operation is as follows. The electromagnetic servo valve 44 is controlled by the CPU 50 to change the pressure of the cylinder 18 and set the angle of the first boom 6 to a desired angle. Second boom 8 and third boom 10
Is also the same. In this way, the boom 4 can be controlled to a desired posture.

Next, the operation of suppressing vibration after determining the attitude of the boom 4 will be described. A position sensor 52, which is a fluctuation detecting means for detecting the stroke x of the cylinder 18, is provided, and its output is given to the CPU 50. Further, a pressure sensor 54 for detecting the pressure of the cylinder 18 is provided, and its output is given to the servo amplifier 48.

In this embodiment, the solenoid servo valve 44 is not blocked. Therefore, when the boom 4 vibrates, the cylinder 18 moves accordingly and the stroke x thereof fluctuates. The sensor 52 detects this stroke x and gives it to the CPU 50. The CPU 50 takes in the given stroke x and calculates the target pressure F, which is the target driving force, according to the following equation.

F = F0-k (x-x0) -cx '... (1) where F0 is the driving force (pressure) during non-vibration, and k and c are coefficients. , X0 is the cylinder length without vibration, x is the cylinder length with vibration, and x'is the cylinder moving speed. The cylinder moving speed x ′ is obtained by dividing the change in the cylinder length x by the time.

The CPU 50 gives the calculated target pressure F to the servo amplifier 48 as a drive command. Servo amplifier 4
8 is also given the current cylinder 18 pressure.
The servo amplifier 48 gives an output according to the difference between the two to the electromagnetic servo valve 44, and controls the pressure of the cylinder 18 to match the target pressure F. That is, if the target pressure F is smaller than the pressure of the cylinder 18, the oil tank 40
Control is performed so that the oil is supplied to the oil tank 40, and if the target pressure F is higher than the pressure of the cylinder 18, the oil is discharged to the oil tank 40. Therefore, the pressure of the cylinder 18 is controlled to be equal to the target pressure F calculated by the CPU 50.

As described above, the cylinder pressure is F = F0
The meaning of controlling to be −k · (x−x0) −c · x ′ is as follows. The pressure when the electromagnetic servo valve 44 is blocked is F0. Therefore, the pressure Ff added by the above control is Ff = −k · (x−x
0) −c · x ′. Here, since x−x0 is a displacement amount, −k · (x−x0) is a spring element having a spring constant k. Further, −c · x ′ is a damper element having a damper coefficient c. That is, by controlling the pressure of the cylinder 18 according to the above equation, as shown in FIG.
8 can have a spring action 60 and a damper action 62.

In this embodiment, the CPU 50, the pressure sensor 54, the position sensor 52, the servo amplifier 48, and the electromagnetic servo valve 44 constitute the control means.

FIG. 4 shows frequency characteristics when the above control is performed. The spring action moves the resonance frequency fa to the lower side, as indicated by the broken line. The amount of movement can be controlled by adjusting the spring constant k. Therefore, by selecting the constant k, the resonance frequency fa can be deviated from the drive frequency of the squeeze pump (that is, the pulsating frequency of the fluid) to suppress vibration. In addition, due to the damper action, the gain near the resonance frequency is small, and in this respect also, vibration can be suppressed. In addition, the frequency characteristics of the phase also show a smooth continuous change without any abrupt change near the resonance point.

Another embodiment is shown in FIG. When changing the attitude of the boom 4, the solenoid valve 70 is controlled and the cylinder 1
The pressure of 8 is changed and the angle of the 1st boom 6 is made into a desired angle. The same applies to the second boom 8 and the third boom 10. In this way, the boom 4 can be controlled to a desired posture.

In this embodiment, a pressure increasing cylinder 72 which is an auxiliary cylinder is provided in addition to the cylinder 18 in order to have a spring effect and a damper effect. The position sensor 84 is
The stroke of the pressure boosting cylinder 72 is detected and given to the CPU 50. The strokes of the pressure boosting cylinder 72 and the cylinder 18 have a constant relationship depending on the pressure boosting ratio. Therefore, the CPU 50 calculates the stroke of the cylinder 18 based on the stroke of the pressure boosting cylinder 72. Based on this stroke x, the above equation (1) is calculated to calculate the target pressure F of the cylinder 18. The CPU 50 uses the target pressure F as an auxiliary drive command and the servo amplifier 82.
Output to.

On the other hand, the current pressure of the cylinder 18 detected by the pressure sensor 74 is also applied to the servo amplifier 82. The servo amplifier 82 gives an output according to the difference between the two to the electromagnetic servo valve 76, and controls the pressure of the cylinder 18 to match the target pressure F. That is,
If the target pressure F is lower than the pressure of the cylinder 18, oil is supplied from the oil tank 80, and if the target pressure F is higher than the pressure of the cylinder 18, the oil tank 8 is supplied.
The control is performed so that the oil is discharged to 0. Therefore,
The pressure of the cylinder 18 is controlled to be equal to the target pressure F calculated by the CPU 50.

Therefore, the same effect as that of the embodiment of FIG. 1 can be obtained. Further, according to the embodiment shown in FIG. 5, even if the control of the electromagnetic servo valve 76 becomes abnormal, the influence thereof remains within the stroke range of the electromagnetic servo valve 76. That is, there is no possibility that the boom 4 will operate abnormally over a wide range.

In each of the above embodiments, the rotational displacement of the joint is indirectly detected by detecting the stroke of the cylinder. However, the rotational displacement of the joint may be directly detected by detecting the angle of the boom (see θ in FIG. 2).

In the above embodiment, the rotational displacement of the joint is detected and the target driving force is calculated based on the detected rotational displacement. However, the rotational speed and the rotational acceleration are calculated by using the speed sensor and the acceleration sensor. May be detected, and the target driving force may be calculated based on this. Further, the target driving force may be calculated by combining these.

Further, in the above embodiment, as the driving means,
Although a hydraulic cylinder is used, other cylinders may be used. Further, a hydraulic motor or an electric motor may be used as the driving means.

In each of the above embodiments, the base joint 12
In the above, the above control is performed, but it may be performed in the intermediate joint portions 14 and 16. Also,
You may do both. However, the vibration of the cantilever is shown in Fig. 1.
As shown in 1, the root portion (that is, the base joint portion 12) in any of the primary, secondary, tertiary ...
Becomes an antinode of vibration. Therefore, if control is performed at the base joint 12 as in the above embodiment, it is easy to deal with vibrations in all modes.

Although the boom apparatus having the intermediate joint section has been described in the above embodiment, the present invention can be applied to a boom apparatus having an intermediate joint section such as a telescopic boom.

Further, although the squeeze pump is used as the delivery means in the above embodiment, a piston pump may be used.

Further, in the above embodiment, both the spring action and the damper action are added, but only one of them may be given.

FIG. 6A shows a block diagram according to another embodiment. In this embodiment, in addition to the control according to the embodiment shown in FIG. 1 or 5, the vibration suppression control is more positively performed. In each of the above embodiments, the CPU 50 obtains the target pressure F from the cylinder stroke amount output from the position sensor 84 (52). On the other hand, in this embodiment, the CPU 50 obtains the target pressure F by also taking into consideration the operation signal u which is the feed signal of the squeeze pump 90. The calculation formula is as follows. F = F
0-k ・ (x-x0) -c ・ x'-G ・ C-1 ・ u ...
(2) Here, G is the transfer function from the squeeze pump 90 to the tip of the boom 4 (or the one that identifies this) when there is no actuating signal u (see the schematic diagram of FIG. 7). C is a transfer function from the cylinder 18 to the tip of the boom 4 when there is no actuating signal u (or what is identified) (see the schematic diagram of FIG. 7).

Since the squeeze pump rotates by the actuation signal, the pulsation of concrete depends on this actuation signal u. Therefore, if the operation signal u and the transfer function G are given, the vibration at the tip of the boom 4 can be calculated. If an anti-phase vibration (anti-phase excitation force) can be applied to the calculated vibration, the vibration can be sufficiently suppressed. Therefore, the opposite vibration is generated by the boom 4
Cylinder 1 using the transfer function C as it occurs at the tip
It suffices to calculate the vibration (that is, the pressure change) to be given to the No. This is the above equation (2).

As shown in FIG. 4, since the frequency characteristic of the phase changes smoothly due to the spring action and the damper action, it is possible to apply the vibration of the opposite phase.
It is much easier than before. In addition, transfer functions G and C
Is measured by a vibration tester in advance and used.

Further, as shown in FIG. 6B, an acceleration sensor 98 which is a vibration detecting means attached to the tip of the boom 4.
It is also possible to use this signal as an error signal and correct G and C in equation (2) in real time. As a result, even if the predicted transfer functions G and C change due to changes in the attitude of the boom 4 or changes in the mixing ratio of concrete, it is possible to respond in real time and reliably suppress vibration. That is, as shown in the schematic diagram of FIG.
While using an adaptive filter having a transfer characteristic of W,
The transfer characteristic is changed by the LMS algorithm based on the error signal.

In each of the above embodiments, the case where the fluid is concrete has been described, but the present invention can be applied to other fluids.

In the fluid transport boom device according to this embodiment, the control means is provided with an auxiliary cylinder, and the pressure supply to the auxiliary cylinder is adjusted. Since the drive means is not directly controlled, even if a control abnormality occurs, the abnormal operation of the boom is suppressed within the drive range of the auxiliary cylinder, and the safety is high.

The boom device for fluid transportation of this embodiment is characterized in that the target driving force is obtained by adding the antiphase exciting force using the sending signal u of the transmission means to the control force based on the spring action or the damper action. There is. Therefore, the vibration of the tip portion can be suppressed more reliably. The boom device for fluid transportation of this embodiment is provided with a vibration detecting means at the tip of the boom to obtain a vibration signal, and the transfer function G / C used when calculating the inverse vibration force based on the detected vibration signal. It is characterized by the correction of -1 in real time. Therefore, the vibration of the tip portion can be suppressed more reliably.

[0043]

The boom device for fluid transportation according to the first and second aspects of the invention is effective against vibration of the boom due to pulsation of fluid flowing through the transportation path.
The spring frequency to shift the resonance frequency from the pulsating frequency of the fluid.
Damper that reduces the gain near the operating frequency or resonance frequency
It is characterized in that control means for controlling the driving force of the driving means is provided so as to produce the action . The damper action can increase the damping rate of the boom vibration and suppress the vibration. In addition, the vibration of the boom is suppressed by changing the resonance frequency of the boom by the spring action and shifting the resonance frequency of the boom from the pulsation frequency of the fluid.
Can be obtained.

According to another aspect of the fluid transportation boom device of the present invention, the fluctuation detecting means detects the fluctuation of the joint portion, the target driving force is calculated based on the detected fluctuation, and the target driving force is given to the driving means as a driving command. . Therefore, the spring action and the damper action can be provided by adjusting the supply of the driving force to the drive means.

[Brief description of drawings]

FIG. 1 is a diagram showing control means of a boom device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an external appearance of a boom device according to an embodiment of the present invention applied to a concrete truck.

FIG. 3 is a diagram schematically showing a spring action and a damper action according to the embodiment.

FIG. 4 is a diagram showing an improved state of frequency characteristics according to an embodiment.

FIG. 5 is a view showing control means of a boom device according to another embodiment.

FIG. 6 is a view showing control means of a boom device according to another embodiment.

FIG. 7 is a schematic operation diagram of a boom device according to another embodiment.

FIG. 8 is a schematic operation diagram of a boom device according to another embodiment.

FIG. 9 is a diagram showing an appearance of a conventional boom device.

FIG. 10 is a diagram showing frequency characteristics of the boom device.

FIG. 11 is a diagram showing a resonance mode of the boom device.

[Explanation of symbols]

18 ... Cylinder 44 ... Electromagnetic servo valve 50 ... CPU 52 ... Position sensor 54 ... Pressure sensor

   ─────────────────────────────────────────────────── ─── Continued front page       (56) References JP-A-5-230999 (JP, A)                 JP-A-5-98671 (JP, A)                 JP-A-1-276316 (JP, A)                 JP 62-114011 (JP, A)                 JP-A-5-141086 (JP, A)

Claims (3)

(57) [Claims] 1. A boom rotatably fixed to a main body by a base joint portion, a transportation path which is held by the boom and transports a fluid sent by a sending means to be discharged from a tip end portion, the base joint In a boom device for fluid transportation provided with a driving means for driving the boom driving point in the vertical direction, at least the following (1) against vibration of the boom due to pulsation of fluid flowing through the transportation path: Spring action or below
A boom device for fluid transportation, characterized in that a control means for controlling the driving force of the driving means is provided so as to generate any one of the damper actions shown in (2) , (1) the fluid flowing through the transportation path. Resonance caused by pulsation
The frequency is calculated from the pulsating frequency of the fluid flowing through the transportation path.
Spring action, (2) Resonance caused by pulsation of fluid flowing through the transport path
Damper action that reduces the gain near the frequency. 2. A boom which is rotatably fixed to a main body by a base joint portion and has an intermediate joint portion at an intermediate portion with respect to the entire length; A transport path for discharging fluid from a portion, a drive means provided in the base joint section and the intermediate joint section, and driving the boom drive point in the up-and-down direction. With respect to the vibration of the boom due to pulsation, at least the following spring action (1) or the following (2)
A fluid transportation boom device, wherein at least one of the joint portions is provided with control means for controlling the driving force of the driving means so as to cause any one of the damper actions of (1) the transportation path. Resonance caused by pulsation of fluid flowing in
The frequency is calculated from the pulsating frequency of the fluid flowing through the transportation path.
Spring action, (2) Resonance caused by pulsation of fluid flowing through the transport path
Damper action that reduces the gain near the frequency. 3. The boom apparatus for fluid transportation according to claim 1, wherein the control means directly or indirectly determines at least one of rotational displacement, rotational speed, or rotational acceleration of the joint portion. Variation detecting means for detecting, driving force detecting means for detecting the driving force of the driving means, computing means for computing the target driving force based on the variation detected by the variation detecting means, and outputting as a driving command, driving force detecting means And a drive force adjusting unit that adjusts the supply of the drive force to the drive unit so that the drive force detected by the drive unit matches the target drive force given as the drive command. apparatus.