JP7601693B2 - Leveling device - Google Patents

Description

The present invention relates to construction machinery, such as lifting devices such as balance arms, and in particular to a leveling device for maintaining the level of the work equipment of the construction machinery.

A balance arm, which is an example of a lifting device in construction machinery, includes a link mechanism and an auxiliary power source (an actuator such as an air motor or an electric motor), and even if a heavy load is attached to the tip, the heavy load can be moved with only a small force. For example, the balance arm is used widely in factories to support processing machines (see, for example, Patent Document 1).
Here, in construction machinery such as lifting devices, if the working equipment is not kept horizontal, for example in the case of a balance arm of the lifting machine, the main shaft will rotate freely, causing the position of the tip of the balance arm that suspends a heavy load to become unstable and making it difficult for the worker to adjust the tip position due to the load caused by the heavy load.

At construction sites, attempts have been made to use, for example, a balance arm as a lifting device to move heavy objects such as blocks with minimal effort by workers.
However, at construction sites, the ground is very uneven and the slope is not uniform, making it difficult to ensure that the balance arm is in a horizontal position and to use the balance arm to handle heavy loads and move freely up and down.

Japanese Utility Model Application Publication No. 61-85336

The present invention has been proposed in consideration of the problems with the conventional technology described above, and aims to provide a leveling device that can maintain the level of the work equipment of construction machines, such as lifting devices such as balance arms, even on construction sites where the ground is very uneven, the slope is non-uniform, and there are many so-called "unstable areas."

The leveling device (10) of the present invention is a leveling device (10) for keeping a base (21) of a working device (e.g., a balance arm 20) of a construction machine (30) in a horizontally fixed state,
A control target plate (1) to which a working device (20) of a construction machine (30) is fixed (for example, a base portion 21 of a balance arm 20 is fixed) is a plate-like member having a substantially triangular shape;
Actuators (R, L, C: for example, a piston-cylinder mechanism, a jack mechanism, or other telescopic mechanism) arranged at positions corresponding to the vertices of a triangle on the control target plate (1),
A measuring device (2: X-axis tilt angle sensor 2A, Y-axis tilt angle sensor 2B) for measuring the tilt of a control target plate (1);
a control device (3: control unit) that determines the amount of expansion or contraction of the actuators (R, L, C) based on the measurement results of the measuring device (2);
The control device (3)
a function of calculating a virtual amount of extension or contraction (a provisional amount of extension or a provisional amount of contraction) of the other two actuators (e.g., actuators L and C) so that the control target plate (1) becomes horizontal with one of the actuators (R, L, C) (e.g., actuator R) fixed in a neutral position;
A function of calculating a correction value (F: allocation correction value) based on the calculated virtual extension or contraction amount so that the position after extension or contraction of the actuator (R, L, C) approaches the neutral position;
a function of calculating a correction value based on the calculated virtual extension or contraction amount so as to reduce the extension or contraction amount of two actuators (e.g., actuator L, C) other than the actuator (e.g., actuator R) fixed at the neutral position to less than the virtual extension or contraction amount, and calculating the extension or contraction amount of each of the actuators (e.g., actuator R) fixed at the neutral position and the other two actuators (e.g., actuator L, C) from the virtual extension or contraction amount and the correction value,
The control device (3) is characterized by having a function of extending or retracting the actuators, which have been extended or retracted by horizontal maintenance control, simultaneously, in the same direction, and by the same distance, once or multiple times .
Here, horizontal maintenance control refers to control in which the control target plate (1) is supported horizontally by a plurality of actuators (for example, actuators R, L, and C).
In addition, the term "neutral position" is used in this specification to mean a state in which the actuator (R, L, C) is extended by half the maximum extension amount (stroke: for example, 120 mm) (for example, extended by 60 mm). In the neutral position, both the extension amount and the contraction amount are maximum.
The X-axis tilt angle sensor (2A) and the Y-axis tilt angle sensor (2B) may be collectively referred to as the "measurement device (2)".
The leveling device (10) of the present invention is a leveling device (10) for keeping a base (21) of a working device (e.g., a balance arm 20) of a construction machine (30) in a horizontally fixed state,
A control target plate (1) to which a working device (20) of a construction machine (30) is fixed (for example, a base portion 21 of a balance arm 20 is fixed) is a plate-like member having a substantially triangular shape;
Actuators (R, L, C: for example, a piston-cylinder mechanism, a jack mechanism, or other telescopic mechanism) arranged at positions corresponding to the vertices of a triangle on the control target plate (1),
A measuring device (2: X-axis tilt angle sensor 2A, Y-axis tilt angle sensor 2B) for measuring the tilt of a control target plate (1);
a control device (3: control unit) that determines the amount of expansion or contraction of the actuators (R, L, C) based on the measurement results of the measuring device (2);
The control device (3)
a function of calculating a virtual amount of extension or contraction (a provisional amount of extension or a provisional amount of contraction) of the other two actuators (e.g., actuators L and C) so that the control target plate (1) becomes horizontal with one of the actuators (R, L, C) (e.g., actuator R) fixed in a neutral position;
A function of calculating a correction value (F: allocation correction value) based on the calculated virtual extension or contraction amount so that the position after extension or contraction of the actuator (R, L, C) approaches the neutral position;
a function of calculating a correction value based on the calculated virtual extension or contraction amount so as to reduce the extension or contraction amount of two actuators (e.g., actuator L, C) other than the actuator (e.g., actuator R) fixed at the neutral position to less than the virtual extension or contraction amount, and calculating the extension or contraction amount of each of the actuators (e.g., actuator R) fixed at the neutral position and the other two actuators (e.g., actuator L, C) from the virtual extension or contraction amount and the correction value,
The control device (3) is characterized by having a function of keeping all of the actuators (R, L, C) in a neutral position when the work implement (20) of the construction machine (30) is not in use.

In the present invention, the leveling device (10) (and the balance arm 20) is preferably mounted on a construction machine (30).
In addition, it is preferable that the control device (3) has a function of setting the correction value (F: allocation correction value) to be half the value obtained by adding the maximum virtual expansion amount (positive value) to the minimum virtual contraction amount (negative value).

In addition, it is preferable that the control device (3) has a function of increasing or decreasing the amount of extension or contraction of all actuators (R, L, C) by a predetermined value (δ) when the actual amount of extension or contraction of any of the actuators (R, L, C) is equal to or less than a predetermined value (δ: for example, 5 mm) (minimum stroke correction control: Figure 11).

In addition, in the method using the horizontal maintenance device of the present invention (10: the horizontal maintenance device according to any one of claims 1 to 6),
In order to keep the working device (e.g., the base 21 of the balance arm 20) of the construction machine (30) horizontally fixed,
a provisional expansion/contraction amount calculation step of calculating a provisional expansion or contraction amount (provisional expansion amount or provisional contraction amount) of the other two actuators (e.g., actuators L and C) so that the control target plate (1) is horizontal with one of the actuators (R, L, C) (e.g., actuator R) fixed in a neutral position;
a correction value calculation step of calculating a correction value (F: allocation correction value) based on the calculated virtual extension or contraction amount so that the position after extension or contraction of the actuator (R, L, C) approaches a neutral position;
The method is characterized by comprising a step of calculating the amount of expansion or contraction of the actuators (R, L, C) from the virtual amount of expansion or contraction and the correction value (F).

The method of the present invention is preferably carried out on a construction machine (30) equipped with the leveling device (10) and a working device (balance arm 20).

In the method of the present invention, the correction value calculation step comprises:
It is preferable to determine the correction value (F: allocation correction value) as half the sum of the maximum virtual expansion amount (positive value) and the minimum virtual contraction amount (negative value).

In the method of the present invention,
It is preferable to have a step of increasing or decreasing the amount of extension or contraction of all the actuators (R, L, C) by a predetermined value (δ: for example, 5 mm) when the actual amount of extension or contraction of any of the actuators (R, L, C) is less than a predetermined value (δ) (see FIG. 11).

Alternatively, it is preferable to have a process in which the actuators (R, L, C) that have been expanded or contracted to horizontally support the control target plate (1) are expanded or contracted simultaneously, in the same direction, and by the same distance (σ: for example, 5 mm) once or multiple times (see Figure 12).

Furthermore, when the working device (20) of the construction machine (30) is not being used (for example, when the construction machine 30 equipped with the balance arm 20 is moved to a storage location after work using the construction machine 30 is completed), it is preferable to keep all of the actuators (R, L, C) in the neutral position (see FIG. 13).

According to the present invention having the above-mentioned configuration, the level maintenance device (10) is mounted on the construction machine (30) in order to keep the working device (e.g., the base 21 of the balance arm 20) of the construction machine (30) fixed horizontally. Even when the construction machine (30) is used on a site with so-called "bad footing" or a site with a large amount of unevenness, the base of the working device (20) of the construction machine (30) is kept horizontal, thereby ensuring that the function of the working device (20) of the construction machine (30) is fully performed, and thus the worker can easily perform work such as suspending heavy objects using the working device (e.g., the balance arm 20) of the construction machine (30).
Then, in order to make the controlled plate (1) horizontal with one of the actuators (R, L, C) (for example, actuator R) fixed in the neutral position, a virtual extension or contraction amount (tentative extension or contraction amount) of the other two actuators (for example, actuators L and C) is calculated, and a correction value (F: allocation correction value) is calculated based on the calculated virtual extension or contraction amount so that the position of the actuators (R, L, C) after extension or contraction approaches the neutral position. Then, the (actual) extension or contraction amount of the actuators (R, L, C) is calculated from the virtual extension or contraction amount and the correction value (F). Therefore, there is no need to execute complex control, and the working device (for example, the base 21 of the balance arm 20) of the construction machine (30) and the controlled plate (1) to which it is fixed can be supported horizontally without placing a large load on the control device (3).
Furthermore, a correction value (F: allocation correction value) is calculated based on the calculated virtual extension or contraction amount, and the (actual) extension or contraction amount of the actuators (R, L, C) is calculated from this correction value (F). This makes it possible to ensure a margin for extension or contraction of the actuators (R, L, C), and prevents unrealizable control that exceeds the maximum stroke (extension or contraction amount) of the actuators (R, L, C).

In the present invention, when the actual amount of extension or contraction of any of the actuators (R, L, C) is less than a predetermined value (δ: for example, 5 mm), by increasing or decreasing the amount of extension or contraction of all of the actuators (R, L, C) by the predetermined value (δ), it is possible to prevent a situation in which the actual amount of extension or contraction of the actuators (R, L, C) becomes too small and control becomes difficult.
Furthermore, in the present invention, if the actuators (R, L, C) that have been extended or contracted to support the control target plate (1) horizontally are extended or contracted simultaneously in the same direction by the same distance (σ: for example, 5 mm) once or multiple times, each actuator (R, L, C) will either extend or contract more than the target extension amount or contract more than the target contraction amount, which will result in an error occurring between the actuators (R, L, C) after extension or contraction, and the control target plate (1) will not tilt (will not be able to be supported in a horizontal state).
Alternatively, in the present invention, when the working device (20) of the construction machine (30) is not being used (for example, when the construction machine (30) equipped with the balance arm 20 is moved to a storage location after work using the construction machine (30) is completed), by keeping all of the actuators (R, L, C) in a neutral position, even if vibrations caused by uneven ground occur, the vibrations can be prevented from adversely affecting the actuators (R, L, C) and the control target plate (1), and the risk of distortion or the like occurring in the working device (20) of the construction machine (30) can be reduced.

1 is an explanatory diagram showing a construction machine to which an embodiment of the present invention is applied; FIG. 1 is a plan view of a horizontal maintenance device according to an embodiment of the present invention. FIG. 3 is a side view taken along the line AC in FIG. 2 . FIG. 2 is an explanatory diagram showing the principle of horizontal maintenance control in the present invention. 5 is an explanatory diagram showing the principle of horizontal maintenance control, similar to FIG. 4. 4 and 5, this is an explanatory diagram showing the principle of horizontal maintenance control. 4 to 6, this is an explanatory diagram showing the principle of horizontal maintenance control. FIG. 2 is a functional block diagram of a control unit in the embodiment. 5 is a flowchart showing horizontal maintenance control in the embodiment. 10 is a flowchart showing the horizontal maintenance control in the embodiment, which is a flowchart following the steps shown in FIG. 9 . 5 is a flowchart showing a minimum stroke correction control in the illustrated embodiment. 10 is a flowchart showing a repeat movement control in the illustrated embodiment. 5 is a flowchart showing neutral position maintaining control in the illustrated embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In the illustrated embodiment, a balance arm is illustrated as an example of a working device of a construction machine.
FIG. 1 shows a construction machine 30 equipped with a balance arm 20 (working device of the construction machine) equipped with a level maintenance device 10 according to an embodiment of the present invention.
1, a construction machine 30 equipped with a balance arm 20 serving as a working device is equipped with caterpillar tracks 33, and the balance arm 20 is provided behind (in the direction of the arrow RR) a driver's seat 31 of the construction machine 30. The balance arm 20 itself is configured by combining a four-bar link mechanism and an actuator, as in the prior art, and even if a heavy load 40 such as a concrete block is loaded, the heavy load 40 can be easily moved manually by an operator.
The horizontal maintenance device 10 includes a control target plate 1, actuators R, L, and C, and a control unit 3 (not shown; see Figs. 2 and 8).
A flat platform 32 is provided behind (in the direction of arrow RR) a driver's seat 31 of the construction machine 30, and a plurality of actuators R, L, and C (only actuators L and C are shown in FIG. 1) are arranged on the platform 32.
A controlled plate 1 is attached to the rod tips of actuators R, L, and C (sometimes referred to as "actuator tips" in this specification). Although not clearly shown, a base 21 of a balance arm 20 is fixed to the controlled plate 1 via a flange. The controlled plate 1 is an object that is kept horizontal by control in the illustrated embodiment, and is a roughly triangular plate-like member.

The control target plate 1 is held horizontally by a plurality of actuators R, L, and C (three in the illustrated embodiment) when the construction machine 30 is stopped and fixed at the work site.
The actuators R, L, C supporting the controlled plate 1 are maintained in a neutral position when no work is being performed by the balance arm 20. This will be described later with reference to FIG.
The term "neutral position" is used herein to indicate a state in which the actuators R, L, and C are extended by half the maximum extension or contraction amount (stroke: for example, 120 mm) (for example, extended by 60 mm). In the neutral position, the extension or contraction amount from there is maximized.

2, which is a plan view of the level maintenance device 10 according to the illustrated embodiment, the controlled plate 1 has a roughly triangular planar shape, with actuators R, L, and C disposed at each of the apexes of the triangle. In other words, each of the apexes of the triangle of the controlled plate 1 is supported by the actuator tips (rod tips) of the actuators R, L, and C. An arrow FR indicates the front of the construction machine 30 (FIG. 1), and an arrow RR indicates the rear of the construction machine 30.
An X-axis tilt angle sensor 2A that detects tilt in the forward/backward direction (X-axis direction) and a Y-axis tilt angle sensor 2B that detects tilt in the left/right direction (Y-axis direction) are arranged on the control target plate 1, and the detection results of the X-axis tilt angle sensor 2A and the Y-axis tilt angle sensor 2B are transmitted to a control unit 3 (control device) via signal transmission lines SL1 and SL2, respectively.
2 shows the X-axis direction distance _LX between the actuators R and C, and the Y-axis direction distance _LY between the actuators R and L. The X-axis direction distance _LX and the Y-axis direction distance _LY are stored in the memory block 3B (FIG. 8) of the control unit 3 (control device). As will be described later with reference to FIG. 8, control signals from the control unit 3 to the actuators R, L, and C are transmitted via signal transmission lines SL12-1, SL12-2, and SL12-3, respectively.
Actuator C is located at the rear end (end in the direction of arrow RR: upper end in Fig. 2) of controlled plate 1. In Fig. 3, which is a side view seen from the direction of arrow AC in Fig. 2, actuator R is located at the right end of controlled plate 1 (left end in Fig. 2), and actuator L is located at the left end in Fig. 3 (right end in Fig. 2).

The actuators R, L, C are fluid pressure actuators (e.g. hydraulic cylinders) and, in Fig. 3, are disposed on the mounting portion 32 (Fig. 1) of the construction machine 30. The upper ends of the actuators R, L, C are axially supported so as to be freely rotatable relative to the control target plate 1.
Each of the actuators R, L, C is provided with a potentiometer 4 for measuring the amount of expansion or contraction, and is also fitted with a stopper (not shown) to prevent the actuators from falling over.

An overview of keeping the control target plate 1 horizontal in the horizontal maintenance control in the illustrated embodiment will be described with reference to Figures 4 to 7. Here, the term "horizontal maintenance control" refers to control for supporting the control target plate 1 horizontally using three actuators R, L, and C.
For ease of explanation, specific numerical values are given as examples in Fig. 4 to Fig. 7. Also, since the controlled plate 1 shown in Fig. 4 to Fig. 7 is inclined with respect to the horizontal plane, the lateral positions of actuator R and actuator L (left-right positions in Fig. 4 to Fig. 7) do not match in Fig. 4 to Fig. 7.
In addition, the provisional contraction or extension described below with reference to Figures 4 to 6 is based on the apex of actuator R. Therefore, in Figures 4 to 6, actuator R does not expand or contract from the neutral position, but is fixed at the neutral position. However, it is of course possible to control the actuator not to expand or contract from the neutral position by using apex L (actuator L) or apex C (actuator C) instead of apex R as the reference.

In Fig. 4, the inclined ΔRLC corresponds to the controlled plate 1 that is the target of horizontal maintenance control. As described above, the vertices of actuators R, L, and C are respectively located at the vertices of the controlled plate 1, and therefore in Figs. 4 to 7, the vertices of ΔRLC are expressed as vertex R, vertex L, and vertex C. In Figs. 4 to 7, the up and down direction indicates the height position of the tips of actuators R, L, and C that support the controlled plate 1, and a change in this height position means that actuators R, L, and C are expanding or contracting. In the example shown in Figs. 4 to 7, in the state immediately before horizontal maintenance control is performed, as shown in Fig. 4,
The apex L is 52 mm above the apex R.
The apex C is 43 mm above the midpoint M of the apex RL.
At this point, the actuators R, L, and C are extended by half the stroke (120 mm) (neutral position).

When the actuator L is contracted by 52 mm (a provisional contraction amount) from the state shown in Fig. 4, the apex R and the apex L become horizontal as shown in Fig. 5. The contraction of the actuator L is indicated by an arrow P in Fig. 5.
By contracting the actuator L, the vertices R and L become horizontal, and the midpoint M of the vertices R and L moves downward by 26 mm (=52÷2). As a result, in FIG. 5, the vertex C is located 69 mm (=43 mm+26 mm) above the midpoint M (vertices R and L).

If actuator C is contracted by 69 mm (tentative contraction amount) from the state in Fig. 5 (arrow Q in Fig. 6), then vertices R, L, and C become horizontal, and the controlled plate 1 becomes horizontal, as shown in Fig. 6. In other words, if actuator L is contracted by the tentative contraction amount of 52 mm and actuator C is contracted by the tentative contraction amount of 69 mm, the controlled plate 1 is supported horizontally.
Here, since the provisional contraction amount is determined based on the vertex R (so that the vertex R does not move), the provisional expansion/contraction amount of the actuator R is zero.
The provisional expansion and contraction amount of each actuator is
Actuator R is 0 mm (does not extend or contract)
Actuator L contracts by 52 mm, and actuator C contracts by 69 mm. If actuator L contracts by 52 mm, the contraction margin of actuator L (maximum 60 mm from the neutral position) becomes small, which is not preferable. Also, it is impossible to contract actuator C by 69 mm from the neutral position.
In the illustrated embodiment, in the controlled plate 1 which is supported horizontally when assumed to have expanded or contracted by a provisional contraction or extension amount, the actual contraction or extension amount is corrected (with respect to the provisional contraction or extension amount) to bring the actuators R, L, C after the actual expansion or contraction closer to the neutral position, thereby providing a margin for each expansion or contraction.

In the following, an extension amount or provisional extension amount is expressed as a "positive" numerical value, and a contraction amount or provisional contraction amount, which is a displacement in the opposite direction, is expressed as a "negative" numerical value. In this specification, regardless of whether a numerical value is "positive" or "negative", a numerical value with a large absolute value is described as being larger than a numerical value with a small absolute value, and a numerical value with a small absolute value is described as being smaller than a numerical value with a large absolute value.
By expanding or contracting the three actuators R, L, and C by the same distance (the same amount), it is possible to bring the actuators R, L, and C closer to the neutral position while maintaining ΔRLC (the controlled plate 1) in the horizontal state shown in FIG. 6, thereby providing a margin for each expansion or contraction.
Therefore, for actuators R, L, and C, the sum of the provisional extension amount of the actuator with the smallest provisional extension amount (actuator R: provisional extension amount +0 mm) and the provisional contraction amount of the actuator with the largest provisional contraction amount (actuator C: provisional contraction amount -69 mm) is calculated (0 + (-69) = -69 mm), and half of this sum (-69 mm) (-69/2 = -34.5 mm) is set as the correction value F (allocation correction value). The numerical values obtained by subtracting the allocation correction value F from the provisional extension amounts and provisional contraction amounts of all three actuators described with reference to Figure 6 are set as the target values for the expansion and contraction of the actuators. In other words,
Actuator R → 0 - (-34.5) = 34.5 mm (extension)
Actuator L → -52 - (-34.5) = -17.5 mm (contraction)
Actuator C → -69 - (-34.5) = -34.5 mm (contraction)
FIG. 7 shows the target values of expansion and contraction of each actuator corrected by the distribution correction value F (−34.5 mm).

Here, in the explanation with reference to Figures 4 to 6, the terms "extension" and "contraction" refer to operations or virtual space, and the actual actuators R, L, and C are not extended or contracted at the stages shown in Figures 4 to 6.
If the actual expansion or contraction amounts of the actuators R, L, and C are calculated by subtracting the correction value F (distribution correction value) from the provisional contraction amount (or provisional expansion amount), then each of the actuators R, L, and C will expand or contract to the calculated actual expansion or contraction amount (target value) as shown in Figure 7. The actual expansion or contraction amount, not the provisional contraction or provisional expansion amount, of the actuators R, L, and C is expressed as follows:
Actuator R extends by 34.5 mm Actuator L retracts by 17.5 mm Actuator C retracts by 34.5 mm When actuators R, L, and C are extended or contracted in this manner, as shown in FIG. 7, ΔRLC (controlled plate 1) becomes horizontal, and after extension or contraction actuators R, L, and C are close to the neutral position, with a margin compared to the state in FIG. 6.

Fig. 8 is a functional block diagram of the control unit 3 (control device) which executes the horizontal maintenance control outlined with reference to Fig. 4 to Fig. 7. In Fig. 8, the control unit 3 has an actuator tip position specifying block 3A, a memory block 3B, a first actuator tentative expansion/contraction amount determining block 3C, a second actuator tentative expansion/contraction amount determining block 3D, a maximum tentative extension amount/minimum tentative contraction amount determining block 3E, a tentative expansion/contraction amount correction value determining block 3F, an expansion/contraction amount determining block 3G for actuators R, L, C, a minimum stroke correction block 3H, a controlled plate repeated movement block 3I, and a neutral position maintaining block 3J.
8 to 13, in level maintenance control, the apex of actuator R is used as a reference (apex R is fixed at a neutral position) and the values of apexes L and C of the other actuators are calculated in the same manner as described with reference to Figs. 4 to 7. The "first actuator" in the first actuator provisional expansion/contraction amount determination block 3C is "actuator L," and the "second actuator" in the second actuator provisional expansion/contraction amount determination block 3D is "actuator C."

The actuator tip position identifying block 3A acquires a measurement signal of the X-axis tilt angle _θX from the X-axis tilt angle sensor 2A (see FIG. 2) via a signal transmission line SL1, and acquires a measurement signal of the Y-axis tilt angle _θY from the Y-axis tilt angle sensor 2B (see FIG. 2) via a signal transmission line SL2. The actuator tip position identifying block 3A acquires the X-axis distance _LX (see FIG. 2) between actuators R and C and the Y-axis distance LY (see FIG. 2) between actuators R and L from the memory block _3B via a signal transmission line SL3.
The actuator tip position identification block 3A has a function of identifying the tip position of each of the actuators R, _L , and C based on the acquired X-axis tilt angle _θX , Y-axis tilt angle _θY , X-axis distance _LX between the actuators R and C, and Y-axis distance LY between the actuators R and L.
Although not shown in the figure, at the beginning of horizontal maintenance control, the actuator tip position identification block 3A is capable of transmitting information to a receiver from the actuators R, L, C that the actuators R, L, C are in neutral positions via the potentiometer 4.
Once the tip positions of the actuators R, L, C have been determined by the actuator tip position determination block 3A, the tip positions are transmitted to the first actuator tentative extension/contraction amount determination block 3C via a signal transmission line SL4, and to the second actuator tentative extension/contraction amount determination block 3D via a signal transmission line SL5. As will be described later, it is preferable to transmit the tip positions of the actuators R, L, C to the comparison block 3L.

The memory block 3B records data necessary or effective for horizontal maintenance control, such as the X-axis distance _LX between the actuators R and C and the Y-axis distance L _Y between the actuators R and L. The memory block 3B can also record the results of calculations and decisions made by each control block.
The data stored in the memory block 3B is transmitted to each functional block as necessary. To avoid complicating Fig. 8, arrows and the like indicating transmission and reception of signals in the memory block 3B are omitted.

8, the first actuator tentative expansion/contraction amount determination block 3C has a function of calculating and determining a tentative expansion/contraction amount δ RL of the actuator L (first actuator) based on the tip position information (X-axis tilt angle θ _X , Y-axis tilt angle θ _Y , X-axis distance L _X between actuators R and C, and Y-axis distance L _Y between actuators R and L) of the first actuator (actuator L), the second actuator (actuator C), and actuator _R obtained from the actuator tip position identification block 3A.
The provisional expansion/contraction amount δ _RL of the actuator L (first actuator) is expressed by the following formula: δ _RL = L _Y Sin θ _Y
(See step S2 in the flow chart of FIG. 9).
The calculation result of the temporary expansion/contraction amount δ _RL of the actuator L (first actuator) by the first actuator temporary expansion/contraction amount determination block 3C is transmitted to the maximum temporary extension amount/minimum temporary contraction amount determination block 3E via a signal transmission line SL6, and is transmitted to the expansion/contraction amount determination block 3G of the actuators R, L, C via a signal transmission line SL7.

The second actuator tentative expansion/contraction amount determination block 3D has a function of calculating and determining a tentative expansion/contraction amount δ RC of actuator C (second actuator) based on the tip position information (X-axis tilt angle θ _X , Y-axis tilt angle θ _Y , X-axis distance L _X between actuators R and C, and Y-axis distance L _Y between actuators R and L) of the first actuator (actuator L), the second actuator (actuator C), and actuator _R acquired from the actuator tip position identification block 3A.
The provisional expansion/contraction amount δ _RC of the actuator C (second actuator) is expressed by the following formula: δ _RC = L _X Sin θ _X + (1/2) L _Y Sin θ _Y
(Step S2 in the flow chart of FIG. 9).
The second term on the right side of the calculation formula for the provisional expansion/contraction amount δ _RC, “(½)L _Y Sin θ _Y ”, is the expansion/contraction amount of the midpoint M (see FIGS. 4 to 7) of the vertex RL.
The calculation result of the provisional expansion/contraction amount δ _RC of actuator C (second actuator) by the second actuator provisional expansion/contraction amount determination block 3D is transmitted to the maximum provisional extension amount/minimum provisional contraction amount determination block 3E via a signal transmission line SL8, and is transmitted to the expansion/contraction amount determination block 3G of actuators R, L, C via a signal transmission line SL9.

In FIG. 8, the maximum provisional extension amount/minimum provisional contraction amount determination block 3E has the function of determining the maximum provisional extension amount (a "positive" value) and the minimum provisional contraction amount (a contraction amount with the largest absolute value: a "negative" value) for the provisional expansion/contraction amount δ _RL (actuator L), the provisional expansion/contraction amount δ _RC (actuator C), and the provisional expansion _/ contraction amount 0 (the provisional expansion/contraction amount with the largest absolute value, a "negative" value) based on the calculation result of the provisional expansion/contraction amount δ _RL of actuator L (first actuator) obtained from the first actuator provisional expansion/contraction amount determination block 3C and the calculation result of the provisional expansion/contraction amount δ RC of actuator C (second actuator) obtained from the second actuator provisional expansion/contraction amount determination block 3D.
The maximum temporary extension amount and the minimum temporary contraction amount determined in the maximum temporary extension amount/minimum temporary contraction amount determination block 3E are transmitted to the temporary expansion/contraction amount correction value determination block 3F via a signal transmission line SL10.

The temporary expansion/contraction amount correction value determination block 3F has a function of determining an allocation correction value F, which is a correction value for the temporary expansion/contraction amount, based on the maximum temporary extension amount and the minimum temporary contraction amount obtained from the maximum temporary expansion amount/minimum temporary contraction amount determination block 3E. As described with reference to Figures 4 to 7, the allocation correction value F is set so that the control target plate 1 is horizontal and the positions of the actuators R, L, C after extension or contraction are close to the neutral position. The allocation correction value F is calculated based on the maximum temporary extension amount and the minimum temporary contraction amount determined by the maximum temporary expansion amount/minimum temporary contraction amount determination block 3E. The calculation formula for the allocation correction value F is the following formula: Correction value F = {(maximum temporary extension amount) + (minimum temporary contraction amount)}/2
(The maximum tentative stretch amount is a "positive" value, and the minimum tentative shrink amount is a "negative" value.)
The distribution correction value F determined in the temporary expansion/contraction amount correction value determination block 3F is transmitted to the expansion/contraction amount determination block 3G for the actuators R, L, C via a signal transmission line SL11.

The actuator R, L, C expansion/contraction amount determination block 3G has a function of correcting the calculation result of the provisional expansion/contraction amount δ _RL of actuator L (first actuator) obtained from the first actuator provisional expansion/contraction amount determination block 3C and the calculation result of the provisional expansion/contraction amount δ _RC of actuator C (second actuator) obtained from the second actuator provisional expansion/contraction amount determination block 3D based on the allocation correction value F (provisional expansion/contraction amount correction value) obtained from the provisional expansion/contraction amount correction value determination block 3F, and calculating and determining the actual expansion/contraction amounts of the actuators R, L, C. The actual expansion/contraction amounts of the actuators R, L, C are calculated by the following equation.
Actual expansion/contraction amount of actuator L=(provisional expansion/contraction amount of actuator L δ _RL )−(distribution correction value F)
Actual expansion/contraction amount of actuator C=(provisional expansion/contraction amount of actuator C δ _RC )−(distribution correction value F)
Actual expansion/contraction amount of actuator R=(provisional expansion/contraction amount of actuator R 0)−(distribution correction value F)
The result of the determination of the actual amount of expansion/contraction of the actuators R, L, C by the expansion/contraction amount determination block 3G is transmitted to the comparison block 3L via a signal transmission line SL12.

The comparison block 3L receives the tip positions of the actuators R, L, and C determined by the actuator selection position determination block 3A. Alternatively, the comparison block 3L can receive the measurement results from the potentiometer 4 and determine the tip positions of the actuators R, L, and C based on the measurement results. The comparison block 3L has a function of comparing the determination results of the actual amount of expansion/contraction input from the expansion/contraction amount determination block 3G with the tip positions of the actuators R, L, and C from the actuator selection position determination block 3A (or determined based on the measurement results from the potentiometer 4). The comparison block 3L has a function of transmitting the comparison results to the expansion/contraction control signal generation block 3M via the signal transmission line SL21.
The expansion/contraction control signal generating block 3M has a function of generating and transmitting an expansion or contraction control signal for each of the actuators R, L, and C based on the comparison result of the comparison block 3L. The expansion or contraction control signal generated by the expansion/contraction control signal generating block 3M is transmitted to each of the actuators R, L, and C via the signal transmission lines SL12 (SL12-1, SL12-2, SL12-3), and each of the actuators R, L, and C expands or contracts in accordance with the control signal.

8, the minimum stroke correction block 3H has the function of acquiring the determination results of the actual expansion/contraction amounts of the actuators R, L, C from the expansion/contraction amount determination block 3G for the actuators R, L, C via a signal transmission line SL13, and executing the minimum stroke correction control (see FIG. 11) described below. The correction result (predetermined value δ) by the minimum stroke correction block 3H is sent to the expansion/contraction amount determination block 3G for the actuators R, L, C via a signal transmission line SL14.
The control plate repeated movement block 3I has a function of executing a control of the control plate repeated movement (see FIG. 12) described later, based on an input signal transmitted from the horizontal AUTO switch 5 manually input by an operator via a signal transmission line SL15. The control content (predetermined value σ) determined by the control plate repeated movement block 3I is transmitted to the expansion/contraction amount determination block 3G for the actuators R, L, C via a signal transmission line SL16 .
The neutral position maintaining block 3J has a function of receiving an operation signal from the operation panel 6 transmitted via a signal transmission line SL17 and executing a neutral position maintaining control (see FIG. 13) described later. The neutral position control signal determined by the neutral position maintaining block 3J is transmitted to the expansion/contraction amount determination block 3G of the actuators R, L, C via a signal transmission line SL18.

With reference to FIG. 8, the procedure of the horizontal maintenance control outlined in FIG. 4 to FIG. 7 will be described mainly based on FIG. 9 and FIG.
9, in step S1, the actuator tip position identification block 3A obtains from the memory block 3B the X-axis distance _LX between actuators R and C and the Y-axis distance LY between actuators R and L, as well as _{the X-axis tilt angle θX from} the X-axis tilt angle sensor 2A and the Y-axis tilt angle _θY from the Y-axis tilt angle sensor 2B. As described above, the X-axis distance _LX between actuators R and C, the Y-axis distance LY between actuators R and _L , the X-axis tilt angle _θX , and the Y-axis tilt angle _θY are parameters for identifying the tip positions of each of the actuators R, L, and C.
Then proceed to step S2.

In step S2, a tentative extension amount δ _RL of actuator L (first actuator) is calculated based on the data acquired in step S1, and a tentative extension amount δ _RC of actuator C (second actuator) is calculated. In the illustrated embodiment, since actuator R is fixed in a neutral position as a reference, the tentative extension amount is 0 (zero).
As described above, the provisional expansion/contraction amount δ _RL of the actuator L (first actuator) is calculated by the following equation: δ _RL = L _Y sin θ _Y.
The provisional expansion/contraction amount δ _RC of actuator C (second actuator) is calculated by the following equation: δ _RC = L _x sin θ _x + (½) L _y sin θ _Y. The second term on the right hand side of the equation for provisional expansion/contraction amount δ _RC is the provisional expansion/contraction amount δ _RM of the midpoint M (FIG. 4 and others) of the vertex RL, and the provisional expansion/contraction amount δ _RM is calculated by the following equation.
δ _RM = (1/2)L _Y Sinθ _Y
The calculation of the provisional expansion/contraction amount δ _RL of actuator L (first actuator) and the provisional expansion/contraction amount δ _RC of actuator C (second actuator) in step S2 is performed by the first actuator provisional expansion/contraction amount determination block 3C and the second actuator provisional expansion/contraction amount determination block 3D, respectively (provisional expansion/contraction amount calculation step).
Then, proceed to step S3.

9, the maximum provisional extension amount and the minimum provisional contraction amount are determined by the maximum provisional extension amount/minimum provisional contraction amount determination block 3E from the calculation results of the provisional expansion amount δ _RL of actuator L (first actuator) and the provisional expansion amount δ _RC of actuator C (second actuator) in step S2, and the provisional expansion amount (=0 mm) of the reference actuator R. Then, the process proceeds to step S4.
In step S4, the temporary expansion/contraction amount correction value determination block 3F determines an apportionment correction value F, which is a correction value for the temporary expansion/contraction amount, based on the maximum temporary expansion amount and the minimum temporary contraction amount determined in step S3 (correction value calculation step).
As described above, the correction value F is calculated by the following formula: Then, the process proceeds to step S5.
Correction value F={(maximum provisional expansion amount)+(minimum provisional contraction amount)}/2

In step S5, the actuator R, L, C expansion amount determination block 3G corrects the calculation result of the provisional expansion amount δ _RL of actuator L (first actuator) in step S2, the calculation result of the provisional expansion amount δ _RC of actuator C (second actuator), and the provisional expansion amount 0 of actuator R based on the provisional expansion amount correction value (distribution correction value F) determined in step S4, and determines the actual expansion amount of each actuator R, L, C (L, C, R) (actual expansion amount calculation step). The calculation formula for the actual expansion amount is as shown in the explanation of the actuator R, L, C expansion amount determination block 3G in FIG. 8.
Once the actual amounts of expansion and contraction of the actuators R, L, and C have been determined in step S5, the actuators R, L, and C are operated to control the control target plate 1 so as to support it horizontally, as shown in FIG.
After the process of step S5, it is possible to execute a minimum stroke correction control (FIG. 11) which will be described later.

In Fig. 10, which shows the process following Fig. 9, in step S11, the extension or contraction of the actuator L is hydraulically controlled (e.g., hydraulically controlled) based on the actual extension or contraction amount of the actuator L determined in step S5 of Fig. 9. As described above in relation to Fig. 8, based on the tip positions of the actuators R, L, and C determined in the actuator selection position specification block 3A, the control unit 3 can determine whether the extension or contraction amount of each of the actuators R, L, and C has reached a target value. Alternatively, based on the extension or contraction amount measured by the potentiometer 4 (Fig. 3) provided on each of the actuators R, L, and C, the control unit 3 can determine whether the extension or contraction amount of each of the actuators R, L, and C has reached a target value.
In the next step S12, it is determined whether the amount of expansion or contraction of the actuator L reaches the target value within a predetermined time (for example, 10 seconds). The predetermined time is measured by a timer (not shown).
In step S12, if the extension or contraction amount of actuator L reaches the target value within a predetermined time (e.g., 10 seconds) (step S12 is "Yes"), proceed to step S13; if the extension or contraction amount of actuator L does not reach the target value within the predetermined time (e.g., 10 seconds) (step S12 is "No"), proceed to step S14.
In step S14 (if the extension/contraction amount of the actuator L does not reach the target value within the specified time), it is determined that there is some kind of malfunction regarding the control of the actuator L, and an ERR lamp (error lamp) not shown in the figure on the operation panel 6 (Figure 8) is turned on.

On the other hand, in step S13 (if the expansion/contraction amount of actuator L reaches the target value within the predetermined time), actuator R is hydraulically controlled based on the actual expansion/contraction amount of actuator R determined in step S5 of Fig. 9. Then, the process proceeds to step S15.
In step S15, it is determined whether the amount of expansion or contraction of the actuator R reaches the target value within a predetermined time (for example, 10 seconds).
In step S15, if the extension or contraction amount of actuator R reaches the target value within the specified time (step S15 is "Yes"), proceed to step S16; if not (step S15 is "No"), proceed to step S14.
In step S14 (when the extension or contraction amount of the actuator R does not reach the target value within the predetermined time), an ERR lamp (error lamp) (not shown) on the operation panel 6 (FIG. 8) is turned on.

In step S16 (if the extension or contraction amount of actuator R reaches the target value within the predetermined time), actuator C is hydraulically controlled based on the actual extension or contraction amount of actuator C determined in step S5 of Fig. 9. Then, the process proceeds to step S17.
In the next step S17, it is determined whether the amount of expansion or contraction of the actuator C reaches the target value within a predetermined time (for example, 10 seconds).
In step S17, if the amount of expansion or contraction of the actuator C reaches the target value within a predetermined time (for example, 10 seconds) (step S17 is "Yes"), the horizontal maintenance control is terminated.
On the other hand, if the extension or contraction amount of actuator C does not reach the target value within a predetermined time (e.g., 10 seconds) (step S17 is "No"), the process proceeds to step S14. In step S14 (if the extension or contraction amount of actuator C does not reach the target value within the predetermined time), an ERR lamp (error lamp) (not shown) on the operation panel 6 (FIG. 8) is turned on.
After the process of step S17, it is possible to execute repeated movement control of the control target plate (FIG. 12) which will be described later.
Here, the order of the actuators for controlling the expansion/contraction amounts is not limited to the order of actuator L, actuator R, and actuator C. It is possible to control the expansion/contraction amounts of the actuators in an order different from that shown in FIG.

The minimum stroke correction control will be described with reference to FIG.
For any of the actuators R, L, or C, if the amount of extension or contraction required to make the controlled plate 1 horizontal is less than a predetermined value δ (e.g., 5 mm), the amount of extension or contraction (stroke) becomes too small (too short) and actuator control becomes difficult.
In the illustrated embodiment, in order to avoid such difficult actuator control, a type of correction is performed in which the extension or contraction amount of actuators R, L, and C is increased or decreased by a predetermined value δ, on the condition that the actuator extension or contraction amount does not exceed 1/2 of the total actuator stroke (60 mm, since the total actuator stroke is 120 mm in the case of Figures 4 to 7). Here, since the actuator contraction is "negative," if the absolute value of the actuator contraction amount increases by δ mm, the stroke will decrease by δ mm. This type of control is sometimes referred to in this specification as "minimum stroke correction control."

The minimum stroke correction control in Fig. 11 is executed by the minimum stroke correction block 3H (Fig. 8) immediately after the (actual) expansion/contraction amounts of the actuators R, L, C have been determined in, for example, step S5 in Fig. 9. At that time, the correction amounts (calculation results) determined by the minimum stroke correction block 3H are transmitted to the expansion/contraction amount determination block 3G for the actuators R, L, C, and are reflected in the expansion/contraction amounts of the actuators R, L, C.
In FIG. 11, in step S21, it is determined whether the amount of expansion or contraction of any of the actuators R, L, C determined in step S5 in FIG. 9 is equal to or less than a predetermined value δ (for example, 5 mm).
If it is determined in step S21 that the amount of expansion or contraction of any one of the actuators R, L, C is equal to or less than a predetermined value δ (for example, 5 mm) (step S21 is " Yes "), the process proceeds to step S22.
On the other hand, if the amount of extension or contraction of any of the actuators R, L, C is greater than the predetermined value δ (e.g., 5 mm) (step S21 is "No"), the process proceeds to step S11 in FIG. 10, and actuator expansion/contraction control is performed based on the actual amount of extension or contraction of each actuator R, L, C determined in step S5 in FIG. 9.

11, in step S22 (when the extension or contraction amount of any of actuators R, L, C is equal to or less than a predetermined value δ), it is determined whether the value obtained by adding the predetermined value δ to the extension amount of actuators R, L, C determined in step S5 of FIG. 9 does not exceed 1/2 of the total stroke of the actuators (60 mm in the illustrated embodiment) and whether the value obtained by subtracting the predetermined value δ (for example, 5 mm) from the contraction amount of actuators R, L, C determined in step S5 of FIG. 9 is less than 1/2 of the total stroke of the actuators (for example, −60 mm).
In step S22, if the value obtained by adding a predetermined value δ to the extension amounts of actuators R, L, C determined in step S5 of FIG. 9 does not exceed half of the total stroke of the actuators, and if the value obtained by subtracting the predetermined value δ from the contraction amounts of actuators R, L, C determined in step S5 of FIG. 9 does not fall below half the total stroke of the actuators (−60 mm) (step S22 is “Yes”), proceed to step S23.
On the other hand, if the result of the judgment in step S22 is that the value obtained by adding the predetermined value δ to the extension amount of the actuators R, L, and C determined in step S5 of Fig. 9 is equal to or greater than ½ (60 mm) of the total stroke of the actuators, or the value obtained by subtracting the predetermined value δ from the contraction amount of the actuators R, L, and C determined in step S5 of Fig. 9 is equal to or less than ½ (−60 mm) of the total stroke of the actuators (step S22 is "No"), the process proceeds to step S24. As explained in Figs. 4 to 7, the extension of the actuators is a "positive" value and the contraction of the actuators is a "negative" value, so that subtracting the predetermined value δ from the contraction amount of the actuators increases the absolute value. In other words, if the absolute value of the value obtained by subtracting the predetermined value δ from the contraction amount is greater than the absolute value of ½ (−60 mm) of the total stroke, the process proceeds to step S24.

In step S23 (when the extension does not exceed 1/2 of the total stroke, and the contraction does not fall below 1/2 of the total stroke), the extension amounts of all actuators R, L, C are corrected to a value obtained by adding the predetermined value δ (e.g., 5 mm) to the extension amount determined in step S5 of Fig. 9. Alternatively, the contraction amount is corrected to a value obtained by subtracting the predetermined value δ (e.g., 5 mm) from the contraction amount determined in step S5 of Fig. 9. By increasing the absolute value of the extension or contraction by the predetermined amount δ, the extension or contraction amount also increases, thereby mitigating the difficulty of extending or contracting by a small distance.
In step S24 (when the extension is more than 1/2 of the total stroke, and when the contraction is less than 1/2 of the total stroke), the extension or contraction amount of actuators R, L, C is not corrected but the numerical value determined in step S5 in Fig. 9 is used as is. Extension or contraction whose absolute value is more than 1/2 of the total stroke makes the extension or contraction control of the actuators unstable, so such extension or contraction control of the actuators is avoided.
When the minimum stroke correction control of FIG. 11 is completed, the process proceeds to step S11 of FIG. 10, where the control of each of the actuators R, L, and C continues.

Next, the repeat movement control will be described with reference to FIG.
When an actuator that is expanding or contracting stops, it may expand more than the target amount or contract more than the target amount due to so-called "overshoot." In the illustrated embodiment, since three actuators R, L, and C are each expanded or contracted, there is a risk of an error of about 1 mm occurring due to overshoot.
In order to eliminate errors due to overshoot, in the illustrated embodiment, the actuators R, L, and C that are extended or contracted by the horizontal maintenance control are extended or contracted simultaneously in the same direction by the same distance σ (for example, 5 mm) once or multiple times in order to reduce errors due to overshoot by moving the three actuators simultaneously in the same direction by the same distance σ.
The term "repeated movement control" is used in this specification to mean a control for reducing the error due to overshoot by simultaneously extending or contracting the actuators (e.g., R, L, C) that have been extended or contracted by the horizontal maintenance control in the same direction by the same distance σ. In addition, the term "repeated movement control" also includes a case where the actuators are extended or contracted only once.

The repeated movement control is executed by the control target plate repeated movement block 3I (FIG. 8) immediately after, for example, step S17 in FIG. 10 is judged to be "Yes." At that time, the control content determined by the control target plate repeated movement block 3I is transmitted to the expansion/contraction amount determination block 3G of the actuators R, L, and C, and is reflected in the expansion/contraction amount control of the actuators R, L, and C.
12, in step S31, it is determined whether or not a command to execute "repeated movement control" has been input. The command is issued, for example, by an operator pressing and holding the horizontal AUTO switch 5 (FIG. 8) on the operation panel.
If a command to execute "repeated movement control" is input (step S31 is " Yes "), proceed to step S32; if a command to execute "repeated movement control" is not input (step S31 is "No"), repeated movement control is not performed.

In step S32 (when an execution command for "repeated movement control" is input), the number of times t for "repeated movement" is set to "t = 1." Then, the process proceeds to step S33.
In step S33, the actuators R, L, and C that have expanded or contracted to horizontally support the controlled plate 1 are moved once simultaneously in the same direction by the same distance σ (for example, 5 mm). At this time, the actuators R, L, and C are moved, so the horizontal state of the controlled plate 1 is maintained. Even if an overshoot occurs, the actuators R, L, and C move simultaneously in the same direction by the same distance σ, so that the errors of the actuators R, L, and C due to the overshoot are approximately the same, and the error between the actuators becomes extremely small.
Then, the process proceeds to step S34. In step S34, the number of "repeated movements" is set to
Set "t=t+1" and proceed to step S35. Note that if only one expansion or contraction is to be performed, steps S34 to S36 are not executed.

In step S35, it is determined whether the number of times t of "repeated movements" has reached a predetermined number (for example, two).
As a result of the determination in step S35, when the number of times t of "repeated movements" has reached a predetermined number of times (for example, two times) (step S35 is "Yes"), the repeated movement control ends.
On the other hand, if the number of times t of "repeated movements" does not reach the predetermined number of times (for example, twice) (step S35 is "No"), the process proceeds to step S36.
In step S36, the direction of movement (extension or contraction) of each of the actuators R, L, and C in step S33 is set so that the direction of movement is opposite to that in the immediately preceding control cycle. Then, the process returns to step S33, and each of the actuators R, L, and C is moved (extended or contracted) in the opposite direction to that in the immediately preceding control cycle.
The control loop of steps S33 to S36 is repeated until the number of times t of "repeated movements" reaches a predetermined number (for example, two times).
As described above, the number t of "repeated movements" may be only one.

The neutral position maintaining control will be described with reference to FIG.
Here, the neutral position maintenance control is a control for maintaining the actuators R, L, and C in a neutral position, for example, when a construction machine 30 (FIG. 1) equipped with a balance arm 20 (FIG. 1) is moved to a storage location after work using the construction machine 30 is completed. By maintaining the actuator extension amount in a neutral position, the actuators R, L, and C and the controlled plate 1 are not adversely affected even if vibrations caused by uneven ground occur, and there is no risk of distortion of the balance arm 20. As described above, the neutral position means a state in which the actuators R, L, and C are extended by 1/2 (e.g., 60 mm) of the maximum extension amount (total stroke: e.g., 120 mm) of the actuators R, L, and C.

The neutral position maintaining control is executed by a neutral position maintaining block 3J. At this time, a neutral position control signal from the neutral position maintaining block 3J is transmitted to an expansion/contraction amount determination block 3G for the actuators R, L, and C, and the expansion/contraction amounts are determined so that the actuators R, L, and C are in the neutral position.
13, in step S41, it is determined whether or not work is being performed by the balance arm 20. This determination is made, for example, by an operator, and if work is not being performed by the balance arm 20 (if work has ended), the operator operates the operation panel 6 (FIG. 8) to transmit a message indicating that work is not being performed by the balance arm 20.
In step S41, if work is being performed by the balance arm 20 (step S41 is "Yes"), proceed to step S42; if work is not being performed by the balance arm 20 (for example, if it has finished) (step S41 is "No"), proceed to step S43.

In step S42 (when work is being performed by the balance arm 20), horizontal maintenance control (the control in Figs. 9 to 12) is executed (continued) (a loop in which step S41 is Yes).
In step S43 (when no work is being performed by the balance arm 20), it is determined whether or not the actuators R, L, and C are each in a neutral position. The determination in step S43 as to whether or not they are in the neutral position can be made based on the measurement result from the potentiometer 4 transmitted via the signal transmission line SL23 (see FIG. 8). Alternatively, although not shown, it is possible to determine whether or not they are in the neutral position by identifying the tip position of each of the actuators R, L, and C in the actuator tip position identifying block 3A (see FIG. 8).
In step S43, if the actuators R, L, and C are each in a neutral position (step S43 is "Yes"), proceed to step S44, and if some or all of the actuators R, L, and C are not in a neutral position (step S43 is "No"), proceed to step S45.

In step S44 (when the actuators R, L, C are in the neutral positions), the actuators R, L, C are maintained in the neutral positions. That is, the actuators R, L, C are controlled so as to maintain the current neutral positions.
In step S45 (when some or all of the actuators R, L, C are not in the neutral position), the actuators R, L, C that are not in the neutral position are controlled to expand and contract so that all of the actuators R, L, C are brought to the neutral position.

According to the embodiment shown in the figures, the level maintenance device 10 is mounted on the construction machine 30 in order to keep the base 21 of the balance arm 20 fixed horizontally. Even when used on a site with so-called "bad footing" or a site with significant unevenness, the balance arm 20 can reliably function and can easily perform tasks such as suspending heavy loads.
The control unit 3 fixes one of the actuators R, L, C (for example, actuator R) in a neutral position, calculates virtual amounts of extension or contraction of the other two actuators L, C based on the Y-axis distance L _Y (FIG. 2) between actuators R and L, the X-axis distance L _X (FIG. 2) between actuators R and C, the X-axis tilt angle θ _X (FIG. 2), and the Y-axis tilt angle θ _Y (FIG. 2) so that the controlled plate 1 is horizontal in this state, calculates an allocation correction value F based on the calculated virtual amounts of extension or contraction, and calculates the actual amounts of extension or contraction of the actuators R, L, C from the virtual amounts of extension or contraction and the allocation correction value F. Therefore, there is no need to execute complicated control, and the base 21 of the balance arm 20 and the controlled plate 1 to which it is fixed can be supported horizontally without applying a large load to the control unit 3.
Furthermore, since the actual extension or contraction amounts of the actuators R, L, C are calculated using the allocation correction value F, a margin for the extension or contraction of the actuators R, L, C can be secured and unrealizable control that exceeds the maximum stroke (extension or contraction amount) of the actuators R, L, C can be prevented.

In the illustrated embodiment, the control unit 3 (control device) is provided with a minimum stroke correction block 3H, so that it is possible to avoid a situation in which the actual extension or contraction amount of the actuator mechanisms R, L, C is too small, making it difficult to control the extension or contraction.
In addition, in the illustrated embodiment, the control unit 3 (control device) is equipped with a controlled plate repeated movement block 3I, and the actuators R, L, C, which are extended or contracted to support the controlled plate 1 horizontally, are extended or contracted simultaneously in the same direction by the same distance σ (for example, 5 mm) once or multiple times, thereby making it possible to minimize the relative error due to overshoot of each actuator R, L, C and prevent the controlled plate 1 from tilting.
In addition, in the illustrated embodiment, when the balance arm 20 is not being used (for example, when work using the construction machine 30 equipped with the balance arm 20 has been completed and the construction machine 30 is moved to a storage location), all of the actuators R, L, C are kept in neutral positions, so that even if vibrations caused by unevenness in the ground act, they are prevented from adversely affecting the actuators R, L, C and the controlled plate 1, and there is no risk of distortion of the balance arm 20 (see FIG. 13).

It should be noted that the illustrated embodiment is merely an example and is not intended to limit the technical scope of the present invention.
For example, in the illustrated embodiment, a balance arm is exemplified as a working device of the construction machine 30, but the present invention can be applied to maintaining the horizontality of a lifting machine or other working device other than a balance arm.

1: Control target plate 2: Measurement device 2A: X-axis tilt angle sensor 2B: Y-axis tilt angle sensor 3: Control unit (control device)
10: Horizontal maintenance device 20: Balance arm 21: Base of balance arm 30: Construction machine R, L, C: Actuator F: Correction value (distribution correction value)
δ: Predetermined value of contraction amount (minimum stroke correction control)
σ・・・Same distance that expands and contracts (repeated movement control)

Claims (5)

A horizontal maintenance device for keeping the working equipment of a construction machine horizontally and fixed,
a control target plate which is a plate-like member having a substantially triangular shape and to which a working device of a construction machine is fixed;
An actuator is disposed at a position corresponding to the apex of a triangle on the control target plate;
A measuring device that measures the inclination of the control target plate;
a control device that determines an amount of expansion or contraction of the actuator based on a measurement result of the measuring device;
The control device includes:
A function of calculating the virtual expansion or contraction amount of the other two actuators so that the control target plate becomes horizontal with one of the actuators fixed in a neutral position;
a function of calculating a correction value based on the calculated virtual extension or contraction amount so as to reduce the extension or contraction amount of two actuators other than the actuator fixed at the neutral position to less than the virtual extension or contraction amount , and calculating the extension or contraction amount of each of the actuator fixed at the neutral position and the other two actuators from the virtual extension or contraction amount and the correction value,
The level maintenance device is characterized in that the control device has a function of simultaneously extending or contracting the actuators that have been extended or contracted by level maintenance control, in the same direction, by the same distance, once or multiple times . A horizontal maintenance device for keeping the working equipment of a construction machine horizontally and fixed,
a control target plate which is a plate-like member having a substantially triangular shape and to which a working device of a construction machine is fixed;
An actuator is disposed at a position corresponding to the apex of a triangle on the control target plate;
A measuring device that measures the inclination of the control target plate;
a control device that determines an amount of expansion or contraction of the actuator based on a measurement result of the measuring device;
The control device includes:
A function of calculating the virtual expansion or contraction amount of the other two actuators so that the control target plate becomes horizontal with one of the actuators fixed in a neutral position;
a function of calculating a correction value based on the calculated virtual extension or contraction amount so as to reduce the extension or contraction amount of two actuators other than the actuator fixed at the neutral position to less than the virtual extension or contraction amount, and calculating the extension or contraction amount of each of the actuator fixed at the neutral position and the other two actuators from the virtual extension or contraction amount and the correction value,
A horizontal maintenance device characterized in that the control device has a function of keeping all of the actuators in a neutral position when the work implement of the construction machine is not in use. 3. The level maintenance device according to claim 1, which is mounted on a construction machine. 4. The horizontal maintenance device according to claim 1 , wherein the control device has a function of setting the correction value to a value that is half the sum of the maximum virtual expansion amount and the minimum virtual contraction amount. A horizontal maintenance device according to any one of claims 1 to 4 , wherein the control device has a function of increasing or decreasing the amount of extension or contraction in all actuators by a predetermined value when the actual amount of extension or contraction of any actuator is equal to or less than a predetermined value.

Images