JP2021147131A - Prediction system of tip position of boom and prediction method of tip position of boom - Google Patents

Abstract

To provide a prediction system of a tip position of a boom capable of predicting the tip position of the boom.SOLUTION: A prediction system S of a tip position of a boom includes a boom 14 constituted to freely rise and fall, a derricking cylinder 62 for derricking the boom 14, a pressure measurement instrument 21 for measuring the pressure of the derricking cylinder 62, a winch 13 for winding/unwinding a suspended cargo through a wire 16, wire length measurement instruments (22, 23) for measuring the length of the wire 16, and a controller 40 serving as a control unit for controlling the derricking cylinder 62 and the winch 13 such that the controller 40 predicts a tip position of the boom 14 based on the pressure of the derricking cylinder 62 measured by the pressure measurement instrument 21 and the length of the wire 16 measured by the length measurement instruments (22, 23).SELECTED DRAWING: Figure 3

Description

The present invention relates to a boom tip position prediction system and a boom tip position prediction method applicable to a load device including a mobile crane.

Conventionally, in a crane equipped with a boom, when lifting a suspended load from the ground, that is, when cutting the suspended load, the bending caused by the boom increases the working radius, so that the suspended load swings in the horizontal direction. "Load runout" is a problem (see Fig. 1).

For the purpose of preventing load runout during ground cutting, for example, the vertical ground cutting control device described in Patent Document 1 detects the engine speed by an engine speed sensor and raises and lowers the boom. It is configured to be corrected to a value according to the engine speed. With such a configuration, it is said that accurate ground cutting control can be performed in consideration of changes in engine speed.

Japanese Unexamined Patent Publication No. 8-188379

However, the conventional ground cutting control device including Patent Document 1 does not have a means for detecting whether or not the tip position of the boom is located directly above the suspended load. Therefore, there is a risk that the tip of the boom will run out of the ground with the tip position deviated from directly above the suspended load.

Therefore, an object of the present invention is to provide a boom tip position prediction system capable of predicting the boom tip position, and a boom tip position prediction method.

In order to achieve the above object, the boom tip position prediction system of the present invention includes a boom configured to be undulating, an undulating cylinder for undulating the boom, and a pressure measuring device for measuring the pressure of the undulating cylinder. , A winch for hoisting / unwinding a suspended load via a wire, a wire length measuring instrument for measuring the length of the wire, a control unit for controlling the undulating cylinder and the winch, and the pressure measuring instrument. A control unit that predicts the tip position of the boom based on the pressure of the undulating cylinder measured by the undulating cylinder and the length of the wire measured by the length measuring instrument. ing.

Further, the method of predicting the tip position of the boom of the present invention is a method of predicting the tip position of the boom, which includes a step of undulating and moving the boom upward and / or downward, and a step of measuring the pressure of the undulating cylinder. , A step of measuring the length of the wire, and a step of predicting the tip position of the boom based on the pressure of the undulating cylinder and the length of the wire.

As described above, the boom tip position prediction system of the present invention includes the boom, the undulating cylinder, the pressure measuring instrument, the winch, the wire length measuring instrument, the undulating cylinder pressure, and the wire length. Based on this, it includes a control unit that is designed to predict the tip position of the boom. According to such a configuration, the tip position of the boom can be predicted by a simple configuration using existing sensors.

Further, the method of predicting the tip position of the boom of the present invention is a method of predicting the tip position of the boom, which includes a step of undulating and moving the boom upward and / or downward, and a step of measuring the pressure of the undulating cylinder. It includes a step of measuring the length of the wire and a step of predicting the tip position of the boom based on the pressure of the undulating cylinder and the length of the wire. According to such a configuration, the tip position of the boom can be predicted by a simple configuration using existing sensors.

It is explanatory drawing explaining the load runout of a suspended load. It is a side view of a mobile crane. It is a block diagram of the prediction system of the tip position of a boom. It is explanatory drawing explaining the calculation method of the virtual friction force based on the tension (the function of the pressure of the undulating cylinder) and the length of a wire. It is a flowchart of the prediction system of the tip position of a boom. It is a graph explaining the operation of the prediction system of the tip position of a boom.

Hereinafter, examples according to the present invention will be described with reference to the drawings. However, the components described in the following examples are examples, and the technical scope of the present invention is not limited to them.

In this embodiment, examples of the mobile crane include a rough terrain crane, an all terrain crane, and a truck crane. Hereinafter, a rough terrain crane will be described as an example of the work vehicle according to the present embodiment, but the control device according to the present invention can also be applied to other mobile cranes. Furthermore, the present invention can be applied not only to mobile cranes but also to weighting devices using other wires.

(Structure of mobile crane)
First, the configuration of the mobile crane will be described with reference to the side view of FIG. As shown in FIG. 2, the rough terrain crane 1 of the present embodiment has a vehicle body 10 which is a main body portion of a vehicle having a traveling function, outriggers 11 provided at four corners of the vehicle body 10, ... It includes a swivel base 12 mounted so as to be able to swivel horizontally, and a boom 14 mounted behind the swivel base 12.

The outrigger 11 can slide out / slide outward from the vehicle body 10 in the width direction by expanding / contracting the slide cylinder, and can extend / jack retract in the vertical direction from the vehicle body 10 by expanding / contracting the jack cylinder. Is.

The swivel base 12 has a pinion gear to which the power of the swivel motor 61 is transmitted, and the pinion gear meshes with a circular gear provided on the vehicle body 10 to rotate around a swivel shaft. The swivel base 12 has a cockpit 18 arranged on the right front side and a counterweight 19 arranged on the rear side.

Further, behind the swivel base 12, a winch 13 for hoisting / lowering the wire 16 is arranged. By rotating the winch motor 64 in the forward direction / the reverse direction, the winch 13 rotates in two directions, a winding direction (winding direction) and a winding direction (feeding direction).

The boom 14 is nested by a base end boom 141, an intermediate boom 142 (s) and a tip boom 143, and can be expanded and contracted by an telescopic cylinder 63 arranged inside. A sheave is arranged on the state-of-the-art boom head 144 of the tip boom 143, and a wire 16 is hung around the sheave to hang a hook 17.

The base portion of the base end boom 141 is rotatably attached to a support shaft installed on the swivel base 12, and can be undulated up and down with the support shaft as the center of rotation. An undulating cylinder 62 is bridged between the swivel base 12 and the lower surface of the base end boom 141, and the entire boom 14 can be undulated by expanding and contracting the undulating cylinder 62. ..

(Control system configuration)
Next, the configuration of the control system of the boom tip position prediction system S of this embodiment will be described with reference to the block diagram of FIG. The boom tip position prediction system S is configured around a controller 40 as a control unit. The controller 40 is a general-purpose microcomputer having an input port, an output port, an arithmetic unit, and the like. The controller 40 receives an operation signal from the operation levers 51 to 54 (swivel lever 51, undulation lever 52, telescopic lever 53, winch lever 54), and receives actuators 61 to 64 (swivel motor 61, swivel motor 61, via a control valve (not shown)). The undulating cylinder 62, the telescopic cylinder 63, and the winch motor 64) are controlled.

Further, the controller 40 of the present embodiment includes a start switch 20 for starting the prediction of the tip position of the boom, a pressure measuring instrument 21 for measuring the pressure of the undulating cylinder 62, and a wire length for measuring the wire length. The rotation speed measuring instrument 22 and the attitude measuring instrument 23 as measuring instruments are connected as an input system.

The start switch 20 is an input device that instructs the start (or stop) of "predictive control of the tip position of the boom 14", and can be configured to be added to the safety device of the rough terrain crane 1, for example. The start switch 20 is preferably arranged in the cockpit 18. As the start switch 20, a ground cutting start switch (not shown) for starting the ground cutting control can also be used. That is, it is also possible to carry out the present invention at the initial stage of ground cutting control.

The pressure measuring instrument 21 is a measuring device for measuring the load acting on the boom 14, and is a pressure gauge attached to the undulating cylinder 62 to measure the oil pressure of the hydraulic oil acting inside the undulating cylinder 62. The pressure signal measured by the pressure measuring instrument 21 is transmitted to the controller 40. Then, as shown in FIG. 4, which will be described later, in the controller 40, the term of the tension on the left side of the equation (3) is calculated based on the pressure measured by the pressure measuring instrument 21.

The wire length measuring instruments (22, 23) are composed of a rotation speed measuring instrument 22 for measuring the rotation speed of the winch 13 and a posture measuring instrument 23 for measuring the posture of the boom 14. Then, as shown in FIG. 4, which will be described later, in the controller 40, the rotation speed (rotation speed) γ measured by the rotation speed measuring instrument 22 and the undulation angle θ and the undulation angular velocity θ (dots) measured by the attitude measuring instrument 23. ) And, and the terms based on the changes in the wire lengths of the first and second terms on the right side of the equation (3) are calculated.

The rotation speed measuring instrument 22 is installed near the rotation axis of the winch (drum) 13 and measures the rotation speed (rotation speed) of the winch (drum) 13. The rotation speed (rotation speed) measured by the rotation speed measuring instrument 22 is transmitted to the controller 40 and used for calculating the winch winding speed and the wire length.

The posture measuring instrument 23 is a measuring device for measuring the posture of the boom 14, and includes an undulation angle meter 23a for measuring the undulation angle of the boom 14 and an undulation angular velocity meter 23b for measuring the undulation angular velocity. Specifically, a potentiometer can be used as the undulation angle meter 23a. Further, as the undulation angular velocity meter 23b, a stroke sensor attached to the undulation cylinder 15 can be used. The undulation angle signal measured by the undulation angle meter 23a and the undulation angular velocity signal measured by the undulation angular velocity meter 23b are transmitted to the controller 40.

The controller 40 is a control unit that controls the operation of the boom 14 and the winch 13, and is a preparatory step for hoisting the winch 13 and grounding the suspended load when the start switch 20 is turned on, or as a ground cutting operation. As an initial step, the tip position of the boom 14 is predicted. The controller 40 predicts the tip position of the boom based on the pressure (p) of the undulating cylinder 62 measured by the pressure measuring instrument 21 and the wire length measured by the length measuring instruments (22, 23). It is made to do.

Specifically, as shown in FIG. 4, the controller 40 has a moving function unit 40a for moving the boom 14 upward and / or downward as a functional unit, and the tip position of the boom 14 is a suspended load. It has a determination function unit 40b for determining whether or not it is located directly above.

First, the moving function unit 40a starts winding the wire 16 by the winch 13, and sets a state in which the pressure of the undulating cylinder 62 becomes equal to or higher than a predetermined threshold value as an initial state. Then, the moving function unit 40a is adapted to undulate and move the boom 14 upward and / or downward with a predetermined angular width based on the initial state.

Based on the relationship shown in FIG. 4, the determination function unit 40b changes the pressure of the undulating cylinder 62 and the length of the wire 16 with time when the boom 14 is undulated and moved upward and / or downward. The tip position of the boom 14 is predicted based on the above. More specifically, the tip position of the boom 14 is suspended at the time when the virtual frictional force indirectly calculated based on the pressure of the undulating cylinder 62 and the length of the wire 16 changes with time to the minimum. It is designed to determine that it is located directly above the load.

That is, using the equation (4) of FIG. 4, the minimum value is searched for based on the change over time of ΔFsinφ, and the tip position of the boom 14 is located directly above the suspended load in the state where the minimum value is reached. It is determined that there is. In FIG. 4, T represents the tension of the wire, γ represents the winch rotation speed, θ represents the undulation angle, θ (dot) represents the undulation angle velocity, L represents the boom length, and k and k ′ represent the elongation coefficient of the wire. ..

(flowchart)
Next, the flow of predictive control of the tip position of the boom of this embodiment will be described with reference to the flowchart of FIG.

First, when the operator presses the start switch 20, predictive control of the tip position of the boom is started (step S1). Then, the winding of the winch 13 is automatically started (step S2). That is, the controller 40 commands the winch motor 64 to wind up. Next, at the same time as winding the winch 13, the pressure of the undulating cylinder 62 is measured by the pressure measuring instrument 21 (step S3). The measured pressure is transmitted to the controller 40.

Then, the controller 40 calculates the tension based on the transmitted pressure of the undulating cylinder 62, and determines whether or not the tension is equal to or higher than a predetermined tension (step S4). Then, if the tension is equal to or higher than the predetermined tension, the winch 13 is stopped (step S5). If the tension is less than the predetermined tension, the process returns to step S2 to continue winding the winch 13. This state is the initial state. By the control up to this point, a predetermined tension is generated in the wire 16.

Next, the moving function unit 40a of the controller 40 raises / lowers the boom 14 within a predetermined angle range with reference to the initial state (step S6). That is, the moving function unit 40a commands and executes the undulating cylinder 62 to undulate and undulate little by little with a predetermined angle width based on the initial state, so that the tip position of the boom 14 is positioned directly above the suspended load. Search for the state to do.

Then, at the same time as raising / lowering the undulations of the boom 14, the pressure of the undulation cylinder 62 is measured by the pressure measuring instrument 21 (step S7). The measured pressure is transmitted to the controller 40. Next, the determination function unit 40b of the controller 40 calculates the (virtual) frictional force based on the equation (4) of FIG. 4 (S8). That is, the (virtual) frictional force is indirectly calculated based on the time-dependent changes in the pressure of the undulating cylinder 62 and the length of the wire 16.

Next, the determination function unit 40b determines whether or not the calculated frictional force is the minimum value (step S9). Then, if the frictional force is the minimum value (YES in step S9), the undulation angle at this time is stored (step S10). On the other hand, if the frictional force is not the minimum value (NO in step S9), the process returns to step S6. Then, by repeating steps S6 to S10 in a predetermined angle range, the undulation angle showing the minimum value of the frictional force in the predetermined angle range is searched and determined.

Finally, by raising or lowering the boom 14 to the position where the frictional force becomes the minimum value, the tip position of the boom 14 is positioned directly above the suspended load (step S11), and the process is completed. ..

(Judgment of tip position)
Next, the concept of the method for determining the tip position of the boom of this embodiment will be described with reference to the graph of FIG. As described above, in the present embodiment, the determination function unit 40b of the controller 40 has the minimum virtual frictional force indirectly calculated based on the change over time of the pressure of the undulating cylinder 62 and the length of the wire 16. At that time, it is determined that the tip position of the boom 14 is located directly above the suspended load.

For example, when the tip position of the boom 14 is located directly above the suspended load, the tension T at the same time becomes relatively small and the ground is cut by that amount, as shown by the solid line in FIG. The time will be late. On the other hand, when the tip position of the boom 14 is located at a position deviated from directly above the suspended load, the tension T at the same time becomes relatively large as shown by the alternate long and short dash line in FIG. The time to cut the ground will be earlier.

(effect)
Next, the effects of the boom tip position prediction system S of this embodiment will be listed and described.

(1) As described above, the boom tip position prediction system S of the present embodiment measures the pressure of the boom 14 configured to be undulating, the undulating cylinder 62 for undulating the boom 14, and the undulating cylinder 62. A pressure measuring instrument 21 to be used, a winch 13 for hoisting / unwinding a suspended load via a wire 16, a wire length measuring instrument (22, 23) for measuring the length of the wire 16, and an undulating cylinder 62 and a winch 13. Based on the pressure of the undulating cylinder 62 measured by the pressure measuring instrument 21 and the length of the wire 16 measured by the length measuring instruments (22, 23). , A controller 40, which is designed to predict the tip position of the boom 14. According to such a configuration, the tip position of the boom can be predicted by a simple configuration using existing sensors.

That is, when the pressure measuring instrument 21 and the length measuring instrument (rotation speed measuring instrument 22 and posture measuring instrument 23) are mounted on the existing working machine, the tip position of the boom 14 is finely measured by using these measuring instruments. It is possible to efficiently carry out ground cutting work including adjustment. That is, in the ground cutting work, the suspended load can be lifted at high speed without swinging. Further, since the ground cutting determination is facilitated, the entire work time is shortened. In addition, since the number of parameters to be handled is small, the test adjustment man-hours can be shortened.

(2) Further, the wire length measuring instrument is preferably composed of a rotation speed measuring instrument 22 for measuring the rotation speed of the winch 13 and a posture measuring instrument 23 for measuring the posture of the boom 14. The posture measuring instrument 23 is preferably composed of an undulation angle meter 23a for measuring the undulation angle of the boom 14 and an undulation angular velocity meter 23b for measuring the undulation angular velocity.

(3) Further, the controller 40 undulates the boom 14 upward and / or downward, and the tip position of the boom 14 is based on the time-dependent change of the pressure of the undulating cylinder 62 and the length of the wire 16. Is supposed to be predicted. With this configuration, the tip position of the boom 14 can be predicted directly, easily, and accurately at the work site without performing complicated calculations in advance.

(4) Further, in the controller 40, when the boom 14 is undulated and moved upward and / or downward, the tip position of the boom 14 is suspended at the time when the indirectly calculated virtual friction force is minimized. It is preferable that it is determined that it is located directly above the load. With this configuration, it is possible to accurately predict that the tip position of the boom 14 will be located directly above the suspended load based on the measured value.

(5) Further, the controller 40 starts winding the wire 16 by the winch 13, sets the initial state when the pressure of the undulating cylinder 62 becomes equal to or higher than a predetermined threshold value, and sets the boom 14 based on this initial state. It is preferable that the undulations are moved upward and / or downward. With this configuration, it is possible to prevent the boom 14 from being unintentionally cut off when the boom 14 is undulated in the prediction control of the tip position.

(6) Further, the method of predicting the tip position of the boom of this embodiment includes a step of undulating and moving the boom 14 upward and / or downward, a step of measuring the pressure of the undulating cylinder 62, and a length of the wire 16. It includes a step of measuring the height and a step of predicting the tip position of the boom based on the pressure of the undulating cylinder 62 and the length of the wire 16. With such a configuration, the tip position of the boom can be predicted by a simple process using existing sensors.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes to the extent that the gist of the present invention is not deviated are described in the present invention. included.

For example, although not particularly described in the examples, the prediction system S of the tip position of the boom of the present invention is used regardless of whether the winch 13 is grounded using the main winch or the sub winch. Can be applied.

Further, in the embodiment, the boom 14 is raised / lowered to search for the position directly above the suspended load, but the present invention is not limited to this, and the boom 14 is additionally mounted on the boom head 144. It is also possible to attach a load cell to the sheave and measure the direction of the load (that is, the direction in which the wire 16 extends).

S: Boom tip position prediction system;
1: Rough terrain crane; 10: Body; 12: Swivel;
13: Winch; 14: Boom; 16: Wire; 17: Hook;
20: Start switch; 21: Pressure measuring instrument;
22: Rotation speed measuring instrument (part of wire length measuring instrument);
23: Posture measuring instrument (part of wire length measuring instrument);
40: Controller;
51: Swing lever; 52: Undulating lever;
53: Telescopic lever; 54: Winch lever;
61: Swing motor; 62: Undulating cylinder;
63: Telescopic cylinder; 64: Winch motor

Claims (6)

A boom that can be undulated and
The undulating cylinder that undulates the boom and
A pressure measuring instrument that measures the pressure of the undulating cylinder,
A winch that hoistes / unwinds a suspended load via a wire,
A wire length measuring instrument that measures the length of the wire,
A control unit that controls the undulating cylinder and the winch, based on the pressure of the undulating cylinder measured by the pressure measuring instrument and the length of the wire measured by the wire length measuring instrument. The control unit, which is designed to predict the tip position of the boom,
A boom tip position prediction system. The boom tip position according to claim 1, wherein the wire length measuring instrument comprises a rotation speed measuring instrument for measuring the rotation speed of the winch and a posture measuring instrument for measuring the posture of the boom. Prediction system. The control unit undulates the boom upward and / or downward, and predicts the tip position of the boom based on the time course of the pressure of the undulating cylinder and the length of the wire. The boom tip position prediction system according to claim 1 or 2. When the boom is undulated and moved upward and / or downward, the control unit sets the tip position of the boom to the true position of the suspended load at the time when the indirectly calculated virtual friction force becomes the minimum. The boom tip position prediction system according to claim 3, wherein the boom tip position is determined to be located above. The control unit starts winding the wire by the winch, sets the initial state when the pressure of the undulating cylinder becomes equal to or higher than a predetermined threshold value, and moves the boom upward and / or based on the initial state. Alternatively, the boom tip position prediction system according to claim 3 or 4, wherein the boom is undulated downward. It is a method of predicting the tip position of the boom.
Steps to undulate the boom upwards and / or downwards,
Steps to measure the pressure of the undulating cylinder and
Steps to measure the length of the wire and
A step of predicting the tip position of the boom based on the pressure of the undulating cylinder and the length of the wire, and
A method of predicting the tip position of the boom.

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