JP7435090B2 - Boom tip position prediction system - Google Patents

Description

The present invention relates to a boom tip position prediction system and a boom tip position prediction method that can be applied to lifting equipment including mobile cranes.

Conventionally, in a crane equipped with a boom, when lifting a suspended load from the ground, that is, when lifting the suspended load from the ground, the working radius increases due to the deflection that occurs in the boom, causing the suspended load to swing horizontally. "Load swing" has become a problem (see Figure 1).

For the purpose of preventing load swing during ground cutting, the vertical ground cutting control device described in Patent Document 1, for example, detects the engine rotation speed using an engine rotation speed sensor and controls the boom raising/raising operation. It is configured to correct the value according to the engine rotation speed. It is said that with such a configuration, it is possible to perform accurate ground-off control that takes into account changes in engine speed.

Japanese Patent Application Publication No. 8-188379

However, conventional ground cutting control devices including Patent Document 1 do not have a means for detecting whether the tip position of the boom is located directly above the suspended load. Therefore, there was a risk that the tip of the boom would deviate from directly above the suspended load and the load would swing.

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

In order to achieve the above object, the boom tip position prediction system of the present invention includes a boom configured to be able to be raised and lowered freely, a lifting cylinder that raises and lowers the boom, and a pressure measuring device that measures the pressure of the lifting cylinder. , a winch for hoisting/lowering a suspended load via a wire, a wire length measuring device for measuring the length of the wire, and a control unit for controlling the undulating cylinder and the winch, the pressure measuring device a control unit configured to predict the tip position of the boom based on the pressure of the undulation cylinder measured by the undulating cylinder and the length of the wire measured by the length measuring device. , the control unit moves the boom upward and/or downward, and predicts the tip position of the boom based on changes over time in the pressure of the undulation cylinder and the length of the wire. It is like that .

Further, the boom tip position prediction method of the present invention is a boom tip position prediction method, which includes a step of moving the boom up and down in an upward and/or downward direction, and a step of measuring the pressure of the hoisting cylinder. , measuring the length of the wire, and 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 can be used to predict the boom, the luffing cylinder, the pressure measuring device, the winch, the wire length measuring device, the pressure of the luffing cylinder, and the length of the wire. a controller configured to predict the boom tip position based on the boom tip position. According to such a configuration, the tip position of the boom can be predicted with a simple configuration using existing sensors.

Further, the boom tip position prediction method of the present invention is a boom tip position prediction method, which includes a step of moving the boom up and down in an upward and/or downward direction, and a step of measuring the pressure of the hoisting cylinder. , measuring the length of the wire, and predicting the boom tip position based on the pressure in the luffing cylinder and the length of the wire. According to such a configuration, the tip position of the boom can be predicted with a simple configuration using existing sensors.

It is an explanatory view explaining load swing of a hanging load. It is a side view of a mobile crane. FIG. 2 is a block diagram of a prediction system for the tip position of a boom. FIG. 3 is an explanatory diagram illustrating a method of calculating a virtual frictional force based on tension (a function of the pressure of the undulating cylinder) and the length of the 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 for the tip position of the boom.

Embodiments according to the present invention will be described below with reference to the drawings. However, the constituent elements described in the following examples are merely examples, and the technical scope of the present invention is not intended to be limited thereto.

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 is applicable not only to mobile cranes but also to lifting devices using other wires.

(Mobile crane configuration)
First, the configuration of the mobile crane will be described using the side view of FIG. 2. As shown in FIG. 2, the rough terrain crane 1 of this embodiment includes a car body 10 which is the main body part of a vehicle having a traveling function, outriggers 11 provided at the four corners of the car body 10, and It includes a swivel base 12 that is attached to be horizontally swivelable, and a boom 14 that is attached to the rear of the swivel base 12.

The outrigger 11 can be slid outward from the vehicle body 10 in the width direction and retracted by extending and contracting the slide cylinder, and can be extended and retracted in the vertical direction from the vehicle body 10 by extending and contracting the jack cylinder. It is.

The swivel base 12 has a pinion gear to which the power of the swivel motor 61 is transmitted, and this pinion gear meshes with a circular gear provided on the vehicle body 10 to rotate around the swivel shaft. The swivel base 12 has a pilot's seat 18 located at the front right and a counterweight 19 located at the rear.

Further, a winch 13 for hoisting/lowering the wire 16 is arranged behind the swivel base 12. The winch 13 is configured to rotate in two directions: a winding direction (rewinding direction) and a lowering direction (feeding direction) by rotating a winch motor 64 in a forward direction and a reverse direction.

The boom 14 is constructed in a telescopic manner by a proximal boom 141, one or more intermediate booms 142, and a distal boom 143, and can be extended and contracted by a telescoping cylinder 63 disposed inside. A sheave is arranged on the boom head 144 at the most distal end of the distal end boom 143, and a hook 17 is suspended from a wire 16 wrapped around the sheave.

The base of the proximal end boom 141 is rotatably attached to a support shaft installed on the swivel base 12, and can be raised and lowered about the support shaft as the center of rotation. A hoisting cylinder 62 is spanned between the swivel base 12 and the lower surface of the base end boom 141, and by extending and contracting the hoisting cylinder 62, the entire boom 14 can be hoisted. .

(Control system configuration)
Next, the configuration of the control system of the boom tip position prediction system S of this embodiment will be described using the block diagram of FIG. 3. The boom tip position prediction system S is mainly configured with a controller 40 as a control section. 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 operation signals from the operation levers 51 to 54 (swivel lever 51, undulating lever 52, telescopic lever 53, and winch lever 54), and controls the actuators 61 to 64 (swivel motor 61, It controls the undulating cylinder 62, the telescopic cylinder 63, and the winch motor 64).

Furthermore, the controller 40 of this embodiment includes a start switch 20 for starting prediction of the tip position of the boom, a pressure measuring device 21 for measuring the pressure of the luffing cylinder 62, and a wire length measuring device 21 for measuring the length of the wire. A rotation speed measuring device 22 and a posture measuring device 23 are connected as an input system.

The start switch 20 is an input device that instructs to start (or stop) "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 located in the cockpit 18. Note that the start switch 20 can also be used as a ground cut start switch (not shown) for starting the ground cut control. That is, it is also possible to implement the present invention at the initial stage of ground cutting control.

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

The wire length measuring device (22, 23) includes a rotational speed measuring device 22 that measures the rotational speed of the winch 13 and an attitude measuring device 23 that measures the attitude of the boom 14. As shown in FIG. 4, which will be described later, in the controller 40, the rotation speed (rotational speed) γ measured by the rotation speed measuring device 22, the heave angle θ and the heave angular velocity θ (dot ), the first and second terms on the right side of equation (3), which are based on changes in wire length, are calculated.

The rotation speed measuring device 22 is installed near the rotation axis of the winch (drum) 13 and measures the rotation speed (rotational speed) of the winch (drum) 13. The number of rotations (rotational speed) measured by the number of rotations measuring device 22 is transmitted to the controller 40 and used to calculate the winch hoisting speed and wire length.

The attitude measuring device 23 is a measuring device that measures the attitude of the boom 14, and includes a hoisting angle meter 23a that measures the hoisting angle of the boom 14, and a hoisting angular velocity meter 23b that measures the hoisting angular velocity. Specifically, a potentiometer can be used as the undulation angle meter 23a. Moreover, a stroke sensor attached to the undulation cylinder 15 can be used as the undulation angular velocity meter 23b. The heave angle signal measured by the heave angle meter 23a and the heave angular velocity signal measured by the heave 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 when the start switch 20 is turned on, the winch 13 is hoisted to perform a preparatory process for hoisting a suspended load, or as a preparatory step for ground cutting operation. As an initial step, the position of the tip 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 device 21 and the length of the wire measured by the length measuring devices (22, 23). It is made to be.

Specifically, as shown in FIG. 4, the controller 40 includes a moving function section 40a that moves the boom 14 upwardly and/or downwardly, and a moving function section 40a that moves the boom 14 upwardly and/or downwardly. It has a determination function section 40b that determines whether or not it is located directly above.

The moving function unit 40a first starts winding up the wire 16 with the winch 13, and sets a state in which the pressure of the undulation cylinder 62 exceeds a predetermined threshold value as an initial state. The movement function section 40a is configured to move the boom 14 upward and/or downward by a predetermined angular width based on the initial state.

Based on the relationship shown in FIG. 4, the determination function unit 40b determines the changes over time in the pressure of the undulating cylinder 62 and the length of the wire 16 when the boom 14 is moved upward and/or downward. Based on this, the tip position of the boom 14 is predicted. More specifically, the tip position of the boom 14 is suspended at the point in time when the virtual frictional force indirectly calculated based on the pressure of the luffing cylinder 62 and the change in the length of the wire 16 becomes the minimum. It is determined that the object is located directly above the load.

In other words, the minimum value is searched for based on the change in ΔFsinφ over time using equation (4) in FIG. It is determined that there is. In Figure 4, T is the wire tension, γ is the winch rotation speed, θ is the heave angle, θ (dot) is the heave angular speed, L is the boom length, and k and k' are the wire elongation coefficients, respectively. .

(flowchart)
Next, the flow of predictive control of the boom tip position of this embodiment will be explained using the flowchart of FIG.

First, when the operator presses the start switch 20, predictive control of the boom tip position is started (step S1). Then, winding up of the winch 13 is automatically started (step S2). That is, the controller 40 instructs the winch motor 64 to hoist. Next, at the same time as the winch 13 is hoisted, the pressure in the undulating cylinder 62 is measured by the pressure measuring device 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 the tension is equal to or higher than a predetermined tension (step S4). If the tension is greater than a 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 hoisting the winch 13. This state is set as the initial state. Through the control so far, a predetermined tension is generated in the wire 16.

Next, the movement function section 40a of the controller 40 raises/lowers the boom 14 within a predetermined angle range based on the initial state (step S6). That is, the movement function unit 40a commands and executes the raising and lowering of the luffing cylinder 62 little by little in a predetermined angular width based on the initial state, so that the tip of the boom 14 is positioned directly above the suspended load. Explore the state of

Simultaneously with the raising/lowering of the boom 14, the pressure in the raising/lowering cylinder 62 is measured by the pressure measuring device 21 (step S7). The measured pressure is transmitted to the controller 40. Next, the determination function unit 40b of the controller 40 calculates a (virtual) frictional force based on equation (4) in FIG. 4 (S8). That is, the (virtual) frictional force is indirectly calculated based on the pressure of the undulating cylinder 62 and the length of the wire 16 over time.

Next, the determination function unit 40b determines whether the calculated frictional force is the minimum value (step S9). If the frictional force is the minimum value (YES in step S9), the undulation angle at this point in 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 angular range, the undulation angle at which the frictional force exhibits the minimum value in the predetermined angular range is searched for and determined.

Finally, by raising or lowering the boom 14 to the position where the frictional force is the minimum value, the tip 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 boom tip position of this embodiment will be explained using the graph of FIG. 6. As described above, in this embodiment, the determination function unit 40b of the controller 40 determines whether the virtual frictional force, which is indirectly calculated based on the pressure of the undulating cylinder 62 and the change in the length of the wire 16 over time, is the minimum. At the point in time, it is determined that the tip of the boom 14 is located directly above the suspended load.

For example, when the tip of the boom 14 is located directly above the suspended load, as shown by the solid line in FIG. 6, the tension T at the same time becomes relatively small and the ground is cut by that amount The time is getting late. On the other hand, if the tip of the boom 14 is located at a position shifted from directly above the suspended load, the tension T at the same time becomes relatively large, as shown by the dashed line in FIG. The time of ground cutting will be earlier by 1 minute.

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

(1) As described above, the boom tip position prediction system S of this embodiment measures the boom 14 configured to be able to raise and lower freely, the luffing cylinder 62 that raises and lowers the boom 14, and the pressure in the luffing cylinder 62. a pressure measuring device 21 for measuring the length of the wire 16, a winch 13 for hoisting/lowering the suspended load via the wire 16, a wire length measuring device (22, 23) for measuring the length of the wire 16, a levitation cylinder 62, and the winch 13. The controller 40 is a control unit that controls the pressure of the undulating cylinder 62 measured by the pressure measuring device 21 and the length of the wire 16 measured by the length measuring device (22, 23). , and a controller 40 configured to predict the position of the tip of the boom 14. According to such a configuration, the tip position of the boom can be predicted with a simple configuration using existing sensors.

In other words, the pressure measuring device 21 and the length measuring device (rotation speed measuring device 22 and posture measuring device 23) are installed in the existing work equipment, but these measuring devices can be used to precisely determine the position of the tip of the boom 14. It becomes possible to efficiently perform ground cutting work including adjustment. That is, during ground cutting work, the suspended load can be lifted at high speed without swinging. Furthermore, since it becomes easier to determine whether the ground is cut off, the overall working time is shortened. Furthermore, since the number of parameters to be handled is small, it also leads to a reduction in test adjustment man-hours.

(2) Furthermore, it is preferable that the wire length measuring device includes a rotational speed measuring device 22 that measures the rotational speed of the winch 13 and an attitude measuring device 23 that measures the attitude of the boom 14. It is preferable that the attitude measuring device 23 includes a heave angle meter 23a that measures the heave angle of the boom 14, and a heave angular velocity meter 23b that measures the heave angular velocity.

(3) Furthermore, the controller 40 moves the boom 14 upward and/or downward, and determines the tip position of the boom 14 based on the pressure of the undulation cylinder 62 and the length of the wire 16 over time. It is designed to predict. 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) In addition, the controller 40 determines that when the boom 14 is moved upward and/or downward, the tip position of the boom 14 is suspended at the point in time when the indirectly calculated virtual frictional force is the minimum. Preferably, it is determined that the object is located directly above the load. With this configuration, it can be predicted based on the measured value that the tip of the boom 14 will be located directly above the suspended load.

(5) Furthermore, the controller 40 starts hoisting the wire 16 with the winch 13, and sets the state in which the pressure in the luffing cylinder 62 exceeds a predetermined threshold as an initial state, and adjusts the boom 14 based on this initial state. It is preferable that it be moved upwardly and/or downwardly. With this configuration, when the boom 14 is moved up and down in predictive control of the tip position, it is possible to prevent the boom 14 from unintentionally coming off the ground.

(6) Furthermore, the method for predicting the tip position of the boom in this embodiment includes the steps of moving the boom 14 upward and/or downward, measuring the pressure of the undulation cylinder 62, and the length of the wire 16. and predicting the boom tip position based on the pressure of the luffing cylinder 62 and the length of the wire 16. With such a configuration, the position of the tip of the boom can be predicted through a simple process using existing sensors.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes that do not depart from the gist of the present invention may be made to the present invention. included.

For example, although not particularly described in the embodiment, the boom tip position prediction system S of the present invention is applicable regardless of whether ground cutting is performed using the main winch as the winch 13 or when ground cutting is performed using a 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 invention is not limited to this. It is also possible to measure the direction of the load (that is, the direction in which the wire 16 extends) by attaching a load cell to the sheave.

S: Boom tip position prediction system;
1: Rough terrain crane; 10: Vehicle body; 12: Swivel platform;
13: winch; 14: boom; 16: wire; 17: hook;
20: Start switch; 21: Pressure measuring device;
22: Rotation speed measuring device (part of wire length measuring device);
23: Posture measuring device (part of wire length measuring device);
40: Controller;
51: Swivel lever; 52: Lifting lever;
53: Telescopic lever; 54: Winch lever;
61: Swivel motor; 62: Lifting cylinder;
63: Telescopic cylinder; 64: Winch motor

Claims (4)

A boom configured to rise and fall freely,
a hoisting cylinder for hoisting the boom;
a pressure measuring device that measures the pressure of the undulation cylinder;
A winch that hoists/lowers a suspended load via wire,
a wire length measuring device 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 device and the length of the wire measured by the wire length measuring device, a control unit configured to predict a tip position of the boom;
Equipped with
The control unit moves the boom upwardly and/or downwardly, and predicts the tip position of the boom based on changes over time in the pressure of the undulating cylinder and the length of the wire. A system for predicting the position of the tip of the boom. The boom tip position according to claim 1, wherein the wire length measuring device includes a rotational speed measuring device that measures the rotational speed of the winch and an attitude measuring device that measures the attitude of the boom. prediction system. The control unit controls the boom at a time when the virtual frictional force |ΔFsinφ| , which is indirectly calculated by equation (1) , becomes the minimum when the boom is moved upward and/or downward. The boom tip position prediction system according to claim 1 , wherein the boom tip position is determined to be located directly above the suspended load.

(In formula (1), T is the wire tension, γ is the winch rotation speed, θ ₀ is the initial heave angle, θ (dot) is the heave angular speed, L is the boom length, and k, k' are the wire elongation coefficients. , respectively.) The control unit starts hoisting the wire by the winch, and defines a state in which the pressure in the undulating cylinder becomes equal to or higher than a predetermined threshold as an initial state, and moves the boom upward and/or with respect to the initial state. The system for predicting the tip position of a boom according to claim 1 or 3 , wherein the boom tip position is moved upwardly and downwardly.

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