The present invention relates to a ground cutting control device and a crane for suppressing load runout when lifting a suspended load from the ground.
Background technology
[0002]
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 horizontally. "Runout" is a problem (see Fig. 1).
[0003]
For the purpose of preventing load shake during ground cutting, for example, the vertical ground cutting control device described in Patent Document 1 detects the engine rotation speed by an engine rotation speed sensor and raises and lowers the boom. It is configured to correct 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.
Prior art literature
Patent documents
[0004]
Patent Document 1: Japanese Unexamined Patent Publication No. 8-188379
Outline of the invention
Problems to be solved by the invention
[0005]
However, in the conventional ground cutting control device including Patent Document 1, two actuators are used in combination so as to keep the working radius constant by winding the wire with a winch by the amount of extension and increasing the undulation angle of the boom. I was in control. Therefore, there is a problem that it takes time to cut the ground due to complicated control.
[0006]
An object of the present invention is to provide a ground cutting control device capable of quickly grounding a suspended load while suppressing load runout, and a crane equipped with a ground cutting control device.
Means to solve problems
[0007]
In order to achieve the above object, the ground cutting control device of the present invention is
A boom that can be undulated and
A winch that winds up and unwinds a suspended load via a wire,
A load measuring means for measuring the load acting on the boom,
While controlling the operation of the boom and the winch, when the winch is wound up and the suspended load is grounded, the amount of change in the undulation angle of the boom is obtained based on the time change of the measured load, and the amount of change is obtained. The control unit that raises the boom to supplement the
Equipped with.
[0008]
The crane of the present invention is provided with the above-mentioned ground cutting control device.
The invention's effect
[0009]
According to the present invention, the suspended load can be quickly cut off while suppressing the load runout.
A brief description of the drawing
[0010]
[FIG. 1] FIG. 1 is an explanatory diagram illustrating load runout of a suspended load.
FIG. 2 is a side view of a mobile crane.
FIG. 3 is a block diagram of a ground cutting control device.
FIG. 4 is a block diagram of the entire ground cutting control device.
FIG. 5 is a block diagram of ground cutting control.
FIG. 6 is a flowchart of ground cutting control.
[FIG. 7] FIG. 7 is a graph illustrating a method for determining ground cutting.
[Fig. 8] Fig. 8 is a graph showing the relationship between load and undulation angle.
Embodiment for carrying out the invention
[0011]
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.
[0012]
Examples of cranes to which the ground cutting control device of the present invention can be applied include rough terrain cranes, all terrain cranes, truck cranes and the like. Hereinafter, in the present embodiment, a rough terrain crane which is a mobile crane will be described as an example, but the ground cutting control device according to the present invention can be applied to other cranes as well.
[0013]
(Structure of mobile crane)
First, the configuration of the mobile crane will be described using 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 swing table 12 mounted so as to be able to turn horizontally, and a boom 14 mounted behind the swing table 12.
[0014]
By expanding and contracting the slide cylinder, the out trigger 11 can slide out / slide outward from the vehicle body 10 in the width direction, and by expanding and contracting the jack cylinder, the jack can be extended / jack stored in the vertical direction from the vehicle body 10. Is.
[0015]
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 table 12 has a cockpit 18 arranged on the right front side and a counterweight 19 arranged on the rear side.
[0016]
Further, behind the swivel table 12, a winch 13 for winding / unwinding 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 (winding direction).
[0017]
The boom 14 is configured in a nested manner 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.
[0018]
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. ..
[0019]
(Control system configuration)
Next, the configuration of the control system of the ground cutting control device D of this embodiment will be described with reference to the block diagram of FIG. The ground cutting control device D 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 the actuators 61 to 64 (swivel motor 61, via a control valve (not shown)). The undulating cylinder 62, the telescopic cylinder 63, and the winch motor 64) are controlled.
[0020]
Further, the controller 40 of the present embodiment includes a ground cutting switch 20 for instructing the start / stop of the ground cutting control, a winch speed setting means 21 for setting the speed of the winch 13 in the ground cutting control, and a boom. The load measuring means 22 for measuring the load acting on the boom 14 and the posture detecting means 23 for detecting the posture of the boom 14 are connected to each other.
[0021]
The ground cutting switch 20 is an input device for instructing the start / stop of ground cutting control, and can be configured to be added to the safety device of the rough terrain crane 1, for example, and is arranged in the cockpit 18. Is preferable.
[0022]
The winch speed setting means 21 is an input device for setting the speed of the winch 13 in ground cutting control, and there are a method of selecting an appropriate speed from a preset speed and a method of inputting by a numeric keypad. Further, the winch speed setting means 21 can be configured to be added to the safety device of the rough terrain crane 1 like the ground cutting switch 20, and is preferably arranged in the cockpit 18. By adjusting the speed of the winch 13 by the winch speed setting means 21, the time required for ground cutting control can be adjusted.
[0023]
The load measuring means 22 is a measuring device for measuring the load acting on the boom 14, and for example, a pressure gauge for measuring the pressure acting on the undulating cylinder 62 can be applied. The pressure signal measured by the pressure gauge is transmitted to the controller 40.
[0024]
The posture detecting means 23 is a measuring device that detects the posture of the boom 14, and includes an undulation angle meter that measures the undulation angle of the boom 14 and an undulation angular velocity meter that measures the undulation angular velocity. Specifically, a potentiometer can be used as the undulation angle meter. Further, as the undulation angular velocity meter, a stroke sensor attached to the undulation cylinder 15 can be used. The undulation angle signal measured by the undulation angle meter and the undulation angular velocity signal measured by the undulation angular velocity meter are transmitted to the controller 40.
[0025]
The controller 40 is a control unit that controls the operation of the boom 14 and the winch 13, and is measured by the load measuring means 22 when the winch 13 is wound up and the suspended load is grounded by turning on the ground cutting switch 20. The amount of change in the undulation angle of the boom 14 is predicted based on the time change of the applied load, and the boom 14 is raised to compensate for the predicted amount of change.
[0026]
More specifically, the controller 40 has, as a functional unit, a characteristic table or a transfer function selection function unit 40a, and a ground cutting determination function for stopping the ground cutting control by determining whether or not the ground cutting has actually been performed. It has a portion 40b and.
[0027]
The selection function unit 40a of the characteristic table or the transfer function receives inputs of the initial value of the pressure from the pressure gauge as the load measuring means 22 and the initial value of the undulating angle from the undulating angle meter as the posture measuring means 23. To determine the characteristic table or transfer function to apply. Here, as the transfer function, a relationship using the linear coefficient a can be applied as follows.
[0028]
First, as shown in the load-undulation angle graph in FIG. 8, the load and the undulation angle (tip-to-ground angle) are adjusted so that the boom tip position is always directly above the suspended load so that load runout does not occur. ) Is known to have a linear relationship. Assuming that the load Load 1 changes to Road 2 between time t1 and time t2 during ground cutting, the undulation angles θ 1 and θ 2 at times t1 and t2 are expressed by Eq. (1). ..
[Number 1]

[0029]
When the difference equation is obtained from the difference between the two equations, the difference Δθ of the undulation angles θ 1 and θ 2 is expressed by equation (2).
[Number 2]

[0030]
In order to control the undulation angle, it is necessary to give the undulation angular velocity. The undulation angular velocity V Drc is expressed by the equation (3).
[Number 3]

Here, a is a constant (linear coefficient).
That is, in the undulation angle control, the time change (derivative) of the load is input.
[0031]
The ground cutting determination function unit 40b monitors the time-series data of the load value calculated from the pressure signal from the pressure gauge as the load measuring means 22, and determines the presence or absence of ground cutting. The method of determining the ground cutting will be described later with reference to FIG. 7.
[0032]
(Overall block diagram)
Next, using the block diagram of FIG. 4, the input / output relationship between all the elements including the ground cutting control of this embodiment will be described in detail. First, the load change calculation unit 71 calculates the load change based on the time series data of the load measured by the load measuring means 22. The calculated load change is input to the target shaft velocity calculation unit 72. The input / output relationship in the target axis speed calculation unit 72 will be described later with reference to FIG.
[0033]
The target shaft speed calculation unit 72 calculates the target shaft speed based on the initial value of the undulation angle, the set winch speed, and the input load change. The target axis velocity is here the target undulation angular velocity (and, but not required, the target winch velocity). The calculated target axis speed is input to the axis speed controller 73. The control of the first half up to this point is the process related to the ground cutting control of this embodiment.
[0034]
After that, the operation amount is input to the control target 75 via the axis speed controller 73 and the operation amount conversion processing unit 74 of the axis speed. The control of the latter half is a process related to normal control, and feedback control is performed based on the measured undulation angular velocity.
[0035]
(Block diagram of ground cutting control)
Next, using the block diagram of Fig. 5, especially the ground cutting system The input / output relationship of the elements in the target axis velocity calculation unit 72 will be described. First, the initial value of the undulation angle is input to the selection function unit 81 (40a) of the characteristic table / transfer function. In the selection function unit 81, the most appropriate constant (linear coefficient) a is selected by using a characteristic table (lookuptable) or a transfer function.
[0036]
Then, in the numerical differentiation unit 82, the numerical differentiation (differentiation with respect to time) of the load change is performed, and the target undulation angle velocity is calculated by multiplying the result of this numerical differentiation by the constant a. That is, the target undulation angular velocity is calculated by executing the above-mentioned calculation (Equation 3). In this way, the control of the target undulation angular velocity is feedforward controlled using the characteristic table (or transfer function).
[0037]
(flowchart)
Next, the overall flow of the ground cutting control of this embodiment will be described using the flowchart of FIG.
[0038]
First, the operator presses the ground cutting switch 20 to start the ground cutting control (Start). At this time, the target speed of the winch 13 is set via the winch speed setting means 21 before or after the start of the ground cutting control. Then, the controller 40 starts winch control at the target speed (step S1).
[0039]
Next, at the same time that the winch 13 is wound up, the suspended load measurement is started by the load measuring means 22, and the load value is input to the controller 40 (step S2). Then, the selection function unit 40a receives the input of the initial value of the load and the initial value of the undulation angle from the undulation angle meter 23 as the posture measuring means, and determines the characteristic table or the transfer function to be applied ( Step S3).
[0040]
Next, the controller 40 calculates the undulation angular velocity based on the applied characteristic table or transfer function and the load change (step S4). That is, the undulation angular velocity is controlled by the feedforward control.
[0041]
Then, the controller 40 determines the presence or absence of ground cutting based on the time-series data of the measured load (step S5). The determination method will be described later. As a result of the determination, if the ground is not cut (NO in step S5), the process returns to step S2, and the controller 40 repeats feedforward control based on the load (steps S2 to S5).
[0042]
As a result of the determination, if the ground is cut off (YES in step S5), the controller 40 slowly stops the ground cutting control (step S6). That is, the rotary drive of the winch 13 by the winch motor is stopped while slowing down, and the undulating drive by the undulating cylinder 62 is stopped while slowing down.
[0043]
(Judgment of ground cutting)
Next, using the graph of FIG. 7, the method of determining the ground cutting of this embodiment will be described. In this embodiment, the controller 40 monitors the time-series data of the measured load while winding the winch 13 in the ground-cutting control, and captures the first maximum value of the time-series data to ground-cutting. It is designed to be judged as having been done.
[0044]
More specifically, as shown in FIG. 7, in general, when the time series of load data is taken, it overshoots at the moment after the ground cutting, then undershoots, and then continues to vibrate. .. Therefore, by capturing the time of the peak of the first peak of vibration, that is, the first maximum value, it is possible to determine that the ground has been cut. However, in reality, at the time when the first maximum value is recorded, which is the time when it is determined that the ground is cut off, it is considered that the vehicle is slightly overshooting due to the inertial force.
[0045]
(effect)
Next, the effects of the ground cutting control device D of this embodiment will be listed and described.
[0046]
(1) As described above, the ground cutting control device D of the present embodiment controls the operation of the boom 14, the winch 13, the load measuring means 22, the boom 14 and the winch 13, and winds up the winch 13. The controller 40 as a control unit that obtains the amount of change in the undulation angle of the boom 14 based on the time change of the measured load when cutting the suspended load, and raises the boom 14 to compensate for the change. And have. According to the ground cutting control device D, the suspended load can be quickly grounded while suppressing the load runout.
[0047]
That is, in the ground cutting control device D of the present embodiment, attention is paid to the linear relationship between the load and the undulation angle, and the feedforward control is performed based only on the time change of the load value, as in the conventional case. Suspended loads can be quickly grounded without the need for complicated feedback control.
[0048]
(2) Further, the posture measuring means 23 for measuring the posture of the boom 14 is further provided, and the controller 40 has an initial value of the undulation angle of the measured boom 14 (initial value of the posture) and an initial value of the measured load. And, the corresponding characteristic table or transfer function is selected based on, and the change amount of the undulation angle of the boom 14 is obtained from the time change of the measured load by using the characteristic table or the transfer function. Is preferable.
[0049]
With this configuration, at the start of ground cutting control, the winch 13 is wound at a constant speed, the undulation angle control amount is calculated from the characteristic table (or transfer function) according to the load change, and feedforward control is performed. Therefore, it is possible to quickly cut the ground without shaking. In addition, by reducing the number of parameters to be adjusted, factory adjustment can be performed quickly and easily.
[0050]
(3) Further, it is preferable that the controller 40 controls the winch 13 so that the winch 13 is wound at a constant speed when the winch 13 is wound up and the suspended load is grounded. With this configuration, it is possible to facilitate the ground cutting determination by suppressing the influence of disturbance such as inertial force and stabilizing the response (measured load value).
[0051]
(4) Further, it is preferable that the controller 40 adjusts the time required for ground cutting by adjusting the speed of the winch 13 when the winch 13 is wound up and the suspended load is grounded. With this configuration, it is possible to work safely and efficiently by selecting an appropriate winch 13 speed according to the weight of the suspended load and the environmental conditions.
[0052]
(5) Further, the controller 40 of the present embodiment monitors the time-series data of the measured load when the winch 13 is wound up and the suspended load is grounded, and captures the first maximum value of the time-series data. It is judged that the ground has been cut. By controlling based only on the load in this way, it is possible to easily and quickly determine the ground cutting.
[0053]
(6) Further, the rough terrain crane 1 which is the mobile crane of the present embodiment is provided with any of the above-mentioned ground cutting control devices D, so that the suspended load is quickly grounded while suppressing the load runout. It is possible to carry out crane work safely and efficiently.
[0054]
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 made in the present invention. included.
[0055]
For example, although not particularly described in the examples, the ground cutting control device D of the present invention is applied regardless of whether the ground cutting is performed using the main winch as the winch 13 or the ground cutting using the sub winch. be able to.
[0056]
All disclosures of the specification, drawings and abstract contained in Japanese application of Japanese Patent Application No. 2019-024610 filed on February 14, 2019 are incorporated herein by reference.
Description of the sign
[0057]
D Ground cutting control device
A Linear coefficient
1 Rough terrain crane
10 car body
12 swivel table
13 winch
14 boom
16 wire
17 hook
20 Ground cutting switch
21 winch speed setting means
22 Load measuring means
23 Posture detection means
40 controller
40a selection function unit
40b Ground cutting judgment function unit
51 swivel lever
52 undulating lever
53 Telescopic lever
54 winch lever
61 swivel motor
62 undulating cylinder
63 Telescopic cylinder
64 winch motor
The scope of the claims
[Claim 1]
A boom that can be undulated and
A winch that winds up and unwinds a suspended load via a wire,
A load measuring means for measuring the load acting on the boom,
While controlling the operation of the boom and the winch, when the winch is wound up and the suspended load is grounded, the amount of change in the undulation angle of the boom is obtained based on the time change of the measured load, and the amount of change is obtained. The control unit that raises the boom to supplement the
A ground cutting control device equipped with.
[Claim 2]
Further equipped with a posture measuring means for measuring the posture of the boom,
The control unit selects a corresponding characteristic table or transfer function based on the measured initial value of the boom posture and the measured initial value of the load, and uses the characteristic table or transfer function. The ground cutting control device according to claim 1, wherein the amount of change in the undulation angle of the boom is obtained from the time change of the measured load.
[Claim 3]
The ground cutting control device according to claim 1 or 2, wherein the control unit controls the winch so that the winch is wound up at a constant speed when the winch is wound up and the suspended load is grounded.
[Claim 4]
The one according to any one of claims 1 to 3, wherein the control unit adjusts the time required for ground cutting by adjusting the speed of the winch when the winch is wound up and the suspended load is grounded. Ground cutting control device.
[Claim 5]
When the winch is wound up and the suspended load is grounded, the control unit monitors the time-series data of the measured load, catches the first maximum value of the time-series data, and determines that the ground is cut. The ground cutting control device according to any one of claims 1 to 4.
[Claim 6]
A crane provided with the ground cutting control device according to any one of claims 1 to 5.