JP2022084958A - Dynamic lift off determination device, dynamic lift off control device, and mobile crane - Google Patents

Abstract

To provide a dynamic lift off determination device capable of determining the dynamic lift off quickly by a simple method while suppressing swinging of a load.SOLUTION: A dynamic lift off determination device C includes a boom 14 which is constituted to be elevated and lowered, a winch 13 hoisting/lowering a suspended load through a wire rope 16, load measurement means 22 for measuring a load applied to the boom 14, a flexural vibration filter 31 attenuating flexural vibration components of the boom 14 included in load data, and a control unit 40 controlling the boom 14 and the winch 13. The dynamic lit off determination device determines the dynamic lift off based on the temporal change of the load data about the passage of the flexural vibration filter 31 when performing the dynamic lift off of the suspended load by hoisting the winch 13.SELECTED DRAWING: Figure 2

Description

The present invention relates to a ground cutting determination device for suppressing load runout when lifting a suspended load from the ground.

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. "Load runout" has become a problem (see Fig. 1).

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.

Japanese Unexamined Patent Publication No. 8-188379

The conventional ground cutting control device including Patent Document 1 determines the ground cutting based on the time series of the load data. However, the time series of load data vibrates greatly due to the influence of the bending vibration of the boom. Therefore, it is necessary to wait until the load data becomes stable, which is a factor that takes time to determine the ground cutting.

Therefore, an object of the present invention is to provide a ground cutting determination device, a ground cutting control device, and a mobile crane, which can quickly determine ground cutting by a simple method while suppressing load shake. It is supposed to be.

In order to achieve the above-mentioned object, the ground cutting determination device of the present invention has a boom configured to be undulating, a winch for hoisting / hoisting a suspended load via a wire rope, and a load acting on the boom. A load measuring means for measuring, a bending vibration filter for dampening the bending vibration component of the boom included in the load data, and a control unit for controlling the boom and the winch, and the winch is wound up to cut the suspended load. A control unit is provided so as to determine the ground cutting based on the time change of the load data passed through the deflection vibration filter.

Further, the ground cutting control device of the present invention is a ground cutting control device provided with a ground cutting determination device, and the control unit measures the load measured 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, and the boom is undulated so as to compensate for the amount of change.

As described above, the ground cutting determination device of the present invention is a boom, a winch, a load measuring means, a deflection vibration filter, and a control unit for controlling the boom and the winch, and winds the winch to ground the suspended load. At that time, the ground cutting is determined based on the time change of the load data passed through the deflection vibration filter. With such a configuration, it is possible to quickly determine the ground cutting by a simple method while suppressing load shake.

Further, the ground cutting control device of the present invention is a ground cutting control device including a ground cutting determination device, and the control unit is a boom undulation angle based on a time change of a measured load at the time of ground cutting. The amount of change is calculated, and the boom is undulated to compensate for the amount of change. With such a configuration, it is possible to quickly determine the ground cut and quickly cut the suspended load while suppressing the load runout.

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 a ground cutting control device. It is a graph which shows the relationship of a load-the undulation angle. It is a block diagram of the whole of the ground cutting control device. It is a block diagram of the ground cutting control. It is a flowchart of the ground cutting control. It is a graph explaining the concept of the ground cutting determination.

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.

Examples of the mobile crane of this embodiment include rough terrain cranes, all terrain cranes, and truck cranes. Hereinafter, a rough terrain crane will be described as an example of the work vehicle according to the present embodiment, but the safety device according to the present invention can also be applied to other mobile cranes.

(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 swing table 12 mounted so as to be able to turn horizontally, and a boom 14 mounted behind the swing table 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 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 table 12 has a cockpit 18 arranged on the right front side and a counterweight 19 arranged on the rear side.

Further, behind the swivel table 12, a winch 13 for hoisting / 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).

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 a 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 rope 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 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.

Further, the controller 40 of the present embodiment includes a ground cutting switch 20 for starting / stopping 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 14. The load measuring means 22 for measuring the acting load and the posture detecting means 23 for detecting the posture of the boom 14 are connected.

The ground cutting switch 20 is an input device for instructing the start or 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.

The winch speed setting means 21 is an input device for setting the speed of the winch 13 in ground cutting control, and includes a method of selecting an appropriate speed from preset speeds 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.

The load measuring means 22 is a measuring device for measuring the load acting on the boom 14, and can be, for example, a pressure gauge (22) for measuring the pressure acting on the undulating cylinder 62. The pressure signal measured by the pressure gauge (22) is transmitted to the controller 40 via the deflection vibration filter 31 and / or the undulation angle vibration filter 32.

Here, the deflection vibration filter 31 is installed for the purpose of removing the influence of the deflection vibration component of the boom 14 and accurately monitoring the load acting on the original wire rope 16. The deflection vibration filter 31 may be, for example, a so-called bandpass filter that passes a specific frequency or a so-called bandstop filter that attenuates a specific frequency. The deflection vibration filter 31 can be realized by an electric circuit or the like in terms of hardware, or can be realized numerically (in terms of software) by spectrum analysis.

Then, in the deflection vibration filter 31 of this embodiment, the natural frequency due to the deflection is obtained in advance for each length and undulation angle of the boom 14 by experimental measurement or numerical calculation, and this is stored in a database. Then, the deflection vibration component is attenuated by reading the corresponding natural frequency from the database according to the actual length (that is, initial length) and undulation angle (that is, initial undulation angle) of the boom 14 at the time of ground cutting. It is configured to do.

Further, the undulation angle vibration filter 32 is installed for the purpose of removing the influence of the undulation angle control of the boom 14 and accurately monitoring the original load acting on the wire rope 16. That is, when the undulation angle control is executed, a time delay occurs between the input and the output due to the magnitude of the moment of inertia and the load torque, and the response becomes oscillating. Therefore, the undulation angle vibration filter 32 is configured to obtain the response characteristic of the undulation angle control by experimental measurement or numerical calculation in advance and remove the influence of the corresponding frequency band.

The undulation angle vibration filter 32 may be a bandpass filter or a bandstop filter, similarly to the deflection angle vibration filter 31. Further, the undulating angular vibration filter 32 can be realized by hardware or numerically (software). Further, it is preferable that the undulation angle vibration filter 32 is stored in a database for each length and undulation angle of the boom 14 in advance.

The posture detecting means 23 is a measuring device for detecting the posture of the boom 14, and although not shown, the undulation angle meter 231 for measuring the undulation angle of the boom 14, the undulation angular velocity meter 232 for measuring the undulation angular velocity, and the boom 14 It is composed of a length meter 233 for measuring the length. Specifically, a potentiometer can be used as the undulation angle meter 231. Further, as the undulation angular velocity meter 232, a stroke sensor attached to the undulation cylinder 15 can be used. The undulation angle signal measured by the undulation angle meter 231 and the undulation angular velocity signal measured by the undulation angular velocity meter 232 are transmitted to the controller 40. Further, the boom length signal measured by the length meter 233 is transmitted to the filter 31 (32) in addition 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 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 undulated so as to compensate for the predicted amount of change.

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.

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 22 as the load measuring means and the initial value of the undulating angle from the undulating angle meter 23 as the attitude measuring means. 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.

First, as shown in the load-undulation angle graph in FIG. 4, the load and 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 changed to Load ₂ between _time t1 and time t2 during the _ground cutting,

If you find the difference equation from the difference between the two equations,

ここで、ａは定数（線形係数）である。
すなわち、起伏角制御は、荷重の時間変化（微分）が入力になる。 In order to control the undulation angle, it is necessary to give the undulation angular velocity.

Here, a is a constant (linear coefficient).
That is, in the undulation angle control, the time change (derivative) of the load is input.

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 22 as the load measuring means, and determines the presence or absence of ground cutting. The method of determining the ground cutting will be described later with reference to FIG.

(Overall block diagram)
Next, using the block diagram of FIG. 5, 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.

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.

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.

(Block diagram of ground cutting control)
Next, the input / output relationship of the elements in the target axis velocity calculation unit 72 of the ground cutting control will be described with reference to the block diagram of FIG. 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.

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).

(flowchart)
Next, the entire flow of the ground cutting control of this embodiment will be described with reference to the flowchart of FIG. 7.

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).

Next, at the same time as the winch 13 is wound up, the load measuring means 22 starts the suspended load measurement, 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 attitude measuring means, and determines the characteristic table or the transfer function to be applied ( Step S3).

Next, in the controller 40, the undulation angular velocity is calculated 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.

Then, the time-series data of the measured load is input via the filter 31 (32), and the presence or absence of ground cutting is determined based on the time-series data (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 feedforward control based on the load is repeated (steps S2 to S5).

As a result of the determination, if the ground is cut (YES in step S5), the ground cutting control is slowly stopped (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.

(Judgment of ground cutting)
Next, with reference to FIG. 8, the ground cutting determination device C and the ground cutting determination method of this embodiment will be described in detail. The ground cutting determination device C includes a boom 14, a winch 13, a load measuring means 22, a deflection vibration filter 31, an undulation angle vibration filter 32, and a controller 40 as a control unit for controlling the boom 14 and the winch 13. It is composed.

In the ground cutting control, the controller 40 of the present embodiment grounds based on the time change of the load data passed through the deflection vibration filter 31 and the undulating angular vibration filter 32 when the winch 13 is wound up and the suspended load is grounded. It is designed to judge the cut. Here, the deflection vibration filter 31 and the undulation angle vibration filter 32 are called from the table according to the initial length and the initial undulation angle of the boom 14 at the start of the ground cutting control.

In this way, as shown in the graph of FIG. 8, the boom 14 of the time series (dotted line in the figure) of the load data affected by the deflection vibration is passed through the deflection vibration filter 31 and the undulation angle vibration filter 32. The vibration component (unevenness) caused by bending is attenuated, and a relatively smooth time series of load data (solid line in the figure) can be obtained.

Here, any method may be used for determining ground cutting based on the load data that has passed through the deflection vibration filter 31 and the undulation angle vibration filter 32. For example, as a ground cutting determination method, the moving average of the time change (slope) of the load data is monitored, and the moving average of this time change becomes a predetermined amount or less (that is, the slope is larger than the predetermined slope). By capturing the (relaxed) state, it is possible to determine that the ground has been cut. Alternatively, for example, 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.

Then, in this embodiment, as described with reference to FIGS. 6 and 7, the relationship between the load change and the control amount (undulation angular velocity) becomes theoretically linear by implementing the feedforward control. Therefore, it can be said that the compatibility is particularly good. That is, by passing through the filters 31 and 32, the linearity of the load data becomes clearer, so that it becomes easier to grasp the load change and control the undulation angular velocity.

(effect)
Next, the effects of the ground cutting determination device C, the ground cutting control device D, and the rough terrain crane 1 as a mobile crane of this embodiment will be listed and described.

(1) As described above, in the ground cutting determination device C of the present embodiment, the boom 14 configured to be undulating, the winch 13 for hoisting / unwinding the suspended load via the wire rope 16, and the boom 14 The load measuring means 22 for measuring the load acting on the load, the bending vibration filter 31 for dampening the bending vibration component of the boom 14 included in the load data, and the controller 40 for controlling the boom 14 and the winch 13, which is the winch 13. The controller 40 is provided with a controller 40 that determines the ground cutting based on the time change of the load data passed through the deflection vibration filter 31 when the suspended load is wound up and ground-cut. With such a configuration, the influence of the deflection angle vibration component is reduced from the time series of the load data, and based on the more accurate load data, the load runout is suppressed and quickly by a simple method. It is possible to determine the ground cutting.

(2) Further, the deflection vibration filter 31 obtains and stores the natural frequency due to the deflection for each length and undulation angle of the boom 14 in advance, and stores it according to the length and undulation angle of the boom 14 at the time of ground cutting. It is configured to attenuate the corresponding deflection vibration component. Therefore, by attenuating the deflection angle vibration component according to the length of the boom 14, the deflection angle vibration component can be attenuated more accurately.

(3) Further, the undulation angle vibration filter 32 for attenuating the bending vibration component by the undulation angle control included in the load data is further provided, and the controller 40 winds up the winch 13 and cuts the suspended load on the ground. The ground cutting is determined based on the time change of the load data passed through the filter 32. Therefore, by attenuating the vibration component of the response due to the moment of inertia and the load torque when the undulation angle control is executed, it becomes possible to quickly determine the ground cutting based on the more accurate load data.

(4) Further, the ground cutting control device D of the present embodiment is a boom 14, a winch 13, a load measuring means 22, and a controller 40 as a control unit for controlling the boom 14 and the winch 13, and is a winch 13. The controller 40, which obtains the amount of change in the undulation angle of the boom 14 based on the time change of the measured load when hoisting and cutting the suspended load, and undulates the boom 14 so as to compensate for the change. I have. With such a configuration, it is a ground cutting control device D capable of quickly grounding a suspended load while suppressing load runout.

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 compensation amount, and the feedforward control is performed based only on the time change of the load value. It is possible to quickly cut the suspended load without implementing complicated feedback control as in the case of.

(5) Further, the posture measuring means 23 for measuring the posture of the boom 14 is further provided, and the controller 40 responds based on the measured initial value of the posture of the boom 14 and the measured initial value of the load. It is preferable to select a characteristic table or transfer function and use the characteristic table or transfer function to obtain the amount of change in the undulation angle of the boom 14 from the time change of the measured load.

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 feed forward 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.

(6) Further, it is preferable that the controller 40 is configured to wind the winch 13 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).

(7) 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 determination device C or ground cutting control device D, so that the load can be swung quickly. It is a rough terrain crane 1 that can cut the suspended load.

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.

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.

C: Ground cutting determination device; D: Ground cutting control device; a: Linear coefficient;
1: Rough terrain crane; 10: Body; 12: Swing platform;
13: Winch; 14: Boom; 16: Wire; 17: Hook;
20: Ground cutting switch;
21: Winch speed setting means;
22: Pressure gauge (load measuring means);
23: Ups and downs angle meter (posture detection means);
31: Deflection vibration filter; 32: Ups and downs angle vibration filter;
40: Controller;
40a: Selection function unit; 40b: Ground cutting determination function unit;
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 (8)

A boom that can be undulated and
A winch that winds up / unwinds a suspended load via a wire rope,
A load measuring means for measuring the load acting on the boom, and
A deflection vibration filter that attenuates the deflection vibration component of the boom included in the load data,
A control unit that controls the boom and the winch so that when the winch is wound up and the suspended load is grounded, the ground cutting is determined based on the time change of the load data passed through the deflection vibration filter. The control unit and
A ground cutting determination device. The deflection vibration filter obtains and stores the natural frequency due to deflection for each boom length and undulation angle in advance, and corresponds to the deflection vibration component according to the boom length and undulation angle at the time of ground cutting. The ground cutting determination device according to claim 1, which is configured to attenuate the ground. An undulation angle vibration filter that attenuates bending vibration components by undulation angle control included in the load data is further provided, and the control unit passes the undulation angle vibration filter when the winch is wound up and the suspended load is grounded. The ground cutting determination device according to claim 1 or 2, wherein the ground cutting is determined based on the time change of the load data. A ground cutting control device including the ground cutting determination device according to any one of claims 1 to 3.
When the winch is wound up and the suspended load is grounded, the control unit obtains the amount of change in the undulation angle of the boom based on the time change of the measured load, and the boom is compensated for the amount of change. A ground cutting control device that is designed to undulate. 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 4, wherein the amount of change in the undulation angle of the boom is obtained from the time change of the measured load. The ground cutting control device according to claim 4 or 5, wherein the control unit winds up the winch at a constant speed when hoisting the winch to ground the suspended load. A mobile crane provided with the ground cutting determination device according to any one of claims 1 to 3. A mobile crane provided with the ground cutting control device according to any one of claims 4 to 6.

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