JPH0891774A - Method and device for swing stop control of crane - Google Patents

Abstract

PURPOSE: To function a load swing suppression including a load swing produced by a force specific to swing motions such as centrifugal force and Coriolis force. CONSTITUTION: In a swing angular acceleration calculating means 18, a fundamental control time required to stop a swing body is obtained from a natural frequency of a lifted load which was obtained from a rope length, the fundamental control time is multiplied by a coefficient of correction pre-determined by a relation with a swing speed considering a swing of the lifted load caused by a swing motion so as to obtain a correction control time. Also, in a braking torque calculating means 19, a braking torque is obtained from the correction control time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swing stop control method and apparatus for automatically stopping a swing body while suppressing swing of a suspended load in a swing crane.

[0002]

2. Description of the Related Art In general, a swing crane has an upper swing body mounted on a lower traveling body so as to be swingable around a vertical axis.
A boom is attached to the upper swing body so that it can be raised and lowered.

Conventionally, in such a swing crane, as a technique for automatically stopping the swing motion of the swing structure, Japanese Patent Laid-Open Publication No. Sho 62-13619 and Japanese Utility Model Laid-Open No. 61-19.
As disclosed in Japanese Patent No. 7089, it is known that the moment of inertia of a revolving structure is detected and a braking force is applied based on the moment of inertia.

However, in these prior arts, since the swing of the suspended load with respect to the upper swing body is not taken into consideration, there is a difference between the theoretical deceleration and the actual deceleration, and a large load is generated even after the swing body is stopped. There was a problem that swings remained.

Therefore, as disclosed in Japanese Unexamined Patent Publication No. 4-153197, the vehicle is turning based on the turning speed and the length of the suspension rope suspended from the boom point (hereinafter referred to as the rope length). A technique has been proposed in which the swing state of the suspended load is calculated and a braking torque is applied according to the swing state of the suspended load.

In this known technique, the control time (time required for turning stop control) is obtained by the natural frequency determined from the rope length, and the turning angular acceleration for deceleration is calculated from this control time and the present turning speed. The braking torque is calculated and the braking torque is calculated based on the calculated torque.

[0007]

However, in this method, since only the pendulum motion of the suspended load due to the linear motion is regarded as the swing of the suspended load, it is effective in suppressing the swing of the load due to the linear motion, but Since the force (centrifugal force, Coriolis force) generated by the motion is not taken into consideration at all, the swing in the swing direction of the suspended load due to this swing is not suppressed, and it is intended to stop the load as little as possible. The objective was still not fully met.

[0008] Therefore, the present invention provides a method and a device for controlling the turning of a crane, which can obtain an effect of suppressing a load shake including a load shake peculiar to a turning motion.

[0009]

The invention (method) of claim 1
Determines the natural frequency of the suspended load from the length of the suspension rope hung from the boom point, and from this natural frequency the basic control time required to stop the revolving structure. , The correction control time is obtained by multiplying the correction coefficient that is determined in advance with the turning speed as a coefficient considering the swing of the suspended load due to the turning motion, and the turning body is stopped based on this correction control time and the turning speed of the turning body. The turning angular acceleration for calculating the turning angular acceleration is calculated, the braking torque for obtaining the turning angular acceleration is calculated, and the turning structure is braked based on the braking torque.

According to the second aspect of the present invention, the natural frequency of the suspended load is obtained from the length of the suspension rope suspended from the boom point, and the basic control time required to stop the revolving structure is determined from this natural frequency. Then, this basic control time is multiplied by a primary correction coefficient that has been determined in advance as a coefficient in consideration of the swing of the suspended load due to the turning motion in relation to the turning speed to obtain the primary correction control time. To obtain the secondary correction control time by multiplying by the secondary correction coefficient determined according to the swinging state of the suspended load at the start of control,
While calculating the turning angular acceleration for stopping the revolving structure from the secondary correction control time and the revolving speed of the revolving structure,
The braking torque for obtaining the turning angular acceleration is calculated, and the revolving structure is braked based on the braking torque.

According to a third aspect of the invention (apparatus), the rope length detecting means for detecting the length of the suspension rope suspended from the boom point, the swing speed detecting means for detecting the swing speed of the boom, and the swing body are provided. Based on the calculated braking torque, a turning angular acceleration calculation means for calculating the turning angular acceleration for stopping, a braking torque calculation means for calculating the braking torque of the swing structure based on the calculated turning angular acceleration, The swing angular acceleration calculating means obtains the natural frequency of the suspended load from the rope length detected by the rope length detecting means, and the natural frequency is also provided. From this, the basic control time required to stop the revolving structure is obtained, and this basic control time is set in advance as a coefficient considering the swing of the suspended load due to the swing motion and the swing speed. It is multiplied by the correction coefficient which is determined with the engagement, but that is configured to obtain a correction control time for calculating the slewing angular acceleration.

According to a fourth aspect of the present invention, a rope length detecting means for detecting the length of the suspension rope suspended from the boom point, a swing speed detecting means for detecting the swing speed of the boom, and a suspending rope at the start of control. A swinging state detecting means for detecting a swinging state of a load, a swinging angular acceleration calculating means for calculating a swinging angular acceleration for stopping the swinging body, and a braking torque for the swinging body based on the calculated swinging angular acceleration Braking torque calculation means and motor pressure control means for controlling the pressure of the swing motor based on the calculated braking torque, wherein the swing angular acceleration calculation means is the rope detected by the rope length detection means. The natural frequency of the suspended load is calculated from the length, and the basic control time required to stop the revolving structure is calculated from this natural frequency. Therefore, the primary correction control time for calculating the above-mentioned turning angular acceleration is calculated by multiplying the primary correction coefficient determined in advance with the relationship with the turning speed as a coefficient considering the swing of the suspended load. The secondary correction control time is obtained by multiplying the secondary correction coefficient determined according to the shake state of the suspended load at the control start time detected by the shake state detecting means.

According to the first and third aspects of the invention, the basic control time calculated based on the shake of the load due to the linear motion is multiplied by the correction coefficient in consideration of the shake of the load due to the turning motion to calculate the correction control time. Since the braking torque is obtained based on the correction control time, it is possible to deal with the load shake including the load shake due to the turning motion.

That is, it is possible to perform highly accurate stop control that minimizes the load shake remaining after the turning stop.

However, in this configuration, since the swing of the suspended load at the start of control due to disturbance such as wind (hereinafter referred to as initial load swing) is not taken into consideration, the turning stop is caused when the initial load swing occurs. The remaining load swing (residual load swing) is still large.

On the other hand, according to the structures of claims 2 and 4, the initial load shake is detected, and the correction control time (first-order correction control time) further depends on the state of the initial load shake (the shake angle and the shake direction). The secondary correction control time is calculated by multiplying the determined secondary correction coefficient, and the braking torque is calculated based on this, so even if there is an initial load shake, the residual load shake is minimized High stop control can be realized.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment (see FIGS. 1 to 13) FIG. 13 shows a swing crane to which the present invention is applied.

In the figure, 1 is a lower traveling body, 2 is an upper revolving body mounted on the lower traveling body 1 so as to be rotatable around a vertical axis, and the upper revolving body 2 has N unit booms B.
An extendable and retractable boom B composed of 1 to BN is provided so as to be up and down around a boom foot pin 3, and a hanging rope 4 is hung from the tip (boom point) of the boom B.
The suspended load C is thus suspended.

In the following description, Bn (n = 1,
2, ... N) indicates the nth unit boom counted from the boom base end side.

As shown in FIG. 1, this crane includes a boom length sensor 5 for detecting a boom length Lb, a boom angle sensor 6 for detecting a boom angle (raising / lowering angle) φ, and a hoisting load sensor for detecting a hoisting load. 7. Length of hanging rope 4 (distance from boom point to hanging load center = swing radius of hanging load C) L
A rope length sensor 8 for detecting w and an angular velocity sensor 9 for detecting a turning angular velocity of the upper swing body 2 are provided, and signals from these sensor groups are input to the controller 10.

The controller 10 includes a lateral bending evaluation coefficient setting means 11 for setting an evaluation coefficient for lateral bending strength of the boom B, a boom length Lb and a boom angle φ detected by the boom length sensor 5 and the boom angle sensor 6. A turning radius calculating means 12 for calculating a turning radius R of the suspended load C based on the above, a boom inertia moment calculating means 13 for obtaining an inertia moment In of each unit boom Bn based on the boom length Lb and the boom angle φ, and a rated load. Calculation means 14,
Lifting load calculating means 15, load inertia moment calculating means 16, allowable angular acceleration calculating means 17, turning angular acceleration calculating means 18, braking torque calculating means 19, motor pressure control means 20, and hanging load angular acceleration. The calculation means 21 is provided, and control is performed to brake and stop the upper revolving superstructure 2 while leaving the runout of the suspended load C as small as possible while taking into consideration the lateral bending load generated in the boom B during turning braking.

The function of each of these means will be described in detail.

Turning radius calculating means 12 Based on the detected boom length Lb and boom angle φ, the turning radius R'without considering the bending of the boom B and the boom B
The radius increase ΔR due to the bending is calculated, and the turning radius R is calculated from both.

Boom inertia moment calculating means 13 The inertia moment In of each unit boom Bn is calculated, and the total inertia moment Ib of the boom B is calculated. The moment of inertia In of each unit boom Bn is calculated by the following equation.

[0025]

[Formula 1] In = In0 · cos ² φ + (Wn / g) · Rn ² Here, In0 is each unit boom Bn in the state of φ = 0.
Indicates a moment (constant) around the center of gravity of each unit, Wn is the own weight of each unit boom Bn, g is the acceleration of gravity, and Rn is the turning radius of the center of gravity of each unit boom Bn.

Rated load calculating means 15 Turning radius R calculated by turning radius calculating means 12
And the boom length Lb, the rated load W0 is calculated from the data stored in the rated load memory 22.

Lifting load calculating means 15 Based on the boom hoisting cylinder pressure p detected by the lifting load sensor 7, the turning radius R calculated by the turning radius calculating means 12, and the boom length Lb, The upper load W is calculated.

Load inertia moment calculating means 16 Lifting load W calculated by the lifting load calculating means 15
And the turning radius R, the inertia moment Iw of the load (suspended load C) is calculated.

Specifically, the load inertia moment Iw is expressed by the following equation.

[0030]

Based on Equation 2] Iw = (W / g) R 2 allowable angular acceleration calculation means 17 above manner was calculated the data, calculates the allowable angular acceleration β1 in the following manner.

Generally, the upper swing body 2 and the boom B of the swing crane have sufficient strength, but when the boom B becomes long, a large lateral bending of the boom B occurs due to inertial force generated during swing braking. Power acts.

Since the strength load due to the lateral bending force becomes maximum near the boom mounting portion of the upper swing body 2, the strength is evaluated here based on the moment around the swing axis.

Specifically, the angular acceleration of the boom B during turning braking is β ', the angular acceleration of the suspended load C is βw', and the moments about the turning axis of all the components of the upper-part turning body 2 excluding the boom B are shown. If Iu, the moment Nb acting around the turning axis due to the turning is

[0034]

## EQU3 ## Nb = Iwβw '+ (Ib + Iu) β'.

The permissible condition for the transverse bending strength of the boom B is expressed by the following equation.

[0036]

## EQU00004 ## Nb / R.ltoreq..alpha.W0 By substituting equation 3 into equation 4,

[0037]

[Iwβw ′ + (Ib + Iu) β ′} / R ≦ αW0 On the other hand, from the state where there is no swing of the suspended load C and both the upper swing body 2 and the suspended load C are swinging at the angular velocity Ω0, When the upper revolving structure 2 is braked at an angular velocity β ′ (the calculation procedure will be described in detail later) with almost no vibration of the load, the relationship between the angular acceleration βw ′ of the suspended load C and the angular acceleration β ′ is as follows. Is required.

Consider a pendulum model as shown in FIG. 3 for the suspended load C. The following formula is obtained when the fielder in which a reverse inertial force acts on the suspended load C during swing acceleration / deceleration, the deflection angle of the suspended load C is θ, the rope length is Lw, and the swing speed of the boom point is V. .

[0039]

[Equation 6]

If the acceleration at the boom point is a (a <0 during braking),

[0041]

[Equation 7] V = V0 + at V0 is the turning speed of the boom point before braking (= R · Ω0)
Is.

Here, when the equation 7 is differentiated and substituted into the equation 6,

[0043]

[Equation 8]

From this differential equation

[0045]

[Equation 9] θ = A · cos ωt + B · sin ωt−a / 1

[0046]

[Equation 10]

Is obtained. In this equation, the initial condition t = 0
= 0, θ dot = 0,

[0048]

[Equation 11] θ = (a / g) · (cosωt−1)

[0049]

[Equation 12]

[0050]

[Equation 13]

Is obtained.

If these are converted into the displacement, velocity and acceleration in the turning direction of the suspended load C,

[0053]

[Equation 14]

[0054]

(Equation 15)

[0055]

[Equation 16]

It becomes

Since the acceleration (Equation 16) obtained here is the relative acceleration of the suspended load C with respect to the upper swing body 2, the absolute acceleration (acceleration with respect to the ground) aw of the suspended load C is expressed by the following equation.

[0058]

[Equation 17]

Here, since aw = βw′R and a = βR,

[0060]

(18) βw ′ = (1−cosωt) β ′ is obtained.

FIG. 4 shows the angular velocity Ω of the boom B, and the equation 1
8 shows the angular velocity Ωw of the suspended load C obtained based on 8 when the number of vibration modes (natural frequency) is 1. As shown by the broken line in the figure, the angular velocity Ωw of the suspended load C is
The vibration of one cycle is performed until the complete stop, and the angular acceleration βw ′ of the suspended load C is the angular acceleration of the boom B shown by the solid line at the time point when time t = T / 2 has elapsed since the start of braking. It is twice as large as β '.

On the other hand, when the number of vibration modes is n (≧ 2), the angular velocity Ωw of the suspended load C vibrates for n cycles during turning braking, but the angular acceleration βw ′ of the suspended load C is the minimum. The value (maximum value when taking the absolute value) is also 2β ', which theoretically does not exceed this value.

Therefore, in this embodiment, a coefficient K such that K> 2 is introduced in consideration of the safety factor, and βw '= Kβ'
The calculation is advanced as.

Substituting this equation βw '= Kβ' into the above equation 5,

[0065]

[Formula 19] {(W / g) R · Kβ ′ + (Ib + Iu) β
′} / R ≦ αW0, and the maximum angular acceleration β ′ that satisfies this equation 20 is set as the allowable angular acceleration β1.

Turning Angular Acceleration Calculating Means 18 This turning angular acceleration calculating means 18, as shown in FIG.
Basic control time calculation unit 23 and correction control time calculation unit 24
And a control value determination unit 25.

Of these, the basic control time calculation unit 23 obtains the natural frequency from the rope length Lw detected by the rope length sensor 8, and from this natural frequency, the basic value of the time required for stopping (basic control time). Find T0.

Considering the same model of the single pendulum as in FIG. 3 for the suspended load C, the differential equation of this system is as described above.

[0069]

[Equation 20]

[0070]

(21) V = V0 + at. Here, both sides of the equation 21 are differentiated with respect to the time t to obtain the equation 2
Substituting in the right side of 0 and integrating under the initial conditions (t = 0, θ = 0, θ dot = 0), the following formula is obtained.

[0071]

[Equation 22]

When this equation is expressed on the phase plane regarding θ dot / ω and θ, as shown in FIG. 5, the point A (0, −a /
A circle centering on g) and passing through the origin O (0,0) will be drawn.

The time required for one revolution of this circle, that is, the period T in which the state of the simple pendulum changes from the origin O and returns to the same state is given by T = 2π / ω, so that the turning stop control of the crane is performed. If the angular acceleration β0 is set such that it completely stops after a time nT (basic control time, where n is a natural number) from the start point (origin O), the stop control can be performed while minimizing the shake of the load.

Since ω is a constant value determined by the gravitational acceleration g and the swing radius Lw, the angular acceleration β0 is obtained by the following equation.

[0075]

[Formula 23] β0 = -Ω0 / nT = -ωΩ0 / 2nπ (n is a natural number) However, the above is due to the force (centrifugal force, Coriolis force) generated by the swivel motion, considering only the shake of the load due to the linear motion. Since the shake of the load is not taken into consideration, the shake of the load due to this turning remains as it is, only by setting the basic angular acceleration β0.

Explaining this with reference to FIGS. 7 and 8, both figures show the result of the simulation conducted by the inventor. Rope length Lw: 20 m (FIG. 7) and 10 m (FIG. 8) Boom length Lb: 30 m Boom angle: 45 ° Swing speed: 2 rpm Control time (basic control time): 8.97se in the case of FIG.
c, 6.324 sec in the case of FIG. 8 Basic angular acceleration β0: 0.023 rad / se in the case of FIG.
c. In the case of Fig. 8, braking was started from the state without load shake under the condition of 0.033 rad / sec.

In the figure, O is the origin (braking start point) where the position (displacement amount) and speed of the suspended load C are both 0, and D is the suspended load C.
In the case where the load shake occurs only by the linear movement, the suspended load C returns to the origin O according to the ideal circle by performing the above basic control. , It stops at the same time as the revolving structure stops.

On the other hand, in the simulation including the swing of the load due to the turning, the trajectory of the suspended load C on the phase plane greatly deviates from the ideal circle D due to the swing of the turning motion only by the above basic control. Becomes

The thick line in the figure shows the movement of the suspended load C when the revolving structure 2 is stopped. In this simulation, since a damping term such as friction is not included, the movement is continued and a circle is drawn. .

Therefore, in the correction control time calculation unit 24, the basic control time T0 obtained from the natural frequency determined by the rope length Lw is multiplied by the correction coefficient G in consideration of the shake of the load caused by the turning motion to perform the correction control. Find the time T1.

Then, in the control value determination unit 25, the turning angle for stop control is based on the correction control time T1 and the boom turning speed (obtained from the angular speed Ω0 of the boom B detected by the angular speed sensor 9) V. Calculate the acceleration β.

The correction coefficient G is obtained by simulation and is stored as a mathematical expression or a table in relation to the turning speed V of the boom B.

FIG. 6 shows a case where the rope length Lw is 10 m and
Boom angle φ is 45 ° and 60 ° in case of 0 m
As an example, the results of the simulation
It was found that the boom angle φ and the boom length Lb do not affect the correction coefficient G.

FIG. 9 shows a simulation result of the turning stop performed by the turning angular acceleration β thus obtained.
Shown in 10.

The conditions of this simulation are the same as those of FIG. 9 in FIG. 9 and the same as those of FIG. 8 in FIG.

As a result, as is clear from the comparison of the figures,
The trajectory of the suspended load C on the phase plane approaches the ideal circle D, and the suspended load C approaches the origin O while the revolving structure 2 is stopped, and the final shake becomes small.

On the other hand, the control value determination unit 25 determines the turning angular acceleration for braking and stopping while minimizing the shake of the load within the range of the lateral bending strength condition of the boom B, that is, | β | ≦ β1. Determine β.

Braking torque calculating means 19 and suspended load angular acceleration calculating means 21 These means 19 and 21 calculate the torque required to brake the upper revolving structure 2 at the turning angular acceleration β.

This torque calculation procedure will be described with reference to the flowchart of FIG.

First, the braking torque calculating means 19 calculates the braking torque Ts required to brake the upper revolving superstructure 2 with the turning angular acceleration β (step S1). The upper revolving structure braking torque Ts is calculated by the following equation.

[0091]

Ts = | (Ib + Iu) β | On the other hand, the suspended load angular acceleration calculation means 21 calculates the actual angular acceleration βw of the suspended load C when braking at the turning angular acceleration β (step S2). The formula for obtaining the suspended load angular acceleration βw is the same as the above-mentioned formula 18,

[0092]

[Expression 25] βw = (1-cosωt) β

Next, the braking torque calculating means 19 calculates the braking torque Tw required to brake the suspended load C based on the suspended load angular acceleration βw (step S3). This suspended load braking torque Tw is calculated by the following equation.

[0094]

Tw = | (W / g) R ² βw | Further, the sum of the upper swing body braking torque Ts and the suspended load braking torque Tw is calculated as the total braking torque Tt (step S
4) Output to the motor pressure control means 20.

Motor Pressure Control Means 20 This means 20 sets the braking side pressure Pb of the swing hydraulic motor corresponding to the total braking torque Tt, and this braking side pressure Pb.
The control signal is output based on the.

In this embodiment, the total braking torque Tt
Between the hydraulic pressure and the differential pressure ΔP of the hydraulic motor has a relationship shown by the solid line in FIG. 12, and is expressed as follows.

I) -When ΔP0 ≦ ΔP <ΔP1

[0098]

[Equation 27]

Ii) When ΔP ≧ ΔP1

[0100]

[Equation 28]

The motor differential pressure ΔP1 indicates the value of ΔP at the intersection of the straight line expressed by the equation 27 and the straight line expressed by the equation 28.

Therefore, by substituting the total braking torque Tt into the equation 27 or the equation 28, the differential pressure ΔP of the hydraulic motor for obtaining the braking torque Tt can be obtained.

Further, when the driving side pressure of the hydraulic motor is Pa, the braking side pressure Pb of the hydraulic motor can be obtained by the following equation.

Pb = Pa + ΔP The above-described operations of steps S2 to S5 are executed at a constant cycle until the turning stop is completed (step S6), so that the swing of the load during turning braking is taken into consideration and the accuracy is high. The swing stop control can be realized, and the upper swing body 2 can be stopped with almost no vibration of the suspended load C.

Second Embodiment (FIGS. 14 to 20) Explaining only the differences from the first embodiment, in the second embodiment, the initial load which is the swing of the suspended load at the start of control (braking) It is configured to perform control in consideration of shake.

That is, a shake angle sensor (for example, a CCD camera or a gyroscope can be used) 23 for detecting the shake angle θ of the initial shake of the load, and the shake angle θ detected by the shake angle sensor 23 are used. A shake direction calculating means 24 is provided for obtaining the shake direction d of the load (for example, the shake direction is obtained by the difference between the shake angle θ at the time of the previous detection and the shake angle θ at the time of this time detection), and information on the shake angle θ and the shake direction d of these suspended loads Is inputted to the turning angular acceleration calculating means 18 '.

As shown in FIG. 15, the turning angular acceleration calculating means 18 'has the same basic control time calculating unit 23 as that used in the first embodiment and both primary and secondary correction control time calculating units 24a and 24b. And a control value determination unit 25 '.

The first correction control time calculation unit 24a, like the correction control time calculation unit 24 of the first embodiment, has the basic control time T0 calculated by the basic control time calculation unit 23, and the load caused by the turning motion. The primary correction control time T1 is obtained by multiplying the correction coefficient (primary correction coefficient) G in consideration of the shake.

The secondary correction control time calculating section 24b further multiplies the primary correction control time T1 by a secondary correction coefficient H which is determined according to the initial load shake state (the shake angle θ and the shake direction d). Next correction control time T2 is calculated.

The secondary correction coefficient H is a numerical value of 1.0 or less divided into four regions I, II, III, IV classified by the initial deflection angle θ and the deflection direction d by simulation as shown in FIG. Is determined in advance and stored.

In this case, the secondary correction coefficient H may be set as a total of four kinds of values by setting a representative value for each of the two regions I to IV, or in order to further improve the accuracy. It may be stored as a function of the deflection angle θ for both regions.

In FIG. 16, Bt is the tip of the boom, and the neutral line L vertically lowered from the boom tip Bt is used as a reference.
When the suspended load W is located on the side opposite to the turning direction and swings away from the neutral line L, the region I is defined. When the suspended load W is located on the same side as the region I and swings toward the neutral line L. Region II, the region on the turning side of the neutral line L that swings toward the neutral line L is region III, and the region on the same side as this that swings away from the neutral line L is region IV. There is.

The control value determination unit 25 'determines the turning angular acceleration β for the stop control based on the secondary correction control time T2 calculated by the secondary correction control time calculation unit 24b and the boom turning speed V.

17 to 20 show comparison results of control simulations according to the first embodiment and the second embodiment.

FIGS. 17 and 18 show the case where the initial shake is in the area II. FIG. 17 shows the first embodiment and FIG. 18 shows the second embodiment (secondary correction coefficient H = 0.92).

On the other hand, FIGS. 19 and 20 show the case in the area IV, which is according to the first embodiment in FIG. 19 and the second embodiment (secondary correction coefficient H = 0.736) in FIG.

The conditions for this simulation were a boom length of 30 m, a boom angle of 45 °, a rope length of 10 m, and a turning speed of 2 rpm.

As a result, in the comparison between FIGS. 17 and 18, the residual shake of the first embodiment was 0.0212 rad, while the residual shake of the second embodiment was 0.02 rad.
It became 0184 rad.

Further, in the comparison between FIGS. 19 and 20, the residual shake of the first embodiment was 0.0253 rad, whereas the residual shake of the second embodiment was 0.0081 rad.
Therefore, in any case, according to the second embodiment, it is possible to suppress the influence of the initial shake of the load and improve the control accuracy as compared with the case according to the first embodiment.

By the way, in the second embodiment, the shake direction d is calculated based on the shake angle θ detected by the shake angle sensor 23.
However, it is also possible to detect the shake speed as a plus-direction speed / minus-direction speed by the speed sensor and obtain the shake direction.

[0121]

As described above, according to the first and third aspects of the invention, the basic control time required to stop the revolving structure is obtained from the natural frequency of the suspended load obtained from the rope length, and the basic control is performed. The correction control time is calculated by multiplying the time by a correction coefficient that is determined in advance as a coefficient in consideration of the swing of the suspended load due to the turning motion in relation to the turning speed, and the braking torque is calculated based on this correction control time. It is possible to deal with load shake including load shake due to exercise.

That is, it is possible to realize highly accurate stop control that minimizes the load shake remaining after the turning stop.

Further, according to the inventions of claims 2 and 4,
The runout state of the suspended load at the start of control is detected, and the above-mentioned correction control time (first-order correction control time) is further multiplied by the secondary correction coefficient determined according to the initial load-running state (runout angle and runout direction). The secondary correction control time is calculated using this, and the braking torque is calculated based on this, so even if there is an initial load shake,
It is possible to realize more accurate stop control in which the residual load shake is minimized.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a turning stop control device according to a first embodiment of the present invention.

FIG. 2 is a block configuration diagram showing details of a turning angular acceleration calculating means in the device.

FIG. 3 is an explanatory view showing a motion of a suspended load as a pendulum.

FIG. 4 is a graph showing characteristics of changes in the angular velocity of a suspended load and the angular velocity of a boom.

FIG. 5 is a graph showing expressions regarding a deflection angle and a deflection velocity of a suspended load in a phase space.

FIG. 6 is a graph showing a relationship between a boom turning speed and a correction coefficient obtained by simulation.

FIG. 7 is an explanatory diagram showing the movement of a suspended load on the phase plane before correction by the device of the first embodiment.

FIG. 8 is an explanatory diagram showing the movement of a suspended load before correction on the phase plane under a condition different from that of FIG. 7 according to the apparatus of the first embodiment.

FIG. 9 is an explanatory diagram showing the movement of the suspended load after correction on the phase plane.

FIG. 10 is an explanatory diagram showing the movement of the suspended load after correction on the phase plane under a condition different from that of FIG. 9;

FIG. 11 is a flowchart for explaining a braking torque calculation operation by the braking torque calculation means in the first embodiment device.

FIG. 12 is a graph showing the relationship between the differential pressure of the hydraulic motor and the braking torque.

FIG. 13 is a schematic configuration diagram of a swing crane to which the present invention is applied.

FIG. 14 is a block configuration diagram of a turning stop control device according to a second embodiment of the present invention.

FIG. 15 is a block configuration diagram showing details of a turning angular acceleration calculating means in the device.

FIG. 16 is a diagram showing four areas divided in advance in order to determine a secondary correction coefficient in the same means.

FIG. 17 is an explanatory diagram showing the movement of the suspended load on the phase plane by the device of the first embodiment without considering the initial shake of the load.

FIG. 18 is an explanatory diagram showing the movement of the suspended load on the phase plane by the device of the second embodiment under the same conditions as in FIG. 17;

FIG. 19 is an explanatory view showing the movement of the suspended load on the phase plane under the conditions different from those of FIGS. 17 and 18;

FIG. 20 is an explanatory diagram showing the movement of the suspended load on the phase plane of the suspended load by the device of the second embodiment under the same conditions as in FIG. 19;

[Explanation of symbols]

2 Upper Revolving B B Boom 4 Suspended Rope 8 Rope Length Sensor (Rope Length Detection Means) 9 Angular Velocity Sensor (Boom Rotation Speed Detection Means) 18 Turning Angular Acceleration Calculating Means 23 Basic Control Time Calculating Unit Constituting Turning Angular Acceleration Calculating Means 24 Same correction control time calculation unit 25 Same control value determination unit 19 Braking torque calculation unit 20 Motor pressure control unit 18 ′ Turning angular acceleration calculation unit 24a Primary correction control time calculation unit 24b Secondary correction control time calculation unit 25 ′ Control in the same means Value determination unit 23 Deflection angle sensor 24 Deflection direction calculation means

Claims (4)

[Claims] 1. A natural frequency of a suspended load is obtained from the length of a suspension rope suspended from a boom point, and a basic control time required to stop a revolving structure is obtained from this natural frequency. The control time is calculated by multiplying the control time by a correction coefficient that is determined in advance as a coefficient that takes into consideration the swing of the suspended load due to the turning motion in relation to the turning speed, and the correction control time is calculated based on this correction control time and the turning speed of the turning body. While calculating the turning angular acceleration to stop the body,
A method of controlling turning stop of a crane, characterized in that a braking torque for obtaining the turning angular acceleration is calculated, and the turning body is braked based on the braking torque. 2. The natural frequency of the suspended load is obtained from the length of the suspension rope suspended from the boom point, and the basic control time required to stop the revolving structure is obtained from this natural frequency. The control time is multiplied by a primary correction coefficient that is determined in advance as a coefficient that takes into consideration the swing of the suspended load due to the turning motion in relation to the turning speed, to obtain the primary correction control time, and this primary correction control time is calculated at the start of control. The secondary correction control time is calculated by multiplying the secondary correction coefficient that is determined according to the swing state of the suspended load, and the swing angle for stopping the swing structure is calculated from this secondary correction control time and the swing speed of the swing structure. A method of controlling the turning stop of a crane, characterized in that the acceleration is calculated, a braking torque for obtaining the turning angular acceleration is calculated, and the turning structure is braked based on the braking torque. 3. A rope length detecting means for detecting a length of a suspension rope suspended from a boom point, a swing speed detecting means for detecting a swing speed of a boom, and a swing angular acceleration for stopping a swing structure. A turning angular acceleration calculating means for calculating, a braking torque calculating means for calculating a braking torque of the revolving structure based on the calculated turning angular acceleration, and a motor for controlling the pressure of the turning motor based on the calculated braking torque. The swing angular acceleration calculating means includes a pressure control means, obtains the natural frequency of the suspended load from the rope length detected by the rope length detecting means, and stops the revolving structure from the natural frequency. The basic control time required for the A turning stop control device for a crane, characterized in that it is configured to obtain a correction control time for calculating the turning angular acceleration by multiplying by a coefficient. 4. A rope length detecting means for detecting a length of a hanging rope suspended from a boom point, a swing speed detecting means for detecting a swing speed of a boom, and a swinging state of a suspended load at a control start time. Deflection state detecting means for detecting, swing angular acceleration calculating means for calculating swing angular acceleration for stopping the swing body, and braking torque calculating means for calculating braking torque of the swing body based on the calculated swing angular acceleration. And a motor pressure control means for controlling the pressure of the swing motor on the basis of the calculated braking torque, wherein the swing angular acceleration calculation means calculates the suspended load from the rope length detected by the rope length detection means. In addition to obtaining the natural frequency, the basic control time required to stop the revolving structure is obtained from this natural frequency, and the swing of the suspended load due to the swing motion is calculated in this basic control time. The primary correction coefficient determined in advance in relation to the turning speed is multiplied as a coefficient considered to obtain the primary correction control time for calculating the turning angular acceleration, and the primary correction control time is further calculated by the shake state detecting means. A turning stop control device for a crane, characterized in that it is configured to obtain a secondary correction control time by multiplying by a secondary correction coefficient determined according to the detected swinging state of the suspended load at the start of control.