JP3087616B2 - Sway control method for crane suspended load - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension control method for a suspended load of a suspended rope crane.

[0002]

2. Description of the Related Art In general, in crane operation, it is desired to shorten a so-called cycle time from lifting a load, traveling laterally to unloading the load, and to increase the cargo handling efficiency as much as possible. At this time, if a residual deflection of the load occurs at the end of the lateral traveling, the suspended load cannot be unloaded for safety reasons. Therefore, it is necessary to wait until the load deflection falls within an allowable range.
This waiting time increases the cycle time and reduces the cargo handling efficiency. In particular, in manned cranes, steady rest control based on the driver's intuition and experience is performed,
It took a considerable amount of time to become skilled.

On the other hand, there are two types of steady rest control mechanisms in an unmanned crane, a mechanical control mechanism and an electric control mechanism. In the former mechanical control mechanism, since a movable portion such as a crane hook is structurally fixed, no shake is generated in principle, and complete swing prevention control is possible. However, the latter electrical control mechanism is often more cost-effective. Further, in the mechanical control mechanism, it is necessary to hoist the suspended load to the highest position before the lateral traveling, which is disadvantageous in the cycle time. From this point,
There is an increasing need for cranes with an electric steady rest.

Conventionally, in a crane operation control method provided with an electric steady rest control mechanism, an acceleration / deceleration time related to a swing cycle of a suspended load is set, and a speed pattern control that does not leave a shake due to a physical law is adopted. Often. The speed pattern control known at present is roughly classified into a plurality of time sections in which the crane acceleration during operation is constant as shown in FIG. 5A, and a crane speed pattern as shown in FIG. 5B. (Japanese Patent Publication No. 61-031032) and a method in which the crane acceleration is continuously changed as shown in FIG. 6A and the crane speed pattern is changed as shown in FIG. 6B. Method of controlling so as to draw a smooth continuous curve (JP-A-6-305686)
Divided into

[0005]

By the way, from the viewpoint of cycle time, it is necessary to use the maximum acceleration of the crane effectively and accelerate the crane to the maximum speed. In that respect, the former speed pattern based on the polygonal line is superior. However, the crane is not a rigid body but has a girder, a torsion of a drive shaft, a play of a speed reducer, and the like. In order to prevent deterioration of control performance due to these, it is desirable to adopt a speed pattern based on a continuous curve.

The present invention has been devised in view of such a problem, and has a steady velocity pattern that draws a smooth continuous curve, but uses the maximum acceleration given by the specifications of the electric motor and mechanical constraints to obtain the maximum velocity. It is an object of the present invention to provide a steady rest speed pattern that can accelerate and decelerate quickly.

[0007]

According to the present invention, there is provided a method for controlling the suspension of a suspended load of a crane according to the present invention. A first step of linearly increasing or decreasing the acceleration η ₁ from the zero value over a time T ₁ to the acceleration η ₁ , and the acceleration η for a time T ₂ obtained by subtracting the time T ₁ from a half of the swing cycle of the suspended load. a second step of holding _1, over the time T ₁ the same time, a third step of linearly increasing or decreasing from the acceleration eta ₁ to acceleration eta ₂ is twice the acceleration of the acceleration eta ₁ ,
A fourth step of holding the acceleration η ₂ for a predetermined time T _3, and a fifth step of linearly decreasing or increasing the acceleration η ₂ to the acceleration η ₁ over the same time as the time T ₁ .
A step, a sixth step of holding only an acceleration eta ₁ wherein the time T ₂ the same time, the acceleration eta ₁ over the time T ₁ and the time
And a seventh step of linearly decreasing or increasing from zero to a zero value.

With the above-described structure, the speed of the crane can be smoothly increased and decreased, and the deterioration of the control performance due to the torsion of the girder and the drive shaft and the play of the speed reducer can be prevented.

Further, the acceleration η ₂ is set to the maximum acceleration of traveling given by the specifications of the electric motor used for the crane, mechanical restrictions, and the like.

Further, when the seventh step is an acceleration step of the crane, the speed of the crane at the end of the seventh step is determined based on the specifications of the electric motor used in the crane, mechanical restrictions, and the like. It said to be the maximum speed of the is obtained by setting the predetermined time T _3.

[0011]

FIG. 1 is a block diagram of an automatic control device for a crane used in an embodiment of the present invention. In the figure, reference numeral 1 denotes a crane, and a rope 4
It travels in the x-direction while suspending the suspended load 3 attached to the lower end of the vehicle. The traveling of the crane 1 is controlled by the crane position detecting device 11,
Rope length detector 12, runout cycle calculator 13, crane movement target commander 14, speed pattern generator 15,
A motor control device 16 and a speed control motor 17;

The crane position detecting device 11 is a device for detecting a position of the crane 1 traveling on the rail 2 from a starting point. The crane position detecting device 11 can detect the traveling position of the crane 1 from the amount of rotation of the wheels of the crane 1 and the like. It has become. The rope length detection device 12 is a device for detecting the length of the rope 4 during traveling, and detects the length of the rope 4 from the rotation amount of a winding motor of the rope 4 and the like. The swing cycle calculation device 13 is a device that calculates the swing cycle of the suspended load 3 based on the detection signal from the rope length detection device 12. The swing cycle calculating device 13 mainly calculates the swing cycle based on the hanging rope information from the rope length detecting device 12. In some cases, the swing cycle calculating apparatus 13 calculates the swing cycle in consideration of auxiliary information such as the mass of the suspended load. Calculate.

The speed pattern generator 15 generates a speed pattern to be given to the crane 1 based on a calculation signal from the shake period calculator 13 and a signal from the crane movement target command device 14. The motor control device 16 is configured by a minor control loop for realizing an operation speed command externally given to the speed control motor 17. That is, the speed control motor 17 is automatically controlled so as to be a speed command value from the motor control device 16.

The automatic control device as described above implements the crane operation control method according to the present embodiment.
In the present embodiment, as shown in FIG. 2, the mass of the suspended load 3 is m, the swing angle of the suspended load 3 is θ, the length of the rope 4 is L, the position of the crane 1 is x, and the crane 1 Rail 2
It is assumed that the vehicle is traveling at an acceleration d ² x / dt ² (hereinafter referred to as η). At this time, assuming that the swing of the suspended load 3 is not large, the equation of motion of the suspended load 3 is as follows. Lm (d ² θ / dt ² ) = − mgθ−mη (1) By removing m from the above equation, L (d ² θ / dt ² ) = − gθ−η (...) 2) or d ² θ / dt ² = −ω ² θ−η / L (3) (g is the gravitational acceleration and ω ² = g / L). Will be described using the above equation of motion.

FIG. 3 is a time chart showing the crane acceleration pattern applied in the present embodiment, and the resulting crane speed and suspended load swing angle. FIG. 4 is a phase locus diagram of the deflection angle θ and its angular velocity. In the present embodiment, the speed of the crane is smoothly changed without sudden change by suspending the load 3 and continuously changing the acceleration of the crane 1 traveling on the rail 2. Therefore, the crane acceleration is changed as shown in FIG.
As shown in (1), the control is performed so that the pattern includes an acceleration section I in which the speed increases, a constant speed section II in which the speed is constant, and a deceleration section III in which the speed decreases.
In FIG. 3, the upper side (positive direction) of the time axis t indicates the traveling direction of the crane 1, and the lower side (negative direction) indicates the direction opposite to the traveling direction.

Hereinafter, the crane speed, acceleration, and swing angle of the suspended load will be specifically described for each section. (1) Acceleration section I In this section, as shown in FIG.
And a constant velocity connecting portion C. The running start portion A is further subdivided into three sections: section A ₁ , section A ₂ and section A ₃ . In the section A ₁ , the acceleration is changed from a zero value to a half of the maximum acceleration η _max at an arbitrary time T ₁ , ie, ( _1/1 ).
2) A section in which the rate is increased at a constant gradient up to η _max . The section A ₂ is a time T ₂ determined from the shake periods T and T _1.
= T / 2−T ₁ is a section in which the acceleration is held at (１ ／) η _max . Further, the section A ₃ is (1/1 / T ₁₎
2) it is an interval to increase the acceleration at a constant gradient from eta _max to eta _max.

The acceleration section B is a section where the acceleration of the crane is constant, and this section is not subdivided. The constant velocity connecting portion C is subdivided into three sections, a section C ₁ , a section C _2, and a section C ₃ , similarly to the running start part A. Section C ₁ is
Acceleration at any time T ₁ from the maximum acceleration η _max (1 /
2) A section in which the value is decreased at a constant gradient up to η _max . The section C ₂ is a time T ₂ determined from the shake periods T and T _1.
= T / 2−T ₁ is a section in which the acceleration is held at (１ ／) η _max . Further, the section C ₃ is (1/1 / T ₁₎
2) A section in which the acceleration is reduced at a constant gradient from η _max to a zero value.

[0018] First of all, the speed of the crane in the section A _1,
The acceleration and the swing angle of the suspended load will be described. The acceleration η in the section A ₁ from the above setting conditions, represented by the following equation as a function of time t. _{η = (1/2) η max t} / T 1 ····· (4) By integrating this equation (4), the speed v of the crane 1 in the section A ₁ becomes the following equation (5) . v = (1/4) η _max t ² / T ₁ (5) As is apparent from the equation (5), in this section, the speed v of the crane 1 increases quadratically. This speed curve draws a smooth curve as shown in FIG.

At this time, the swing angle θ and the swing angular velocity dθ / dt of the suspended load 3 are set as θ (0) =
Taking into account 0 and (dθ / dt) (0) = 0, from the above equation (3), they are expressed by the following equations (6) and (7), respectively. θ = η _max (sin (ωt) −ωt) / (2T ₁ gω) (6) dθ / dt = η _max (cos (ωt) -1) / (2T ₁ g) (7) Therefore, θ at t = T ₁ which is the end of section A ₁
And dθ / dt (hereinafter referred to as φ) are given by the following (8) and (9)
It is the value represented by the formula. θ ₁ = η _max (sin (ωT ₁ ) −ωT ₁ ) / (2T ₁ gω) (8) φ ₁ = η _max (cos (ωT ₁ ) -1) / (2T ₁ g) ... (9) as a result, the locus on the phase plane of the point in the section _{a 1 (φ / ω, θ} ) , as shown in FIG. 4, from the origin O P1 (phi ₁
/ Ω, θ ₁ ). That is, the swing angle θ of the suspended load 3 gradually increases from zero in the direction opposite to the traveling direction of the crane 1 as shown by the two-dot chain line in FIG. 3C and FIG.

Next, hold the acceleration (1/2) η _max at the end of the section A ₂ in the section A ₁ by _{T 2 = (1/2) T-} T 1 hour. That is, in the section A ₂ eta = (1/2) set eta _max · · · · · (10). As a result, the crane speed v becomes equal to the section A ₂
Taking into account the initial condition, the following expression (11) is obtained, and FIG.
It increases linearly as shown in FIG. v = (1/2) η _max t− (1/4) η _max T ₁ (11)

Further, the deflection angle theta of suspended load in this case, the swing angular velocity phi, the initial conditions theta ₁ of the section A _2, considering the _{φ 1, θ = η max (} sin (ωt) + sin (ωT 1 −ωt) −ωT ₁ ) / (2T ₁ gω) (12) φ = η _max (cos (ωt) −cos (ωt−ωT ₁ ) / (2T ₁ g) (13) . the value of theta and φ at the end of the section a _2, by substituting _{t = T 1 + T 2 =} T / 2 in equation (12) (13), can be obtained as follows. theta ₂ = −η _max (sin (ωT ₂ ) + ωT ₁ ) / (2T ₁ gω) · (14) φ ₂ = −η _max (1 + cos (ωT ₂ )) / (2T ₁ g) (15) locus of the points in the section _{a 2 (φ / ω, θ} ) from P1 in FIG. _{4 P2 (φ 2 / ω,} θ 2) to move to.

[0022] In section A _3, sets the acceleration _{η = η max (t-T} 1 -T 2) / (2T 1) + η max / 2 and ... (16). As a result, the speed of the crane 1 becomes
7) _{v = η max (t-T} 1 -T 2) 2 / (4T 1) + η max (t-T 1/2) / 2 ····· (17) As is apparent from the equation (17), In this section, the speed v of the crane 1 increases quadratically, and this speed curve draws a smooth curve as shown in FIG.

At this time, the swing angle θ and the swing angular velocity φ of the suspended load 3 are given by θ = η _max (sin (ωt + ωT ₂ ) −ω (t−T ₂ )) / (2T) in consideration of θ ₂ and φ _{2. 1} g [Omega]) becomes _{··· (18) φ = η max} (cos (ωt + ωT 2) -1) / (2T 1 g) ··· (19).

The values of θ and φ at the end of the section A ₃ can be obtained as follows by substituting t = T ₁ + T ₂ + T ₁ into the above equations (18) and (19). _{θ 3 = -η max / g ·····} (20) φ 3 = 0 ····· (21) i.e., the locus of the point in the interval _{A 3 (φ / ω, θ} ) , in FIG. 4 P2 To P3 (φ ₃ / ω, θ ₃ ). Point P3 is a static balancing position determined by the maximum acceleration η _max .

Next, the operation of the acceleration section B will be described. In the accelerating section B, the acceleration η of the crane 1 is held at the maximum acceleration η _max . The holding time T ₃ is obtained. As a condition for determining the holding time T _3, the acceleration of the constant velocity joint portions C is changed in the reverse pattern of the running start portion A, and the speed of the crane 1 at the end of the acceleration section I becomes the maximum speed v _max Calculation taking into account that That placed and is equal to v _max area surrounded by the acceleration diagram and a time axis in the acceleration section I in FIG. 3 (a),
By rearranging this for T ₃ , the following equation (2)
It is required as in 2). T ₃ = v _max / η _max -T ₁ -T / 2 (22)

Since the acceleration is maintained at η _max during the time T ₃ , the speed of the crane 1 increases linearly as shown in the following equation (23). v = eta _max The _{(t-T 1 -T 2/} 2) ····· (23), in this interval, the load 3 hanging from the acceleration constant is held at a static equilibrium state, The shake angle θ and the shake angular velocity φ are kept as they are in the expressions (20) and (21). Therefore, the point (φ / ω, θ) in FIG.
In this section will stagnate at the position of P3.

In the constant velocity connecting portion C, the acceleration pattern is changed in a pattern opposite to the portion A in which the vehicle starts running. That is, the crane acceleration is reduced from η _max to (１ ／) η _max at a constant gradient in the above T ₁ time, and thereafter, the acceleration is kept at (１ ／) η _max for the above T ₂ time and further reduced to zero value. the acceleration is reduced at a constant gradient in the time T _1. At this time, assuming that the deflection angle condition at the end of the constant velocity connection portion is θ = 0 and φ = 0, the equation (3) is solved in the reverse time, whereby the deflection angles θ ₄ and φ at the start of the constant velocity connection portion are obtained. ₄ (20), is confirmed that a value of (21). That is, the acceleration section I
After completion, the shake angle θ and the shake angular velocity φ are as follows: θ = 0 (24) φ = 0 (25) That is, the suspended load 3 is stopped in a state of being suspended in the vertical direction.

(2) Constant Speed Section II In the constant speed section II, the acceleration η = 0, and the crane 1 runs at a constant speed (v _max ). Therefore, since the suspended load 3 is set to the state shown by the formulas (24) and (25) as the initial condition, the suspended load 3 is suspended in the vertically suspended state without swinging. The traveling time in the constant speed section II can be arbitrarily set in relation to the destination.

(3) Regarding the deceleration section III Since the acceleration in the deceleration section III is the reverse of the sign of the acceleration in the acceleration section I, only the signs of the deflection angle θ and the deflection angular velocity φ are reversed. After the end of the deceleration, both the shake angle θ and the shake angular velocity φ become zero values.

The maximum acceleration η _max and the maximum speed v
_max can be set freely within the range of the capability of the speed control motor 17.

According to the present embodiment, since the crane acceleration changes continuously and the crane speed pattern draws a smooth continuous curve, the control performance is prevented from deteriorating due to the torsion of the girder and the drive shaft and the play of the speed reducer. be able to. In addition, the cycle time can be reduced by performing acceleration / deceleration in a shorter time as compared with the conventional continuous curve speed pattern.

[0032]

The present embodiment and the conventional method (Japanese Patent Laid-Open No.
No. 5686) is specifically compared. η _max = 0.5 (m / s ² ) v _max = 3.0 (m / s) T = 5.0 (sec) T ₁ = T / 4 = 1.25 (sec) In the conventional method, The required time t _old of the acceleration section I or the deceleration section III is t _old = T + v _max / η _max = 11.0 (sec), whereas in the method according to the present invention, t _new = T ₁ + T / 2 + v _max / η _max = 9.75 (s
ec). The fact that the required time in the acceleration section I can be shortened means that the maximum speed v _max can be reached quickly, and the fact that the required time in the deceleration section III can be reduced means that the time required to travel at the maximum speed v _max becomes longer. Means that you can. Therefore, the cycle time can be reduced.

[0033]

As described above, according to the method of controlling the steady movement of a crane hanging load according to the present invention, the crane speed can be smoothly increased and decreased, and the control by the girder, the drive shaft torsion and the play of the speed reducer can be performed. The performance can be prevented from being deteriorated, and the cycle time can be reduced by performing acceleration / deceleration in a shorter time as compared with the conventional continuous curve speed pattern.

[Brief description of the drawings]

FIG. 1 is a block diagram of a crane automatic control device applied to a crane operation control method according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating an operation of the crane applied to the embodiment.

FIG. 3 is a time chart showing physical quantities controlled by the crane operation control method according to the embodiment, and FIG.
Shows the crane acceleration, FIG. 3B shows the crane speed, and FIG. 3C shows the swing angle of the suspended load.

FIG. 4 is a phase plane locus diagram of a deflection angle and its angular velocity.

FIG. 5 is a time chart showing a conventional crane control method, and FIG. 5 (a) shows crane acceleration;
5B shows the crane speed, and FIG. 5C shows the swing angle of the suspended load.

FIG. 6 is a time chart showing a conventional crane control method, and FIG. 6 (a) shows crane acceleration;
6B shows the crane speed, and FIG. 6C shows the swing angle of the suspended load.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Crane 2 Rail 3 Suspended load 4 Rope A Running part B Acceleration part C Constant velocity connection part

────────────────────────────────────────────────── ─── Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B66C 13 / 06,13 / 22

Claims (3)

(57) [Claims] 1. An operation control method of a suspended crane for stopping swing of a suspended load, wherein the acceleration control pattern of the suspended crane is linearly increased from a zero value to an acceleration η ₁ over a time T _1. A second step of maintaining the acceleration η ₁ for a time T ₂ obtained by subtracting the time T ₁ from a half of the swing cycle of the suspended load.
A step, over the time T ₁ the same time, a third step of linearly increasing or decreasing from the acceleration eta ₁ to acceleration eta ₂ is twice the acceleration of the acceleration eta _1, the acceleration eta ₂ a fourth step of holding a predetermined time T _3, a fifth step of the to linearly decreased or increased to the acceleration eta ₁ from the acceleration eta ₂ over the time T ₁ the same time, and the time T ₂ the A sixth step of holding the acceleration η ₁ for a time, and a seventh step of linearly decreasing or increasing the acceleration η ₁ to a zero value over the same time as the time T _1. Characteristic method of controlling steadying of suspended load on a crane. 2. The steady rest of a crane hanging load according to claim 1, wherein the acceleration η ₂ is set to a maximum acceleration of traveling given by specifications of an electric motor used for the crane, mechanical restrictions, and the like. Control method. 3. In the case where the seventh step is an acceleration step of the crane, the speed of the crane at the end of the seventh step is given by specifications of a motor used in the crane, mechanical restrictions, and the like. claim 1, wherein the predetermined time T ₃ that was set at the maximum speed of travel
The method for controlling the steady rest of the suspended load of the crane described above.