JPH0940362A - Clamping control method of hanging cargo of crane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out the acceleration and the deceleration to the maximum speed rapidly by specifying the acceleration time variation pattern in an acceleration section and a deceleration section. SOLUTION: A speed pattern generating device 15 generates a speed pattern given to a crain 1 depending on the operated signal from a deflection cycle operation device 13, and the signal form a crain moving target instruction device 14. The acceleration time variation pattern in an acceleration section and a deceleration section consists of the first section where the acceleration is changed according to the first trapezoidal pattern, the second section to maintain the acceleration zero, and the third section where the acceleration is changed according to the second trapezoidal pattern. Consequently, the increase and decrease of the speed of the crain 1 is made smooth, and the deterioration of the control function owing to the deflections of a garder and a drive shaft, the rattle of a speed reducer, and the like, can be prevented.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Generally, in crane operation, it is desired to shorten the so-called cycle time for hoisting a load, traveling laterally, and unloading the load to improve the cargo handling efficiency as much as possible. At this time, if the residual vibration of the load occurs at the end of the lateral traveling, it is not possible to unload the suspended load for safety. Therefore, it is necessary to wait until the vibration of the load falls within the allowable range.
This waiting time increases the cycle time and causes a decrease in cargo handling efficiency. Especially in manned cranes, steady rest control is performed based on the driver's intuition and experience.
It took quite a long time to become skilled.

On the other hand, there are two types of steady rest control mechanisms for unmanned cranes, a mechanical control mechanism and an electrical control mechanism. In the former mechanical control mechanism, the movable part such as the crane hook is structurally fixed, so in principle, no shake occurs and complete steady control is possible. However, the latter electric control mechanism is often more advantageous in terms of cost. In addition, the mechanical control mechanism requires the hoisted load to be wound up to the highest position before lateral traveling, which is disadvantageous in cycle time. From this point,
The need for cranes with an electronic steady rest is increasing.

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 velocity pattern control in which a shake does not remain according to a physical law is adopted. In many cases. The currently known speed pattern control is roughly classified, as shown in FIG. 6 (a), a plurality of time intervals in which the crane acceleration during operation is constant are combined, and as shown in FIG. 6 (b), the crane speed pattern is controlled. Is controlled so that it becomes a broken line (Japanese Patent Publication No. 61-031032), and the crane acceleration is continuously changed as shown in FIG. 7 (a), and the crane speed pattern is changed as shown in FIG. 7 (b). A method of controlling so as to draw a smooth continuous curve (JP-A-6-305686)
It is divided into

[0005]

From the viewpoint of cycle time, it is necessary to effectively use the maximum acceleration of the crane to quickly accelerate to the maximum speed of the crane. Further, in the speed pattern control, the acceleration / deceleration time is restricted to the swing cycle. Therefore, the point of shortening the cycle time is how to shorten the acceleration / deceleration time especially when the shake cycle is long. On the other hand, the crane does not have a rigid body but has a girder, a twist of a drive shaft, a backlash of a speed reducer, and the like, and it is desirable to adopt a speed pattern based on a continuous curve in order to prevent deterioration of control performance due to them.

The present invention has been devised in view of the above problems, and an object thereof is to provide a steady rest speed pattern capable of quick and smooth acceleration / deceleration.

[0007]

A steadying control method for a crane suspended load according to the present invention comprises an acceleration time change pattern, an acceleration section for accelerating a crane to a predetermined speed, and the predetermined speed accelerated in the acceleration section. A constant velocity section for holding and a deceleration section for decelerating from the predetermined speed to stop the crane, and an acceleration time change pattern in the acceleration section and the deceleration section in which the acceleration changes according to a first trapezoidal pattern. Section and second to keep the acceleration at zero
It is composed of a section and a third section in which the acceleration changes according to the second trapezoidal pattern.

With the above construction, the speed of the crane can be smoothly increased and decreased, and control performance deterioration due to twisting of the girder and drive shaft, looseness of the speed reducer, etc. can be prevented.

In the first trapezoidal pattern, the step of linearly increasing or decreasing the acceleration from a zero value to a predetermined acceleration η over time T ₁ and the acceleration during the time T ₂ are the acceleration. η, and a step of linearly decreasing or increasing the acceleration from the acceleration η to a zero value over time T ₃ , and the second trapezoidal pattern is over the time T ₃ . Linearly increasing or decreasing the acceleration from a zero value to the acceleration η; holding the acceleration η for the time T ₂ ;
Multiplying by ₁ to linearly decrease or increase the acceleration from the acceleration η to a zero value.

Further, the time T ₁ is made equal to the time T ₃ , and the first trapezoidal pattern and the second trapezoidal pattern are both congruently equilateral trapezoids. By simplifying the acceleration pattern in this way, adjustment of the acceleration becomes easy.

When the swing angle and the swing angular velocity of the suspended load at the end of the first trapezoidal pattern are θ and φ, respectively, until the swing angle and the swing angular velocity reach θ and −φ, respectively. The second section in which the acceleration is kept at zero value is held.

[0012]

1 is a block diagram of an automatic control device for a crane used in an embodiment of the present invention. In the figure, 1 is a crane, and a rope 4 is mounted on a rail 2.
It is adapted to travel in the x direction while suspending the suspended load 3 attached to the lower end of the. The crane position detection device 11 controls the traveling of the crane 1.
Rope length detection device 12, swing period calculation device 13, crane movement target command device 14, speed pattern generation device 15,
A motor control device 16 and a speed control motor 17.

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

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

The crane operation control method according to the present embodiment is realized by the automatic control device as described above.
In the present embodiment, as shown in FIG. 2, the mass of the suspended load 3 is m, the deflection angle of the suspended load 3 is θ, the length of the rope 4 is L, and the position of the crane 1 is x. 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 ) = − mg θ−m η (1) Eliminating m from the above equation, L (d ² θ / dt ² ) = − g θ−η ( 2) Or, d ² θ / dt ² = −ω ² θ−η / L (3) (g is gravitational acceleration, and ω ² = g / L.) The shake of will be described using the above equation of motion.

FIG. 3 is a time chart showing a crane acceleration pattern applied in the present embodiment, and a crane speed and a suspended load deflection angle resulting therefrom. FIG. 4 is a phase plane locus diagram of the deflection angle θ and its angular velocity. In the present embodiment, the load of the crane 3 is suspended and the acceleration of the crane 1 traveling on the rail 2 is continuously changed, so that the speed of the crane is smoothly changed without a sudden change. Therefore, the crane acceleration is calculated as shown in Fig. 3 (a).
As shown in Fig. 5, the crane is configured to include an acceleration section for accelerating to a predetermined speed, a constant velocity section for maintaining a predetermined speed accelerated in the acceleration section, and a deceleration section for decelerating from the predetermined speed and stopping the crane. The acceleration time change pattern in the deceleration section includes a first section in which the acceleration changes according to a trapezoidal pattern, a second section in which the acceleration is kept at zero value, and a first section in which the acceleration changes according to a trapezoidal pattern congruent with the first section. It is composed of three sections. In addition,
In FIG. 3, the crane 1 is on the upper side (forward direction) of the time axis t.
The traveling direction is shown, and the lower side (negative direction) shows the opposite direction to the traveling direction.

The crane speed, acceleration, and swing angle of the suspended load will be specifically described for each section. For simplicity, the trapezoid of the acceleration pattern is an isosceles trapezoid, and the trapezoid has an upper base T ₂ and a lower base T ₁ + T ₂ + T ₁ . (1) Acceleration section In this section, as shown in FIG. 3 (a), up to half of the target speed due to the isosceles trapezoidal acceleration change, section 2 where a constant speed is maintained, and up to the target speed It is composed of a section 3 which is accelerated again by the acceleration change of the trapezoidal shape. In the section 1, the acceleration is further changed from zero value to the maximum acceleration η at an arbitrary time T _1.
A small section A ₁ that increases with a constant gradient up to _max , a time T ₂ = v _max / (2 which is determined from the target speed, the maximum acceleration, and T ₁
η _max ) -A small section A in which the acceleration is held at η _max by T _1.
2 , it is subdivided into small sections A ₃ that decrease from η _max to a zero value at a constant gradient in the time T ₁ . Further, in the section 3, similarly to the section ₁ , the acceleration is changed from the zero value to the maximum acceleration η _ma at the arbitrary time T _1.
x Subsection B ₁ that increases with a constant gradient, subsection B ₂ that holds the acceleration at η _max for time T _{2 and} subsection B ₃ that decreases with a constant gradient from η _max to zero in T ₁ time. .

First, the speed and acceleration of the crane and the swing angle of the suspended load in the small section A ₁ will be described. The acceleration η in the small section A ₁ is expressed by the following equation as a function of the time t from the above setting conditions. η = η _max t / T ₁ (4) By integrating this equation (4), the speed v of the crane 1 in the small section A ₁ becomes the following equation (5). v = (1/2) η _max t ² / T ₁ (5) As is clear from this equation (5), the speed v of the crane 1 increases quadratically in this section. The velocity curve draws a smooth curve as shown in FIG. 3 (b).

The deflection angle θ and the deflection angular velocity dθ / dt of the suspended load 3 at this time are θ (0) =
Considering 0 and (dθ / dt) (0) = 0, the following equations (6) and (7) are obtained from the above equation (3). θ = η _max (sin (ωt) −ωt) / (T ₁ gω) ... (6) dθ / dt = η _max {cos (ωt) -1} / (T ₁ g) ... (7) Therefore, θ and dθ / dt (hereinafter referred to as φ) at t = T ₁ which is the end of the small section A ₁ are as follows (8),
The value is expressed by the equation (9). θ ₁ = η _max {sin (ωT ₁ ) −ωT ₁ } / (T ₁ gω) (8) φ ₁ = η _max {cos (ωT ₁ ) −1} / (T ₁ g) .. (9) As a result, the locus of the point (φ / ω, θ) on the phase plane in the small section A ₁ is from the origin O to P1 (φ) as shown in FIG.
It will move up to ₁ / ω, θ ₁ ). That is, the deflection angle θ of the suspended load 3 gradually increases from a zero value in the direction opposite to the traveling direction of the crane 1, as shown by the chain double-dashed line in FIGS. 3C and 2.

Next, in the small section A ₂ , the acceleration η _max at the end of the small section A ₁ is held for T ₂ = v _max / (2η _max ) −T ₁ hours. That is, in the small section A ₂ , η = η _max (10) is set. As a result, the crane speed v is
Considering the initial condition of _2, the following formula (11) is obtained, and
It increases linearly as shown in (b). v = η _max (t−T ₁ ) + (1/2) η _max T ₁ (11)

Further, the swing angle θ and swing angular velocity φ of the suspended load at this time are θ = η _max {sin (ωt) + sin (ωT when considering θ ₁ and φ ₁ which are initial conditions of the small section A _{2. 1} −ωt) −ωT ₁ } / (T ₁ gω) (12) φ = η _max {cos (ωt) −cos (ωT ₁ −ωt}) / (T ₁ g) ・ ・ ・ (13) Becomes The values of θ and φ at the end of the small section A ₂ are t = T ₁ + T ₂ = v _max / (2
By substituting η _max ), the following can be obtained. θ ₂ = η _max {sin (ωv _max / (2 η _max )) + sin (ωT ₁ −ωv _max / (2 η _max )) − ωT ₁ } / (T ₁ gω) ··· (14) φ ₂ = η _max {cos (ωv _max / (2 η _max )) −cos (ωT ₁ −ωv _max / (2 η _max ))} / (T ₁ g) ··· (15) That is, The locus of the point (φ / ω, θ) in the small section A ₂ moves from P1 to P2 (φ ₂ / ω, θ ₂ ) in FIG.

In the small section A ₃ , the acceleration is set as η = η _max −η _max {t−v _max / (2 η _max )} / T ₁ (16). As a result, the speed of crane 1
Equation 7) is obtained. _{v = η max (t-v} max / (2 η max)) - η max {t-v max / (2 η max)} 2 / (2T 1) + v max / 2-η max T 1/2 ·· (17) As is apparent from the equation (17), the speed v of the crane 1 increases quadratically in this section, and the speed curve is smooth as shown in FIG. 3 (b). You will draw a curve.

At this time, the deflection angle θ and the deflection angular velocity φ of the suspended load 3 are θ = η _max {sin (ωt) −sin (ωt−ωT ₁ ) −sin (ωt−) considering θ ₂ and φ _2. ω v _max / (2 η _max )) + ω (t−T ₁ −v _max / (2 η _max ))} / (T ₁ g ω) (18) φ = η _max {1 + cos (ωt) −cos ( ωt−ωT ₁ ) −cos (ωt −ωv _max / (2 η _max ))} / (T ₁ g) ··· (19).

The values of θ and φ at the end of the small section A ₃ are
By substituting t = T ₁ + T ₂ + T ₁ into the above equations (18) and (19), the following can be obtained. θ ₃ = η _max {sin (ωv _max / (2η _max ) + ωT ₁ ) −sin (ωv _max / (2η _max )) − sin (ωT ₁ )} / (T ₁ gω) ··· (20) φ ₃ = η _max {1 + COS (ωv _max / (2 η _max ) + ωT ₁ ) −cos (ωv _max / (2 η _max )) − cos (ωT ₁ )} / (T ₁ g) ·· (21) That is, The locus of the point (φ / ω, θ) in the small section A ₃ moves from P2 to P3 (φ ₃ / ω, θ ₃ ) in FIG.

Next, in section 2, the acceleration is set to η = 0 (22). Therefore, the speed of the crane 1 is kept at v = v _max / 2 (23). At this time, the deflection angle θ and the deflection angular velocity φ of the suspended load 3 are θ = η _max (sin (ωt) + sin (ωt −ωT ₁ −ωv _max / (2 η _max )), considering θ ₃ and φ _3. −sin (ωt−ωT ₁ ) −sin (ωt −ωv _max / (2 η _max ))} / (T ₁ gω) ・ ・ ・ (24) φ = η _max {cos (ωt) + cos (ωt−ωT ₁ −ωv _max / (2 η _max )) −cos (ωt −ωT ₁ ) −cos (ωt −ωv _max / (2 η _max ))} / (T ₁ g) (25) Therefore, in the section 2, the locus of the point (φ / ω, θ) moves on an arc centered on the origin O.

Sections 1 and 3 are sections for accelerating to the target speed v _max , whereas section 2 is a section for realizing steady rest at the end of acceleration. The setting method of this section 2 will be described below. The realization of steady rest means that both the swing angle θ of the suspended load and the swing angular velocity φ become zero when the section 3 ends. Therefore, the deflection angle θ of the suspended load
And the shake angular velocity φ are both zero, the acceleration pattern in the section 1 is executed in reverse time. In FIG. 4, the locus of the point (φ / ω, θ) reaches the point P4 from the origin O via P6 and P5, and P4 is the point (−φ ₃ / ω).
₃ , θ ₃ ), that is, it can be derived that the position is symmetrical to P3 with respect to the θ axis. There are two possible methods for determining the transition from section 2 to section 3 depending on whether the sensor value is taken or time is taken. As a method of taking the sensor value,
It is conceivable that the shake angle and the angular velocity are measured or calculated in real time, respectively, and are shifted when θ ₃ and −φ ₃ are reached (angle and angular velocity measurement method). Further, as a method of taking time, a method of setting the duration T _c of the section 2 as follows and shifting after the elapse of T _c is conceivable (time setting method).

In FIG. 4, when the angle formed by the line segment OP ₃ and the θ axis is δ, then δ = tan ⁻¹ {(φ ₃ / ω) / θ ₃ } (26) The amount of movement from P3 to P4 is 2 with the origin as the center.
δ, and the point (φ / ω, θ) draws a circular orbit at an angular velocity ω, so T _c = (2δ + nπ) / ω (n is the smallest integer such that T _c > 0). Determine _c . The addition of nπ is (φ
_This is because δ <0 may occur depending on the position of ₃ / ω, θ ₃ ).

Then, in the section 3, the acceleration pattern is set to the same leg trapezoidal shape as the section 1. As a result, section 3
The crane speed at the end is v _max . Further, since the section 2 is set as described above, both the deflection angle θ and the deflection angular velocity φ at the end of the section 3, that is, at the end of acceleration are zero.

(2) Constant velocity section In the constant velocity section, acceleration η = 0. Therefore, θ =
When 0 and φ = 0 are the initial conditions, no shake occurs.

(3) About deceleration section Since the acceleration in the deceleration section has the opposite sign of the acceleration in the acceleration section, only the signs of the deflection angle and the deflection angular velocity are reversed. Both the swing angle θ and the swing angular velocity φ have zero values.

The maximum acceleration η _max and the maximum velocity v
_{The max} can be freely set within the range of the capacity of the speed control motor 17.

By adopting the above configuration in this embodiment,
Since the crane acceleration changes continuously and the crane speed pattern draws a smooth continuous curve, it is possible to prevent deterioration of control performance due to twisting of the girder and drive shaft, looseness of the reducer, etc. Further, under the conditions described below, which are determined from the position of (φ ₃ / ω, θ ₃ ), acceleration / deceleration can be performed in a shorter time and cycle time can be shortened as compared with the conventional continuous curve speed pattern. The condition that can be shortened is that φ ₃ ≦ 0 (28).

[0033] FIG. 5, the point of the case is φ _3> 0 (φ /
ω, θ). As can be seen from FIG.
In this case, an arc of about one round is required to move from P3 to P4. At this time, n in the equation (27) becomes 1, the value of T _c becomes large, and it takes a long time to accelerate and decelerate, so that the moving time cannot be shortened.

In the above embodiment, the trapezoid of the acceleration pattern is an isosceles trapezoid, but the present invention is not limited to this and may be an isosceles trapezoid.

[0035]

[Examples] The following is a result of calculating the traveling time of a crane based on the equipment specifications of a general container crane that loads and unloads containers on the quay. η _max = 0.5 (m / s ² ) ・ ・ ・ ・ ・ (29) v _max = 3.0 (m / s) ・ ・ ・ ・ ・ (30) T ₁ = 1.0 (sec) ・(31) Suspended load swing cycle T = 8 with moving distance of 50 m
Then, the moving time according to the method described in claim 2 of JP-A-6-305686 is 25.67 seconds, whereas the method according to the present invention can shorten the moving time to 24.67 seconds and 1 second. The swing period T = 8 is about 16 for the rope length of a single pendulum.
m. Considering the lifting height of a container crane for landing a container from a ship on the quay, cargo handling work with a rope length of 16 m or more is frequently performed, so the present invention exerts a great effect.

[0036]

As described above, according to the present invention,
Since it is a speed pattern that draws a smooth continuous curve, it is possible to prevent deterioration of control performance due to twisting of the girder and drive shaft, looseness of the speed reducer, etc., and to accelerate and decelerate in a shorter time than the conventional continuous curve speed pattern. The cycle time can be shortened.

[Brief description of drawings]

FIG. 1 is a block diagram of an automatic crane 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 of the embodiment, and FIG.
Shows the crane acceleration, FIG. 3 (b) shows the crane speed, and FIG. 3 (c) shows the deflection angle of the suspended load.

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

FIG. 5 is a phase plane locus diagram of a deflection angle and its angular velocity when φ ₃ > 0.

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.

FIG. 7 is a time chart showing a conventional crane control method, and FIG. 7 (a) shows crane acceleration.
7B shows the crane speed, and FIG. 7C shows the hanging load deflection angle.

[Explanation of symbols]

 1 crane 2 rail 3 suspended load 4 rope

Claims (4)

[Claims] 1. An operation control method of a suspension crane for stopping swing of a suspended load, wherein an acceleration time change pattern is an acceleration section for accelerating the crane to a predetermined speed, and the predetermined speed accelerated in the acceleration section is held. A constant velocity section and a deceleration section in which the crane is decelerated from the predetermined speed to stop the crane, and an acceleration time change pattern in the acceleration section and the deceleration section is a first trapezoidal pattern in which the acceleration changes according to a first trapezoidal pattern.
A steady rest control method for a crane suspended load, comprising a section, a second section in which the acceleration is kept at zero value, and a third section in which the acceleration changes according to a second trapezoidal pattern. 2. The first trapezoidal pattern comprises a step of linearly increasing or decreasing an acceleration from a zero value to a predetermined acceleration η over time T ₁ , and an acceleration during the time T ₂ η, and a step of linearly decreasing or increasing the acceleration from the acceleration η to a zero value over time T ₃ , wherein the second trapezoidal pattern is over the time T ₃ . Linearly increasing or decreasing the acceleration from zero value to the acceleration η, holding the acceleration η for the time T ₂ , and increasing the acceleration from the acceleration η to the zero value over the time T _1. 2. The method for controlling steady rest of a crane load according to claim 1, further comprising a step of linearly decreasing or increasing. 3. The time T ₁ is equal to the time T ₃ , and the first trapezoidal pattern and the second trapezoidal pattern are congruent isosceles trapezoids. Crane suspension steady control method. 4. When the deflection angle and the deflection angular velocity of the suspended load at the end of the first trapezoidal pattern are θ and φ, respectively, until the deflection angle and the deflection angular velocity become θ and −φ, respectively. The steady rest control method for a crane suspended load according to claim 2 or 3, characterized in that the second section for keeping the acceleration at zero value is held.