JP3081146B2 - Calibration method for crane hanging load deflection angle sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for calibrating a swing angle sensor mounted on a rope-hanging crane for measuring the swing angle of a suspended load suspended on a rope.

[0002]

2. Description of the Related Art Generally, in a crane operation of a rope suspension type crane, a load is lifted, traveled,
It is desired that the so-called cycle time until the load is unloaded is shortened and the cargo handling efficiency is increased as much as possible. At this time, if the load remains at the end of traveling, the load cannot be unloaded for safety reasons. Therefore, it is necessary to wait until the load falls within the allowable range. Therefore, in order to automate the crane, it is necessary to have a steady rest control mechanism for controlling the crane in some way so as not to leave the swing of the suspended load when the crane reaches the destination. Control mechanisms are receiving attention.

The following is known as a specific method of the electric steady rest control mechanism. From the swing cycle of the suspended load, a speed pattern control method that determines the crane's speed pattern up to the movement target position in advance so that the suspended load does not remain when the crane stops due to physical laws (Japanese Patent Publication No. 61-31032, JP-A-6-305686). A feedback control method in which the swing angle of the suspended load is measured by a swing angle sensor, and the measured swing angle and the position measurement value from the position sensor are fed back to the speed command to the motor. A combined method combining speed pattern control and feedback control (NKK Technical Report No. 149: Development of Overhead Crane Sway Control Technology, JP-A-5-319779,
JP-A-7-81876, etc.).

Here, a description will be given of a method of controlling the steady movement of the suspended load of these conventional cranes. Before the description of the control method, a control model which is a premise will be described first. Control Model: 4 is a side view showing a control model of the crane traveling, in FIG. 4, X _t is the running position of the crane, X _c, Y _c, the position of the suspended load, representing the height. The mass of the suspended load is m, and the deflection angle is θ. If the weight of the suspended wire is ignored and the suspended load is treated as a mass point, the equations of motion are expressed by (1), (2), Equations (1) to (3), and (4).

[0005]

(Equation 1)

X _c = X _t + L sin θ (3) Y _c = L cos θ (4)

Here, τ is the tension applied to the suspension wire. Assuming that the length L of the suspension wire is constant and the deflection angle θ is small, it is approximated by sin θ ≒ θ cos θ ≒ 1 (5). Further, from (1) to (4), X _c , Y _c ,
Eliminating τ yields the following equation of motion 2 for the swing of the suspended load.

[0008]

(Equation 2)

Ω ² = g / L (7)

The swing cycle T of the suspended load is expressed by the following equation. T = 2π / ω (8)

Steady-stop speed pattern control: Conventionally, (6)
Various steady rest speed patterns based on the formula have been developed. As an example, JP-A-6-305686 will be described.

From a start position, a predetermined time (T
_{In 1} ), start up linearly up to the predetermined maximum acceleration (α),
After maintaining the acceleration until the operation time from the start position becomes an integer (n) times the swing period, the acceleration is linearly reduced to 0 in the same constant time as the acceleration rise, and the operation at the constant speed (V) is started. Yes. Thereby, the deflection angle becomes 0 (zero) during the constant speed operation. Further, when reaching the position of the following distance (D) to the target stop position, the steady rest is stopped by the same deceleration operation as during acceleration.

The integer n is a value as small as possible defined by the following equation within a range in which a predetermined maximum acceleration α can be realized. V ≦ nαT (9) When T ₁ is determined, the moving distance D during acceleration / deceleration is expressed by the following equation. D = V (nT + T ₁ ) / 2 (ten)

In particular, if the adjustment parameter T ₁ is made equal to the run-out period T, the maximum run-out angle caused by acceleration / deceleration does not exceed the static balancing position determined by the crane acceleration and is minimized. In other cases, since the generated shake angle is smaller than that of the conventional method, even if there is some error in the estimation of the shake period, which is an important control parameter, the control accuracy is not greatly affected.

However, the above-mentioned speed pattern control has the following problems. If there is a disturbance such as an adjustment error of a control parameter or an initial shake at the time of ground separation of a suspended load, a residual shake occurs. As a method of stopping the residual vibration, it is conceivable to measure the deflection angle near the stop target position and newly perform a speed pattern control for the residual vibration prevention, but this increases the cycle time.

Next, a description will be given of a combined system in which the speed pattern control and the feedback control are combined (NKK technology No. 149: development of an overhead crane...). : In order to solve the above-mentioned problem, the swing angle trajectory follow-up control for performing feedback control in all sections including acceleration and deceleration during movement to the target position as described below is also used. Assuming that the deviation between the assumed deflection angle θ _ref caused by the velocity pattern and the actual measured deflection angle θ is Δθ, Δθ follows the following equation 3 as in the equation (6).

[0017]

(Equation 3)

Here, Δv is a speed command correction amount added to the speed pattern command. Here, the correction control amount is expressed by Equation 4.

[0019]

(Equation 4)

By substituting into equation (11), the closed-loop system becomes as shown in the following equation (5).

[0021]

(Equation 5)

That is, the attenuation characteristic (K / L) of the deflection angle deviation Δθ can be arbitrarily specified by the feedback gain K,
Disturbance generated during execution of the pattern control can be converged with a desired attenuation characteristic. The actual speed command correction amount to the lateral traveling motor is given by the following equation by integrating equation (12). Δv = KΔθ (14)

[0023]

In the above-described steadying control of a suspended load of a crane, when a feedback control is performed, a deflection angle sensor is naturally required. In order to guarantee the remaining vibration, or to perform pattern control for detecting the residual vibration and stopping the residual vibration, a vibration angle sensor is always attached.

When the swing angle sensor is mounted on a crane and used, calibration is required by some method. Without calibration, the following adverse effects will occur.

Unless the calibration is performed, the angle measurement value when the suspended load is stopped cannot be grasped, and the absolute swing angle of the suspended load cannot be measured. As a result, an offset occurs in the feedback control input calculated from the angle measurement value, and the control performance deteriorates.

Even if the initial calibration is performed when the deflection angle sensor is mounted, the position of the center of gravity of the hanging tool-the suspended load changes depending on the shape and the weight of the suspended load. There is.

The present invention has been made in view of such a problem. An object of the present invention is to solve the above-mentioned problems,
An object of the present invention is to provide a method capable of accurately and quickly calibrating a crane hanging load deflection angle sensor.

[0028]

According to the first aspect of the present invention,
A swing angle sensor consisting of a two-axis or three-axis optical fiber gyro for measuring the swing angle of a suspended load suspended on a rope is attached to a rope suspended crane, and the swing angle of the suspended load by the swing angle sensor is measured. In carrying out the steadying control of the suspended load using the measured values, from the internal measurement coordinate system of the optical fiber gyro, two or three axes having zero degree when the suspended load is at rest 2 Calculating a correction amount to a three-dimensional or three-dimensional absolute coordinate system, correcting the deflection angle measurement value by the correction amount, and calculating the correction amount when the crane hoists a rope before each run. It is characterized by the following.

According to a second aspect of the present invention, in the first aspect of the invention, the correction amount is calculated by measuring a deflection angle of each axis by the optical fiber gyro for a time longer than a deflection cycle of the suspended load. It is characterized in that it is performed by obtaining an intermediate value between the maximum value and the minimum value of the shake angle measurement values.

The third aspect of the present invention is the first or second aspect.
In the invention described above, the absolute deflection angle of each axis is obtained by subtracting the correction amount from the instantaneously measured value of the optical fiber gyro.

According to the present invention, in the steadying control of the suspended load, the deflection angle sensor is calibrated before every run, so that the position of the center of gravity of the suspended load-hanging tool system changes depending on the type of the suspended load. However, the absolute swing angle can be accurately grasped, and the occurrence of the offset of the control input when performing the feedback control can be prevented. In addition, since the calibration is performed using the rope winding time before each run, there is no adverse effect such as prolonging the transport time.

[0032]

Next, a calibration method according to the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an automatic crane control apparatus to which the deflection angle sensor calibration method of the present invention is applied. The steadying control method according to the present embodiment employs a method that uses both the speed pattern control and the swing angle feedback control.

In FIG. 1, reference numeral 1 denotes a crane. The crane 1 travels on the rail 2 in the X direction shown in FIG. 1 while suspending the suspended load 3 attached to the lower end of the rope 4. The traveling of the crane 1 is controlled by a crane position detecting device 11, a rope length detecting device 12, a swing cycle calculating device 13, a crane movement target command device 14, a speed pattern generating device 15, a swing angle sensor 16, An angle sensor calibrating device 17, a feedback control command generating device 18, an adder 19, a traveling motor control device 20, and a speed control motor 21. As the deflection angle sensor 16, a two-axis measurement optical fiber gyro was used (or a three-axis measurement optical fiber gyro was used). The rope length target command device 22, the winding motor control device 23, and the winding motor 24 control the lifting / lowering of the suspended load.

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. 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 detecting 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 amount of rotation of a winding motor 24 of the rope 4 and the like.

The swing period calculating device 13 is a device for calculating the swing period of the suspended load 3 based on the detection signal from the rope length detecting device 12. This shake period calculation device 13
The swing period is calculated mainly based on the hanging rope information from the rope length detecting device 12. In some cases, the swing period is calculated in consideration of auxiliary information such as the amount of hanging load.

The speed pattern generating device 15 is a device for generating a speed pattern to be given to the crane 1 based on a calculation signal from the shake period calculating device 13 and a signal from the crane movement target command device 14. The deflection angle sensor (optical fiber gyro) 16 is a device that measures the deflection angle and the deflection angular velocity of the suspended load 3 suspended by the rope 4. Feedback control command generator 18
Is a device that performs an appropriate operation on the signal from the deflection angle sensor 16. The adder 19 is connected to the speed pattern generator 15.
And a signal from the feedback control command generator 18 to add a speed command for steadying control. The traveling motor control device 20 includes a minor control loop for realizing an operation speed command externally given to the speed control motor 21. The winding control is controlled so as to wind up / down at a constant speed up to the rope length target command value.

FIG. 2 is a side view showing the operation procedure of the crane equipped with the automatic control device of FIG. Crane 1
As shown by in FIG. 2, unwind to grip the cargo,
After grabbing the suspended load 3, as shown in FIG. 2, it is wound up to a rope length capable of avoiding the obstacle 5, and while performing steadying control, travels to the transfer target point as shown in FIG. In an overhead crane of a steel mill, a hoisting speed is 8 m / min, a hoisting amount is 2 to 3 m, and a rope length at a position where a load is grasped is generally about 10 m. At this time, the time required for the winding operation is about 15 to 23 seconds. The swing cycle of the suspended load is approximately 6 seconds.

FIG. 3 shows a deflection angle sensor 1 for winding up.
6 is a graph showing a time chart of a shake angle measurement value of No. 6; As shown in FIG. 3, the suspended load has a pendulum motion having an initial amplitude due to a displacement of the crane position at the time of lifting, and the initial calibration of the deflection angle sensor is insufficient. Not detected as zero degrees. That is,
It can be seen that there is an offset in the measured swing angle. By calculating the center of this pendulum motion and removing the offset of the measured swing angle, the absolute swing angle can be grasped. By using this absolute deflection angle as an input to the feedback control command generator 18, the offset of the feedback control amount can be eliminated.

The specific method of the calibration according to the present invention is as follows: For each section longer than the swing cycle of the suspended load, for example, for each section of 7 seconds,
The maximum value (θ _max ) and the minimum value (θ _min ) of the shake angle measurement value are taken out, and the correction amount (θ) is obtained by the following equation (1), θ _zero = (θ _max + θ _min ) / 2 (1) _zero ). And (1)
The calculation of the equation is performed every time the interval is updated, and θ _zero is updated. θ
_{Since max} and θ _min are the maximum value and the minimum value in a time section longer than the suspended load swing cycle, they always match the peaks and valleys of the vibration. Therefore, accurate calculation of θ _zero can be performed. Using the latest θ _zero obtained in this way, the absolute deflection angle (θ _abs ) during traveling of the crane is constantly calculated by the following equation (2), θ _abs = θ _raw −θ _zero (2) I do. And the absolute deflection angle (θ _abs )
Is used by substituting it into the actual shake angle measurement value θ in the above-described equation (11). Here, θ _raw is raw data (an instantaneous measurement value) measured by the deflection angle sensor. Furthermore,
Since the calculation of θ _zero was performed when the crane was hoisted before each run, the operating efficiency of the automatic crane did not decrease.

[0041]

As described above, in the method of calibrating the hanging load deflection angle sensor of the crane according to the present invention, since the calibration is performed before every traveling, the position of the center of gravity of the hanging load-hanging tool system changes depending on the type of the hanging load. Even so, the absolute angle (absolute deflection angle) can be accurately grasped, the offset of the control input at the time of performing the feedback control can be prevented, and the calibration using the winding time before each run can be performed. Therefore, there is no adverse effect such as prolonging the transport time, so that the efficiency is high, and thus an industrially useful effect is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an automatic control device for a crane to which a deflection angle sensor calibration method of the present invention is applied.

FIG. 2 is a side view showing an operation procedure of a crane equipped with the automatic control device of FIG.

FIG. 3 is a graph showing a time chart of a measured swing angle of a swing angle sensor during winding.

FIG. 4 is a side view showing a control model of crane traveling.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Crane 2 Rail 3 Suspended load 4 Rope 5 Obstacle 11 Crane position detecting device 12 Rope length detecting device 13 Shake period calculating device 14 Crane movement target command device 15 Speed pattern generator 16 Shake angle sensor 17 Shake angle sensor calibrating device 18 Feedback Control command generator 19 Adder 20 Traveling motor controller 21 Speed control motor 22 Rope length target commander 23 Winding motor controller 24 Winding motor

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Koichi Abe 1 Onocho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Inside the steel pipe electrical installation industry Co., Ltd. (56) References JP-A-7-71958 (JP, A) JP-A-6-191790 (JP, A) JP-A-7-69580 (JP, A) JP-A-5-126579 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B66C 13 / 06,13 / 22 G01C 9/00

Claims (3)

(57) [Claims] 1. A two-axis or three-axis system for measuring a swing angle of a suspended load suspended on a rope by a rope suspended crane.
Attaching a deflection angle sensor consisting of an optical fiber gyro for axis measurement, and performing the anti-sway control of the suspended load using the deflection angle measurement value of the suspended load by the deflection angle sensor, from the internal measurement coordinate system of the optical fiber gyro, A correction amount to a two-dimensional or three-dimensional absolute coordinate system composed of two or three axes having zero degree when the suspended load is stationary is calculated, and the deflection angle measurement value is calculated based on the correction amount. A method for calibrating a crane hanging load deflection angle sensor, wherein the correction is performed and the calculation of the correction amount is performed at the time of hoisting a rope before each traveling of the crane. 2. The method according to claim 1, wherein the correction amount is calculated by measuring a deflection angle of each of the axes by the optical fiber gyro for a time longer than a deflection cycle of the suspended load, and calculating an intermediate value between a maximum value and a minimum value of the deflection angle measurement value. 2. The method according to claim 1, wherein the value is obtained by obtaining a value. 3. The method according to claim 1, wherein the absolute deflection angle of each axis is obtained by subtracting the correction amount from an instantaneous measurement value of the optical fiber gyro.