JPS5940745B2 - Trolley control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a trolley control system for automatically controlling shaking caused by traveling of cargo in a suspended cargo handling and transporting device such as a crane.

Cranes that transport cargo suspended from ropes or the like often cause the cargo to sway due to the movement of the trolley, which often has an adverse effect on the cargo. Various anti-sway devices have been devised in the past.

A simple method is for the crane operator to check the sway of the suspended load and operate the trolley speed controller to stop the sway.

In other words, this is an operation method that attempts to control the force generated by the acceleration of the suspended load by increasing or decreasing the speed of the trolley.

Figure 1 shows an example of operation in a container crane, where R is the output voltage of the controller operated by the driver, AC is the speed of the trolley, and θ is the swing of the load suspended from the trolley with respect to the time axis t. Each angle is shown.

As can be easily understood from this example, the operation to prevent the trolley from shaking is extremely complicated, and requires considerable skill, especially when the trolley is stopped.

Therefore, various methods have been devised to mechanically stop the swinging of the suspended load, such as a method of stretching a swinging prevention rope from the crane to the hanging device (hook). There is nothing that can prevent the load from swinging, especially in large lanes.
It was necessary to detect and control υθ) in Fig. 1.

FIG. 2 is an example of a trolley control method in which the swing angle θ of a suspended load is detected and negatively fed back as a control signal for a trolley drive motor.

Here, R, x, and θ are the output voltage of the controller, the speed of the trolley, and the deflection angle, as in the case of FIG.

This type of control method that feeds back the swing angle to stop the swing of a suspended load uses constant negative feedback of the swing angle from when the trolley starts to when it stops, so the speed of the trolley changes as expected by the driver. In cranes in which the operator's cab travels with a trolley, the ride is uncomfortable for the operator and is therefore undesirable.

Moreover, since the trolley speed can change rapidly even when accelerating or traversing at a constant speed, it becomes difficult to grasp the spatial position of the cargo, resulting in a decrease in operability.

Particularly, during inching operations for positioning, if the deflection angle feedback signal is included in the trolley speed control signal, accurate positioning cannot be achieved.

The present invention has been made in view of the above points, and includes a trolley control system in which a sway control signal corresponding to the swing angle of a suspended load is negatively fed back as a trolley drive control signal for a suspended cargo handling/transfer device. In order to perform oscillation only while the trolley speed is decelerating, there is a means for detecting the start of decrease in trolley speed, and when the start of decrease is detected by the above means, the oscillation angle can be obtained from the oscillation angle detecting means installed on the trolley. The gist of the present invention is to provide a means for negative feedback of the anti-sway control signal for a certain period of time, and to easily and reliably prevent the suspended cargo from swinging when the cargo is brought to a trolley stop in order to unload the cargo, and during acceleration or constant speed operation. It is an object of the present invention to provide a trolley control system that does not impair the driver's riding comfort and does not cause deterioration of operability during inching operations.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 is a control block diagram for controlling the speed of the trolley 2 traveling on the rail 1. The swing angle of the suspended load 3 carried by the trolley 2 is detected by the detection device 4 and the swing angle is determined. The control signal 1 for speed correction is negatively fed back to the speed setting signal R so as to make it zero.

In the figure, 5 is a DC motor for driving the trolley 2 in a traverse direction, and 6 is a field of this DC motor 5, which is constantly excited by a DC power source 7.

8 is a DC generator, 9 is a field of this generator 8, and 10 is an excitation control device for this generator 8.

A generator 11 for speed detection is provided for the DC motor 5, and the output f of the generator 11 is negatively fed back to the speed command signal r, and the difference signal (f-r) is used as the speed control signal to excite the above-mentioned excitation. The signal is supplied to the control device 10 and amplified to excite the field 9.

Further, the speed command signal r is obtained as a difference signal between the speed setting signal R from the speed setting resistor 12 and the anti-sway control signal, and as described above, the vibration angle detected by the detecting device 4 Voltage e proportional to θ.

is applied from the converter 13 to the amplification control device 14, and from the amplification control device 14 via the relay 15, an anti-sway control signal is obtained.

FIG. 4 shows a control circuit for relay 15.

16 and 17 are voltage comparators, and one voltage comparator 16 compares the voltage E of the IM motor 5 with the reference voltage e.
1, and when E exceeds the reference voltage e1, the output of the comparator 16 becomes 1'', turning on the relay RA.

This relay RA is an a contact and is in an off state when E<01.

In addition, the voltage comparator 17 compares the output R of the speed setting resistor 12 with a reference voltage e2, and when R exceeds the reference voltage e2, the output of the comparator 17 becomes 7'1'' and the relay RB is activated. Turn off.

This relay RB is a b contact and is in an on state when R<e2.

Relay RA and relay RB, which are controlled to open and close in this way, are provided in series between DC power supply 70, and relays RA and R
When both B are in the on state, relay coils 18 and 19
The excitation current is made to flow through.

Relay coil 1B turns on relay R18, which is provided in parallel to the series circuit of relays RA and RB, for a certain period of time, and this relay R18 is a time-limited contact.

Furthermore, the relay coil 19 turns on the relay 15 shown in FIG. Please leave negative feedback.

In the trolley control system configured as in the above embodiment, the swinging of the suspended load can be automatically controlled by controlling the trolley as described below.

That is, as shown in FIG. 5, the trolley 2 is started by first applying the output voltage R of the controller and setting the trolley speed.

At this time, a certain amount of shaking occurs in the suspended load 3, and the swing angle θ is detected by the detection device 4. However, as shown in the control circuit of FIG.
Even if relay RA is turned on beyond reference voltage e1, on the other hand,
Since the relay RB is operated and turned off by the output of the comparator 17, no excitation current flows through the relay coils 18 and 19, and therefore the relay 15 is maintained in the off state, so that the anti-sway control signal is not fed back.

After that, the crane operator turns the controller to the "0" notch near the target position to make the speed setting signal R zero, so the output of the voltage comparator 17 at this time becomes 1", and on the other hand, the speed change of the trolley 2 does not immediately become zero, and the output of voltage comparator 16 still maintains G 11fi.

Therefore, relays RA and RB in FIG. 4 are both turned on and excitation current flows through coils 18 and 19, and
Relay 15 shown in the figure is turned on and the anti-sway control signal V is fed back, and relay R18, which is a time-limiting contact, is also turned on.

After the speed setting output R is returned to zero in this way, for a certain period of time determined by the time limit relay R18, the anti-sway control signal is negatively fed back as a correction signal to the speed command signal r, so the trolley 2 automatically controls the speed. As a result, the deflection angle θ of the suspended load 3 that occurs during deceleration can be quickly reduced.

Here, time-limited relay R is connected in parallel with relay RA t RB
18 is used because the voltage E of the DC motor 5 is the reference voltage e.
When the value becomes less than 1, relay RA turns off, and this relay R
This is because if there is no 18, the excitation current to the relay coil 19 will be cut off. For example, in the case of a container crane, in order to make the swing angle θ zero, it takes about 1 hour after the start of anti-sway control.
0 seconds, and therefore time limit relay R18 is set.

In this case, if the reference voltage e1 of the voltage comparator 160 is set to almost zero, the relay RA will continue to be turned on until the swing angle θ becomes almost zero due to anti-sway control, but this reference voltage e1 will turn off the relay 15 during inching. Since it is necessary to give the speed setting signal R at the same time, the value is set to a relatively large value.

In this way, the driver can easily stop the trolley 2 at a desired position since the anti-sway control signal is not negatively fed back during inching.

Of course, the suspended load will sway to some extent during inching, but the speed of the trolley at this time is small and the resulting swing angle is also small, so there is no practical problem.

In the above embodiment, the swing angle of the suspended load 3 that occurs while the trolley 2 is decelerating near the target position is automatically switched to anti-sway control, which facilitates operations by the crane operator. This makes it possible for even non-skilled people to drive safely.

Further, the trolley 2 receives the anti-sway control signal by negative feedback only during deceleration, and cannot perform anti-sway control during acceleration or constant speed driving, so that the riding comfort and operating characteristics of the trolley 2 are not deteriorated.

Moreover, since the anti-sway control performed during deceleration is automatically canceled after a certain period of time has passed after it starts, accurate positioning can then be performed by negative feedback of the anti-sway control signal during inching operations. I can do it.

Furthermore, since a detection device 4 for detecting the deflection angle θ is installed on the trolley 2, the actual deflection angle can be directly detected by this detection device 4, even when disturbances such as wind blowing occur. Trolley speed can be effectively controlled.

As described above, the present invention provides a trolley control method in which an anti-sway control signal corresponding to the swing angle of a suspended load is negatively fed back as a trolley drive control signal of a suspended cargo handling and transporting device.
Means for detecting the start of a decrease in the speed of the trolley in order to prevent shaking only while the speed of the trolley unloading the load is decelerating; and a swing angle detecting means installed on the trolley when the start of decrease is detected by the means. The main feature is that the system is equipped with a means for negative feedback of the anti-sway control signal obtained from can provide a trolley control method that does not deteriorate the driver's ride comfort or operability.

[Brief explanation of the drawing]

1 and 2 are timing diagrams showing operation examples in a conventional trolley control system, FIG. 3 is a control block diagram showing an embodiment of the present invention, and FIG. 4 shows a relay 15 in the same embodiment. FIG. 5 is a timing diagram showing the operation of the same embodiment. 1...Rail, 2...Trolley, 3...Suspended luggage,
4... Deflection angle detection device, 5... DC motor, 15.
...Relay, 16.17...Voltage comparator, 18.19
...Relay coil.

Claims (1)

[Claims] 1. In a trolley control system that negatively feeds back an anti-sway control signal according to the swing angle of a suspended load as a trolley drive control signal of a suspended cargo handling/transfer device, in order to prevent the swing only when the speed of the trolley lowering the load is reduced. , means for detecting a start of reduction in trolley speed, and means for negatively feeding back a sway control signal obtained from a sway angle detection means installed on the trolley for a certain period of time when the start of reduction is detected in the above means. A trolley control system characterized by comprising: