JP2831221B2 - Speed control method of overhead crane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed control method for an overhead crane driven by an inverter, and more particularly to a speed control method for an overhead crane capable of performing a stable operation in a low speed range.

[0002]

2. Description of the Related Art In an overhead crane driven by an inverter, a speed controller for controlling a speed is configured by combining an operation unit, a potentiometer, an encoder, and the like. In this case, as shown in FIG. 3, the operation angle of the operation section and the speed signal to the inverter have a linearly proportional relationship.

[0003]

By the way, if the operation angle of the operation unit and the speed signal to the inverter have a linearly proportional relationship as described above, particularly in the case of the overhead traveling crane driven by the inverter, particularly the low angle is required. It is difficult to set and maintain the speed, and there is a problem that stable operation cannot be performed in a low speed region.

The present invention has been made in view of the above-mentioned problems of an overhead crane driven by an inverter, and has been developed in an overhead crane in which an inverter is used for all or any of hoisting, traversing, and traveling drive mechanisms. ,
It is an object of the present invention to provide an overhead crane speed control method capable of performing stable operation in a low speed region.

[0005]

In order to achieve the above object, a method of controlling the speed of an overhead crane according to the present invention is directed to a method of controlling a speed of an overhead crane driven by an inverter. The changing speed command signal is converted by the calculator into a speed signal based on a predetermined characteristic curve having a relationship that is not linearly proportional to the speed command signal and the speed signal curve has a gentle slope at least in a low speed region, The speed signal is output to an inverter.

According to this overhead crane speed control method, a continuously changing speed command signal output from a speed controller is not linearly proportional to the speed command signal by an arithmetic unit. By converting the speed signal curve into a speed signal based on a predetermined characteristic curve having a gentle slope in the area and outputting this speed signal to the inverter, the overhead traveling crane driven by the inverter can be operated stably in the low speed area. can do.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a method for controlling the speed of an overhead crane according to the present invention. The hoisting motor 3 of the overhead crane from the power source 1 via the hoisting inverter 21
1 as well as a traversing motor 32 from the power supply 1 via the traversing inverter 22.
A traveling motor 33 is connected from the power supply 1 via a traveling inverter 23. Then, each inverter 21, 22, 2,
3, operation units 41, 42, and 43 are connected, and operation units 51, 52, and 53 and a potentiometer that constitute a speed controller are connected to the operation units 41, 42, and 43, respectively.

The operation units 41, 42, 43 are provided with an operation unit 51,
The continuously changing speed command signal (analog output value) of the potentiometer connected and slid to 52 and 53 is converted into a digital value, and the entire speed range is set at equal intervals, for example, 20 times.
In addition to the subdivision into 0 points, the subdivided 200 points are not linearly proportional to the speed command signal as shown in FIG. 2 so that stable operation can be performed, particularly in a low speed region. A speed sequence which has a relationship and forms a predetermined characteristic curve in which the speed signal curve has a gentle slope at least in a low speed region (this speed sequence is calculated by the arithmetic units 41, 42,
43. ) Is converted into a speed signal.

Thus, the continuously changing speed command signal output from the speed controller is output to the computing units 41, 42, 4
3 and outputs the converted speed signal to each of the inverters 21, 22 and 23 to drive each of the electric motors 31, 32 and 33 of the overhead crane.

Thus, each of the inverters 21, 22, 2,
3 each motor of the overhead traveling crane driven by
Reference numerals 2 and 33 denote operation units 51 and 5 of arithmetic units 41, 42 and 43, respectively.
By simply operating 2,53, as shown in FIG.
It can be easily and accurately set and maintained at a low speed, so that the overhead crane can be operated stably in a low speed region.

In this embodiment, the operation unit 51,
Although the speed controller is constituted by 52 and 53 and the potentiometer, the same control can be performed by using an encoder, a self-oscillator, or the like instead of the potentiometer.

Further, in the present embodiment, the arithmetic unit 41 has a relationship which is not linearly proportional to the speed command signal, and which forms a predetermined characteristic curve in which the speed signal curve has a gentle slope at least in a low speed region. , 42, and 43, but the present invention is not limited to this. For example, an equation v = f (θ) equivalent to the characteristic curve shown in FIG. , 53, the speed signal v corresponding to the operation angle θ can be calculated.

[0013]

According to the overhead crane speed control method of the present invention, the continuously changing speed command signal output from the speed controller is not linearly proportional to the speed command signal by the calculator. And converting the speed signal into a speed signal based on a predetermined characteristic curve in which the speed signal curve has a gentle slope at least in a low speed region, and outputting the speed signal to the inverter, thereby lowering the overhead traveling crane driven by the inverter. The speed can be set and maintained easily and accurately, so that the overhead traveling crane can be operated stably in the low speed range.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an inverter crane used in the overhead crane speed control method of the present invention.

FIG. 2 is a diagram illustrating a relationship between an operation angle (speed command signal) of a speed controller and a speed signal according to the overhead crane speed control method of the present invention.

FIG. 3 is a diagram showing a relationship between an operation angle (speed command signal) of a speed controller and a speed signal according to a conventional overhead crane speed control method.

[Explanation of symbols]

 1 power supply 21, 22, 23 inverter 31, 32, 33 electric motor 41, 42, 43 computing unit 51, 52, 53 operation unit

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B66C 13/00-15/06

Claims (1)

(57) [Claims] 1. A speed control method for an overhead crane driven by an inverter, wherein a continuously changing speed command signal output from a speed controller is not linearly proportional to the speed command signal by an arithmetic unit. And converting the speed signal into a speed signal based on a predetermined characteristic curve in which the speed signal curve has a gentle slope at least in a low speed region, and outputting the speed signal to an inverter.