JPS59128110A - Speed control device for conveyer apparatus - Google Patents

Abstract

PURPOSE:To improve speed control accuracy by correcting a transport speed command value on every short cycle according to a deviation between an actual transport speed of a transported article and a preset value to control the speed of a motor. CONSTITUTION:A set speed is supplied from a transport speed setting device 17 through a speed compensating device 16 and a control device 19 to a motor 1, so that a skew roller conveyer 5 is rotated through a speed reducer 4 to transport a transported article 6. A follower 7 is moved according to the article, and a pulse transmitter 14 sends a pulse signal proportional to the speed of the transported article to be input to the compensating device 16. The compensating device 16 is adapted to find an actual transport speed from the pulse signal 14, calculate a deviation between the speed and a preset speed 17, and compensate a speed command value according to the deviation. The compensation value is output to a control device 19, thereby controlling the motor 1. In this arrangement, speed control is accomplished with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a speed control device for keeping the conveyance speed of a conveyed object constant in an apparatus for conveying a conveyed object.

In order to control the conveyance speed to a constant value in a conveyance device, a speed control device as shown in FIG. 1 has conventionally been used.

In FIG. 1, reference numeral 1 denotes a motor that rotates a cylindrical conveyed object 6 while rotating a scalloped roller conveyor 5 via a speed reducer 4. As shown in FIG.

8 compares the speed setting value given from the speed regulator 81 and the actual speed value fed back from the speed detector 2 coupled to the motor 1, and controls the motor so that the actual speed value becomes equal to the setting value. This is a speed controller that controls the speed of the motor 1 by adjusting the supplied power and the like. In this way, in a conveyance device equipped with a feedback control type speed control device, the speed of the motor 1 that drives the motor 1 is kept constant at a set speed, so there is no slippage between the conveyance device and the transported object. Otherwise, the conveyed object 6 is conveyed at a constant speed.

However, in a conveying device in which a large-diameter cylindrical steel pipe 6 made by welding steel plates is conveyed while being rotated by a skew roller conveyor 5, etc., the adjustment of the skinny angle of each roller of the skew roller conveyor is uneven. The contact force between the rollers and the steel pipe 6 is not uniform over the entire length and circumference because the steel pipe 6 being conveyed is warped, the welded portion is swollen, etc. Therefore, even if the speed of the motor 1 is controlled to be constant, the conveyance speed of the steel pipe 6 is not constant and may vary greatly.

In order to suppress such speed fluctuations of the transported object, a method is sometimes adopted in which the speed of the transported object is directly detected and fed back to the motor speed controller to control the transport speed. If the speed fluctuation is large or the period of fluctuation is rapid, hunting occurs in the control system, making it difficult to control the speed of the conveyed object to be completely constant. Furthermore, in order to prevent such hunting in the control system, the sensitivity of the controller is reduced (this has the disadvantage of increasing control errors and reducing control accuracy).

This invention eliminates the drawbacks of the conventional device as described above,
It is an object of the present invention to provide a speed control device that can control the speed of a conveyed object with high precision.

In order to achieve this object, the present invention detects the conveyance speed of an object to be conveyed by a conveyance speed detector, determines the deviation between the actual conveyance speed value and the speed setting value set by the speed setting device, and calculates the deviation The conveyance speed command value is corrected at relatively short intervals in accordance with the above, and the corrected speed command value is given to a speed controller that controls the motor.

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

FIG. 2 shows an embodiment of the speed control device of the conveying device of the present invention. In the figure, 1, 2, 4, 5 and 6 are the same as those with the same symbols in FIG. 1, so explanations will be given. Omit. Reference numeral 7 denotes a follow-up device configured to move at the same speed as the cylindrical object 6 to be transported, in order to detect the speed of transport of the cylindrical object 6. This follow-up device i7 is configured as follows. . That is, a feed motor 9 for driving the following device 7, which is a torque motor that can be continuously energized even when the rotor is locked, is mounted on the upper surface of a rigid rectangular frame 8 having a U-shaped cross section; Both shaft ends are rotatably supported inside the frame 8! A feed roller 10 is attached to the feed roller 10 and rotates by receiving torque from the feed motor 9 via a transmission device such as a chase, and a frame body 8.
A rotary roller 11 is installed inside the cylindrical body 6 with both shaft ends rotatably supported and rotates on the rail 15 as the frame body 8 moves. A contact detection roller 12 to be pressed is attached to the frame body 8 via a support rod 18, and a rotation pulse transmitter 14 for conveyance speed detection, which is connected to the frame body 8 so as to be interlocked with the rotation roller 11, is mounted on the frame body 8. It is provided. Note that the rails 15 are provided parallel to the conveyance path of the conveyance device. Next 1
Reference numeral 6 denotes a speed correction device, which includes a counter that receives the signal from the pulse transmitter 14 and counts the number of pulses for each period determined by the measurement period setting device 18, and a correction circuit described below. That is, this circuit is composed of a microcomputer with calculation and discrimination functions and an attached input/output circuit, and outputs a speed command value according to the deviation between the actual value and the set value of the conveyance speed.

The speed command value signal outputted from the speed correction device 16 is converted into a voltage signal sent to the signal converter 19 and then output to the motor 1.
A speed command signal is given to a speed controller 8 that controls the speed of the motor. The speed controller 8 uses this speed command signal and the motor 1
The motor 1 is controlled so that the actual speed signal given from the speed detector 2 attached to the motor is equal to the actual speed signal.

Next, the operation will be explained. The speed setting value set by the conveyance speed setting device 17 is output from the speed correction device 16, and in response to the output, a control output is supplied from the speed controller 19 to the rod 1, the motor 1 is driven, and deceleration is performed. The skew roller conveyor 5 rotates with the rotation reduced by the machine 4, and the conveyed object 6
is transported back and forth. For example, when the conveyed object 6 is moving forward, the following device 7 follows it as follows.

The feed motor 9 of the follower 7 rotates, the transmitted feed roller 10 rotates, and the follower 7 moves forward. At this time, since the detection roller 12 is in contact with the side edge surface of the heavy object 6, the follower i7 cannot move forward faster than the object 6, and the detection roller 12 lightly pushes the side edge surface of the object 6. The feed motor 9 rotates at a speed that allows the conveyed object 6 to
The tracking device 7 follows.

The rotating roller 11 receives the weight of the following device 7 and moves to the rail 15.
Since it rolls on top, it rotates with almost no slipping.

A pulse transmitter 14 interlocking with the rotating roller 11 emits pulses with a frequency proportional to the rotational speed of the rotating roller 11, that is, the conveying speed of the object to be transported. The speed correction device 16 outputs a corrected speed command value to the speed controller 19 according to the deviation between the actual conveyance speed value obtained by counting the pulses and the speed setting value. The speed controller 8 controls the speed so that the speed command value and the actual speed value of the motor 1 become equal.
Control output is output.

Correction of the speed command value output from the speed correction device 116 will be explained.

FIG. 8 is a block diagram showing the configuration of the speed correction device 16. To explain the diagram, the pulse transmitter 14
The number of pulses transmitted from An actual conveyance speed value P8 is calculated.

Next, in the comparison section CP, the actual conveyance speed value P8 is compared with the conveyance speed set value BS set by the speed setter 17, and the deviation E therebetween is calculated.

Next, the correction section adds the deviation E to the speed command value Dn-1 currently output (actually obtained in the previous measurement cycle) to obtain a corrected speed command value Dn. This corrected speed command value island is output from the output section OT to the speed controller 8 as the speed command value for the next cycle.

As described above, the number of pulses is counted in the speed correction device 16, and the speed command value Dn-1 is instantaneously corrected immediately after one cycle has elapsed.
is driven by the corrected speed command value Dn. Because of this kind of control, the conveyance speed is not corrected in the middle of one cycle, but the next cycle is controlled by the speed command value corrected by the instantaneous calculation of about 20 milliseconds by the microcomputer. Since the calculation is instantaneous, the cycle can be shortened. Therefore, it can be corrected every short time, so
Actual conveyance accuracy can be improved.

Note that, as shown in FIG. 2, the cylindrical conveyed object 6 has a welded seam 2o, so in order to increase the accuracy of correction, the first period generally consists of one rotation of the conveyed object 6, which rotates while rotating. (The number of periods in the cycle is always an integer.

According to the above-mentioned data 5 +c, according to the present invention, the transported object 6
The pulse transmitter 14, which functions as a speed detector for the follow-up device 7 that tracks The speed command value to be commanded in the next cycle is corrected according to the deviation between the value and the actual transport speed value, and the cycle can also be made relatively short, so the motor is 1 is controlled. Therefore, the accuracy of the conveyance speed becomes highly accurate, and there is no variation in the conveyance distance, and the conveyed object 6
When processing objects, for example, when the induction heating device 1 is moved in and out to harden the object, a remarkable effect can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram explaining a conventional speed control device for a conveyance device, FIG. 2 is a block diagram explaining an embodiment of the speed control device for a conveyance device according to the present invention, and FIG. 8 is a block diagram explaining an embodiment of the speed control device for a conveyance device according to the present invention. FIG. 2 is a block configuration diagram of a speed control device. DESCRIPTION OF SYMBOLS 1...Motor, 6...To be transported, 7...Following device, 14...Transportation speed detector, 16-speed speed correction device, 1
7...Speed setter, 19...Speed controller. Figure 1 Figure 3 11゜

Claims (1)

[Scope of Claims] 1) In a device that is driven by a motor to transport an object, a speed controller that controls the motor so that the actual speed value of the motor becomes equal to a speed command value given from the outside; , a conveyance speed detector that detects the actual conveyance speed of the conveyed object, a conveyance speed setter that sets the conveyance speed of the conveyed object, and a conveyance speed set value set by the conveyance speed setter and the Speed control of a conveyance device, characterized in that it is provided with a speed correction device which determines a deviation from an actual value of conveyance speed detected by a conveyance speed detector and gives a speed command value to the speed controller according to this deviation. Device. 2. A speed control device for a conveying device according to claim 1, wherein the conveying device is a device for conveying an object while rotating it.