JPH02133084A - Conveyor drive control method - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a drive control method for starting and stopping a transfer conveyor.

(Prior technology) When conveying products such as round steel materials and steel pipes using a transfer conveyor, the chain conveyor is operated intermittently to send the products one after another, but a counter using a photoelectric switch is installed in the middle of this comparison. A counter is installed to count the number of products being transported. Conventionally, the intermittent operation of the conveyor has been performed by repeating the operating and stopping states of the motor that drives the conveyor, and the operation is controlled by the curve shown in FIG.

This figure 3 shows the motor from start to stop, and figure (a) is the speed command curve for the motor drive circuit, and figure (mouth) is the rotational speed of the motor at the same timing as figure (a). This is a curve showing changes. In Figure 3, 1 is the starting point of motor drive, and the drive is controlled so that it accelerates in the range a, operates at a constant speed in the range b, decelerates in the range C, and stops at point t2. It is something to do.

Here, the acceleration range a is controlled to linearly accelerate, and the deceleration range C is controlled to linearly decelerate, and the conveyor is also driven and controlled according to this control.

(Problems to be Solved by the Invention) However, in the conventional control method as described above, the product may shake in the front-back direction when the intermittent operation of the conveyor starts and stops. And if this blurring occurs in the photoelectric switch that detects the counting error,
There is a problem in that the detection output of the photoelectric switch results in double counting and overcounting. That is, when the conveyor starts, as shown in Figure 4 (a), the conveyor 1
The product 2, such as a round steel material, moves in the opposite direction to the traveling direction of the machine, and the photoelectric switch 3 detects it twice. In addition, when the conveyor belt is stopped, the product 2 swings forward with respect to the running direction of the conveyor 1 and then moves backward again, resulting in double detection by the photoelectric switch 3, as shown in the same figure (opening). Ta.

SUMMARY OF THE INVENTION In view of these conventional problems, the present invention has been made with the object of providing a control method that prevents the conveyed products from bulging when the intermittent operation of a conveyor is started or stopped. .

(Means for Solving the Problems) In order to solve the above-mentioned conventional problems, a single-motion control method for a conveyor according to the present invention provides a method for starting a transfer conveyor,
The drive control method at the time of stop is a drive control method of the transfer conveyor drive motor such that the drive speed of the transfer conveyor is initially gradually accelerated when accelerating after a start, and is finally gradually decelerated when decelerating before stopping. The control voltage is controlled based on a quadratic function curve.

(Function) According to the method of the present invention, by the method described above, by gently accelerating the conveyor for a product that is stationary at the start, it is possible to accelerate both products while synchronizing them.
On the other hand, when stopping, the inertia of the product moving together with the conveyor is weakened by the deceleration of the conveyor, and the final gradual deceleration synchronizes the two and brings them to a stop.

(Embodiment) A conveyor drive control method according to an embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is an explanatory diagram of a transfer conveyor drive control method in which the method of the present invention is implemented. In Fig. 1, ■ is a chain conveyor, and products 2 such as round steel materials and steel pipes are conveyed on this conveyor 1 and counted by a photoelectric switch 3. Here, the conveyor 1 is intermittently is driven by. The conveyor 1 is operated by a motor 5 that drives a subrocket 4, and the motor 5 is driven by changing a control voltage in a motor drive circuit 7 based on a motor speed command from a sequencer 6.

8 is a manual setting means using the operation panel in the operator's room, and input IP of the speed pattern of the conveyor which varies depending on the diameter of the product 2;
and an acceleration/deceleration curve correction input IP2, and the set speed pattern and acceleration/deceleration curve correction signal are input to the sequencer 6. Further, reference numeral 9 denotes automatic setting means, which inputs signals of speed instruction and acceleration/deceleration constant instruction to the sequencer 6 based on preset arithmetic processing based on the input IP3 of the size of the product 2.

With the above configuration, the operation of the drive control method for the conveyor 1 will be described below with reference to the control curve shown in FIG. 2. In the present invention, control is performed according to the control curve shown in FIG. 2 using the configuration shown in FIG. It shows up to the stop. Figure 2 (a) shows the curve of the motor speed command output from the sequencer 6, and the figure (opening) shows the change in the rotational speed of the motor 5 at the same timing as in Figure (a) (in other words, the change in the driving speed of the conveyor 1). It is a figure showing a change) curve.

In the figure, T1 is the starting point of motor drive, and the drive is controlled so that it accelerates in range A, operates at a constant speed in range B, decelerates in range C, and stops at point T2. The overall control is the same as the conventional example described above, but the acceleration range A. l! : The control method for deceleration range C has changed significantly. That is, in acceleration range A, immediately after the start of point T, acceleration is slow (in other words, low acceleration rate).
and gradually accelerate the speed until it reaches a constant speed.
Accelerate according to the following function curve. For example, if the command signal is the control voltage of the seventh motor 5, the coefficient is a, and the time is t, then V=a t" ... (1). On the other hand, in the deceleration range C, initially decelerates at a high deceleration rate, and decelerates as gently as possible just before stopping using a quadratic function curve similar to when accelerating.This kind of acceleration control at the start and deceleration control at the time of stopping is , is performed by the calculation processing of the sequencer 6, but the setting conditions for the calculation are performed by the manual setting means 8 and the automatic setting means 9.In other words, the manual setting means 8 inputs the speed of the conhair 1, which varies depending on the diameter of the product 2. At the same time, the acceleration/deceleration curve is arbitrarily selected, adjusted, and inputted.Furthermore, the automatic setting means 9 stores the speed curve for each size of the product 2 in the CPU, and it is only necessary to input the size. Then, the sequencer 6 performs arithmetic processing based on the setting condition selected from both setting means 8ζ9, controls the motor drive circuit 7 according to the curve of the above-mentioned pattern, and drives the motor 5.As a result, the conveyor l is Immediately after the start, the conveyor is gently accelerated, and the speeds of the product 2 and the conveyor I are synchronized, and thereafter the speed is controlled to be accelerated.

On the other hand, at the beginning of deceleration, the speed is reduced at a high deceleration rate, and immediately before stopping, the speed is gradually reduced so that the speeds of the product 2 and the conveyor 1 can be synchronized and stopped.

Note that the coefficient a of the above equation (1) calculated by the sequencer 6
By changing the diameter of the product 2, the speed pattern (acceleration/deceleration rate) can be easily changed.

In addition, in order to realize control using a quadratic function curve during acceleration/deceleration, for example, in the sequencer 6, when accelerating, the acceleration constant is added to the power of 2 for each Melsec cycle, and when decelerating, the added acceleration constant is memorized and the deceleration is performed. Melsec l constant
This is done by subtracting and squaring every cycle.

(Effects of the Invention) As described above, the present invention controls the control voltage of the motor based on a quadratic function curve so that the drive speed of the conveyor is gradually accelerated immediately after the start and is gradually decelerated immediately before the conveyor starts. Therefore, when starting, the product and the conveyor can be accelerated while being in the same bin, and when stopping, the product and the conveyor can be synchronized and decelerated to a stop. Therefore, when the conveyor is started and stopped in intermittent operation, This is a very effective invention because it can prevent the products being transported, such as round steel materials, from wobbling and eliminate counting errors.

[Brief explanation of the drawings] ． Figure 1 is an explanatory diagram showing an embodiment of the method of the present invention, and Figure 2 (
A) (Opening) is a curve diagram showing the motor speed command and a curve diagram showing changes in the motor rotation speed, Figure 3 (A) (Opening)
4 is a curve diagram showing a motor speed command and a curve diagram showing a change in motor rotation speed in the conventional method, and FIG. 1 is a conveyor, 2 is a product, 5 is a motor, 6 is a sequencer, and 7 is a motor drive circuit. Figure 2-4 Fl″l

Claims (1)

[Claims] (1) A drive control method when starting and stopping a transfer conveyor, wherein the drive speed of the transfer conveyor is initially gradually accelerated when accelerating after starting, and finally gradually decelerated when decelerating before stopping. ,
A method for controlling the drive of a conveyor, characterized in that the control voltage of the transfer conveyor drive motor is controlled based on a quadratic function curve.