JPH04116014A - Transfer control onto linear carrier device - Google Patents

Abstract

PURPOSE:To smooth transfer of a pallet onto a linear carrier device from a conveyer carrier device by starting the linear carrier device in a condition where the speed of the linear carrier device becomes the same as that of a conveyer when a pallet has been transferred completely after the pallet started to be transferred onto the linear carrier device. CONSTITUTION:When a pallet 4 delivered by a slat conveyer is transferred onto the upstream edge of a linear carrier device 1 and a proximity switch 13 is turned on, the point of time is regarded as a reference start timing, and the linear carrier device 1 is started in a prescribed operating condition. The pallet 4 is moved onto the linear conveyer 1 by the full length distance of the pallet and when the transfer is completed, the linear carrier device 1 is excited with three-phase alternating current so that the speed of the linear carrier device 1 becomes approximately the same as that of the slat conveyer 2. It is thus possible to prevent a slip between the pallet, 4 and the slat conveyer 2, provide smooth transfer.

Description

[Detailed description of the invention] [Industrial application field].

The present invention relates to a transfer control method for transferring a pallet for transferring workpieces from a conveyor type transfer device that carries out constant speed transfer to a linear transfer device.

[Prior art]

Recently, Japanese Patent Application Laid-open No. 55-86307 and Japanese Patent Application Laid-open No. 62-
As described in Publication No. 210162, linear conveyance devices that drive workpiece transfer pallets using linear motors are being put into practical use in automobile factories due to their high-speed operating characteristics. Linear conveyance equipment is not applied throughout the line,
A constant speed conveyor type conveyor type conveyor device such as a slat conveyor is applied to a part of the pallet conveyance line. Therefore, it is also common practice to transfer pallets from a linear conveyor to a conveyor conveyor or vice versa.

By the way, when carrying out a predetermined stroke using a linear conveying device, there are four steps: start-up, rapid acceleration conveyance, constant speed high-speed conveyance, rapid deceleration conveyance,
The stop operations are performed sequentially.

When transferring a pallet from a constant-speed, low-speed conveyor-type conveyor to a linear conveyor, it is necessary to synchronize the conveyance speed of the linear conveyor with the conveyor speed of the conveyor-type conveyor.

[Problem to be solved by the invention]

It is possible to control the conveyance speed of the linear conveyance device by providing a normal linear conveyance device with a control means that detects the conveyance speed of the pallet using an encoder or the like and performs precise feedback control of the conveyance speed.

However, for a short time after the transfer starts, the magnetic force from only a few of the multiple linear coils acts on the pallet, and the pallet is transported at a constant speed by the driving force of the conveyor-type transport device. As the pallet is transferred to the linear conveyance device, the number of linear coils that contribute to the conveyance increases and the conveyance driving force on the linear conveyance device side increases, so the linear conveyance device is rarely controlled by the above-mentioned feedback control. It's impossible.

If the conveyance speed of the linear conveyance device becomes greater than the constant conveyance speed of the conveyor-type conveyance device before the transfer of the pallet to the linear conveyance device is completed, the linear motor is braked and an induced current in the opposite direction is generated in the linear coil. This causes problems such as confusion in controlling the current and voltage supplied to the linear coil.

Furthermore, if the pallet is transported at a higher speed than the constant transport speed by the transport driving force of the linear transport device before the transfer is complete, slippage may occur between the pallet and the conveyor-type transport device, causing the pallet or the conveyor-type transport device to slip. There is a problem with damage.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for controlling transfer to a linear transfer device that allows a pallet for transferring a workpiece to be transferred smoothly from a conveyor-type transfer device to a linear transfer device.

[Means to solve the problem]

A method for controlling transfer to a linear conveyance device according to the present invention includes:
A control method for transferring a pallet from a conveyor-type transport device that transports a pallet for workpiece transfer at a constant speed to a linear transport device that transports the pallet using a linear motor, wherein the front end of the pallet in the transport direction is the linear transport device. The linear conveyance device is activated to a predetermined operating state from the reference start timing when the predetermined transfer start position has been reached, and the conveyance distance of the pallet after the reference start timing is determined in real time, and the conveyance distance of the pallet reaches the predetermined distance. When the conveyance speed of the linear conveyance device becomes approximately equal to the constant conveyance speed of the conveyor type conveyance device, control of predetermined speed characteristics for the linear conveyance device is started.

[Effect]

In the method for controlling transfer to a linear transfer device according to the present invention, the linear transfer device is set in a predetermined operating state from a reference start timing when the front end of a pallet for transferring a workpiece in the transfer direction reaches a predetermined transfer start position on the linear transfer device. start it. The above-mentioned predetermined operating state means that when the pallet is transported a predetermined distance (however, this predetermined distance is approximately the entire length of the pallet) by the linear transport device alone, it is approximately equal to the constant transport speed of the conveyor-type transport device. Excitation current that provides the transport speed (for example, N% excitation of full excitation, N≦1
00).

When the linear conveyance device is started, only a portion of the magnetic force of the linear coil of the linear motor acts on the pallet, so the pallet is conveyed at a constant speed by the driving force of the conveyor type conveyance device.

The conveyance distance of the pallet after the reference start timing is determined in real time, and when the conveyance distance of the pallet reaches the predetermined distance, the pallet is detached from the conveyor-type conveyor and completely transferred onto the linear conveyor. Moreover, since the conveyance speed of the linear conveyance device becomes approximately equal to the constant conveyance speed, control of predetermined speed characteristics for the linear conveyance device is started from this point.

〔Effect of the invention〕

According to the method for controlling transfer to a linear conveyance device according to the present invention, as explained in the [Operation] section above, the linear conveyance device is operated in a predetermined manner while the pallet conveyance distance is less than a predetermined distance after the reference start timing. This simplifies the control of the linear conveyance device, and prevents the linear motor of the linear conveyance device from being braked and causing an opposite induced current in the linear coil.

When the conveyance distance of the pallet after the standard start timing reaches a predetermined distance, the pallet is sufficiently transferred onto the linear conveyance device, and the conveyance speed of the linear conveyance device becomes approximately equal to the constant conveyance speed of the conveyor type conveyance device. Since control of predetermined speed characteristics is started for the linear conveyance device, the pallet can be smoothly transferred from the conhair type conveyance device to the linear conveyance device, and the linear motor is braked and the linear coil is moved in the opposite direction. No induced current is generated. In addition, since the pallet is not transported by the linear transport device at a higher speed than the constant transport speed before the transfer of the pallet is completed, no slip occurs between the pallet and the conveyor-type transport device.

〔Example〕

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

First, a conveyance line consisting of a linear conveyance device 1 installed in an automobile factory and a slat conhair 2 arranged in series at the upstream end of this linear conveyance device 1 will be described.

As shown in FIGS. 1 to 3, this conveyance line is for conveying a pallet 4 on which a vehicle body 3 is placed, and will be explained by defining the front, rear, left, and right directions as shown in FIG.

To explain the linear conveyance device 1, it is a roller row 6 having a plurality of idle rollers 5, one row on the left side and one row on the right side that supports the left and right parts of the pallet 4 so as to be able to transport them.
Also, guide rollers 7 for guiding the left side of the pallet 4 are provided at regular intervals.
Guide rollers 7 are provided at regular intervals to guide the right side surface of the roller.

At the left end of the linear conveyance device 1, linear coils 8 of the linear motor are provided at predetermined intervals so as to approach and oppose the left side of the pallet 4, and at the right end of the linear conveyance device 1, linear coils 8 of the pallet 4 are also installed. They are provided at predetermined intervals so as to closely face each other on the right side surface.

The pallet 4 is a hollow box-shaped body made of steel, and a thick core member 9 made of steel and an aluminum plate 10 on the outside are provided at the left end thereof, and a thick core member made of copper is provided at the right end of the pallet 4. 9 and an aluminum plate 10 on the outside thereof.

When three-phase AC power is supplied to the linear coil 8,
A moving magnetic field that moves forward is generated in the linear coil 8, and the magnetic force of the moving magnetic field acts on the core member 9, so that the pallet 4 is driven forward. In other words, the linear coil 8 and the core member 9 constitute a linear motor.

Here, the linear conveyance device 1 is provided with a plurality of stations at predetermined intervals, and a pallet 4 is provided so as to correspond to each station.
After each predetermined work is performed on the upper car body 3 at a predetermined cycle time, all pallets 4 are simultaneously conveyed to each adjacent station, and from the slat conveyor 2 to the most upstream stage of the linear conveyance device 1. Pallet 4 can be transferred.

Next, to explain the slat conveyor 2, endless chains 21 are arranged on the left and right sides of the slat conveyor 2, respectively, and are hung on four sprockets 20. A large number of steel plate members 22 elongated from side to side are arranged in a caterpillar shape in the front and back direction, and the left and right parts of each plate member 22 are connected to the corresponding endless chain 21, and the rear end side (not shown) is connected to the corresponding endless chain 21. For example, the slat conveyor 2 is driven at a constant speed in the direction of the arrow in FIG. 2 by driving a pair of lower left and right sprockets 20 at a constant speed with an electric motor (path shown). Furthermore, pallets 4 are placed on the slat conveyor 2 at predetermined intervals (for example,
5.5 m), stoppers 23 having a T-shaped cross section are attached to the slat conveyor 2 at predetermined intervals.

Next, a control system for the above-mentioned conveyance line will be explained.

In order to detect the conveyance distance of the pallet 4, a rack member 11 is provided at the center of the lower surface of the pallet 4 and extends in the front-rear direction over the entire length.
Row encoder 1 that rotates by meshing with rack 1
2 are provided at predetermined intervals (this is shorter than the entire length of the pallet 4), and one of them is provided at the upstream end of the linear transport bag W1.

Further, a proximity switch 13 is provided near the upstream end of the linear conveyance device 1 in order to detect when the front end of the pallet 4 has reached a predetermined transfer start position.

The slat conveyor 2 is provided with a rotary recorder 24 operatively connected to a sprocket 20 via a pair of sprockets and an endless chain.

FIG. 4 shows a configuration diagram of a control system, in which a control unit 30 is provided to control six sets of linear coils 8 on the most upstream side (rear side) among a large number of linear coils 8 of the linear conveyance device 1. A drive circuit unit 31 having a built-in silisk is provided corresponding to each linear coil 8, and each drive circuit unit 31 controls three-phase alternating current according to a control signal supplied from the control unit 30, and controls the three-phase alternating current. AC is supplied to the linear coil 8. Note that a downstream linear coil (not shown) is controlled by a control unit (not shown).

Rotary encoder 12 and rotary encoder 24
and the proximity switch 13 are electrically connected to a control unit 30, and various commands and information are supplied to the control unit 30 from a host computer 40.

The control unit 30 is equipped with a microcomputer, and this microcomputer has a ROM (read memory).
only memory), at least slat conveyor 2
A control program for transfer control for transferring the linear conveyance device 1 to the heparet 4 is stored in advance.

Next, a method of transfer control performed using the linear conveyance device 1, slat conveyor 2, and control system will be described.

First, an overview of the control will be explained. As shown in FIGS. 2 and 5, the front end of the pallet 4 moves from the slat conveyor 2 to the transfer start position at the upstream end of the linear conveyor 1, and the proximity switch is activated. The time point when 13 is turned on is set as the reference start timing. When the pallet 4 moves forward by a predetermined distance L (this distance is approximately the total length of the pallet 4) after this reference start timing, the pallet 4
The rear end comes off the stopper 23 of the slat conveyor 2, and the transfer is completed.

Until the transfer of the pallet 4 is completed, the pallet 4 is mainly conveyed by the driving force of the slat conveyor 2, and is conveyed at a constant conveyance speed (S) of the slat conveyor 2.

The linear conveyance device 1 is started at the standard start timing, but as the pallet 4 moves, the magnetic force acting on the pallet 4 from the linear coil 8 increases, so it is almost impossible to precisely control the speed of the linear conveyance device 1. In view of this, the linear conveyance device 1 is activated to a predetermined operating state from the transfer start timing.

The above-mentioned predetermined operating state means that the pallet 4 is moved to the linear conveyance bag 2 while applying magnetic force to substantially the entire area on both left and right sides of the pallet 4.
1, the time Tl (however, TI
=L/VS), the transport distance is L (this corresponds to the area of region R) and the transport speed is vS
This is a state in which the motor is excited by three-phase alternating current, and in this embodiment, it is a state in which the motor is fully excited, for example, at 90%.

In this way, if the predetermined operating state is set as described above, when the pallet 4 is transported a predetermined distance from the reference start timing, the transport speed by the linear transport device 1 is set to v.
Therefore, the pallet 4 can be transferred smoothly. The magnetic force of the linear coil 8 acting on the pallet 4 increases from the start of the transfer to the completion of the transfer, but the conveyance speed due to the driving force of the linear motor never exceeds the constant conveyance speed ■S, so the linear The linear motor of the conveying device 1 is not braked, and no slip occurs between the pallet 4 and the slat conveyor 2.

It is assumed that when the transfer is completed, control of the predetermined speed characteristics (solid line VA in FIG. 5) for the linear conveyance device 1 is started.

Next, the transfer control to the linear conveyance device 1 will be explained based on the flowchart of FIG. 6. In addition, S in the figure
i (i=1.2, . . . ) indicates each step.

First, when control is started, the flag F is reset in the initial settings, and the output of the proximity switch 13 is read (S
1), it is determined whether the output of the proximity switch 13 is ON or not (S2), and initially the output 4 is connected to the linear conveyance device 1.
When it has not moved to F=0, the proximity switch 13
Since the output is OFF, steps 81 to S3 are repeated, and when the front end of the pallet 4 advances to the position of the proximity switch 13, the proximity switch 13 is turned ON, so the process moves to S4 and flag F is set. It is determined whether or not the
= 0, so the process moves to S5, where a control signal to make the linear coil 8 90% of full excitation is output, and then the output of the rotary encoder 12 is read, and the output is counted up and stored in the soft counter (S6). Next, based on the count-up value of the rotary encoder 12, the conveyance distance of the pallet 4 after the reference start timing is calculated and stored in the memory (S7). Next, it is determined whether the conveyance distance is smaller than the predetermined path ML (38), and Ye
At time s, the transfer of the pallet 4 is not completed, so the process returns to S1 and steps S1 to S8 are repeated at minute predetermined intervals. Eventually, the transfer of pallet 4 will be completed and D
≧L, and the conveyance speed by the linear conveyance device 1 is approximately v
When S is reached, flag F is set (39), and then 314
5, acceleration control of the speed characteristic of the straight line VA in FIG. 5 for the linear coil 8 is executed based on a command from the host computer 40, and then the process returns to SL.

After that, since F=1, it shifts from Sl to SIO, and 310
At 36, the output of the rotary encoder 12 is read and stored, and then the rotary encoder 12
The conveyance speed ■ of pallet 4 is calculated using the output of (
Sll). In this case, for example, the rotary encoder 12
The conveyance speed (■) can be determined using the period of the output pulse.

Next, it is determined whether the conveyance speed ■ is v=0 (Sl2
), since initially V=O is not established, the process moves to 313, and in S13 it is determined whether the conveyance speed V is smaller than the high-speed constant-speed conveyance speed VM shown in FIG. ■〈The VM moves to S14, and S1 to S4 and S10 to S14 are repeated, but the V
When ≧VM, the process moves from 313 to 315, and in S15, control of the characteristics of the constant conveyance speed VM shown in FIG. ,S1
~S4.310-313 and S15 will be repeated. After the above-mentioned constant speed conveyance, the pallet 4 is decelerated and stopped by deceleration control, but when the conveyance speed becomes = 0, the process moves from Sl, 2 to S16, flag F is reset, and the process changes from 316 to 51. return. As described above, the pallet 4 is transferred from the slat conveyor 2 to the linear conveyance device 1, and after the transfer is completed, the pallet 4 is conveyed at acceleration, constant speed, and deceleration, and then the pallet 4 is stopped.

Note that the weight of the vehicle body 3 placed on the pallet 4 and transported varies depending on the vehicle type, and the host computer 40 has data on the vehicle type and the weight of the vehicle body 3 for each vehicle type, so S14.
In S1'5, the linear coil 8 is controlled according to commands from the host computer 40. In the above embodiment, the case where the conveyance speed S of the slat conveyor 2 is constant has been explained, but in the case where the constant conveyance speed of the slat conveyor 2 is switched in a plurality of ways, the The conveying speed of the slat conveyor 2 may be determined using the output, and the linear coil 8 may be controlled taking this into consideration.

As explained above, the linear coil 8 is activated to a predetermined operating state from the start of transfer of the pallet 40, and after the start of transfer, the pallet 4 moves a predetermined distance, and the pallet 4 is removed from the slat conveyor 2 and transferred to the linear conveyor W1. When the conveyance speed becomes approximately equal to the constant conveyance speed ■S of the slat conveyor 2, control of the predetermined speed characteristics for the linear coil 8 is started, so that the pallet 4 can be transferred very smoothly and effortlessly. This has the following effects: there is no possibility that the linear motor is braked and an oppositely directed induced current is generated in the linear coil 8, and there is no slippage between the pallet 4 and the slant conveyor 2. It will be done.

Incidentally, the present invention can be similarly applied to control when pallets are transferred from various constant-speed conveyor-type conveying devices to various linear conveying devices that are put to practical use in places other than automobile factories.

[Brief explanation of the drawing]

The drawings relate to embodiments of the present invention, and FIG. 1 is a plan view of a linear conveyance device and a slat conveyor, and FIG.
- ■ Line sectional view, Figure 3 is a vertical cross-sectional rear view of the linear conveyance device and pallet, Figure 4 is a configuration diagram of the control system, Figure 5 is an explanatory diagram including a time chart of conveyance speed, and Figure 6 is transfer control. 2 is a flowchart of the routine. 1. Linear conveyance device, 2. To slat controller 4.
・Pallet, 8. Linear coil, ・Core member,
L...Predetermined distance. Mazda Motor Corporation Figure 4

Claims (1)

[Claims] (1) A control method for transferring a pallet from a conveyor-type transport device that transports a pallet for workpiece transfer at a constant speed to a linear transport device that transports the pallet using a linear motor, the front end of the pallet in the transport direction being The linear conveyance device is activated to a predetermined operating state from the reference start timing when a predetermined transfer start position on the linear conveyance device is reached, and the conveyance distance of the pallet after the reference start timing is determined in real time, and the conveyance distance of the pallet is determined in real time. Linear conveyance characterized in that when a predetermined distance is reached and the conveyance speed of the linear conveyance device becomes approximately equal to the constant speed conveyance speed of the conveyor-type conveyance device, control of predetermined speed characteristics for the linear conveyance device is started. A method of controlling transfer to a device.