JPS61257814A - Synchronous control device for conveyors - Google Patents

Abstract

PURPOSE:To enable the deviation in position between articles placed on synchronous conveyors to be compensated stably with the sufficient response performance provided by changing the control gain value in controlling the conveyors while the difference in speed between No.1 and No.2 conveyors is taken into consideration. CONSTITUTION:The deviation in position (n1-n2) between No.1 and No.2 traveling conveyors, both of them are arranged in parallel with each other, is detected by a position deviation detecting circuit 56. Meanwhile, the difference in speed between both traveling conveyors is detected by a speed difference detecting circuit 58, and is inputted into a gain computing circuit 60. After the control gain has been computed by the gain computing circuit, the conveyors are controlled with the large control gain applied so as to obtain the sufficient responsiveness for synchronization in case that the difference in speed is large, and the conveyors are also controlled with the small control gain applied so as to obtain synchronization where the priority is given to stabilization in case that the difference in speed is small. This configuration enables both No.1 and No.2 traveling conveyors to be controlled so as to be synchronized accurately and stably with the sufficient responsiveness provided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a conveyor synchronous control device, particularly an improvement in which conveyors are operated synchronously based on positional deviations of workpieces conveyed on a first conveyor and a second conveyor. This invention relates to a synchronous control device.

[Prior Art] In an automobile assembly device, the body of the automobile is supported on a first traveling conveyor, and the device for attaching parts such as an engine is attached to a second traveling conveyor. Parts such as an engine are attached to the car body while both traveling conveyors are operated synchronously.

By the way, in the assembly apparatus operated synchronously in this manner, the position of the body often changes when the first traveling conveyor supports the vehicle body. For this reason,
Even though both conveyors are synchronized, the reference positions between the body and the parts mounting device tend to deviate, and it is impossible to assemble the engine to the body as is.

For this reason, devices have conventionally been known that compensate for such displacement and synchronously control both traveling conveyors, and this synchronous control device controls the body supported on both traveling conveyors and the parts attached to the device. A relative positional deviation with respect to a reference position between the two is detected, and a DC motor for driving the conveyor is servo-controlled to compensate for this positional deviation. By doing this, even if there is a relative positional deviation between the articles on the synchronous conveyor, these articles can be attached without any problem, and work efficiency can be improved.

[Problems to be Solved by the Invention] However, conventional synchronous control devices compensate for such positional deviation between articles by using a control function whose gain is controlled to a constant value regardless of the amount of positional deviation. I was going.

For this reason, if the control gain is set to a large value, the control system is likely to vibrate, and although the control response is improved, stable control cannot be performed, and if the control gain is set to a small value, the control system Although stability is improved, there is a drawback that responsive control cannot be performed to the occurrence of positional deviation between parts.

[Object of the Invention] The present invention has been made in view of such conventional problems, and its purpose is to compensate for misalignment between articles on a synchronous conveyor with good responsiveness and stability. The object of the present invention is to provide a conveyor synchronous control device that is possible.

[Means for Solving the Problems 1] The synchronous control device of the present invention operates a first traveling conveyor and a second traveling conveyor in synchronization, and a first workpiece conveyed by the first traveling conveyor; Assembly with a second workpiece conveyed by a second traveling conveyor is performed at a predetermined reference position.

The characteristic features include: a positional deviation detection means for detecting the relative positional deviation of the first and second workpieces conveyed on the first and second traveling conveyors; A differential speed detection means detects the differential speed with the traveling conveyor, and if the differential speed is large, a large control gain is calculated and output,
gain calculating means for calculating and outputting a small control gain when the differential speed is small; multiplying the positional deviation by the control gain to obtain deviation control data, and controlling the first and second traveling conveyors based on this deviation control data; and a control means for controlling relative speed of and compensating for positional deviation.

[Function] With the above configuration, according to the present invention, when the differential speed of the second traveling conveyor with respect to the first traveling conveyor is large, a relatively large control gain is used to correct the positional shift of the workpiece. On the other hand, if positional deviation compensation can be performed with good responsiveness, and the positional deviation of the first and second workpieces becomes smaller, and the differential speed between the conveyance speeds of the first and second travel lines becomes smaller, , highly stable positional deviation compensation can be performed using a relatively small control gain.

As described above, according to the present invention, not only the positional deviation deviation of the first and second workpieces conveyed on the first and second traveling conveyors, but also the differential speed between the first and second traveling conveyors can be calculated. By taking into consideration the positional deviation compensation, the positional deviation compensation can be performed with good responsiveness and stably, making it possible to perform highly accurate synchronous operation control.

[Example] Next, preferred embodiments of the present invention will be described based on the drawings.

FIG. 2 shows a preferred embodiment in which the apparatus of the present invention is applied to an automobile assembly line, in which a first traveling conveyor 12 is provided on the floor 10 of the automobile assembly factory. This first running conveyor 12 is formed as an underfloor running conveyor stored in a duct on the floor surface 10,
The car body 14 (first workpiece) is being conveyed at a predetermined pitch.

A second running conveyor 2 is parallel to this first running conveyor.
0 is set. This second traveling conobear 20 is
A ■-shaped seal is attached to the ceiling beam of the assembly factory in parallel with the first traveling conveyor 12, and the conveyor is formed as an overhead traveling conveyor that drives a synchronized table 1124 along this I-shaped rail 22.

Then, this synchronized cart 24 is moved to the first traveling conveyor 12.
The device 26 operates synchronously with the vehicle body 14 transported by the vehicle body 14, and the parts held on this truck 24 are attached by a device 26.
At step 4, predetermined automobile parts (second workpieces) are attached.

In this embodiment, by controlling the vehicle conveyance speed of the first traveling conveyor 12 to be constant and controlling the traveling state of the synchronized cart 24, the first and second traveling conveyors 12
and 20 are synchronously controlled.

FIG. 3 shows a detailed configuration of the second traveling conveyor 20 and a preferred embodiment of its synchronous control device.

In the embodiment, the synchronous truck 24 is suspended from the I-shaped rail 22 by a pair of running wheels 30° 32 fixedly mounted on the truck body 28, and one of the running wheels 32 is driven by a timing belt 36 by a DC motor 32. ．． The vehicle travels on the I-shaped rail 22 by being driven via the speed reducer 38.

Therefore, the synchronization cart 24 is aligned with the traveling position of each vehicle body 14 conveyed on the first traveling conveyor 12, and the synchronization $11 is adjusted.
1! If you do this, you can easily attach the parts on the synchronization trolley 24! 26 makes it possible to reliably attach desired parts to the vehicle body 14.

In order to perform such synchronous control, the synchronous carriage 24 is provided with a rotary encoder 40 for absolute position detection. outputs an addition pulse, and outputs a subtraction pulse when tracking to the left in the figure. Hence this enconida.

Synchronous trolley 2 by counting 40 output pulses
It becomes possible to accurately detect the absolute value of 4.

In addition, in order to detect the position of each vehicle body 14 conveyed by the first traveling conveyor 12, the line conveyor 12
A rotor 42 is brought into contact with the conveyor chain, and the rotation of the rotor 42 is detected using a rotary encoder 44. A photoelectric switch 46 is provided at a predetermined reference position of the first traveling conveyor 12 to detect when the vehicle body 14 passes through the reference position.
The pulse of the rotary encoder 44 is detected from the time when the vehicle body 14 is detected to have passed the reference position.

By doing so, the transport position of the vehicle body 14 can be detected accurately.

Therefore, in this way, based on the position of the synchronizing table 1124 detected by the rotary encoder 40 and the conveyance position of the vehicle body 14 detected by the rotary encoder 44, it is possible to prevent positional deviation between the two. The rerunning conveyors 12 and 20 may be synchronously controlled.

In order to perform such synchronous control, the detection outputs of the rotary encoders 40, 42 and the photoelectric switch 46 are input to a synchronous control device 50, respectively.

A preferred embodiment of this synchronous control device 50 is shown in FIG. In the embodiment, the rotary encoder 40
The signal output from the up/down counter 52 is counted by the up/down counter 52 and output as a detection signal n2 representing the absolute position of the synchronized carriage 24. Further, the signal output from the other rotary encoder 44 is counted by a counter 54 and is a position detection signal n of the vehicle main body 14 being conveyed.
Output as 1.

Here, since the counter 54 starts its counting operation at the same time as the photoelectric switch 46 detects passage of the vehicle body 14 being transported through the reference position, the output signal n1 from the counter 54 is
This is a position signal representing the relative position of 4.

In this way, the device detection signals nl and nl constituted by the counters 52 and 54 are supplied to the positional deviation detection circuit 5.
6, and the relative positional deviation deviation (nl - nl) between the two is detected here.

Therefore, the positional deviation deviation (nl
By synchronously controlling the first and second traveling conveyors 12 and 20 so that -nl) becomes O, the vehicle body 14 conveyed on the first traveling conveyor 12 and the synchronized cart 2
4, the relative position of the component mounting device 4 accurately matches the relative position with the device 26, making it possible to accurately assemble the component onto the vehicle body 14.

A characteristic feature of the present invention is that in addition to the positional deviation deviation (nl nl) detected in this way, the differential speed (Vl - V2) between the first and second traveling conveyors 12 and 20 is detected. The object of the present invention is to variably control the magnitude of a control gain for synchronous control based on the differential speed. In other words, when the detected speed difference is large, a large control gain is used to perform synchronous control with good responsiveness, and when the detected speed difference is small, a small control gain is used to prioritize stability. Performs synchronous control.

In order to perform such synchronous control, the device of the present invention uses the first
It has a differential speed detection circuit 58 that detects the differential speed between the second traveling conveyor and the second traveling conveyor.

This differential speed (Vl - V2) is calculated by differentiating the output of the counter 54 to calculate the transport speed V of the first traveling conveyor 12, and by differentiating the output of the counter 52 and calculating the conveyance speed V of the first traveling conveyor 12.
It is obtained by calculating the transport speed v2 of , and subtracting both speeds obtained in this way.

In this embodiment, since the conveyance speed 1 of the first traveling conveyor 12 is constant, the differential speed detection circuit 5 of the embodiment
In 8, the speed (1) is set in advance, and the output of the counter 52 is differentiated using a differentiator to calculate the speed (2) of the synchronous carriage 24. Then, subtract ■2 from V obtained in this way to obtain the differential speed, and this differential speed (vl
-V2) is input to the gain calculation circuit 60.

This gain calculation circuit 60 calculates and outputs a large control gain when the differential speed is large, and a small control gain when the differential speed is small.

FIG. 4 shows the relationship between the magnitude of the gain G output from the gain calculation circuit 60 of the embodiment and the differential speed. As is clear from the figure, when the differential speed is small, the When the control gain G1 differential speed is large, a large control gain G is output.

The control gain G output in this way is the positional deviation detection data (
n+ -nl) is input to the multiplier 60, and the multiplier 62 outputs the deviation control data Q (nl - nl) multiplied by this two-person force data.

Therefore, based on this deviation control data G(n+nl), the first traveling conveyor 12 and the second traveling conveyor 2
By performing periodic control of 0, when the differential speed is large, synchronous control is performed with good responsiveness, and as the differential speed becomes smaller, synchronous control is performed that suppresses responsiveness and prioritizes stability.

In this way, according to the present invention, highly responsive and highly accurate synchronous control can be performed.

Furthermore, in this embodiment, the conveyance speed v1 of the first traveling conveyor 12 is added to the deviation control data G (n+ -nl) obtained in this way, and the control data is calculated based on the control data obtained in this way. The running speed of the synchronous trolley 24 is controlled.

That is, in the apparatus of the embodiment, the output n1 of the counter 54 is input to the speed detection circuit 64, and this detected speed 1 is input to the multiplier 66. The multiplier 66 calculates the input speed v
1 is multiplied by a gain K consisting of a predetermined constant, and the multiplied value KV+ is input to the adder 68.

The adder 68 adds the data output from the multipliers 62 and 66, and sends this added data V-G (n+-n2)+KVJ-(1) to the servo driver of the motor 34 via the D/A converter 70. 72.

The servo driver 72 detects the rotation speed of the motor 34 using the tacho generator 74, and determines the speed of the synchronous carriage 24.
2 is input via the D/A converter as the control signal G (n+
-n2) +KVl The motor 34 is servo-controlled to match.

In this manner, in the apparatus of the embodiment, while the first and second traveling conveyors 12 and 20 are being driven, the relative position of the synchronized cart 24 with respect to the vehicle body 14 conveyed on the first traveling conveyor 12 is The traveling speed v2 of the synchronous trolley 24 can be controlled so that the positional deviation becomes O, and the control of the synchronous trolley 24 can be performed accurately with good responsiveness and high stability as described above. .

Further, the device of the embodiment is provided with a steady state operation control circuit 74, which is configured by a device shift deviation (nl −r1
2) is less than the predetermined reference value, that is, the synchronized trolley 2
4 and the vehicle body 14, D/A converts a control signal for halt-controlling the synchronous bogie 24 to the current speed v2 with priority over the control data output from the adder 68. output to the device 70.

In the apparatus of the embodiment, the circuit shown in FIG. 1 is replaced by the CPU 80. D/A converter 70. Up/down counters 52, 54, and I for other input/output
10 interface 82) A memory 84 in which programs and other data shown in FIG. 6 are written and stored.

FIG. 6 is a flowchart showing the operation of the synchronous control device of this embodiment. In the device of this embodiment, when the power of the synchronous control device 50 is turned on, the program shown in the figure is started. RAM area is cleared and the initialization routine is executed.

By inputting various control commands via the I10 interface 82, operations corresponding to these commands are executed.

In an embodiment, this control command is stop.

It consists of four types of commands: forward, backward, and synchronization.

cpua and o are 800H and 99All, respectively, when the input control command is stop, forward, or backward.
, 6661 (all hexadecimal numbers) are input to the D/A converter 70. In the embodiment, the D/A converter 70 has control characteristics shown in FIG. Therefore, when a stop command for stopping is input, the D/AVl conversion P! A 0 volt signal is output from the i70 to the servo driver 72, and the motor 34 is controlled to stop. Similarly, when a forward or backward control command is input, a voltage of +2■ or -2■ is input from the D/A converter 70 to the servo driver 62, and therefore the DC motor 30
The purpose is to rotate forward or reverse at a constant speed and control the synchronous carriage 24 to move forward or backward.

If the control command input via the I10 interface 82 supports synchronous operation, the synchronous control device 50 controls the synchronous truck 24 using the control circuit shown in FIG.

In other words, when a control command for synchronous operation is input,
First, the positional deviation detection circuit 56 detects a positional deviation between the vehicle body 14 and the synchronization truck 24, that is, a positional deviation.

If this positional deviation is less than the reference value of the predetermined rectangle and there is almost no positional deviation, the synchronized cart 24 is held at the current speed (2).

Furthermore, if the detected positional deviation exceeds a predetermined reference value, the vehicle speed detection circuit 58 calculates the differential speed (Vl - V2) between the vehicle body 14 and the synchronous bogie 24, and responds to the detected differential speed. The value of the control gain G to be determined is determined based on FIG. 4 above.

Then, using the gain G obtained in this way, control data (2) shown in the first equation is calculated, and the speed v2 of the synchronized cart 24 is servo-controlled based on this calculated value.

Therefore, the synchronous truck 24 has a running speed such that the positional deviation between the vehicle body 14 and the synchronous truck 24 is O based on the conveyance speed of the first traveling conveyor 12, that is, the conveyance speed 1 of the vehicle body 14. controlled. At this time, if the differential speed (, Vl - V2) between the two transport speeds v1 and 2 is large, a relatively large gain G is used to perform good control with high responsiveness and quickly reduce the positional deviation (nl n2). can be compensated for. Furthermore, as a result of such control,
The differential speed (Vl - V2) decreases, and its positional deviation (
When rll-n2) becomes small, it is possible to perform synchronous control with the most stable gain G while suppressing the responsiveness, making it possible to significantly improve this operating accuracy compared to the conventional one.

In this embodiment, an underfloor conveyor is used as the first conveyor, and an overhead conveyor is used as the second conveyor. However, the present invention is not limited to this, and can be applied to other conveyors. Needless to say, this method is also effective when synchronously controlling.

[Effects of the Invention] As explained above, according to the present invention, the magnitude of the control gain is variably controlled in consideration of the differential speed between the first and second traveling conveyors. It becomes possible to perform synchronous control with good responsiveness, high stability, and accuracy.

[Brief explanation of the drawing]

゛ Fig. 1 4 A block diagram showing a preferred embodiment of the second conveyor synchronous control device according to the present invention, Figs. 2 and 3
Figure 4 is an explanatory diagram of a line conveyor in which the device of the present invention is used, Figure 4 is a characteristic diagram showing the relationship between differential speed and control gain, and Figure 5 is a diagram of the D/A converter 70 used in the device of the embodiment. FIG. 6 is a flowchart showing the operation of this embodiment. 12... First traveling conveyor 14... Vehicle main body 20 as the first workpiece
... Second running conveyor 50 ... Synchronous control device 56 ... Positional deviation detection circuit 58 ... Differential speed detection circuit 60 ... Gain calculation circuit 62 ... Multiplier 64 ... Speed detection circuit 66... Multiplier 68... Adder

Claims (2)

[Claims] (1) Synchronization of the conveyor for assembling the first and second workpieces by controlling the synchronous operation of the first traveling conveyor that conveys the first workpiece and the second traveling conveyor that conveys the second workpiece The control device includes: a positional deviation detection means for detecting a relative positional deviation between the first and second workpieces conveyed on the first and second traveling conveyors; A differential speed detection means for detecting a differential speed, and a calculation output of a large control gain when the differential speed is large,
gain calculating means that calculates and outputs a small control gain when the differential speed is small; and multiplying the position deviation and the control gain to obtain deviation control data, and controlling the first and second traveling conveyors based on this deviation control data. A synchronous control device for a conveyor, comprising: control means for controlling the relative speed of the conveyor and compensating for positional deviation; (2) In the apparatus described in claim (1), the control means adds a value obtained by multiplying the conveyance speed of the first conveyor by a predetermined constant and the above-mentioned deviation control data, and adds the above-mentioned deviation control data to the added value. A synchronous control device for a conveyor, characterized in that the conveyance speed of the second conveyor is controlled based on the conveyance speed of the second conveyor.