JPH01122818A - Conveyer synchronous controller - Google Patents

Abstract

PURPOSE:To improve the precision of synchronism at the synchronous controller of a travel unit not combined with a conveyer, by providing a variation calculating means at the travel unit, and inputting a conveyer movement quantity as a common target, and arranging so that a variation may be sought. CONSTITUTION:A conveyer movement quantity is inputted at a command value generating circuit 30 from an encoder 29. Meanwhile, the encoder 22d of each servo mechanism 22 of a pair of right and left travel units 21, detects the rotation position of each servo motor 22a and an input is made at a servo controller 28. And a variation calculating circuit 31 calculates a variation g1 from the conveyer movement quantity to be inputted from these encoders 29 and a servo motor position to be inputted from encoders 22d, and the output of a feed forward composition calculating circuit 32 is corrected and a control signal is outputted. As a result, the precision of synchronism can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention allows a pair of traveling units, which are not mechanically connected to a traveling conveyor, to be synchronized with each other and synchronized with the conveyor by two systems of servo systems. This invention relates to a conveyor synchronous control device.

Conventional technology A system that moves in synchronization with a conveyor that transports workpieces, such as a car body lifting cart installed on an automobile assembly line, and clamps and positions the workpieces that have been transported by the conveyor to a predetermined position from both sides. Alternatively, in a conveyor system that performs work such as lifting up, a pair of running units installed oppositely on the left and right sides of the conveyor run in synchronization with the conveyor, and the working machines mounted on both running units are operated in synchronization with the conveyor. A conveyor synchronous control device is used to synchronize the operation, and this conveyor synchronous control device is equipped with a servo motor, a servo amplifier that drives the servo motor, and an encoder that detects the rotational position of the servo motor. It has a servo mechanism, a servo controller that controls the servo machine groove, and an encoder that detects the amount of movement of the running conveyor.

Figure 3 shows an example of a conventional conveyor synchronous control device of this type, in which a conveyor (not shown) that conveys a workpiece is
Each of the pair of traveling units 1, 1 arranged opposite to each other on both sides includes a servo motor 2, a servo amplifier 3 for driving the servo motor 2, and an encoder 4 for detecting the rotational position of the servo motor 2. A servo mechanism 5 is provided, and each servo mechanism 5 of both traveling units 1, 1 is connected to two independent servo controllers 6, 6 via a D/A converter 7, respectively.

Each of the servo controllers 6 controls the rotation of the servo motor 2 of one of the servo mechanisms 5 connected to it, and the encoder 4 of the servo mechanism 5 indicates the current position or χ of both servo motors 2, 2. At the same time, the input target rotational position χ and target rotational speed■
From this, the position deviation calculation circuit 9 of each servo controller 6 calculates the deviation L31 (χ-ni) between the current position χR or χ1 of each servo motor 2 and the target rotational position χ.
or 31 (χ-χ,), and the feedforward component calculation circuit 10 calculates an output value of 92V to the D/A converter 7 so that the rotation speed of each servo motor 2 becomes the target rotation speed (■). Further, the deviation 91 (χ-χR) or 91 (χ-χ,), which is the calculated value calculated by the position deviation calculation circuit 9 and the feedforward component calculation circuit 10, and the output value 92V are sent to the processing circuit 11.
The sum obtained by adding dcout R
=! l (χ-χR) 10g2V or dcout 1
=1 (χ-χL)+92V is applied to the D/A converter 7 to individually control the rotation of each servo motor 2, and to synchronize control of the working machines mounted on both traveling units 1, 1. At the same time, the conveyors of both traveling units 1, 1 are synchronously controlled based on data on the amount of movement of the conveyors detected by the encoder 12.

Problems to be Solved by the Invention However, in the case of the above-mentioned conventional conveyor synchronous control device, it is difficult to control each servo system of the pair of travel units 1, 1, which are disposed opposite to each other on the left and right sides of the conveyor. Since two servo controllers 6゜6 are used, there is a difference in the activation timing of each servo controller 6, and a difference in the timing of calculation processing such as acceleration/deceleration points performed inside each servo controller 6. Therefore, there was a problem in that both traveling units 1.1 were not completely synchronized, resulting in a time lag in operation.

In addition, in order to synchronize both traveling units 1.1 with the traveling conveyor, each servo controller 6 requires one encoder 12 for detecting the amount of movement of the conveyor, so two encoders 12. Since the mechanical precision of both encoders 12 and 12 is required so that the amount of movement per pulse of each of 'i2 is the same, the cost is high and there is a problem that it is not suitable for practical use.

Furthermore, both traveling units 1.1 run in synchronization with the conveyor.
In the flyback operation, in which the clamp or lift-up of the workpiece by the work equipment mounted on each traveling unit 1 is released and the workpiece is returned to its original position when the workpiece moves forward to a predetermined position, two servo controllers 6. Since it is necessary to input teaching data separately, there are problems such as complicated operations.

Further, Japanese Patent Application Laid-Open No. 61-257814 describes a conveyor synchronous control device that synchronously controls two conveyors.

This conveyor synchronous control device operates the conveyors synchronously based on the positional deviation of two workpieces conveyed on the first conveyor and the second conveyor, respectively. a positional deviation detection circuit that detects a relative positional deviation between a first workpiece and a second workpiece being conveyed; a speed difference detection circuit that detects a speed difference between the first conveyor and the second conveyor; A calculation circuit that calculates and outputs a large control gain when the speed difference is large, and a small control gain when the speed difference is small, multiplies the position difference and the control gain to obtain deviation control data, and calculates this deviation. The conveyor synchronization control device is characterized by having a control circuit that controls the relative speed of the first conveyor and the second conveyor based on control data and compensates for positional deviation. By taking into consideration not only the positional deviation of the two conveyed workpieces, but also the speed difference between both conveyors, the positional deviation can be compensated for with good responsiveness and stability, and the accuracy can be improved. The purpose is to enable good synchronized operation control.

Therefore, this conventional conveyor synchronous control device has a servo system that controls only one system of conveyors, and the technical issues to be solved are different. If you try to control two systems of servo systems by installing one system, a detection means such as an encoder for detecting the operating position of the conveyor will be installed for each system, so each detection means will require a mechanical The above-mentioned problems arise, such as the requirement for high accuracy.

This invention was made in view of the above-mentioned problems, and by controlling the two systems of servo drive mechanisms based on a common control signal from a single detection means, it is possible to eliminate the difference in startup timing and to In addition to enabling complete synchronization of the operation of the traveling unit and the conveyor,
The purpose of the present invention is to provide a conveyor synchronization control device that facilitates teaching operations such as playback operation to both traveling units.

Means for Solving the Problems As a means for solving the above problems, the present invention provides a pair of traveling units that are synchronized with a conveyor, and a servo drive machine that controls each traveling unit according to the deviation from a target value. In a conveyor synchronous control device with respective grooves,
Each traveling unit is provided with a deviation calculation means for calculating the deviation between the target value and the current value, and a single detection means is provided for detecting the amount of movement of the conveyor, and the output value from the detection means is used for each of the deviation calculation means. The system is characterized in that it is configured so that it can be input as a common target value.

Operation By configuring as described above, each deviation calculation means of a pair of traveling units each having a servo drive mechanism can receive a common output value from a single detection means for detecting the amount of movement of the conveyor. By inputting each target value as a target value, the processing timing of calculation etc. becomes the same. Therefore, unlike when a detection means is provided for each servo drive mechanism of each travel unit, there is no difference in the startup timing of each servo drive mechanism, and the operations of both travel units are completely synchronized and completely synchronized with the conveyor. . Furthermore, since the detection means is single, it is possible to prevent out-of-synchronization caused by product variations in encoders, which would occur when a plurality of encoders are used. Roughly speaking, teaching such as playback operation of both traveling units can be accomplished with a single operation.

Embodiments In the following, a conveyor synchronization control device of the present invention is synchronized with a conveyor that conveys a workpiece, and a traveling unit performs work such as clamping from both sides of a workpiece that has been conveyed by the conveyor and has arrived at a predetermined position to position or lift it up. An embodiment applied to synchronous control will be described based on FIGS. 1 and 2.

The conveyor synchronization control a device is a conveyor 2 that conveys the workpiece.
A pair of traveling units (21, 2) disposed opposite to each other so as to be movable along the conveyor 20 at symmetrical positions across the conveyor 20
It synchronizes the operations of the conveyors 21 and 21 with each other, and controls the demarcation units 21 and 21 to run in synchronization with the conveyor 20. a servo amplifier 22t), a tacho generator 22c that outputs a signal according to the rotational speed of the servo motor 22a, and an encoder 22d that detects the rotational position of the servo motor 22a and outputs it as a pulse signal.
are flooded with ε, respectively, and both servo machines 122.
22 is a central processing unit 23° D/A converter 24. Each is connected to one servo controller 28 equipped with an up/down counter 25, an input/output device 26, and a recording/old device 27. Also, this servo controller 2
8 is also connected to an encoder 29 for detecting the amount of movement of the conveyor 20.

Therefore, the servo controller 28 stores the respective rotational positions of the left and right servo motors 22a, 22a detected by the encoders 22d of the left and right servo mechanisms 22 provided in the pair of left and right traveling units 21.21, and the encoder. The amount of movement of the conveyor 20 detected by the servo controller 29 is sent as a digital signal to the up/down counter 25.
From there, the control signals for each servo motor 22a are converted into analog signals and sent to each servo amplifier 22b.

The servo controller 28 also includes a command value generation circuit 30. which controls the operation of both traveling units 21.21. Position deviation calculation circuit 31. A feedforward component calculation circuit 32 and a processing circuit 33 are provided.

The command value generation circuit 30 receives movement commands (normal rotation, normal rotation,
According to commands such as reverse rotation, conveyor synchronization, playback operation, etc., both servo motors 2
The reference target rotational speed ■ and target rotational position χ are calculated for 2a and 22a. Further, when the movement command is conveyor synchronization, the target rotational speed ■ is the amount of change of the conveyor 20 per unit time determined by the encoder 29, and the target rotational position χ is the movement position of the conveyor 20, so the encoder 29 The output value detected during the movement of the conveyor 20 is given to the servo controller 28 as is.

In addition, the positional deviation calculation circuit 31.31 calculates the difference between the current positions χ and χ1 of the servo motors 22a and 22a obtained by each encoder 22d of the double-bow grooves 22.22 and the target rotational position χ. is multiplied by the gain g1, that is, the deviation 91 (χ-χR) and the deviation 1 (χ-χ,) are obtained.

Roughly speaking, the feedforward component calculation circuit 32.3
2, the D/A converter 2 when obtaining the target rotational speed ■
4. Calculate the output value g2v to 4.

Then, in the processing circuit 33, the deviation 91 (χ - χR) and the deviation 31 (
χ−χ, ) and the output value of 92V are added, and the sum, that is, right side dcOut 3 =? J1 (χ−χR)+92
V and left side dcOut, =1 (χ-χL)+9
2V is determined and applied to each D/A converter 24 to control the rotational positions of both the left and right servo motors 22a, 22a to the target rotational position χ, and synchronize the operation of the left and right travel units 21 and 21. Aim to synchronize the conveyor.

Therefore, as described above, the two servo systems arranged symmetrically are connected to a single servo controller 28 to obtain one common target rotational speed ■ and target rotational position χ, and the D/A converter 24 is By separating the two systems for the first time at the output stage, the arithmetic processing timing inside the servo controller 28 can be perfectly matched.
Perfect synchronization of both traveling units 21.21 and conveyor 2
Complete synchronization with 0 is now possible, and the work equipment is mounted on a pair of left and right traveling units that run in synchronization with the conveyor, and the workpiece being conveyed on the conveyor can be clamped and positioned from both sides, and the workpiece can be clamped from both sides. This makes it possible to carry out tasks such as lifting.

DETAILED DESCRIPTION OF THE INVENTION As described above, the present invention provides a conveyor synchronous control device in which a pair of traveling units synchronized with a conveyor are each provided with a servo drive groove for controlling each traveling unit according to a deviation from a target value. , a deviation calculation means for calculating the deviation between the target value and the current value is provided for each traveling unit, and a single detection means for detecting the movement amount of the conveyor is provided, and the output value from the detection means is calculated for each of the deviations. Input it as a common target value to the calculation means (M, 2
By controlling the system's servo drive sensing grooves based on a common control signal from a single detection means, we have eliminated the start-up timing discrepancy, allowing the operation of a pair of traveling units that are not mechanically coupled. It is possible to completely synchronize the movement of the conveyor, and it can also be completely synchronized with the regular movement of the conveyor.

It also has the effect that teaching of playback operation for the demarcation unit can be completed in a single operation.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention,
Fig. 1 is a block diagram showing the configuration of the conveyor synchronous control device, Fig. 2 is a block diagram showing the servo control system of the conveyor synchronous control device, and Fig. 3 is the control of two servo systems in the conventional conveyor synchronous control device. This is a block diagram showing the following. 20... Conveyor, 21... Traveling unit, 22
... Servo mechanism, 22a ... Servo motor, 22
b...Servo amplifier, 22d...Encoder, 2
3... Central processing unit, 24... D/A converter, 28... Servo controller, 29... Encoder, 30... Command value generation circuit, 31... Position deviation calculation circuit, 32 . . . Feedforward component calculation circuit, 33 . . . Processing circuit, 34 . . . Upper controller. Applicant Toyota Motor Corporation Representative Patent Attorney Yutaka 1) Hisashi Take (one idiot)

Claims (1)

[Claims] In a conveyor synchronization control device in which a pair of traveling units synchronized with a conveyor are each equipped with a servo drive mechanism that controls each traveling unit according to the deviation from the target value, the deviation between the target value and the current value is calculated. A calculation means is provided in each traveling unit, a single detection means is provided for detecting the amount of movement of the conveyor, and the output value from the detection means is input as a common target value to each of the deviation calculation means. A conveyor synchronous control device featuring: