JPS60128514A - Positioning device of mobile body in carrier device - Google Patents

Abstract

PURPOSE:To attain highly accurate positioning by arranging a stator of a linear induction motor and a linear pulse motor at the stop position and fitting a rotor of the linear pulse motor. CONSTITUTION:A work station 2 (2a, 2b) is arranged along a free roller conveyor (1a, 1b) so as to install an automatic machine or the like. The linear pulse 3 (3a, 3b) comprising a slider 4 (4a, 4b) and a scale 5 (5a, 5b) and a stator 7 (7a, 7b) of the linear induction motor are arranged between the conveyors 1 and the pallet 10 on which an object to be carrier 9 is guided and moved. A code plate 11 is fitted to the lower face of the pallet 10 and the reflecting plate 11a is provided. Moreover, detectors 12, 13 are provided to the upper face of the slider 4, the phases of both detectors are compared by a discriminating circuit so as to discriminate the moving direction of the pallet 10. When the reference position is shifted from the detecting position of the detectors 12, 13, the excitation of the stator 7 is controlled so as to control the moving of the pallet 10.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to conveyance devices and devices used in factories and the like, and particularly to a positioning device for stopping a moving body at a predetermined stop position on a conveyance path.

Conventionally, single-sided linear induction motors (hereinafter referred to as LIMs) have been used as a means of transporting objects on product assembly and processing lines.
A pallet conveying device is known that uses a power source as a power source. This pallet conveyance device includes a free roller conveyor, LIM stators (hereinafter referred to as stators) arranged at multiple locations along the free roller conveyor,
It is placed on this free roller conveyor, and the LIM is placed on the bottom surface.
It consists of a pallet (moving body) on which a two-groove body serving as a movable element is attached, and by appropriately controlling the excitation of the stator described in 611, the pallet is moved to a predetermined position. , to transport objects on pallets.

By the way, in this type of pallet conveying device, when a moving pallet is stopped, it is done by anti-phase braking in which the stator is excited in an anti-phase manner. However, it is difficult to stop the pallet at a predetermined stop position with high positioning accuracy using only antiphase braking.

Therefore, conventionally, a positioning device has been proposed in which the pallet is sufficiently decelerated by anti-phase braking and then stopped at a predetermined stop position using a linear pulse motor 8 (hereinafter abbreviated as LPM). Figures 1 (a) and (b) are a plan view and a side view showing the configuration of a pallet conveying device equipped with such a positioning device. In these figures, 1 is a free roller conveyor, and 2 is a workpiece. Station, 3i! This is a positioning LPM placed in front of the work station 2. This LPM3 is a mover (hereinafter referred to as
The slider 4 is composed of a slider 4 (hereinafter referred to as a scale) and a stator (hereinafter referred to as a scale) 5.
A rod 6 protruding from the top surface of the rod 6 and a rod drive mechanism for moving the rod up and down are incorporated. Also,
7 is a stator of the LIM for deceleration, 8 is a pallet placed on the free roller conveyor 1, and the lower surface of the pallet 8 is a primary plate made by superimposing a J aluminum plate and an iron plate, which serve as the mover of the LIM for deceleration. A square hole 8a is formed into which the conductor is attached and into which the upper end of the rod 6 is fitted. Further, 9 is an object to be transported placed on the pallet 8. In addition, in Figure 1 (a) and (b),
Only the steel tough LIM for deceleration is shown, and the LIM for acceleration is shown.
The stator is not shown.

Further, in FIG. 1(b), illustration of the seven-reeler roller conveyor 1 on the near side is omitted. Then, the pallet 8 moving at high speed on the free roller conveyor 1 in the direction of the arrow shown in the figure reaches the position indicated by the dashed line C in the figure while being decelerated by the traveling magnetic field in the direction of the arrow B generated by the stator 7. Next, the stator 7 is demagnetized by detecting this valent 10 by a detection means such as a rimming switch, and at the same time, the upper end of the londro is fitted into the square hole 8a of the pallet 80. Thereafter, the slider 4 of the LPM 3 moves a predetermined step in the direction indicated by the arrow, and pulls the pallet 8 to a predetermined position indicated by the dashed-dotted line n. thus,
A pallet 8 and a transported object 9 are positioned relative to the station 2.

However, such a positioning device has a problem in that when the weight of the transported object becomes large and an overload is applied to the LPM 3, a so-called step-out phenomenon occurs, resulting in a decrease in positioning accuracy. Furthermore, since the slider 4 and the pallet 8 are mechanically coupled, there are problems in that precision is poor and shocks occur during coupling.

In view of the above-mentioned circumstances, this invention eliminates the tax adjustment phenomenon, enables high-accuracy positioning, and furthermore, eliminates the problem of poor accuracy caused by mechanical coupling, which was a conventional problem, and This provides a positioning device that can remove shocks, etc., and fixes a linear induction motor to a detected element attached to a moving body and a predetermined stopping position on the conveyance path to stop the moving body. a linear pulse motor disposed together with the movable element; a detection means attached to the movable element of the linear pulse motor for detecting the detected element; a seventh control means for moving the movable element of the linear pulse motor by a predetermined step; and controlling excitation of the stator of the 1J near induction motor based on the detection signal of the detection means;
The present invention is characterized by comprising a second control means for causing the movable body to follow the movement of the movable element of the linear pulse motor.

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 2(a) and 2(b) are a plan view and a side view showing the mechanical configuration of a pallet conveying device equipped with a positioning device according to an embodiment of the present invention. Illustration of the free roller conveyor 1b on the side is omitted. In these figures, 1a and 1b are free roller conveyors arranged parallel to each other along the conveyance path. Also, 2a.

Reference numeral 2b denotes work stations arranged along the free roller conveyors 1a and 1b, each of which is equipped with an automatic machine that performs its own work process. Between the 7-ree roller conveyors 1a and 1b in front of this station 2a, there is an LPM consisting of a slider 4a and a scale 5a.
3a and the stator 7a of the LIM are arranged parallel to the free roller conveyors 1a and 1b, respectively, and similarly,
In front of station 2b are slider 4b and scale 5.
LPM 3b consisting of LPM 3b and stator 7b are respectively arranged. In addition, 1o is a pallet that moves while being guided by free roller conveyors 1a and 1bK on which 9 objects to be transported are placed.
A λ-groove body that serves as a 3J mover is attached. Also,
A rectangular code plate 11 is attached to the lower surface of the pallet 1o at a position vertically facing the sliders 4a*4b so as to match the movement direction of the entire pallet 10 in the operator's direction. On the lower surface of the code plate 11, elongated rectangular reflecting plates 11a, 11a, . . . are mounted at equal intervals in the longitudinal direction of the code plate 11. In this case, the reflecting plates 11a, 11B, . . . are arranged so that their longitudinal directions coincide with the width direction of the code plate 11.

On the other hand, on the upper surfaces of the sliders 4a and 4b, detectors 12 and 13 consisting of a pair of reflective photosensors are attached with their respective detection directions facing upward. It forms a pair with the plate 11 to constitute an incremental linear encoder. On the other hand, at predetermined locations on the left side of each station 2a, 2b, there are reflective photosensors (hereinafter simply referred to as sensors) 14a and 14b for detecting the front edge of the pallet 10 passing over the free rollers la, lb. are arranged respectively. Note that a large number of the above-mentioned work stations 2a and 2b are provided along the free roller conveyors la and lb, but
In FIG. 2, only one adjacent balent 1 is shown, and the valent 10 is conveyed in the direction of arrow A shown in the figure.

Next, the electrical configuration of the positioning device according to this embodiment will be explained with reference to FIG. In FIG. 3, a portion indicated by the symbol M is a circuit provided corresponding to the station 2b, and such a circuit is provided corresponding to each work station. On the other hand, one transport control device 22 is provided for the whole.

In FIG. 3, 13a and 13b are both the aforementioned detectors 1.
These photosensors 13a and 13b are each arranged so as to detect two points separated by a predetermined interval in the longitudinal direction of the lower surface of the code plate 11. When the seven autosensors 13a and 13b respectively detect the reflection plates 11a, 11a, . . . of the code plate 11, they output a human phase pulse AP and a B phase pulse BP to the discrimination circuit 15. This discrimination circuit 15 is the photo sensor 1
The phase of the human phase pulse AP and the B phase pulse BP supplied from 3a and 13b are compared to determine the moving direction of the pallet 10 with respect to the slider 4b. If so, it is determined that the pallet 10 is moving in the right direction (forward direction) in the drawing with respect to the slider 4b, and an addition pulse UP having the same number of pulses as the physiognomic pulse AP is sent to the amplifier terminal of the reversible counter 16. Output to U. Actually, on the contrary, the A phase pulse AP is B
If the phase is delayed from the phase pulse BP, slider 4
It is determined that the pallet 10 is moving to the left (in the opposite direction) in the drawing with respect to b, and a subtraction pulse DP with the same number of pulses as the B-phase pulse BP? It is output to the down terminal of the iT inverse counter 16. The reversible counter 16 sequentially amplifies and counts the addition pulses UP supplied from the discrimination circuit 15 and down-counts the subtraction pulses DP, and outputs the resulting eight count value SP to the subtracter 17. in this case,
The count value SP is the pallet 10 for the slider 4b.
It corresponds to the moving food. The subtracter 17 subtracts the reference value K from the supplied count value SP, and outputs the resulting forward/reverse signal SD to the D/A converter 18. This value is the same as the count value SP obtained when the detector 13 detects a predetermined reference position of the D/A converter 18.
converts the positive/reverse signal SD supplied from the subtracter 17 into an analog positive/reverse voltage signal SA and outputs it to the gate control circuit 19 . This forward and reverse voltage signal 5Ailt fluctuates in response to changes in the relative position of the slider 4b and the pallet 10, as shown in FIG. When the detector 13 on the slider 4b detects the reference position of the code plate 11 (pallet 1o) determined by the reference value mentioned above, the forward/reverse voltage signal SA becomes 0. When the reference position of the code plate 110 deviates from the detection position of the detector 13 by a distance Xi in the positive direction, the forward and reverse voltage signals SA will be deviated from the reference position of the code plate 110 as shown in the figure. is shifted by a distance XI in the opposite direction from the detection position of the detector 13, the positive and reverse voltage signal SA becomes -v1. Gate control circuit 19 is D/A converter 18
It controls the gate of the thyristor 20 based on the forward and reverse voltage signals supplied from the thyristor 7b, and controls the voltage applied to the stator 7b from the 3-phase AC power supply via the thyristor 20.
This controls the excitation of the system cheetah b. in this case,
The gate control circuit 19 is configured so that the supplied positive and reverse voltage signal SA is 0.
The direction and strength of the traveling magnetic field generated by the stator 7b are controlled so that the pallet 1 is constantly detected by the detector 13.
Controls the movement of 0.

Further, the LPM drive control circuit 21 controls the drive of the LPM 3b, and outputs the physiognomic pulse AP from the photosensor 13a.
At the time when the LPM 3b is received, driving of a predetermined step of the LPM 3b is started, and a positioning operation start signal ST is output to the reset terminal R of the reversible counter 16 and the gate control circuit 19. In addition, the LPM drive control circuit 21
When the predetermined step of driving is completed, the slider 4
b to the initial position, and outputs a positioning operation end signal END to the gate control circuit 19. The conveyance control device 22 controls the stator 7a of each part of the pallet conveyance device according to detection signals from the sensors 14a, 14b, . . . and a preset program.

7b, . . . , thereby controlling the pallet 10.
A control signal SC for controlling the excitation of the stator 7b is supplied to the gate control circuit 19. Furthermore, during the period from receiving the positioning operation start signal ST to receiving the positioning operation end signal END, the gate control circuit 19 operates the stator based on the positive and reverse voltage signal strings supplied from the D/A converter 18. In other periods, the excitation of stator 7b is controlled based on the control signal SC supplied from conveyance control device #22.

Next, the process in which the pallet 10 stopped at the station 2a is transported to the station 2b and positioned will be explained with reference to FIGS. 1(a) and 3(b) and FIG. First, the stator 7a is excited in positive phase under the control of the conveyance control device 22 to generate a field 6M traveling in the direction of the arrows shown in FIGS. As a result, the ballen 10, which is stopped at the position indicated by the dashed-dotted line E in the figure, is urged in the direction of the arrow A and begins to move. Thereafter, the pallet 10 moves while being accelerated while receiving the force of the stator 7a, and then moves by inertia while decelerating slightly after leaving the stator 7a.Next, the pallet 10
When it approaches station 2b and reaches the position of the dotted line F shown in the figure, the front edge of the let 10 is detected by the sensor 14b, and this detection signal is supplied to the transport control rack @22. (see FIG. 3), the conveyance control device 22 supplies the gate control circuit 19 with a control signal SC that excites the stator 7b in reverse phase, and thereby the gate control circuit 19 excites the stator 7b in reverse phase.As a result, the pallet 10 is shown in FIG. 2 (a) where the stator 7b is generated (
It receives a braking effect from the traveling magnetic field in the direction of arrow B shown in b), and moves while being decelerated. Next, the pallet 10 moves to a position vertically facing the detector 13, and the photosensor 13a detects the reflector 11B and converts the physiognomic pulse AP into an LP.
When outputted to the M drive control circuit 21, the LPM drive control circuit 21 starts driving the LPM 3b in a predetermined step, and also supplies the positioning operation start signal ST to the reset terminal R of the reversible counter 16 and the gate control circuit 19.

As a result, the reversible counter 16 is reset, and the gate control circuit 19 starts controlling the excitation of the stator 7b based on the forward/reverse voltage signal SA supplied from the D/A converter 18. As a result, the reversible counter 16 is reset. The positioning operation begins. Thereafter, the slider 4b moves in the direction of arrow A shown in FIGS. 2(a) and 2(b), and the baren 10 moves while following the movement of the slider 4b. After the slider 4b moves a predetermined step, it stops at the position indicated by the dashed-dotted line H shown in the figure, and the pallet 1o stops at the position indicated by the dashed-dotted line G shown in the figure. In this way, the baren 10 is positioned at the station 2b. Also, at this point LPM
The drive control circuit 21 outputs a positioning operation end signal END to the gate control circuit 19, and returns the slider 4b to its initial position to prepare for the next positioning operation. Also,
After the gate control circuit 19Fi receives the positioning operation end signal END, the excitation of the stator 7b is controlled based on the control signal SCK supplied from the conveyance control device 22.

Here, the pallet 10 stopped at station 2a
Until it is transported to station 2b and positioned,
FIG. 5 shows the relationship between the position and speed of the baren 10. That is, the pallet 10 is moved at a speed υ by the stator 7a from the position 0 of the station 2a to the position t1, which is a predetermined distance away.
1, then coasts while decelerating slightly between positions it1 and t2, and further accelerates to positions tM and tz~t3.
In between, the stator 7b increases the speed υ2 to 03
is rapidly decelerated to. At this time M:t3, the above-described positioning operation is started, and the pallet 10 moves at the same speed as the moving speed υ3 of the slider 4b, and then stops after being accurately positioned at the position tt4 of the station 2b.

In addition, in the embodiment described above, the pallet 10 is moved on the free roller conveyor 18.1b, but
The pallet 10 may be provided with wheels or rollers, and the pallet 10 may be moved on rails arranged along the conveyance path.

As explained above, according to the present invention, a detected element attached to a moving body and a stator of a linear induction motor are arranged on a conveyance path at a predetermined stopping position where the moving body is stopped. a near pulse motor, a detection means for detecting the detected element n1 attached to a movable element of the i11-equipped linear pulse motor, and a detection means for detecting the detected element; a first control means for moving the child by a predetermined step;
A second control means for controlling the excitation of the stator of the linear induction motor based on the signal output from the calibration detection means and causing the movable body to follow the movement of the movable element of the linear pulse motor is provided. Benefits such as:

- Since the pallet is moved by the LIM during the positioning operation, no load is applied to the LPM, and therefore, even if the number of objects to be conveyed becomes large, tax adjustment phenomena will not occur.

(2) Since the LPM has a positioning accuracy of about ±70 μm, extremely high-precision positioning can be achieved by increasing the detection accuracy of the detection means.

■ The pallet positioning stop position can be arbitrarily set for each LPM step.

(2) It is possible to eliminate the drawbacks of conventional positioning devices, such as poor accuracy due to mechanical coupling and shock during coupling.

[Brief explanation of drawings]

FIGS. 7(A) and (B) are respectively a plan view and a side view showing the configuration of a fLfc pallet conveying device provided with a conventional positioning device, and FIGS. 2(A) and (B) are each an embodiment of the present invention. A plan view and a side view showing the configuration of a pallet conveying device provided with the positioning device according to the example, FIG. Figure 5 shows the relationship between the distance X from the detection position of
The figure is a diagram showing the relationship between the position and speed of the valent 10. 3a, 3b...Linear pulse motor, 4a, 4
b...sura (#-, 5a, 5b...scale, 7a. 7b...stator, 11...co-)"
Board, 12. 13...Detector, 13a, 13b
...Reflection type photosensor, 15...Discrimination circuit, 16...Reversible counter, 17...
...Subtractor, 18...1)/A converter, 19.
...Gate control circuit, 20 ... Thyristor, 21 ... LPM drive control circuit. Applicant Shinko Electric Co., Ltd. Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] a stator of a linear induction motor disposed at a predetermined position on a conveyance path; a moving body having a movable element of the linear induction motor attached to its lower surface; a roller that supports the movable body movably along the conveyance path, and transports a conveyed object placed on the movable body; a detected element, a linear pulse settler disposed at a predetermined stop position of the moving body, a detection means attached to a movable element of the linear pulse motor for detecting the detected element 0i1, and the moving body a first control means for moving the flexible element of the linear pulse motor stepwise to a prescribed position when the linear pulse motor approaches the predetermined stop position; A positioning device for a movable body in a conveyance device, comprising a control means for controlling excitation of a stator of the linear pulse motor and causing the movable body to follow movement of a movable element of the linear pulse motor.