JPS62201715A - Positioning stopper in conveyor - Google Patents

Abstract

PURPOSE:To aim at the prompt stop of a truck, by subtracting such a voltage (current) proportionate to a travel speed from the specified voltage (current) at a period of time when the conveying truck comes nearer to a stopping position but totaling them at a period of time when the truck becomes far off, feeding the primary side of an electromagnet, and generating damping force there. CONSTITUTION:At a period of time when a conveying truck 1 comes nearer to a stopping position 2, restoring force (f) corresponding to voltage V0-K1¦v¦ acts on the truck 1, and at a period of time when the truck becomes far off, restoring force (f) corresponding to voltage V0+K1¦v¦ acts on the truck 1. That is to say, when the truck 1 heads for the stopping position 2, exciting voltage of an electromagnet 6 is held down to low, but when it gets away from it, the exciting voltage of the electromagnet 6 is suddenly increased, whereby such force that pulls the truck 1 back strongly acts on the truck. Therefore, the restoring force (f) acting on the truck 1 varies in an arrow direction on a hysteresis curve with a variation in displacement X of the truck 1 so that energy equivalent to a hysteresis loop area is consumed by the electromagnet 6 and a controller 11 or the like, dispersed and lost to some extent, and the displacement X and the restoring force (f) are focused to zero while describing the hysteresis loop, thus the truck 1 is promptly stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a conveyance device for conveying articles in a factory or the like, and in particular, the present invention relates to a conveyance device for conveying articles in a factory or the like. The present invention relates to a positioning and stopping device that can be stopped at a certain position in a short time.

[Prior Art] In this type of conveyance device, it may be necessary to accurately position and stop the conveyance cart at a station provided on the conveyance path in order to load, unload, or process objects to be conveyed.

FIG. 4 is a perspective view showing an example of such a positioning and stopping device. In this figure, 1 is a transport vehicle, and 2 is a stop position. At this stop position 2, the primary side core 4 of the electromagnet 6 is arranged. This "primary side iron core 4 has a substantially U-shaped cross-sectional shape, and is arranged with the opening facing upward, and an excitation coil 5 is wound around the lower part. On the other hand, on the lower surface of the transport vehicle l, The secondary iron core 3 of the electromagnet 6 is also attached.

The secondary iron core 3 is T-shaped and can be moved through the opening of the primary iron core 4 when the carrier 1 moves. Then, by supplying an excitation current to the coil 5 from the constant voltage power supply 8, the primary side iron core 4 attracts the secondary side iron core 3, and the transport vehicle 1 can be stopped at a predetermined position.

FIG. 5 is a graph showing the relationship between the displacement X from the stop position of the transport vehicle I and the restoring force during the above-mentioned stop.As can be seen from this figure, when the displacement X is positive, the negative A restoring force r acts, and when the displacement X is negative, a positive restoring force r
works. Therefore, the transport vehicle 1 vibrates around the displacement X=0 (equilibrium point), and ultimately comes to a stop at this equilibrium point while being affected by frictional force, air resistance, eddy current resistance, etc.

This type of positioning and stopping device can apply braking force to a moving object and stop it without contact, so compared to devices that use mechanical friction, there is no risk of dust generation and maintenance is easier. There are advantages.

Therefore, if such a positioning and stopping device can be incorporated into a magnetically levitated conveyance device or the like driven by a linear induction motor, a conveyance device that can support, drive, and brake the conveyance vehicle without contact can be realized.
It is extremely convenient for use in clean rooms where generation of dust is extremely disliked.

[Problems to be Solved by the Invention] However, when the above-mentioned non-contact stopping device is incorporated into a magnetically levitated or air levitated conveyance device, the following inconveniences occur. Incorporation into the system has not been realized.

In other words, when the transport vehicle is supported by wheels, etc., an appropriate frictional force exists between the transport vehicle and the transport path, so when the above-mentioned positioning and stopping device is incorporated, this frictional force acts as a vibration damping force. , the transport vehicle can be stopped in a relatively short time. However, when it is incorporated into a magnetic levitation type conveyance device or the like, it takes a long time to stop because no mechanical frictional force is exerted between it and the conveyance path.

This invention was made against this background, and is incorporated into a magnetic levitation type or air levitation type conveyance device, etc.
It is an object of the present invention to provide a positioning and stopping device for a transport device that can stop a transport vehicle within a short time.

Means for Solving Problem L] In order to solve the above problem, the present invention consists of a primary side and a secondary side configured in a non-contact manner, one of which is located at the stop position and the other is located at the stop position. an electromagnet attached to the transport vehicle side, a detection means for detecting a moving direction of the transport vehicle with respect to the stop position and a moving speed of the transport vehicle; During a period when the transport vehicle approaches the stop position, a voltage or current proportional to the moving speed is subtracted from the constant voltage or constant current and is supplied to the primary side of the electromagnet, while during a period when the transport vehicle moves away from the stop position. It is characterized by comprising a control means for adding a voltage or current proportional to the moving speed to a constant voltage or constant current and supplying the same to the primary side of the electromagnet to generate a damping force.

[Function] According to the above configuration, the restoring force becomes small during the period when the transport vehicle approaches the stop position, and the restoring force becomes strong during the period when the transport vehicle moves away from the stop position, so that the displacement of the transport vehicle and the restoring force are reduced. It is possible to quickly stop the transport vehicle while drawing a hysteresis loop as shown in FIG.

[Example code] Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention, and parts corresponding to those in FIG. 4 are designated by the same reference numerals, and their explanations will be omitted.

In this figure, reference numeral 10 denotes a moving speed and moving direction detector for detecting the moving speed and moving direction of the transport vehicle 1 with respect to the stop position 2, and is constituted by a so-called incremental linear encoder or the like. That is, the moving speed and moving direction detector 1O consists of a long slit plate attached to the side of the transport vehicle 1, a pair of photosensors provided on the ground side with this slit plate sandwiched between them, and A phase pulse and B phase output from each photosensor
A discrimination circuit that discriminates the moving direction of the transport vehicle l from the phase difference of the phase pulses, a reversible counter that counts up/down the A-phase pulse or the B-phase pulse based on the discrimination result, and a count value of this reversible counter. Analog signal (
A D/A converter converts the displacement signal into a displacement signal) and the displacement signal shown in Fig. 2 (a) output from this D/A conversion circuit is differentiated to obtain the speed signal SI shown in Fig. 2 (b). a differentiator,
Based on the signs of both the displacement signal and the speed signal Sl, it is determined whether the transport vehicle I is currently approaching or away from the stop position 2, that is, the moving direction with respect to the stop position 2, and the determination result is and a direction determination circuit that outputs a moving direction signal S, and the slit plate has a large number of vertical slits horizontally arranged in two series with different phases, and each of these is detected by the pair of photosensors. It's about to happen. If the sign of the product of the displacement signal and the speed signal S1 is negative, the direction determination circuit determines that the conveyance vehicle I is approaching the stop position 2, and if it is positive, it determines that the conveyance vehicle I is moving away. , outputs a moving direction signal S2 corresponding to this.

On the other hand, the control device 11 has an analog calculation function and a chopper function, and based on the speed signal Sl and the movement direction signal S supplied from the movement speed and movement direction detector 10,
The DC voltage supplied from the power source 12 is controlled and supplied to the coil 5.

That is, the control device 11 controls, based on the speed signal S1 and the moving direction signal S, a constant voltage during the period when the transport vehicle 1 approaches the stop position 2 (periods indicated by ■ and ■ in FIG. 2). While lvl (k is a constant value) is subtracted from v0 to a voltage proportional to the absolute value IVI of speed V, the period during which it moves away (periods indicated by ■ and ■ in Figure 2)
In, constant voltage ■. An analog calculation circuit that adds lvl to a voltage proportional to the absolute value 1vl of the speed V and outputs the control voltage shown in FIG. It is composed of a comparator that compares the control voltage of the above-mentioned analogue calculation circuit, and an FET that turns on/off the DC voltage supplied from the power supply 12 using the output of the comparator as a gate signal.

Next, the operation of this embodiment will be explained with reference to FIG.

First, to help understanding, the electromagnet 6 is always supplied with a constant voltage V.
. We will explain the case where .

In this case, the relationship between the restoring force r acting on the transport vehicle I and the displacement X is shown in FIG.
is a constant). Also, in Fig. 3, the displacement x
=O is the position shown in FIG. That is, this is the position where the midpoint of the primary iron core 4 and the midpoint of the secondary iron core 3 coincide, and the restoring force r applied to the transport vehicle l is zero.

When the transport vehicle 1 is displaced in the positive direction from this position, the restoring force in the negative direction by the electromagnet 6 gradually increases, and the transport vehicle 1 is pulled in the negative direction.

Conversely, when the carrier l is displaced in the negative direction from the position of displacement x=0, the restoring force in the positive direction by the electromagnet 6 gradually increases, and the carrier l is pulled in the positive direction. That is, the transport vehicle 1 vibrates around the displacement X=0.

Next, the operation of this embodiment will be explained. In this embodiment, during the period when the transport vehicle l approaches the stop position 2 (indicated by ■ and ■ in FIG. 3), the constant voltage v0 changes to a voltage proportional to the absolute value m of the speed V. Voltage V minus lvl. −, the excitation voltage corresponding to lvl is applied to coil 5.
supplied to In addition, the period during which it is far away (in Figure 3 ■
and (indicated by ■), constant voltage ■. An excitation voltage corresponding to a voltage Vo+kam obtained by adding a voltage klvl proportional to the absolute value lvl of the speed V to the voltage klvl is supplied to the coil 5. Note that this excitation voltage is determined as described above,
It is formed by the control device 11.

In this case, during the period when the transport vehicle I is approaching the stop position 2, the voltage vo-k is
The restoring force corresponding to ivl = ko(V.

-k, 1vl) During the period when x is acting on the transport vehicle 1 and is moving away from it, the voltage V is as shown in ■ and ■ in FIG. +, the restoring force r=-k corresponding to lvl. (V
.

+ k-vl) x is a transport vehicle! It acts on That is,
When the transport vehicle l heads toward the stop position 2, the excitation voltage of the electromagnet 6 is kept low, and when it leaves the stop position 2, the excitation M1 voltage of the electromagnet 6 is rapidly increased, and a strong force is generated to pull the transport vehicle l back. act.

Therefore, the restoring force f acting on the transport vehicle 1 changes in the direction of the arrow on the curve (hysteresis loop) shown in FIG. 3 as the displacement X of the transport vehicle 1 changes. Energy equivalent to the area of is consumed by the electromagnet 6, control device 11, etc.,
Dissipation loss occurs. Then, the displacement stops quickly.

In the above embodiment, the primary iron core 4 of the electromagnet 6 is provided on the conveyance path side, but the primary iron core 4 may be attached on the conveyance truck l side. Furthermore, instead of controlling with an excitation voltage that corresponds to the speed of the transport vehicle 1, control may be performed with an excitation current that corresponds to the speed.

[Effects of the Invention] As explained above, the present invention provides a stop electromagnet by subtracting a voltage or current proportional to the speed of the transport vehicle from a constant voltage or constant current during a period when the transport vehicle approaches the stop position. On the other hand, during the period when the conveyance vehicle moves away from the stop position, a voltage or current proportional to the speed is added to the constant voltage or constant current and supplied to the electromagnet, so a hysteresis loop is drawn. A restoring force can be obtained, and as a result, vibrations of the transport vehicle near the stop position can be quickly attenuated, and the effect can be obtained that the transport vehicle can be positioned and stopped in a short time.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the configuration of an embodiment of the present invention, and FIG.
Figures (a), (b), and (c) are waveform diagrams of the moving speed and moving direction detector LO and each part of the control device 11 in the same embodiment, and Fig. 3 is a restoration acting on the transport vehicle l in the same embodiment. force f
4 is a perspective view showing the configuration of a conventional positioning and stopping device, and FIG. 5 is a graph showing the relationship between restoring force r and displacement in a conventional positioning and stopping device. ...Speed signal, S, ...
Movement direction signal, 1... Transport vehicle, 2...
・Stop position, 3... Secondary iron core, 4...
...Primary iron core, 5... Coil, 6...
- Electromagnet, lO...Movement speed and direction detector, 11...Control device, 12...Power source. Narrator God w4 Denki Co., Ltd. Figure 1 Sl-m-Speed signal 52--One-shot multiplex'l Cloth key! No.+---m feed 6 fist 2--(Yo-stop A na 1 3---Secondary iron/V 4---IX bolt pair 5-m-coil 6--Electric whetstone 10- -One reed hyperactivity 3u and 4 button Yokoide Masu 11---System m 1 +2---@:R

Claims (1)

[Claims] A positioning and stopping device that stops a conveyance cart moving along a conveyance path at a predetermined stop position is comprised of a primary side and a secondary side configured in a non-contact manner, one of which is located at the stop position. , the other one being an electromagnet attached to the transport vehicle side, a detection means for detecting a moving direction of the transport vehicle with respect to the stop position and a moving speed of the transport vehicle, based on the detection result of the detection means. , during a period in which the carrier approaches the stop position, a voltage or current proportional to the moving speed is subtracted from a constant voltage or constant current and supplied to the primary side of the electromagnet;
control means for generating a damping force by adding a voltage or current proportional to the moving speed to a constant voltage or constant current and supplying the same to the primary side of the electromagnet during a period when the conveyance vehicle moves away from the stop position; What is claimed is: 1. A positioning and stopping device in a conveyance device, comprising: