JPS62126413A - Positioning device for moving body in carrying device - Google Patents

Abstract

PURPOSE:To shorten an adjusting time even if the entering speed of a moving body is changed by exciting an electro-magnet again at the passage of the moving body on a stop position after the passage of time corresponding to the entering speed of the moving body detected by a detecting means. CONSTITUTION:When a sensor 20 detects the passage of a pallet 10 during the slow movement of the pallet 10, a controller 22 starts to measure time. When a sensor 21 detects the passage of the pallet 10 at time t2, the controller 22 turns a stator 6b to non-operating status and turns the electro-magnet 16 to excited state. At time t4 after the passage of a prescribed time T1, the electro-magnet 16 is once turned to the non-excited state, and at time t6 after the passage of a time Ta obtained by subtracting the prescribed time T1 and the measuring time ta from a fixed time Tc, the electro-magnet 16 is excited again. The time required for turning the electro-magnet 16 to the non-excited state is extended in accordance with the increase of the entering speed of the pallet 10. Consequently, the pallet 10 is rapidly decelerated independently of the entering speed of the pallet 10 and the adjusting time is shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a conveyance device used in factories, warehouses, etc., and particularly to a positioning device for positioning and stopping a moving object at a predetermined stop position on a conveyance path without contact. Regarding equipment.

“Prior Art” Traditionally, single-sided linear induction motors (hereinafter referred to as LI
A transport device using a drive source (abbreviated as M) as a drive source is known. As shown in FIGS. 3(a) and 3(b), this conveying device is provided along a conveying path, and includes a pair of free roller conveyors 4, 4, each having rollers 2, 2,... It is supported movably along the conveyance path by LIM stators (hereinafter referred to as stators) 6a, 6b, which are disposed at multiple locations and are responsible for generating a traveling magnetic field, and by rollers 2, 2, and so on. The pallet 10 has a secondary conductor 8, which serves as a movable element L and M, attached to the lower surface thereof. Then, by sequentially exciting the plurality of stators 6a, 6b, . . . in positive phase to give thrust in the forward direction to the pallet IO, the pallet IO is accelerated every time it passes above the stators 6a, 6b, . move in the forward direction while being Also,
Pallet I
By applying a thrust force (braking force) in the backward direction to O, the moving pallet lO is decelerated. In this way, by appropriately controlling the excitation of the plurality of stators 6a, 6b..., the pallet 10 is accelerated or decelerated each time it passes above the stators 6a, 6b..., and the stators 6a, 6b...
...runs by inertia in places other than above,
As a result, the transported objects 11 loaded on the pallet IO
It is designed to transport.

According to such a transport device using LIM as a driving source,
Pallet 10 as a moving body and stator 6a as a driving source
, 6b... are always conveyed in a non-contact state, allowing for high-speed conveyance, quiet operation, and zero operation, which were difficult with conventional mechanical conveyance devices using chains, belts, rollers, trolleys, etc. It is possible to achieve maintenance.

In addition, in such a transport device using LIM as a drive source, it is necessary to accurately position and stop the pallet IO with respect to a station where the transported object 11 is processed or loaded and unloaded. However, as a device for positioning and stopping the pallet 10, a non-contact positioning device using an electromagnet as shown in FIG. 4(a) has been proposed. In this figure, summer 2 is a roughly E-shaped movable core, and this movable core!
2 is attached to the lower surface of the pallet 10 with its three protrusions facing downward (see FIG. 3(a)). Further, 14 is a substantially E-shaped fixed core similar to the movable core I2, and is disposed at a predetermined stopping position on the conveyance path with its three protrusions facing upward, and is located at the center of the fixed core 14. A coil 15 is wound around the protrusion. The fixed core 14 and coil 15 constitute an electromagnet 16. When the electromagnet 16 is energized while the pallet IO is traveling at low speed due to inertia from the left to the right in the drawing in FIG. The respective protrusions are positioned and stopped at vertically opposing positions.

By the way, in the above-mentioned positioning device using the electromagnet I6, the pallet 10 can be positioned in a non-contact state, so the quiet operation and maintenance-free operation, which are the features of the conveying device using LIM, are not hindered. On the other hand, even if the electromagnet 16 is energized, the pallet 10
The pallet 10 does not stop immediately, but instead vibrates back and forth repeatedly and then stops, and the time it takes for the pallet 10 to stop, that is, the so-called settling time, is disadvantageous. That is, electromagnet 1
6 is excited, a so-called centripetal force acts on the movable core 12 in a direction that tends to reduce the displacement relative to the fixed core 14, and this centripetal force is expressed by the dashed-dotted line g,
, c2, within a certain range of displacement of the movable core 12 with respect to the fixed core 14, the larger the absolute value of the displacement, the greater the displacement, and becomes O when the displacement becomes 0.

On the other hand, when the pallet 10 is coasting, the pallet IO is gradually decelerated due to, for example, the frictional force generated between the rollers 2, 2, and their bearings. As a result, the pallet IO gradually decelerates due to the action of the frictional force, etc., as shown by the solid line e in FIG. It stops at the position where the centripetal force and centripetal force match. Therefore, especially in the configurations shown in FIGS. 3(a) and 3(b), when the frictional force generated between the rollers 2, 2... and their bearings is extremely small, or when the moving body is used for magnetic levitation, In a magnetically levitated conveyance device that is equipped with an electromagnet and moves a movable object in a suspended state from a conveyance path, the settling time becomes extremely long.

"Problems to be Solved by the Invention" Therefore, as shown in FIG. 3 (b), the pallet IO is
A sensor I9 for detecting passage of the pallet IO is provided at a position separated by a distance in the direction opposite to the traveling direction of the pallet IO, and
As shown in Figures (A) to (C), the sensor 19 is connected to the pallet I.
At the time when the passage of O is detected (time t), the stator 6b is put into a non-operating state (OF At the point in time (time b) when the pallet 10 begins to move in the backward direction after passing through the displacement O), the electromagnet 16 is de-energized and the pallet 10 is moved in the backward direction by inertia. It is conceivable to position the electromagnet 16 by energizing it again at the time of passing the stop position (time 11). According to this, conventionally,
As shown by the dotted line in FIG. 5(A), the longitudinal vibration of the pallet 10 that occurs during positioning is rapidly reduced as shown by the solid line in the figure, so the settling time can be shortened. . However, if the moving speed of the pallet 10 changes, for example if the approach speed of the pallet IO becomes faster, the time of the song when the displacement of the pallet IO becomes 0, as shown by the two-dot chain line in FIG. At t3, the electromagnet 16 is excited, and as a result, the vibration of the pallet IO is not suppressed, resulting in a drawback that the settling time cannot be shortened.

This invention has been made in view of the above-mentioned circumstances, and has an object to be able to position a moving object in a non-contact state, and to shorten the settling time when the approach speed of the moving object changes. It is an object of the present invention to provide a positioning device for a movable body in a conveyance device.

[Means for Solving the Problems] The present invention includes a movable iron core attached to a movable body moving along a conveyance path, and a movable iron core disposed at a stop position for stopping the movable body on the conveyance path. an electromagnet that magnetically attracts an iron core; a detection means that is provided at a predetermined distance from the stop position in a backward direction of the moving body and detects passage and speed of the moving body; and detection of the detection means. control means for controlling excitation of the electromagnet based on the result; the control means excites the electromagnet at the time when the detection means detects passage of the moving body; and when a predetermined period of time has elapsed from this time When the moving body starts moving backward after passing the stop position, the tram electromagnet is de-energized to move the moving body backward by inertia, and the moving body detected by the detection means is The present invention is characterized in that the electromagnet is re-energized when the movable body passes the stop position after a period of time corresponding to the approach speed has elapsed.

"Operation" The electromagnet is excited when the detection means detects the passage of the moving object, and when the moving object passes the stop position and begins to move in the backward direction after a predetermined period of time has elapsed from this point, the electromagnet is activated. It is considered de-energized. As a result, the moving body moves in the backward direction due to inertia. Furthermore, when the movable body passes the stop position after a period of time corresponding to the approach speed of the movable body detected by the detection means has elapsed, the electromagnet is re-energized and positioned, thereby shortening the settling time.

"Embodiments" Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a configuration when an embodiment of the present invention is applied to the conveying device shown in FIGS. 3(a) and 3(b). In this figure, 20.21 is a sensor provided along the free roller conveyor 4.4 to detect the passage of the pallet 10, and is composed of a reflective photosensor or the like. These sensors 20 and 21 are provided at positions separated by a distance ML from a positioning stop position (station) of the pallet IO in a direction opposite to the traveling direction of the pallet IO. Further, 22 is a stator 6a,
6b... and a controller that controls the excitation of the electromagnets 16.16, and this controller 22 receives a detection signal from a sensor (path shown) that detects the passage of pallets 10 provided at multiple locations on the free roller conveyor 4.4. In addition to the function of controlling the excitation of each stator 6a, 6b... based on the excitation of the stator 6b and electromagnet 16.1 based on the detection signals from the sensors 20 and 21 as described below.
It has a function to control the excitation of 6.

Next, in the configuration described above, the palette! 0 as electromagnet 16
Figure 2 (
This will be explained with reference to (a) to (c).

Figure 2 (a) shows the displacement of the pallet 1° in the forward and backward direction during positioning, and Figure 2 (b) shows the operating state of the electromagnet 16 when the pallet IO approaches the Figure (c) shows the operating state of the electromagnet 16 when the pallet 10 enters at a high speed.

First, a case will be described in which the speed at which the pallet 10 approaches the station is slow. In this case, the pallet IO is displaced as shown by the solid line in FIG. 2(a). That is, when the pallet IO approaches the station and is moving at low speed under the thrust from the stator 6b,
At the time when the sensor 20 detects the passage of the pallet IO (time E), the controller 22 starts measuring time. Next, the controller 22 measures time ta, and when the sensor 21 detects whether the pallet 10 has passed at time t2, the controller 22 moves the stator 6b
is inactive and the electromagnet 16 is energized! r3(
ON). Then, when a predetermined time T1 has elapsed from time t2 (time t4), the electromagnet 16 is once de-energized (OFF), and then from a predetermined time Tc to a predetermined time T.
, and when the time Ta obtained by subtracting the measurement time ta has elapsed (time to), the electromagnet 16 is brought into the excited state again. Here, the relationship between each time is as shown in the following equation.

Ta=Tc-(T++ta) --------(:
I) By doing this, the operation of the pallet IO after time L4 changes from the state shown by the dotted line in Fig. 5(a) to the state shown in Fig. 2(a).
b), as shown by the solid line, that is, after time t4, the pallet IO gradually moves in the backward direction toward zero displacement due to inertia, and at the time clock 〇 when the pallet IO reaches almost zero displacement, the electromagnet 16 is turned off again. The energization causes the pallet IO to be positioned, thereby quickly settling the vibrations of the pallet IO.

Next, a case where the pallet IO enters the station at a high speed will be described. In this case, the pallet IO operates as shown by the two-dot chain line in FIG. 2(a). That is, when the pallet 10 approaches the station and the sensor 20 detects the passage of the pallet IO (time 1)
．． ), the controller 22 starts measuring time. Next, the controller 22 measures time tb, and when the sensor 21 detects the passage of the pallet 10 at time L3, the controller 22 measures the time tb.
is in a non-operating state, and the electromagnet 16 is in an energized state (ON).
). In this case, the measurement time tb is shorter than the measurement time (a) when the approach speed of the pallet 10 described above is slow.Then, when the predetermined time T1 has elapsed from the time t (
The electromagnet 16 is once de-energized at 7g (oFF).
Then, when the time Tb obtained by subtracting the predetermined time T1 and the measurement time tb from the fixed time Tc has elapsed (time 11)
Then, the electromagnet 16 is brought into an excited state again. Here, the relationship between the above respective times is as shown in the following equation.

Tb= Tc (T ++ tb) −・・
-(2) Since the measurement time ta>tb, the relationship Ta<Tb can be derived from equations (1) and (2) above.

In other words, the faster the pallet 10 enters, the longer it takes for the electromagnet 16 to be in the de-energized state. As a result, as in the case where the approach speed of the pallet 10 is slow, from time t onward, the pallet 10 gradually moves in the backward direction toward the displacement O due to inertia, and the pallet 10 has a displacement of almost 0.
The electromagnet 16 is excited and positioned at a time L7 just before , and the vibration of the pallet IO is therefore quickly stabilized.

According to the embodiment described above, the vibration of the pallet 10 in the longitudinal direction that occurs during positioning is rapidly reduced regardless of the approach speed of the pallet IO, and the settling time is shortened.

Incidentally, in the embodiment described above, the times Ta and Tb for re-exciting the electromagnet 16 are calculated from the above equations (1) and (2), but the measurement time t is not limited to this.
Of course, the optimal times Ta and Tb may be calculated based on other calculation formulas using a and tb as variables.

"Effects of the Invention" As explained above, according to the present invention, a movable iron core attached to a movable body moving along a conveyance path, and a movable iron core disposed at a stop position for stopping the movable body on the conveyance path. , an electromagnet that magnetically attracts the movable iron core; a detection means that is provided at a predetermined distance from the stop position in a backward direction of the movable body and detects passage and speed of the movable body; and a control means for controlling the excitation of the electromagnet based on the detection result of the means, the electromagnet is excited when the detection means detects passage of the moving object, and after a predetermined period of time has elapsed from this point, the moving object stops. When the moving body begins to move backward after passing through the position, the stationary magnet is de-energized and the moving body is moved in the backward direction by inertia, and a time corresponding to the approach speed of the moving body detected by the detection means is Since the electromagnet is re-energized when the moving object passes the stop position, the vibration in the direction of the operator that occurs in the moving object during positioning operation is suppressed, regardless of the moving object's approach speed, and the settling time is reduced. The effect is that the time period can be shortened.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.
FIGS. 2(a) to 2(c) are diagrams for explaining the operation of the same embodiment, and FIG. 2(a) is a graph showing the displacement of the pallet 10 in the forward and backward direction during positioning, and FIG. Figure 2 (
B) is a timing chart showing the operating state of the electromagnet 16 when the pallet 1O approaches at a low speed; FIG. 2(C) is a timing chart showing the operating state of the electromagnet 16 when the pallet 10h approaches at a high speed; Figures 3 (a) and (b) are a front view and a plan view showing the configuration of a conventional transport device using a LIM as a drive source, and Figure 4 (a) is a front view showing a schematic configuration of a positioning device using an electromagnet. Figure, Figure 4 (
B) is a graph for explaining the operation of the positioning device,
5(a) to 5(c) are diagrams for explaining the operation of the conventional positioning device that aims to shorten the settling time.
Figure (A) is a graph showing the displacement of pallet IO, Figure 5 (
5(b) is a timing chart showing the operating state of the electromagnet 16, and FIG. 5(c) is a timing chart showing the operating state of the stator 6b. 4...Free roller conveyor, 6b...
・Stator, IO...Pallet (mobile object), 1
2...Movable core (movable iron core), 14...
・Fixed core, 15... Coil, 16...
Electromagnet, 19.20...Sensor (detection means),
22... Controller (control means).

Claims (1)

[Claims] a movable iron core attached to a movable body moving along a conveyance path; an electromagnet disposed at a stop position for stopping the movable body on the conveyance path and magnetically attracting the movable iron core;
a detection means provided at a predetermined distance in a backward direction of the movable body from the stop position and detects passage and speed of the movable body; and controlling excitation of the electromagnet based on a detection result of the detection means. and a control means for exciting the electromagnet at the time when the detection means detects passage of the moving object, and after a predetermined time has elapsed from this point, the moving object passes the stop position. Later, when the moving body starts to move in the backward direction, the electromagnet is de-energized, the moving body is moved in the backward direction by inertia, and a time corresponding to the approach speed of the moving body detected by the detection means has elapsed. A positioning device for a moving body in a conveying device, characterized in that the electromagnet is re-energized when the moving body passes the stop position.