JPH0616240A - Stop holding device for magnetically levitated carrier - Google Patents

Abstract

PURPOSE:To provide a device capable of stably controlling the stop holding of a magnetically levitated carrier at a stop point. CONSTITUTION:In a stop holding device, electromagnets 9, 9' are provided in the positions opposed to attracting plates 8, 8', provided at a magnetically levitated body 1, around a desired stop point as the center at the stop time of the body 1, being shifted in such a way that the electromagnet 9 is behind the attracting plate 8, while the electromagnet 9' is in front of the attracting plate 8'. The graduation of a linear scale 10 fitted to the body 1 is read by a position sensor 11, and its pulse signal is counted by a pulse counter 15. On the basis of this signal, the excitation of the electromagnets 9, 9' is controlled by control signals from a stop holding control part 14 through driving circuits 16, 16'. When the body 1 is stopped being shifted from the stop point, the excitation of either electromagnet 9 or 9' is intensified so as to return the body 1 to the stop point, and thus stop holding is performed positively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stop control of a magnetic levitation transportation vehicle, and more particularly to a stop holding device for generating a holding force at the time of stop.

[0002]

2. Description of the Related Art As a transfer device for transferring a moving body in a non-contact manner by a magnetic levitation system, various types have been proposed which utilize the driving force of a linear induction motor.

In such a transporting apparatus, generally, a levitation magnet is provided on a transporting vehicle, and a levitation magnet provided along a traveling path is levitationally maintained so that a predetermined gap is maintained. Stator magnets provided at appropriate intervals on the transport rail apply a transport force in the traveling direction to the next plate to drive the transport vehicle.

[0004] Although there is no great problem in starting or accelerating the transport vehicle with this transport device, various measures are required to stop and hold the transport vehicle at a predetermined stop position.

As means for stopping and holding the transport vehicle at a predetermined stop position, conventionally, a permanent magnet (or a ferromagnetic material) is mounted on the vehicle body, and a ferromagnetic material (or a permanent magnet) is mounted on the permanent magnet (or a ferromagnetic material). It is installed at a position opposite to, and the holding force in the traveling direction is obtained by the suction force of both when the vehicle is stopped.

FIG. 4 shows an outline of a carrier device provided with a stop holding device for such a carrier vehicle. This conventional example is disclosed in JP-A-61-2.
It is disclosed in Japanese Patent No. 44285. Reference numerals 21 and 22 are primary side stators, 23 is a magnet or a permanent magnet, 24 is a secondary side conductor plate, and 25 is a ferromagnetic material.

[0007]

However, in the above-described conventional stop-holding means, the attraction force acting between the permanent magnet and the ferromagnetic material is used, and therefore the displacement of the vehicle body and the pulling force are proportional. It is a so-called spring force and a holding force that can be regarded as a spring force. Therefore, there is a problem that a slight vibration in the front-rear direction continues forever at the time of stopping, and it takes a long time to completely stop.

Further, when the vehicle body passes by, the attractive force between the permanent magnet and the ferromagnetic material acts as a disturbance, causing rolling and the like on the vehicle body, which makes the running posture unstable.

In view of the current state of the stop holding means of the conventional magnetic levitation transfer apparatus described above, the present invention provides two suction means before and after the stop point at which the transfer vehicle should be stopped to control the excitation. It is an object of the present invention to provide a device that can be reliably held at a stop holding point.

[0010]

As a means for solving the above problems, the present invention is to levitate on a ferromagnetic orbit by a levitation electromagnet attached to a vehicle body and drive it by a linear motor.
For magnetically levitated vehicles that travel on orbit with braking force, ferromagnetic plates are attached to the front and rear parts of the vehicle body, and a predetermined distance at the vehicle body stop position on the orbit and at a position facing the ferromagnetic plate. A stop holding electromagnet is installed by shifting it forward and backward, a control circuit for reading the position of the vehicle body and controlling the stop holding electromagnet based on the position information is provided, and controlling the excitation of the stop holding electromagnet when the vehicle is stopped. Thus, the stop holding device for the magnetic levitation transport vehicle is configured to obtain the stop holding force of the vehicle body.

[0011]

In the stop-holding device of the present invention constructed as described above, first, when the vehicle body comes near the stop position, its position information is read, and the stop-holding electromagnet is excited through the control circuit based on the position information. Controlled. The control is to strengthen the excitation of the electromagnet on the side that acts to return the deviation to the stop point if the vehicle body is deviated before or after the stop point, and the advancing direction of the attractive force acting between the suction plate and the electromagnet. Correct the vehicle body position to the stop point by making the components equal.

Even if a deviation occurs again after stopping at the stopping point, the deviation is similarly controlled so that the holding force at the time of stopping can be secured.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a device of a magnetic levitation transportation vehicle equipped with a stop and hold device of the embodiment, and FIG. 2 is a side view including a partial cross section taken along the line II-II of FIG. 1 is a magnetic levitation vehicle, 2 is a track, 3 is a ferromagnetic levitation rail, 4 is a levitation magnet, 5 is a secondary conductor plate of a linear motor, and 6 is a stator of the linear motor. The stator 6 is formed, for example, as a coil wound in an inclined shape in a slot as shown by a dotted line.

Reference numeral 7 is a luggage carrier of the vehicle body, 8 and 8'are ferromagnetic attraction plates, 9 and 9'are electromagnets for stopping and holding, 10 is a linear scale, and 11 is a position sensor using, for example, an optical sensor.

The electromagnets 9 and 9'are attached to the suction plate 8 when the vehicle body is stopped.
8'is installed opposite to each other with a predetermined gap provided at a position corresponding to 8 '. Regarding the positional relationship between the electromagnets 9 and 9'and the suction plates 8 and 8 ', the electromagnet 9 on the front side of the vehicle body is displaced from the suction plate 8 by a predetermined distance, and the electromagnet 9'on the rear side is displaced forward by the same distance.

The linear scale 10 is of a type in which black and white bars such as a bar code are arranged and the position can be displayed by the interval and width of the bars, and the position sensor 11 provides position information without contact from the scale of the linear scale. Is read, and the position sensor 11 outputs a pulse corresponding to the amount of movement of the vehicle body.

FIG. 3 is a schematic block diagram of the stop holding device of the embodiment. The pulse signal read by the position sensor 11 is counted by the pulse counter 15 to detect the vehicle body position. The output of the counter 15 is sent to the transport controller 13 to excite the linear motor. Therefore, the linear motor is driven by the system of 10 → 11 → 15 → 13 → 12 → 6 as in the conventional case.
Stop control is performed.

A stop holding circuit according to the present invention is provided in parallel with the control system of the linear motor. This stop-holding circuit detects the position of the vehicle body by the pulse counter 15 and sends its output to the stop-holding control unit 14 as well, and outputs a signal for controlling the excitation of the electromagnets 9 and 9'installed on the track based on the position signal. It is generated by the control unit 14, and its output is amplified by drive circuits (power amplifiers) 16 and 16 ′, and electromagnets 9 and
It is configured to excite 9 '.

According to the above stop holding circuit, for example, when the vehicle stops ahead of the fixed point, when the excitation of the electromagnet 9'is made stronger than the electromagnet 9, the attraction plate 8'and the attraction plate 8'than the attraction force of the electromagnet 9. Since the attraction force of the electromagnet 9'is larger, the traveling direction component of the latter is also larger, and the vehicle body moves rearward. Both electromagnets 9 when they come to the fixed point,
If the excitations of 9'are made equal, the attraction force before and after becomes equal, and it stops at a fixed point.

The control force at this time can be expressed as follows. The attractive force F of the electromagnet is generally expressed by F≈a (i / x) ² (1). Here, i is the exciting current of the electromagnet, and x is the distance between the electromagnet and the attraction plate.

Assuming that the attraction force between the electromagnet 9 and the attraction plate 8 is F ₁ and the attraction forces of 9 ′ and 8 ′ are F ₂ , the braking force applied to the entire vehicle body is F = F ₁ −F ₂ = A ((i ₀ + Δi) / (x ₀ + Δx)) ² −a ((i ₀ −Δi) / (x ₀ −Δx)) ² (2). Where x ₀ is the distance between the attracting plate and the electromagnet at a fixed point, Δx is the deviation from the fixed point, i ₀ is the balanced current of both electromagnets at the fixed point position, and Δi is when the vehicle body deviates from the fixed position. This is the control current that is passed.

In equation (2), Δx / x ₀ << 1, Δi / i ₀
If << 1, then F≈4a ((i ₀ / x ₀ ² ) .Δi− (i ₀ ² / x ₀ ³ ) .Δx) (3), which is the force acting on the vehicle body of formula (3). Is including Δ
It turns out that it can be controlled by i.

For example, when the vehicle body is at a fixed point (Δx =
0) When the vehicle body tries to deviate from this fixed point, the deviation can be prevented by flowing the control current i ₀ ± Δi to the electromagnet, and this acts as a holding force. In addition,
The above-mentioned Δi is determined by the control unit 14, and generally P, P
I, PID control is used. In addition, the electromagnets 9 and 9'used as a source of the attraction force are de-energized when passing the vehicle. This will prevent the vehicle body from being disturbed.

[0024]

As described in detail above, according to the present invention, when the vehicle body tries to deviate from a fixed point, a force that suppresses the vehicle body is generated, and the force can be controlled based on the holding force. Damping can also be given and vibration at stop is suppressed.

Further, according to the structure of the present invention, since the electromagnet is used as a source of the attraction force, there is an effect that the vehicle body is not disturbed by turning off the excitation when the vehicle passes.

From the above, it is effective to use the present invention for holding a vehicle body at a stop in the field of moving body control such as a magnetic levitation transportation system.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a magnetic levitation transportation vehicle including a stop holding device according to an embodiment.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a block diagram of a stop hold circuit according to an embodiment.

FIG. 4 is a schematic view of a magnetic levitation transportation vehicle including a stop holding unit of a conventional example.

[Explanation of symbols]

 1 magnetic levitation vehicle 2 track 3 levitation rail 4 levitation magnet 5 secondary conductor plate 6 linear motor stator 8, 8'suction plate 9, 9 'electromagnet 10 linear scale 11 position sensor 14 stop hold control unit 15 pulse counter 16, 16 'drive circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location // B61B 13/08 B 9255-3D

Claims (1)

[Claims] 1. A magnetically levitated vehicle that is levitated on a ferromagnetic orbit by a levitation electromagnet mounted on the vehicle body and is driven by a linear motor to obtain a braking force to travel on the orbit. A ferromagnetic plate is attached, and a stop-holding electromagnet is installed by shifting it forward and backward by a predetermined distance at the vehicle body stop position on the track and facing the ferromagnetic plate, and the position of the vehicle body is read and based on the position information. A stop holding device for a magnetic levitation transport vehicle, comprising a control circuit for controlling a stop holding electromagnet, and configured to obtain a stop holding force of a vehicle body by controlling excitation of the stop holding electromagnet when the vehicle is stopped.