JPS5817061B2 - Mobile object position detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a moving object position detection device that uses an optical method to detect the self-position of a moving object, such as a magnetically levitated vehicle, which levitates and travels on a track.

Recently, an ultra-high-speed magnetic levitation vehicle system has been developed that uses magnetic force to levitate and propel the vehicle, but in such a system, the self-position of the vehicle in the orbit direction is constantly detected. Then, based on this detection signal, an information signal about the relative position of the traveling vehicle body and the propulsion coil or the speed of the traveling vehicle is created, and this is used to control the current in the propulsion coil and control the operation of the traveling vehicle. There is.

In this method, the information signal for the relative position of the traveling vehicle and the propulsion coil needs to be highly accurate compared to the dimensions of the propulsion coil, for example, about 3 degrees of the length of the propulsion coil in the orbital direction. corresponds to about 30 yen as a practical accuracy.

For example, when using an electromagnetic approach relay that can detect metal objects as a method for detecting the self-position of the vehicle body with such precision, stable operation cannot be obtained because the distance change due to displacement of the vehicle body in the direction perpendicular to the track is large.

For this reason, attempts have been made to use optical position detection methods that are highly accurate and can withstand certain distance changes.

Optical position detection methods can be roughly divided into light-shielding type and reflective type.The former uses a light-shielding plate installed on the track to block light between the emitter and receiver installed on the vehicle. , which converts the presence or absence of light reception to obtain a position detection signal, but this method may not be available due to constraints on the orbit structure.

On the other hand, the latter method detects the presence or absence of reflected light by installing a reflector on the track facing the projector and receiver on the running vehicle, and there are fewer restrictions on the track structure, so this method is often used. The method is applicable.

For such a reflector method, an optically retroreflective reflector (Retro-reflector) is used as a reflector.
There are advantages to using r), and ideas regarding this have already been made.

In both the light shielding type and reflective type mentioned above, the important thing is that a moving body such as a magnetically levitated vehicle assumes a free movement posture within a certain restricted range, so changes in the position of the vehicle body, that is, perpendicular to the trajectory, are important. It is necessary to configure the optical system so that the self-position of the vehicle on the above-mentioned track in the track direction can be detected in any posture regardless of vertical or horizontal displacement that occurs arbitrarily in the direction. be.

For this purpose, the usual method is to scan the light beam over the required range using a scanning method so that the projected light can be effectively projected onto the reflector regardless of the posture and position of the vehicle body, but ultra-high-speed magnetic levitation Very fast like a car (
500 km/h), the amount of movement of the vehicle body during one scan is large, and extremely high speed scanning is required to satisfy the above-mentioned required accuracy.

Scanning is usually performed using a mechanical method such as a rotating mirror or a vibrating mirror, but the scanning speed of this method has its own limitations, and high-speed scanning that satisfies the above-mentioned accuracy cannot be expected with current technology.

On the other hand, a method that can be considered is to always project a band-shaped light beam within a range that corresponds to changes in the attitude of the vehicle body, and to capture the received light by limiting the field of view of the receiver to the range of this band-shaped light beam.
Performance of the reflector used in terms of reflection direction and the reflector;
The relationship between the emitter and the receiver must be carefully set, which is difficult to achieve immediately and cannot be expected.

In view of the above circumstances, the easiest method is to make the effective height or effective width of the reflector large enough to cover the range of changes in the vehicle body. As the length of the track increases, it becomes uneconomical because it requires a large amount of cost, and there are restrictions on the size due to the track structure. )There must be.

For example, when the vehicle body yawing or rolling,
Although the optical axis of the projected light beam may not be perpendicular to the surface of the reflector, it is effective to use the above-mentioned retroreflector.

The purpose of the present invention is to eliminate the drawbacks of the prior art, and to enable the optical system to be maintained reliably at all times, regardless of the attitude displacement of the vehicle body in the direction perpendicular to the track or the partial deterioration of the reflection performance of the retroreflector.
A mobile object position detection device having a highly reliable position detection signal input section is provided.

The main points of the present invention are, first, that a plurality of pairs of light emitters and receivers are arranged on a traveling vehicle at regular intervals so as to cover the range of changes in the motion posture of the traveling vehicle; The optical system is installed so that a position detection signal can be effectively obtained even in the case of Second, in order to prevent position detection errors due to partial deterioration of reflective performance due to partial contamination or alteration of the surface of the retroreflector,
At least one of the light emitter/receiver pairs installed at a position different from the arrangement position of the main detection light emitter/receiver pair is configured to face the retroreflector plate as an auxiliary detection light emitter/receiver pair, and By taking the logical OR of the position detection signals from the detection emitter/receiver pair and the auxiliary detection emitter/receiver pair, the presence or absence of a retroreflector can always be determined using the position detection signals from at least two emitter/receiver pairs. We have created a configuration that effectively realizes the above functions by minimizing the dimensions such as the effective height and effective width of the retroreflector facing the plurality of emitter/receiver pairs as the emitter/receiver device. Features.

Embodiments of the present invention will be described below with reference to the drawings, while also explaining the basic principles of the present invention.

FIG. 1 shows an embodiment of a magnetically levitated vehicle system according to the present invention, and shows a part of a cross section of a track structure and a traveling vehicle in a direction perpendicular to the track.

Here, 1 is a running vehicle, 2 is a track structure, 3 and 3'
are reflectors, which are attached to the side or top surface of the track structure 2, respectively.

Reference numerals 4 and 4' designate light projecting/receiving devices, which are mounted on the vehicle 1 so as to face the reflecting plate 3 or 3', respectively.

The method for determining functions and dimensions will be explained below.

Now, the vehicle 1 floats as it travels, and the limit of the float is limited by an appropriately provided stopper (not shown).

In this case, the height of levitation is the basic height change,
The traveling vehicle 1 assumes various motion postures, which will be explained below with reference to FIG. 2.

Figure 2A shows the pitching of the traveling vehicle 1, and due to the pitching angle δ, the light emitting/receiving device 4 has a height of d shown in the figure in addition to the flying height mentioned above.
only increases.

The opening in Figure 2 shows the rolling of the traveling vehicle 1, and the height and direction of the optical axis of the light emitter/receiver pair 4 change depending on the rolling angle ε, and as a result, the amount of height change of the light beam hitting the reflector plate 3 is e becomes.

Figure 2 (c) shows the yawing of vehicle 1. In other words, this indicates a state where the center is off-centered, and the distance between the light emitter/receiver pair 4 and the reflecting plate 3 changes by f.

When this change is combined with the rolling of the mouth of Figure 2,
As a result, the height changes with respect to the reflecting plate 3.

Figure 2 2 shows a case where the traveling vehicle 1 is deflected due to the attractive force or repulsive force of the magnetic field for magnetic levitation and propulsion, and the height changes due to almost the same reason as the rolling case shown in Figure 2. give.

Although illustration and description are omitted, there may also be deflection of the vehicle body in the direction of travel.

Since the various motion postures and deflections of the vehicle body described above can all be converted into height changes, these are added to the basic height change due to levitation, and are defined as the equirestricted height change amount, H.

FIG. 3 is an explanatory diagram showing the relationship between the arrangement, dimensions, and number of light emitting/receiving device pairs in the light projecting/receiving device 4 according to the present invention, and the dimensions of the reflecting plate.

In the figure, the effective height h' of the reflector is determined by calculating the length d corresponding to the sum of the luminous flux beam radius, dimensional error during the manufacture of the reflector, and error due to optical axis deviation, and then calculating the effective height h' by 2 d from the total length of the reflector.
It is practical to deduct the amount.

This prevents malfunctions due to the above-mentioned errors, and the light beam is completely within the effective range of the reflector and does not escape.

Next, in the light emitting/receiving device 4, a plurality of light emitting/receiving device pairs 4
-1.4-2. ..., 4-n are arranged at regular intervals l in the height direction.

In this case, by setting the value of the interval l to l=h', at least one light projector/receiver pair can operate normally with respect to the reflector plate 3.

With such a spacing l, n emitter/receiver pairs 4-1.4-2
．． .......

In the light emitting/receiving device 4 and the reflecting plate 3 in which 4-n are arranged, the effective operating range with respect to the height change of the light emitting/receiving device 4 is as follows.
As is clear from the positional relationship between the fixed track, the vertical movement of the car body, and the corresponding emitter/receiver that detects it, (n-1
)l+h'.

However, as a practical matter, the reflector 3 and the light emitting/receiving device 4
Since each has installation errors, these errors reduce the effective operating range.

Now, the effective operating range (n-1)l+h' of the light emitting/receiving device 4 with respect to the height change H of the vehicle body described above is H< (n-
1) If hl, 1, and n are selected so that l + h /, one of the n light emitter/receiver pairs can always be in operation despite height changes. .

Here, the smaller h, and therefore h', becomes smaller, the smaller l becomes for a given H, and the larger n becomes.

In order to save the overall cost of the position sensing device, the size of the reflector 3 must be reduced, although this naturally involves an increase in the number of light emitter/receiver pairs.

As already pointed out, reducing the size of the long-distance reflector as much as possible can provide a significant effect that outweighs the cost of increasing the number of light emitters and receivers.

Next, a case will be described in which a known retroreflector is used as the reflector.

FIG. 4 shows the relationship between the retroreflector 5 and the coaxial light projector/receiver 6, and shows that when the vehicle 1 rolls or bends, the normal optical axis g changes to the optical axis k. FIG.

In this case, the amount of change in angle is φ, but the retroreflector 5
Therefore, the optical axes for emitting and receiving light are always on the same axis, and the reflected light can be effectively received by the light receiver.

In fact, since the rolling angle and the deflection of the vehicle body are actually limited to a few degrees or less, the purpose can be sufficiently achieved using a commercially available ordinary retroreflector.

In this case, since the light emitting and receiving axes are the same, coaxial type emitters and receivers are desirable, but this can be easily realized using a well-known coaxial type emitter/receiver pair such as one using a convex reflector or a half mirror. be able to.

The above is an explanation of the basic principle and embodiments of the main detection light emitter/receiver pair in the first half of the present invention.Using this principle, an embodiment of the auxiliary detection light emitter/receiver pair in the second half of the present invention will be described. explain.

Ordinary optical systems are susceptible to interference on the optical axis, which is especially fatal if the reflector is contaminated.

There are two types of staining on the reflector: the entire surface and the partial stain, but in the latter case, the influence is determined by comparing the diameter of the light beam and the size of the stain.

Therefore, for example, the distance t between the emitter and receiver pair is determined by the effective h of the recurrent reflector.
′, the total number of emitter/receiver pairs will naturally increase in order to eliminate position detection errors due to contamination and deterioration on the surface of the recurrent reflector, but this will require that at least two emitter/receiver pairs be used for main detection. There are always two
Since the retroreflector operates in multiple directions, detection errors due to partial contamination of the retroreflector are prevented, and position detection signals are obtained in a dual system at the input section.

Therefore, high reliability regarding position detection has been achieved.

Although the above example shows the case where the reflector is placed perpendicular to the ground, the gist of the present invention is not limited to this, and the reflector may be placed horizontally or in some other angular relationship. Of course, it can be applied even in cases where

As mentioned above, a moving object such as a magnetic levitation vehicle that levitates on a track is equipped with a light projector/receiver (a plurality of coaxial light projector/receiver pairs arranged at regular intervals). According to the position detection device according to the present invention, which is provided with reflecting plates facing each other on the orbit that have the minimum necessary effective height or effective width and have retroactivity, regardless of the moving posture of the moving object, First, at least one light emitter/receiver pair is always within the operating range to constitute a reliable optical system, and at the same time, the size of the reflector can be kept to the minimum necessary, so economical efficiency can be expected.

Further, the number of the light emitter/receiver pairs and the spacing between the light emitter/receiver pairs are determined so that at least two of the plurality of light emitter/receiver pairs are always within the operating range, and Since the system detects the presence of a reflector, the reliability of operation can be greatly improved despite dirt on the reflector.

This invention will make an extremely large contribution in this field, as it will economically provide safety and smoothness for the high-speed operation of vehicles such as magnetic levitation vehicle systems, which will continue to develop in the future.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view of the track structure and the vehicle in the direction perpendicular to the track in the magnetically levitated vehicle system; FIGS.
The figure is a dimensional explanatory diagram of the light emitter/receiver pair, the light emitter/receiver device, and the reflector of an embodiment of this invention, and FIG. 4 shows another embodiment of this invention using a retroreflector and a coaxial light emitter/receiver pair. FIG. Explanation of symbols 1...Travelling vehicle body, 2...Track structure, 3.3'...Reflector, 4,4'...
...Light emitting and receiving device, 5... Retroreflector, 6
...Coaxial type emitter/receiver pair, 7... Light path.

Claims (1)

[Claims] 1. A pair of light emitters and receivers is provided on a moving body traveling on a track, and a retroreflector is provided at a predetermined ground detection position along the track, and the light emitted from the light emitter of the pair of light emitters and receivers is provided. A light emitter/receiver pair and a retroreflector plate are disposed facing each other so that the light is reflected by the retroreflector plate and reaches the light receiver of the light emitter/receiver pair again, and the position of the movable body is detected based on the presence or absence of the reflected light. In the position detection device, a plurality of pairs of light emitters and receivers on a moving body are arranged vertically at a predetermined distance t from each other, and the number n of the pairs of light emitters and receivers is equal to the effective height h of the retroreflector. /. When the above-mentioned equivalent maximum height change value H when the moving object is running, the height change value when the minimum positive integer satisfying the condition H((n-1), l+h') is supported and arranged, At least two or more pairs of the plurality of pairs, n, are arranged to effectively face the retroreflector, and at least one of the two or more pairs of light emitting and receiving light effectively facing each other is effective. A main detection emitter/receiver pair constituting an optical system for position detection, and at least one
The light emitter and receiver become a pair of auxiliary detection light emitters and receivers that constitute an optical system to prevent position detection errors due to partial deterioration of the reflective performance of the retroreflector. Mobile object position detection device 9 characterized by