JPS5924603B2 - Position detection device for linear motor vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a position detection device for a linear motor vehicle that detects the position of the vehicle relative to a propulsion coil on a track in a magnetic levitation railway.

In magnetic levitation railways, the position of the vehicle in relation to the coils (propulsion coils) arranged on the track soil for propulsion of the vehicle is detected, and this detection signal is used to control the frequency of the current in the propulsion coil. There is a method of controlling the driving of a traveling vehicle by doing this, and this method is called a separate excitation control method.

In this separately excited control system, the above-mentioned position detection signal used for controlling the propulsion current has the highest priority, and there are strict requirements regarding errors and detection accuracy. In contrast, attempts have been made to use an optical reflection type as a method with good detection accuracy. Figure 1a explains the outline of the optical propulsion coil position detection method that has been attempted in the past in magnetic levitation railways, and Figure 1b explains the position detection signal obtained from Figure 1a. The first
In Figure a, three optical detectors 2-A, 2-B, 2-C are installed along the traveling direction indicated by arrow R for the on-vehicle propulsion coil 1 with a total length of 1 installed on the vehicle. A pair of position detectors 2 are provided, and the distance between the detectors 2-A, 2-B, and 2-C is 1/3, respectively, and each unit coil Ul, which constitutes the ground propulsion coil 3, is l、Wl、・・・・・・
・The interval is set equal to 1/3.

Now, on the ground, optically facing the position detector 2,
and maintain a certain relationship with the propulsion coil on the ground and have a length of 1/2.
Reflecting plates 4 are arranged with an interval of 1/2.

As the vehicle moves in the direction indicated by arrow R, each of the detectors 2-A, 2-B and 2-C reads the reflector 4 and outputs a detection signal. FIG. 1b is a time chart of the detection signals, in which signals A, b and c correspond to detectors 2-A, 2-B and 2-C, respectively. These signals A, b and c are input to a propulsion current control device located on the ground using a suitable signal transmission system. As mentioned above, in the conventional ground propulsion coil detection method, in order to obtain the detection signals A, b, and c shown in FIG. In other words, the reflector plate 4
requires an extension of exactly 1/2 of the orbit length, and for short-distance experimental or trial orbits, this is a matter of course; for long-distance practical orbits, the total number of reflectors 4, The total weight will be enormous. Also, the length of the propulsion coil 1 on the vehicle is 1
For example, a 4.2M type has been tried, but based on the above-mentioned argument, the length of the reflector plate 4 needs to be 2.1M, which has the following disadvantages in manufacturing and handling.

Since magnetically levitated vehicles are subject to movement postures such as rolling and pitching while traveling, reflectors with so-called retroreflective properties are considered suitable for use in position detection devices. Such a retroreflector is considerably more expensive than a mere reflector made of metal, and the 2.1M long retroreflector requires special treatment in manufacturing.

Furthermore, long objects have many drawbacks, such as the need to take measures to withstand the range of severe temperature changes in orbit, or to prevent the decline in reflective performance due to contamination, which is a fatal drawback of optical systems. This is why it is desirable to have a position sensing device that eliminates the disadvantages associated with long reflectors as described above, improves economic efficiency by using short reflectors, and can output reliable propulsion coil position signals. It is. This invention aims to improve economic efficiency by shortening the length of the reflector in the optical reflection type propulsion coil position detection device that has been tried in the past for magnetic levitation railways, as well as to provide highly reliable detection signals. An object of the present invention is to provide a linear motor vehicle position detection device capable of outputting output. In this invention, a reflector having a length necessary and sufficient to detect the change point is placed at the end of the reflector in the conventional method, that is, at the position of the change point of the presence or absence of reflected light. The detection signals obtained by the detection are synthesized to obtain the propulsion coil position detection signal {shown in Figure 1b}, which achieves the original purpose of reducing the reflector size. .

However, in this case, the reliability of the error rate of the obtained detection signal varies depending on the method of installing the reflector and the arrangement of the detectors, so it is extremely important to use an appropriate method with high reliability. It is. Therefore, we will consider the reliability of the detection signal. First, in the conventional method described above, as shown in FIG. Figure 1 b} A, b, and c faithfully correspond to the presence or absence of the reflector 4. Even if a portion of the reflector 4 has a defect in its reflective performance due to dirt or damage, the entire reflector will be affected. Correct detection signals can be easily obtained as long as there are no defects.

Further, in this case, a defect existing in a certain reflecting plate 4 may cause an error only in the detection signal for that reflecting plate, but it does not have a similar effect on the detection signals from other reflecting plates. Now, in the method of detecting the above-mentioned change point in this invention, as shown in FIG.
In place of the conventional reflector plate 4, a new reflector plate 5 is placed at both ends of the reflector plate, that is, at the change point, and the same detectors 2-A, 2 as the conventional reflector plate are installed.
Let us consider a configuration in which a detection signal is obtained using -B and 2-C. In this case, each detector 2-A, 2-B, 2-C
It is clear that pulse signal trains D, e, and f are obtained as detection signals, and are processed by an appropriate signal processing circuit to obtain detection signals A, b, and c. However, if there is a defect in the reflection plate 5 shown by A in the figure and the pulse signal A7 is deleted, the detection signals obtained by combining them will be as follows:
In this case, not only will the detection signal for the reflector A be erroneous, but this error will become a so-called history, causing a serious error in that the phases of all subsequent detection signals will be reversed. In this way, the fundamental reason why a hysteresis phenomenon occurs in which an error in one location has ripple effects is that in the configuration described above, each of the detectors 2-A, 2-B, and 2-C simply has a reflector. It only captures the change point of
Since it does not distinguish whether it is a change to ``3 present'' or vice versa, from ``presence'' to ``absence'', once a detection error occurs, the change point will be changed from then on. This is because the "phase" (from "nothing" to "presence 1" or from "1 presence 0" to "1 nothing 2") is reversed.

In order to eliminate such serious drawbacks, the present invention employs a method for detecting the above-mentioned "phase" by making improvements to the installation of the reflector and the arrangement of the detector.

FIG. 3 shows the arrangement of the reflector and detector in the present invention, where the reflector 5 is placed only at one end of the conventional reflector 4.

For this purpose, two sets of position detectors 2 and 2' are provided. The position detector 2 is an optical detector 2-D, 2-E, 2-F.
1/3, exactly the same as the conventional case shown in Figure 1.
are arranged at intervals of Also, the position detector 2' is the detector 2-
D', 2-E', and 2-F', also spaced apart by 1/3, and placed behind or ahead of the position detector 2 by a distance of 1/2. Now, in the above configuration, each detection signal by the position detector 2 means a change from "absence" to "presence" (or vice versa) in the conventional reflector, and the position detector 2'
Each detection signal is taken as meaning a change from ``55'' to ``3'' and ``5'' (or vice versa), and is converted into a required detection signal by an appropriate signal processing circuit.

This completely eliminates the spread of errors due to the history described above. To explain this using FIG. 3, the detector 2-D
Pulse signals g and g' are obtained by 2-D' and 2-D', and a detection signal a shown in FIG. 1a is obtained by circuit processing. It is clear that the detection signals B and c can also be obtained in the same manner. Here, when the reflection performance of the reflection plate 5 shown in the middle part of FIG. 3 deteriorates and this is not detected, the pulse signal port 5 is deleted and the detection signal port 7 is deleted.

However, an error in this case has no effect on subsequent detection signals following mouth 2. For example, a flip-flop is used as a circuit for processing the above-mentioned signals as shown in FIG.
h' and i' are used as reset signals.
Furthermore, even when the vehicle is traveling in the opposite direction to the direction indicated by the arrow R in FIG. 3, the present invention can be applied as is by simply inverting the phases of the detection signals A, b, and c.

FIG. 4 explains the reflector 5 used in the position detection device for a linear motor vehicle according to the present invention, and the height dimension H is assumed to be the same effective height as the reflector used conventionally, and the system is When it changes, you can take it as you like.

The width dimension L in the traveling direction R of the vehicle is determined by the detector 2-D,
It is appropriate that the diameter of the spot coincides with the spot diameter w of the projected light beam. As the reflective material of the reflector plate 5, regardless of the moving posture of the vehicle, the reflected light can be transferred to the detectors 2-D, .
In order to accurately reach ..., we will use a retroreflector as in the past, and the width L can be significantly shortened (several tenths) compared to the conventional one, which will reduce the manufacturing difficulties. , the effects of temperature changes, etc. are greatly improved, and reflective materials such as hard plastic materials with extremely good retroreflection performance can be easily used, so improvements in detection performance can be expected. FIG. 5a is a right-angle cross-sectional view of the linear motor vehicle and the track, and FIG. 5b is a side view thereof, which explains the mounting positions of the reflector 5 and the detectors 2-D, . . . . be. The reflectors 5 are attached at a distance of 1 to an appropriate inner surface or bottom surface (running road surface) of the linear motor track. However, it is not necessarily preferable to place the reflector 5 on the bottom surface, as this may cause a reduction in reflection performance due to dust from the ground. Detectors 2-D, . . . are arranged at appropriate locations on the vehicle body 8, facing the reflecting plate 5, at the intervals described above. In this case, if it is not possible to arrange the detectors at the intervals as described above due to structural reasons of the traveling vehicle body 8, each detector can be independently moved forward or backward by a distance of 1 or an integral multiple thereof. . This is because the position detection signal does not contain information about the absolute position of the individual propulsion coils. FIG. 6 shows a schematic block diagram of a signal processing circuit in an embodiment of the position detection device for a linear motor vehicle according to the present invention, in which each detector 2-D, . . . A pulse signal is output, and a detection signal pulse is output only when the pulse signal is equal to or higher than a certain threshold level by the comparison circuits 9-D, .

By appropriately setting the threshold level, malfunctions caused by external light can be prevented. In the flip-flop 10-D, the detection signal pulse of the comparator circuit 9-D is inputted to the set terminal S, and the detection signal pulse of the comparator circuit 9-Dl is inputted to the reset terminal R. Similarly, flip-flops 10-E and 10-F provide detection signals B and c.

In the above, the output terminals Q and Q of the flip-flops 10-D, . It is something.

However, by switching the output terminals Q and Q for reciprocating travel of the vehicle, it is possible to obtain an output signal with the correct polarity for reciprocating or reciprocating. As explained above, in the position detection device for a linear motor vehicle according to the present invention, the length of the reflector in the track direction is several tenths of that of the conventional reflector-based method.
There are significant improvements in many respects, such as the ability to use reflective materials with good reflective performance, ease of manufacture and installation, and extremely easy cleaning and maintenance to maintain reflective performance.

In addition, the detectors are placed in an appropriate positional relationship based on theoretical considerations, and the same detection signals as conventional ones can be obtained, even if an erroneous signal is generated due to a defect in the reflector.
This method does not affect subsequent detection signals, and together with the improved performance of the reflector, we can expect a detection signal with higher reliability than ever before. Although the number of detectors is increased compared to the conventional method, the cost of the reflector can be significantly reduced, making it possible to construct a system that is far more economical overall, making it an extremely effective invention.

[Brief explanation of the drawing]

Figure 1a shows an on-board propulsion coil in a vehicle position detection device conventionally used in magnetic levitation railway experiments.
Figure 1b is a position detection signal waveform diagram obtained by the detector shown in Figure 1a, and Figure 2 is a diagram showing the positional relationship between the ground propulsion coil, position detector, and reflector. point)
Explanation time charts for errors occurring in detection signals in the detection method, Figures 3 to 6 all show embodiments of the present invention, and Figure 3 shows detection in a position detection device for a linear motor vehicle. Layout of the vessel and reflector,
Fig. 4 is a configuration diagram of a reflector, Fig. 5 is an installation layout diagram of a reflector and a detector of a position detection device for a linear motor vehicle, and Fig. 6 is a signal processing circuit diagram of a position detection device for a linear motor vehicle. It is a block diagram. 1... Vehicle propulsion coil, 2, 2/-... Position detector, 2-A, 2-B, 2-C, 2-D, 2-D'
, 2-E, 2-E', 2-F, 2-Ft... optical detector, 3... ground propulsion coil group, 4, 5...
...Reflector, 6...Detector light beam spot, 7...Trajectory, 8...Traveling vehicle body, 9...Comparator , 10...Flip-flop.

Claims (1)

[Claims] 1 As a propulsion method for linear motor vehicles, three
In a separately excited propulsion current control system in which a set of three ground propulsion coils for each phase propulsion current is arranged in succession, and an on-vehicle propulsion coil is installed on the traveling vehicle opposite to the ground propulsion coil, On the track, reflectors are arranged at equal intervals to the pitch of the above three ground propulsion coils, detected by an optical method, and have the minimum necessary width.
Two sets of position detectors each consisting of two optical detectors each having a distance of 1/3 of the total length of the above-mentioned set of ground propulsion coils; Among the detection signal pulses of the position detector arranged at a distance of
A signal processing circuit is provided for inputting a group of two phase-corresponding flip-flops to each set of three flip-flops and a reset terminal, and a ground propulsion coil and a ground propulsion coil for controlling the three-phase propulsion current are provided. A position detection device for a linear motor vehicle, characterized in that it is capable of outputting a detection signal indicating the mutual positional relationship of the vehicles.