JP2765017B2 - Stop control device of magnetic levitation carrier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a magnetic levitation carrier for stopping a magnetic levitation carrier traveling in a non-contact state on a guide rail formed of a ferromagnetic material at a predetermined position. It relates to improvement of a stop control device.

<Conventional technology> The non-contact transport system is a non-contact transport method that guides a transport vehicle on a guide rail when it is desired to quickly and quietly transport a conveyed object such as precision parts between multiple points in a factory or office. This is a system in which the vehicle travels while supporting it in a state. There are various methods for supporting the carrier in a non-contact state,
As one of the methods, a transfer method using a magnetic levitation transfer vehicle is currently considered promising because it is excellent in terms of noise, hygiene and the like.

Since the above-mentioned magnetic levitation transport vehicle is required to be small and lightweight, only a conductor (secondary conductor) for passing an induced current on the vehicle is provided, and a heavy one having a propulsion coil on the ground is provided. A drive control device for arranging a drive system on the next side and supplying power to the coil to start, run, and stop the magnetic levitation transport vehicle is usually provided.

As one of the traveling control devices, for example, a suspension control device of a magnetic levitation carrier for stopping the magnetic levitation carrier at a predetermined position has already been devised by the present inventor (Japanese Patent Application No. Sho 62-62). 281807, 62-281811).

The above device attaches a linear scale in which a number of bars are arranged in parallel at predetermined intervals along the traveling direction of the vehicle of the magnetic levitation carrier, and uses a non-contact type position sensor provided on the stop station side to set the linear scale. The scale is read, the position of the magnetic levitation carrier is detected almost continuously, the speed of the magnetic levitation carrier is calculated from the time change of the position, and the speed data at the read position is compared with the reference speed data. By supplying a drive control output signal to a drive system for driving the ground-side primary linear motor based on the amount of the deviation, the magnetic levitation carrier is accurately stopped at the stop position.

With this device, the position and speed of the magnetic levitation carrier traveling on the track are almost continuously obtained, and feedback control is performed with the reference position and speed as target values, thereby providing a drive control output signal to the drive system. , The occurrence of overshoot (being beyond the stop position) and the like can be suppressed, and the magnetic levitation carrier can be accurately stopped at a predetermined stop position.

<Problems to be Solved by the Invention> In the above-described stop control device, in order to improve the stop accuracy, it is only necessary to reduce the interval between the bars, but then, it is necessary to read the bar which must be read before stopping at a fixed point. The number is enormous, which increases the number of digits of the counter circuit provided in the stop control device. Therefore, a calculation based on the number of bits of the storage device storing the count value and the count value,
A large number of bits is required for the CPU that performs the stop control.

As a result, there arises a problem that the configuration of the entire stop control circuit is complicated and expensive.

Therefore, an object of the present invention is to provide a stop control device that has a high stop accuracy and requires only a small number of bits in a stop control circuit.

<Means for Solving the Problems> The stop control device of the present invention for achieving the above object has scale counting means for counting the scales of a scale attached to a magnetic levitation carrier, and the counting is performed by this. If the number of bits of the digital signal representing the number is M, relatively high-order N bits (0 ≦ N ≦
M) or switching means for selecting and taking out relatively low-order N bits, the stop control means operating the switching means based on whether the magnetic levitation carrier has passed a predetermined point, and The fixed-point stop control is performed based on the N-bit digital signal.

<Operation> In the initial stage of entering the stop position, the speed of the magnetic levitation carrier is high, and the magnetic levitation carrier is away from the stop position, and the reading accuracy of the scale is smaller than that near the stop position. It may be slightly coarse. Conversely, at a position near the stop position, the speed of the magnetically levitated vehicle is low, and fine reading of the scale is required.

Therefore, when the reading accuracy of the scale may be coarse, the upper N bits of the digital signal corresponding to the count number of the scale are read, and the fraction is omitted. When it is necessary to make the reading accuracy of the scale fine, only the lower N bits of the digital signal are read.

As described above, the number of processing bits can be reduced without lowering the accuracy of the stop device.

<Example> Next, an example of the present invention will be described below with reference to the drawings.

FIG. 2 is a sectional view showing a magnetic levitation carrier traveling along a track, FIG. 3 is a sectional view taken along the line III-III of FIG. 2, and FIG. Only the guide rail (21) is shown). The traveling direction of the magnetic levitation transport vehicle is a direction perpendicular to the paper surface in FIG. 2, and the direction of the arrow A in FIGS. 3 and 4.

The magnetic levitation transport vehicle (1) has a flat body (2) also serving as a carrier, and a total of four frames (3) are provided on the upper surface of the body (2), two on the front side and two on the rear side in the traveling direction. )
Is placed facing up. A floating magnet (4) composed of a composite of a permanent magnet and an electromagnet is fixed to the upper part of the frame (3). A landing roller (7) and a guide roller (8) are provided on the side surface of the vehicle body (2) so as to protrude from the frame (3). The landing roller (7) regulates the vertical movement of the magnetic levitation transport vehicle (1) during landing, and the guide roller (8) regulates the horizontal movement of the magnetic levitation transport vehicle (1). Things. Note that (9) is a gap sensor that measures the gap between the levitation magnet (4) and the guide rail (21) by using, for example, an electromagnetic induction effect, and (10) is provided at the bottom of the vehicle body (2). It is a hook for hanging luggage.

As shown in FIG. 2, the track (20) has a long frame body (23) with an open bottom, and a cross section made of two ferromagnetic materials suspended from the ceiling of the long frame body (23). It is composed of a guide rail (21) having an "D" shape, a guide groove (24) formed of an L-shaped material for supporting a landing roller formed inward from the side of the long frame (23), and the like. You.

At the center of the vehicle body (2), a thin reaction plate (6) is set upright in parallel with the traveling direction. Correspondingly, a magnetic levitation carrier ( A primary drive system (22) of a LIM (linear induction motor) for starting, accelerating, decelerating, and stopping 1) is provided.

On the side surface of the vehicle body (2), a linear scale (38) for displaying the position of the magnetic levitation transport vehicle (1) almost continuously in order to accurately stop the station at a predetermined position. Is provided.

As shown in FIG. 5, the linear scale (38) has fine scales (for example, about 0.1 mm increments) on the left and right of the stop position (a) as a center. Are slightly offset from each other). A reading switching point (b) is provided at a position 1 cm away from the stop position (a). The detection of the reading switching point (b) may be performed based on the scale count number by the position data detecting circuit (40) (FIG. 1) (in this case, the position of the reading switching point (b) cannot be visually identified. However, the 4900th scale counted from the end point (c) of the linear scale (38) becomes the reading switching point (b)), and a mark which can be detected by the scale detection sensor (37) may be attached. .

On the ground side, a position data detection circuit (4
0), a speed data calculation circuit (49), a stop control circuit, and the like. The stop control circuit is connected to an operation management host computer (not shown) through a bus.

As shown in FIG. 1, the position data detection circuit (40) forms an output signal from the optical scale detector (37) for reading the scale in a non-contact manner,
波形 A waveform shaping circuit (42) that outputs different pulse signals (42a) (42b), and a pulse signal (42a) (42b) is input and the up-count pulse (43a, magnetic levitation carrier (1) is A pulse generation circuit (43) that outputs a down-count pulse (43b, when the magnetic levitation vehicle (1) is retreating), or a pulse based on the pulse (43a) (43b). A counter circuit (44) for outputting a 12-bit digital signal indicating a count number, the upper 8 bits or lower 8 bits of the digital signal;
A switching circuit (45) for selecting and taking out one of the bits by switching, and an 8-bit latch circuit (46) for latching an output signal of the switching circuit (45).

The output of the latch circuit (46) is input as a position data signal to an 8-bit microcomputer (50), and the microcomputer (50) receives the speed signal of the magnetic levitation carrier (1) from the 8-bit signal. A speed data calculation circuit (49) comprising an F / V converter (49-1) to obtain the output and an A / D circuit (49-2) for A / D converting the F / V conversion output; and a sampling pulse generator (53). And are connected. The microcomputer (50) outputs a stop control output signal based on the position data and speed data, and outputs a D / A converter (5
1) Inverter (36) through buffer amplifier (52)
To send out. The inverter (36) is a buffer amplifier (5
The output of 2) is converted into a power signal for driving the primary drive system (22) of the LIM.

The counter circuit (44) corresponds to the scale counting means, the switching circuit (45) corresponds to the switching means, the speed data calculation circuit (49) corresponds to the speed calculation means, and the microcomputer (50). Corresponds to stop control means, and the inverter (36) corresponds to a drive system.

The microcomputer (50) obtains the position data and the speed data of the magnetic levitation transport vehicle (1) at each sampling time, calculates whether the speed at the position is different from the reference speed, and calculates the deviation. Based on quantity
Controls the output sent to the inverter (36).

The stop control means will be described in detail with reference to a flowchart (FIG. 6). When a stop command of the magnetic levitation carrier is received from the host computer in the step, the step waits until the magnetic levitation carrier (1) enters the station in the step. . This approach can be known from the fact that the scale detector (37) has detected the end point (c) (see FIG. 5) of the linear scale (38). In this case the microcomputer (50) sends a predetermined operation signal to the switching circuit (45), selecting only the upper 8 bits (2 ⁴ to 2 ¹¹⁾ of which is the output 12-bit digital signal of the counter circuit (44) (Step). In other words, the lower 4 bits (2 ⁰ ~
2 ³ ) will be discarded, which means reading 16 scales at once. Therefore, if the number of scales is 5000, the total count is reduced to about 300.

If the switching circuit (45) is not provided, the total count is 5000, so that the latch circuit (46) and the microcomputer (50) need to have 12 bits or more.

Thereafter, the speed data calculation circuit (49) operates to start calculating the speed together with the position (step). Each time the microcomputer (50) receives a pulse from the sampling pulse generator (53) in the step, the microcomputer (50) fetches position data and velocity data (step), and determines coordinates on the phase space composed of the position and velocity (step). Steps). Then, it is determined whether or not the position coordinates have reached the reading switching point (b) in the step (step). If the coordinates have not reached the reading switching point (b),
In a step, a difference between the speed and the reference speed is calculated. The reference speed is defined for each position of the magnetic levitation carrier (1), and can be plotted as a reference line on a phase space. And in the step,
The driving force is calculated such that the deviation from the reference speed becomes smaller as the magnetic levitation carrier (1) travels, and reaches the origin quickly without vibrating in the phase space. Then, in a step, an output signal corresponding to the driving force is transmitted to the inverter (36), and the process returns to the step. The procedure of the above-mentioned steps is repeated until the position coordinates of the magnetically levitated vehicle (1) reach the reading switching point (b) in the steps.

If the reading switching point (b) has been reached, the process proceeds to step and it is determined whether or not it is exactly at the origin on the phase space.
If YES, it is determined that the magnetic levitation transport vehicle (1) has stopped at the predetermined position, and no output is sent to the inverter (36) (step), and the process returns to the step. If not, the microcomputer (50) sends a predetermined operation signal to the switching circuit (45), and outputs the lower 8 bits (2 ⁰ ) of the 12-bit digital signal output from the counter circuit (44). ~ 2 ⁷⁾ to select only (step). Thereafter, the procedure following the step is repeated based on the lower 8 bits. As a result, 100 scales from the reading switching point (b) to the stop position (a) can be read one by one, so that it is possible to stop at the stop position with good accuracy.

According to the above procedure, the magnetic levitation transport vehicle (1) can be smoothly and accurately stopped at the stop position.

In the stop control procedure, the determination in the step is made based on the position coordinates in the phase space. However, when a mark is provided on the scale, the determination may be made based on whether or not this mark has been detected. Further, it is of course possible to change the numerical values such as the number of scales and the number of bits in the above embodiment. Various other design changes can be made without departing from the scope of the present invention.

<Effects of the Invention> As described above, according to the magnetic levitation carrier stop control device of the present invention, the stop is performed by selectively using upper or lower bits of the digital signal corresponding to the count number of the scale. Since the control is performed, the number of processing bits can be reduced without lowering the accuracy of the stop position.

Therefore, the number of bits of the speed calculation means for calculating the speed based on the count value and the number of bits of the stop control means for performing the calculation and the stop control based on the count value are also reduced, so that the entire apparatus can be simplified, downsized, and reduced in cost. .

[Brief description of the drawings]

FIG. 1 is a block diagram showing a position data detection circuit and the like. FIG. 2 is a sectional view showing a magnetic levitation carrier traveling on a track perpendicular to the plane of the drawing. FIG. 3 is a sectional view taken along the line III-III of FIG. FIG. 4 is a perspective view of a magnetic levitation carrier, FIG. 5 is an enlarged view of a linear scale, and FIG. 6 is a flowchart of a stop control procedure. (1)… magnetic levitation carrier, (21)… guide rail, (36)… inverter, (37)… scale detector, (38)… linear scale, (44)… counter circuit, (45) Switching circuit (48) Speed data calculation circuit (50) Microcomputer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-270664 (JP, A) JP-A-63-198505 (JP, A) JP-A-63-64589 (JP, A) JP-A 62-1985 263410 (JP, A) JP-A-55-57910 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B60L 13/02 G05D 3/12

Claims (1)

(57) [Claims] 1. A scale mounted on a magnetic levitation carrier that travels in a non-contact state on a guide rail formed of a ferromagnetic material, a scale detector provided on the ground side for detecting a scale, and a scale. Scale counting means for counting the scale of the scale, speed calculating means for calculating the speed of the magnetic levitation carrier based on the scale count number, and reading and reading the position and the calculated speed of the magnetic levitation carrier corresponding to the scale count number. Is compared with the reference speed at the position, and based on the deviation, a drive control output signal is supplied to a drive system that drives the ground-side primary linear motor, thereby performing fixed-point stop control of the magnetic levitation carrier. And a stop control device for the magnetically levitated vehicle, comprising:
, And N relatively high-order bits of M bits (0 ≦ N
≦ M) or relatively low-order N bits, and a stop control unit operates the switch unit based on whether the magnetic levitation carrier has passed a predetermined point. And performing the fixed point stop control using the selected N-bit digital signal.