JPS62287310A - Multi-head type position detecting device and position controller - Google Patents

Abstract

PURPOSE:To execute a position control of each truck so that a mutual interference or an abnormal approach does not occur, by providing a position detecting pattern along a guide, so that each position detecting head which has been attached to each truck can detect an absolute position in response to this pattern. CONSTITUTION:In accordance with a rotation of each motor M1-M10, each track 3-1-3-10 runs independently and freely, respectively, along guide rains 1, 2. Each truck 3-1-3-10 is loaded with position detecting heads 6-1-6-10. Also, sensor rods 20-22 are provided along a length range of the guide rails 1, 2. The sensor rods 20-22 are provided with a prescribed position pattern, and each position detecting head 6-1-6-10 detects a head in the overall length of the guide rails, 1, 2, namely, an absolute position of each truck 3-1-3-10, in response to said pattern.

Description

[Detailed Description of the Invention] Detailed Description of the Invention [Field of Industrial Application] This invention enables a plurality of carts that move independently on a common guide to be controlled without mutual interference or abnormal approach. The present invention relates to a multi-head type position detection device that detects the absolute position of each truck, and further relates to a position control device using this multi-head type position detection device.

[Conventional technology]

In machine tools or industrial machinery, there are cases where it is necessary to independently move a plurality of tools on a common guide and control their positions. For example, in a paper cutting machine, in order to quickly respond to various cutting sizes, multiple blades are moved independently on a common guide, and any of them is positioned to perform selective cutting operations. The idea is to make it happen. In this case, in order to position the tools without mutual interference or abnormal approach, it is necessary to accurately detect the position of each tool.

Conventionally, there is no suitable position detection device for this purpose.

[Problem that the invention seeks to solve]

The method of generating incremental pulses in response to displacement and counting them to obtain position data has been well known, but this method was developed to move multiple tools independently on a common guide as described above. could not be applied. This is because, in the case of such an incremental method, it is essential to perform pulse counting from the home position, but only one tool can be returned to the home position on the common guide, and other tools cannot be returned to the home position. This is because return to origin cannot be performed. It is also possible to attach a rotary absolute position detector (rotary absolute encoder) to the transport motor of each tool and obtain the position data of each tool from its absolute rotational position. Since these are completely independent of each other, a problem arises in that it is extremely troublesome to align their origins. Also,
There is also the hassle of having to align the origin each time the detector is replaced due to a malfunction or the like.

This invention has been made in view of the above points, and is intended to easily and reliably detect the absolute position of each tool when moving multiple tools independently on a common kite and controlling their positions. It is an object of the present invention to provide a multi-head type position detection device that can perform the following functions, and also to provide a position control device using the detection device.

[Means for solving problems]

A multi-head position detection device according to the present invention includes a plurality of carriages that are movable independently along a common guide, a position detection pattern provided along the guide, and a position detection pattern that is attached to each carriage, and The present invention is characterized by comprising a position detection head for detecting the absolute position of each carriage on the guide in response to the pattern.

Furthermore, the position control device of the present invention is equipped with the multi-head type position detection device as described above, and the position control device is equipped with the multi-head type position detection device as described above. Based on the absolute position data for each cart and the absolute position data of the carts adjacent to each cart, each cart is positioned at its corresponding target position while controlling so that each cart does not approach abnormally close to the adjacent cart. It is characterized by being equipped with positioning means.

[Effect]

In the multi-head position detection device of the present invention, a position detection pattern is provided along the guide, and each position detection head attached to each carriage detects the absolute position of each carriage in response to this pattern. do. Since the position detection pattern is common to each position detection head, there is no need to perform origin adjustment for each head, which saves time and effort for origin adjustment.

Further, according to the position control device of the present invention, not only the target position data and the absolute position data of the cart to be positioned, but also the absolute position data of the neighboring cart are taken into consideration, Positioning is performed while controlling to avoid abnormally approaching the trolley. It is immediately known by comparing the absolute position data of the two that an adjacent cart has approached a predetermined abnormal approach distance, so in order to prevent such an abnormal approach from occurring, it is determined not only the relationship with the target position but also the distance between adjacent carts. Position control is also performed in relation to the position of the truck.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 1, a plurality (for example, 10) of carts 3-1 to 3-10 are mounted on two guide rails 1 and 2 installed over a predetermined range. A rack 4 is fixed along the guide rail 1, and each trolley 3-1~
Pinions 5-1 to 5-10 attached to the rotating shafts of motors M1 to MjQ fixed to 3-10 are engaged with the rack 4.

Depending on the rotation of the individual motors M1-MlQ, each trolley 3-
1 to 3-10 are adapted to independently run on their own along guide rails 1 and 2, respectively. Controlled objects such as tools are attached to predetermined locations T (indicated by diagonal lines) of each of the trolleys 6-1 to 3-10. Position detection heads 6-1 to 6-10 are mounted on each of the carts 3-1 to 3-10. Additionally, sensor rods 20 and 21 are provided along the length range of the guide rail 1°2.
22 is provided. The sensor rods 20 to 22 are provided with a predetermined position detection pattern, and the throats 6-1 to 6-10 respond to this pattern to detect the head clogging in the entire length range of the guide rails 1 and 2. The absolute position of each truck 3-1 to 3-10 is detected.

Position detection heads 6-1 to 6-10 and sensor rod 20
As a linear position detection method using .about.22, for example, a method as shown in Japanese Patent Application Laid-open No. 79114/1983 can be used. An example of this case is shown in FIG.

In FIG. 2, one position detection head 6-1 has three sensors s1 corresponding to three sensor rods 20 to 22.
．． s2. Consists of s3. First, the sensor S1 will be explained. This sensor S1 consists of primary coils 7 to 10 and secondary coils 11 to 10 housed in a predetermined arrangement in a casing 15.
14.

A sensor lower F20 is slidably inserted into this coil. The sensor lot 20 includes a repeating pattern of magnetic material M and non-magnetic material N repeatedly provided with a length of P + /2 as a position detection pattern. In this embodiment, the coils are arranged to operate in four phases. For convenience, these phases are distinguished using symbols A, B, C, and D. The link tances generated in each phase A-D are shifted by 90 degrees depending on the position of the magnetic body M. For example, if the human face is a cosine phase, the B phase is a sine phase, the C phase is a minus cosine phase, The D phase is a minus sign phase.

In FIG. 2, the primary coil 7 is individually set for each phase A-D.
．． 8.9.10 and secondary coil 11,12゜13.14
is provided. Secondary coils 11 to 1 of each phase A = D
4 are wound around the outside of the corresponding primary coils 7 to 10, respectively. is the length of each coil. In the example shown in FIG. 2, the human-phase coil 7.11 and the C-phase coils 9, 13 are installed adjacent to each other, and the B-phase coils 8, 12 and the D-phase coil 10.14 are also adjacent to each other. It is provided. Also, the A phase (n is any natural number).

Further, the arrangement of the coils of each phase A to D in the sensor 1 is not limited to that shown in FIG. 1. That is, the reluctance of the magnetic circuit in each phase A-D changes according to the linear displacement of the magnetic body M, and the phase of the reluctance change shifts by 90 degrees in each phase (therefore, the phase difference between A and C phases is 90 degrees).
80 degrees, and even the B phase and D phase are 180 degrees apart), so it is only necessary to bring about such a change in reluctance.

It is preferable that the sensor S1 uses a phase shift method (therefore, performs position detection. In that case, for example, one of the A phase and C phase
The secondary coils 7 and 9 are excited with opposite phases to each other by the sine signal sinωt, the outputs of the secondary coils 11 and 13 are added in the same phase, and the primary coils 8, 1
0 is excited in reverse phase with the cosine signal CO5ωt, and the secondary coil 12
．． 14 outputs are added in-phase. As a result, the combined output Y of the secondary coils 11 to 14 becomes a signal Y+=Ksin(ωt+φl). Here, K is a constant and the phase φ1 is proportional to the position of the sensor S1 with respect to the rod 20.

This phase φl makes one pitch length Pl of the repeating pattern of the magnetic material M in the a-nod 20 equal to 360 degrees, and indicates the absolute position within the range of Pl. Therefore, by measuring the electrical phase shift amount φ1 in the secondary output signal Y of the sensor S1, the absolute position within the range of Pl can be detected.

Sensor S2 has the same configuration as Sl, but one pitch length P2 of the repeating pattern of magnetic material M and non-magnetic material N in the corresponding sensor rod 21 is different from Pl. This sensor S2 is also operated using a phase shift method, and its secondary output signal Y2 is Y2 = K sin (ωt + φ2), and by measuring the phase φ2, the absolute position within the range of Pl can be detected. Can be done.

In this way, the sensor S1 generates periodic position detection data with the mechanical linear displacement pl as one cycle, and the sensor S2 generates periodic position detection data with the mechanical linear displacement P2 as one cycle.

Two sensors s1. The output of s2 is used to obtain magnified absolute position data by a method whose principle will be explained below.

First, each sensor s1. It is assumed that s2 generates a value R as an output signal for one cycle.

In other words, when the mechanical displacement amount is -p, the sensor S1 outputs an output signal for one period, that is, the maximum output R, and when the amount of mechanical displacement is Pl, the sensor S2 outputs an output signal for that one period, that is, the maximum output R. . When the amount of mechanical displacement from the origin becomes Pl or 22 or more, the sensor s1. With s2 alone,
The absolute position cannot be detected unless you know how many cycles these output signals are from the origin. However, as shown below, sensor s1. By using the output signals of s2 in combination, the absolute position can be determined.

Similarly, from the origin (at the origin, the outputs of sensors S1 and S2 are both 0), P! Thinking about when the group moves, the sensor S
The output of 1 is R, which is exactly one revolution. Therefore, with respect to the current position of the detection target, the sensor s1. Let Dl be the value of the output signal obtained from s2.

When expressed as D2, at absolute position P1,
, D2 is repeated once as follows.

D, =R From this, for one cycle of linear displacement P1 of sensor S1, both sensors s1. It is clear that the value of the output signal during s2 shifts sequentially according to the following variation (constant). Here, it is assumed that Dl2 = D1 D2.

...(2) Therefore, each sensor S1, S corresponding to the current position of the detection target
2 output difference "Dl2 = D + D2 J" is calculated and divided by the constant of the above equation (2) as shown below to find out how many cycles (CX ).

By the way, the difference between the outputs of each sensor s1 and s2, □, becomes maximum when the output of sensor S1 is the maximum output R and the output of sensor S2 is 0, and in this case, Dl2 beam, = R - 0 = R becomes.

Therefore, in the above equation (3), the maximum value CXMAX that the number of cycles Cx can take is sensor S1. It shows the maximum detectable range of Abunlute when S2 is used.

By the way, in this embodiment, the total length of the rods 20 to 22 (that is, the total length of the guide rails 1 and 2) is determined by the two sensors s1. This is twice the maximum absolute detectable range by s2. That is, E in FIG. 2 is the origin, F is the intermediate point, and the third sensor S3 and the corresponding sensor rod 22 are provided to detect the absolute position E.

The sensor S3 outputs an electrical output signal D3 at a different level when the mechanical linear displacement exceeds the range shown in equation (4) above.
is generated. In other words, when the output signal D3 is within 1, the signal "l" is output as the output signal D3.
occurs.

Therefore, the integer part of the period number CX in equation (3) above and the sensor S
This sensor S
(The value of signal D3 is used as a signal indicating a carry when the values of output signal D3 of 3 are combined as one cycle.) It is possible to specify the linear position of the detection target in absolute across two sensors. become.

In the example of FIG. 2, the sensor S3 consists of a pair of primary coil 42 and secondary coil 43, and the sensor rod 22 inserted into this coil has a non-magnetic material N from the origin E to the intermediate point F, and a non-magnetic material N in the middle. The area after point F is made of magnetic material M.

Sensor s1. The secondary side output signals Y1 and Y2 of s2 are
Each pitch length P1 is determined by applying it to the phase difference detection circuits 37-1 and 37-2 as shown in the figure.

It is possible to obtain a periodic digital output signal, D2, in which one period is the mechanical linear displacement corresponding to P2.

In FIG. 3, the oscillator 32 generates a reference sine signal sinω
The phase difference detection circuit 37-1 is a circuit for generating the cosine signal cosωt, and the phase difference detection circuit 37-2 is a circuit for measuring the phase shift φ1, and 37-2 is a circuit for measuring φ2. Clock pulses CP generated by a clock oscillator 33 are counted by a counter 30. The counter 30 is, for example, a modulo R, and from its count value output, a pulse Pc obtained by frequency-dividing the clock pulse CP is taken out and applied to the C input of a flip-flop 34 for frequency division by one. The pulse Pb output from the Q output of the F'J7 pfronop 34 is applied to the flip-flop 35, the pulse P output from the 100 output is applied to the flip-flop 36, and the outputs of these 35 and 36 are applied to the low-pass filters 46 and 47. A cosine signal cosωt and a sine signal sinωt are obtained via amplifiers 48 and 49, and sensors s1. It is input to s2. counter 30
The R counts in these reference signals cosωt,
This corresponds to a phase angle of 2π radians of sinωt. That is, one count value of the counter 30 indicates a phase angle of '1 g radian.

In circuit 37-1, output signal Y1 of sensor S1 is applied to comparator 26 via amplifier 25, and the signal Y1 is applied to comparator 26 via amplifier 25.
A square wave signal corresponding to the positive/negative polarity of the comparator 2
It is output from 6. In response to the rise of the output signal of the comparator 26, the rise detection circuit 28 outputs a pulse Ts, and the count value of the counter 30 is loaded into the register 31 in response to this pulse Ts. As a result, a digital value corresponding to the phase shift φ1 is taken into the register 31.

The other circuit 37-2 has the same configuration as the circuit 37-1, and inputs the secondary output signal Y2 of the sensor S2 to the comparator 39 via the amplifier 38, and controls the register 41 via the rising edge detection circuit 40. , a digital value D2 corresponding to the phase shift φ2 is taken into the register 41 from the counter 30. Note that only one phase difference detection circuit 37-1 is provided, and only the register 61.41 is connected to each sensor s1. The phase difference detection circuit may be provided corresponding to s2, and the phase difference detection circuit may be used in a time-division manner.

Both sensors S1. determined as above. The output signals of S2, D2 are supplied to an arithmetic unit (not shown), and the
3) Perform calculations according to the formula.

The sensor S3 is given either the sine signal sinω or the cosine signal cosωt generated from the oscillation unit 32 in FIG. 3, for example, and the primary coil 42 is excited by this signal (in FIG. 3, the cosine signal The signal cosωt is sent to the sensor S
3).

However, by applying an AC signal or a DC signal generated from an appropriate circuit other than the oscillating section 62 to the sensor S3, the primary coil 42
It is also possible to excite the . When the primary coil 42 is excited and the non-magnetic material N portion of the sensor rod 22 is inserted into the coil 42° 43, 2
An output signal Y3 having a relatively small level L1 is induced from the secondary coil 43 under relatively large reluctance. On the other hand, the magnetic material M portion of the rod 22 is connected to the coil 4.
2.43, an output signal Y3 having a relatively large level L2 is induced from the secondary coil 43 under relatively small reluctance. As a result, the secondary coil 43 outputs a signal Y3 of low level L1 while the part of the rod 22 from the origin to the intermediate point F passes through the space surrounded by the primary coil 42, and While the portion passes, the signal Y3 of high level L2 is output.

The output signal Y3 of this secondary coil 43 of the sensor S3 is given to an analog comparator 45 via a rectifier 44, as shown in FIG. For example, the analog comparator 45 has a reference voltage level vref set between levels L2 and Ll, and outputs a signal "0" as the output signal D3 when the level of the signal Y3 is high, and when the level of the signal Y3 is low as L2. At some point, the output signal D3 is the signal II II
Outputs +.

The output signal D3 of the sensor S3 obtained in this way is used as a signal indicating the carry of the absolute linear position data C(X) based on the outputs of the sensors S1 and S2 as described above, so that the entire area of the guide is Abnolute position detection over the entire range becomes possible.

The other position detection heads 6-2 to 6-10 are also 3
one sensor s1. s2. Consists of s3.

However, it is not necessary to separately provide a measurement circuit for each head as shown in FIG. It can also be shared.

The sensor rods 20 to 22 are commonly used for each head 6-1 to 6-10. Therefore, each head 6-1 to 6
Since the heads -10 each detect the absolute position relative to a common origin, there is no need to adjust the origin between the heads 6-1 to 6-10.

In the above embodiment, the pattern of the sensor rods 20 to 22 is a repeating pattern of magnetic material and non-magnetic material, but is not limited to this, and may be a repeating pattern of conductive material and non-conducting material, or a repeating pattern of conductive material and magnetic material. There may be. Further, the pattern of the conductor or magnetic material does not need to extend to the rod core, and may be attached to the rod surface. The shape of the pattern is not limited to a repeating pattern, but any pattern that allows absolute position detection may be used.

Further, the sensor method is not limited to a method that responds to a change in magnetoresistance, but other methods such as a method that responds to a capacitance change or a method that reads an optical pattern may be used. Furthermore, position detection patterns may be provided on the guide rails 1 and 2.

In the above embodiment, the number of sensor rods 20 to 22 is 3.
It is not limited to books, but may be two or four or more. If only the rods 20 and 21 are used, only the sensors Sl and S2 are needed, and the pattern of the absolute rod 22 is the second one.
Instead of using the pattern for creating a carry signal as shown in the figure, a repeating pattern like the pattern of the rods 20 and 21 may be used.

In that case, the one-pitch length P3 of the repeating pattern is Pl, P
2 will be slightly different from 2. In addition, the calculation formulas for obtaining expanded absolute position detection data are (1) to
It is not limited to Equation (3), but may be any other arithmetic expression (for example, simultaneous equations).

When moving a desired cart 3-x from its current position to a desired target position, the current position of the cart 3-x and the current positions of other carts are determined based on the output of each detection head 6-1 to 6-10. The relationship between the carts 3-X and 3-X is investigated, and the carts 3-X are moved to other positions as much as necessary to move the cart 3-X from the current position to the desired target position without any problems, and then the cart 3-X is moved to another position (or while being moved). All you have to do is move X. In this way, a plurality of carts 3-1 to 3-1 along the common guide rails 1 and 2
Abn lute position data detected by each of the detection heads 6-1 to 6-10 is used in order to perform desired positioning of the cart 3-x while controlling the robots 3-x to avoid mutual interference or abnormal approach.

FIG. 4 is a block diagram showing an embodiment of a position control device related to the position detection device of FIG. 1. Control units) C1 to C1 correspond to each position detection head 6-1 to 6-210.
0 is provided for each.

Each control unit 1-01 to C10 is connected to the programmer PRM via a communication unit CMU, and the target position data for each trolley 3-1 to 3-10 is transmitted to the programmer PRM).
Ra uke is taken. This communication unit hcMU may be connected to a host computer HCP, and receives and receives various setting data such as target position data from the host computer HCP, and receives and receives various setting data such as target position data from the host computer HCP.
The location data may be provided to the host computer HCP.

Each of the control units 01 to C1o includes sensor circuits sc1 to sc10 and positioning units PUI to PU10, respectively, which input the outputs of the corresponding position detection heads 6-1 to 6-10 to obtain absolute position data. Each positioning unit PUi to PU10 has a corresponding trolley 3-1.
Based on the target position data and position data of 3-1° to 3-1° and the position data of the adjacent carts 3-1 to 3-10, each cart is controlled so that it does not approach the adjacent cart abnormally. This is to control positioning to the target position. The motors M1 to M10 for driving the carts 6-1 to 3-10 are, for example, pulse motors, and the outputs of the respective positioning units PU1 to PUjQ are given to the pulse smoke drive units MDi to MD j Q, and the drive units MDl ~MD Each pulse smoke M1 to M10 is driven according to the output of 1Q.

An example of each of the control units 01 to C10 is shown in FIG. 5, with an arbitrary n-th control unit Cn as a representative. The output of the corresponding position detection head 6-n is sent to the sensor circuit SC.
, and absolute position data X0 indicating the current position of the corresponding truck 3-n is obtained from the sensor circuit SCn. This sensor circuit SCn has, for example, a function that combines the circuit shown in FIG. 3 and the arithmetic circuit of the third equation.

Of course, as described above, each sensor circuit SCo does not need to have all such circuit functions individually, and some circuit functions may be shared. The detected position data Xn is given to the positioning unit PUn corresponding to itself, and also given to the positioning units PU and PUn+ corresponding to the adjacent carts, respectively.

The input interface DIi inputs the target position data TXn corresponding to the trolley 3-n from the programmer PRM and supplies it to the positioning unit 1-PU port. The input interface DI, D-engine 3 is connected to the adjacent trolley 3n-
Sensor circuit SCn I r corresponding to 113n+1
Position data Xn-++ of the adjacent cart from SCn+1
Take each receiver of Xfi+1 and connect it to the positioning unit P.
Give to Uo.

In the positioning unit PUn, the subtracter 5UB1 is T
Perform the calculation Xn-Xn=l to determine the current position X with respect to the target position TX. Find the difference g.

Note that this difference j has a plus or minus sign. Speed setting section DE'l' 1 is the difference l and predetermined low speed width data/? a,
l! The speed command data is generated according to a predetermined normal running pattern depending on the relationship between the speed control and the speed control.b and lc. There are three types of speed command data: "high speed", "low speed", and "stop", and data indicating forward or reverse direction of travel is added to this data.

As an example, in order to eliminate positioning errors during forward and backward movement due to gear bank lash, positioning is performed in only one direction when finally stopping. That is, when positioning is performed by moving forward (in the positive direction), that is, the target position TX.

is larger than the current position I try to stop it when it happens.

To explain the positioning control in the forward direction in more detail with reference to FIG. 6 Ca), when the difference l is larger than the predetermined low speed width l, the robot is moved forward at "high speed" and l falls within the range of 11a. The robot switches to "low speed" and moves forward, and even when 1=o, it does not stop and continues to advance at "low speed", and stops when 1=-1b. Next, the traveling direction is changed to the opposite direction, the vehicle is moved backward at "low speed", and it is stopped when 1=o.

Regarding positioning control in the negative direction (backward direction), see Figure 6 (
To explain with reference to I)), when the difference l is negative, i<-
If #lo (that is, ll>lc), move backward at "high speed", and when l enters the range of -lo, switch to "low speed", l=o
It will stop when . In this way, in both forward movement and backward movement, positioning is ultimately performed in one direction (reverse direction).

In the speed setting section DET 1, the difference l and la, -lb, -4
According to the results of the comparison with .degree., speed command data is generated according to a normal running pattern as shown in FIGS. 6(a) and 6(b). First, the forward positioning control (Fig. 6(a)) is the first! 〉0. Here, l
If >la, "high speed" forward is instructed, then if l≦la, switch to "low speed" forward, even if 0≧J)-1b, "low speed" 1 forward is maintained, and 1=-lb. Stop when After a predetermined timer period has elapsed, it switches to reverse and starts, and in the range l≧-lb, it moves backward at “low speed” and 1=o(!
: Stop when On the other hand, the backward positioning control (6th
Figure (b)) is initially performed on the condition that 1<0.

Here, if l<-1c, a "high speed" retreat is instructed, and l≧
If it becomes -lo, it instructs to move backward at "low speed", and when it becomes 1=o, it stops. The speed command data generated from the speed setting section DET1 is supplied to the pulse motor and drive unit MDn via the priority circuit PRY.

The subtractor 5UB2.5UB3 is for finding the separation distance between adjacent bogies, and in 5UB2, by subtracting the position data Xn of the bogie closer to the backward direction from Xn, the distance 1n=Xn-X Find , , . 5
In UB3, the position data of the cart near the forward direction X n +
By subtracting Xn from 1, the distance 1n=X
Find n+, -X. The sign of the difference ln is always positive. The outputs of the stroke subtracters 5UB2 and 5UB3 are respectively gated],
It is input to G2. Data F/R indicating the forward/reverse direction is output from the speed setting section DET1, and the gate G1. G
given to 2. When moving forward, gate G2 is opened and 1
n=Xn+t-xn is the speed setting part DET for near miss prevention
2, and when reversing, gate G1 is opened and 1n
=xn This is because it is sufficient to consider the distance.

The near-miss prevention speed setting unit DET2 has a predetermined first clearance width l! , and the second clearance width 11z (however, l+>12) and inter-bogie distance data ln, a "low speed" command is issued in the range of I2<ln≦it, and a "stop" command is issued in the range of ln≦12. issue. The output of this setting section DET2 is given to the motor drive unit MDn via the priority circuit PRY. Priority circuit P
RY transfers the speed command data of setting section DET2 to setting section DET.
This is a circuit that gives priority to speed command data No. 1. For example, if the output of the setting unit DETj indicates high speed but the output of setting unit DET2 indicates low speed, the speed command data given to drive unit MD will indicate low speed. Further, even if the output of the setting unit DET1 indicates a low speed, if the output of the setting unit DET2 indicates a stop, the speed command data given to the drive unit l' MD n will instruct a stop.

FIG. 7 shows an example of the operation of the near-miss prevention speed setting section DET2. Position the N[15 truck (3-5) at the target position TX5 in the forward direction, and move the Yin 6 truck (3-5) to the target position TX5 in the forward direction.
3-6> is positioned at the target position TX6 in the backward direction, and in the process where N[15 moves forward and Nn6 moves backward, the distance between them becomes equal to the first clearance width 1.
．． When the speed is entered, the command speed of both will be forced to "low speed". The dotted line indicates the output of the speed setting section DETj. If the distance between the two target positions 'rx5' and 'rx6 is wider than the second clearance width 12, they are positioned at their respective target positions, but as in TX5', TX,', the distance between the two is narrower than 12. In this case, each vehicle is forcibly stopped when the distance between the two reaches 12 before the target position.

The near-miss prevention speed setting unit DET2 is configured to perform the above-mentioned condition determination according to a predetermined hysteresis characteristic. That is, the separation distance l.

But once l. The condition for starting at a low speed after being forced to stop due to ln>12 is when ln>12+α, and 1. After becoming ≦11 and being forced into a low speed state,
The condition for returning to normal operation (high speed) is ln>1. This is when it becomes +α. α is the hysteresis width.

In addition, when positioning is performed by starting all the bogies at the same time, a running pattern exclusively for simultaneous starts as shown in FIG. 8 may be adopted without performing speed control in the pattern shown in FIG. 6. For example, all the bogies are moved to a position that is lb closer to the forward direction F than their respective target positions TXn (the bogies traveling forward are lb).
First position the truck to a position where it overruns TXn by an amount b, and the truck moving backward is a position lb before TXn) (Fig. 8(a)), and then from that position all the trucks are simultaneously directed to their respective target positions TXn. Make it run backwards (Fig. 8 (5)). If both the normal travel pattern as shown in Figure 6 and the near miss prevention travel pattern as shown in Figure 7 are enabled during simultaneous positioning of all troops, near misses can be prevented at appropriate locations by each truck running asynchronously. It is possible that the conditions of the traveling pattern are met and the vehicle stops before reaching the target position. for example,
When the trolley 3-1 travels forward and stops at a position overrun by Ilb from the target position TX, and the adjacent trolley 3-2 travels backward and is exactly positioned at the target position TX2, the difference between the two, TX2- If (TXI +db) falls within the second clearance width 12, the truck 3-1 will stop due to the near-miss prevention travel pattern and will not move there. However, if a traveling pattern dedicated to simultaneous starts as shown in Fig. 8 is used, the trolley 3-2 can be stopped at a position 1 lb ahead of TX2, so the difference between the two is (T
X2+l l) ) (TX2 +ll b)=TX
2 TXH and the preset target position 'rx1
, 'rx2. Therefore, all carts can be positioned simultaneously without worrying about near misses. In order to control the running pattern exclusively for simultaneous start, it is necessary to further provide a control means in the control unit Cn, but illustration of this point is omitted.

Note that a fixed chain and sprocket may be used instead of the rack 4 and pinions 5-1 to 5-10 in FIG.
Alternatively, other self-propelled mechanisms may be used. Further, the trolley may not be self-propelled but may be manually operated.

〔Effect of the invention〕

As explained above, according to the present invention, the positions of a plurality of carts moving independently along a common guide are detected in an absolute manner, so that the carts do not interfere with each other or approach each other abnormally. so the position can be controlled. In addition, since the position detection head provided on each truck performs absolute position detection in response to a common position detection pattern, there is no need to adjust the origin between each head.
It has various advantages, such as eliminating the need for origin adjustment operations when replacing the gutter.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an embodiment of the present invention, FIG. 2 is a cross-sectional view showing a specific example of the position detection head 1 and the sensor rod in the same embodiment, and FIG. 3 is a measurement related to FIG. 2. FIG. 4 is a block diagram showing an embodiment 90 of the position control device according to the present invention, FIG. 5 is a block diagram showing a specific example of the control unit in FIG. The figure shows an example of a normal running pattern (speed pattern) realized by the speed control by the speed setting section for the normal running pattern in Fig. 5;
Figure 8 is a diagram showing an example of a running pattern for near miss prevention (speed pattern) realized by speed control by the near miss prevention speed setting section in the figure, and Figure 8 is a diagram showing an example of a running pattern for simultaneous start (speed pattern). , is. 1.2... Guide rail, 3-1 to 3-10... Agreement, 4... Rack, 5-1 to 5-10... Pinion, M
1 to M10・Motor, 6-1 to 6-10・Position detection head, 20 to 22 Sensor rod, M・Magnetic material, N
...Nonmagnetic material, sl, s2. s3...Sensor, 7-1
4 Coil, C1~C10...Control unit, sc1~
5C10・Sensor circuit, PU1~PU1o Positioning unit, MD1~MD10 Pulse motor 1 fixed unit.

Claims (1)

[Claims] 1. A plurality of carts movable independently along a common guide, a position detection pattern provided along the guide, and a position detection pattern attached to each cart and responsive to the pattern. and a position detection head for respectively detecting the absolute position of each cart on the guide. 2. A plurality of carts movable independently along a common guide; a position detection pattern provided along the guide; and a position detection pattern attached to each cart and responsive to the pattern for each cart in the guide. a position detection head for detecting the absolute position of each trolley, target position data set individually for each trolley, absolute position data for each trolley obtained based on the output of the position detection head, and a position adjacent to each trolley. The present invention is characterized by comprising positioning means for positioning each trolley at its corresponding target position based on the absolute position data of the trolleys being controlled so that each trolley does not approach abnormally close to an adjacent trolley. Position control device.