JP3198330B2 - Position detection sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position detecting sensor suitable for use in, for example, an autonomous traveling unmanned vehicle traveling on a multibranch road.

[0002]

2. Description of the Related Art Conventionally, a self-propelled unmanned vehicle or the like which travels on a straight road and a branch road to the left and right which is formed by sticking a guide tape GT made of a magnet as shown in FIG. As shown in FIG. 11, a plurality of magnetic switches S1 to SN, such as a saturable coil, a Hall element, a reed switch, and an MR element, which conduct according to magnetism, are arranged at a predetermined distance from each other as a position detection sensor. A device that detects the left and right positions of the unmanned vehicle in the width direction of the tape GT has been proposed.

In FIG. 11, GT is a guide tape made of a magnet, and S1 to SN are arranged in tandem with the guide tape GT, and are grounded by conduction according to the magnetism of the adjacent guide tape GT. RS is an output resistance connected in series with N + 1 switches across the magnetic switches S1 to SN. SW is a left / right switch, CS is a constant current source, and O
UT is an output terminal.

In such a position detecting sensor, when the left / right changeover switch SW is tilted to the left, for example, only the magnetic switch at the leftmost position facing the guide tape GT among the magnetic switch rows S1 to SN conducts, and the guide tape is turned on. G
By outputting a voltage along the leftmost end of T from the output terminal OUT, the left and right positions of the unmanned vehicle with respect to the left end of the guide tape GT can be detected. Similarly, when the left / right switch SW is turned to the right, the magnetic switch row S
Only the magnetic switch at the rightmost position opposing the guide tape GT among 1 to SN is turned on, and a voltage along the rightmost end of the guide tape GT is output from the output terminal OUT, so that the magnetic switch relative to the right end of the guide tape GT is output. The left and right positions of the unmanned vehicle can be detected.

As shown in FIG. 8, when the guide tape GT has left and right branch paths, the left / right switch SW is set in the same direction as the desired direction (left side in the left direction and right side in the left direction) before the branch path. If it is tilted to the right, the left and right positions of the unmanned vehicle with respect to the end of the guide tape GT in that direction (the left end in the left direction and the right end in the right direction) are detected. By controlling the position of the unmanned vehicle, the unmanned vehicle can enter a forked road in a desired direction. In addition, on a straight road without a branch, the position of the unmanned vehicle is controlled by controlling the position of the unmanned vehicle based on the detection result of the position with respect to the right end or the left end of the guide tape GT, regardless of which side the left / right switch SW is tilted. You can go straight.

[0006]

However, in such a conventional position detection sensor, for example, as shown in FIG.
Guide tape G on the floor on which guide tape GT is stuck
At the place where the reinforcing iron plate I wider than T is provided under the floor, the iron plate I causes the magnetic flux density distribution to be higher than the other parts as if the lateral width of the guide tape GT was widened. Spread becomes large.

In such a location, when the left / right selector switch SW is tilted to the left, the magnetic switch closer to the left than the leftmost magnetic switch facing the guide tape GT conducts, and the left / right selector switch SW moves to the right. Even when the guide tape GT is lying down, the magnetic switch on the right side of the rightmost magnetic switch facing the guide tape GT conducts, so that the left and right positions of the unmanned vehicle with respect to the left and right ends of the guide tape GT are more distant than they actually are. Is incorrectly detected at the position

If the position of the unmanned vehicle is controlled on the basis of such an erroneous position detection result, the unmanned vehicle will be displaced closer to the end of the guide tape GT than the expected position, and in an extreme case, the path of the unmanned vehicle Is deviated from above the guide tape GT.

The present invention has been made in view of the above points, and has a position detecting sensor capable of accurately detecting the left and right positions with respect to the guide tape GT even in a portion where the spread of the magnetic flux density changes due to the presence of an iron plate or the like. It is intended to provide.

[0010]

[0011]

[0012]

[0013]

A first position detecting sensor according to the present invention comprises a plurality of heads for detecting a traveling path, such as guide tapes GT, which are arranged apart from each other in the width direction of the traveling path. Means for driving these heads, based on the output of each head, means for generating left end information indicating the leftmost head of the heads turned on when driven, and based on the output of each head, Means for generating right end information indicating the rightmost head among the heads turned on when driven, and means for generating width information indicating the width between the leftmost head and the rightmost head, Means for using the width information to generate first offset information indicating 1/2 of the width between the leftmost head and the rightmost head;
And means for adding each the first offset information at the left end information and the right end information, the first offset information
To the left end information and right end information with
Means for adding the second offset information;
In the mode that branches left at the crossroads, the first offset
Left end information to which the offset information and the second offset information are added
As the position detection output, branch right on the fork
In the forward mode, the first offset information and the second
The right end information with the set information added is used as the position detection output,
In the mode in which the vehicle travels on a straight road, the first offset is used.
Left end information to which the default information and the second offset information are added,
Add first offset information and second offset information
Either of the right end information and the
Means for switching the position detection output . (In the present specification, turning on the head means that a signal indicating that the traveling path has been detected is output from the head.
This includes the case where the traveling path is actually detected and the case where something other than the traveling path (for example, the iron plate in FIG. 11 described above) is erroneously detected as the traveling path. )

According to the position detecting sensor, the heads arranged at a distance from each other in the width direction of the traveling path are driven, and left-end information and right-end information indicating the leftmost and rightmost heads that are turned on; Width information indicating the width between the leftmost head and the rightmost head is generated. Then, the first offset information generated by using this width information and indicating 1/2 of the width between the leftmost head and the rightmost head that are turned on is added to the leftmost information and the rightmost information, respectively. Will be added. Also, the left offset to which the first offset information is added
The edge information and the right edge information have second fixed offset values, respectively.
Packet information is added . Then turn left on the fork on the road
In the mode that branches to and proceeds, the first offset information
And the left end information to which the second offset information is added is located.
Output mode, and branch right on a fork
The first offset information and the second offset information.
Information is added to the position detection output,
In the mode of traveling on a straight road, the first offset information and
And the left end information to which the second offset information is added and the first offset information.
Right end with offset information and second offset information added
Information so that either one of the
The position detection output is switched.

The width information is, for example, as shown in FIG.
At a location where the spread of the magnetic flux density distribution changes due to the presence of an iron plate or the like, the content is different from other locations corresponding to the variation. As a result, information obtained by adding the first offset information to the left end information and the right end information is information indicating the center position of the row of heads that were turned on when driven, regardless of such a change. Accordingly, the position with respect to the traveling path is always accurately detected without being affected by such a change based on this information, so that the position control target can be controlled to a desired position. In addition, the first
The second offset information added to the left end information and the right end information to which the offset information is added is a fixed value, and it is not necessary to adjust the second offset information according to the width of the traveling path and the magnitude of the magnetic flux density. It is.

The second position detecting sensor according to the present invention is the same as the first position detecting sensor described above, wherein the second position detecting sensor travels on a straight road.
Mode (straight driving mode) and a mode (branch)
Mode) , the means for generating the first offset information in the straight-ahead mode uses the current width information as the first offset information. In the branch mode, constant first offset information is generated using only the width information held in the holding means.

[0017]

According to this position detection sensor, in the straight traveling mode, the offset information is always updated using the current width information. Therefore, the information obtained by adding the offset information to the left end information and the right end information is, for example, as described above. In FIG. 11 of FIG.
Both the location where the spread of the magnetic flux density distribution changes due to the presence of the iron plate and the like and the other locations have the same contents as indicating the position with respect to the center of the magnetic flux density distribution. Therefore, the position with respect to the center in the width direction of the traveling path is always accurately detected based on this information, so that the position control target can be controlled to the desired position and travel straight.

[0019] On the other hand, in the separation mode, it is held in the holding means
Since the constant offset information is generated using only the width information at the time of switching from the straight traveling mode to the branch mode, the information obtained by adding the offset information to the left end information and the right end information is respectively It indicates the position relative to the left and right ends of the road. Therefore, the position control object can be controlled to the desired position based on this information and can enter the left and right branch roads.

Further, the information obtained by adding the offset information to the left end information and the right end information at the moment when the mode is switched from the straight traveling mode to the branch mode matches the last information in the straight traveling mode. Sometimes, the position with respect to the traveling path is not erroneously detected.

[0021]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Figure 1 is a circuit diagram showing a first embodiment of the position detecting sensor according to the present invention.

{Detection Circuit of Magnetic Flux Density Distribution} In the width direction of the guide tape GT as shown in FIG. 10, detection heads H0 to H7 composed of saturable coils are arranged at a constant pitch. One end of each of the heads H0 to H7 is connected to a common signal line L. At the other end of each of the heads H0 to H7, FIG.
, Drive pulses P0 to P7 shifted in timing by a predetermined time T1 are repeatedly applied from the left head H0 to the heads H1, H2,... H7 sequentially toward the right head. Means for supplying such drive pulses P0 to P7 are not particularly shown, but for example, a clock pulse CLK having a period T1 generated by an oscillator and a frequency divider.
May be sequentially distributed to the signal lines on the other ends of the heads H0 to H7 using a multiplexer.

By driving the heads H0 to H7 with such drive pulses P0 to P7, according to the magnetic flux density distribution in the width direction of the guide tape GT (see FIG. 3),
A voltage signal _VH having an amplitude level proportional to the magnetic flux density at a position immediately below each of the heads H0 to H7 generates drive pulses P0 to P0.
It is sequentially obtained on the signal line L side at the timing of P7. FIG. 4 shows this voltage signal in a case where the heads H3 and H4 of the heads H0 to H7 are located directly above the guide tape GT.

The level of the voltage signal V _H is sequentially compared with a predetermined threshold value Vth by the comparator 1. R1 and C are resistors and capacitors connected to the connection points between the heads H0 to H7 and the comparator 1 on the signal line L, respectively, and their ends opposite to the signal line L are grounded. + V is a positive constant voltage source, and the threshold Vth is
A resistor R having one end connected to this voltage source and the other end grounded
By dividing the voltage of the voltage source with 2, is set lower than the level of the voltage signal V _H when the drive head located directly above the guide tape GT of head H0～H7 ( (See FIG. 4).

The output of the comparator 1 is applied to the D (data) input of the flip-flop 2. A clock pulse CLK having a period T1 is applied to a C (clock) input of the flip-flop 2. As a result, the comparison result of the comparator 1 at the timing of each of the drive pulses P0 to P7 is stored in the flip-flop 2 over the time T1 until the timing of the drive pulse P0 to P7 immediately after that.
, The serial data SD obtained by binarizing the voltage signal V _H into the H level and the L level is obtained from the flip-flop 2 as shown in FIG.

{Output Voltage Generation Circuit} (Left Branch Mode Output Voltage Generation Circuit) Serial Data S
D is input to the counter 3. The counter 3 has a period T
One clock pulse CLK is counted, the count value _BL at the moment when the serial data SD rises from the L level to the H level is latched, and an initial value is set for each repetition period T2 (see FIG. 2) of the drive pulses P0 to P7. Reset to value 0.

Since the drive pulses P0 to P7 are sequentially applied to each of the heads H0 to H7 from the head H0 on the left side of FIG. 1, the head which sets the serial data SD to the H level by the count value _BL of the counter 3 is used. H0-H7
Which head (ie, the head that has been turned on) is at the leftmost end. In the example of FIG. 5, since the count value _BL is 3, the head H that is three places to the right of the head H0
It can be seen that No. 3 is the leftmost head.

The output of the counter 3 is supplied to a D / A converter 4
_Is converted to an analog voltage V _LDA . The D / A converter 4 outputs, for example, a unipolar voltage proportional to the value of the input signal. Therefore, assuming that the voltage conversion coefficient is K, V _LDA = K · B _L (1)

An offset voltage V _OF for adjusting the center value of the left branch mode output voltage is _added to the analog voltage V _LDA.
Are added by the adder 5 to generate the left branch mode output voltage _VL . The offset voltage V _OF is a resistor R having one end connected to the negative constant voltage source -V and the other end grounded.
3 by dividing the voltage of this voltage source. V _L = V _LDA + V _OF (2)

The left branch mode output voltage _VL is applied to the fixed contact a1 of the changeover switch 6. The mode selection switch 7 controls the position of the unmanned vehicle on the branch road of the guide tape GT to enter a left branch road, and a left branch mode.
In order to select a desired mode from a right branch mode in which the position of the unmanned vehicle is controlled on the branch road of the guide tape GT and the vehicle enters the right branch, and a straight traveling mode in which the unmanned vehicle is controlled on a straight road and travels straight. When the left branch mode is selected by the mode selection switch 7, the switching circuit 8 changes the movable contact b of the changeover switch 6 to the fixed contact a.
By switching to the 1 side, the left branch mode output voltage _VL is output as a detection result of the position detection sensor.

The value of the offset voltage V _OF is, for example, such that the left branch mode output voltage _VL when the center of the row of the heads H0 to H7 coincides with the center in the width direction of the guide tape GT is 0V. (Accordingly, when the center of the row of the heads H0 to H7 is on the left and right sides of this center of the guide tape GT, the left branch mode output voltage _VL is minus, respectively.
(Positive value). Therefore, (1)
From the formulas and the formulas (2), V _OF = 0−K · B _L = −K · B with respect to the count value B _L when the center of the row of the heads H0 to H7 coincides with this center of the guide tape GT. _L ... (3)

For example, FIG. 6 shows the on / off state of each of the heads H0 to H7 in the case of FIG.
The center of the row of H7 is the center C in the width direction of the guide tape GT.
It can be seen that they match. Accordingly, in this case, since B _{L in} equation (3) is 3, V _OF = −3K (4).

On the other hand, the spread of the magnetic flux density distribution is shown in FIG.
When the center of the row of the heads H0 to H7 coincides with the center C in the width direction of the guide tape GT, for example, the head H2 is turned on as shown in FIG. If it is at the left end, since B _{L in} equation (3) is 2, V _OF = −2K (5).

Therefore, the offset voltage V _OF needs to be set in advance to different values according to the width of the guide tape GT.

(Right Branch Mode Output Voltage Generation Circuit) The serial data SD is also input to the counter 9. The counter 9 starts the clock pulse CLK having the period T1 from the moment when the serial data SD falls from the H level to the L level.
Is counted, and the count value _BR is latched and reset to the initial value 0 at each repetition period T2 (see FIG. 2) of the drive pulses P0 to P7.

Since the drive pulses P0 to P7 are sequentially applied to the respective heads H0 to H7 from the head H0 on the left side of FIG. 1, the serial data SD falls from the H level to the L level retroactively from the last drive pulse P7. By counting the number of pulses up to the drive pulse, it is possible to determine which of the heads H0 to H7 (that is, the heads that have been turned on) in which the serial data SD has been brought to the H level is the rightmost end. However, in practice, it is impossible to count backwards in time, so counting is performed like this counter 9 and the count value BR indicates the rightmost head. In the example of FIG. 5, since the count value BR is 3, it can be seen that leftward head H 4 3 one of the head H7 is the rightmost head.

The output of the counter 9 is supplied to the D / A converter 4
_Is converted to an analog voltage V _RDA by the D / A converter 10 having the same voltage conversion coefficient K. _{V RDA = K · B R ...} (6)

An offset voltage V _OF for adjusting the center value of the right branch mode output voltage is _added to the analog voltage V _RDA.
Are added by the adder 11, and the output of the adder 11 is
By factor-1 is multiplied by 2, the right branch mode output voltage V _R of the same inclination as the left branch mode output voltage V _L is generated. V _R = over _{(V RDA + V OF) ...} (7)

The output voltage V _R the right branch mode is added to the fixed contact a3 of the switch 6. When the right branch mode is selected by the mode selection switch 7, the movable contact b of the switch 6 is switched to the fixed contact a3 by the switching circuit 8, so that the right branch mode output voltage V
_R is output as a detection result of the position detection sensor.

It should be noted that also in this case, the offset voltage V_OFThe value of the
Is that the center of the row of heads H0 to H7 is the guide tape GT
Right branch mode output voltage when it matches the center in the width direction
V_RIs set to be 0V. Therefore, equation (6)
From equations (7) and (7), the center of the row of heads H0 to H7 is
Count value B when coincident with this center of tape GT
_RFor V_OF= 0-KB_R= -KB_R ... (8)

For example, in the case of FIG. 5, since B _{R in} equation (8) is 3, as shown in FIG. 6, V _OF = −3K (9).

On the other hand, as shown in FIG. 7, when the head H5 among the heads turned on is at the rightmost end,
Since B _{L in} equation (8) is 2, V _OF = −2K (10)

From the equations (4) and (5) and the equations (9) and (10), the offset voltage V _OF for the right branch mode output voltage V _R is equal to the offset voltage V _OF for the left branch mode output voltage V _L. Although it is not necessary to make the value different from the offset voltage V _OF , it is understood that it is necessary to set the value in advance according to the width of the guide tape GT.

[0044] (generation circuit of the rectilinear mode output voltage) as described above, the value of the offset voltage V _OF is (a) the output voltage V _L, or adjusts the center value of V _R many V (b) guide the tape It is set by combining two factors, that is, how wide the GT is.

Accordingly, as long as only the magnetic flux density distribution caused by the guide tape GT is detected (referred to as a standard use state), the left branch mode output voltage V _L and the right branch mode output voltage V _R Guide tape G
Since the position of T with respect to the left and right edges is accurately detected,
The unmanned vehicle can be controlled to the expected position and enter the left and right forks. Further, even on a straight road, the left branch mode output voltage _VL or the right branch mode output voltage V _R
The unmanned vehicle can be controlled to a desired position and run straight by accurately detecting the position with respect to the left end or the right end of the guide tape GT by any one of the output voltages.

However, for example, in a place where an iron plate or the like exists as shown in FIG. 11, the magnetic flux caused by this iron plate or the like causes the magnetic flux density distribution to be higher than in other places as if the width of the guide tape GT was widened. Is spread (that is, the state deviates from the standard use state).

Here, taking the case where the on / off state of each of the heads H0 to H7 in the standard use state and the state deviating from the standard use state as shown in FIGS.
The left branch mode output voltage V _L and the right branch mode output voltage V _R in each case are specifically calculated as follows.

In the state of FIG. 8A, the count values B _L and B
_R is 4, 2 respectively. Since the state where the center of the row of the heads H0 to H7 coincides with the center C in the width direction of the guide tape GT while the spread of the magnetic flux density distribution is equal to that in FIG. 8A is the same as the state in FIG. V
The value of _OF is -3K from equation (4).

Therefore, from the equations (1) and (2), V _L = K · B _L + V _OF = K · 4−3K = K (11), and from the equations (6) and (7) , V _R = − (K · B _R + V _OF ) = − (K · 2−3K) = K (12)

On the other hand, in the case of FIG. 8B, the count values B _L and B _R are 3 and 1, respectively. Also, the value of the offset voltage V _OF remains at −3K set in the standard use state of FIG. 8A.

Therefore, V _L = K · B _L + V _OF = K · 3−3K = 0 (13) V _R = − (K · B _R + V _OF ) = − (K · 1−3K) = 2K (14)

[0052] (13) and (14) As is apparent from the expression, in a state in which off-standard use, the left branch mode output voltage V _L, the right branch mode output voltage V _R is different from the normal use state Since the value becomes the value, the position with respect to the left end and the right end of the guide tape GT is erroneously detected.

[0053] straight mode, such standard used is provided in order to avoid erroneous detection of a state in which off-state, the left branch mode output voltage V _L and the right branch mode output voltage V _R and an adder 13, and the output of the adder 13 is multiplied by a coefficient で by the multiplier 14 to obtain the straight-running mode output voltage VS. VS = (V _L + V _R ) / 2 (15)

[0054] That is, the straight mode output voltage VS is obtained by averaging the left branch mode output voltage V _L and the right branch mode output voltage V _R, therefore, the head turned on among the heads H0~H7 It indicates the center position of the column.

When the straight mode output voltage VS is specifically calculated by taking the states of FIGS. 8A and 8B as an example, in the case of FIG. 8A, from the equations (11) and (12), VS = (K + K) / 2. (16) = K, and in the case of FIG. 8B, from the expressions (13) and (14), VS = (0 + 2K) / 2 (17) = K

As is apparent from the equations (16) and (17), the output voltage VS of the straight-traveling mode can be obtained even in the standard use state.
Even in a state deviating from the standard use state, both values indicate the same position as the position with respect to the center of the magnetic flux density distribution.

This straight mode output voltage VS is applied to the fixed contact a2 of the changeover switch 6. When the straight traveling mode is selected by the mode selection switch 7, the movable contact b of the switching switch 6 is switched to the fixed contact a2 by the switching circuit 8, so that the straight traveling mode output voltage VS is output as a detection result of the position detection sensor. You. Therefore, even if there is a portion on the straight road where the spread of the magnetic flux density distribution changes, the unmanned vehicle is controlled to the expected position while accurately detecting the position with respect to the center in the width direction of the guide tape GT. You can go straight.

Next, FIG. 9 is a circuit diagram showing a second embodiment of the position detecting sensor according to the present invention (an embodiment corresponding to the above-described first and second position detecting sensors according to the present invention). In this figure, the same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

(Detection Circuit of Spread of Magnetic Flux Density Distribution) This position detection sensor is provided with a counter 15 in addition to the counters 3 and 9, and serial data SD from the flip-flop 2 is also input to the counter 15. You.

The counter 15 indicates that the serial data SD is L
The clock pulse CLK of the cycle T1 is counted from the moment when it rises from the H level to the H level.
While latching the count value BW at the moment when D falls from the H level to the L level, the drive pulse P0
The initial value is reset to 0 every repetition period T2 (see FIG. 2) of P7.

Based on the count value BW, the width (ON) between the head at the leftmost end and the head at the rightmost end of the heads H0 to H7 (that is, the heads turned on) in which the serial data SD is set to the H level. (Referred to as the on-bit width in the sense of the width of the head). For example, in the state shown in FIG. 8A, the count value BW
8B, the count value BW (on bit width) is 3 in the state shown in FIG. 8B. As described above, the on-bit width has a different value in accordance with the variation of the spread of the magnetic flux density distribution, whereby the current spread of the magnetic flux density distribution is determined.

[0062] In the position detecting sensor shown in FIG. 1 (setting circuit of the offset voltage V _W corresponding to the spread of the magnetic flux density distribution), as described above, (b) the output voltage V _L, the central value of V _R What V. (b) What is the width of the guide tape GT (that is, how large is the spread of the magnetic flux density distribution in the standard use state)? The value of the voltage V _OF is set.

On the other hand, in the position detection sensor shown in FIG. 9, an offset voltage corresponding to the spread of the magnetic flux density
Output voltage V _L, and an offset voltage for adjusting the center value of V _R is set separately.

That is, the output of the counter 15 is converted into an analog voltage by the D / A converter 17 of the voltage conversion coefficient K via the hold circuit 16 (control of the hold circuit will be described later), Coefficient 1/2
, An offset voltage V _W indicating a width corresponding to の of the on-bit width is obtained. V _W = K · BW / 2 (18)

The offset voltage V _W is added to the adder 19,
At 20, they are added to the analog voltages V _LDA and V _RDA from the D / A converters 4 and 10, respectively. Analog voltage V
_LDA and _VRDA indicate the heads at the leftmost and rightmost ends, respectively, of the heads turned on as described above. By adding the indicated information, information indicating the center position of the row of heads that are turned on can be obtained.

The output of the adder 19 includes the center value of the output voltage.
Offset voltage V for adjusting _OC(One end is negative constant current
Using a resistor R4 connected to the pressure source -V and having the other end grounded
It is obtained by dividing the voltage of the lever voltage source.
) Are added by the adder 21, whereby the left branch mode
Output voltage V_LIs generated. V_L= V_LDA+ V_W+ V_OC (19) The output of the adder 20 also has the offset voltage V
_OCIs added by the adder 22, and the output of the adder 22 is
23 is multiplied by a coefficient -1 to produce a left branch mode.
Output voltage V_LRight branch mode output voltage V with the same slope as_RBut
Generated. V_R=-(V_RDA+ V_W+ V_OC)… (20)

When the center of the row of the heads H0 to H7 coincides with the center in the width direction of the guide tape GT, the offset voltage V for setting the left branch mode output voltage _VL to 0V.
_{From the} equations (1), (18) and (19), the value of _OC is given by: V _OC = V _L −V _LDA −V _W = 0−K · B _L −K · BW / 2 = −K · BA /2...(21) However, BA = a _{B L + BW + B R ...} (22), will be referred to as all bit width the BA in the sense that the width of the head H0 to H7 (see Figure 8).

[0068] The value of the offset voltage V _OC to the right branch mode output voltage V _R to 0V when the center of the row of heads H0~H7 matches the center of the width direction of the guide tape GT is ( 6), (18), (20) and (22) from the equation, V _OC = over V _R over V _RDA over V _W = 0 over K · B _R over K · BW / 2 = over K · BA / 2 (23), which is equal to the value of the offset voltage V _OC for the left branch mode output voltage _VL .

Therefore, the left branch mode output voltage V _L is
From equations (1), (18), (19), (21) and (22), V _L = K · B _L + K · BW / 2−K · BA / 2 = K · B _L + K BW / 2−K · (B _L + BW + B _R ) / 2 = K · (B _L −B _R ) / 2 (24), and the right branch mode output voltage V _R is expressed by the following equation (6).
(18), (20), (22) and from (23), V _R = over _{(K · B R + K ·} BW / 2 -K · BA / 2) =-K · B _R-K · the BW / 2 + K · (B L + BW + B R) / 2 = K · (B L over _{B R) / 2 ... (25} ).

(Generation of the output voltage in the straight traveling mode) As is clear from the equations (24) and (25), the left branch mode output voltage V _L and the right branch mode output voltage V _R have the same value. Is the analog voltage V _LDA ,
By adding the offset voltage V _W to V _RDA , both the left branch mode output voltage V _L and the right branch mode output voltage V _R indicate the center position of the row of heads that are both turned on. is there.

Therefore, if the left branch mode output voltage V
_L, even determine the advance mode output voltage VS by the right branch mode output from the voltage V _R of the above (15), was also matched with the original left split mode output voltage V _L and the right split mode output voltage V _R It is not necessary to obtain the straight-running mode output voltage VS because it is only a value.

Therefore, this position detection sensor does not include a circuit for generating a straight-running mode output voltage (corresponding to the adder 13 and the multiplier 14 in the position detection sensor of FIG. 1). V _L and the right branch mode output voltage V _R the left split mode output voltage as an example in it has (Fig. 9 is added to the fixed contact a2 of the switch 6 any one as a straight mode output voltage VS of the V _L
Is added to the fixed contact a2).

When the straight mode is selected by the mode selection switch 7, the input signal is passed through without instructing the hold circuit 16 to hold the input signal, so that the offset voltage V _W to be generated is reduced. It is sequentially updated according to the current on-bit width (the current spread of the magnetic flux density distribution). Thus, the left branch mode output voltage V _L and the right split mode output voltage V _R is
In both the standard use state and the state deviated from the standard use state (for example, in FIG. 11 described above, at the place where the spread of the magnetic flux density distribution changes due to the presence of the iron plate or the like, or at any other place), the center of the magnetic flux density distribution is Are the same values indicating the position with respect to. Therefore, even if there is a portion on the straight road where the spread of the magnetic flux density distribution changes, the unmanned vehicle is controlled to the expected position while accurately detecting the position with respect to the center in the width direction of the guide tape GT. You can go straight.

(Generation of Left Branch Mode Output Voltage and Right Branch Mode Output Voltage) On the other hand, when the left branch mode or the right branch mode is selected by the mode selection switch 7 due to the approach from the straight road to the branch road, until then. left branch mode output voltage V _L the same way as the straight mode, even seeking right split mode output voltage V _R, the left end of the guide tape GT, the position relative to the right end is not detected, enters the unmanned vehicle to the branch path I can't let that happen.

Therefore, in this position detecting sensor, the same signal as the changeover circuit 8 of FIG. 1 is supplied to the changeover switch 6 in each mode, and the signals S1 and S2 are supplied to the OR circuit 24 in the left branch mode and the right branch mode, respectively. A switching circuit 25 for supplying one input and the other input is provided instead of the switching circuit 8, and the output of the OR circuit 24 is supplied to the control input of the hold circuit 16 as a control signal for instructing to hold the input signal. Is done.

In the left branch mode and the right branch mode, the hold circuit 16 is instructed to hold the input signal, so that the on-bit width at the time of switching from the straight mode to the branch mode is reduced. , So using only this on-bit width,
An offset voltage V _W fixed to a constant value is generated.

Accordingly, at this time, the left branch mode output voltage V _L and the right branch mode output voltage V _R are the positions with respect to the left end and right end of the guide tape GT as in the position detection sensor of FIG. 1 in which the offset voltage is fixed. Respectively. Therefore, the left branch mode output voltage V _L ,
May be advanced left, the branch of the right to control the intended position unmanned vehicle respectively by the right branch mode output voltage V _R.

Further, at the moment when the mode is switched from the straight mode to the branch mode, the left branch mode output voltage V _L generated by adding the offset voltage V _W and the offset voltage V _OC to the analog voltages V _LDA and V _RDA , and the right branch Mode output voltage V
_R, the last of the left split mode output voltage V _L in the straight mode, the match the value of the right branch mode output voltage V _R, is nor erroneously detected position with respect to the guide tape GT when switching modes .

In each of the above embodiments, the present invention is applied to a position detection sensor mounted on an unmanned vehicle traveling on a guide tape GT affixed to the floor surface. For example, a traveling path is formed by using a magnetized body as a member constituting the floor itself, or a traveling path is formed by arranging a large number of small magnetized bodies on the floor in an array state or embedding it in the floor. It is needless to say that the present invention can be applied to a position detection sensor mounted on an appropriate position control target that travels on a vehicle that travels on the vehicle.

In each of the above embodiments, the heads H0 to H
Although the head 7 is constituted by a saturable coil, these heads may be constituted by other appropriate elements (for example, Hall elements, MR elements, reed switches, etc.). The number of heads is not limited to eight, but may be an appropriate number.

In the second embodiment (an embodiment corresponding to the first and second position detection sensors according to the present invention) of the above embodiments, the on-bit width is determined by counting the clock pulses CLK. However, the on-bit width may be obtained by subtracting the count values BL and BR from the total bit width BA based on the equation (22).

In the second embodiment, the heads H0 to H7 are the same as in the first embodiment.
Are sequentially applied to the position detection sensor. However, the first and second position detection sensors according to the present invention generate width information indicating the width between the leftmost head and the rightmost head among the heads turned on based on the output of the head. Therefore, the present invention may be applied to a position detection sensor that drives all the heads at the same time.

The present invention is not limited to the above embodiment,
It goes without saying that various other configurations can be adopted without departing from the gist of the present invention.

[0084]

As described above, according to the position detection sensor according to the present invention, even in a place where the spread of the magnetic flux density distribution changes on the traveling road (for example, a place where an iron plate exists in FIG. 11), the change can be prevented. Regardless, there is an effect that the position with respect to the traveling path can be accurately detected. Therefore, even in such a location, a position control target such as an unmanned vehicle equipped with the position detection sensor can be controlled to a desired position.

Further, on a traveling road having various widths or a traveling road having various magnetic flux densities, by using one position detection sensor as it is, it is possible to accurately detect a position with respect to the traveling road. To play. That is, it is also possible to provide a plurality of types of position detection sensors according to the width of the traveling path and the magnitude of the magnetic flux density, or to set the offset value of one position detection sensor according to the width of the traveling path and the magnitude of the magnetic flux density. Neither adjustment is required. In addition, even if the magnitude of the magnetic flux density detected by the head changes due to a change in the distance between the head and the running path according to the unevenness of the running path or the weight of the cargo loaded on the unmanned vehicle, the change also occurs. It is not necessary to adjust the offset value according to. Therefore, the cost can be reduced by reducing the types of the position detection sensors, and the convenience at the time of using the sensors can be improved.

[0086]

According to the second position detecting sensor of the present invention, the information obtained by adding the offset information to the left end information and the right end information at the moment when the mode is switched from the straight traveling mode to the branch mode is obtained by the straight traveling mode. Therefore, the position with respect to the traveling path can be accurately detected even when switching from the straight traveling mode to the branching mode. Therefore, there is an effect that a position control target such as an unmanned vehicle can be controlled to an expected position and can enter a left or right branch road.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a drive pulse.

FIG. 3 is a diagram illustrating an example of a magnetic flux density distribution.

FIG. 4 is a diagram illustrating an example of output of each head.

FIG. 5 is a diagram illustrating an example of serial data SD.

FIG. 6 is a diagram illustrating an example of an on / off state of each head.

FIG. 7 is a diagram illustrating an example of an on / off state of each head.

FIG. 8 is a diagram illustrating an example of an on / off state of each head.

FIG. 9 is a circuit configuration diagram showing another embodiment of the present invention.

FIG. 10 is a plan view illustrating an example of a traveling path of an unmanned vehicle.

FIG. 11 is a circuit configuration diagram showing an example of a conventional position detection sensor.

[Explanation of symbols]

 GT guide tape H0-H7 Detection head 1 Comparator 2 Flip-flop 3, 9, 15 Counter 4, 10, 14, 17 D / A converter 5, 11, 13, 19, 20, 21, 22 Adder 6 Changeover switch 7 Mode Selection switch 8, 25 Switching circuit 12, 14, 18, 23 Multiplier 16 Hold circuit 24 OR circuit

Claims (2)

(57) [Claims] 1. A position detection sensor for detecting a position in a width direction of a traveling path, wherein the plurality of heads for traveling path detection are arranged apart from each other in the width direction of the traveling path; Means for driving, based on the output of the head, means for generating left end information indicating the leftmost head among the heads turned on when driven, and driven based on the output of the head Means for generating right end information indicating the rightmost head of the heads turned on, and means for generating width information indicating the width between the leftmost head and the rightmost head, Means for generating, using the width information, first offset information indicating a half of the width between the leftmost head and the rightmost head; and transmitting the first offset information to the left end information. And said And means for adding the respective end information, the leftmost information obtained by adding the first offset information and
The right end information includes second fixed offset information.
In the mode for adding the information and in the mode in which the branch road on the traveling road branches left and proceeds,
The first offset information and the second offset information
The added left edge information is used as a position detection output, and
In the mode in which the upper fork is branched to the right and proceeds, the first
Before adding offset information and second offset information
The right end information is used as the position detection output, and
In the mode that proceeds, the first offset information and the second
The left end information to which the offset information of
Before adding offset information and second offset information
Either one of the right end information is used as the position detection output.
And a means for switching the position detection output . 2. The position detection sensor according to claim 1, further comprising a holding unit for holding the width information at a time point when the mode is switched from the mode of traveling on the straight road to the mode of traveling on the branch road , means for generating the first offset information, the straight line
In the traveling mode, the first offset information to be generated is sequentially updated by using the current width information, and the traveling direction of the branch road is updated.
In a second mode, a fixed first offset information is generated using only the width information held by the holding means.