JPS5979114A - Detector for absolute line position - Google Patents

Abstract

PURPOSE:To detect absolute line positions in a wide range, by combining the integral of the number of cycles of a detection output signal of a detection object for an origin and current output signals. CONSTITUTION:Plural detecting parts S1 and S2 which generate electric output signals in prescribed cycles corresponding to mechanical displacement quantities different from each other with respect to the mechanical linear displacement of the detection object and an operating means COM which uses the difference of cycle between detecting parts and output signals of respective detecting parts to obtain the number of cycles from the origin of the detection object to the current position with respect to prescribed one of detecting parts S are provided. The absolute position of the detection object is specified by the combination between the integral of the attained number of cycles and the output signal of the prescribed detecting part S.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an absolute linear position detection device that expands the absolute detection range.

A well-known linear position detector (or transducer) that converts the mechanical linear position of an object to be detected into an electrical signal is a differential lance, which is currently being applied for by the present applicant. There is one disclosed in No. 56-22075. The disadvantage of these methods is that the measurable range is limited to a relatively narrow range. Therefore, Jitsugan Sho 57-32], No. 27 Mei 1% Ij
In book 1, multiple cores are provided at predetermined intervals in the core part that moves relative to the pick amplifier part consisting of the primary coil and secondary coil to expand the measurable range.
It is proposed that the However, in the prior application, the measurable range is expanded or only the linear position within one circumference of each core can be detected, and the range that can be detected by Absolute 1 is expanded. It wasn't that I was disappointed.

This invention has been developed in view of the above points,
Detection of AFSOLU-1/linear position over a wide range 1~
The aim is to provide a device that can obtain the desired results. According to this invention, a plurality of detecting sections are provided which generate output signals at a predetermined cycle in response to a change in mechanical linear position, and each detecting section generates an output signal at a predetermined period or depending on a different amount of mechanical displacement. You will be asked to respond accordingly. As a result, a predetermined deviation occurs in the value of the output signal of each detection unit with respect to the linear position of the detection target, and by calculating this deviation, a predetermined deviation in the value of the output signal of the detection unit that moves to the origin of the detection target occurs. The absolute position of the detection target is determined by matching the integer part of this cycle 1tJ] with the current output signal of the detection unit (value within 1 cycle + 01). I can be identified.

Embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As the simplest example, an example using two linear sensors will be explained in principle with reference to FIG.

A linear sensor 81 that generates an electrical output signal at a predetermined period in response to a mechanical linear displacement. As S2, a structure in which a plurality of cores are provided at predetermined intervals as shown in, for example, the specification of Utility Model Application No. 57-32127 is used. One sensor S
The amount of mechanical displacement of the detection target corresponding to one period of the output signal of one cell S2 is Pl, and the total amount of mechanical displacement of the detection object corresponding to one period of the output signal of the other cell S2 is P2. The invention is characterized in that the amount of mechanical displacement of the detection target corresponding to one period of the output signal of each sensor is made different, so it can be expressed as PI\P2.Each sensor S1, S2
It is possible to detect the absolute position (within one cycle (objective absolute position)) within the range of mechanical linear displacements P1 and P2 for each cycle.

In each sensor, Sl is N, as an output signal for one cycle,
Assume that S2 generates a value of N2.

In other words, in the case of a digital type, sensor S1 generates an afsolute output signal with an accuracy of one period divided by N1,
S2 generates all absolute output signals with an accuracy of dividing one round by N2.

In other words, when the mechanical displacement of the object to be detected is P, the sensor S1 outputs an output for one cycle,
At P2, the sensor S2 outputs the maximum output N2 for one period. When the amount of mechanical displacement of the object to be detected from the origin is J)I or 22 or more, the sensors Sl and S2 alone can determine how many cycles from the origin their output signals are, and the absolute position is detected. I can't come. However, if the output signals of this sensor 81.S2 are used in combination as shown in the image below, the absolute position can be determined.

Similarly, the iron of sensor S2,
Considering the case where the detection target moves P1 from the origin (at the origin, outputs of sensor Sl and S2 are both 0),
The output of the sensor S is N1, which is exactly 1υ1 minutes per revolution. In addition, the output of the sensor 82 is the value of the output signal obtained from the sensors Sl and S2, and when expressed as one, D + , D 2 at absolute 1 position Pl.
becomes as follows.

D,=N.

From this, it is clear that for each period of linear displacement P1 of sensor S1, the value of the output signal between field sensors S1 and 82 shifts sequentially according to the change (constant) in the lower part. Here D1□=0. -”tsu.

shall be.

Therefore 1. The arithmetic unit COM ; calculates the difference [D1
□Second, -D2J is calculated and divided by the constant in equation (2) above as shown below, then the current output signal D1 of sensor S1 is at what number u-th (Cx), counting from the origin. It turns out that it is.

Cx −D 12÷1'J + "P2"2
” ”' l ,,, (:3)2 The period obtained by the above equation (3), the period obtained by combining the regular part of the Cz and the output signal D1 of the sensor S1 (that is, the period obtained by the equation (3) FIG. 2 shows an example in which the sensors 81 and S2 are configured by phase shift type linear position detectors. First, to explain about the processor S1, the processor S1 includes a primary coil and a secondary coil housed in a predetermined arrangement in a casing 4-1, and a long core inserted into these coils so as to be linearly movable. Part 2
-1. The core part 2-1 includes a plurality of cores 3-1 arranged at predetermined intervals in the axial direction, a spacer 5-1 provided between each core 6-1, and these cores 6-1 and the spacer. It includes a sleeve 6-1 that covers the periphery of the sleeve 5-1. The core 6-1 is made of a magnetic material, and the spacer 5-1 is made of air or other non-magnetic material.

This core part 2-1 has a cylindrical shape (not applied from the outside as a detection target), and the length of the spacer 5-1 is the length of the core part 6-1.
approximately equal to the length of 1. Therefore, the distance for one pitch in the arrangement of the cores 6-1 is "Pl". In this implementation, the coils are arranged to operate in four phases. For convenience, these phases are distinguished using the symbols A, B, C, and D.

The reluctance generated in each phase A-D is shifted by 90 degrees depending on the position of the core 6-1. For example, if phase A is a cosine phase, phase B is a sine phase, phase C is a minus cosine phase, The C phase is set to have a negative sign.

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 14 of each phase A-D
Knee j: This is the primary knee corresponding to each. Figure 2? lJ
In this case, an A-phase coil 7.11 and a C-phase coil 9, 16 are provided adjacent to each other, and a B-phase coil 8, 12 and a C-phase coil 10.14 are also provided adjacent to each other. There is. The distance between the coils of phase A and phase B or phase C and phase C is P, (n
, 4'' (1! is any natural number).

Further, the arrangement of the coils of each phase A to D in the processor 1 is not limited to that shown in FIG. That is, the core part 2-
The reluctance of the magnetic circuit in each phase A-D- changes according to the linear displacement of 1, and the phase of the reluctance change shifts by 90 degrees for each phase m (therefore, the phase of the human face and C
The phase is shifted by 180 degrees, and the phase B and phase C are also shifted by jso+i), so it is only necessary to use a material that brings about such a reluctance change.

Primary coils 7 to 10 and secondary coil 11 in Fig. 2
-14 are connected as shown in FIG. 3, for example. Figure 3 shows the primary coils 7 and 9 of the A phase and C phase at a sine signal ratio ωt.
The secondary coils 11 and 16 are excited in opposite phases to each other by
This shows a wiring format in which the outputs of the two are added in phase. Similarly to the above, the B phase and D phase also have the primary coil 8,
10 is excited in reverse phase by the cosine signal part ωt, and the secondary coil 12
, 14 are added in phase.

In short, the wiring format shown in FIGS. 3 and 3 can be expressed as follows.

That is, two phases (A and C or B and D) whose reluctance changes are shifted by 180 degrees are operated in opposite phases, and two pairs whose reluctance changes are shifted by 90 degrees (A and C) are operated in opposite phases.
and the pair B and D), one is excited by the sine signal sInωt, and the other is excited by the cosine signal part ωt. In other words, the two pairs (the pair A and C and the pair B and D) are
It is the same as two differential lances whose reluctance changes are out of phase by 90 degrees. :Thus, each is excited individually.A, C phase pair and B.

The sum of the secondary coil outputs of the D-phase pair is sensor S1.
The secondary side output signal becomes ¥1. This output signal ¥1 is obtained by shifting the phase of the reference AC signal 'Csinωt or ωt) by a phase angle φ corresponding to the straight line position of the core portion 2-1. The reason for this is that the reluctance of each phase A to D is shifted by 90 degrees, and the electrical phases of the excitation signals of one pair (A, C) and the other pair (B, D) are shifted by 90 degrees. It's for a reason. This point can be expressed briefly as follows.

That is, the phase corresponding to the linear position of the core part 2-1 is φ
1, the function of the change in roughtance depending on the linear position can be expressed as follows: A phase is ωSφ1, B phase is sinφ1, C phase is 1匪φI, and D phase is −sinφ. The human phase and C phase are operated in opposite phases to each other by a sine signal sin ωt, and the B phase and D phase are operated in opposite phases to each other by a cosine signal part ωt, and the resulting secondary coil outputs are additively combined. Therefore, the output signal Y can be substantially expressed in the following informal formula.

Y 1= sinωtcosφ1−(sinωtcos
φ, ) + residence ω and old man φ, - (-jun ωt sinφ1 )”
= 2 sin ωt cos φ1 + 2 cos ωt sin
φ.

= 2 sin (ωt+φ,) If the coefficient indicated as “2” in the above formula is replaced with a constant determined according to various conditions, Y, = Ks+n(
It can be expressed as ωt+φ1). Here, the phase φ of the reluctance change is proportional to the linear position ), it is possible to detect the straight position #X by measuring the [standing deviation φ]. However, when the phase shift amount φ1 is full width 2π,
Corresponds to the linear position or the above-mentioned distance P ((one pinch length of the core 6-1).

That is, according to the electrical phase shift amount φ1 in the signal Y, the relative linear position within the range of the distance P1 can be detected.

The sensor S2 has the same configuration as Sl, but the distance P2 between the core 6-2 and the spacer 4-2 in the core part 2-2 is Pl.
It is different from Core part 2-1 of sensor °S1 and S2
．． 2-2 are connected by a connecting member 12, and move in a straight line with the center of the linear displacement X of the object to be detected. Also, the original signal Y2=K sin (ωt+φ2) is obtained from the quadratic A law of the sensor S2.However, when this phase shift amount φ2 is 2π, the linear displacement X is 1 of the core 6-2.
This corresponds to the pinch length P2.

Both sensors S1. The secondary side output signals Y, , Y2 of S2 are
By applying it to the phase difference detection circuits 37-1 and 67-2 shown in the figure, a periodic electrical output signal D having one cycle of mechanical linear displacement corresponding to each pinch length PlyP2 is generated.
1, D2 can be obtained.

In FIG. 4, the oscillator 62 has a reference sine signal of five times ωt.
and a phase difference detection circuit 67, which generates the cosine signal part ωt.
-1 is a circuit for measuring the phase shift φ, and 67-2 is a circuit for measuring φ2. The clock pulse CP oscillated from the chronograph oscillator 66 is counted by the counter 60. The counter 60U is modulo M, and its count value is applied to the input of a flip-flop 340) for dividing the frequency by 7 when the frequency Pc is exceeded. The pulse Pb output from the Q output of this flip-flop 64 is applied to the flip-flop processor 5, the pulse Pa output from the Q output is applied to the flip-flop processor 6, and the outputs of the connectors 65 and 66 are applied to the low-pass filters 21, 22 and the amplifier. 23.2
4, cosine signal preωt and sine signal sinωt
is obtained and input to the sensors Sl and S2. counter 6
M counts at 0 are these reference signal parts ωt, sin
This corresponds to a phase angle of 2π radians of ωt. That is,
The 2π-runt value of the counter 60 indicates the phase angle of the Fujian.

In the circuit 7-1, the output signal Y of the sensor S1 is applied to the comparator 26 via the amplifier 25, and the signal Y
A square wave signal corresponding to the positive/negative polarity of the comparator 26
is output from. In response to the rise of the output signal of the comparator 26, the rise detection circuit 28 outputs a pulse Ts, which loads the count value of the counter 60 into the register 61 in accordance with S. As a result, a digital value D1 corresponding to the phase shift φ is taken into the register 61.

The other circuit 67-2 has the same configuration as the circuit 67-1, and inputs the secondary output signal ¥2 of the sensor S2 to the comparator 69 via the amplifier 68, and controls the register 41 via the rising edge detection circuit 40. Then, the digital value D1 corresponding to the phase shift φ2 is taken into the register 41 from the counter 60. Incidentally, it is also possible to use only one phase difference detection circuit 7-1, provide only one register 61.41 corresponding to each sensor Sl, S2, and use the phase difference detection circuit in a time-division manner.

Both sensors S1. determined as above. Output signal of S21. D2 is supplied to the calculation COM (FIG. 1) as described above, and calculation is performed according to equation (3). However, when the phase difference detection circuit 67-1, 67-2 is configured as shown in FIG.
) is the formula. Of course, there is no problem even if it is N1\N2.

Incidentally, in the example of FIG. 2, if 1]2-P is a, it corresponds to D,2 =1J, -02. Here, φ
I-φ2. (That is, the phase value corresponding to L) +2) is the maximum of 1 straight 2π (that is, 1 period of IJ, -D2) is 1 straight of X MAX is Xhui, = P, ,! (P → engineering) ... (5) This equation (5) shows the maximum absolute detectable range when two sensors S1 and S2 are used.

For example, when P1=10mm, a=]mrn, XTVI
AX is rlloJ, and the absolute detection capability range of sensor 81 alone is P, (10mm)O) 11 times (
It can be seen that the abunlute detection range is expanded to a range of 110 dishes).

In order to further expand this Absolute 1 detectable range, the number of sensors may be further increased. For example, a third sensor S3 is further provided (with geometrical displacement P3),
P3\P1\P2) for one round] is outputted according to the linear displacement X.

By making the period of rD+D2J longer than the period of rD+D2J, it is possible to have the same state of ``D, -D2J'' based on rDl-D3J.

By the way, if the circumference jυLnCxk is simply calculated using the above equation (3) or (4), the setter S1. An error may occur due to the detection decomposition 1j ratio of S2-. this is,
Theoretically, it is a number that changes continuously with changes in r, D, -D 2 J beams, , I)2, but in reality rD
l-I]2'' is step-like, and Dl and D
This is because the second change step is also asynchronous. In order to eliminate the error caused by this, rD, -D in a predetermined range before and after the output D1 of the processor s1 is switched.
What is necessary is to add or subtract a predetermined numerical value to the value of 2J.

In the above description, the core portions 2-1, 2-2 are pushed down and the coil is kept stationary, but the reverse may be used.

In Figure 2, the mechanical displacement given to the first sensor s1 and the mechanical displacement given to the second sensor s2 are the same, but it is possible to The linear displacement to be detected may be applied to the sensors S1 and 82 with different transmission ratios. In that case, for example, the pinch of the cores 3-1 and 3-2 of the sensors s1 and s2 may be the same, the transmission ratio of the linear displacement to be detected to the sensor S1 may be 1, and the transmission ratio to the sensor S2 may be 2. . The displacement of the object to be detected is directly transmitted to one sensor S1, and the other sensor S2 is connected to a power source (this is a linear power source) that displaces at a predetermined ratio (for example, T7) in synchronization with the displacement of the object to be detected. )
may be given a displacement of Furthermore, it is not necessary that all of the plurality of sensors be linear sensors, and rotary sensors may be used. The twisted linear type sensor is not limited to the phase shift type as shown in Figure 2, but also has multiple cores as shown in the figure to obtain periodic analog DC voltage according to the linear position. A differential transformer-type hinger, or one that obtains a periodic output according to the linear position by counting the incremental pulses with a counter,
Any other linear processor may be used. Furthermore, based on the output of each sensor, the number of cycles of the output of a given sensor (
The arithmetic expression for determining the absolute address (corresponding to each core 6-1) is not limited to the one described above, but can be arbitrarily set based on mathematical analysis.

As explained above, according to the present invention, each is different. Multiple detections that generate an output/signal with one cycle of mechanical linear displacement in response to the linear displacement of the detection target; Since the ηIS is provided, it is possible to detect one cycle of the displacement of these detection parts. The output signal of a predetermined detection unit can be assigned an address over multiple cycles by calculation using the difference, and the combination of the address of this cycle and the output signal (within one cycle) of the detection unit can cover a wide range. It becomes possible to specify the absolute linear position. Moreover, the overall detection resolution is 1
Since it depends on the resolution of the output signal for the period, extremely high resolution can be achieved.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing one embodiment of the present invention, Fig. 2 is a sectional view specifically showing an example of the sensor portion used in the invention, and Fig. 3 is the primary and secondary coils of Fig. 2. FIG. 4 is a block diagram showing an example of a circuit for detecting a phase shift according to the amount of linear displacement included in the AC signal output from each sensor in FIG. 2. . SL, S2... Linear processor, COM... Arithmetic unit, 2-1, 2-2... Core section, 3-1.3-2...
Core, 5-1.5-2... Spacer, 4-1... Casing, 7.8, 9, 10... Primary coil, 11.
12, 13. 14... Secondary coil, 37-1, 37-
2...Phase difference detection circuit. Patent applicant Nisgy Co., Ltd. Agent Yoshihito Iizuka

Claims (1)

[Claims] J. A plurality of detection units that generate electrical output signals at a predetermined period corresponding to different amounts of mechanical displacement with respect to mechanical linear displacement of a detection target, and differences in the synchronization between each detection unit. and an arithmetic means for calculating the number of cycles from the origin of the detection target to the current position with respect to a predetermined one of the detection units, using the output/signal of each detection unit, and an integer part of the determined number of cycles. and an output signal of the predetermined detection section to specify the absolute position of the detection target. 2. The detection unit includes a phase-shift type sensor that generates an output that is a phase-shifted reference AC signal according to the linear position of the detection target, and a circuit that measures the phase shift between the output signal of this sensor and the reference AC signal. An absolute linear position detection device according to claim 1, comprising: 3. The phase shift type sensor includes a plurality of primary coils arranged at predetermined intervals in a linear displacement direction, a secondary coil provided corresponding to the primary coil, and the primary coil and a core portion including a plurality of cores provided in a direction of linear displacement relative to the secondary coil and provided at predetermined intervals in the direction of linear displacement; The secondary coil is individually excited by a reference AC signal, thereby causing the secondary coil to generate an output signal whose phase is shifted from the reference AC signal according to the linear position of the core portion with respect to the coil. The absolute linear position detection device according to item 2. 4. Each of the plurality of detection parts generates a periodic electrical output signal with each period having a different amount of mechanical displacement, and each of these detection parts has a common linear motion of the target (detection 1-1). The Absolute 1 linear position detection device according to claim 1, wherein transmission is performed at a transmission ratio of . 5. Each of the plurality of detection units has the same mechanical f'
It generates a periodic electrical output signal with one rotation of M and jυ], and the i-line motion of the detection target is transmitted to each of these detection units at different transmission ratios, and as a result, the detection target Absolute 1 according to claim 1, wherein an output signal corresponding to a total period of different mechanical displacements with respect to the linear displacement of the sensor is obtained from each detection section.
Linear position detection device.