CN102305590A - Curve displacement sensor system and applications thereof - Google Patents

Abstract

The invention discloses a curve displacement sensor system and applications thereof. The curve displacement sensor system comprises a movable sensor moving along with an object in curve motion, and a static sensor playing a role in reference as the moving signal of the movable sensor; the displacement is represented by high-frequency pulse numbers of the movable sensor and/or the static sensor. The curve displacement sensor system has the advantages of simple structure, convenient installation, low cost, high measurement accuracy and resolution ratio, no zero setting and the like.

Description

Curve displacement sensing system and uses thereof

The application is an application number: 201010255266.2, the applying date: 2010.08.10, title: the dividing an application of " curve displacement sensing system and uses thereof ".

Technical field:

The present invention relates to a kind of curve displacement sensor, specifically, relate to a kind of high-precision digital curve displacement sensor.

Background technology:

The displacement detecting technology is a constantly technology of development; Develop rapidly along with science and technology; In commercial production and scientific research process, the precision of displacement detecting, speed etc. are required also more and more higher, the digital non-contact detection of high precision displacement particularly.The research and the utilization that combine also to have expanded greatly traditional sensors of sensor and emerging technology.Displacement measurement is one of project the most basic in the measuring technique, and is very extensive in engineering application, has very important position.Therefore, the displacement transducer of seeking simple and practical, easy to operate, wide accommodation, good economy performance has important practical significance to promoting the commercial production development.

The curve displacement sensor that has high performance-price ratio in the market is very limited, and angular displacement commonly used and linear displacement transducer all can not directly detect as the high precision curve displacement.So high precision curve displacement sensing will obtain paying attention to and development in future.The fields such as closed-loop control of unit head when the curve displacement sensor mainly applies to accurate measurement and assembling, the Curve Machining (welding, cutting, engraving etc.) of some irregular materials and structure.Such sensor is compatible straight line and angle and measurement, and develop to some extent in the curvature context of detection, can be in fields such as commercial production, space flight navigation, new material and military military projects by extensive utilization.

The curve displacement high-acruracy survey is the difficult point in the mechanical value measuring, generally adopts following several method:

1. the indirect method of measurement

Calculate the terminal curve displacement through displacement measurement to driving mechanism.That driving mechanism generally has is electronic, drive and surge three kinds.The most common with electric driving mechanism, two motors can be realized the terminal plane curve movement through gearings such as gear screw mandrels, and three motors can be realized terminal three-dimensional space curve motion through gearings such as gear screw mandrels.Through installing photoelectric encoder on the motor additional or on gear train, installing the displacement detecting that the grating chi can be accomplished each degree of freedom additional, and finally be converted into the terminal curve displacement of system.Adopt this method, can't overcome influences such as gear train hysterisis error, gap error, and the resolution of photoelectric encoder or grating chi and precision have directly determined the curve displacement accuracy of detection.Know the terminal mobile message of system at many, and do not know under the actual condition of gear train situation that this method is not had a versatility.

2. the direct method of measurement

The direct method of measurement generally adopts roller to be fixed on riding on the measured object, adopts sensing technology to convert the curve top offset into simulating signal or digital signal through roller.Method is simple for this, but the terminal operating mode of many curve mobile systems does not allow to install roller, and the perhaps terminal unsettled roller that makes can't contact with object of reference, makes this method have bigger limitation.

Along with development of digital image, adopt imageing sensor and the displacement of image processing techniques detection curve more and more attracting researcher's concern.CCD image sensor (Charge Couple Device) be divided into one dimension with two dimension, the former is used for the detection of displacement, size, the latter is used for the transmission of planar graph, literal.The measurement of curve displacement in the industrial processes can utilize one dimension CCD device to realize.At first project on the CCD device, according to total number-of-pixels with by the number of pixels of image coverage, calculate tested length of curve again by the unknown length of curve of optical imagery method with measured object.The quantity of information that vision sensor provides is abundant, and adaptive faculty is strong, but cost is high, makes its application receive certain limitation.And under the stronger operating mode of light interference, when welding the displacement of diced system terminal curve as measuring, image processing algorithm is complicated, and message processing time is long, real-time is poor.

Summary of the invention

The curve displacement sensing system that the present invention provides that a kind of measurement range is big, simple in structure, easy for installation, cost is low, measuring accuracy and resolution are high, need not return to zero.

The technical solution adopted for the present invention to solve the technical problems is:

A kind of curve displacement sensing system; It is characterized in that: comprise the mobile dynamic sensor of object that moves with curve; Other has had the movable signal of pair dynamic sensor to make the quiet sensor device with reference to effect, levies the displacement size through the high-frequency impulse numerical table of dynamic sensor and/or quiet sensor.

Described curve displacement sensing system; The mobile dynamic sensor of testee that moves with curve is arranged; Other has a left side; The right side is synchronous motor at the uniform velocity; A left side; The sense of rotation of right at the uniform velocity synchronous motor is identical; A left side; Connect respectively on the output shaft of right at the uniform velocity synchronous motor and have the infrared light reflection action; And the reflective rod that rotates with motor output shaft; The Plane of rotation of reflective rod is vertical with motor output shaft; The motor output shaft axle center is the reflective excellent Plane of rotation center of circle; The Plane of rotation of two reflective rods has overlapped zone; This overlapping region is effective detection zone of movement of objects, and promptly the moving range of testee is in above-mentioned overlapping region; There have a quiet sensor to be fixed on to be left and right at the uniform velocity between the synchronous motor; Said dynamic sensor, quiet sensor are reflective single beam infrared photoelectric sensor.Dynamic sensor, quiet sensor are connected with comparer respectively; Comparer is connected with single-chip microcomputer; Single-chip microcomputer is given the counter module of FPGA through I/O mouth output control signal; Realize the switching of technology and latch function through the conversion of single-chip microcomputer mouth line high-low level; Latch returns single-chip microcomputer to data, and single-chip microcomputer is exported demonstration to the result through calculating.When under the operating mode that has high light to disturb, using, can adopt the position transducer of other kinds such as Hall element, eddy current sensor to replace reflective photoelectric sensor.Hall element, eddy current coil sensitive elements such as (eddy current probes) are installed on the curve track (track), and the same reflective photoelectric sensor in installation site replaces with field generator for magnetic or swirl plate with reflective rod, with the output of sensitive element as position signalling.

Described curve displacement sensing system; The mobile trailing type dynamic sensor of testee that moves with curve is arranged; Other has a left side; The right side is synchronous motor at the uniform velocity; A left side; Install first respectively on the output shaft of right at the uniform velocity synchronous motor; Second dynamic sensor; First; Second dynamic sensor is a photoemitter; A left side; Install first respectively on the shell of right at the uniform velocity synchronous motor; The second quiet sensor; First; The second quiet sensor is a photoelectric receiving device; The trailing type dynamic sensor is installed several light receiving elements in a circle 360 degree scopes, guarantee that testee all can receive first under any position; The light signal that second dynamic sensor sends; The installation site of first, second quiet sensor is for receiving the position of the light signal that second, first dynamic sensor sends respectively.

Described curve displacement sensing system; The mobile dynamic sensor of testee that moves with curve is arranged; Dynamic sensor is fixed on synchronous uniform speed electric motor's axle; Following motor synchronous at the uniform velocity rotates; Synchronous motor is fixed on the testee; Follow object and be synchronized with the movement, other has first, second quiet sensor to be fixed on testee curve displacement track both sides; Said dynamic sensor is the photoemission sensor, and first, second quiet sensor is a photoelectric receiving transducer, and the plane that the beam axis rotation that dynamic sensor sends forms is vertical with electrical axis.

Dynamic sensor, quiet sensor are connected with comparer respectively; Comparer is connected with single-chip microcomputer; Single-chip microcomputer is given the counter module of FPGA through I/O mouth output control signal; Realize the switching of technology and latch function through the conversion of single-chip microcomputer mouth line high-low level; Latch returns single-chip microcomputer to data, and single-chip microcomputer is exported demonstration to the result through calculating.

A kind of purposes of curve displacement sensing system; It is characterized in that: be used for the detection curve displacement or detect amount of curvature; When detecting amount of curvature; Through three points in the reflective excellent rotation sweep dynamic sensor moving process; Adopt two sections little fitting a straight line circular arcs, adopt the high-frequency impulse filling and combine trigonometric function operation to obtain radius-of-curvature and amount of curvature.

A kind of purposes of curve displacement sensor; It is characterized in that: through linear displacement transducer is installed on testee; With any one plane vertical with electrical axis is reference; Detect testee and this interplanar change in displacement; The track of testee in three dimensions can be confirmed through solid geometry calculating, the three-dimensional space curve displacement detecting can be realized.

The beneficial effect of high-precision digital curve displacement sensor of the present invention mainly shows:

1. simple in structure, easy to process, realize the digitizing non-contact detection.Cost is low, is beneficial to batch process.

2. measurement range is big.

3. except the high precision curve displacement detects, can realize that high precision curvature detects.Sensor simply transformed to realize the three-dimensional curve displacement detecting.

4. precision and resolution are high, keeping adopting the high-frequency impulse completion method under the stable prerequisite of motor speed, can obtain very high precision.

5. need not return to zero before measuring, make things convenient for testing process.

Description of drawings:

Fig. 1 is curve displacement sensor embodiment 1 a bulk junction composition of the present invention;

Fig. 2 is curve displacement sensor embodiment 1 a measuring principle diagrammatic top view 1 of the present invention;

Fig. 3 is curve displacement sensor embodiment 1 a measuring principle sequential chart 1 of the present invention;

Fig. 4 is curve displacement sensor embodiment 1 a measuring principle diagrammatic top view 2 of the present invention;

Fig. 5 is curve displacement sensor embodiment 2 bulk junction compositions of the present invention;

Fig. 6 is curve displacement sensor embodiment 2 measuring principle diagrammatic top view 1 of the present invention;

Fig. 7 is curve displacement sensor embodiment 2 measuring principle sequential charts 1 of the present invention;

Fig. 8 is curve displacement sensor embodiment 2 measuring principle diagrammatic top view 2 of the present invention;

Fig. 9 is curve displacement sensor embodiment 2 measuring principle sequential charts 2 of the present invention;

Figure 10 is curve displacement sensor embodiment 3 bulk junction compositions of the present invention;

Figure 11 is curve displacement sensor embodiment 3 measuring principle diagrammatic top view of the present invention;

Figure 12 is curve displacement sensor embodiment 3 measuring principle sequential charts of the present invention;

Figure 13 is that curve displacement sensor of the present invention adopts embodiment 1 to carry out curvature measuring principle vertical view;

Figure 14 is that curve displacement transducer curvature of the present invention detects ideal model figure;

Figure 15 is a S T188 infrared sensor interface circuit block diagram in the curve displacement sensor interface circuitry of the present invention;

Figure 16 is a curve displacement sensor interface circuitry block diagram of the present invention;

Figure 17 is sensor and a single-chip microcomputer connecting circuit in the curve displacement sensor interface circuitry of the present invention;

Figure 18 is single-chip microcomputer and a FPGA connecting circuit in the curve displacement sensor interface circuitry of the present invention;

Figure 19 is that FPGA counts and latch artificial circuit figure in the curve displacement sensor interface circuitry of the present invention;

Figure 20 is a FPGA counting simulation result in the curve displacement sensor interface circuitry of the present invention.

Embodiment

Below in conjunction with accompanying drawing the present invention is further described.

Embodiment 1 (being embodiment 1):

The mobile dynamic sensor 1 of testee that moves with curve is arranged; Other has a left side; The right side is synchronous motor 3 at the uniform velocity; 4 (is motor A; B); A left side; The sense of rotation of right at the uniform velocity synchronous motor is identical; A left side; Connect respectively on the output shaft of right at the uniform velocity synchronous motor and have the infrared light reflection action; And the reflective rod (being called aluminium bar or metal bar) 5 that rotates with motor output shaft; 6 (is aluminium bar A; B); The Plane of rotation of reflective rod is vertical with motor output shaft; The motor output shaft axle center is the reflective excellent Plane of rotation center of circle; The Plane of rotation of two reflective rods has overlapped zone; This overlapping region is effective detection zone of movement of objects, and promptly the moving range of testee is in above-mentioned overlapping region; Have a quiet sensor 2 be fixed on left and right at the uniform velocity synchronous motor 3, between 4; Said dynamic sensor 1, quiet sensor 2 are reflective single beam infrared photoelectric sensor.

When metal bar process reflective photoelectric sensor, the light that the interface circuit infrared transmitting tube of sensor sends is through reflection, and sensor receiving tube signal is through an exportable high level pulse.When metal bar during without reflective photoelectric sensor, the receiving end output low level.As shown in Figure 1, testee is gone up at orbit (track) and is moved, and dynamic sensor (reflective photoelectric sensor) is followed the testee motion, and quiet sensor (reflective photoelectric sensor) is fixed on the two synchronous motor axle center lines.Add man-hour in order to make motor when rotation steady, aluminium bar adopts symmetric mode to be fixed on the motor shaft.

(1) when the testee moving direction when the quiet sensor

As shown in Figure 2, promptly testee moves to M3 until this process of axial connecting line by M0.This sensor is applicable to the occasion that testee slowly moves, and is specially adapted to the object stepping and moves occasion.If mobile object is stepping, initial position starts synchronous motor earlier and drives aluminium bar at M0 before measurement, and aluminium bar has two pulse signal outputs through dynamic sensor and quiet sensor.Owing to two motors are arranged with the moving two aluminium bars rotation of speed belt, and make two aluminium bars have the time difference, then can note two groups of signals, as shown in Figure 3 through quiet sensor.

Before object did not move, A, B two motors 3,4 drove aluminium bars and rotate, and when aluminium bar process dynamic sensor and quiet sensor, produce pulse signal, are designated as the T0 pulse signal in the moment.If the dynamic sensor and the starting phase angle between the quiet sensor that are reference with two rotating shaft hearts can be designated as α 0, β 0 (see figure 2) respectively.Start the high-frequency impulse counting when crossing dynamic sensor, stop counting during quiet sensor.Fill high-frequency impulse N in the one-period if A, B motor rotate, the N value is two high-frequency impulse numbers that continuous quiet sensor is interpulse.Then note high-frequency impulse number NA0 and NB0 constantly by T0 and in the cycle ratio of overall pulse number N can confirm between object initial position and the quiet sensor phase angle [alpha] 0, β 0 with respect to two electrical axis A, B.In like manner according to record data NA1, NB1, NA2, NB2 ... Can obtain moment dynamic sensors such as T1, T2 is phase angle [alpha] 1, β 1, α 2, β 2 between reference and the quiet sensor for two axle center ...

Because A, B two motor positions confirm that its two motors distance is made as L (known), can try to achieve M0 and quiet sensor angle 0, the β 0 with respect to A, B again, has so just confirmed the initial position M0 of object.

${\mathrm{\α}}_0=\frac{N_{A0}}{N}*360---\left(1\right)$

${\mathrm{\β}}_0=\frac{N_{B0}}{N}*360---\left(2\right)$

${\mathrm{<figure-callout\; id="0"\; label="AM"\; filenames="110728150026.png,110728150048.png"\; state="\{\{state\}\}">AM</figure-callout>}}_0=\frac{\sin {\mathrm{\&alpha;}}_0}{\sin ({\mathrm{\&alpha;}}_0+{\mathrm{\&beta;}}_0)}*L=\frac{\sin (\frac{N_{a0}}{N}*360)}{\sin (\frac{N_{a0}+N_{b0}}{N}*360)}*L---\left(3\right)$

When testee is subjected to displacement, dynamic sensor also is synchronized with the movement, and moves to the M1 position like M0, and quiet sensor output this moment impulse phase still and do not become, and dynamic sensor output impulse phase has changed, and α 0, β 0 have also become α 1, β 1.

${\mathrm{\&alpha;}}_1=\frac{N_{A1}}{N}*360---\left(4\right)$

${\mathrm{\&beta;}}_1=\frac{N_{B1}}{N}*360---\left(5\right)$

${\mathrm{<figure-callout\; id="1"\; label="AM"\; filenames="110728145955.png,110728145958.png"\; state="\{\{state\}\}">AM</figure-callout>}}_1=\frac{\sin {\mathrm{\&alpha;}}_1}{\sin ({\mathrm{\&alpha;}}_1+{\mathrm{\&beta;}}_1)}*L---\left(6\right)$

So just can obtain dynamic sensor and move distance A M0, the AM1 of front and back two positions to A.

Because AM0, AM1 and their angle (α 0-α 1) can know, the displacement M0M1 before and after the object can try to achieve:

$M_0{\mathrm{<figure-callout\; id="1"\; label="M"\; filenames="110728145955.png,110728145958.png"\; state="\{\{state\}\}">M</figure-callout>}}_1=\sqrt{[{{\mathrm{<figure-callout\; id="0"\; label="AM"\; filenames="110728150026.png,110728150048.png"\; state="\{\{state\}\}">AM</figure-callout>}}_0}^2+{{\mathrm{<figure-callout\; id="1"\; label="AM"\; filenames="110728145955.png,110728145958.png"\; state="\{\{state\}\}">AM</figure-callout>}}_1}^2-2\cos ({\mathrm{\&alpha;}}_0-{\mathrm{\&alpha;}}_1){\mathrm{<figure-callout\; id="0"\; label="AM"\; filenames="110728150026.png,110728150048.png"\; state="\{\{state\}\}">AM</figure-callout>}}_0{\mathrm{AM}}_1]}---\left(7\right)$

Adopt said method can obtain the linear movement measuring general formula:

${\mathrm{\&alpha;}}_n=\frac{N_{\mathrm{An}}}{N}*360---\left(8\right)$

${\mathrm{\&beta;}}_n=\frac{N_{\mathrm{Bn}}}{N}*360---\left(9\right)$

${\mathrm{AM}}_n=\frac{\sin {\mathrm{\&alpha;}}_n}{\sin ({\mathrm{\&alpha;}}_n+{\mathrm{\&beta;}}_n)}*L---\left(10\right)$

${\mathrm{AM}}_{n-1}=\frac{\sin {\mathrm{\&alpha;}}_{n-1}}{\sin ({\mathrm{\&alpha;}}_{n-1}+{\mathrm{\&beta;}}_{n-1})}*L---\left(11\right)$

$M_{n-1}{M}_n=\sqrt{[{{\mathrm{AM}}_{n-1}}^2+{{\mathrm{AM}}_n}^2-2\cos ({\mathrm{\&alpha;}}_{n-1}-{\mathrm{\&alpha;}}_n){\mathrm{AM}}_{n-1}{\mathrm{AM}}_n]}---\left(12\right)$

Through above method the straight-line segment addition that obtains can be obtained curve displacement.When movement of objects speed was very slow, straight-line segment is section very, but because there is the time difference in the scanned sensor of two motors, so there is certain error in curve displacement calculating.The testee translational speed is slow more, and the motor rotational speed is fast more, and then error is more little.When testee is stepping when moving, measurement can obtain very high resolution and precision.

More than calculating draws under hypothesis A, the even and of the same size situation of B two motor speeds, and in the practical operation, A, B two motor speeds can not be identical, and asking α this moment _nAnd β _nThe time, two motors are counted N at the pairing high-frequency impulse that rotates a circle and can be adjusted according to actual conditions.Concrete when calculating N, can calculate that the high-frequency impulse number draws between two adjacent quiet sensors through interface circuit.

(2) when testee moving direction during away from quiet sensor

As shown in Figure 4, both be that object begins from crossing two rotating shaft lines, move to Mn until this process of farther place through Mn-1.Formula 8,9 will be no longer suitable this moment.When dynamic sensor during through two electrical axis lines; The situation that must exist aluminium bar not pass through dynamic sensor through twice quiet sensor continuously; Therefore can judge through interface circuit; When the dynamic sensor pulse not occurring when continuous two the quiet sensor pulses of appearance of interface circuit discovery; Can do suitably to revise to formula 8,9 through the simple geometry analysis, but 12 right being suitable for of formula.

Embodiment 2 (being embodiment 2):

The mobile trailing type dynamic sensor 7 (being dynamic sensor M) of testee that moves with curve is arranged; Other has a left side; The right side is synchronous motor 8 at the uniform velocity; 9 (is motor A; B); A left side; Install first respectively on the output shaft of right at the uniform velocity synchronous motor; Second dynamic sensor 10; 11 (is dynamic sensor A; B); First; Second dynamic sensor is a photoemitter; A left side; Install first respectively on the shell of right at the uniform velocity synchronous motor; The second quiet sensor 12; 13 (is quiet sensors A; B); First; The second quiet sensor is a photoelectric receiving device; The trailing type dynamic sensor is installed several light receiving elements in a circle 360 degree scopes, guarantee that testee all can receive first under any position; The light signal that second dynamic sensor sends; The installation site of first, second quiet sensor is for receiving the position of the light signal that second, first dynamic sensor sends respectively.

As shown in Figure 5, dynamic sensor M is a photelectric receiver, the fixing and same moved further with testee.Dynamic sensor A, B are photoemitter, are fixedly connected with motor A, B axle respectively, synchronously rotation.Quiet sensors A, B are photoelectric receiving device, are fixedly connected transfixion with motor housing.When dynamic sensor M installs; Several light receiving elements are installed (after multiple collector spare signal handles through modulate circuits such as comparers in a circle 360 degree scopes; Through or door connect), guarantee that testee all can receive the light signal that dynamic sensor A and B send under any pose.Quiet sensors A, B should be able to guarantee to receive respectively the light signal that dynamic sensor B, A send when installing.

Two dynamic sensor rotations of driven by motor, dynamic sensor A transmits, and M and B successively receive this signal.In like manner B transmits, and M, A also successively receive signal.

(1) when testee during near A, B electrical axis line

As shown in Figure 6.When testee does not move, start two synchronous motors earlier, but measurement range can expand the common factor of two photoelectric sensor induction regions to.The signal that quiet sensors A receives is that dynamic sensor B sends, and what quiet sensor B accepted is that dynamic sensor A sends, and M accepts the signal of dynamic sensor A, two emissions of B.When M moved, the phase place of M acknowledge(ment) signal and quiet sensors A, B acknowledge(ment) signal can change, and phase differential has embodied the variation of M displacement.Sequential chart as shown in Figure 7.If AB two electrical axis lines distances is L, the motor B high-frequency impulse quantity that rotates a circle is N _B, the motor A high-frequency impulse number that rotates a circle is N _ACan get:

${\mathrm{\&alpha;}}_0=\frac{N_{B0}}{N_B}*360---\left(13\right)$

${\mathrm{\&beta;}}_0=\frac{N_{A0}}{N_A}*360---\left(14\right)$

${\mathrm{<figure-callout\; id="0"\; label="AM"\; filenames="110728150026.png,110728150048.png"\; state="\{\{state\}\}">AM</figure-callout>}}_0=\frac{\sin {\mathrm{\&alpha;}}_0}{\sin ({\mathrm{\&alpha;}}_0+{\mathrm{\&beta;}}_0)}*L---\left(15\right)$

${\mathrm{\&alpha;}}_1=\frac{N_{B1}}{N_B}*360---\left(16\right)$

${\mathrm{\&beta;}}_1=\frac{N_{A1}}{N_A}*360---\left(17\right)$

${\mathrm{<figure-callout\; id="1"\; label="AM"\; filenames="110728145955.png,110728145958.png"\; state="\{\{state\}\}">AM</figure-callout>}}_1=\frac{\sin {\mathrm{\&alpha;}}_1}{\sin ({\mathrm{\&alpha;}}_1+{\mathrm{\&beta;}}_1)}*L---\left(18\right)$

$M_0{\mathrm{<figure-callout\; id="1"\; label="M"\; filenames="110728145955.png,110728145958.png"\; state="\{\{state\}\}">M</figure-callout>}}_1=\sqrt{[{{\mathrm{<figure-callout\; id="0"\; label="AM"\; filenames="110728150026.png,110728150048.png"\; state="\{\{state\}\}">AM</figure-callout>}}_0}^2+{{\mathrm{<figure-callout\; id="1"\; label="AM"\; filenames="110728145955.png,110728145958.png"\; state="\{\{state\}\}">AM</figure-callout>}}_1}^2-2\cos ({\mathrm{\&alpha;}}_0-{\mathrm{\&alpha;}}_1){\mathrm{<figure-callout\; id="1"\; label="AM"\; filenames="110728145955.png,110728145958.png"\; state="\{\{state\}\}">AM</figure-callout>}}_1{\mathrm{AM}}_2]}---\left(19\right)$

${\mathrm{AM}}_n=\frac{\sin {\mathrm{\&alpha;}}_n}{\sin ({\mathrm{\&alpha;}}_n+{\mathrm{\&beta;}}_n)}*L---\left(20\right)$

${\mathrm{AM}}_{n-1}=\frac{\sin {\mathrm{\&alpha;}}_{n-1}}{\sin ({\mathrm{\&alpha;}}_{n-1}+{\mathrm{\&beta;}}_{n-1})}*L---\left(21\right)$

$M_{n-1}{M}_n=\sqrt{[{{\mathrm{AM}}_{n-1}}^2+{{\mathrm{AM}}_n}^2-2\cos ({\mathrm{\&alpha;}}_{n-1}-{\mathrm{\&alpha;}}_n){\mathrm{AM}}_{n-1}{\mathrm{AM}}_n]}---\left(22\right)$

Through above method the straight-line segment addition that obtains can be obtained curve displacement.When movement of objects speed was very slow, straight-line segment is section very, but because there is the time difference in the scanned sensor of two motors, so there is certain error in curve displacement calculating.The testee translational speed is slow more, and the motor rotational speed is fast more, and then error is more little.When testee is stepping when moving, measurement can obtain very high resolution and precision.

(2) when testee during away from A, B electrical axis line

The measuring principle sketch as shown in Figure 8, sequential chart is as shown in Figure 9. Formula 16,17 will be no longer suitable this moment.As dynamic sensor M during through two electrical axis lines; Must exist quiet sensors A continuously two pulses to occur and the situation of pulse does not appear in dynamic sensor M; Perhaps quiet sensor B continuously two pulses occur and the situation of pulse does not appear in dynamic sensor M; Therefore can judge through interface circuit; When the pulse of dynamic sensor M not occurring when continuous two the quiet sensor pulses of appearance of interface circuit discovery, can be through the simple geometry analysis to α _nAnd β _nDo suitably to revise, but 22 right being suitable for of formula.

Embodiment 3 (being embodiment 3):

The mobile dynamic sensor 14 (being dynamic sensor M) of testee that moves with curve is arranged; Dynamic sensor 14 is fixed on 15 of the synchronous uniform speed electric motors; Following motor synchronous at the uniform velocity rotates; Synchronous motor is fixed on the testee 16; Follow object and be synchronized with the movement, other has first, second quiet sensor 17,18 (being quiet sensors A, B) to be fixed on testee curve displacement track both sides; Said dynamic sensor is the photoemission sensor, and first, second quiet sensor is a photoelectric receiving transducer, and the plane that the beam axis rotation that dynamic sensor sends forms is vertical with electrical axis.

Dynamic sensor M is fixed on the synchronous motor shaft among the figure, follows motor synchronous and at the uniform velocity rotates.Synchronous motor is fixed on the testee, follows object and is synchronized with the movement.Quiet sensors A and B are fixed on curve displacement track (track) both sides.Used motor is a small synchronous motor, and also available rotating speed other motor uniformly replaces.Light source (photelectric receiver) also can adopt the Laser emission receiving trap.

Measuring principle as shown in figure 11.The measuring principle sequential chart as shown in figure 12.When testee moves continuously, variation continuously will take place to the scan period of 2 of A, B in the sensor of rotation continuously on testee.Can obtain:

${\mathrm{\&alpha;}}_0=(\frac{N_{A0}}{N}-1)*360---\left(23\right)$

${\mathrm{\&beta;}}_0=(1-\frac{N_{B0}}{N})*360---\left(24\right)$

$\&angle;{\mathrm{BM}}_{0}A=\frac{N_0}{N}*360---\left(25\right)$

Wherein N is the high-frequency impulse number of filling in the dynamic sensor M revolution week age.At triangle AM ₀Among the B, ∠ BM ₀A can ask, and when therefore using this scheme, must guarantee AM0, BM0, AB, ∠ M ₀BA, ∠ M ₀Any two values among the AB are known, then triangle AM ₀All angles and Bian Douke obtain among the B.And because ∠ BM ₁A=∠ BM ₀A+ α ₀+ β ₀, and ∠ BM ₁A can be tried to achieve by interface circuit automatically, therefore in actual measurement, only needs calculation of alpha ₀And β ₀In an amount get final product.Suppose α ₀Calculate, then at triangle AM ₀M ₁In, AM0 and α ₀Known, AM1 can be at triangle AM ₁Try to achieve among the B (because at triangle AM ₁Among the B, AB is known, ∠ M ₁AB=∠ M ₀AB-α ₀, ∠ M ₁BA=∠ M ₀BA-β ₀, then AM1 can get), M then ₀M ₁Can in the hope of.Through the simple geometric analysis M that can be moved at every turn _nM _N+1, addition promptly gets curve displacement.

4, curvature measurement embodiment

Curvature is the amount of expression curved degree.The curvature of plane curve is exactly to be directed against the rotation rate of the tangent directional angle of certain point on the curve to arc length, defines through differential, shows the degree of curve off-straight.Curvature is big more, and the degree of crook of expression curve is big more.K=lim| Δ α/Δ s|, when Δ s trended towards 0, definition K was exactly a curvature.

Three kinds of schemes that more than provide all can be used for realizing curvature measurement.Be that example explanation curvature detects principle with scheme 1 below.Detection is overlooked schematic diagram as shown in figure 13.With M0, M1, M2 is example, supposes at these 3 o'clock on a circular arc, because each the detection apart from very little; Can be approximated to be two segment straight lines; The focus of two straight line perpendicular bisectors is the center of circle of this circular arc then, and M1O1 is exactly a radius of curvature R, so just can be in the hope of the curvature of M1 position.Figure 14 is ideal model figure.

Utilize formula in the scheme one, ${\mathrm{<figure-callout\; id="0"\; label="AM"\; filenames="110728150026.png,110728150048.png"\; state="\{\{state\}\}">AM</figure-callout>}}_0=\frac{\sin {\mathrm{\&alpha;}}_0}{\sin ({\mathrm{\&alpha;}}_0+{\mathrm{\&beta;}}_0)}*L=\frac{\sin (\frac{N_{a0}}{N}*360)}{\sin (\frac{N_{a0}+N_{b0}}{N}*360)}*L,$ Make A (0,0), M ₀Coordinate is (AM ₀* cos α ₀, AM ₀* sin α ₀), in like manner obtain M ₁, M ₂On the position coordinate.

${\mathrm{<figure-callout\; id="1"\; label="AM"\; filenames="110728145955.png,110728145958.png"\; state="\{\{state\}\}">AM</figure-callout>}}_1=\frac{\sin {\mathrm{\&alpha;}}_1}{\sin ({\mathrm{\&alpha;}}_1+{\mathrm{\&beta;}}_1)}*L---\left(26\right)$

${\mathrm{<figure-callout\; id="2"\; label="AM"\; filenames="110728145955.png,110728150008.png"\; state="\{\{state\}\}">AM</figure-callout>}}_2=\frac{\sin {\mathrm{\&alpha;}}_2}{\sin ({\mathrm{\&alpha;}}_2+{\mathrm{\&beta;}}_2)}*L---\left(27\right)$

M1(AM1*cosα ₁，AM ₁*sinα ₁) (28)

M2(AM ₂*cosα ₂，AM ₂*sinα ₂) (29)

If (X0, Y0), (X1, Y1), (X2, Y2), (X, Y), radius-of-curvature is R to O1 to M2 to M1 to M0.Computing formula is following:

$\sqrt{{(X-X_0)}^2+{(Y-Y_0)}^2}=R---\left(30\right)$

$\sqrt{{(X-X_1)}^2+{(Y-Y_1)}^2}=R---\left(31\right)$

$\sqrt{{(X-X_2)}^2+{(Y-Y_2)}^2}=R---\left(32\right)$

Can get through calculating: O ₁Coordinate

$X=\frac{(y_0-y_1){(x_2-x_0)}^2+{(y_0-y_1)}^2\left(\frac{x_2-x_0}{x_1-x_0}\right)y_1-(y_0-y_1)(y_0-y_2)y_2}{(y_0-y_1)(x_2-x_0)-(y_0-y_2)(x_1-x_0)}-\frac{y_0-{\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="110728145955.png,110728145958.png"\; state="\{\{state\}\}">y</figure-callout>}}_1}{2(x_1-x_0)}{\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="110728145955.png,110728145958.png"\; state="\{\{state\}\}">y</figure-callout>}}_1+\frac{x_0+x_2}{2}---\left(33\right)$

$Y=\frac{(x_1-x_0){(x_2-x_0)}^2+(y_0-y_1)(x_2-x_0)y_1-(x_1-x_0)(y_0-y_2){\mathrm{<figure-callout\; id="2"\; label="y"\; filenames="110728145955.png,110728150008.png"\; state="\{\{state\}\}">y</figure-callout>}}_2}{2[(y_0-y_1)(x_2-x_0)-(y_0-y_2)(x_1-x_0)]}+y_0---\left(34\right)$

$R=\sqrt{{[X-x_0]}^2+{[Y-y_0]}^2}$ That is:

$R=\sqrt{{[\frac{(y_0-y_1){(x_2-x_0)}^2+{(y_0-y_1)}^2\left(\frac{x_2-x_0}{x_1-x_0}\right)y_1-(y_0-y_1)(y_0-y_2)y_2}{(y_0-y_1)(x_2-x_0)-(y_0-y_2)(x_1-x_0)}-\frac{y_0-{\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="110728145955.png,110728145958.png"\; state="\{\{state\}\}">y</figure-callout>}}_1}{2(x_1-x_0)}{\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="110728145955.png,110728145958.png"\; state="\{\{state\}\}">y</figure-callout>}}_1+\frac{x_2-x_0}{2}]}^2+{\left[\frac{(x_1-x_0){(x_2-x_0)}^2+(y_0-y_1)(x_2-x_0)y_1-(x_1-x_0)(y_0-y_2){\mathrm{<figure-callout\; id="2"\; label="y"\; filenames="110728145955.png,110728150008.png"\; state="\{\{state\}\}">y</figure-callout>}}_2}{2[(y_0-y_1)(x_2-x_0)-(y_0-y_2)(x_1-x_0)]}\right]}^2---\left(35\right)}$

5, novel curve displacement sensor interface circuitry design

The curve displacement sensor of three kinds of schemes has similarity in interface circuit design.Be the example explanation with scheme 1 below.

(1) hardware circuit design

Select for use ST188 one reflection infrared sensor as dynamic sensor and quiet sensor, its interface circuit as shown in figure 15, VCC selects for use+5V; GND ground connection, R1 selects (500～1000) Ω, and R2 selects 20K Ω; OUT is a signal output part, exports pulse behind the OUT termination comparer LM339.

The interface circuit block diagram makes full use of singlechip technology and EDA technology advantage separately as shown in figure 16, and hardware circuit adopts the form of FPGA (EP1K30TC144-3) assistant SCM (AT89C51).Sensors A, B signal are after LM339 handles; Input singlechip interruption mouth; Single-chip microcomputer P1.0, P1.1 mouth output control signal is given the counter module of FPGA, when P1.0 or P1.1 mouth output high level hour counter A or B begin numeration, stops counting during low level and latchs.Latch returns single-chip microcomputer to data, and single-chip microcomputer is exported demonstration to the result through calculating.

Sensor and interface microcontroller circuit as shown in figure 17, single-chip microcomputer and FPGA interface circuit are chosen con3 (P43,44 of FPGA as shown in figure 18; 46,47,48,49; 51,59,60,62; 63,64), DATA (P109,110,111; 112,113,114,116; 120,121,122) send remember the high-frequency impulse number.P64, P65 and P109, P110 comes connection control signal.

(2) software design

Single-chip microcomputer detects dynamic sensor earlier and interrupts, and will accomplish following action then: control counter A counting detects quiet sensor then and interrupts; Stop counter A counting, FPGA latchs this and counts A simultaneously, send single-chip microcomputer; After clear 0; Detect dynamic sensor again and interrupt, beginning counter B counting detected quiet sensor more afterwards and interrupted; Stop counter B counting; FPGA latchs this and counts B simultaneously, send single-chip microcomputer, clear 0 back circulation.

Used a lot of calculating in the whole procedure, comprised exponential function, factorial function, sin function, cos function, open radical sign function etc.Employing single-chip microcomputer c Programming with Pascal Language is more convenient in concrete the realization, also will consider the hybrid programming of single-chip microcomputer simultaneously.Be writing of several word programs necessary in the calculation procedure below:

Value after calculate finishing is sent into the display buffer, and what system adopted is the segment encode delivery outlets of 8 74LS164 as 8 LED, so result data is divided into 8 segment datas, through calculations of offset, tables look-up and calls side-play amount and be presented on 8 sections LED.The curve displacement size can be shown, and the dynamic change of curve displacement can be shown in real time.

In the FPGA design, use the 74163 and 74373 Puzzle lock deposit systems of forming.Two 74163 cascade circuit figure and simulation result are shown in Figure 18 and 19.For improving accuracy of detection, need to improve the high-frequency impulse frequency, can realize the high-frequency impulse counting this moment through continuous expansion counter and latch.

6, the three-dimensional space curve displacement detects

Three kinds of schemes that the present invention proposes are only applicable to the plane curve displacement detecting, can confirm the changes in coordinates of object in two dimensional surface.But the scheme that the present invention proposes can be extended to three-dimensional curve displacement detecting field easily.Only need on testee, to install linear displacement transducer (like laser sensor, ultrasonic sensor etc.); With any one plane vertical with electrical axis is reference; Detect testee and this interplanar change in displacement; Can confirm that object is in three-dimensional changes in coordinates; Calculate through solid geometry, can realize the three-dimensional space curve displacement detecting.

7, sensor precision and accuracy analysis

For linear movement pick-up, precision of measurement, accuracy and resolution are most important technical indicators.Precision of measurement is meant under the same terms, to measured repeatedly repeated measurement, the unanimity between the measured value (meeting) degree of carrying out.From the angle of measuring error, what precision reflected is the stochastic error of measured value.In native system, precision of measurement depends primarily on the degree of uniformity of synchronous rotational speed.

The rotating speed of the synchronous motor that is adopted in the experiment is 110r/min (1.83r/s), and the high-frequency impulse frequency that adopts active crystal oscillator to provide is 20MHz.Then motor revolution high-frequency impulse that each week is remembered is counted N=(60/110)/[1/ (20*10 ⁶)]=10909090.9.Recognizable in theory minimum angles is 0.000033 °.Suppose that testee is nearer from two motor shafts.If AM=0.1m, then the displacement that possibly distinguish in theory is tan0.000033 ° * 0.1=0.000000057m=5.7 * 10 ^-8M this shows, the resolution of this sensor is very high.

Accuracy of measurement is meant the degree of closeness between measured value and the true value.The method of digital interpolative that adopts this curve displacement sensor realizes that curve displacement measures, and accuracy of measurement depends on difference frequency, object of which movement speed slowly, measure under higher, the uniform prerequisite of motor speed of filler pulse frequency and have higher accuracy.

8, sensor strengths and weaknesses analysis and improvement

Advantage: (1) measurement range is big; (2) simple in structure, easy for installation, cost is low; (3) measuring accuracy and resolution are high; (4) need not return to zero before the measurement; (5) do not need to add in addition direction judgment circuit, through software directly declare to; (6) development potentiality is big, can expand.

Shortcoming:

(1) degree of uniformity of motor speed is one of principal element of decision sensor accuracy.The motor of selecting for use is a synchronous motor, mainly is because rotating speed can substantially constant during load variations, under the situation of material such as sensor displacement, reflection rod or structural change, need not carry out speed governing; But synchronous motor has bigger electromagnetism pulsation to cause speed ripple, and is influential to precision; Can further select rotating speed small and special electric machine more uniformly for use.

(2) to be mainly used in measurand with scheme 2 be the occasion that stepping is moved for scheme 1.In scheme one, measurand could move next step after whenever making a move and need stopping to wait for all scanned quiet, the dynamic sensor of two aluminium bars.In scheme two, measurand could move next step after whenever making a move and need stopping to wait for scanned quiet, the dynamic sensor of two dynamic sensors (infrared transmitting tube).Though the resolution of sensor is very high, can detect no matter how little the step distance of testee is in theory.But the use field that requires measurand obviously to limit sensor with the step-by-step system operation; In practical application; Scheme 1 and 2 sensors that propose can directly apply to the object that slowly moves; And do not require that the object stepping moves; The error of bringing thus is inevitable; But movement of objects speed is slow more, and error is more little.

(3) computing work connects bigger in the system interface circuit.As adopt single-chip microcomputer will accomplish relatively more complicated calculating such as comparison trigonometric function, can bring bigger electrical error to detection.In improving from now on, can accomplish complex calculation to improve system accuracy through selecting high-grade controllers such as DSP for use.

Claims (4)

1. curve displacement sensing system; It is characterized in that: the mobile dynamic sensor of testee that moves with curve is arranged; Dynamic sensor is fixed on synchronous uniform speed electric motor's axle; Following motor synchronous at the uniform velocity rotates; Synchronous motor is fixed on the testee; Follow object and be synchronized with the movement, other has first, second quiet sensor to be fixed on testee curve displacement track both sides; Said dynamic sensor is the photoemission sensor, and first, second quiet sensor is a photoelectric receiving transducer, and the plane that the beam axis rotation that dynamic sensor sends forms is vertical with electrical axis.

2. curve displacement sensing system according to claim 1; It is characterized in that: dynamic sensor, quiet sensor are connected with comparer respectively; Comparer is connected with single-chip microcomputer; Single-chip microcomputer is given the counter module of FPGA through I/O mouth output control signal; Realize the switching of technology and latch function through the conversion of single-chip microcomputer mouth line high-low level; Latch returns single-chip microcomputer to data, and single-chip microcomputer is exported demonstration to the result through calculating.

3. the purposes of the described curve displacement sensing system of claim 1; It is characterized in that: be used for the detection curve displacement or detect amount of curvature; When detecting amount of curvature; Through three points in the reflective excellent rotation sweep dynamic sensor moving process; Adopt two sections little fitting a straight line circular arcs, adopt the high-frequency impulse filling and combine trigonometric function operation to obtain radius-of-curvature and amount of curvature.

4. the purposes of the described curve displacement sensor of claim 1; It is characterized in that: through linear displacement transducer is installed on testee; With any one plane vertical with electrical axis is reference; Detect testee and this interplanar change in displacement; The track of testee in three dimensions can be confirmed through solid geometry calculating, the three-dimensional space curve displacement detecting can be realized.

Images