CN1884979A - Motion parameter measuring instrument - Google Patents

Abstract

The invention relates to a motion parameter measuring instrument for measuring motion parameters. The grating and the grating reading head are respectively fixed on an object which moves relatively, the grating reading head outputs an electric signal which is read from the grating and is related to the motion amount, the electric signal is converted into a digital signal through a data acquisition system, and a relationship curve between the motion amount and time is obtained through a data processing system. The invention adopts various gratings to calibrate the motion parameter sensor, and carries out field measurement on the linear motion amount and the angular motion amount of equipment such as a rotary table, a simulation table, a swing table, an angular vibration table, a low-frequency linear vibration table and the like; obtaining displacement, speed, acceleration or angular displacement, angular speed and angular acceleration measurement values at any moment in the measurement process; and the dynamic rotation quantity and the rotation speed fluctuation rate can be measured. The invention has the characteristics of high resolution of measured values, high time resolution of the measured values, capability of directly tracing the motion amount to time, length or angle and the like, and is suitable for measuring and calibrating the static or dynamic linear motion amount and the angular motion amount.

Description

Motion parameter measurer

Technical field

The present invention relates to a kind of motion parameter measurer of measuring kinematic parameter.

Background technology

Kinematic parameter can be divided into line motion and angular motion parameter two classes.The sensor of measuring kinematic parameter is of a great variety, general displacement transducer, speed pickup, the accelerometer measures line kinematic parameter of adopting adopts angular displacement sensor, gyro, speed probe, angular accelerometer and all kinds of systematic survey angular motion parameter of being made up of inertial sensor.

The kinematic parameter sensor needs calibration before measurement, adopt line vibration standard and angular oscillation standard that the sensor is calibrated.The source tracing method of kinematic parameter mainly is divided into two kinds in the calibration, and a kind of is absolute method, with laser interferance method kinematic parameter is traceable to time, length or angular metric, and accuracy is higher; Another kind is a relative method, measures the motion value with the standard transducer through calibration, and its advantage is that cost is low, method is simple, but accuracy is lower.Concrete grammar can be with reference to " measuring (Measurement) 2000 28 volumes " article " laser interferance method vibrates with shock measurement and traces to the source " (H.-J.v.Martens, A.T  ubner, W.Wabinski, A.Link, H.-J.Schlaak, " Traceability of vibration and shock measurements bylaser interferometry ", Measurement, 28 (2000), pp.3-20.).Laser interferometer is made up of laser instrument, optical system, photo-translating system and signal processing system etc.The ultimate principle that laser interferance method carries out movement parameter measurement is: be offset from the phase place and the frequency of its phase place of surface of moving object laser light reflected and frequency and incident light, by detecting this offset value, can obtain corresponding kinematic parameter.The advantage that adopts laser interferance method to carry out movement parameter measurement be accuracy height, frequency response range wide, with the measured target noncontact; Shortcoming is that system complex, cost are higher, and when tested surface of moving object was undesirable, signal to noise ratio (S/N ratio) was low.

In engineering was used, a large amount of line shaking tables, turntable, angle vibration table, inertia test need be carried out the field performance test with equipment such as simulation table and tilters.Present method is to adopt all kinds of kinematic parameter sensors to measure, and accuracy of measurement and resolution are lower, Hz-KHz is narrow, can not satisfy the demand.

The measurement of steady-state speed there has been the method for a lot of maturations, but also seldom, tech-generator method, multiple tooth and multiple labeling close classification etc. have been arranged at present the measuring method of dynamic rotating speed and speed fluctuation rate.The tech-generator method is utilized electromagnetic induction principle, and its output voltage is directly proportional with rotating speed, and its shortcoming is to carry out that the kinetic measurement Hz-KHz is narrow, accuracy is low.Multiple tooth and multiple labeling close classification generally is made up of fluted disc or mark dish, capacitive transducer or photoelectric sensor and tachometer circuit etc., they can change tachometric survey into a rotation period by measurement complete cycle and carry out repeatedly tachometric survey, but its segmentation number is limited, cause the temporal resolution of transient speed low, can not satisfy the kinetic measurement needs.

Summary of the invention

The purpose of this invention is to provide the high motion parameter measurer of a kind of accuracy of measurement.Technical solution of the present invention is, grating and grating reading head are separately fixed on the object of relative motion, the electric signal relevant that grating reading head output is read from grating with amount of exercise, change digital signal into through data acquisition system (DAS), obtain amount of exercise and time curve through data handling system.

Wherein, grating comprises linear grating or circle grating or flexible linear grating; A grating pair is answered a grating reading head, or a grating pair is answered one group of (a plurality of) grating reading head.

The grating signal conditioning system is nursed one's health the signal of grating reading head output, the grating signal conditioning system is nursed one's health the grating reading head output signal, multiple signals to one group of (a plurality of) read head output synthesize, the final sine voltage signal that obtains 90 ° of two-way phase phasic differences, the input data acquisition system (DAS) is converted to digital signal.

Data acquisition system (DAS) is carried out the multidiameter delay collection, comprise at least No. 2 analog to digital converters (ADC),, amplifier and wave filter etc.

Digital information processing system is displacement, speed, acceleration and angular displacement, angular velocity, angular acceleration and time relation with the digital signal transition relevant with motion of data acquisition system (DAS) output, and the temporal resolution of its measured value is identical with the sampling time interval of analog to digital converter.

Grating is installed in respectively in the relative moving object static and to be measured with grating reading head.When carrying out the line motion measurement, adopt linear grating; When carrying out the angular motion measurement, adopt circle grating or flexible linear grating; The axis of circle grating and the dead in line of angular motion, flexible linear grating entirely is attached to the right cylinder side of axis and angular motion dead in line.

U _x＝h+acosφ (1)

U _y＝k+bsin(φ-φ ₀) (2)

In the formula, h and k-DC component; The amplitude of a and b-AC compounent; φ ₀The nonopiate phase place of-two paths of signals.

Can comprise gain, zero-bit, phase regulating circuit in the signal conditioner, regulate by the mode of automatic or manual, make the amplitude a of the AC compounent in the formula (1) (2) and b equate, DC component h and k are zero, nonopiate phase ₀Be zero.Also can compensate, make by the data processing software mode

U′ _x＝a′cosφ (3)

U′ _y＝a′sinφ (4)

The phase place of the orthogonal signal that grating measuring obtains can be expressed as:

$s\left[n\right]=({\tan }^{-1}\frac{U_y^{\′}\left[n\right]}{U_x^{\′}\left[n\right]}+\mathrm{k\π})---\left(5\right)$

In the formula, n-sample sequence number; K-0,1,2,3,

When the distance of a pitch of grating was λ, corresponding orthogonal signal phase change was 2 π, and shift value can be expressed as:

$D\left[\mathrm{n\Δt}\right]=\frac{\mathrm{\λ}}{2\mathrm{\π}}\×s\left[\mathrm{n\Δt}\right]---\left(6\right)$

In the formula, Δ t-ADC sampling time interval.

Obtain each by (6) and measure displacement constantly and time relation.

When the angle of a pitch of grating was θ, corresponding orthogonal signal phase change was 2 π, and value of angular displacement can be expressed as:

$\mathrm{\Φ}\left[\mathrm{n\Δt}\right]=\frac{\mathrm{\θ}}{2\mathrm{\π}}\×s\left[\mathrm{n\Δt}\right]---\left(7\right)$

In the formula, Δ t-ADC sampling time interval.

Obtain each by (7) and measure angular displacement constantly and time relation.

Corresponding each speed and accekeration is constantly obtained by the first order difference and the second order difference of displacement; Corresponding each angular velocity and angular acceleration values is constantly obtained by the first order difference and the second order difference of angular displacement.

The present invention adopts all kinds of grating pair kinematic parameters to measure, and the line amount of exercise and the moment of momentum of equipment such as turntable, simulation table, tilter, angle vibration table, low frequency linear vibration table carried out in-site measurement and calibration; Obtain displacement, speed, acceleration or angular displacement, angular velocity, the angular acceleration value of any time in the measuring process; And can measure dynamic amount of spin and speed fluctuation rate.

The present invention has following excellent results:

1. motion parameter measurer adopts the accuracy of grating and grating reading head can directly be traceable to length and angular standard, the time standard that the sample frequency of A/D converter can directly be traced to the source, thereby the final motion value of measuring can directly be traceable to time, length or angular metric etc.

2. adopt grating and grating reading head sensitive element as kinematic parameter, grating is separately fixed on the different objects with grating reading head, when relative motion of object, the electric signal that grating reading head output is relevant with amount of exercise, be converted to digital signal through data acquisition system (DAS), after data handling system is handled, obtain amount of exercise and time curve.Adopt the grating of different accuracy grade can obtain the required displacement of the lines or the accuracy of measurement of angular displacement; Adopt the more A/D converter spare of figure place that momental Measurement Resolution is improved greatly; Adopt the higher A/D converter spare of sample frequency that momental temporal resolution is improved greatly.In view of speed, acceleration and angular velocity, angular acceleration are to adopt displacement or angular displacement differentiate are drawn, thereby the movement parameter measurement value that obtains pin-point accuracy that the rises to motion value and that change resolution is in time laid a good foundation.

3. when motion parameter measurer is used to calibrate, the delineation sum of errors alignment error that adopts a plurality of read heads of grating to measure not only can to reduce grating is to the influence of accuracy of measurement, and the error component that the imperfect motion of line motion platform or angular motion platform is introduced compensates, thereby improves accuracy of measurement.

4. compare with laser interferance method, adopt the metering system of grating+read head owing to do not rely on tested movable body surface to the reflection of light feature, thereby the signal to noise ratio (S/N ratio) height, and signal quality is stable.

Description of drawings

Fig. 1 is the motion parameter measurer principle schematic;

Fig. 2 is a line motion measurement principle schematic of the present invention;

Fig. 3 is that the diagonal motion simulation table is carried out the calibrating principle synoptic diagram.

Embodiment

Motion parameter measurer shows as Fig. 1, and it is used for measuring at least in a directional ray amount of exercise or moment of momentum and time relation, contains displacement, speed, acceleration and angular displacement, angular velocity, angular acceleration etc.It comprises at least one grating 1, several grating reading heads 2, grating signal conditioning system 3, data acquisition system (DAS) 4 and data handling system 5, grating 1 is separately fixed on the different objects with grating reading head 2, when relative motion of object, and the grating reading head 2 outputs electric signal relevant with amount of exercise, change digital signal into through data acquisition system (DAS), after data handling system is handled, obtain amount of exercise and time curve.

Wherein, grating comprises linear grating or circle grating or flexible linear grating; A grating pair is answered a grating reading head, or a grating pair is answered one group of (a plurality of) grating reading head.

The grating signal conditioning system is nursed one's health the signal of grating reading head output, the grating signal conditioning system is nursed one's health the grating reading head output signal, multiple signals to one group of (a plurality of) read head output synthesize, final two-way phase place 90 ° the sine voltage signal mutually that obtains, the input data acquisition system (DAS) is converted to digital signal.

Data acquisition system (DAS) is carried out the multidiameter delay collection, comprise at least No. 2 analog to digital converters (ADC),, amplifier and wave filter etc.

Digital information processing system is displacement, speed, acceleration and angular displacement, angular velocity, angular acceleration and time relation with the digital signal transition relevant with motion of data acquisition system (DAS) output, and the temporal resolution of its measured value is identical with the sampling time interval of analog to digital converter.

Grating is installed in respectively in the relative moving object static and to be measured with grating reading head.When carrying out the line motion measurement, adopt linear grating; When carrying out the angular motion measurement, adopt circle grating or flexible linear grating; The axis of circle grating and the dead in line of angular motion, flexible linear grating entirely is attached to the right cylinder side of axis and angular motion dead in line.

U _x＝h+acosφ (1)

U _y＝k+bsin(φ-φ ₀) (2)

In the formula, h and k-DC component; The amplitude of a and b-AC compounent; φ ₀The nonopiate phase place of-two paths of signals.

Can comprise gain, zero-bit, phase regulating circuit in the signal conditioner, regulate by the mode of automatic or manual, make the amplitude a of the AC compounent in the formula (1) (2) and b equate, DC component h and k are zero, nonopiate phase ₀Be zero.Also can compensate, make by the data processing software mode

U′ _x＝a′cosφ (3)

U′ _y＝a′sinφ (4)

The phase place of the orthogonal signal that grating measuring obtains can be expressed as:

$s\left[n\right]=({\tan }^{-1}\frac{U_y^{\′}\left[n\right]}{U_x^{\′}\left[n\right]}+\mathrm{k\π})---\left(5\right)$

In the formula, n-sample sequence number; K-0,1,2,3,

When the distance of a pitch of grating was λ, corresponding orthogonal signal phase change was 2 π, and shift value can be expressed as:

$D\left[\mathrm{n\Δt}\right]=\frac{\mathrm{\λ}}{2\mathrm{\π}}\×s\left[\mathrm{n\Δt}\right]---\left(6\right)$

In the formula, Δ t-ADC sampling time interval.

Obtain each by (6) and measure displacement constantly and time relation.

When the angle of a pitch of grating was θ, corresponding orthogonal signal phase change was 2 π, and value of angular displacement can be expressed as:

$\mathrm{\Φ}\left[\mathrm{n\Δt}\right]=\frac{\mathrm{\θ}}{2\mathrm{\π}}\×s\left[\mathrm{n\Δt}\right]---\left(7\right)$

In the formula, Δ t-ADC sampling time interval.

Obtain each by (7) and measure angular displacement constantly and time relation.

Corresponding each speed and accekeration is constantly obtained by the first order difference and the second order difference of displacement; Corresponding each angular velocity and angular acceleration values is constantly obtained by the first order difference and the second order difference of angular displacement.

Embodiment one, the line motion measurement

As Fig. 2, linear grating 1 is installed on the online motion platform 6 static supports, on the read head 2 mounted movable parts; Also read head 2 can be installed on the online motion platform 6 static supports, on the linear grating 1 mounted movable parts.It is parallel with direction of motion to adjust linear grating, adjusts the relative position of read head 2 and grating 1, makes the output of read head 2 signals normal.Data acquisition system (DAS) 4 in the motion parameter measurer is used to gather grating and by the electric signal of school sensor.

The two-way phase differential of line grating read head output is 90 ° a orthogonal electrical signal, behind signal conditioner, can be expressed as formula (1) and (2), carry out nonlinear compensation and displacement calculating by formula (3), (4) and (5), obtain a series of by formula (6) or the displacement of (7) acquisition and the measurement result of time relationship, the measurement result that the speed in corresponding each moment and accekeration are obtained speed, acceleration and time relationship by the first order difference and the second order difference of displacement.

Embodiment two, the calibration of angular motion simulation table and the fluctuation of speed, dynamically tachometric survey

The present invention can be used for all kinds of angular motion simulation turntables (hereinafter to be referred as turntable) are calibrated.As Fig. 3, utilize turntable table top 7 or axle head screw hole that mandrel 8 is installed.Rotating table is adjusted mandrel, and its axis of rotation is overlapped with the axis of rotation of turntable shaft.Grating 1 is installed on mandrel 8, grating is fixed on the mandrel 8 with pressure cap 9.Grating reading head 2 is installed in relatively rotates the static place of axle.Adjust the distance and the angle position of read head 2 and grating 1, make the read head output signal normal.Adopt motion parameter measurer (signal processing) to measure the control signal of grating and turntable, and handle.Carry out nonlinear compensation and angular displacement calculating according to formula (3), (4) and (7), obtain the angular displacement of a series of as (7) and the measurement result of time relationship, the measurement result that the angular velocity in corresponding each moment and angular acceleration values are obtained angular velocity, angular acceleration and time relationship by the first order difference and the second order difference of angular displacement.By compare the calibration turntable with the turntable control signal.

When carrying out the fluctuation of speed and dynamic tachometric survey with the coaxial installation of grating and rotation axis, measurement result by formula (7) is handled by the first order difference and the second order difference of angular displacement by angular velocity and angular acceleration values, obtain the time dependent relation of rotating speed (being dynamic rotating speed amount), handle obtaining fluctuation of speed value as required.

Claims (10)

1. motion parameter measurer, it is characterized in that, grating and grating reading head are separately fixed on the object of two relative motions, the electric signal relevant that grating reading head output is read from grating with amount of exercise, change digital signal into through data acquisition system (DAS), obtain amount of exercise and time curve through data handling system.

2. motion parameter measurer according to claim 1 is characterized in that, grating comprises linear grating or circle grating or flexible linear grating; A grating pair is answered a grating reading head, or a grating pair is answered one group of grating reading head.

3. motion parameter measurer according to claim 1, it is characterized in that, the grating signal conditioning system is nursed one's health the grating reading head output signal, multiple signals to group number-reading head output synthesize, the final sine voltage signal that obtains 90 ° of two-way phase phasic differences, the input data acquisition system (DAS) is converted to digital signal.

4. motion parameter measurer according to claim 1 is characterized in that data acquisition system (DAS) is the multidiameter delay collection, comprises at least No. 2 analog to digital converters, amplifier and wave filter.

5. motion parameter measurer according to claim 1, it is characterized in that, digital information processing system is displacement, speed, acceleration and angular displacement, angular velocity, angular acceleration and time relation with the digital signal transition relevant with motion of data acquisition system (DAS) output, and the temporal resolution of its measured value is identical with the sampling time interval of analog to digital converter; Digital information processing system is meant that all kinds of computing machines, digital signal processor or other have the circuit unit of digital signal processing capability.

6. motion parameter measurer according to claim 2 is characterized in that, grating is installed in respectively in the relative moving object static and to be measured with grating reading head.When carrying out the line motion measurement, adopt linear grating; When carrying out the angular motion measurement, adopt circle grating or flexible linear grating; The axis of circle grating and the dead in line of angular motion, linear grating entirely is attached to the right cylinder side of axis and angular motion dead in line.

7. motion parameter measurer according to claim 3 is characterized in that, grating signal conditioning system output two-way phase intervals is that 90 ° sine voltage signal can be expressed as:

U _x＝h+a?cos?φ

U _y＝k+b?sin?(φ-φ ₀)

Comprise gain, zero-bit, phase regulating circuit in the signal condition system, regulate by the mode of automatic or manual; Or compensate by the data processing software mode, make

U _x′＝a′cos?φ

U _yThe phase meter of the orthogonal signal that '=a ' sin φ grating measuring obtains is shown:

$s\left[n\right]=(\mathrm{ta}{n}^{-1}\frac{U_y^{\′}\left[n\right]}{U_x^{\′}\left[n\right]}+\mathrm{k\π})$

8. by the described motion parameter measurer of claim 3, when the distance of a pitch of grating was λ, corresponding orthogonal signal phase change was 2 π, and the shift value of a certain moment n Δ t is expressed as:

$D\left[\mathrm{n\Δt}\right]=\frac{\mathrm{\λ}}{2\mathrm{\π}}\×s\left[\mathrm{n\Δt}\right]$

9. by the described motion parameter measurer of claim 3, when the angle of a pitch of grating was θ, corresponding orthogonal signal phase change was 2 π, and the value of angular displacement of a certain moment n Δ t is expressed as:

$\mathrm{\Φ}\left[\mathrm{n\Δt}\right]=\frac{\mathrm{\θ}}{2\mathrm{\π}}\×s\left[\mathrm{n\Δt}\right]$

10. motion parameter measurer according to claim 3 is characterized in that, corresponding each speed and accekeration is constantly obtained by the first order difference and the second order difference of displacement; Corresponding each angular velocity and angular acceleration values is constantly obtained by the first order difference and the second order difference of angular displacement.

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