CN103217139B - The online self-calibrating method of a kind of angular displacement sensor based on double testing head - Google Patents

Abstract

The online self-calibrating method of a kind of angular displacement sensor based on double testing head, described method is being demarcated the read head that on the stator of angular displacement sensor, layout two is identical, can carry out synchro measure to same single-revolution object angle of revolution displacement, connect firmly by the demarcation rotor of angular displacement sensor and the rotating part of measurand, turn round one complete 360 °, record the indicating value of two read heads during a series of specific position, obtain the measuring error function of sensor after data processing is carried out to indicating value, realize being demarcated the online self-calibration of angular displacement sensor.This self-calibrating method is according to the circumference closure principle in measurement of angle, two read heads arranged according to certain position relation are utilized to carry out synchro measure, by processing measurement data, the online self-calibration of sensor can be realized under the condition not having standard and other High-Accuracy Angular Displacement Measurement instrument.

Description

The online self-calibrating method of a kind of angular displacement sensor based on double testing head

Technical field

The invention belongs to accurate displacement fields of measurement, be specifically related to the online self-calibrating method of a kind of angular displacement sensor.

Background technology

Angle displacement measurement is one of the most basic geometric measurement.Angular displacement sensor is angle displacement measurement element.The Typical Representative of this kind of angular displacement sensor has: grating, inductosyn, selsyn, rotary transformer and time-grating sensor etc.Because, there is error when this kind of sensor carries out angle displacement measurement in the deviations such as processing, installation, electric parameter.Usually, by demarcating this kind of sensor, measuring accuracy can be improved.But current known scaling method generally needs, by standard or more high-precision angle displacement measurement instrument, to be not suitable for carrying out online.

Summary of the invention

The present invention is directed to the problems referred to above, disclose the online self-calibrating method of a kind of angular displacement sensor based on double testing head.This self-calibrating method is according to the circumference closure principle in measurement of angle, two read heads arranged according to certain space relation are utilized to carry out synchro measure, by processing measurement data, the online self-calibration of sensor can be realized under the condition not having standard and other High-Accuracy Angular Displacement Measurement instrument.

The technical solution used in the present invention is:

Two identical, synchro measure can be carried out to the angle of revolution displacement of same single-revolution object read heads are arranged being demarcated on the stator of angular displacement sensor according to certain space relation, i.e. gauge head, connect firmly by the demarcation rotor of angular displacement sensor and the rotating part of measurand, turn round one complete 360 °, record the indicating value of a series of specific position two read head, obtain after data processing is carried out to indicating value by the measuring error function demarcating angular displacement sensor, realize being demarcated the online self-calibration of angular displacement sensor.

Described two identical, following implication can be comprised to the read head that synchro measure is carried out in the angular displacement of same single-revolution object: each read head all independently can be used to complete angle displacement measurement; Two read head measuring error are identical; Two read heads can be measured in the angular displacement of synchronization to same single-revolution object.

Described layout according to certain space relation refers to that two read heads are arranged in circumferentially same and at a distance of angle are described angle is apart allow ± the deviation of 2 '.Described M for be not equal to be demarcated in angular displacement sensor measuring error the positive integer of integral multiple of the main error frequency that comprises and these main frequencys, under this prerequisite, M is taken as prime number, as 17,19,23,407 ... time demarcate effect better.

The described indicating value recording a series of specific position two read head refers to: when one of them read head indicating value is time (wherein: i=0,1,2, n-1; N for be greater than demarcated angular displacement sensor measuring error comprise the positive integer of the most high level error frequency 2 times), record current read head indicating value and another read head indicating value respectively, obtain two indicating value sequences, be designated as { A respectively _iand { B _i.

Describedly data processing is carried out to indicating value comprise: by described { A _iand { B _itwo indicating value sequences subtract each other item by item and obtain a sequence of differences { C _i; To { C _icarry out discrete Fourier transformation, obtain the amplitude spectrum { Am of its correspondence _iand phase spectrum { P _i.

After described data processing, the measuring error function of sensor can be expressed as formula (1),

δ(θ)=A ₀+k(θ) （1）

Wherein: δ (θ) is measuring error function; θ is measured angle displacement;

$k\left(\mathrm{\θ}\right)=\underset{i=1}{\overset{n/2-1}{\mathrm{\Σ}}}\{\frac{A{m}_i}{2\×\sin \left(\frac{i\×A{m}_0}{2}\right)}\×\sin (i\×\mathrm{\θ}+P_i-\frac{\mathrm{\π}}{2}-\frac{A{m}_0}{2})\}$

$A_0=\frac{\max \left(k\left(\mathrm{\θ}\right)\right)+\min \left(k\left(\mathrm{\θ}\right)\right)}{2};$

Wherein: max (k (θ)) is the maximal value of k (θ); Min (k (θ)) is the minimum value of k (θ).

The described online self-calibration of sensor that realizes refers to, after obtaining sensor measurement errors function δ (θ), the indicating value f (θ) of sensor θ at an arbitrary position can under the condition that not need standard and other high precision measuring instrument, and through type (2) obtains the calibration value Ca (θ) of its correspondence.

Ca(θ)=f(θ)-δ(θ) （2）。

Key point of the present invention is:

(1) demarcated and angular displacement sensor stator had two identical read heads;

(2) two identical read heads are arranged in circumferentially same and apart

(3) read head is positioned at wherein during position, record the indicating value of two read heads respectively, obtain two indicating value sequence { A _iand { B _i;

(4) by two indicating value sequence { A _iand { B _isubtract each other item by item and obtain sequence of differences { C _i;

(5) to sequence { C _icarry out discrete Fourier transformation, obtain the amplitude spectrum { Am of its correspondence _iand phase spectrum { P _i;

(6) the function representation δ (θ) of measuring error is obtained according to formula (1);

(7) obtain the calibration value of optional position according to formula (2), realize the online self-calibration of sensor.Compared with the prior art, advantage of the present invention is:

(1) demarcate employing two read heads to realize, need not standard or high precision with reference to female instrument, can self-calibration be realized;

(2) relative to traditional full combined method and pointwise standardization, the sampling number of described self-calibrating method is few;

(3) owing to solving error function, described self-calibration can be demarcated arbitrfary point within the scope of complete cycle, and existing full combined method and point by point method can only be demarcated finite point;

(4) two read head structural parameters etc. are all identical, can be integrated in a sensor, realize real-time online error calibration.

Accompanying drawing explanation

Fig. 1 is the magnetic grid angular displacement sensor schematic diagram with two read heads;

Fig. 2 is the A-A sectional view of Fig. 1.

1-read head A; 2-read head B; 3-disk; 4-rotor; 5-stator.

Embodiment

Below in conjunction with Figure of description, technical scheme of the present invention is described in further detail.

See Fig. 1 and Fig. 2, a kind of online self-calibrating method of error of angular displacement sensor system is: in the magnetic induction sensor be made up of read head A1, read head B2, disk 3, rotor 4 and stator 5, read head A1 and read head B2 is arranged in the circumferentially same of stator 5, at a distance of 33670 °, disk 3 and rotor are fixed and connect firmly with the rotating part of measurand, turn round with measurand, two read heads can carry out reading to disk simultaneously, realize the angle displacement measurement to measurand, measurand is returned and is circled, be 0 in read head A indicating value time, record read head A and read head B indicating value respectively, obtain two indicating value sequences, be designated as { A _iand { B _i, two indicating value sequence { A _iand { B _isubtract each other item by item and obtain sequence of differences { C _i, to sequence { C _icarry out discrete Fourier transformation, obtain the amplitude spectrum { Am of its correspondence _iand phase spectrum { P _i, the measuring error function of magnetic induction sensor is formula (3).

δ(θ)=A ₀+k(θ) （3）

Wherein: $k\left(\mathrm{\θ}\right)=\underset{i=1}{\overset{127}{\mathrm{\Σ}}}\{\frac{A{m}_i}{2\×\sin \left(\frac{i\×A{m}_0}{2}\right)}\×\sin (i\×\mathrm{\θ}+P_i-\frac{\mathrm{\π}}{2}-\frac{A{m}_0}{2})\}$

$A_0=\frac{\max \left(k\left(\mathrm{\θ}\right)\right)+\min \left(k\left(\mathrm{\θ}\right)\right)}{2}.$

After obtaining sensor measurement errors function δ (θ), the indicating value f (θ) of sensor θ at an arbitrary position can under the condition that not need standard and other high precision measuring instrument, and through type (2) obtains the calibration value Ca (θ) of its correspondence:

Ca(θ)=f(θ)-δ(θ) （2）。

Claims (4)

1. the online self-calibrating method of the angular displacement sensor based on double testing head, it is characterized in that: arrange two identical, synchro measure can be carried out to same single-revolution object angle of revolution displacement read heads being demarcated on the stator of angular displacement sensor, connect firmly by the demarcation rotor of angular displacement sensor and the rotating part of measurand, turn round one complete 360 °, record the indicating value of two read heads during a series of specific position, obtain the measuring error function of sensor after data processing is carried out to indicating value, realize being demarcated the online self-calibration of angular displacement sensor;

The position relationship of described two read heads is: be arranged in circumferentially same and apart allow ± the deviation of 2 ', wherein M for be not equal to be demarcated in angular displacement sensor measuring error the positive integer of integral multiple of the main error frequency that comprises and these main frequencys, under this prerequisite, M is taken as prime number;

The indicating value of described a series of specific position two read head is: when one of them read head indicating value is 0, time, record current read head indicating value and another read head indicating value respectively, obtain two indicating value sequence { A _iand { B _i, wherein: i=0,1,2 ..., n-1; N for be greater than demarcated angular displacement sensor measuring error comprise the positive integer of the most high level error frequency 2 times;

Describedly data processing is carried out to indicating value be: by { A _iand { B _isubtract each other item by item and obtain a sequence of differences { C _i; To { C _icarry out discrete Fourier transformation, obtain the amplitude spectrum { Am of its correspondence _iand phase spectrum { P _i, thus according to amplitude spectrum { Am _iand phase spectrum { P _ireconstruct sensor measurement errors function, obtain the calibration value of optional position, realize being demarcated the online self-calibration of angular displacement sensor; After described data processing, the measuring error function representation of sensor is formula (1),

δ(θ)＝A ₀+k(θ) (1)

Wherein: δ (θ) is measuring error function; θ is measured angle displacement;

Wherein: max (k (θ)) is the maximal value of k (θ); Min (k (θ)) is the minimum value of k (θ).

2. the online self-calibrating method of angular displacement sensor according to claim 1, it is characterized in that: after obtaining sensor measurement errors function δ (θ), the indicating value f (θ) of sensor θ at an arbitrary position can under the condition that not need standard and other high precision measuring instrument, through type (2) obtains the calibration value Ca (θ) of its correspondence, Ca (θ)=f (θ)-δ (θ).

3. the online self-calibrating method of angular displacement sensor according to claim 1 and 2, is characterized in that: described M gets 17,19,23,407 ... time demarcate effect better.

4. the online self-calibrating method of angular displacement sensor according to claim 3, is characterized in that: described each read head all independently can be used to complete angle displacement measurement; Two read head measuring error are identical; Two read heads can be measured in the angular displacement of synchronization to same single-revolution object.