CN111649774B - Hardware self-correction system and method for angle measurement error of rotary transformer - Google Patents
Hardware self-correction system and method for angle measurement error of rotary transformer Download PDFInfo
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- CN111649774B CN111649774B CN202010580407.1A CN202010580407A CN111649774B CN 111649774 B CN111649774 B CN 111649774B CN 202010580407 A CN202010580407 A CN 202010580407A CN 111649774 B CN111649774 B CN 111649774B
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- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
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Abstract
The invention relates to a hardware self-correcting system and method for angle measurement errors of a rotary transformer, which comprises the following steps: the device comprises a servo control unit, an amplitude correction unit, a phase angle correction unit and an error characterization unit. The servo control unit is used for controlling the load to stably rotate according to the command angular speed. The amplitude correction unit is used for adjusting the amplitude of sine and cosine signals output by the rotary transformer and eliminating amplitude errors. The phase angle correction unit is used for adjusting the phase difference of the rotary-variable output sine and cosine signals and eliminating the quadrature error. And the rotation variation error characterization unit sends an instruction angular speed to the control servo control unit, performs frequency spectrum analysis on the resolving angular speed output by the servo controller, and transmits the second harmonic amplitude Amp to the amplitude correction unit and the phase angle correction unit as a basis for adjusting the amplitude correction unit and the phase angle correction unit. The method is suitable for correcting and compensating amplitude errors and phase angle errors of the rotary transformer, and can greatly improve the angle measurement precision of the rotary transformer.
Description
Technical Field
The invention relates to a hardware self-correction system and method for angle measurement errors of a rotary transformer.
Background
The rotary transformer has high reliability and good force and heat environment adaptability, and is widely applied to the field of aerospace high-precision angle measurement.
The rotary transformer acquires envelopes of two paths of amplitude-modulated signals by detecting through a special demodulation chip, and then acquires angular position information through a demodulation algorithm. Ideally, the envelope signal after detection should be an orthogonal sine and cosine signal, but due to factors such as amplitude output asymmetry of the rotary-change output signal, non-ideal orthogonality, inductance harmonics, phase offset of the carrier reference signal, and the like, the envelope signal after detection often contains direct current offset, amplitude asymmetry and phase offset, which may cause a large demodulation error. The rotation-variant demodulation errors mainly include amplitude errors, quadrature errors and function errors. The frequency of the amplitude error and the quadrature error is represented as a double frequency of the rotating frequency, and the frequency of the main component of the functional error is also a double frequency of the rotating frequency.
In summary, errors reflecting frequency-rotation frequency doubling in angular velocity caused by inconsistent and non-orthogonal amplitudes of sine and cosine signals output by the resolver and waveform distortion (function errors) are main components of the resolver angle measurement errors, which seriously affect the resolver angle measurement accuracy and further affect the control accuracy of the servo system.
The existing method for correcting and compensating the error of the rotary transformer is to calibrate the rotary transformer by using a high-precision sensor, look up a table for compensation according to a calibration value, perform the process on a rotary transformer assembly, and change the error characteristic of the rotary transformer installed in a servo system along with the relative position of a rotary transformer stator rotor, so that a large compensation error exists.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the hardware self-correction system and method for the angle measurement error of the rotary transformer overcome the defects of the prior art, correct the error which is reflected as the rotational frequency doubling of the rotary transformer in angular speed and is caused by inconsistent amplitude, non-orthogonality and waveform distortion (function error) of the sine and cosine signals output by the rotary transformer, improve the precision of the angle measurement of the rotary transformer, further improve the control precision of a servo system, and are suitable for the correction and compensation of the amplitude error and the phase angle error of the rotary transformer (called rotary transformer for short).
The technical scheme adopted by the invention is as follows: a resolver angular error hardware self-correction system, comprising: the device comprises a servo control unit, an amplitude correction unit, a phase angle correction unit and an error characterization unit;
the servo control unit comprises a servo controller, a servo motor, a load, a rotary transformer and a rotary transformer demodulator; the rotary transformer is installed on a load, the rotary transformer demodulator outputs an excitation signal sig _ jl to the rotary transformer, the rotary transformer induces a sine winding output signal sig _ sin and a cosine winding output signal sig _ cos which are related to a load angular position theta, and the sine winding output signal sig _ sin and the cosine winding output signal sig _ cos pass through an amplitude correction unit and a phase angle correction unit to obtain a sine winding correction output signal sig _ sin _ c2 and a cosine winding correction output signal sig _ cos _ c2 which are transmitted to the rotary transformer demodulator; the rotary-transformer demodulator demodulates the sine-winding correction output signal sig _ sin _ c2 and the cosine-winding correction output signal sig _ cos _ c2 to obtain a resolving angular position theta _ RDC, transmits the resolving angular position theta _ RDC to the servo controller, and calculates to obtain a resolving angular velocity Vel _ RDC; the servo controller calculates and outputs control current to the servo motor according to the difference between the command angular velocity Vel _ zl output by the error representation unit and the resolving angular velocity Vel _ RDC; the servo motor outputs torque to drive a load to track the command angular speed Vel _ zl;
the amplitude correction unit adjusts the amplitude of sine and cosine winding output signals output by the rotary transformer and eliminates amplitude errors; the phase angle correction unit adjusts the phase difference of sine and cosine winding output signals output by the amplitude correction unit and eliminates orthogonal errors;
the rotation variation error characterization unit sends an instruction angular speed to the control servo controller, receives the resolving angular speed of the servo controller, performs spectrum analysis on the resolving angular speed to obtain a second harmonic amplitude as the rotation variation error, and transmits the second harmonic amplitude Amp to the amplitude correction unit and the phase angle correction unit as the basis for adjusting the amplitude correction unit and the phase angle correction unit.
The amplitude correction unit comprises a voltage follower and a forward amplifier and is used for correcting an angle resolving error caused by the inconsistency of amplitudes of the sine winding output signal sig _ sin and the cosine winding output signal sig _ cos;
if the cosine winding output signal sig _ cos is taken as a reference, the sine winding output signal sig _ sin is transmitted to a voltage follower, output impedance is improved, a subsequent sine winding output signal sig _ sin _ f1 is obtained and then output to a forward amplifier, the subsequent sine winding output signal sig _ sin _ f1 is amplified or reduced according to a second harmonic error amplitude Amp output by an error characterization unit, and an amplitude correction sine signal sig _ sin _ c1 and an amplitude correction cosine signal sig _ cos _ c1 are obtained and output to a phase angle correction unit;
if the sine winding output signal sig _ sin is taken as a reference, the cosine winding output signal sig _ cos is transmitted to a voltage follower, output impedance is improved, a subsequent cosine winding output signal sig _ cos _ f1 is obtained and then output to a forward amplifier, the subsequent cosine winding output signal sig _ cos _ f1 is amplified or reduced according to a second harmonic error amplitude Amp output by an error characterization unit, and an amplitude correction cosine signal sig _ sin _ c1 and an amplitude correction cosine signal sig _ cos _ c1 are obtained and output to a phase angle correction unit.
The phase angle correction unit comprises a voltage follower, a forward amplifier and a bidirectional adder; the phase angle correction unit corrects an angle resolving error caused by non-ideal orthogonality of a sine winding output signal sig _ sin and a cosine winding output signal sig _ cos;
if the cosine winding output signal sig _ cos is taken as a reference, outputting an amplitude correction sine signal sig _ sin _ c1 to a voltage follower, improving output impedance to obtain a subsequent sine winding output signal sig _ sin _ f2, then outputting the signal to a forward amplifier, amplifying or reducing the subsequent sine winding output signal sig _ sin _ f2 according to a second harmonic error amplitude Amp output by an error characterization unit to obtain a phase angle error correction value sig _ sin _ e, and outputting the phase angle error correction value sig _ sin _ e to a bidirectional adder; the bidirectional adder carries out addition and subtraction of a phase angle error correction quantity sig _ sin _ e on the amplitude correction cosine signal sig _ cos _ c1 according to the second harmonic error amplitude Amp output by the error characterization unit to obtain a phase angle correction sine signal sig _ sin _ c2 and a phase angle correction cosine signal sig _ cos _ c2, and outputs the phase angle correction sine signal sig _ sin _ c 3526 to the resolver;
if the sine winding output signal sig _ sin is taken as a reference, the amplitude correction cosine signal sig _ cos _ c1 is output to a voltage follower, output impedance is improved, a subsequent cosine winding output signal sig _ cos _ f2 is obtained and then output to a forward amplifier, subsequent cosine winding output signal sig _ cos _ f2 is amplified or reduced according to a second harmonic error amplitude Amp output by an error characterization unit, a phase angle error correction value sig _ cos _ e is obtained and output to a bidirectional adder; the bidirectional adder carries out addition and subtraction of a phase angle error correction amount sig _ cos _ e on the amplitude correction sine signal sig _ sin _ c1 according to the second harmonic error amplitude Amp output by the error characterization unit to obtain a phase angle correction sine signal sig _ sin _ c2 and a phase angle correction cosine signal sig _ cos _ c2, and outputs the phase angle correction sine signal sig _ sin _ c2 and the phase angle correction cosine signal sig _ cos _ c2 to the resolver.
The second harmonic amplitude Amp is the amplitude at the position of the rotational speed second frequency multiplication frequency Frq in the frequency spectrum analysis result;
the rotational speed frequency Frq is the angular speed multiplied by the number of rotational pole pairs divided by 180.
According to the magnitude of the second harmonic error amplitude Amp, the adjusting method of the forward amplifier in the amplitude correction unit, the forward amplifier in the phase angle correction unit and the bidirectional adder is as follows:
step 2, judging whether the second harmonic error amplitude Amp is smaller: if yes, continuing to reduce the amplification ratio of the forward amplifier of the amplitude correction unit; if not, adjusting the amplification ratio of a forward amplifier of the phase angle correction unit to a minimum value a, setting a bidirectional adder of the phase angle correction unit as an adder, and judging whether the amplitude of the second harmonic error amplitude Amp is reduced: if yes, increasing the amplification ratio of a positive amplifier of the phase angle correction unit, and entering step 3; if not, setting the bidirectional adder of the phase angle correction unit as a subtracter, and entering the step 4;
step 3, judging whether the second harmonic error amplitude Amp is smaller: if yes, continuously increasing the amplification ratio of the phase angle correction unit forward amplifier; if not, the method ends;
step 4, judging whether the second harmonic error amplitude Amp is smaller, if so, continuing to increase the amplification ratio of the phase angle correction unit forward amplifier; if not, the method ends.
A hardware self-correcting method for angle measurement errors of a rotary transformer comprises the following steps:
step one, sending an instruction angular velocity to a servo controller through an error characterization unit, and controlling a servo motor to drive a load to rotate at the instruction angular velocity through the servo controller;
the rotary transformer induces a sine winding output signal sig _ sin and a cosine winding output signal sig _ cos related to a load angular position theta according to an excitation signal sig _ jl output by the rotary transformer demodulator, and sends the signals to the amplitude correction unit and the phase angle correction unit;
carrying out spectrum analysis on the resolving angular velocity sent by the servo controller through an error characterization unit, and transmitting a second harmonic amplitude Amp in an analysis result to an amplitude correction unit and a phase angle correction unit;
secondly, the amplitude correction unit and the phase angle correction unit respectively adjust the amplitude and the phase difference of the sine winding output signal sig _ sin and the cosine winding output signal sig _ cos according to the amplitude of the second harmonic amplitude Amp to obtain a sine winding correction output signal sig _ sin _ c2 and a cosine winding correction output signal sig _ cos _ c2 which are transmitted to the resolver demodulator;
thirdly, demodulating the sine winding correction output signal sig _ sin _ c2 and the cosine winding correction output signal sig _ cos _ c2 by the rotary transformer demodulator to obtain a resolving angular position theta _ RDC, and transmitting the resolving angular position theta _ RDC to the servo controller;
and step four, calculating by the servo controller to obtain a resolved angular velocity Vel _ RDC, calculating according to the difference between the command angular velocity Vel _ zl and the resolved angular velocity Vel _ RDC, outputting a control current to the servo motor, and returning to the step one.
In the second step, the amplitude correction unit adjusts the amplitude of the sine winding output signal sig _ sin and the cosine winding output signal sig _ cos according to the amplitude of the second harmonic error amplitude Amp as follows:
if the cosine winding output signal sig _ cos is taken as a reference, the sine winding output signal sig _ sin is transmitted to a voltage follower, output impedance is improved, a subsequent sine winding output signal sig _ sin _ f1 is obtained and then output to a forward amplifier, the subsequent sine winding output signal sig _ sin _ f1 is amplified or reduced according to a second harmonic error amplitude Amp, an amplitude correction sine signal sig _ sin _ c1 and an amplitude correction cosine signal sig _ cos _ c1 are obtained and output to a phase angle correction unit;
if the sine winding output signal sig _ sin is taken as a reference, the cosine winding output signal sig _ cos is transmitted to a voltage follower, output impedance is improved, a subsequent cosine winding output signal sig _ cos _ f1 is obtained and then output to a forward amplifier, the subsequent cosine winding output signal sig _ cos _ f1 is amplified or reduced according to a second harmonic error amplitude Amp, and an amplitude correction cosine signal sig _ sin _ c1 and an amplitude correction cosine signal sig _ cos _ c1 are obtained and output to a phase angle correction unit.
In the second step, the phase angle correction unit adjusts the phase difference between the sine winding output signal sig _ sin and the cosine winding output signal sig _ cos according to the magnitude of the second harmonic error amplitude Amp as follows:
if the cosine winding output signal sig _ cos is taken as a reference, outputting an amplitude correction sine signal sig _ sin _ c1 to a voltage follower, improving output impedance to obtain a subsequent sine winding output signal sig _ sin _ f2, then outputting the signal to a forward amplifier, amplifying or reducing the subsequent sine winding output signal sig _ sin _ f2 according to a second harmonic error amplitude Amp to obtain a phase angle error correction value sig _ sin _ e, and outputting the phase angle error correction value sig _ sin _ e to a bidirectional adder; the bidirectional adder carries out addition and subtraction of a phase angle error correction amount sig _ sin _ e on the amplitude correction cosine signal sig _ cos _ c1 according to the second harmonic error amplitude Amp to obtain a phase angle correction sine signal sig _ sin _ c2 and a phase angle correction cosine signal sig _ cos _ c2, and outputs the phase angle correction sine signal sig _ sin _ c 3526 to the resolver demodulator;
if the sine winding output signal sig _ sin is taken as a reference, outputting an amplitude correction cosine signal sig _ cos _ c1 to a voltage follower, improving output impedance to obtain a subsequent cosine winding output signal sig _ cos _ f2, then outputting to a forward amplifier, amplifying or reducing the subsequent cosine winding output signal sig _ cos _ f2 according to a second harmonic error amplitude Amp to obtain a phase angle error correction value sig _ cos _ e, and outputting to a bidirectional adder; the bidirectional adder carries out addition and subtraction of a phase angle error correction amount sig _ cos _ e on the amplitude correction sine signal sig _ sin _ c1 according to the second harmonic error amplitude Amp to obtain a phase angle correction sine signal sig _ sin _ c2 and a phase angle correction cosine signal sig _ cos _ c2, and outputs the phase angle correction sine signal sig _ sin _ c 3526 to the resolver demodulator.
In the second step, according to the magnitude of the second harmonic error amplitude Amp, the method for adjusting the forward amplifier in the amplitude correction unit, the forward amplifier in the phase angle correction unit and the bidirectional adder is as follows:
step 2, judging whether the second harmonic error amplitude Amp is smaller: if yes, continuing to reduce the amplification ratio of the forward amplifier of the amplitude correction unit; if not, adjusting the amplification ratio of a forward amplifier of the phase angle correction unit to a minimum value a, setting a bidirectional adder of the phase angle correction unit as an adder, and judging whether the amplitude of the second harmonic error amplitude Amp is reduced: if yes, increasing the amplification ratio of a positive amplifier of the phase angle correction unit, and entering step 3; if not, setting the bidirectional adder of the phase angle correction unit as a subtracter, and entering the step 4;
step 3, judging whether the second harmonic error amplitude Amp is smaller: if yes, continuously increasing the amplification ratio of the phase angle correction unit forward amplifier; if not, the method ends;
step 4, judging whether the second harmonic error amplitude Amp is smaller, if so, continuing to increase the amplification ratio of the phase angle correction unit forward amplifier; if not, the method ends.
Compared with the prior art, the invention has the beneficial effects that:
(1) the rotary transformer amplitude error self-correction device is provided with a rotary transformer output sine and cosine signal amplitude correction unit, a servo control unit controls a load to rotate at a constant rotating speed, and the amplitude correction unit is adjusted according to a frequency spectrum analysis value of a rotary transformer resolving angular velocity to realize the self-correction of the amplitude error of the rotary transformer.
(2) The phase angle correction unit is arranged, the servo control unit controls the load to rotate at a constant rotating speed, and the phase angle correction unit is adjusted according to the frequency spectrum analysis value of the resolver resolving angular speed, so that the self-correction of the phase angle error of the rotary transformer is realized.
(3) The invention is provided with a rotation variation error representation unit, a servo control unit controls the load to rotate at a constant rotating speed, and the rotation variation error is represented according to the amplitude of the second-frequency of the rotation variation rotating speed in the frequency spectrum analysis result of the rotation variation resolving angular speed, so that the self-calibration of the rotation variation angle measurement error is realized.
(4) The invention utilizes the error frequency characteristic of the rotary transformer to carry out self calibration and self compensation, and does not use a sensor with higher precision to calibrate the rotary transformer. The method does not need a complex switching tool, and only needs to add a simple circuit between the rotary transformer body and the demodulator, so that the method is easy to realize.
Drawings
FIG. 1 is a general block diagram of a hardware self-calibration system for resolver angle measurement error;
FIG. 2 is a schematic diagram of an amplitude correction unit;
FIG. 3 is a schematic diagram of a phase angle correction unit;
FIG. 4 is a schematic diagram of an error characterization unit;
FIG. 5 is a flow chart of a hardware self-calibration method for resolver angle measurement error.
Detailed Description
The invention is further illustrated by the following examples.
As shown in fig. 1, the hardware self-calibration system for angle measurement error of a resolver according to the present invention includes: the device comprises a servo control unit, an amplitude correction unit, a phase angle correction unit and an error characterization unit;
the servo control unit is used for controlling the load to stably rotate according to the command angular speed.
And the amplitude correction unit is used for adjusting the amplitude of the output signal of the rotary transformer output sine and cosine winding and eliminating amplitude errors.
And the phase angle correction unit is used for adjusting the phase difference of the output signals of the rotary transformer output sine and cosine windings and eliminating non-orthogonal errors.
And the rotation variation error characterization unit is used for sending an instruction angular speed to the control servo control unit, carrying out spectrum analysis on the calculated angular speed output by the servo controller, using the amplitude at the second-frequency-multiplication position of the rotation variation rotating speed to characterize the rotation variation error, and transmitting the second harmonic amplitude Amp to the amplitude correction unit and the phase angle correction unit to be used as a basis for adjusting the amplitude correction unit and the phase angle correction unit.
1. Servo control unit
As shown in fig. 1, the servo control unit includes a servo controller, a servo motor, a load, a resolver, and a resolver demodulator; the rotary transformer is installed on a load, the rotary transformer demodulator outputs an excitation signal sig _ jl to the rotary transformer, the rotary transformer induces a sine winding output signal sig _ sin and a cosine winding output signal sig _ cos related to a load angular position theta, the two signals pass through an amplitude correction unit and a phase angle correction unit to obtain a sine winding correction output signal sig _ sin _ c2 and a cosine winding correction output signal sig _ cos _ c2, the two signals are transmitted to the rotary transformer demodulator, the rotary transformer demodulator demodulates the two signals to obtain a resolving angular position theta _ RDC, the resolving angular position theta _ RDC is transmitted to the servo controller, and a resolving angular speed Vel _ RDC is obtained through calculation; the servo controller calculates and outputs control current to the servo motor according to the difference between the command angular velocity Vel _ zl output by the error representation unit and the resolving angular velocity Vel _ RDC; the servo motor outputs torque to drive a load to track the command angular speed Vel _ zl;
2. amplitude correction unit
As shown in fig. 2, the amplitude correction unit includes a voltage follower and a forward amplifier; the angle correction device is used for correcting angle resolving errors caused by inconsistent amplitudes of sine winding output signals sig _ sin and cosine winding output signals sig _ cos;
if the cosine winding output signal sig _ cos is taken as a reference, the sine winding output signal sig _ sin of the rotary transformer is transmitted to a voltage follower, output impedance is improved, a subsequent sine winding output signal sig _ sin _ f1 is obtained and then output to a forward amplifier, the subsequent sine winding output signal sig _ sin _ f1 is amplified or reduced according to a second harmonic error amplitude Amp output by an error characterization unit, and an amplitude correction sine signal sig _ sin _ c1 and an amplitude correction cosine signal sig _ cos _ c1 are obtained and output to a phase angle correction unit;
if the sine winding output signal sig _ sin is taken as a reference, the cosine winding output signal sig _ cos of the rotary transformer is transmitted to the voltage follower, the output impedance is improved, the subsequent cosine winding output signal sig _ cos _ f1 is obtained and then output to the forward amplifier, the subsequent cosine winding output signal sig _ cos _ f1 is amplified or reduced according to the second harmonic error amplitude Amp output by the error characterization unit, and an amplitude correction cosine signal sig _ sin _ c1 and an amplitude correction cosine signal sig _ cos _ c1 are obtained and output to the phase angle correction unit.
3. Phase angle correction unit
As shown in fig. 3, the phase angle correction unit includes a voltage follower, a forward amplifier, and a bidirectional adder; the phase angle correction unit is used for correcting an angle resolving error caused by non-ideal orthogonality of the sine winding output signal sig _ sin and the cosine winding output signal sig _ cos;
if the cosine winding output signal sig _ cos is taken as a reference, the amplitude correction sine signal sig _ sin _ c1 is output to a voltage follower, output impedance is improved, a subsequent sine winding output signal sig _ sin _ f2 is obtained and then output to a forward amplifier, the subsequent sine winding output signal sig _ sin _ f2 is amplified or reduced according to a second harmonic error amplitude Amp output by an error characterization unit to obtain a phase angle error correction value sig _ sin _ e, the phase angle error correction value sig _ sin _ e is output to a bidirectional adder, and the bidirectional adder carries out addition and subtraction processing on the amplitude correction cosine signal sig _ cos _ c1 according to the second harmonic error amplitude Amp output by the error characterization unit to obtain a phase angle correction sine signal sig _ sin _ c2 and a phase angle correction cosine signal sig _ cos _ c2 and outputs to a rotary transformer demodulator;
if the sine winding output signal sig _ sin is taken as a reference, the amplitude correction cosine signal sig _ cos _ c1 is output to a voltage follower, output impedance is improved, a subsequent cosine winding output signal sig _ cos _ f2 is obtained and then output to a forward amplifier, the subsequent cosine winding output signal sig _ cos _ f2 is amplified or reduced according to a second harmonic error amplitude Amp output by an error characterization unit, a phase angle error correction value sig _ cos _ e is obtained and output to a bidirectional adder, and the bidirectional adder carries out addition and subtraction processing on the amplitude correction sine signal sig _ sin _ c1 according to the second harmonic error amplitude Amp output by the error characterization unit, so that a phase angle correction sine signal sig _ sin _ c2 and a phase angle correction cosine signal sig _ cos _ c2 are obtained and output to a rotary transformer demodulator.
As shown in fig. 5, the adjustment method for the forward amplifier in the amplitude correction unit, the forward amplifier in the phase angle correction unit, and the bidirectional adder is as follows according to the magnitude of the second harmonic error amplitude Amp:
step 2, judging whether the second harmonic error amplitude Amp is smaller: if yes, continuing to reduce the amplification ratio of the forward amplifier of the amplitude correction unit; if not, adjusting the amplification ratio of the forward amplifier of the phase angle correction unit to a minimum value a (a is less than 1/1000), setting the bidirectional adder of the phase angle correction unit as an adder, and judging whether the amplitude of the second harmonic error amplitude Amp is reduced: if yes, increasing the amplification ratio of a positive amplifier of the phase angle correction unit, and entering step 3; if not, setting the bidirectional adder of the phase angle correction unit as a subtracter, and entering the step 4;
step 3, judging whether the second harmonic error amplitude Amp is smaller: if yes, continuously increasing the amplification ratio of the phase angle correction unit forward amplifier; if not, the method ends;
step 4, judging whether the second harmonic error amplitude Amp is smaller, if so, continuing to increase the amplification ratio of the phase angle correction unit forward amplifier; if not, the method ends.
4. Rotation error characterization unit
As shown in fig. 4, the rotation error characterization unit sends an instruction angular velocity to the servo controller and receives a resolving angular velocity of the servo controller, and performs a spectrum analysis on the resolving angular velocity, and uses a second harmonic amplitude to characterize the rotation error, where the second harmonic amplitude is an amplitude Amp at a second frequency Frq of the rotation speed in the spectrum analysis result. The second harmonic amplitude Amp is transmitted to the amplitude correction unit and the phase angle correction unit by the revolution change error characterization unit to serve as a basis for adjusting the amplitude correction unit and the phase angle correction unit.
A hardware self-correcting method for angle measurement errors of a rotary transformer comprises the following steps:
step one, sending an instruction angular velocity to a servo controller through an error characterization unit, and controlling a servo motor to drive a load to rotate at the instruction angular velocity through the servo controller;
the rotary transformer induces a sine winding output signal sig _ sin and a cosine winding output signal sig _ cos related to a load angular position theta according to an excitation signal sig _ jl output by the rotary transformer demodulator, and sends the signals to the amplitude correction unit and the phase angle correction unit;
carrying out spectrum analysis on the resolving angular velocity sent by the servo controller through an error characterization unit, and transmitting a second harmonic amplitude Amp in an analysis result to an amplitude correction unit and a phase angle correction unit;
secondly, the amplitude correction unit and the phase angle correction unit respectively adjust the amplitude and the phase difference of the sine winding output signal sig _ sin and the cosine winding output signal sig _ cos according to the amplitude of the second harmonic amplitude Amp to obtain a sine winding correction output signal sig _ sin _ c2 and a cosine winding correction output signal sig _ cos _ c2 which are transmitted to the resolver demodulator;
thirdly, demodulating the sine winding correction output signal sig _ sin _ c2 and the cosine winding correction output signal sig _ cos _ c2 by the rotary transformer demodulator to obtain a resolving angular position theta _ RDC, and transmitting the resolving angular position theta _ RDC to the servo controller;
and step four, calculating by the servo controller to obtain a resolved angular velocity Vel _ RDC, calculating according to the difference between the command angular velocity Vel _ zl and the resolved angular velocity Vel _ RDC, outputting a control current to the servo motor, and returning to the step one.
Although the present invention has been described with reference to the preferred embodiments, it is not intended to limit the present invention, and those skilled in the art can make variations and modifications of the present invention without departing from the spirit and scope of the present invention by using the methods and technical contents disclosed above.
Parts of the invention not described in detail are well known to the person skilled in the art.
Claims (9)
1. A hardware self-correction system for rotary transformer angle measurement errors is characterized by comprising: the device comprises a servo control unit, an amplitude correction unit, a phase angle correction unit and an error characterization unit;
the servo control unit comprises a servo controller, a servo motor, a load, a rotary transformer and a rotary transformer demodulator; the rotary transformer is installed on a load, the rotary transformer demodulator outputs an excitation signal sig _ jl to the rotary transformer, the rotary transformer induces a sine winding output signal sig _ sin and a cosine winding output signal sig _ cos which are related to a load angular position theta, and the sine winding output signal sig _ sin and the cosine winding output signal sig _ cos pass through an amplitude correction unit and a phase angle correction unit to obtain a sine winding correction output signal sig _ sin _ c2 and a cosine winding correction output signal sig _ cos _ c2 which are transmitted to the rotary transformer demodulator; the rotary-transformer demodulator demodulates the sine-winding correction output signal sig _ sin _ c2 and the cosine-winding correction output signal sig _ cos _ c2 to obtain a resolving angular position theta _ RDC, transmits the resolving angular position theta _ RDC to the servo controller, and calculates to obtain a resolving angular velocity Vel _ RDC; the servo controller calculates and outputs control current to the servo motor according to the difference between the command angular velocity Vel _ zl output by the error representation unit and the resolving angular velocity Vel _ RDC; the servo motor outputs torque to drive a load to track the command angular speed Vel _ zl;
the amplitude correction unit adjusts the amplitude of sine and cosine winding output signals output by the rotary transformer and eliminates amplitude errors; the phase angle correction unit adjusts the phase difference of sine and cosine winding output signals output by the amplitude correction unit and eliminates orthogonal errors;
the rotation variation error characterization unit sends an instruction angular speed to the control servo controller, receives the resolving angular speed of the servo controller, performs frequency spectrum analysis on the resolving angular speed to obtain a second harmonic amplitude as the rotation variation error, and transmits the second harmonic amplitude Amp to the amplitude correction unit and the phase angle correction unit as the basis for adjusting the amplitude correction unit and the phase angle correction unit;
the amplitude correction unit comprises a voltage follower and a forward amplifier and is used for correcting an angle resolving error caused by the inconsistency of amplitudes of the sine winding output signal sig _ sin and the cosine winding output signal sig _ cos;
if the cosine winding output signal sig _ cos is taken as a reference, the sine winding output signal sig _ sin is transmitted to a voltage follower, output impedance is improved, a subsequent sine winding output signal sig _ sin _ f1 is obtained and then output to a forward amplifier, the subsequent sine winding output signal sig _ sin _ f1 is amplified or reduced according to a second harmonic error amplitude Amp output by an error characterization unit, and an amplitude correction sine signal sig _ sin _ c1 and an amplitude correction cosine signal sig _ cos _ c1 are obtained and output to a phase angle correction unit;
if the sine winding output signal sig _ sin is taken as a reference, the cosine winding output signal sig _ cos is transmitted to a voltage follower, output impedance is improved, a subsequent cosine winding output signal sig _ cos _ f1 is obtained and then output to a forward amplifier, the subsequent cosine winding output signal sig _ cos _ f1 is amplified or reduced according to a second harmonic error amplitude Amp output by an error characterization unit, and an amplitude correction cosine signal sig _ sin _ c1 and an amplitude correction cosine signal sig _ cos _ c1 are obtained and output to a phase angle correction unit.
2. The hardware self-correction system for angle measurement error of rotary transformer according to claim 1, wherein: the phase angle correction unit comprises a voltage follower, a forward amplifier and a bidirectional adder; the phase angle correction unit corrects an angle resolving error caused by non-ideal orthogonality of a sine winding output signal sig _ sin and a cosine winding output signal sig _ cos;
if the cosine winding output signal sig _ cos is taken as a reference, outputting an amplitude correction sine signal sig _ sin _ c1 to a voltage follower, improving output impedance to obtain a subsequent sine winding output signal sig _ sin _ f2, then outputting the signal to a forward amplifier, amplifying or reducing the subsequent sine winding output signal sig _ sin _ f2 according to a second harmonic error amplitude Amp output by an error characterization unit to obtain a phase angle error correction value sig _ sin _ e, and outputting the phase angle error correction value sig _ sin _ e to a bidirectional adder; the bidirectional adder carries out addition and subtraction of a phase angle error correction quantity sig _ sin _ e on the amplitude correction cosine signal sig _ cos _ c1 according to the second harmonic error amplitude Amp output by the error characterization unit to obtain a phase angle correction sine signal sig _ sin _ c2 and a phase angle correction cosine signal sig _ cos _ c2, and outputs the phase angle correction sine signal sig _ sin _ c 3526 to the resolver;
if the sine winding output signal sig _ sin is taken as a reference, the amplitude correction cosine signal sig _ cos _ c1 is output to a voltage follower, output impedance is improved, a subsequent cosine winding output signal sig _ cos _ f2 is obtained and then output to a forward amplifier, subsequent cosine winding output signal sig _ cos _ f2 is amplified or reduced according to a second harmonic error amplitude Amp output by an error characterization unit, a phase angle error correction value sig _ cos _ e is obtained and output to a bidirectional adder; the bidirectional adder carries out addition and subtraction of a phase angle error correction amount sig _ cos _ e on the amplitude correction sine signal sig _ sin _ c1 according to the second harmonic error amplitude Amp output by the error characterization unit to obtain a phase angle correction sine signal sig _ sin _ c2 and a phase angle correction cosine signal sig _ cos _ c2, and outputs the phase angle correction sine signal sig _ sin _ c2 and the phase angle correction cosine signal sig _ cos _ c2 to the resolver.
3. The hardware self-correction system for angle measurement error of rotary transformer according to claim 2, wherein: the second harmonic amplitude Amp is the amplitude at the position of the rotational speed second frequency multiplication frequency Frq in the frequency spectrum analysis result;
the rotational speed frequency Frq is the angular speed multiplied by the number of rotational pole pairs divided by 180.
4. The hardware self-correction system for angle measurement error of rotary transformer according to claim 3, wherein: according to the magnitude of the second harmonic error amplitude Amp, the adjusting method of the forward amplifier in the amplitude correction unit, the forward amplifier in the phase angle correction unit and the bidirectional adder is as follows:
step 1, increasing the amplification ratio of a forward amplifier of an amplitude correction unit, and judging whether a second harmonic error amplitude Amp is smaller: if yes, continuously increasing the amplification ratio of the forward amplifier of the amplitude correction unit; if not, reducing the amplification ratio of the forward amplifier of the amplitude correction unit, and entering the step 2;
step 2, judging whether the second harmonic error amplitude Amp is smaller: if yes, continuing to reduce the amplification ratio of the forward amplifier of the amplitude correction unit; if not, adjusting the amplification ratio of a forward amplifier of the phase angle correction unit to a minimum value a, setting a bidirectional adder of the phase angle correction unit as an adder, and judging whether the amplitude of the second harmonic error amplitude Amp is reduced: if yes, increasing the amplification ratio of a positive amplifier of the phase angle correction unit, and entering step 3; if not, setting the bidirectional adder of the phase angle correction unit as a subtracter, and entering the step 4;
step 3, judging whether the second harmonic error amplitude Amp is smaller: if yes, continuously increasing the amplification ratio of the phase angle correction unit forward amplifier; if not, the method ends;
step 4, judging whether the second harmonic error amplitude Amp is smaller, if so, continuing to increase the amplification ratio of the phase angle correction unit forward amplifier; if not, the method ends.
5. A hardware self-correcting method for rotary transformer angle measurement errors is characterized by comprising the following steps:
step one, sending an instruction angular velocity to a servo controller through an error characterization unit, and controlling a servo motor to drive a load to rotate at the instruction angular velocity through the servo controller;
the rotary transformer induces a sine winding output signal sig _ sin and a cosine winding output signal sig _ cos related to a load angular position theta according to an excitation signal sig _ jl output by the rotary transformer demodulator, and sends the signals to the amplitude correction unit and the phase angle correction unit;
carrying out spectrum analysis on the resolving angular velocity sent by the servo controller through an error characterization unit, and transmitting a second harmonic amplitude Amp in an analysis result to an amplitude correction unit and a phase angle correction unit;
secondly, the amplitude correction unit and the phase angle correction unit respectively adjust the amplitude and the phase difference of the sine winding output signal sig _ sin and the cosine winding output signal sig _ cos according to the amplitude of the second harmonic amplitude Amp to obtain a sine winding correction output signal sig _ sin _ c2 and a cosine winding correction output signal sig _ cos _ c2 which are transmitted to the resolver demodulator;
thirdly, demodulating the sine winding correction output signal sig _ sin _ c2 and the cosine winding correction output signal sig _ cos _ c2 by the rotary transformer demodulator to obtain a resolving angular position theta _ RDC, and transmitting the resolving angular position theta _ RDC to the servo controller;
and step four, calculating by the servo controller to obtain a resolved angular velocity Vel _ RDC, calculating according to the difference between the command angular velocity Vel _ zl and the resolved angular velocity Vel _ RDC, outputting a control current to the servo motor, and returning to the step one.
6. The hardware self-correction method for angle measurement error of rotary transformer according to claim 5, wherein in step two, the amplitude correction unit adjusts the amplitude of the sine winding output signal sig _ sin and the cosine winding output signal sig _ cos according to the magnitude of the second harmonic error amplitude Amp as follows:
if the cosine winding output signal sig _ cos is taken as a reference, the sine winding output signal sig _ sin is transmitted to a voltage follower, output impedance is improved, a subsequent sine winding output signal sig _ sin _ f1 is obtained and then output to a forward amplifier, the subsequent sine winding output signal sig _ sin _ f1 is amplified or reduced according to a second harmonic error amplitude Amp, an amplitude correction sine signal sig _ sin _ c1 and an amplitude correction cosine signal sig _ cos _ c1 are obtained and output to a phase angle correction unit;
if the sine winding output signal sig _ sin is taken as a reference, the cosine winding output signal sig _ cos is transmitted to a voltage follower, output impedance is improved, a subsequent cosine winding output signal sig _ cos _ f1 is obtained and then output to a forward amplifier, the subsequent cosine winding output signal sig _ cos _ f1 is amplified or reduced according to a second harmonic error amplitude Amp, and an amplitude correction cosine signal sig _ sin _ c1 and an amplitude correction cosine signal sig _ cos _ c1 are obtained and output to a phase angle correction unit.
7. The hardware self-correction method for the angle measurement error of the rotary transformer of claim 6, wherein in the second step, the phase angle correction unit adjusts the phase difference between the sine winding output signal sig _ sin and the cosine winding output signal sig _ cos according to the magnitude of the second harmonic error amplitude Amp as follows:
if the cosine winding output signal sig _ cos is taken as a reference, outputting an amplitude correction sine signal sig _ sin _ c1 to a voltage follower, improving output impedance to obtain a subsequent sine winding output signal sig _ sin _ f2, then outputting the signal to a forward amplifier, amplifying or reducing the subsequent sine winding output signal sig _ sin _ f2 according to a second harmonic error amplitude Amp to obtain a phase angle error correction value sig _ sin _ e, and outputting the phase angle error correction value sig _ sin _ e to a bidirectional adder; the bidirectional adder carries out addition and subtraction of a phase angle error correction amount sig _ sin _ e on the amplitude correction cosine signal sig _ cos _ c1 according to the second harmonic error amplitude Amp to obtain a phase angle correction sine signal sig _ sin _ c2 and a phase angle correction cosine signal sig _ cos _ c2, and outputs the phase angle correction sine signal sig _ sin _ c 3526 to the resolver demodulator;
if the sine winding output signal sig _ sin is taken as a reference, outputting an amplitude correction cosine signal sig _ cos _ c1 to a voltage follower, improving output impedance to obtain a subsequent cosine winding output signal sig _ cos _ f2, then outputting to a forward amplifier, amplifying or reducing the subsequent cosine winding output signal sig _ cos _ f2 according to a second harmonic error amplitude Amp to obtain a phase angle error correction value sig _ cos _ e, and outputting to a bidirectional adder; the bidirectional adder carries out addition and subtraction of a phase angle error correction amount sig _ cos _ e on the amplitude correction sine signal sig _ sin _ c1 according to the second harmonic error amplitude Amp to obtain a phase angle correction sine signal sig _ sin _ c2 and a phase angle correction cosine signal sig _ cos _ c2, and outputs the phase angle correction sine signal sig _ sin _ c 3526 to the resolver demodulator.
8. The hardware self-correction method for angle measurement error of rotary transformer according to claim 7, wherein in step two, according to the magnitude of the second harmonic error amplitude Amp, the adjustment method for the forward amplifier in the amplitude correction unit, the forward amplifier in the phase angle correction unit and the bidirectional adder is as follows:
step 1, increasing the amplification ratio of a forward amplifier of an amplitude correction unit, and judging whether a second harmonic error amplitude Amp is smaller: if yes, continuously increasing the amplification ratio of the forward amplifier of the amplitude correction unit; if not, reducing the amplification ratio of the forward amplifier of the amplitude correction unit, and entering the step 2;
step 2, judging whether the second harmonic error amplitude Amp is smaller: if yes, continuing to reduce the amplification ratio of the forward amplifier of the amplitude correction unit; if not, adjusting the amplification ratio of a forward amplifier of the phase angle correction unit to a minimum value a, setting a bidirectional adder of the phase angle correction unit as an adder, and judging whether the amplitude of the second harmonic error amplitude Amp is reduced: if yes, increasing the amplification ratio of a positive amplifier of the phase angle correction unit, and entering step 3; if not, setting the bidirectional adder of the phase angle correction unit as a subtracter, and entering the step 4;
step 3, judging whether the second harmonic error amplitude Amp is smaller: if yes, continuously increasing the amplification ratio of the phase angle correction unit forward amplifier; if not, the method ends;
step 4, judging whether the second harmonic error amplitude Amp is smaller, if so, continuing to increase the amplification ratio of the phase angle correction unit forward amplifier; if not, the method ends.
9. The resolver angle measurement error hardware self-correction method according to claim 8, wherein a is less than 1/1000.
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