CN1655444A - Theta angle iteration compensation method in linear motor vector control - Google Patents

Abstract

This invention relates to line motor vector control theta iterate compensation method, which belongs to line motor servo movement control method and mainly applied in permanent line motor servo control field. The method comprises the following steps: estimating the real value of theta angle and stabling identification formula; getting n times of theta angle estimation value to compute the above formula after dispersion according to the identification formula. The invention compares the estimation value with the real measured value through repeated iterated compensation to make the theta orderly near the real time.

Description

Theta angle iteration compensation method in the linear electric motors vector control

Technical field

The invention belongs to linear electric motors servo motion control method, be specifically related to the theta angle iteration compensation method in a kind of linear electric motors vector control, be mainly used in permanent-magnetism linear motor SERVO CONTROL field.

Background technology

Along with development of advanced manufacturing such as precision manufacturing and numerical controls, at a high speed, efficiently, high accuracy becomes the developing direction of today's numerical control lathe, long-stroke permanent magnet formula linear electric motors are because advantages such as its big stroke, high accuracy, high acceleration and high thrust are occupied unique status in high-accuracy processing.In the linear electric motors decoupling zero vector control, position angle (θ angle) is meant the space angle θ of rotor magnetic pole with respect to α axis under the alpha-beta coordinate system, as shown in Figure 1.At present, mainly be by measuring its position, calculate then and try to achieve the θ angle, for example described in the article " the linear AC motor transform vector is controlled soft commutation method and realization " that BJ University of Aeronautics ﹠ Astronautics's journal 2004 (4) is delivered, its θ angle is tried to achieve by measuring to calculate behind its position, does not compensate.But, because the manufacturing defect of linear electric motors or the pulse missing in the position probing process, because control system defective etc. all can cause the θ angle detection of linear electric motors control system deviation appears perhaps, this deviation has seriously influenced the control performance of linear electric motors when high-speed, high precision is controlled, occur out-of-control phenomenon when serious.

Summary of the invention

The present invention proposes the theta angle iteration compensation method in a kind of linear electric motors vector control, is used for solving in the linear electric motors vector control θ angular displacement problem of the linear electric motors control system that causes because linear electric motors body defects and control system are made mistakes.

Theta angle iteration compensation method in the linear electric motors vector control of the present invention is used for the identification and the correction at vector decoupling zero control θ angle, the steps include:

(1) according to the identification formula of θ angle, the estimated value computing formula that gets the n time θ angle after the discretization is:

$\widehat{\mathrm{\θ}}\left(n\right)={\mathrm{\θ}}^{\′}(n-1)+T_2\widehat{\mathrm{\ω}}\left(n\right)=\mathrm{\θ}(n-1)+\mathrm{\Δ\θ}(n-1)+T_2\widehat{\mathrm{\ω}}\left(n\right)$

$\widehat{\mathrm{\ω}}\left(n\right)=(k_1{T}_1+k_2)[i_d\left(n\right)\widehat{i_q}\left(n\right)-i_q\left(n\right)\widehat{i_d}\left(n\right)-\frac{{\mathrm{\ψ}}_r}{L}(i_q\left(n\right)-\widehat{i_q}\left(n\right))]$

$-k_2[i_d(n-1)\widehat{i_q}(n-1)-i_q(n-1)\widehat{i_d}(n-1)-\frac{{\mathrm{\ψ}}_r}{L}(i_q(n-1)-\widehat{i_q}(n-1))]+\mathrm{\ω}(n-1)$

Wherein

Be the equivalent angular speed estimated value measured for the n time,

Be the n time estimated value, k by the θ angle after the position measurement ₁, k ₂Be adjustment factor, k ₁Scope be 0.002～0.01, k ₂Scope be 0.002～0.05; Ψ _fBe the useful flux of permanent magnet, inductance, the T that L is linear electric motors ₁Sampling time, T for electric current loop ₂For sampling time, the ω (n) of speed ring is that equivalent angular velocity measurement value, the θ (n) that measures for the n time is the n time measured value, i by the θ angle after the position measurement _dBe exciting current, i _qFor torque current, ω be motor the angular speed equivalent, For the exciting current estimated value,

Be the torque current estimated value;

(2) according to the compensation that iterates of the computing formula of step (1), thereby θ is contended time near actual value, gained is dynamic

The vector control that promptly is used for motion control.

Theta angle iteration compensation method in the described linear electric motors vector control is characterized in that: the 0th the compensation rate Δ θ (0)=0 of θ angle value, the estimated value that can get the 1st θ angle is $\widehat{\mathrm{\θ}}\left(1\right)=\mathrm{\θ}\left(0\right)+T_2\widehat{\mathrm{\ω}}\left(1\right),$ Wherein Value is its measured value ω (1), θ (0) be the 0th time by calculating angle value after the position measurement, the computational methods of θ angle are

$\mathrm{\θ}=\mathrm{mod}\left(\frac{p}{d}\right)*\left(2\mathrm{\π}\right)$

Wherein, p is the displacement that displacement transducer detects, and d is the pole span of linear electric motors, and mod is a modulo operation; Be the estimated value of last θ angle of proofreading and correct for the first time, be used for the vector control of motion control.

Innovation part of the present invention is:

(1) estimated value of the compensation method of θ angle employing θ angle can be eliminated the θ angular deviation problem that occurs to compensating by the measured value that calculates after the position measurement in vector control.

(2) in the process of iterating, can make the value of proofreading and correct back θ angle one by one near actual value, very big practicality is arranged.

(3) estimated value of θ angle obtains by parameter identification, only the exciting current i that obtains with the linear electric motors decoupling zero _d, torque current i _qAnd linear electric motors equivalence angular velocity omega is relevant.Above-mentioned three variablees are all the output of vector control, to θ angle correct, more can reflect the actual value of θ angle with these three amounts.

The present invention has proposed a kind of effective solution for the θ angular displacement that solves in the linear electric motors vector control, the theta angle iteration compensation method that adopts is proofreaied and correct the measure error at θ angle, can improve the control precision and the stability of system, the linearisation of electromagnetic push and mechanical traction dynamic balance and the performance of dynamic response have been improved simultaneously, from having solved the linear electric motors double vibrations problem that causes owing to angular deviation to a great extent, improved the positioning accuracy and the traveling comfort of linear electric motors, played very big facilitation for the research and development of linear electric motors control system and the practicability of linear electric motors.

Description of drawings

Fig. 1 is current phasor figure under alpha-beta and the d-q coordinate system.

Embodiment

Below formula that the present invention is adopted specify:

(1) input parameter of the compensation method of θ angle is exciting current (i in the linear electric motors vector control method _d), torque current (i _q), the angular speed equivalent (ω) of motor, exciting current estimated value

The torque current estimated value

The estimator of angular speed equivalent With by measuring the θ angle that calculates behind its position; The computational methods of θ angle are

$\mathrm{\θ}=\mathrm{mod}\left(\frac{p}{d}\right)*\left(2\mathrm{\π}\right)$

Wherein, p is the displacement that displacement transducer detects, and d is the pole span of linear electric motors, and mod is a modulo operation.

At first will be when (2) compensating according to i _d, i _qActual value to the θ angle estimates, its estimated value is by carrying out obtaining after the identification to the θ angle, and its discrimination method is as follows:

$\widehat{\mathrm{\ω}}={\∫}_0^t{k}_1[i_d\widehat{i_q}-i_q\widehat{i_q}-\frac{{\mathrm{\ψ}}_r}{L}(i_q-\widehat{i_q})]d_{\mathrm{\τ}}+k_2[i_d\widehat{i_q}-i_q\widehat{i_d}-\frac{{\mathrm{\ψ}}_r}{L}(i_q-\widehat{i_q})]+\widehat{\mathrm{\ω}}\left(0\right)$

$\widehat{\mathrm{\θ}}={\∫}_0^t\widehat{\mathrm{\ω}}{d}_{\mathrm{\τ}}+\widehat{\mathrm{\θ}}\left(0\right)$

Wherein, k ₁, k ₂Be adjustment factor,

Initial angle speed equivalent, symbol ^ represents estimated value,

Be the estimated value of θ angle, Ψ _fBe the useful flux of permanent magnet, L is the inductance of linear electric motors.

(3) the concrete compensation process of the iteration compensation method of θ angle is:

According to the identification formula of θ angle in the step (2), the estimated value computing formula that gets the n time θ angle after the discretization is

$\widehat{\mathrm{\ω}}\left(n\right)=(k_1{T}_1+k_2)[i_d\left(n\right)\widehat{i_q}\left(n\right)-i_q\left(n\right)\widehat{i_d}\left(n\right)-\frac{{\mathrm{\ψ}}_r}{L}(i_q\left(n\right)-\widehat{i_q}\left(n\right))]$

$-k_2[i_d(n-1)\widehat{i_q}(n-1)-i_q(n-1)\widehat{i_d}(n-1)-\frac{{\mathrm{\ψ}}_r}{L}(i_q(n-1)-\widehat{i_q}(n-1))]+\widehat{\mathrm{\ω}}(n-1)$

$\widehat{\mathrm{\θ}}\left(n\right)={\mathrm{\θ}}^{\′}(n-1)+T_2\widehat{\mathrm{\ω}}\left(n\right)=\mathrm{\θ}(n-1)+\mathrm{\Δ\θ}(n-1)+T_2\widehat{\mathrm{\ω}}\left(n\right)$

Make last equivalent angular speed

The estimated value value be measured value ω (n-1), then can get

$\widehat{\mathrm{\ω}}\left(n\right)=(k_1{T}_1+k_2)[i_d\left(n\right)\widehat{i_q}\left(n\right)-i_q\left(n\right)\widehat{i_d}\left(n\right)-\frac{{\mathrm{\ψ}}_r}{L}(i_q\left(n\right)-\widehat{i_q}\left(n\right))]$

$-k_2[i_d(n-1)\widehat{i_q}(n-1)-i_q(n-1)\widehat{i_d}(n-1)-\frac{{\mathrm{\ψ}}_r}{L}(i_q(n-1)-\widehat{i_q}(n-1))]+\mathrm{\ω}(n-1)$

T ₁Be the sampling time of electric current loop, T ₂Be the sampling time of speed ring,

And ω (n) is respectively equivalent angular speed estimated value and the measured value of measuring for the n time,

And θ (n) is respectively estimated value and the measured value by the θ angle after the position measurement the n time, and makes the 0th the compensation rate Δ θ (0)=0 of θ angle value, and the estimated value that can get the 1st θ angle is

$\widehat{\mathrm{\θ}}\left(1\right)=\mathrm{\θ}\left(0\right)+T_2\widehat{\mathrm{\ω}}\left(1\right)$

Wherein,

Value is its measured value ω (1), θ (0) be the 0th time by calculating angle value after the position measurement,

Be the estimated value of last θ angle of proofreading and correct for the first time, be used for the vector control of motion control.

The rest may be inferred, and the n time compensation rate of θ angle value is

$\mathrm{\Δ\θ}\left(n\right)=\widehat{\mathrm{\θ}}\left(n\right)-\mathrm{\θ}\left(n\right)$

With after the estimated value computing formula of the n time θ angle combines as can be seen, preceding n-1 time compensation rate has added up in this error amount.Thereby the value of the n-1 time compensation back θ angle is

θ’(n-1)＝θ(n-1)+Δθ(n-1)

According to the identification formula of θ angle in the step (2), the estimated value that gets the n time θ angle after the discretization is

$\widehat{\mathrm{\θ}}\left(n\right)={\mathrm{\θ}}^{\′}(n-1)+T_2\widehat{\mathrm{\ω}}\left(n\right)=\mathrm{\θ}(n-1)+\mathrm{\Δ\θ}(n-1)+T_2\widehat{\mathrm{\ω}}\left(n\right)$

Be estimated value, be used for the vector control of motion control through θ angle behind the iteration correction.

Claims (2)

1. the theta angle iteration compensation method in the linear electric motors vector control is used for the identification and the correction at vector decoupling zero control θ angle, the steps include:

(1) according to the identification formula of θ angle, the estimated value computing formula that gets the n time θ angle after the discretization is:

$\widehat{\mathrm{\θ}}\left(n\right)={\mathrm{\θ}}^{\′}(n-1)+T_2\widehat{\mathrm{\ω}}\left(n\right)=\mathrm{\θ}(n-1)+\mathrm{\Δ\θ}(n-1)+T_2\widehat{\mathrm{\ω}}\left(n\right)$

$\widehat{\mathrm{\ω}}\left(n\right)=(k_1{T}_1+k_2)[i_d\left(n\right){\hat{i}}_q\left(n\right)-i_q\left(n\right){\hat{i}}_d\left(n\right)-\frac{{\mathrm{\ψ}}_r}{L}(i_q\left(n\right)-{\hat{i}}_q\left(n\right))]$

${-k}_2[i_d(n-1){\hat{i}}_q(n-1)-i_q(n-1){\hat{i}}_d(n-1)-\frac{{\mathrm{\ψ}}_r}{L}(i_q(n-1)-{\hat{i}}_q(n-1))]+\mathrm{\ω}(n-1)$

Wherein

Be the equivalent angular speed estimated value measured for the n time,

Be the n time estimated value, k by the θ angle after the position measurement ₁, k ₂Be adjustment factor, k ₁Scope be 0.002～0.01, k ₂Scope be 0.002～0.05; ψ _fBe the useful flux of permanent magnet, inductance, the T that L is linear electric motors ₁Sampling time, T for electric current loop ₂For sampling time, the ω (n) of speed ring is that equivalent angular velocity measurement value, the θ (n) that measures for the n time is the n time measured value, i by the θ angle after the position measurement _dBe exciting current, i _qFor torque current, ω be motor the angular speed equivalent,

For the exciting current estimated value,

Be the torque current estimated value;

(2) according to the compensation that iterates of the computing formula of step (1), thereby θ is contended time near actual value, gained is dynamic The vector control that promptly is used for motion control.

2. the theta angle iteration compensation method in the linear electric motors vector control as claimed in claim 1 is characterized in that: the 0th the compensation rate Δ θ (0)=0 of θ angle value, the estimated value that can get the 1st θ angle is $\widehat{\mathrm{\θ}}\left(1\right)=\mathrm{\θ}\left(0\right)+T_2\widehat{\mathrm{\ω}}\left(1\right),$ Wherein Value is its measured value ω (1), θ (0) be the 0th time by calculating angle value after the position measurement, the computational methods of θ angle are

$\mathrm{\θ}=\mathrm{mod}\left(\frac{p}{d}\right)*\left(2\mathrm{\π}\right)$

Wherein, p is the displacement that displacement transducer detects, and d is the pole span of linear electric motors, and mod is a modulo operation; Be the estimated value of last θ angle of proofreading and correct for the first time, be used for the vector control of motion control.

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