阅读说明：本技术 一种降低开关方式驱动音圈电机迟滞误差的颤振方法 (Flutter method for reducing hysteresis error of voice coil motor driven in switching mode ) 是由 郭会军 林遂芳 于 2021-06-29 设计创作，主要内容包括：本发明公开了一种降低开关方式驱动音圈电机迟滞误差的颤振方法,具体按照以下步骤实施：步骤1、计算单极性调制方式下音圈电机输出平均电流；步骤2、利用步骤1得到的单极性调制方式下音圈电机输出平均电流,对占空比生成算法叠加正弦形式颤振脉宽；步骤3、利用步骤2所设计的叠加了正弦形式颤振的脉宽调制占空比生成算法控制音圈电机,完成颤振调节。解决了现有技术中存在的消除和补偿音圈电机迟滞特性需要数学建模,过程繁琐的问题。(The invention discloses a flutter method for reducing hysteresis error of a voice coil motor driven by a switching mode, which is implemented according to the following steps: step 1, calculating the average current output by a voice coil motor in a unipolar modulation mode; step 2, outputting average current by using the voice coil motor under the unipolar modulation mode obtained in the step 1, and superposing sinusoidal flutter pulse width on a duty ratio generation algorithm; and 3, controlling the voice coil motor by using the pulse width modulation duty ratio generation algorithm superposed with the sine-form flutter and designed in the step 2 to finish flutter regulation. The problem of among the prior art eliminate and compensate voice coil motor hysteresis characteristic need mathematical modeling, the process is loaded down with trivial details is solved.)

1. A flutter method for reducing hysteresis error of a voice coil motor driven by a switching mode is characterized by comprising the following steps:

step 1, calculating the average current output by a voice coil motor in a unipolar modulation mode;

step 2, outputting average current by using the voice coil motor under the unipolar modulation mode obtained in the step 1, and superposing sinusoidal flutter pulse width on a duty ratio generation algorithm;

and 3, controlling the voice coil motor by using the pulse width modulation duty ratio generation algorithm superposed with the sine-form flutter and designed in the step 2 to finish flutter regulation.

2. The chattering method for reducing the hysteresis error of a voice coil motor driven in a switching mode according to claim 1, wherein in the driving circuit of the voice coil motor in the unipolar modulation mode in step 1, the input power voltage of the driving circuit is a positive voltage + U and a negative voltage-U; switch tube T₁And a freewheeling diode D₁Form an upper bridge arm and a switch tube T₂And a freewheeling diode D₂The pulse width modulation driving signals of the bridge arms are PWM1 and PWM2 respectively, the PWM1 controls the on and off of the upper bridge arm, the PWM2 controls the on and off of the lower bridge arm, and the switch tube T is switched on when the lower bridge arm works in the forward direction₁Freewheel diode D₂And a load to form a voltage reduction circuit, and T is in reverse operation₂Freewheel diode D₂And the load form a voltage reduction circuit; tone represented by resistor R and inductor L in seriesThe equivalent model of the ring motor, namely the load, is connected between the midpoint of the two bridge arms and the ground.

3. The chattering method for reducing hysteresis error of a switching mode driving voice coil motor according to claim 2, wherein the step 1 is implemented as follows:

when the circuit enters steady state and T₁T is more than or equal to 0 and less than or equal to DT when the current is set as i₁From kirchhoff's voltage law:

wherein, U is voltage, R is equivalent resistance of the voice coil motor coil, and L is equivalent inductance of the voice coil motor coil;

let the initial value of current at this stage be I₁₀Definition ofSolving the above differential equation yields:

in the formula, e is the base number of the natural logarithm, and t is a time variable;

when T is₁At turn-off, D₂Is turned on when the current is i₂From kirchhoff's voltage law:

the initial value of the current obtained at this stage is I₂₀Solving the above equation can yield:

in the formula, t_onIs a switch tube T₁The on-time (t) is the time when the PWM wave is at high level, t is a time variable and t is more than or equal to t_on；

Because the circuit is in steady state, it is known that:

I₁₀＝i₂(T)＝I_min，I₂₀＝i₁(DT)＝I_max (5)

in the formula I_minIs the minimum value of the load current, I_maxIs the maximum value of the load current;

then, from the above equation:

in the formula, t₁DT is a switch tube T₁The end point of conduction of (1);

the average of the output current over a period can be approximated as:

in the formula, D is a duty ratio, T is a period of the PWM wave, and formula (8) is an average value of the output current of the voice coil motor.

4. The chattering method for reducing hysteresis error of a switching mode driving voice coil motor according to claim 3, wherein the step 2 is implemented as follows:

defining the flutter signal modulation ratio:

obviously rho epsilon [0,1], the dither additional current in sinusoidal form is:

wherein the parameter omega is 2 pi/T₂Period T of₂＝(20～100)T₁The positive integer k belongs to N; i is_d0The current is the current when no flutter is added;

the final current is:

in the formula I_diA dither additional current of sinusoidal form shown in formula (10);

the taylor series approximation for equation (6) can be obtained:

from equation (8):

the formula shows that:

in the formula, D_kThe duty ratio corresponding to the load current after superimposing the dither current shown in equation (11).

Substituting equation (11) can result in

D_k＝D+pDsin(ωT₁k)/2 (15)

Where rho is [0,1]]For the dither signal modulation ratio, D is the original duty cycle, D_kThe duty ratio is corresponding to the current containing the flutter.

5. The flutter method for reducing the hysteresis error of the switching mode driving voice coil motor according to claim 4, wherein the step 3 is specifically to generate a corresponding pulse width modulation waveform, i.e. PWM1 or PWM2, by using a duty ratio generation algorithm shown in formula (15), so as to control the switching tube T1 or T2 to be turned on and off, thereby completing the control of the voice coil motor.

Technical Field

The invention belongs to the technical field of voice coil motor control, and relates to a flutter method for reducing hysteresis errors of a voice coil motor driven in a switching mode.

Background

The voice coil motor is a special type of dc linear motor manufactured based on the lorentz force principle, i.e. an energized coil generates a driving force in a magnetic field, the magnitude of the force being proportional to the current applied to the coil. The voice coil motor driven by the switching mode, namely the pulse width modulation technology, has the advantages of quick response, no lag, good force characteristic, high efficiency, simple interface, interference resistance and the like, and is widely applied to systems such as semiconductor lithography equipment, precision machine tools, optical electron microscopes, laser communication and the like.

The response time of the voice coil motor in the switching mode is shortened, the positioning precision is improved, and the production efficiency and the benefit are improved. However, when the voice coil motor works in a high-frequency, high-speed and high-acceleration mode, a very significant non-monotonic complex hysteresis characteristic is shown, that is, a non-linear relationship exists between input voltage and output displacement, so that a positioning error is caused, and the positioning accuracy of the voice coil motor is seriously influenced. Therefore, analyzing and compensating the hysteresis characteristics of the voice coil motor becomes a key research point at home and abroad.

The hysteresis characteristics of the voice coil motor have many factors, including residual magnetic field, non-uniform magnetic field, friction force, gravitational field, etc. In order to eliminate or compensate the hysteresis characteristic of the voice coil motor, the processing and assembling process level can be improved as much as possible when the voice coil motor is manufactured, but the hysteresis is improved by adopting a control method. The currently adopted control methods include model-based feedforward control, high-gain feedback control and charge amplifier. Among them, the model-based feedforward control is very complicated in modeling, although it can effectively eliminate the hysteresis characteristic. The high-gain feedback control reduces the hysteresis characteristic by means of the trap, but the characteristic is severely degraded when the model parameter changes or the external environment changes. The charge amplifier is easy to realize, but the bias voltage link arranged in the circuit seriously influences the control performance.

Disclosure of Invention

The invention aims to provide a flutter method for reducing hysteresis errors of a voice coil motor driven in a switching mode, and solves the problems that in the prior art, mathematical modeling is needed for eliminating and compensating hysteresis characteristics of the voice coil motor, and the process is complicated.

The technical scheme adopted by the invention is that the flutter method for reducing the hysteresis error of the voice coil motor driven by a switching mode is implemented according to the following steps:

step 1, calculating the average current output by a voice coil motor in a unipolar modulation mode;

step 2, outputting average current by using the voice coil motor under the unipolar modulation mode obtained in the step 1, and superposing sinusoidal flutter pulse width on a duty ratio generation algorithm;

and 3, controlling the voice coil motor by using the pulse width modulation duty ratio generation algorithm superposed with the sine-form flutter and designed in the step 2 to finish flutter regulation.

The invention is also characterized in that:

in a driving circuit of the voice coil motor in a single-polarity modulation mode in the step 1, the input power supply voltage of the driving circuit is positive voltage + U and negative voltage-U; switch tube T₁And a freewheeling diode D₁Form an upper bridge arm and a switch tube T₂And a freewheeling diode D₂The pulse width modulation driving signals of the bridge arms are PWM1 and PWM2 respectively, the PWM1 controls the on and off of the upper bridge arm, the PWM2 controls the on and off of the lower bridge arm, and the switch tube T is switched on when the lower bridge arm works in the forward direction₁Freewheel diode D₂And a load to form a voltage reduction circuit, and T is in reverse operation₂Freewheel diode D₂And the load form a voltage reduction circuit; and a voice coil motor equivalent model represented by the series connection of the resistor R and the inductor L, namely a load, is connected between the midpoint of the two bridge arms and the ground.

Step 1 is specifically carried out as follows:

when the circuit enters steady state and T₁T is more than or equal to 0 and less than or equal to DT when the current is set as i₁From kirchhoff's voltage law:

wherein, U is voltage, R is equivalent resistance of the voice coil motor coil, and L is equivalent inductance of the voice coil motor coil;

let the initial value of current at this stage be I₁₀Definition ofSolving the above differential equation yields:

in the formula, e is the base number of the natural logarithm, and t is a time variable;

when T is₁At turn-off, D₂On, let the current be i₂From kirchhoff's voltage law:

the initial value of the current obtained at this stage is I₂₀Solving the above equation can yield:

in the formula, t_onIs a switch tube T₁The on-time (t) is the time when the PWM wave is at high level, t is a time variable and t is more than or equal to t_on；

Because the circuit is in steady state, it is known that:

I₁₀＝i₂(T)＝I_min，I₂₀＝i₁(DT)＝I_max (5)

in the formula i₂(T) is a current i₂Value at time T, i₁(DT) is a current i₁Value at time DT, I_minIs the minimum value of the load current, I_maxIs the maximum value of the load current;

then, from the above equation:

in the formula, t₁DT is a switch tube T₁The end point of conduction of (1);

the average of the output current over a period can be approximated as:

in the formula, D is a duty ratio, T is a period of the PWM wave, and formula (8) is an average value of the output current of the voice coil motor.

Step 2 is specifically carried out as follows:

defining the flutter signal modulation ratio:

obviously rho epsilon [0,1], the dither additional current in sinusoidal form is:

wherein the parameter omega is 2 pi/T₂Period T of₂＝(20～100)T₁The positive integer k belongs to N; i is_d0The current is the current when no flutter is added;

the final current is:

in the formula I_diA dither additional current of sinusoidal form shown in formula (10);

the taylor series approximation for equation (6) can be obtained:

from equation (8):

the formula shows that:

in the formula, D_kThe duty ratio corresponding to the load current after superimposing the dither current shown in equation (11).

Substituting equation (11) can result in

D_k＝D+pDsin(ωT₁k)/2 (15)

Where rho is [0,1]]For the dither signal modulation ratio, D is the original duty cycle, D_kThe duty ratio is corresponding to the current containing the flutter.

Step 3 specifically is to generate a corresponding pulse width modulation waveform, i.e., PWM1 or PWM2, by using a duty ratio generation algorithm shown in formula (15), so as to control the switching on and off of the switching tube T1 or T2, thereby completing the control of the voice coil motor.

The invention has the beneficial effects that: the invention discloses a flutter method for reducing hysteresis errors of a switching mode driving voice coil motor, which solves the problems that in the prior art, mathematical modeling is needed for eliminating and compensating the hysteresis characteristics of the voice coil motor, the process is complicated, and the control performance is reduced due to an external bias voltage circuit needed by a charge amplifier method, improves the response speed and improves the linearity. A small amplitude low-frequency flutter signal is superposed on a pulse width modulation output signal for driving a voice coil motor, even if the pulse width of output voltage changes in a sine rule, the average current flowing through a coil changes in a sine rule, so that static friction force is converted into sliding friction force, the response time from static to starting is shortened, the hysteresis characteristic can be obviously reduced, and the linearity is improved to a certain extent. The implementation is simple, a mathematical model of the voice coil motor hysteresis characteristic does not need to be established, and adverse effects caused by modeling errors are avoided; and a hardware circuit for driving the voice coil motor in a switching mode is not required to be changed, so that the implementation cost is reduced.

Drawings

FIG. 1 is a PWM driving circuit diagram of a current reversible voice coil motor for reducing hysteresis error of a switching mode driving voice coil motor according to a flutter method of the present invention;

FIG. 2 is a schematic diagram of the forward VCM armature voltage and current waveforms for a method of reducing hysteresis error in a switching-mode-driven VCM according to the present invention;

FIG. 3 is a schematic diagram of a current waveform without applying dither in a dither method for reducing hysteresis error of a switching-mode-driven voice coil motor according to the present invention;

FIG. 4 is a schematic diagram of a waveform of an un-dithered voltage in a dithering method for reducing hysteresis error of a switching-mode-driven voice coil motor according to the present invention;

FIG. 5 is a schematic diagram of an output voltage waveform after applying dither in a dither method for reducing hysteresis error of a switching mode driving voice coil motor according to the present invention;

FIG. 6 is a schematic diagram of a current waveform after applying dither in a dither method for reducing hysteresis error of a switching-mode-driven voice coil motor according to the present invention;

FIG. 7 is a graph illustrating voltage versus displacement hysteresis characteristics for a method of reducing hysteresis error in a switching-mode voice coil motor in accordance with the present invention;

FIG. 8 is a graph of the results of regression analysis of the original dither-free dither in a dither method for reducing hysteresis error in a switching-mode-driven voice coil motor of the present invention;

FIG. 9 is a graph of regression analysis results after applying dither in a dither method for reducing hysteresis error of a switching mode driving voice coil motor according to the present invention.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

The invention discloses a flutter method for reducing hysteresis error of a voice coil motor driven by a switching mode, which is implemented according to the following steps:

step 1, calculating the average current output by a voice coil motor in a unipolar modulation mode;

a Pulse Width Modulation (PWM) driving circuit of a unipolar modulated current reversible voice coil motor is shown in fig. 1, in which the driving voltage of the voice coil motor is ± U, T₁And T₂To switch tubes, D₁And D₂The voice coil motor is a freewheeling diode, PWM1 and PWM2 are driving signals of a switching tube respectively, and the voice coil motor is connected in series by adopting a resistor inductorThe way is equivalent. When T is₁And D₂When in work, the voice coil motor runs in the positive direction, and when T is reached₂And D₁When the voice coil motor works, the voice coil motor runs reversely.

FIG. 2 is a schematic diagram showing the voltage and current waveforms of the armature of the voice coil motor in forward operation, where D is the duty ratio, T is the switching period, and U is_oAnd I_oRespectively, voltage and current, I_min，I_maxAnd I_d0The minimum, maximum and average values of the current are respectively.

In a driving circuit of the voice coil motor in a single-polarity modulation mode in the step 1, the input power supply voltage of the driving circuit is positive voltage + U and negative voltage-U; switch tube T₁And a freewheeling diode D₁Form an upper bridge arm and a switch tube T₂And a freewheeling diode D₂The pulse width modulation driving signals of the bridge arms are PWM1 and PWM2 respectively, the PWM1 controls the on and off of the upper bridge arm, the PWM2 controls the on and off of the lower bridge arm, and the switch tube T is switched on when the lower bridge arm works in the forward direction₁Freewheel diode D₂And a load to form a voltage reduction circuit, and T is in reverse operation₂Freewheel diode D₂And the load form a voltage reduction circuit; and a voice coil motor equivalent model represented by the series connection of the resistor R and the inductor L, namely a load, is connected between the midpoint of the two bridge arms and the ground.

Step 1 is specifically carried out as follows:

when the circuit enters steady state and T₁T is more than or equal to 0 and less than or equal to DT when the current is set as i₁From kirchhoff's voltage law:

wherein, U is voltage, R is equivalent resistance of the voice coil motor coil, and L is equivalent inductance of the voice coil motor coil;

let the initial value of current at this stage be I₁₀Definition ofSolving the above differential equation yields:

in the formula, e is the base number of the natural logarithm, and t is a time variable;

when T is₁At turn-off, D₂On, let the current be i₂From kirchhoff's voltage law:

the initial value of the current obtained at this stage is I₂₀Solving the above equation can yield:

in the formula, t_onIs a switch tube T₁The on-time (t) is the time when the PWM wave is at high level, t is a time variable and t is more than or equal to t_on；

Since the circuit is in steady state, it can be seen from fig. 2 that:

I₁₀＝i₂(T)＝I_min，I₂₀＝i₁(DT)＝I_max (5)

in the formula i₂(T) is a current i₂Value at time T, i₁(DT) is a current i₁Value at time DT, I_minIs the minimum value of the load current, I_maxIs the maximum value of the load current;

then, from the above equation:

in the formula, t₁DT is a switch tube T₁The end point of conduction of (1);

the average of the output current over a period can be approximated as:

in the formula, D is a duty ratio, T is a period of the PWM wave, and formula (8) is an average value of the output current of the voice coil motor.

Step 2, outputting average current by using the voice coil motor under the unipolar modulation mode obtained in the step 1, and superposing sinusoidal flutter pulse width on a duty ratio generation algorithm;

when the voice coil motor is driven to reach a designated position, if the driving current is kept unchanged, the output displacement of the voice coil motor is also unchanged (in a static state), and when the current is changed, the movable coil part of the voice coil motor can move by overcoming resistance force including static friction force, so that the response speed is reduced due to obvious hysteresis. According to the invention, a small-amplitude low-frequency sinusoidal signal with zero mean value is superposed on the output current, so that the movable coil part of the voice coil motor is always in a micro-sliding state, the static friction force is converted into the dynamic friction force, the response speed and the sensitivity are improved, and the lag is reduced. The superimposed small low-frequency sinusoidal signal with zero mean is referred to as a dither signal in the present invention.

From the formula (8), I_d0If the duty ratio D is subjected to low-frequency small-amplitude sinusoidal disturbance, the current I is output according to the D_dAnd will necessarily exhibit sinusoidal fluctuations of the same frequency.

Step 2 is specifically carried out as follows:

defining the flutter signal modulation ratio:

obviously rho epsilon [0,1], the dither additional current in sinusoidal form is:

wherein the parameter omega is 2 pi/T₂Period T of₂＝(20～100)T₁The positive integer k belongs to N; i is_d0The current is the current when no flutter is added;

the final current is:

in the formula I_diA dither additional current of sinusoidal form shown in formula (10);

the taylor series approximation for equation (6) can be obtained:

from equation (8):

the formula shows that:

in the formula, D_kThe duty ratio corresponding to the load current after superimposing the dither current shown in equation (11).

Substituting equation (11) can result in

D_k＝D+pDsin(ωT₁k)/2 (15)

Where rho is [0,1]]For the dither signal modulation ratio, D is the original duty cycle, D_kThe duty ratio is corresponding to the current containing the flutter.

The above formula shows D_kThe device consists of two parts of a duty ratio when no flutter is added and a variable quantity added by flutter with a period of omega. Can be seen in the output messagePositive half cycle of number, duty cycle D_kFrom D_kBeginning to increase to the maximum D according to the sine rule_kD + ρ D/2, and then gradually decreased to D_kD; in the negative half cycle of the output signal, duty ratio D_kFrom D_kBeginning with a sinusoidal law, gradually decreasing to a minimum D_kD- ρ D/2, then gradually increased again to D_k＝D。

And 3, controlling the voice coil motor by using the pulse width modulation duty ratio generation algorithm superposed with the sine-form flutter and designed in the step 2 to finish flutter regulation.

Step 3 specifically is to generate a corresponding pulse width modulation waveform, i.e., PWM1 or PWM2, by using a duty ratio generation algorithm shown in formula (15), so as to control the switching on and off of the switching tube T1 or T2, thereby completing the control of the voice coil motor. Under the control of the duty ratio, the average current output by the voice coil motor shows the sinusoidal characteristic with the same frequency as the flutter signal, so that the movable coil part of the voice coil motor is always in a micro-sliding state, the response speed and the sensitivity of the voice coil motor are improved, and the hysteresis is reduced.

The invention relates to a flutter method for reducing hysteresis error of a switching mode driving voice coil motor, which comprises the following steps of: a method of superimposing sinusoidal-form dither signals in a duty cycle generation algorithm is presented.

Essentially, a small-amplitude low-frequency sinusoidal current signal with zero mean value is superposed on the output average current, so that the movable coil part of the voice coil motor is always in a micro-sliding state, static friction force is converted into dynamic friction, the response speed and sensitivity are improved, and hysteresis is reduced.

Meanwhile, the main body part of the duty ratio is generated according to the original mode of driving the voice coil motor in a switching mode, so that a hardware driving circuit is not required to be changed, and meanwhile, the parameters of the controller are determined according to the original parameter setting mode.

The voice coil motor is mainly used for generating linear displacement, and when the voice coil motor moves at high frequency, high speed and high acceleration, the non-monotonic complex hysteresis characteristic shown by the voice coil motor is very obvious, namely, a non-linear relation exists between input voltage and output displacement, so that a positioning error is caused, and the positioning precision of the voice coil motor is seriously influenced.

In order to meet the requirement that high positioning accuracy is required for equipment such as a photoetching machine and a quick reflection mirror, the reason why the output of a voice coil motor is delayed needs to be analyzed and possible processing methods need to be researched. Factors related to the hysteresis of the voice coil motor are many, including magnetic field, friction force, and gravitational field. In order to eliminate or compensate the hysteresis characteristic of the voice coil motor, the processing and assembling process level can be improved as much as possible when the voice coil motor is manufactured, but the hysteresis is improved by adopting a control method. The currently adopted methods include model-based feedforward control, high-gain feedback control and charge amplifier. Among them, the model-based feedforward control is very complicated in modeling, although it can effectively eliminate the hysteresis characteristic. The high-gain feedback control reduces the hysteresis characteristic by means of the trap, but the characteristic is severely degraded when the model parameter changes or the external environment changes. Implementation with a charge amplifier is inherently easy, but bias voltage mitigation provided in the circuit severely impacts control performance.

When the output of the voice coil motor driven by the switching mode reaches a specified position, the driving current is kept unchanged, as shown in fig. 3, the output displacement of the voice coil motor is also unchanged, the duty ratio of the PWM signal is unchanged, and as shown in fig. 4, the movable part and the static part of the voice coil motor are kept static, and static friction force exists. However, when the displacement changes, the voice coil motor needs to overcome the static friction force, and starts moving from the static state, and has obvious lag so that the response speed is reduced. According to the waveform of the duty ratio at rest shown in fig. 4, if the duty ratio is allowed to change according to a sinusoidal law, as shown in fig. 5, the output average current shows a sinusoidal law change, i.e. a small current with zero average value and a small amplitude in the form of a low-frequency sine is superimposed on the output current of the voice coil motor, as shown in fig. 6, and the small current is a so-called "flutter" signal. Under the current drive of superposed flutter signal, the movable coil part of voice coil motor can be in the slip state of small amplitude all the time to convert static friction into kinetic friction, and then can reduce the hysteresis, improve response speed and sensitivity, be favorable to realizing displacement and angle control of high accuracy.

Comparing the measured output characteristic curves, the following conclusions can be drawn:

1) as can be seen from fig. 7, after the dither is added, the hysteresis characteristic surrounding area of the output characteristic curve is obviously reduced (close to half), the original maximum hysteresis difference H1 is 0.093mm, the maximum hysteresis difference H2 after the dither is added is 0.051mm, the original hysteresis error is 11.62%, and the hysteresis error after the dither is added is 6.37%.

2) As can be seen from the comparison of FIG. 8 and FIG. 9, the coefficient of determination of the regression analysis changed from 0.9687 to 0.987 after the addition of the chatter, and the linearity was improved;

the flutter signal in a superposed sine form is output by the pulse width of the voice coil motor in a switching mode, so that the hysteresis of the output characteristic curve of the voice coil motor is compensated, the hysteresis surrounding area is reduced by nearly half, and the compensation effect is very obvious.

Examples

In the flutter method for reducing the hysteresis error of the voice coil motor driven by the switching mode, the coil equivalent resistance of the voice coil motor is 5.1 omega, the coil equivalent inductance is 0.9mH, the power is 40W, the frequency of a unipolar modulation reversible PWM circuit is 4kHz, a switching tube is a power MOSFET, a diode is a fast recovery diode, the flutter frequency is 50Hz, the power supply voltage is 24V, and the modulation ratio p is 0.2. The displacement is measured by an eddy current micro-displacement sensor, the displacement is +/-0.5 mm, and the output voltage is +/-10V. The experimental setup is shown in fig. 10. And (3) constructing a voice coil motor pulse width modulation driver and measuring an output characteristic curve of the voice coil motor by using the pulse width modulation duty ratio generation algorithm superposed with the sine-form flutter and designed in the step (2), and comparing the output characteristic curve with the output characteristic curve without using the flutter algorithm, as shown in fig. 7.

The invention discloses a flutter method for reducing hysteresis errors of a switching mode driving voice coil motor, which solves the problems that in the prior art, mathematical modeling is needed for eliminating and compensating the hysteresis characteristics of the voice coil motor, the process is complicated, and the control performance is reduced due to an external bias voltage circuit needed by a charge amplifier method, improves the response speed and improves the linearity. A small amplitude low-frequency flutter signal is superposed on a pulse width modulation output signal for driving a voice coil motor, even if the pulse width of output voltage changes in a sine rule, the average current flowing through a coil changes in a sine rule, so that static friction force is converted into sliding friction force, the response time from static to starting is shortened, the hysteresis characteristic can be obviously reduced, and the linearity is improved to a certain extent. The implementation is simple, a mathematical model of the voice coil motor hysteresis characteristic does not need to be established, and adverse effects caused by modeling errors are avoided; and a hardware circuit for driving the voice coil motor in a switching mode and a controller parameter setting mode are not required to be changed, so that the implementation cost is reduced.