Anti-recession anti-shake automatic correction method and control circuit thereof

Abstract

The invention discloses an anti-recession anti-shake automatic correction method and a control circuit thereof, and the method comprises the steps: responding to a received correction instruction, and controlling and changing an output voltage and an output current; testing time steps are sequentially carried out, the output voltage or the output current of the current testing time step is obtained and calculated according to the output voltage or the output current of the current testing time step when each testing time step is carried out, and then the counter electromotive force of the current testing time step is calculated and recorded; wherein the number of the test time steps is several; the method comprises the following steps: calculating and recording back electromotive forces of all test time steps, calculating change parameters according to the recorded back electromotive forces, and adjusting and storing anti-shake control gains or / and delay compensation according to the change parameters, thereby realizing anti-shake automatic correction. According to the invention, the technical problem that closed-loop control compensation cannot be realized because the driving motor is used in a long-time driving period or falls off in anti-shake control in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of anti-shake control, and in particular to an anti-fading anti-shake automatic correction method and a control circuit thereof. Background Art

[0002] With the development of small portable electronic devices with shooting and video functions, such as smart phones, sports cameras, law enforcement recorders, smart glasses and driving recorders, when taking photos or videos through the above devices, the photos or videos taken may be blurred and shaken due to external vibrations, which in turn affects the quality of the photos or videos. This problem will be more serious when the vibration is more intense or in low light environments.

[0003] At present, there are many different anti-shake technologies. One of the anti-shake control methods adopts a sensor-type closed-loop anti-shake control algorithm and circuit, which requires adding a position sensor and additional pins to the motor, resulting in more complex anti-shake motors and module drive circuits and chips, and increasing the size and cost of the motors and modules. There is also an anti-shake control through open-loop control, but because of the use of open-loop control, it is easy for the anti-shake motor to resonate or move unwanted movements due to external vibrations, increasing the risk of image blur caused by the resonance or movement. In addition, if the motor mechanically degrades after long-term use or after falling, the above-mentioned open-loop control algorithm and circuit cannot compensate for the degradation through closed-loop control. When the degradation occurs, the open-loop anti-shake performance may be significantly deteriorated.

[0004] Therefore, there is an urgent need for a method that can prevent the motor from mechanically degrading after long-term use or falling, resulting in the inability to achieve closed-loop control compensation. Summary of the invention

[0005] The present invention provides an anti-fading and anti-shaking automatic correction method and a control circuit thereof, so as to solve the technical problem in the prior art that the closed-loop control compensation cannot be realized due to mechanical degradation of the driving motor after long-term use or falling.

[0006] In order to solve the above technical problems, an embodiment of the present invention provides an anti-fading and anti-shake automatic correction method, comprising:

[0007] In response to receiving the correction instruction, controlling and changing the output voltage and the output current;

[0008] Enter the test time step in sequence, and when entering each test time step, obtain and calculate the first coil resistance of the current test time step according to the output voltage or output current of the current test time step, and then calculate and record the back electromotive force of the current test time step; wherein the number of the test time steps is several;

[0009] Until the back electromotive force of all test time steps is calculated and recorded, the change parameter is calculated according to the recorded back electromotive force, and the anti-shake control gain and / or delay compensation are adjusted and stored according to the change parameter, so as to realize automatic anti-shake correction.

[0010] As a preferred solution, the controlling and changing of the output voltage and the output current specifically includes:

[0011] When performing anti-shake control, the output voltage and output current of the driving circuit are controlled and changed according to the acquired preset closed-loop anti-shake control data.

[0012] As a preferred solution, the method for obtaining the preset closed-loop anti-shake control data specifically includes:

[0013] Enter the control time step in sequence, so that in each control time step, the second coil resistance of the current control time step is read and calculated according to the driving current and driving voltage of the current control time step, and the back electromotive force of the current control time step is calculated according to the driving current, driving voltage and second coil resistance of the current control time step, and the preset anti-shake compensation angle of the next moment is obtained, and the preset closed-loop anti-shake control data of the next moment is calculated according to the back electromotive force, driving current, driving voltage and second coil resistance of the current control time step and the preset anti-shake compensation angle of the next moment; wherein the number of the control time steps is several.

[0014] As a preferred solution, the first coil resistance of the current test time step is obtained and calculated according to the output voltage or output current of the current test time step, and then the back electromotive force of the current test time step is calculated and recorded, specifically:

[0015] After controlling and changing the output voltage and the output current, the output voltage and the output current of the current test time step are obtained;

[0016] Calculating the resistance of the first coil at the current test time step according to the output voltage and output current at the current test time step;

[0017] The back electromotive force of the current test time step is calculated according to the output voltage, the output current and the first coil resistance of the current test time step.

[0018] As a preferred solution, the method of calculating the change parameter according to the recorded back electromotive force, and adjusting and storing the anti-shake control gain and / or delay compensation according to the change parameter specifically includes:

[0019] According to the recorded back electromotive force, two different maximum values ​​of the back electromotive force and their corresponding times are randomly selected; wherein the two different back electromotive forces selected are respectively the first maximum electromotive force and the second maximum electromotive force;

[0020] Calculating a variation parameter according to the first maximum electromotive force and the second maximum electromotive force; the variation parameter includes one or both of a resonance frequency and a damping coefficient;

[0021] The anti-shake control gain is adjusted according to the resonance frequency, and the anti-shake control gain and delay compensation are adjusted according to the resonance frequency and the damping coefficient, and the anti-shake control gain and delay compensation are stored.

[0022] As a preferred solution, the calculation formula of the resonance frequency is:

[0023]

[0024] Among them, f i is the resonant frequency of coil group i, s represents the first maximum electromotive force of the sth coil, q represents the second maximum electromotive force of the qth coil, t i,s represents the time step corresponding to the first maximum electromotive force, t i,q represents the time step corresponding to the second maximum electromotive force;

[0025] The calculation formula of the damping coefficient is:

[0026]

[0027] Among them, i is the damping coefficient of coil group i.

[0028] Accordingly, the present invention further provides a control circuit for automatic correction of anti-fading and anti-shake, which is used to execute the automatic correction method of anti-fading and anti-shake as described in any one of the above, comprising: at least one closed-loop anti-shake control module, at least one resistance calculation module, at least one back electromotive force calculation module, at least one memory and at least one application circuit; each of the closed-loop anti-shake control modules is connected to a corresponding resistance calculation module, a back electromotive force calculation module, a memory and an application circuit;

[0029] Each of the application circuits includes a driving circuit, a sensing circuit connected to the driving circuit, and a multi-axis anti-shake motor.

[0030] As a preferred solution, each of the resistance calculation modules reads the output voltage and output current of at least one multi-axis anti-shake motor in the application circuit, and calculates the resistance of the first coil according to the output voltage and output current;

[0031] Each of the back electromotive force calculation modules reads the at least one first coil resistance, at least one output voltage and at least one output current, calculates and outputs the back electromotive force of at least one multi-axis anti-shake motor;

[0032] The closed-loop anti-shake control module is used to control and change the output voltage and output current in response to receiving the correction instruction; record the back electromotive force of all test time steps, calculate the change parameter according to the recorded back electromotive force, and adjust the anti-shake control gain and delay compensation according to the change parameter;

[0033] The memory is used to store the anti-shake control gain and delay compensation.

[0034] As a preferred solution, it also includes: an anti-shake compensation angle calculation module;

[0035] The anti-shake compensation angle calculation module is used to read the signal of the vibration sensor and calculate the multi-axis anti-shake compensation angle and / or distance, so as to output the multi-axis anti-shake compensation angle and / or distance to the closed-loop anti-shake control module.

[0036] As a preferred solution, the application circuit specifically includes a current driving circuit, a first sensing circuit, a second sensing circuit, a microcontroller, a vibration sensor and a multi-axis anti-shake motor;

[0037] The microcontroller is connected to the vibration sensor, the second sensing circuit and the current driving circuit respectively;

[0038] The current driving circuit is connected to the multi-axis anti-shake motor through the first sensing circuit, and the first sensing circuit is connected to the second sensing circuit.

[0039] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0040] The technical solution of the present invention can respond to the correction instruction received without the need for special instruments or environment, and can be automatically performed in a static state, so that customers can perform it at any time, and greatly reduce the cost and time required for automatic correction, control and change the output voltage and output current, and then enter the test step in turn, so as to obtain the coil resistance in each test step, and finally obtain the back electromotive force of the current test step, and calculate the change parameter in combination with the obtained back electromotive force, and then adjust the storage anti-shake control gain and / or delay compensation. At the same time, the present invention does not need to add additional sensors to the motor, so the anti-shake motor and camera module can be simplified, and the size and cost of the motor and module can be reduced. Through closed-loop control, the anti-shake effect can be avoided due to mechanical decay. The present invention achieves excellent anti-shake effect and reduces the risk of image blur due to resonance. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 : A schematic diagram of the structure of a control circuit for automatic correction of anti-fading and anti-shake provided by an embodiment of the present invention;

[0042] Figure 2 : A schematic diagram of the structure of a control circuit for automatic correction of anti-fading and anti-shake provided by another embodiment of the present invention;

[0043] Figure 3 : A schematic diagram of the structure of an application circuit provided by an embodiment of the present invention;

[0044] Figure 4 : A schematic diagram of the structure of an application circuit provided by another embodiment of the present invention;

[0045] Figure 5 : A flowchart of the steps of an anti-fading and anti-shake automatic correction method provided by an embodiment of the present invention;

[0046] Figure 6 : A flow chart of the anti-shake control stage provided by an embodiment of the present invention;

[0047] Figure 7 : A flow chart of the anti-fading automatic correction provided by an embodiment of the present invention;

[0048] Figure 8 : A schematic diagram of the back electromotive force measured during automatic correction provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0049] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] Embodiment 1

[0051] See also Figure 1 , which is a control circuit for automatic correction of anti-fading and anti-shake provided by the present invention, including: at least one closed-loop anti-shake control module, at least one resistance calculation module, at least one back-electromotive force calculation module, at least one memory and at least one application circuit; each of the closed-loop anti-shake control modules is connected to a corresponding resistance calculation module, a back-electromotive force calculation module, a memory and an application circuit; each of the application circuits includes a driving circuit and an induction circuit and a multi-axis anti-shake motor connected to the driving circuit.

[0052] As a preferred solution of this embodiment, each of the resistance calculation modules reads the output voltage and output current of at least one multi-axis anti-shake motor in the application circuit, and calculates the first coil resistance based on the output voltage and output current; each of the back-electromotive force calculation modules reads the at least one first coil resistance, at least one output voltage and at least one output current, calculates and outputs the back-electromotive force of at least one multi-axis anti-shake motor; the closed-loop anti-shake control module is used to control and change the output voltage and output current in response to receiving a correction instruction; the back-electromotive force of all test time steps is recorded, and the change parameter is calculated based on the recorded back-electromotive force, and the anti-shake control gain and delay compensation are adjusted based on the change parameter; the memory is used to store the anti-shake control gain and delay compensation.

[0053] It should be noted that each resistance calculation module reads at least one voltage and at least one current that drive at least one multi-axis anti-shake motor, calculates and outputs at least one coil resistance in the multi-axis anti-shake motor; each back-electromotive force calculation module reads at least one resistance, at least one voltage and at least one current, calculates and outputs at least one coil back-electromotive force (Back Counter-Electromotive Force) in at least one multi-axis anti-shake motor; in the anti-shake working mode, each closed-loop anti-shake control module reads the correction parameters in the memory, and reads the anti-shake compensation angle and / or distance, as well as the at least one coil resistance and at least one back-electromotive force, calculates and outputs at least one closed-loop anti-shake control, drives the at least one multi-axis anti-shake motor to perform anti-shake movement, compensates for image blur caused by vibration, and improves image clarity.

[0054] Preferably, the at least one multi-axis anti-shake motor is a voice coil motor or a servo motor, which is composed of multiple sets of coils and magnets.

[0055] Preferably, the anti-shake control output by the at least one closed-loop anti-shake control module is a voltage (u k =V k ), that is, using voltage to drive at least one multi-axis anti-shake motor to perform anti-shake movement.

[0056] Preferably, the anti-shake control output by the at least one closed-loop anti-shake control module is a current (u k =I k ), that is, using electric current to drive at least one multi-axis anti-shake motor to perform anti-shake movement.

[0057] It should be noted that the speed at which the multiple coils of the multi-axis anti-shake motor move relative to the magnet It will affect the back electromotive force (E k ), and voltage (V k ) and current (Ik ). When the moving speed increases, the absolute value of the back electromotive force will also increase.

[0058] Implementing the embodiments of the present invention has the following effects:

[0059] The present invention requires at least one microcontroller, at least one driving circuit, at least one amplifier, and at least one analog-to-digital converter, which are common in traditional anti-shake control chips. Therefore, the present invention does not need to add additional sensors to the motor, so the anti-shake motor and camera module can be simplified, and the size and cost of the motor and module can be reduced. Therefore, when applying the algorithm and circuit of the present invention, a traditional anti-shake control chip can be used to simplify external electronic components and circuits, and reduce cost and volume.

[0060] Embodiment 2

[0061] See also Figure 2 The embodiment of the present invention is based on a control circuit for automatic correction of anti-fading and anti-shake in embodiment one, and further includes: an anti-shake compensation angle calculation module; the anti-shake compensation angle calculation module is used to read the signal of the vibration sensor and calculate the multi-axis anti-shake compensation angle and / or distance, thereby outputting the multi-axis anti-shake compensation angle and / or distance to the closed-loop anti-shake control module.

[0062] In this embodiment, by adding an anti-shake compensation angle calculation module, the signal of the vibration sensor is read, the multi-axis anti-shake compensation angle and / or distance is calculated, and output to the closed-loop anti-shake control module. In addition, the control circuit in the second embodiment includes a memory, which can store the control signal (current or voltage) of the closed-loop anti-shake control module for use by the resistance calculation module and the back electromotive force calculation module at the next time step, and there is no need to read the relevant signal through the sensing circuit, so as to achieve a simpler sensing circuit.

[0063] Embodiment 3

[0064] See also Figure 3, which is the application circuit in the first or second embodiment of the present invention, comprising a current driving circuit, two sensing circuits, a microcontroller, a vibration sensor, and a multi-axis anti-shake motor; the sensing circuit 1 comprises a plurality of resistors and capacitors, forming a plurality of low-pass filters, connected to the output of the current driving circuit, filtering the high-frequency noise in the output; the current driving circuit, the first sensing circuit and a microcontroller are integrated in an anti-shake control chip; the second sensing circuit comprises a plurality of amplifiers and a multi-channel analog-to-digital converter (Multi-Channel Analog-to-Digital Converter); the input of the second sensing circuit is connected to the filtered output of the first sensing circuit; the output of the second sensing circuit is connected to the input of the microcontroller; through the first sensing circuit and the second sensing circuit, the microcontroller can read multiple output voltages of the current driving circuit; through the memory, the current of the multi-axis anti-shake motor of the microcontroller in the previous time step; after the microcontroller reads the vibration sensor and performs the anti-shake compensation angle calculation algorithm and the anti-fading sensorless closed-loop anti-shake control algorithm, it calculates and outputs a control signal to the current driving circuit, and stores the current in the memory of the microcontroller for use by the above two algorithms in the next time step.

[0065] As a preferred solution of this embodiment, the application circuit specifically includes a current driving circuit, a first sensing circuit, a second sensing circuit, a microcontroller, a vibration sensor and a multi-axis anti-shake motor; the microcontroller is respectively connected to the vibration sensor, the second sensing circuit and the current driving circuit; the current driving circuit is connected to the multi-axis anti-shake motor through the first sensing circuit, and the first sensing circuit is connected to the second sensing circuit.

[0066] Embodiment 4

[0067] See also Figure 4 , which is an embodiment of the present invention based on the application circuit in embodiment one or embodiment two. The embodiment of the present invention is similar to embodiment three, but this embodiment adopts a voltage driving circuit, a different combination of capacitors and resistors of the first sensing circuit, a microcontroller reading multiple currents of the voltage driving circuit through the first sensing circuit and the second sensing circuit, and the microcontroller calculating and outputting the driving voltage, and storing the relevant signals in the memory of the microcontroller.

[0068] As a preferred solution of this embodiment, the application circuit specifically includes a current driving circuit, a first sensing circuit, a second sensing circuit, a microcontroller, a vibration sensor and a multi-axis anti-shake motor; the microcontroller is respectively connected to the vibration sensor, the second sensing circuit and the current driving circuit; the current driving circuit is connected to the multi-axis anti-shake motor through the first sensing circuit, and the first sensing circuit is connected to the second sensing circuit.

[0069] Because the anti-shake control chips in the third and fourth embodiments are close to the popular control chips on the market, when the algorithms and circuits in the third and fourth embodiments are applied, conventional anti-shake control chips can be used to simplify external electronic components and circuits, thereby reducing costs and volume.

[0070] Embodiment 2

[0071] Please refer to Figure 5 , an anti-fading and anti-shake automatic correction method provided by an embodiment of the present invention is implemented by the anti-fading and anti-shake automatic correction control circuit of any one of the embodiments 1 to 4, including the following steps S101-S103:

[0072] Step S101: in response to receiving a correction instruction, controlling and changing the output voltage and the output current.

[0073] As a preferred solution of this embodiment, the controlling and changing of the output voltage and the output current specifically includes:

[0074] When performing anti-shake control, the output voltage and output current of the driving circuit are controlled and changed according to the acquired preset closed-loop anti-shake control data.

[0075] As a preferred solution of this embodiment, the method for obtaining the preset closed-loop anti-shake control data specifically includes:

[0076] Enter the control time step in sequence, so that in each control time step, the second coil resistance of the current control time step is read and calculated according to the driving current and driving voltage of the current control time step, and the back electromotive force of the current control time step is calculated according to the driving current, driving voltage and second coil resistance of the current control time step, and the preset anti-shake compensation angle of the next moment is obtained, and the preset closed-loop anti-shake control data of the next moment is calculated according to the back electromotive force, driving current, driving voltage and second coil resistance of the current control time step and the preset anti-shake compensation angle of the next moment; wherein the number of the control time steps is several.

[0077] In this example, see Figure 6 The steps of the anti-shake control stage are as follows: a resistance calculation module reads all the voltages (V k-1 ) and current (Ik-1 ), calculate and output all the second coil resistances (R k-1 ); the back electromotive force calculation module reads all the resistances, voltages and currents, calculates and outputs the back electromotive force (E) of all the coils in a multi-axis anti-shake motor k-1 ); the closed-loop anti-shake control module reads the anti-shake compensation angle and / or distance (θ k ), and the resistance and back electromotive force of each coil, and calculate and output closed-loop anti-shake control (u k ), then wait for a time step (k=k+1), and repeat the above steps.

[0078] In this embodiment, when n is the number of coil groups in all the multi-axis anti-shake motors (usually equal to the anti-shake compensation axes in the multi-axis anti-shake motor, which may include 3-axis tilt directions and 2-axis translation directions, but does not include translation directions along the optical axis), V i,k is the voltage of coil group i at time step k, I i,k is the current of coil group i at time step k, and R i,k is the resistance of coil group i at time step k. The main equations in all resistance calculation modules are as follows:

[0079] V k =[V 1,k ,…,V i,k ,…,V n,k ] (Equation 1)

[0080] I k =[I 1,k ,…,I i,k ,…,I n,k ] (Equation 2)

[0081] R k =[R 1,k ,…,R i,k ,…,R n,k ] (Equation 3)

[0082]

[0083] When E i,k is the back EMF of coil group i at time step k. The main equations in all back EMF modules are as follows:

[0084] E k =[E 1,k ,…,E i,k ,…,E n,k ] (Equation 5)

[0085] E i,k-1 =Vi,k-1 -I i,k-1 R i,k-1 (Equation 6)

[0086] When θ i,k is the anti-shake compensation angle and / or distance of the j-th axis at time step k, is the anti-shake compensation speed of the i-th axis at time step k, u i,k is the closed-loop control output to the drive circuit and coil group i at time step k, and a i is the gain of the corresponding coil group i in the closed-loop anti-shake control. The main equations in all closed-loop anti-shake control modules are as follows:

[0087] u k =[u 1,k ,…,u i,k ,…,u n,k ] (Equation 7)

[0088] θ k =[θ 1,k ,…,θ i,k ,…,θ n,k ] (Equation 8)

[0089]

[0090] G in Equation 10 i (θ k ) is θ k The function is to compensate the angle θ according to the input k Calculate the open-loop control output to the drive circuit and coil group i. yes The function is to compensate the speed according to the input Calculate the delay compensation control output to the drive circuit and coil group i. a in equation 10 i E i,k-1 It is to add closed-loop control elements on the basis of open-loop delay compensation control and delay compensation control to achieve the effect of closed-loop control, change the characteristics of the anti-shake motor, improve the anti-shake performance and reduce the risk of image blur due to resonance.

[0091] In the calibration mode, each closed-loop anti-shake control module measures and records m groups of back electromotive force [E1,…,E k ,…,E m ] data, and calculate the back electromotive force to calculate the new first-order resonance frequency (f) of the multi-axis anti-shake motor. According to the resonance frequency (f), the new control parameters can be calculated to adjust G i The gain parameter in .

[0092] Preferably, each closed-loop anti-shake control module measures the resonance frequency (f) and the damping coefficient (ζ) at the same time; according to the resonance frequency (f) and the damping coefficient (ζ), a new control parameter can be calculated to adjust H i The gain parameter in .

[0093] Preferably, the at least one multi-axis anti-shake motor is a voice coil motor or a servo motor, which is composed of multiple sets of coils and magnets.

[0094] Preferably, the anti-shake control output by the at least one closed-loop anti-shake control module is a voltage (u k =V k ), that is, using voltage to drive at least one multi-axis anti-shake motor to perform anti-shake movement.

[0095] Preferably, the anti-shake control output by the at least one closed-loop anti-shake control module is a current (u k =I k ), that is, using electric current to drive at least one multi-axis anti-shake motor to perform anti-shake movement.

[0096] Preferably, the sensorless closed-loop anti-shake control algorithm for resisting decay stores the output voltage (V k ) or current (I k ) in at least one memory for use by the algorithm calculation at the next time step.

[0097] Preferably, each of the multi-axis anti-shake motors comprises at least one spring oscillator system; by adjusting the gain (a i ), to achieve the damping ratio (ζ i ) is between 0.4 and 1.4 (close to the critical damping state).

[0098] Specifically, the application circuit for executing the above anti-shake control stage is as follows: Figure 1 As shown, it specifically includes: a memory, a driving circuit, a sensing circuit, and a multi-axis anti-shake motor; the closed-loop anti-shake control module first reads the correction parameters from the memory, including G in equation 10 i , H i and a i ; The one driving circuit outputs anti-shake control according to the algorithm to drive the one multi-axis anti-shake motor; the one sensing circuit detects all voltages and currents output by the one driving circuit to the one multi-axis anti-shake motor, and outputs them to the algorithm (including a resistance calculation module, a back electromotive force calculation module, and a closed-loop anti-shake control module); the algorithm calculates and outputs closed-loop anti-shake control according to the input anti-shake compensation angle and the voltage and current.

[0099] Among them, the moving speed of multiple coils of the multi-axis anti-shake motor relative to the magnet It will affect the back electromotive force (E k ), and voltage (V k ) and current (I k ). When the moving speed increases, the absolute value of the back electromotive force will also increase. The above-mentioned anti-shake control stage algorithm and application circuit can drive the multi-axis anti-shake motor to perform anti-shake movement, compensate for image blur caused by vibration, and improve image clarity.

[0100] It should be noted that when the closed-loop anti-shake control module receives the instruction to enter the correction, it will perform automatic correction steps. After completion, the correction parameters will be stored in the memory for future closed-loop anti-shake use.

[0101] Step S02: Enter the test time steps in sequence, and when entering each test time step, obtain and calculate the first coil resistance of the current test time step based on the output voltage or output current of the current test time step, and then calculate and record the back electromotive force of the current test time step; wherein, there are several test time steps.

[0102] As a preferred solution of this embodiment, the first coil resistance of the current test time step is obtained and calculated according to the output voltage or output current of the current test time step, and then the back electromotive force of the current test time step is calculated and recorded, specifically:

[0103] After controlling and changing the output voltage and the output current, the output voltage and the output current of the current test time step are obtained; the first coil resistance of the current test time step is calculated according to the output voltage and the output current of the current test time step; the back electromotive force of the current test time step is calculated according to the output voltage, the output current and the first coil resistance of the current test time step.

[0104] In this embodiment, preferably, the back electromotive force can be calculated by Equation 6.

[0105] Step S103: until the back electromotive force of all test time steps is calculated and recorded, the change parameter is calculated according to the recorded back electromotive force, and the anti-shake control gain and / or delay compensation is adjusted and stored according to the change parameter, so as to realize automatic anti-shake correction.

[0106] As a preferred solution of this embodiment, the calculation of the change parameter based on the recorded back electromotive force, and the adjustment and storage of the anti-shake control gain and / or delay compensation based on the change parameter specifically include:

[0107] According to the recorded back electromotive force, two different maximum values ​​of the back electromotive force and their corresponding times are randomly selected; wherein the two different back electromotive forces selected are the first maximum electromotive force and the second maximum electromotive force respectively; according to the first maximum electromotive force and the second maximum electromotive force, the change parameter is calculated; the change parameter includes one or two of the resonant frequency and the damping coefficient; according to the resonant frequency, the anti-shake control gain is adjusted, and according to the resonant frequency and the damping coefficient, the anti-shake control gain and the delay compensation are adjusted, and the anti-shake control gain and the delay compensation are stored.

[0108] As a preferred solution of this embodiment, the calculation formula of the resonance frequency is:

[0109]

[0110] Among them, f i is the resonant frequency of coil group i, s represents the first maximum electromotive force of the sth coil, q represents the second maximum electromotive force of the qth coil, t i,s represents the time step corresponding to the first maximum electromotive force, t i,q Indicates the time step corresponding to the second maximum electromotive force.

[0111] The calculation formula of the damping coefficient is:

[0112]

[0113] Among them, i is the damping coefficient of coil group i.

[0114] In this example, see Figure 7 , which is the steps of the anti-fading sensorless closed-loop anti-shake control algorithm of the embodiment of the present invention when performing anti-fading automatic correction, including: S1, when the time step k=1, the closed-loop anti-shake control module changes the output voltage or current (u0, that is, I0 or V0); S2, wait for a time step (k=k+1); S3, according to I k-1 、V k-1 and R k-1 The back electromotive force calculation module calculates the back electromotive force (E k-1 ), and record; S4, repeat steps S2 to S3 until k>m; S5, calculate the change of resonance frequency and / or damping coefficient according to the recorded back electromotive force, and adjust the anti-shake control gain and delay compensation according to the change, and store the new correction parameters in the memory; wherein, the value of m can be set according to actual needs.

[0115] In this example, see Figure 8 , the back electromotive force (E i,k). In this example, when the closed-loop anti-shake control module changes the output voltage or current, relative movement occurs between the coil and the magnet, causing the back EMF to rise rapidly. Then, due to the spring oscillator system in the anti-shake motor, it changes in a sinusoidal manner. i,q and b i,s ) and time (t i,q and t i,s ), the first-order resonant frequency (f i ) and damping coefficient (ζ i ), the equation is as follows:

[0116]

[0117] f=[f1,…,f i ,…,f n ] (Equation 12)

[0118]

[0119] ζ=[ζ1,…,ζ i ,…,ζ n ] (Equation 14)

[0120] Based on the resonant frequency (f), new control parameters can be calculated to adjust G i For example, the spring constant (K) of the spring oscillator system of the anti-shake motor after falling i ∝(f i ) 2 ) drops, resulting in a decrease in anti-shake performance. The closed-loop anti-shake control module finds a drop in the resonance frequency during the automatic correction process, and the closed-loop anti-shake control module adjusts G according to the change in the resonance frequency. i The gain parameter in the image stabilization function compensates for the drop in spring constant and reduces the drop in image stabilization performance.

[0121] In this embodiment, since the resonant frequency (f i ) is proportional to the spring constant, so G can be changed according to the change of the resonant frequency. i Among them, the control parameters include G i and H i The gain parameter.

[0122] Preferably, according to the resonant frequency (f) and the damping coefficient (ζ), a new control parameter can be calculated to adjust H iFor example, the damping coefficient and control system delay of the spring oscillator system of the anti-shake motor change after a fall, resulting in a decrease in anti-shake performance. The closed-loop anti-shake control module finds that the damping coefficient has changed during the automatic correction process, and the closed-loop anti-shake control module will adjust H according to the change in the damping coefficient. i The gain parameter in compensates for the impact caused by the change of damping coefficient and reduces the degradation of anti-shake performance.

[0123] It can be understood that the present invention is combined with the corresponding application circuit, by adjusting the a of equation 10 in the anti-fading sensorless closed-loop anti-shake control algorithm in the microprocessor i (the gain of the corresponding coil group i in the closed-loop anti-shake control) can change the damping coefficient of the spring oscillator system in the multi-axis anti-shake motor. i , can achieve a larger damping coefficient and damping ratio.

[0124] Preferably, when the damping ratio is adjusted to between 0.4 and 1.4 (near critical damping), the multi-axis anti-shake motor can achieve a near-excellent anti-shake effect, reducing the risk of image blur due to resonance.

[0125] Since the algorithm and its application circuit in the embodiment do not need to add additional sensors to the motor, the motor and module can be effectively simplified, and the size and cost of the motor and module can be reduced.

[0126] In other embodiments, the coil resistance (R k-1 ) when adding relevant resistors in the driving circuit and the sensing circuit; changing the number of multi-axis anti-shake motors or the number of input channels; not storing the control output signal to the memory; changing the number and combination of resistance calculation modules, back electromotive force calculation modules or closed-loop anti-shake control modules; changing the number and combination of sensing circuits or driving circuits; changing the number and combination of analog-to-digital converters, amplifiers, resistors or capacitors in the sensing circuit; removing all capacitors in the sensing circuit; and removing the vibration sensor are also within the protection scope of the present invention.

[0127] Implementing the above embodiments has the following effects:

[0128] The technical solution of the present invention can respond to the correction instruction received without the need for special instruments or environment, and can be automatically performed in a static state, so that customers can perform it at any time, and greatly reduce the cost and time required for automatic correction, control and change the output voltage and output current, and then enter the test step in turn, so as to obtain the coil resistance in each test step, and finally obtain the back electromotive force of the current test step, and calculate the change parameter in combination with the obtained back electromotive force, and then adjust and store the anti-shake control gain and / or delay compensation. At the same time, the present invention does not need to add additional sensors to the motor, so the anti-shake motor and camera module can be simplified, and the size and cost of the motor and module can be reduced. Through closed-loop control, the anti-shake effect can be avoided due to mechanical decay. The present invention achieves excellent anti-shake effect and reduces the risk of image blur due to resonance.

[0129] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. It is particularly pointed out that for those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. An anti-fading and anti-shake automatic correction method, characterized in that: include: In response to receiving the correction instruction, controlling and changing the output voltage and the output current; Enter the test time step in sequence, and when entering each test time step, obtain and calculate the first coil resistance of the current test time step according to the output voltage or output current of the current test time step, and then calculate and record the back electromotive force of the current test time step; wherein the number of the test time steps is several; Until the back electromotive force of all test time steps is calculated and recorded, the change parameter is calculated according to the recorded back electromotive force, and the anti-shake control gain and / or delay compensation are adjusted and stored according to the change parameter, so as to realize automatic anti-shake correction.

2. The method for automatically correcting the fading and stabilization of the image according to claim 1, characterized in that: The controlling and changing of the output voltage or the output current specifically includes: When performing anti-shake control, the output voltage and output current of the driving circuit are controlled and changed according to the acquired preset closed-loop anti-shake control data.

3. The anti-fading and anti-shake automatic correction method according to claim 2, characterized in that: The method for obtaining the preset closed-loop anti-shake control data specifically includes: Enter the control time step in sequence, so that in each control time step, the second coil resistance of the current control time step is read and calculated according to the driving current and driving voltage of the current control time step, and the back electromotive force of the current control time step is calculated according to the driving current, driving voltage and second coil resistance of the current control time step, and the preset anti-shake compensation angle of the next moment is obtained, and the preset closed-loop anti-shake control data of the next moment is calculated according to the back electromotive force, driving current, driving voltage and second coil resistance of the current control time step and the preset anti-shake compensation angle of the next moment; wherein the number of the control time steps is several.

4. The method for automatically correcting the fading and stabilization of the image according to claim 1, wherein: The obtaining and calculating the first coil resistance of the current test time step according to the output voltage or output current of the current test time step, and then calculating and recording the back electromotive force of the current test time step, are specifically: After controlling and changing the output voltage or output current, obtaining the output voltage and output current of the current test time step; Calculating the resistance of the first coil at the current test time step according to the output voltage and output current at the current test time step; The back electromotive force of the current test time step is calculated according to the output voltage, the output current and the first coil resistance of the current test time step.

5. The method for automatic correction of anti-fading and anti-shake according to any one of claims 1 to 4, characterized in that: The step of calculating a change parameter based on the recorded back electromotive force, and adjusting and storing an anti-shake control gain and / or a delay compensation based on the change parameter specifically includes: According to the recorded back electromotive force, two different maximum values ​​of the back electromotive force and their corresponding times are selected; wherein the two different back electromotive forces selected are respectively the first maximum electromotive force and the second maximum electromotive force; Calculating a variation parameter according to the first maximum electromotive force and the second maximum electromotive force; the variation parameter includes one or both of a resonance frequency and a damping coefficient; The anti-shake control gain is adjusted according to the resonance frequency, and the anti-shake control gain and / or delay compensation are adjusted according to the resonance frequency and the damping coefficient, and the anti-shake control gain and / or delay compensation are stored.

6. The method for automatically correcting the fading and stabilization of claim 5, wherein: The calculation formula of the resonant frequency is: Among them, f i is the resonant frequency of coil group i, s represents the first maximum electromotive force of the sth coil, q represents the second maximum electromotive force of the qth coil, t i,s represents the time step corresponding to the first maximum electromotive force, t i,q represents the time step corresponding to the second maximum electromotive force; The calculation formula of the damping coefficient is: Among them, i is the damping coefficient of coil group i.

7. A control circuit for automatic correction of anti-fading and anti-shake, characterized in that: Used to execute the anti-fading anti-shake automatic correction method according to any one of claims 1 to 6, comprising: at least one closed-loop anti-shake control module, at least one resistance calculation module, at least one back electromotive force calculation module, at least one memory and at least one application circuit; each of the closed-loop anti-shake control modules is connected to a corresponding resistance calculation module, a back electromotive force calculation module, a memory and an application circuit; Each of the application circuits includes a driving circuit, a sensing circuit connected to the driving circuit, and a multi-axis anti-shake motor.

8. The control circuit for automatic correction of anti-fading and anti-shake as claimed in claim 7, characterized in that: Each of the resistance calculation modules reads the output voltage and output current of at least one multi-axis anti-shake motor in the application circuit, and calculates the resistance of the first coil according to the output voltage and output current; Each of the back electromotive force calculation modules reads the at least one first coil resistance, at least one output voltage and at least one output current, calculates and outputs the back electromotive force of at least one multi-axis anti-shake motor; The closed-loop anti-shake control module is used to control and change the output voltage and output current in response to receiving the correction instruction; record the back electromotive force of all test time steps, calculate the change parameter according to the recorded back electromotive force, and adjust the anti-shake control gain and delay compensation according to the change parameter; The memory is used to store the anti-shake control gain and delay compensation.

9. The control circuit for automatic correction of anti-fading and anti-shake according to any one of claims 7 to 8, characterized in that: Also includes: Anti-shake compensation angle calculation module; The anti-shake compensation angle calculation module is used to read the signal of the vibration sensor and calculate the multi-axis anti-shake compensation angle and / or distance, so as to output the multi-axis anti-shake compensation angle and / or distance to the closed-loop anti-shake control module.

10. The control circuit for automatic correction of anti-fading and anti-shake according to any one of claims 7 to 8, characterized in that: The application circuit specifically includes a current driving circuit, a first sensing circuit, a second sensing circuit, a microcontroller, a vibration sensor and a multi-axis anti-shake motor; The microcontroller is connected to the vibration sensor, the second sensing circuit and the current driving circuit respectively; The current driving circuit is connected to the multi-axis anti-shake motor through the first sensing circuit, and the first sensing circuit is connected to the second sensing circuit.

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