Solenoid valve flutter control method based on L9305 chip and correction method thereof

Abstract

The invention relates to the technical field of electromagnetic valve control, in particular to an electromagnetic valve flutter control method based on an L9305 chip and a correction method thereof, and the valve flutter control method comprises the following steps: obtaining Freq and Ftheo; s3, judging whether Ftheo meets the interval range requirement of Freq or not, if yes, executing S3, and if not, executing S4; the Nstep meeting the requirement and the Tstep corresponding to the Nstep are temporarily stored; judging whether indexing is completed or not, if yes, executing to obtain Tstep, and if not, judging and indexing; istep is obtained through calculation; and S7, synchronizing the spi instruction, and inputting the Nstep, the Tstep and the Istep into an L9305 chip so as to realize flutter control of the electromagnetic valve. According to the flutter control method, flutter control of the electromagnetic valve is achieved in the mode that the maximum current stepping change number Nstep is obtained through table look-up and indexing, then each stepping time duration Tstep corresponding to the maximum current stepping change number Nstep is obtained, and finally each stepping current variable quantity Istep is obtained, and the flutter control precision of the electromagnetic valve can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of solenoid valve control, and in particular to a solenoid valve flutter control method based on an L9305 chip and a correction method thereof. Background Art

[0002] Solenoid valve refers to: industrial equipment used for electromagnetic control, and is also an automated basic component used to control fluids. It belongs to an actuator and is not limited to hydraulics and pneumatics. It is mainly used in industrial control systems to adjust the direction, flow, speed and other parameters of the medium. The solenoid valve consists of two parts: an electromagnetic coil and a valve body. Its main principle is to use the electromagnetic force generated by the electromagnetic coil to push the valve core to achieve the on-off or steering of the fluid. In the field of solenoid valve control, especially the linear solenoid valves in automatic transmissions, electronic stability control and active suspension systems, its flutter function plays an important role in reducing the initial motion resistance, improving dynamic response, improving system stability, and avoiding viscous friction between the valve core and the valve sleeve; in the electro-hydraulic proportional control system, the real-time adjustment of the flutter signal is crucial to ensure the stability and reliability of the oil pressure control; the inductive reactance and impedance of the solenoid valve are important factors affecting the flutter control, which will affect the change of the current in the coil, thereby affecting the precise control of the flutter signal. To this end, we need to provide a solenoid valve flutter control method based on the L9305 chip and its correction method.

[0003] At present, the flutter control of solenoid valves relies on hardware improvements and PID control strategies, which have certain effects in reducing flutter. However, there are limitations in accurately controlling flutter (i.e., the lack of accurate flutter detection and analysis methods, resulting in inaccurate flutter control) and correcting flutter (i.e., the flutter correction strategy is not flexible enough and difficult to adapt to different working conditions and system changes). Especially under complex working conditions, the influence of the inductive reactance and impedance of the solenoid valve on flutter control has not been fully considered and effectively controlled, making it difficult to ensure the accuracy of flutter control. In addition, the system response and dynamic characteristics also affect the accuracy of flutter amplitude control. Electromagnetic interference and signal noise will also affect the transmission and execution of the flutter signal, resulting in inaccurate flutter amplitude control. The stability of the power supply and drive circuit will also lead to inaccurate flutter signal amplitude control, resulting in certain limitations in hardware improvements and PID control strategies in practical applications. Summary of the invention

[0004] In view of the shortcomings of the above-mentioned existing production technology, the applicant provides a solenoid valve flutter control method and correction method based on the L9305 chip with a reasonable structure. By improving the solenoid valve flutter control and correction method, the control and correction accuracy of the solenoid valve flutter can be improved.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A solenoid valve flutter control method based on L9305 chip, comprising the following steps:

[0007] S1, obtaining a requested dither frequency value F_req and a theoretical calculated dither frequency value F_theo of a required dither control solenoid valve;

[0008] S2, obtaining the requested flutter frequency value F_req and the theoretically calculated flutter frequency value F_theo in S1, and judging whether the theoretically calculated flutter frequency value F_theo meets the interval range requirement of the requested flutter frequency value F_req according to the judgment formula, if so, executing S3, if not, executing S4;

[0009] S3, temporarily storing the number of current step changes Nstep of the L9305 chip dither that meets the requirements, and each step time length Tstep of the L9305 chip dither corresponding to the number of current step changes Nstep;

[0010] S4, determine whether the indexing is completed, if completed, execute S5, if not completed, repeat S2 and S3 until the indexing is completed;

[0011] S5, obtaining multiple current step change numbers Nstep in S3, and finding out the maximum current step change number Nstep among the multiple current step change numbers Nstep, and then obtaining each step time length Tstep corresponding to the maximum current step change number Nstep;

[0012] S6, calculate the current change Istep of each step of the L9305 chip vibration according to the sent amplitude Amplitude and the maximum current step change number Nstep in S5;

[0013] S7, synchronize the spi instruction, and input the maximum current step change number Nstep, the length of each step time Tstep corresponding to the maximum current step change number Nstep, and the current change amount Istep of each step into the L9305 chip to realize the vibration control of the solenoid valve.

[0014] Therefore, the flutter control of the solenoid valve is achieved by first looking up the table and indexing to obtain the maximum current step change number Nstep, then the time length Tstep of each step corresponding to the maximum current step change number Nstep, and finally obtaining the current change amount Istep for each step. Compared with the control method of the existing hardware improvement and PID control strategy, this method can accurately control the driving current and optimize the control algorithm. In addition, without increasing the additional hardware cost, it can improve the accuracy of the flutter control and correction control of the solenoid valve, thereby improving the stability of the system and the service life of the solenoid valve.

[0015] Furthermore, in S1, the calculation formula for the theoretically calculated flutter frequency value F_theo is:

[0016]

[0017] The unit of Nstep is Hz.

[0018] Furthermore, S2, the judgment formula is:

[0019] F_req(1-K1)≤F_theo≤F_req(1+K1);

[0020] Among them: K1 is the preset value.

[0021] Furthermore, in S6, the calculation formula for each step current change Istep is:

[0022]

[0023] Among them: Amplitude unit is mA.

[0024] Further, in S1, the theoretical calculated dither frequency value F_theo is obtained by looking up the dither frequency control parameter table; in S3, the current step change number Nstep and the time length of each step Tstep are both obtained by looking up the dither frequency control parameter table.

[0025] A correction method for a solenoid valve flutter control method based on an L9305 chip comprises the following steps:

[0026] Sd, obtain the corrected current amplitude Amp_actual_corr according to the current amplitude Amp_actual, the requested dither frequency value F_req and the dither frequency threshold F_th of the dynamic compensation logic;

[0027] Se, obtain the corrected current amplitude Amp_actual_corr according to the current amplitude Amp_actual;

[0028] Sf, determine whether the corrected current amplitude Amp_actualA is less than the requested amplitude Amp_rep, if so, each step current change Istep increases by 1 unit, if not, each step current change Istep decreases by 1 unit;

[0029] Sg, obtain Istep_cal, request flutter frequency value F_req, flutter frequency threshold F_th of dynamic compensation logic and each step current change Istep, and judge whether each step current change Istep meets the requirements according to the judgment formula, if so, execute Sh;

[0030] Sh, judge whether each step current change Istep meets the requirements according to the judgment formula, if yes, execute Si;

[0031] Si. Input each step current change Istep into the L9305 chip to achieve correction control of the solenoid valve.

[0032] Furthermore, in Sb, the calculation formula of the current amplitude Amp_actual is:

[0033] Amp_actual = I max -I min ;

[0034] Among them: current amplitude Amp_actual maximum current value I max , minimum current value I min The average unit is mA.

[0035] Furthermore, in Sd, the calculation formula of the corrected current amplitude Amp_actual_corr is:

[0036]

[0037] In Se, the calculation formula of the corrected current amplitude Amp_actual_corr is:

[0038] Amp_actual_corr=Amp_actual.

[0039] Furthermore, in Sg, the judgment formula is:

[0040]

[0041] Among them: K2 is the preset value.

[0042] Furthermore, in Sh, the judgment formula is:

[0043] 0≤Istep≤255.

[0044] The beneficial effects of the present invention are as follows:

[0045] The present invention realizes the flutter control of the solenoid valve by first looking up a table and indexing to obtain the maximum current step change number Nstep, then the time length Tstep of each step corresponding to the maximum current step change number Nstep, and finally obtaining the current change amount Istep of each step. Compared with the control method of the existing hardware improvement and PID control strategy, this method can accurately control the driving current and optimize the control algorithm. In addition, without increasing the additional hardware cost, it can improve the accuracy of the flutter control and correction control of the solenoid valve, thereby improving the stability of the system and the service life of the solenoid valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a flow chart of the electromagnetic valve flutter control method based on L9305 chip of the present invention;

[0047] Figure 2 It is a flow chart of a correction method of the electromagnetic valve flutter control method based on the L9305 chip of the present invention;

[0048] Figure 3 It is a schematic diagram of the beat time axis of the correction method of the solenoid valve vibration control method based on the L9305 chip of the present invention. DETAILED DESCRIPTION

[0049] The specific implementation of the present invention will be described below in conjunction with the accompanying drawings.

[0050] like Figure 1 As shown, a solenoid valve vibration control method based on the L9305 chip includes the following steps:

[0051] S1, obtaining a requested dither frequency value F_req (Frequency request) and a theoretically calculated dither frequency value F_theo of a required dither control solenoid valve;

[0052] S2, obtaining the requested flutter frequency value F_req and the theoretically calculated flutter frequency value F_theo in S1, and judging whether the theoretically calculated flutter frequency value F_theo meets the interval range requirement of the requested flutter frequency value F_req according to the judgment formula, if so, executing S3, if not, executing S4;

[0053] S3, temporarily storing the number of current step changes Nstep of the L9305 chip dither that meets the requirements, and each step time length Tstep of the L9305 chip dither corresponding to the number of current step changes Nstep;

[0054] S4, determine whether the indexing is completed, if completed, execute S5, if not completed, repeat S2 and S3 until the indexing is completed;

[0055] S5, obtaining multiple current step change numbers Nstep in S3, and finding out the maximum current step change number Nstep among the multiple current step change numbers Nstep, and then obtaining each step time length Tstep corresponding to the maximum current step change number Nstep;

[0056] S6, calculate the current change Istep of each step of the L9305 chip vibration according to the sent amplitude Amplitude and the maximum current step change number Nstep in S5;

[0057] S7, synchronize the spi instruction, and input the maximum current step change number Nstep, the time length Tstep of each step corresponding to the maximum current step change number Nstep, and the current change amount Istep of each step into the L9305 chip to realize the flutter control of the solenoid valve. Therefore, the flutter control of the solenoid valve is realized by first looking up the table and indexing to obtain the maximum current step change number Nstep, then the time length Tstep of each step corresponding to the maximum current step change number Nstep, and finally obtaining the current change amount Istep of each step. Compared with the control method of the existing hardware improvement and PID control strategy, this method can accurately control the drive current and optimize the control algorithm. In addition, without increasing the additional hardware cost, the accuracy of the flutter control of the solenoid valve can be improved, thereby improving the stability of the system and the service life of the solenoid valve.

[0058] In other words, by looking up the table and indexing to obtain the maximum number of current step changes, and combining it with the length of each step time, the flutter frequency and amplitude of the solenoid valve can be accurately controlled. In this way, the solenoid valve current can be finely adjusted to ensure the accurate generation of the flutter signal; by dynamically adjusting the number of current step changes and the step time length, the real-time correction of the solenoid valve flutter behavior is achieved. This dynamic adjustment mechanism makes the control more flexible and can adapt to different working conditions and system changes; compared with existing hardware improvements and PID control strategies, this method can improve the response speed of the solenoid valve and reduce the problem of inaccurate flutter control caused by slow current changes. The rapid response capability is particularly important for control systems that require rapid adjustment; this method includes: real-time detection and correction of the solenoid valve current, which can promptly detect and adjust deviations in flutter control to ensure that the solenoid valve always works in the best state.

[0059] It should be noted that: 1. Since the theoretical calculated dither frequency value F_theo calculated by the current step change number Nstep and each step time length Tstep is consistent with the actual dither frequency value collected by the oscilloscope test, that is, no dither frequency compensation is required, it is more reasonable to first determine the current step change number Nstep and each step time length Tstep corresponding to the dither frequency, and then use the current step change number Nstep and the request value to calculate each step current change Istep, and then perform dynamic correction of the amplitude; on the contrary, if the dither request amplitude is calculated first, the corresponding parameters of the current step change number Nstep and each step time length Tstep are dynamically changed, which leads to the jitter of the theoretical dither frequency calculated by the current step change number Nstep and each step time length Tstep, which will make the dither control accuracy worse;

[0060] 2. The L9305 chip is a solenoid valve control chip, which has hardware closed-loop current control and vibration control functions;

[0061] 3. The current step change number Nstep ranges from [0, 31], which defines the number of current step changes within a quarter of the dither period;

[0062] 4. The range of each step time length Tstep is [0, 63], which defines the time length of each step in the dither waveform, that is, the time interval from one step to the next step;

[0063] 5. The range of each step current change Istep is [0, 255], which defines the current change of each step in the Di ther waveform;

[0064] 6. spi: Serial Peripheral Interface, serial peripheral interface, is a high-speed, full-duplex, synchronous communication bus.

[0065] In this embodiment, in S1, the calculation formula for the theoretically calculated flutter frequency value F_theo is:

[0066]

[0067] The unit of Nstep is Hz.

[0068] In this embodiment, at S2, the judgment formula is:

[0069] F_req(1-K1)≤F_theo≤F_req(1+K1);

[0070] Wherein: K1 is a preset value. For example, K1 = 5%, that is, as long as the found F_theo is within the required dither frequency ±5%, the corresponding current step change number Nstep and each step time length Tstep are both considered as effective values.

[0071] In this embodiment, in S6, the calculation formula of each step current change Istep is:

[0072]

[0073] Among them: Amplitude unit is mA.

[0074] In this embodiment, in S1, the theoretical calculated dither frequency value F_theo is obtained by looking up the dither frequency control parameter table; in S3, the current step change number Nstep and the time length of each step Tstep are both obtained by looking up the dither frequency control parameter table.

[0075] Table 1: Flutter frequency control parameter lookup table

[0076]

[0077]

[0078] like Figures 2 to 3 As shown, a correction method for the electromagnetic valve flutter control method based on the L9305 chip includes the following steps:

[0079] Sa, obtain the current of the solenoid valve, and determine whether the current of the solenoid valve reaches the specified beat. If it reaches the specified beat, execute Sb;

[0080] Sb, synchronously read the recovery current value of the L9305 chip, and calculate the maximum current value I read in a valve vibration cycle max , minimum current value I min , and then calculate the current amplitude Amp_actual obtained by L9305 chip;

[0081] Sc, obtain the requested flutter frequency value F_req of the required flutter control solenoid valve and the flutter frequency threshold F_th of the dynamic compensation logic, and determine the relationship between the two. If F_req>F_th, execute Sd; if F_req≤F_th, execute Se;

[0082] Sd, obtain the corrected current amplitude Amp_actual_corr according to the current amplitude Amp_actual, the requested dither frequency value F_req and the dither frequency threshold F_th of the dynamic compensation logic;

[0083] Se, obtain the corrected current amplitude Amp_actual_corr according to the current amplitude Amp_actual;

[0084] Sf, determine whether the corrected current amplitude Amp_actualA is less than the requested amplitude Amp_rep, if so, each step current change Istep increases by 1 unit, if not, each step current change Istep decreases by 1 unit;

[0085] Sg, obtain Istep_cal, request flutter frequency value F_req, flutter frequency threshold F_th of dynamic compensation logic and each step current change Istep, and judge whether each step current change Istep meets the requirements according to the judgment formula, if so, execute Sh;

[0086] Sh, judge whether each step current change Istep meets the requirements according to the judgment formula, if yes, execute Si;

[0087] Si. Input each step current change Istep into the L9305 chip to achieve correction control of the solenoid valve.

[0088] It should be noted that: 1. In Sa, as shown in Figure 1, reaching the specified beat means that the code corresponding to the correction method is looped in the 200us cycle Task and executed at a fixed beat, and the spi current is collected at each beat time point. Uneven time beat points are more likely to hit the maximum current and the minimum current;

[0089] 2. In Sc, when F_req>F_theo (i.e., high-frequency dithering), it is not easy to hit the maximum current and the minimum current, resulting in a smaller amplitude calculation. At this time, coefficient compensation is required;

[0090] 3. In Sf, control the range of dynamic correction parameters to avoid significant deviations from theoretical calculation results;

[0091] 4. F_th is the flutter frequency threshold of the dynamic compensation logic, in Hz;

[0092] 5. Istep_cal, Istep calibration, used to limit the range of Istep in amplitude dynamic range adjustment and can be used for calibration;

[0093] 6. Amp_actual_corr: Actual correction of amplitude, actual correction amplitude.

[0094] In this embodiment, in Sb, the calculation formula of the current amplitude Amp_actual is:

[0095] Amp_actual = I max -I min ;

[0096] Among them: current amplitude Amp_actual maximum current value I max , minimum current value I min The average unit is mA.

[0097] In this embodiment, in Sd, the calculation formula of the corrected current amplitude Amp_actual_corr is:

[0098]

[0099] In Se, the calculation formula of the corrected current amplitude Amp_actual_corr is:

[0100] Amp_actual_corr=Amp_actual.

[0101] In this embodiment, in Sg, the judgment formula is:

[0102]

[0103] Wherein: K2 is a preset value, for example, K2 = 10%.

[0104] In this embodiment, in Sh, the judgment formula is:

[0105] 0≤Istep≤255.

[0106] To summarize, the present invention realizes the flutter control of the solenoid valve by first looking up a table and indexing to obtain the maximum current step change number Nstep, then the time length Tstep of each step corresponding to the maximum current step change number Nstep, and finally obtaining the current change amount Istep for each step. Compared with the control method of the existing hardware improvement and PID control strategy, this method can accurately control the driving current and optimize the control algorithm. In addition, without increasing the additional hardware cost, it can improve the accuracy of the flutter control and correction control of the solenoid valve, thereby improving the stability of the system and the service life of the solenoid valve.

[0107] The above description is an explanation of the present invention, not a limitation of the present invention. The scope of the present invention is defined in the claims. Any form of modification may be made within the scope of protection of the present invention.

Claims

1. A solenoid valve flutter control method based on L9305 chip, characterized in that: The following steps are involved: S1, obtaining a requested dither frequency value F_req and a theoretical calculated dither frequency value F_theo of a required dither control solenoid valve; S2, obtaining the requested flutter frequency value F_req and the theoretically calculated flutter frequency value F_theo in S1, and judging whether the theoretically calculated flutter frequency value F_theo meets the interval range requirement of the requested flutter frequency value F_req according to the judgment formula, if so, executing S3, if not, executing S4; S3, temporarily storing the number of current step changes Nstep of the L9305 chip dither that meets the requirements, and each step time length Tstep of the L9305 chip dither corresponding to the number of current step changes Nstep; S4, determine whether the indexing is completed, if completed, execute S5, if not completed, repeat S2 and S3 until the indexing is completed; S5, obtaining multiple current step change numbers Nstep in S3, and finding out the maximum current step change number Nstep among the multiple current step change numbers Nstep, and then obtaining each step time length Tstep corresponding to the maximum current step change number Nstep; S6, calculate the current change Istep of each step of the L9305 chip vibration according to the sent amplitude Amplitude and the maximum current step change number Nstep in S5; S7, synchronize the spi instruction, and input the maximum current step change number Nstep, the length of each step time Tstep corresponding to the maximum current step change number Nstep, and the current change amount Istep of each step into the L9305 chip to realize the vibration control of the solenoid valve.

2. The solenoid valve vibration control method based on the L9305 chip as claimed in claim 1, characterized in that: In S1, the calculation formula for the theoretical flutter frequency value F_theo is: The unit of Nstep is Hz.

3. The solenoid valve flutter control method based on the L9305 chip as claimed in claim 1, characterized in that: S2, the judgment formula is: F_req(1-K1)≤F_theo≤F_req(1+K1); Among them: K1 is the preset value.

4. The solenoid valve vibration control method based on the L9305 chip as claimed in claim 1, characterized in that: In S6, the calculation formula for each step current change Istep is: Among them: Amplitude unit is mA.

5. The solenoid valve vibration control method based on the L9305 chip as claimed in claim 1, characterized in that: In S1, the theoretical calculated flutter frequency value F_theo is obtained by looking up the flutter frequency control parameter table; In S3, the current step change number Nstep and the time length of each step Tstep are obtained by looking up the dither frequency control parameter table.

6. A correction method for the electromagnetic valve flutter control method based on the L9305 chip as claimed in any one of claims 1 to 5, characterized in that: The following steps are involved: Sa, obtain the current of the solenoid valve, and determine whether the current of the solenoid valve reaches the specified beat. If it reaches the specified beat, execute Sb; Sb, synchronously read the recovery current value of the L9305 chip, and calculate the maximum current value I read in a valve tremor cycle max , minimum current value I min , and then calculate the current amplitude Amp_actual obtained by L9305 chip; Sc, obtain the requested flutter frequency value F_req of the required flutter control solenoid valve and the flutter frequency threshold F_th of the dynamic compensation logic, and determine the relationship between the two. If F_req>F_th, execute Sd; if F_req≤F_th, execute Se; Sd, obtain the corrected current amplitude Amp_actual_corr according to the current amplitude Amp_actual, the requested dither frequency value F_req and the dither frequency threshold F_th of the dynamic compensation logic; Se, obtain the corrected current amplitude Amp_actual_corr according to the current amplitude Amp_actual; Sf, determine whether the corrected current amplitude Amp_actualA is less than the requested amplitude Amp_rep, if so, each step current change Istep increases by 1 unit, if not, each step current change Istep decreases by 1 unit; Sg, obtain Istep_cal, request flutter frequency value F_req, flutter frequency threshold F_th of dynamic compensation logic and each step current change Istep, and judge whether each step current change Istep meets the requirements according to the judgment formula, if so, execute Sh; Sh, judge whether each step current change Istep meets the requirements according to the judgment formula, if yes, execute Si; Si. Input each step current change Istep into the L9305 chip to achieve correction control of the solenoid valve.

7. The correction method of the electromagnetic valve flutter control method based on the L9305 chip as claimed in claim 6, characterized in that: In Sb, the calculation formula of the current amplitude Amp_actual is: Amp_actual=I max -I min ; Among them: current amplitude Amp_actual maximum current value I max , minimum current value I min The average unit is mA.

8. The correction method of the electromagnetic valve flutter control method based on the L9305 chip as claimed in claim 6, characterized in that: In Sd, the calculation formula of the corrected current amplitude Amp_actual_corr is: In Se, the calculation formula of the corrected current amplitude Amp_actual_corr is: Amp_actual_corr=Amp_actual.

9. The correction method of the electromagnetic valve flutter control method based on the L9305 chip as claimed in claim 6, characterized in that: In Sg, the judgment formula is: Among them: K2 is the preset value.

10. The electromagnetic valve flutter control method and correction method based on the L9305 chip as claimed in claim 1, characterized in that: In Sh, the judgment formula is: 0≤Istep≤255.

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