Self-learning method for a pressure sensor

Abstract

The application discloses a self-learning method of a pressure sensor, and comprises the following self-learning method: calculating a system pressure control correction pressure; judging a system pressure self-learning condition and calculating the pressure; and calculating a system electromagnetic valve target current. The application belongs to the technical field of power assembly hydraulic control systems, and particularly relates to a self-learning method of a pressure sensor, which can obtain a more accurate system electromagnetic valve target current without changing system hardware and avoiding complex fitting algorithms.

Description

Technical Field

[0001] This invention belongs to the technical field of powertrain hydraulic control system, specifically referring to a self-learning method for pressure sensors. Background Technology

[0002] In the hydraulic control system of a CVT (Constantly Variable Transmission), the control of the solenoid valves of the hydraulic valve plate system is based on the target current obtained by looking up tables from signals such as the actual system pressure, target system pressure, oil temperature, and system valve flow rate read by sensors. Alternatively, the pressure-current PI characteristics at different oil temperatures can be offline fitted using a binomial formula, but this method is relatively complex. Furthermore, errors caused by the interchangeability and stability of the pressure sensors themselves, as well as residual flow from the hydraulic valve plate, can lead to inaccurate calculations of the target current, resulting in inaccurate control of the solenoid valves and thus affecting the control performance of the hydraulic system. Summary of the Invention

[0003] In order to overcome the shortcomings of the prior art, the present invention provides a self-learning method for pressure sensors, which can obtain a more accurate target current of the system solenoid valve without changing the system hardware and avoiding complex fitting algorithms.

[0004] The technical solution adopted by this invention is as follows: This invention provides a self-learning method for a pressure sensor, specifically including the following self-learning method:

[0005] (1) Calculate the pressure control correction pressure of the system;

[0006] (2) System pressure self-learning condition judgment and pressure calculation;

[0007] (3) Calculate the target current of the solenoid valve in the system.

[0008] Preferably, the calculation method in step (1) is as follows:

[0009] The system target pressure minus the actual system pressure is used as the base value for the correction pressure, i.e.:

[0010] ΔP0=P G -P A

[0011] Where ΔP0 is the baseline value of the system pressure control correction pressure, P G For the system target pressure, P A This represents the actual pressure of the system.

[0012] The system pressure is controlled using PI closed-loop control. The P and I coefficients are calculated from a table based on the system target pressure, oil temperature, actual system pressure change rate, and system target pressure change rate.

[0013]

[0014] Δa i =f Δi (R G R A );

[0015] a p =f p (P G ,T);

[0016]

[0017] in, I is the basic coefficient, T is the oil temperature, and Δa i Let I be the correction factor, and R be the correction factor. A R represents the actual rate of change of system pressure. G Let a be the rate of change of the system target pressure. p Let a be the P coefficient. i The coefficient is I.

[0018] The P and I coefficients are multiplied by the base values ​​respectively to obtain the P correction pressure and I correction pressure. The sum of the two is then subject to maximum and minimum limits to obtain the system pressure control correction pressure, i.e.:

[0019] ΔP p =ΔP0·a p ;

[0020] ΔA i =ΔP0·a i ;

[0021] ΔP iΔt =ΔA i ·Δt;

[0022] ΔP i =f lim (∑ΔP iΔt );

[0023] ΔP=f lim (ΔP p +ΔP i );

[0024] P GC =P G +ΔP;

[0025] Where, ΔP p For the pressure correction P, ΔAi For the correction value of I, ΔP iΔt Corrected pressure per unit time, ΔP i Let I be the correction pressure, t be the unit process time, ΔP be the system pressure control correction pressure, and P be the system pressure control correction pressure. GC The target positive pressure for system pressure control.

[0026] Preferably, the calculation method in step (2) is as follows:

[0027] When the oil temperature, system target pressure, and absolute value of the system target pressure change rate are within the set range, and the average value of the system pressure control correction pressure is calculated within the set time, that is, ∑ calculated system pressure control correction pressure / number of calculations;

[0028] Count += 1;

[0029] Sum = ∑ΔP;

[0030] E0 = f lim (Sum / Count);

[0031] If the set time is exceeded or the oil temperature, system target pressure, or absolute value of the system target pressure change rate are outside the set range, the corrected pressure average value is stored in memory. Once the oil temperature, system target pressure, or absolute value of the system target pressure change rate are within the set range, the corrected pressure average value is calculated again and added to the previously stored average value to obtain the learned pressure compensation value, i.e., the system pressure self-learning pressure.

[0032] P L =f lim (Sum / Count)+E0;

[0033] Among them, P L The system pressure is a self-learning pressure; this pressure compensation value can be saved and fixed in memory, which is easy to implement and can be used as a method of automatic adjustment.

[0034] Preferably, the calculation method in step (3) is as follows:

[0035] Each calculated corrected pressure is added to the system target pressure to obtain the system pressure control target pressure. This target pressure is then added to the system pressure self-learning pressure. The sum of these values ​​is used to find the system IP characteristic table to obtain the system solenoid valve target current base value.

[0036]

[0037] in, This is the baseline value for the target current of the system's solenoid valve;

[0038] The sum of the values ​​is used to find the target current correction value for the system solenoid valve by referring to the system IP characteristic correction table.

[0039] ΔI G =f Δip (P GC +P L Q L );

[0040] Where, ΔI G This is the target current correction value for the system's solenoid valve;

[0041] Adding the current correction value to the base current value yields the target current for the system solenoid valve.

[0042]

[0043] Among them, I G The target current value for the system solenoid valve is used to control the system solenoid valve.

[0044] This method continuously learns and evaluates existing performance, automatically adjusting the system pressure self-learning pressure value to improve its own quality and reduce the impact of random errors caused by downtime.

[0045] Furthermore, in step (2), the system self-learning flag is set to true when all four conditions are met simultaneously, and after a set delay (the flag is set after the duration of the condition is met is greater than or equal to a certain time, otherwise it remains reset) for a set time (preset 2s); when one of the four conditions is not met or the set delay is not met, the system self-learning flag is reset to false. The four conditions are as follows:

[0046] 1. T is within a set range, the boundary of which can be calibrated, and the preset boundary is [30, 100]℃;

[0047] 2. P G Within a set range, the boundaries of which can be defined, with the default boundary being [5, 40] bar;

[0048] 3. R G The absolute value is less than the set value, which can be calibrated and is preset to 5 bar / s;

[0049] 4. Duration t of the system's self-learning flag position L (t L =Count·Δt, where Count is the counter) is less than the set value, which can be calibrated and is preset to 15s.

[0050] The beneficial effects achieved by adopting the above structure are as follows: This solution provides a self-learning method for pressure sensors, with the following beneficial effects:

[0051] (1) Without changing the system hardware and performing complex fitting calculations, the system pressure can be compensated by PI closed-loop control, and the system pressure can be compensated by algorithm logic.

[0052] (2) The pressure compensation value can be saved and fixed in memory, which is easy to implement and can be used as a method of automatic adjustment.

[0053] (3) Through continuous self-learning and evaluation of existing excellence, the system automatically modifies the self-learning pressure value of the system pressure to improve its own quality and reduce the impact of random errors caused by shutdown. Attached Figure Description

[0054] Figure 1 The flowchart illustrates the calculation of system pressure control correction pressure, system pressure control target pressure, system pressure self-learning pressure, and system solenoid valve target current for a pressure sensor self-learning method proposed in this invention.

[0055] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. Detailed Implementation

[0056] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0057] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0058] like Figure 1 As shown, the present invention provides a self-learning method for a pressure sensor, the self-learning method being as follows:

[0059] 1. Calculate the system pressure control correction pressure

[0060] The system pressure is controlled by PI closed-loop control by subtracting the actual system pressure from the target system pressure as the base value for correction pressure. The P and I coefficients are calculated by referring to tables based on the target system pressure, oil temperature, and the rate of change of the actual system pressure. The P and I coefficients are multiplied by the base value to obtain the P correction pressure and I correction pressure, respectively. The sum of the two is then subject to maximum and minimum limits to obtain the system pressure control correction pressure.

[0061] 2. System pressure self-learning condition judgment and pressure calculation

[0062] When the oil temperature, system target pressure, and absolute value of the system target pressure change rate are within the set range, and within the set time, the average value of the system pressure control correction pressure is calculated (i.e., Σ calculated system pressure control correction pressure / number of calculations). If the set time is exceeded or the oil temperature, system target pressure, and absolute value of the system target pressure change rate are outside the set range, the average value of the correction pressure is stored in memory. When the oil temperature, system target pressure, and absolute value of the system target pressure change rate are within the set range, the average value of the correction pressure is calculated again, and then added to the previously stored average value to obtain the learned pressure compensation value (system pressure self-learning pressure). This pressure compensation value can be saved and fixed in memory, which is easy to implement and can be used as a strategy for automatic adjustment.

[0063] 3. Calculate the target current of the solenoid valve in the system.

[0064] Each calculated corrected pressure is added to the system target pressure to obtain the system pressure control target pressure. This target pressure is then added to the system pressure self-learning pressure. The sum of these values ​​is compared with the oil temperature and consulted from the system IP characteristic table to obtain the system solenoid valve target current baseline value. This final value is then compared with the system valve flow rate and consulted from the system IP characteristic correction table to obtain the system solenoid valve target current correction value. Finally, the current baseline value is added to the current correction value to obtain the system solenoid valve target current, thereby controlling the system solenoid valve. This strategy continuously learns and evaluates its existing performance, automatically adjusting the system pressure self-learning pressure value to improve its quality and reduce the impact of errors caused by random downtime.

[0065] In practical use:

[0066] This method is implemented in the TCU transmission controller;

[0067] The input signal includes the actual system pressure P. A [0, 70] bar, system target pressure P G [0, 70] bar, actual system pressure change rate R A [-1000, 1000] bar / s, system target pressure change rate R G [-1000, 1000] bar / s, system valve flow rate QL Given an oil flow rate of [0, 25] L / min and an oil temperature of [-50, 150] °C, the system pressure control target pressure P is calculated. GC System pressure control correction pressure ΔP, system pressure self-learning pressure P L Then, by referring to tables, the target current I of the system solenoid valve, which is closer to the actual value, is calculated. G The specific steps are described below with attached diagrams (the engine and oil pump are in normal operating condition).

[0068] 1. Calculate the system pressure control correction pressure ΔP and the system pressure control target pressure P. GC ;

[0069] 1. Implement PI closed-loop control on the system pressure and calculate ΔP;

[0070] a) System pressure control correction pressure baseline value ΔP0=P G -P A ;

[0071] b) P coefficient a p =f p (P G ,T), where: f p (x, y) is a lookup table for the P-coefficient Map1. The Map table can be calibrated, and the default table is as follows:

[0072] y / x 6.000 12.000 18.000 24.000 30.000 36.000 42.000 48.000 54.000 60.000 -30.000 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 -20.000 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 -10.000 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.000 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 20.000 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 40.000 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 60.000 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 80.000 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 100.000 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 120.000 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500

[0073] P-coefficient Map Table 1 (x: P) G ,y:T)

[0074] c) I Basic Coefficient I Correction coefficient Δa i =f Δi (R G R A ), I coefficient in: To look up the I basic coefficient Map table 2, the preset table is as follows:

[0075] y / x 6.000 12.000 18.000 24.000 30.000 36.000 42.000 48.000 54.000 60.000 -30.000 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 -20.000 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 -10.000 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.000 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 20.000 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 40.000 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 60.000 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 80.000 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 100.000 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 120.000 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050

[0076] I. Basic Coefficient Map Table 2 (x: P) G ,y:T)

[0077] f Δi (x, y) is a lookup table for the I correction coefficient Map 3, with the following preset table:

[0078] y / x -100.000 -50.000 -25.000 -10.000 -5.000 5.000 10.000 25.000 50.000 100.000 -100.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 -50.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 -25.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 -10.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 -5.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 5.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 10.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 25.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 50.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 100.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000

[0079] I. Correction Coefficient Map Table 3 (x:R) Gy:R Δ )

[0080] d) Corrected pressure ΔP p =ΔP0·a p ;

[0081] e)I Correction value ΔA i =ΔP0·a i The pressure correction per unit time is ΔP. iΔt =ΔA i ·Δt, I corrected pressure ΔP i =f lim (∑ΔP iΔt Where: Δt is the unit process time (this method uses a process time of 0.01s), f lim (x) represents the maximum and minimum value constraint processing. The maximum and minimum boundaries can be calibrated. The default constraint boundary is [-5, 5] bar.

[0082] f) Calculate the system pressure control correction pressure: ΔP = f lim (ΔP p +ΔP i ); The preset limit boundary is [-5, 5] bar.

[0083] 2. Calculate the target pressure P for system pressure control. GC :P GC =P G +ΔP;

[0084] II. Calculate the self-learning pressure P of the system pressure. L :

[0085] 1. The system self-learning flag is set to true when all four of the following conditions are met simultaneously, and after a set delay (the flag is set after the duration of the condition is met is greater than or equal to a certain time, otherwise it remains reset) for a set time (preset 2 seconds); when one of the four conditions is not met or the set delay is not met, the system self-learning flag is reset to false. The four conditions are as follows:

[0086] a) T is within a set range, the boundary of which can be calibrated, and the preset boundary is [30, 100]℃;

[0087] b) P G Within a set range, the boundaries of which can be calibrated, with the preset boundary being [5, 40] bar;

[0088] c) R G The absolute value is less than the set value, which can be calibrated and is preset to 5 bar / s;

[0089] d) Duration t of the system's self-learning flag position L (tL =Count·Δt, where Count is the counter) is less than the set value, which can be calibrated and is preset to 15s.

[0090] 2. When the system self-learning flag is set, the counter Count+=1, causing the system pressure control correction pressure ΔP to accumulate (denoted as Sum=∑ΔP). The average value Sum / Count is calculated, and the average value is subject to maximum and minimum limits to obtain E0, i.e., E0=f lim (Sum / Count), set the preset limit boundary to [-5, 5] bar; at the falling edge of the system self-learning flag (from the moment the flag is set to the moment of reset), E0 is stored in EEPROM (Electrically Erasable Programmable Read-Only Memory), which can be read from EEPROM during the initialization process of the program power-on; and after the system self-learning flag is reset, the counter Count = 0 and Sum = 0.

[0091] 3. Calculate P L :P L It equals the sum of the maximum and minimum limits of the average value obtained from each learning session and the value stored in the previous session, i.e., P. L =f lim (Sum / Count)+E0, the default limit boundary is [-5, 5] bar.

[0092] III. Calculate the target current I of the solenoid valve in the system. G :

[0093] 1. Base value I of the target current of the system solenoid valve G0 =f ip (P GC +P L (T). Where: f ip (x, y) is a lookup table for system IP characteristic Map 4, with the following default table:

[0094]

[0095] System IP Feature Map Table 4 (x:P) GC +P L ,y:T)

[0096] 2. System solenoid valve target current correction value ΔI G =f Δip (P GC +P L Q L ). Where: f Δip (x, y) is the lookup table for system IP characteristic correction values ​​in Map 5. The default table is as follows:

[0097]

[0098] System IP Feature Correction Value Map Table 5 (x: P GC +P L ,y:QL)

[0099] 3. Calculation After being constrained by maximum and minimum values, the preset limit boundary is [0, 1.2]A, and the output is... This allows for real-time and precise control of the system's solenoid valves.

[0100] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0101] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0102] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. A self-learning method for a pressure sensor, characterized in that: Including the following self-learning methods: (1) Calculate the pressure control correction pressure of the system; (2) System pressure self-learning condition judgment and pressure calculation; (3) Calculate the target current of the system solenoid valve; The calculation method in step (2) is as follows: When the oil temperature, system target pressure, and absolute value of the system target pressure change rate are within the set range, and the average value of the system pressure control correction pressure is calculated within the set time, that is, Σ calculated system pressure control correction pressure / number of calculations; Count += 1; Sum = ∑ΔP; E0=f lim (Sum / Count); If the set time is exceeded or the oil temperature, system target pressure, or absolute value of the system target pressure change rate are outside the set range, the corrected pressure average value is stored in memory. Once the oil temperature, system target pressure, or absolute value of the system target pressure change rate are within the set range, the corrected pressure average value is calculated again and added to the previously stored average value to obtain the learned pressure compensation value, i.e., the system pressure self-learning pressure. P L =f lim (Sum / Count)+E0; Among them, P L The system pressure is a self-learning pressure; this pressure compensation value can be saved and fixed in memory, which is easy to implement and can be used as a method of automatic adjustment. The calculation method in step (3) is as follows: Each calculated corrected pressure is added to the system target pressure to obtain the system pressure control target pressure. This target pressure is then added to the system pressure self-learning pressure. The sum of these values ​​is used to find the system IP characteristic table to obtain the system solenoid valve target current base value. in, This is the baseline value for the target current of the system's solenoid valve; The sum of the values ​​is used to find the target current correction value for the system solenoid valve by referring to the system IP characteristic correction table. ΔI G =f Δip (P GC +P L ,Q L ); Where, ΔI G This is the target current correction value for the system's solenoid valve; Adding the current correction value to the base current value yields the target current for the system solenoid valve. Among them, I G The target current value for the system solenoid valve is used to control the system solenoid valve.

2. The self-learning method for a pressure sensor according to claim 1, characterized in that: The calculation method in step (1) is as follows: The system target pressure minus the actual system pressure is used as the base value for the correction pressure, i.e.: ΔP0=P G -P A Where ΔP0 is the baseline value of the system pressure control correction pressure, P G For the system target pressure, P A This represents the actual pressure of the system. The system pressure is controlled using PI closed-loop control. The P and I coefficients are calculated from a table based on the system target pressure, oil temperature, actual system pressure change rate, and system target pressure change rate. Δa i =f Δi (R G ,R A ); a p =f p (P G ,T); in, I is the basic coefficient, T is the oil temperature, and Δa i Let I be the correction factor, and R be the correction factor. A R represents the actual rate of change of system pressure. G Let a be the rate of change of the system target pressure. p Let a be the P coefficient. i The coefficient is I. The P and I coefficients are multiplied by the base values ​​respectively to obtain the P correction pressure and I correction pressure. The sum of the two is then subject to maximum and minimum limits to obtain the system pressure control correction pressure, i.e.: ΔP p =ΔP0·a p ; ΔA i =ΔP0·a i ; ΔP iΔt =ΔA i ·D t ; ΔP i =f lim (∑ΔP iΔt ); ΔP=f lim (ΔP p +ΔP i ); P GC =P G +ΔP; Where, ΔP p For the pressure correction P, ΔA i For the correction value of I, ΔP iΔt Corrected pressure per unit time, ΔP i Let I be the correction pressure, t be the unit process time, ΔP be the system pressure control correction pressure, and P be the system pressure control correction pressure. GC The target positive pressure for system pressure control.

3. The self-learning method for a pressure sensor according to claim 2, characterized in that: In step (2), the system self-learning flag is set to true when all four of the following conditions are met, and after a set delay time is set; when one of the four conditions is not met or the set delay is not met, the system self-learning flag is reset to false. The four conditions are as follows:

1. T is within a set range, the boundary of which can be calibrated, and the preset boundary is [30, 100]℃; 2. P G Within a set range, the boundaries of which can be defined, with the default boundary being [5, 40] bar; 3. R G The absolute value is less than the set value, which can be calibrated and is preset to 5 bar / s; 4. Duration t of the system's self-learning flag position L Less than the set value, where t L =Count·Δt, where Count is a counter, and this setting can be calibrated; the default value is 15s.

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