Electric automobile and torque slope self-adaptive control method and system thereof

Abstract

The invention discloses an electric automobile and a torque slope self-adaptive control method and system thereof, and belongs to the technical field of electric automobiles. The method comprises the steps that a driving style recognition signal, the accelerator pedal opening degree variable quantity and the motor target torque are obtained in real time; matching a regenerative braking torque change slope according to the driving style; when the torque of the motor enters a zero-crossing interval, the slope is switched to K1 or K2, and transition is carried out according to a continuous curve; and iteratively calculating the current motor demand torque according to a specific formula. Through stylized slope matching and zero-crossing region cooperative control, the problems of torque sudden change impact, poor driving style compatibility and zero-crossing region gear vibration in a traditional scheme are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric vehicles, and in particular relates to an electric vehicle and a method and system for adaptively controlling the torque slope thereof. Background Art

[0002] In traditional electric vehicle control systems, the vehicle control unit (VCU) directly outputs the target torque T according to the change in the accelerator pedal opening. tar To the motor control unit (MCU). When the driver changes the pedal opening quickly, such as when accelerating or releasing the pedal suddenly, the target torque T tar However, in this scenario, the sudden change in torque causes a sharp increase in the instantaneous stress of the transmission system, causing gear collision noise, and the driver feels a noticeable "setback" or "jump", especially during frequent starts and stops in congested urban conditions, which reduces comfort.

[0003] At the same time, during the gliding energy recovery process, drivers with different driving styles have different comfort and response speed requirements. For example, aggressive drivers have higher response speed requirements and expect a larger motor torque change slope; conservative drivers have higher comfort requirements and expect a smaller motor torque change slope.

[0004] When the motor torque switches between positive and negative values, the traditional control strategy has a blind spot in the zero-crossing area. The gear meshing clearance causes reverse backlash when the torque passes through zero, causing high-frequency vibration, which in turn shortens the life of the reducer and increases the noise inside the vehicle.

[0005] In summary, there is an urgent need for a control method that integrates driving style recognition, torque slope adaptation, and zero-crossing zone optimization to achieve a coordinated improvement in comfort, responsiveness, and reliability.

[0006] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the Invention

[0007] The purpose of the present invention is to provide an electric vehicle and a method and system for adaptively controlling the torque slope thereof, which can suppress the torque mutation impact, realize adaptive optimization of driving style, and eliminate the idle impact caused by transmission clearance.

[0008] To achieve the above object, the present invention provides a method for adaptively controlling the torque slope of an electric vehicle, comprising the following steps:

[0009] Step 1: Real-time acquisition of driving style recognition signal and accelerator pedal opening change d APP and motor target torque T tar ;

[0010] Step 2: Match the regenerative braking torque change slope according to the driving style;

[0011] Step 3: When the motor torque T req When entering the zero-crossing interval, the slope is switched to K1 or K2 and transitioned according to a continuous curve, where the motor torque change slope K is the change in the motor's required torque per unit time;

[0012] Step 4: Iteratively calculate the current motor required torque T according to the following formula req_t : , Among them, T req_t-1 The torque required by the motor at the previous moment.

[0013] Optionally, in step 1, the driving style classification criteria are:

[0014] Aggressive: historical accelerator pedal change rate (APR) average ≤ −30 Nm / s;

[0015] Standard type: −30 Nm / s < APR mean ≤ −10 Nm / s;

[0016] Conservative: APR average >−10Nm / s.

[0017] Optionally, in step 2, the motor torque variation slope K is fixedly set to:

[0018] The rising slope K1 = 600Nm / s, and the falling slope K2 = -600Nm / s, which has nothing to do with driving style.

[0019] Optionally, in step 2, matching the regenerative braking torque change slope according to the driving style includes: calling a preset regenerative braking torque change slope according to the driving style:

[0020] Aggressive type: rising slope K1 = 200 Nm / s, falling slope K2 = −200 Nm / s;

[0021] Standard type: rising slope K1 = 160 Nm / s, falling slope K2 = −160 Nm / s;

[0022] Conservative type: rising slope K1 = 120 Nm / s, falling slope K2 = −120 Nm / s.

[0023] Optionally, in step 2, matching the regenerative braking torque change slope according to the driving style further includes:

[0024] Limit the acceleration rate j during braking to 3 m / s 3The acceleration change rate j of the driving process is limited to 10 m / s 3 Inside;

[0025] According to the relationship between the motor torque change slope K and the acceleration change rate j: .

[0026] The reverse thrust motor torque change slope K is:

[0027] ,in is the wheel radius, is the transmission efficiency, For vehicle weight, is the reduction ratio.

[0028] Optionally, during the braking process, the motor torque change slope K is also calibrated according to the following rules:

[0029] For aggressive driving styles, the motor torque change slope is calibrated based on the upper and lower limits of the acceleration change rate j during braking;

[0030] For standard driving style, the motor torque change slope is calibrated to 80% of the aggressive driving style;

[0031] For a conservative driving style, the motor torque change slope is calibrated to 60% of that for an aggressive driving style.

[0032] Optionally, in step 3, the zero-crossing interval is set to [−35 Nm, 35 Nm].

[0033] Optionally, in step 3, when the motor torque T req When entering the zero-crossing interval, the slope is switched to K1 or K2, specifically including:

[0034] When the motor torque changes from positive to negative, at T req =0, K1=50Nm / s is used for transition;

[0035] When the motor torque changes from negative to positive, at T req =0, K2=-50Nm / s is used for transition.

[0036] The present invention also provides an electric vehicle torque slope adaptive control system, comprising:

[0037] Data acquisition unit, used to obtain driving style recognition signal and accelerator pedal opening change in real time APP and motor target torque T tar ;

[0038] a slope matching unit storing a driving style and slope mapping table for matching the regenerative braking torque change slope according to the driving style;

[0039] Zero-crossing control unit, used when the motor torque T req When entering the zero-crossing interval, the slope is switched to K1 or K2 and transitioned according to a continuous curve, where the motor torque change slope K is the change in the motor's required torque per unit time;

[0040] The torque iterative calculation unit uses a multi-core MCU (main frequency ≥ 200MHz) to iteratively calculate the current motor required torque T according to the following formula req_t :

[0041] , where T req_t-1 The torque required by the motor at the previous moment.

[0042] The present invention also provides an electric vehicle equipped with the electric vehicle torque slope adaptive control system.

[0043] Compared with the prior art, the electric vehicle and the torque slope adaptive control method and system thereof according to the present invention have the following advantages or beneficial effects:

[0044] The present invention matches the regenerative braking torque change slope according to the driving style, and through dynamic slope control, such as aggressive type K=±200Nm / s and conservative type K=±120Nm / s, limits the torque change rate to the physiological comfort threshold, thereby reducing gear impact noise.

[0045] Dynamically matches the slope based on historical accelerator pedal rate (APR) and independently calibrates driving and regenerative braking conditions. This reduces torque response delay for aggressive drivers and reduces acceleration rate under conservative conditions, improving comfort.

[0046] A sensitive range of [−35 Nm, 35 Nm] is defined, and the slope is switched to ±50 Nm / s when crossing zero, transitioning according to a continuous curve. This can eliminate the lost motion impact caused by transmission clearance, reduce the high-frequency vibration amplitude of the transmission system, and improve the fatigue life of the reducer test bench. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A schematic flow chart of an electric vehicle and a method for adaptively controlling torque slope thereof according to an embodiment of the present invention;

[0048] Figure 2 Schematic diagram of the torque change slope change process according to one embodiment of the present invention, wherein (a) is the K1 change process, and (b) is the K2 change process. DETAILED DESCRIPTION

[0049] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings 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 making creative efforts shall fall within the scope of protection of the present invention.

[0050] The terms "first," "second," "third," "fourth," and so forth (if any) in the description and claims of the present invention and in the accompanying drawings are used to distinguish similar items and are not necessarily used to describe a particular order or sequential sequence. It should be understood that the terms used in this manner are interchangeable where appropriate, such that the embodiments of the present invention described herein can be practiced in sequences other than those illustrated or described herein.

[0051] It should be understood that in various embodiments of the present invention, the size of the sequence number of each process does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0052] It should be understood that in the present invention, "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or apparatuses.

[0053] It should be understood that in the present invention, "multiple" refers to two or more. "And / or" is only a description of the association relationship of associated objects, indicating that three relationships can exist. For example, and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "Contains A, B and C", "Contains A, B, C" means that A, B, and C are all included, "Contains A, B or C" means that one of A, B, and C is included, and "Contains A, B and / or C" means that any one, any two, or any three of A, B, and C are included.

[0054] Depending on the context, "if" as used herein may be interpreted as "when" or "when" or "in response to determining" or "in response to detecting."

[0055] Existing electric vehicle torque control schemes suffer from torque shock, poor driving style compatibility, and gear shock in the zero-crossing zone. These issues can easily cause gear collision noise, reduce driving comfort, and produce high-frequency vibration, shortening the reducer's lifespan. This invention reduces this shock by dynamically matching the slope. Using a decreasing slope transition in the zero-crossing zone eliminates gear shock and reduces vibration amplitude.

[0056] The following specific embodiments are used to describe the technical solution of the present invention in detail. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0057] like Figure 1 As shown, the electric vehicle torque slope adaptive control method according to the preferred embodiment of the present invention includes the following steps:

[0058] Step 1: Real-time acquisition of driving style recognition signal and accelerator pedal opening change d APP and motor target torque T tar ;

[0059] Specifically, the driving style recognition signal is quantitatively classified based on historical accelerator pedal operation data, such as the average APR within a 10-second window. The driving style classification criteria are:

[0060] Aggressive: The average historical accelerator pedal change rate (APR) is ≤−30 Nm / s, with a high frequency of rapid pedal release and strong braking demand.

[0061] Standard type: −30 Nm / s < APR mean ≤ −10 Nm / s;

[0062] Conservative: Average APR > −10 Nm / s, smooth operation, and comfort first.

[0063] Using the historical average accelerator pedal change rate (APR) as the classification basis, the style recognition accuracy is improved, which improves the satisfaction rate of aggressive users' rapid deceleration needs and the comfort score of conservative users.

[0064] Furthermore, dual redundant pedal sensors are used to obtain accelerator pedal change signals with high signal acquisition accuracy, and the accelerator pedal change signals are transmitted via the CAN FD bus to ensure that the signals are real-time and reliable.

[0065] Accelerator pedal opening change d APP Refers to the rate of change of pedal opening per unit time. For example, if the pedal opening changes from 30% to 0% in 0.2s, then d APP =−150% / s, which is used to judge the driver's operating intention and serves as an auxiliary basis for slope switching.

[0066] The motor target torque Ttar is calculated by the VCU based on parameters such as pedal opening, vehicle speed, and battery SOC. For example, under braking intention: T tar =−150Nm (energy recovery); driving intention: T tar =300Nm (rapid acceleration).

[0067] Step 2: Match the regenerative braking torque change slope according to the driving style;

[0068] It should be noted that in step 2, the preset regenerative braking torque change slope is called according to the driving style, including:

[0069] Aggressive type: rising slope K1 = 200 Nm / s, falling slope K2 = −200 Nm / s, response priority;

[0070] Standard: Ascending slope K1 = 160 Nm / s, descending slope K2 = −160 Nm / s, balancing comfort and responsiveness;

[0071] Conservative: Ascending slope K1 = 120 Nm / s, descending slope K2 = −120 Nm / s, prioritizing comfort and minimizing impact.

[0072] Step 3: When the motor torque T req When entering the zero-crossing interval, switch the slope to K1 or K2 and transition according to the continuous curve, such as Figure 2 As shown, the motor torque change slope K is the change in the motor required torque per unit time;

[0073] Step 4: Iteratively calculate the current motor required torque T according to the following formula req_t :

[0074] , where T req_t-1 It should be noted that there are three cases for the motor torque slope adaptive adjustment: the current motor target torque T tar_t The motor torque T required at the previous moment req_t-1 When the difference is greater than the motor torque rising slope, the motor demand torque T at the current moment req_t T req_t-1 Add the motor torque rising slope K1; when T tar_t With T req_t-1 When the difference is less than the motor torque decrease slope K2, T req_t T req_t-1 Add K2; when T tar_t With T req_t-1 When the difference is between the motor torque decreasing slope and the motor torque increasing slope, it means that T req_t-1 Approaching T tar_t, the motor demand torque remains unchanged.

[0075] By acquiring the driving style signal and the target torque in real time and dynamically matching the slope, the impact of torque mutation is reduced. By switching the slope in the zero-crossing interval and coordinating the continuous curve transition, the gear collision noise is eliminated. APP The slope is adjusted in real time, shortening the response delay of aggressive drivers and reducing the acceleration change rate in conservative working conditions.

[0076] In an embodiment of the present invention, in driving processes such as overtaking scenarios where a quick response is required and the acceleration change rate threshold is relatively high, the motor torque change slope K is fixedly set to: rising slope K1 = 600 Nm / s, falling slope K2 = -600 Nm / s under driving conditions, regardless of driving style.

[0077] During the torque slope calibration process, in order to prevent the torque response of the regenerative braking process from affecting the torque response of the driving process, the regenerative braking torque change slope and the driving torque change slope need to be calibrated separately. In step 2 of the embodiment of the present invention, matching the regenerative braking torque change slope according to the driving style also includes:

[0078] Limit the acceleration rate j during braking to 3 m / s 3 The acceleration change rate j of the driving process is limited to 10m / s 3 To avoid causing serious discomfort to the driver, the motor efficiency is not considered during calibration;

[0079] According to the relationship between the motor torque change slope K and the acceleration change rate j: ,

[0080] The reverse thrust motor torque change slope K is:

[0081] ,in is the wheel radius, is the transmission efficiency, For vehicle weight, is the reduction ratio.

[0082] Specifically, set r = 0.35m (wheel radius), η = 0.92 (transmission efficiency), m = 1800kg (vehicle weight), i = 9.5 (reduction ratio), j's braking limit 3m / s³, and its driving limit 10m / s³. For the aggressive braking type: .

[0083] In the embodiment of the present invention, during the braking process, the motor torque change slope K is also calibrated according to the following rules:

[0084] For aggressive driving styles, to meet the response speed requirements, the motor torque change slope is calibrated based on the upper and lower limits of the acceleration change rate j during the braking process;

[0085] For a standard driving style, balancing comfort and drivability, the motor torque change slope is calibrated to 80% of an aggressive driving style;

[0086] For conservative driving styles, in order to meet the driver's higher comfort needs, the motor torque change slope is calibrated to 60% of the aggressive driving style.

[0087] Taking the aggressive slope as the benchmark (100%), the standard / conservative types are scaled at 80% / 60%, shortening the calibration time. OTA remote updates of slope parameters are also supported to adapt to driving habits in different regions.

[0088] In an embodiment of the present invention, the calibrated motor torque change slope is applicable to the non-zero-crossing interval of the motor torque. When the motor torque changes from positive drive to negative recovery, or returns from the recovery state to the drive state, it will experience a "torque zero-crossing" process. In this process, the motor torque briefly passes through zero. At this time, the gear transmission system may cause gear shock due to the effect of the transmission clearance, resulting in vibration and noise in the transmission system, affecting the smoothness and driving experience of the entire vehicle and the life of the reducer. Therefore, in the energy recovery control strategy, it is necessary to reasonably control the torque zero-crossing process to reduce gear shock and improve the smoothness and comfort of the system. The motor torque range of -35 Nm / s to 35 Nm / s is set as the torque zero-crossing interval. When the torque is 0, K1 is 50Nm / s and K2 is -50Nm / s. The change process of the torque change slopes K1 and K2 is as follows Figure 2 (a) (b) In addition, the interval [−35 Nm, 35 Nm] corresponds to the gear transmission lost motion angle ±0.15∘, which can reduce the impact risk area and extend the fatigue life of the reducer.

[0089] In the embodiment of the present invention, in step 3, when the motor torque T req When entering the zero-crossing interval, the slope is switched to K1 or K2, specifically including:

[0090] When the motor torque changes from positive to negative (driving → braking), at T req =0, K1=50Nm / s is used for transition;

[0091] When the motor torque changes from negative to positive (braking → driving), at T req =0, K2=-50Nm / s is used for transition.

[0092] The present invention also provides an embodiment of a torque slope adaptive control system for an electric vehicle, comprising:

[0093] Data acquisition unit, used to obtain driving style recognition signal and accelerator pedal opening change in real time APP and motor target torque T tar ;

[0094] a slope matching unit storing a driving style and slope mapping table for matching the regenerative braking torque change slope according to the driving style;

[0095] Zero-crossing control unit, used when the motor torque T req When entering the zero-crossing interval, the slope is switched to K1 or K2 and transitioned according to a continuous curve, where the motor torque change slope K is the change in the motor's required torque per unit time;

[0096] The torque iterative calculation unit uses a multi-core MCU (main frequency ≥ 200MHz) to iteratively calculate the current motor required torque T according to the following formula req_t : , Among them, T req_t-1 is the motor torque required at the last moment. It should be noted that the motor target torque T tar Far exceeds the current value, and approaches rapidly at the maximum slope K1; at the motor target torque T tar It is much lower than the current value and decreases rapidly according to the slope of K2; when the current value is close to the motor target torque T tar When rotating, keep the torque stable to avoid overshoot.

[0097] Furthermore, the zero-crossing control unit includes a gear clearance compensation firmware, which eliminates the axial clearance through the spring preload, maintains the tooth surface contact when the torque passes through zero, and can suppress the reverse impact when the torque passes through zero; it also includes a slope transition curve generator, which can dynamically adjust the slope change rate of the curve according to the torque deviation, and is used to adjust the slope of the curve according to the torque deviation. Figure 2 Generates continuously varying K1 / K2.

[0098] It should be noted that the information interaction, execution process, etc. between the above-mentioned units are based on the same concept as the method embodiment of the present application, and are a system corresponding to the above-mentioned electric vehicle torque slope adaptive control method. All implementation methods in the above-mentioned method embodiment are applicable to the embodiment of the system. Its specific functions and the technical effects brought about can be found in the method embodiment part, which will not be repeated here.

[0099] The present invention also provides an embodiment of an electric vehicle equipped with the above-mentioned electric vehicle torque slope adaptive control system, which can achieve significant improvements in transmission impact force, energy recovery rate and reducer life compared to traditional models.

[0100] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many variations and modifications are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and modifications. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A method for adaptively controlling torque slope of an electric vehicle, characterized in that: The following steps are involved: Step 1: Real-time acquisition of driving style recognition signal and accelerator pedal opening change d APP and motor target torque T tar ; Step 2: Match the regenerative braking torque change slope according to the driving style; Step 3: When the motor torque T req When entering the zero-crossing interval, the slope is switched to K1 or K2 and transitioned according to a continuous curve, where the motor torque change slope K is the change in the motor's required torque per unit time; Step 4: Iteratively calculate the current motor required torque T according to the following formula req_t : , where T req_t-1 The torque required by the motor at the previous moment.

2. The electric vehicle torque slope adaptive control method according to claim 1, characterized in that: In step 1, the driving style classification criteria are: Aggressive: historical accelerator pedal change rate (APR) average ≤ −30 Nm / s; Standard type: −30 Nm / s < APR mean ≤ −10 Nm / s; Conservative: APR average >−10Nm / s.

3. The electric vehicle torque slope adaptive control method according to claim 1, characterized in that: In step 2, the motor torque change slope K is fixedly set to: The rising slope K1 = 600Nm / s, and the falling slope K2 = -600Nm / s, which has nothing to do with driving style.

4. The electric vehicle torque slope adaptive control method according to claim 1, characterized in that: In step 2, the regenerative braking torque change slope is matched according to the driving style, including: Call the preset regenerative braking torque change slope according to driving style: Aggressive type: rising slope K1 = 200 Nm / s, falling slope K2 = −200 Nm / s; Standard type: rising slope K1 = 160 Nm / s, falling slope K2 = −160 Nm / s; Conservative type: rising slope K1 = 120 Nm / s, falling slope K2 = −120 Nm / s.

5. The electric vehicle torque slope adaptive control method according to claim 1, characterized in that: In step 2, the regenerative braking torque change slope is matched according to the driving style, further comprising: Limit the acceleration rate j during braking to 3 m / s 3 The acceleration change rate j of the driving process is limited to 10 m / s 3 Inside; According to the relationship between the motor torque change slope K and the acceleration change rate j: ， The reverse thrust motor torque change slope K is: ,in is the wheel radius, is the transmission efficiency, For vehicle weight, is the reduction ratio.

6. The electric vehicle torque slope adaptive control method according to claim 5, characterized in that: During the braking process, the motor torque change slope K is also calibrated according to the following rules: For aggressive driving styles, the motor torque change slope is calibrated based on the upper and lower limits of the acceleration change rate j during braking; For standard driving style, the motor torque change slope is calibrated to 80% of the aggressive driving style; For a conservative driving style, the motor torque change slope is calibrated to 60% of that for an aggressive driving style.

7. The electric vehicle torque slope adaptive control method according to claim 1, characterized in that: In step 3, the zero-crossing interval is set to [−35 Nm, 35 Nm].

8. The electric vehicle torque slope adaptive control method according to claim 7, characterized in that: In step 3, when the motor torque T req When entering the zero-crossing interval, the slope is switched to K1 or K2, specifically including: When the motor torque changes from positive to negative, at T req =0, K1=50Nm / s is used for transition; When the motor torque changes from negative to positive, at T req =0, K2=-50Nm / s is used for transition.

9. An electric vehicle torque slope adaptive control system, characterized in that: include: Data acquisition unit, used to obtain driving style recognition signal and accelerator pedal opening change in real time APP and motor target torque T tar ; A slope matching unit for matching the slope of regenerative braking torque changes according to driving style; Zero-crossing control unit, used when the motor torque T req When entering the zero-crossing interval, the slope is switched to K1 or K2 and transitioned according to a continuous curve, where the motor torque change slope K is the change in the motor's required torque per unit time; The torque iteration calculation unit is used to iteratively calculate the current motor required torque T according to the following formula req_t : , where T req_t-1 The torque required by the motor at the previous moment.

10. An electric vehicle, characterized in that: The electric vehicle torque slope adaptive control system according to claim 9 is mounted.

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