Energy recovery intensity real-time regulation and control method based on fuzzy control

Abstract

The invention discloses an energy recovery intensity real-time regulation and control method based on fuzzy control, and the main design concept of the method is as follows: deciding to use a basic energy recovery torque or solving a corrected energy recovery torque through a fuzzy control algorithm according to the identified gradient and the distance between vehicles in front of the vehicle; the vehicle control unit appoints the determined energy recovery torque as the requested energy recovery torque and sends the requested energy recovery torque to the motor, the motor completes the response of the requested energy recovery torque, the energy recovery torque is finely regulated and controlled according to the gradient and the distance between the vehicle ahead, the cruising ability of the vehicle can be effectively improved, and the driving experience is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy vehicles, and in particular to a real-time control method for energy recovery intensity based on fuzzy control. Background Art

[0002] As traditional fuel vehicles gradually transform towards electrification and intelligence, the market share and ownership of new energy vehicles are also increasing year by year. With the development of automobile electrification and intelligence, the energy recovery function of electric vehicles is also gradually moving towards ensuring drivability while maximizing the use of energy recovery power to increase the driving range of electric vehicles. The energy recovery of electric vehicles not only affects the user's driving comfort, but also involves the energy consumption of the entire vehicle. That is, how to achieve better recovery power through energy recovery has become a major challenge for the industry.

[0003] At present, the coasting energy recovery usually adopts calibration means, based on the two parameters of the motor speed and the accelerator pedal opening of the whole vehicle, the MAP table is queried through these two determined parameters, and the motor torque value obtained by the query is used to provide the motor with a recovery torque instruction. However, in this way, whether on a flat road, uphill or downhill, the motor recovery torque obtained by a fixed speed and accelerator pedal opening is a fixed value. For example, it is impossible to reasonably use downhill conditions and other working conditions for energy recovery to improve the energy recovery rate.

[0004] After further analysis of existing technologies, most solutions focus on adjusting the energy recovery torque based on vehicle status information (such as vehicle weight, speed, acceleration, etc.), and do not specifically control the energy recovery torque based on slope and distance to the vehicle ahead. Although such solutions can improve energy recovery efficiency to a certain extent, they cannot achieve the best effect in certain specific scenarios. Summary of the invention

[0005] In view of the above, the present invention aims to provide a real-time control method for energy recovery intensity based on fuzzy control to solve the above-mentioned technical problems.

[0006] The technical solution adopted by the present invention is as follows:

[0007] The present invention provides a real-time control method for energy recovery intensity based on fuzzy control, which includes:

[0008] Real-time detection of road slope and distance to the vehicle ahead when the vehicle is performing energy recovery;

[0009] When it is determined that the road has no slope and the distance to the vehicle ahead is greater than the preset safety distance, energy recovery is performed according to the basic energy recovery torque;

[0010] If it is detected that the road slope exceeds the preset slope threshold or the distance to the vehicle in front is less than or equal to the preset safety distance, the basic energy recovery torque is corrected using the fuzzy control algorithm;

[0011] The corrected target recovery torque is sent to the motor and a response is requested to perform energy recovery.

[0012] In at least one possible implementation, the correcting the basic energy recovery torque by using a fuzzy control algorithm includes:

[0013] At least the detected slope and the precise value of the distance to the preceding vehicle are fuzzified, including: respectively setting the basic domain, fuzzy set, and fuzzy subset domain of the slope and the distance;

[0014] The basic domain [a, b] is transformed into the fuzzy subset domain [-n, n] according to the following formula:

[0015] Among them, x is the precise value of the slope or spacing, and y is the fuzzy value of the slope or spacing.

[0016] In at least one possible implementation manner, performing energy recovery according to the basic energy recovery torque includes:

[0017] Calling a basic energy recovery torque mapping table that matches the current working conditions;

[0018] The basic energy recovery torque obtained by looking up the table is sent to the motor as a torque request instruction and requests the motor to respond to perform energy recovery.

[0019] In at least one possible implementation, calling a basic energy recovery torque mapping table matching the current operating condition includes:

[0020] Obtain the energy recovery intensity level corresponding to the vehicle model and preset;

[0021] According to the energy recovery intensity level, a pre-calibrated basic energy recovery torque mapping table corresponding to the current intensity level is called.

[0022] In at least one possible implementation, the basic energy recovery torque mapping table is used to characterize the mapping relationship between the motor speed and the accelerator pedal opening under a given energy recovery intensity.

[0023] In at least one possible implementation, the control method further includes: when the vehicle is performing energy recovery, real-time acquisition of the current vehicle speed, and determination of corresponding safety distance data according to the current vehicle speed.

[0024] In at least one possible implementation, during the process of energy recovery by the motor, if the vehicle cannot reach the recovery power corresponding to the target recovery torque due to battery characteristics, a reminder message for controlling the safe distance of the vehicle is output to the user.

[0025] Compared with the prior art, the main design concept of the present invention is that, based on the identified slope size and the distance to the vehicle ahead, a decision is made to use the basic energy recovery torque or to calculate the corrected energy recovery torque through a fuzzy control algorithm. The vehicle controller designates the determined energy recovery torque as the requested energy recovery torque and sends it to the motor, which completes the response to the requested energy recovery torque. The present invention finely controls the energy recovery torque based on the slope and the distance to the vehicle ahead, which can effectively improve the vehicle's endurance and significantly improve the driving experience.

[0026] Furthermore, it is preferred to set a corresponding soft switch in the in-vehicle infotainment system IVI, such as "intelligent energy recovery", so that the user can choose whether to turn on the above-mentioned energy recovery fuzzy control. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described below with reference to the accompanying drawings, in which:

[0028] Figure 1 A schematic diagram of a real-time regulation method for energy recovery intensity based on fuzzy control provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0029] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be interpreted as limiting the present invention.

[0030] The present invention proposes an embodiment of a real-time control method for energy recovery intensity based on fuzzy control. Specifically, Figure 1 shown, including:

[0031] Step S1, real-time detection of the road slope and the distance to the preceding vehicle when the vehicle is performing energy recovery;

[0032] Step S2: when it is determined that the road has no slope (no slope can be defined according to a predetermined slope threshold) and the distance to the vehicle in front is greater than a preset safety distance, energy recovery is performed according to the basic energy recovery torque; it can be added here that the safety distance is related to the current vehicle speed, so in actual operation, it can also include: when the vehicle is performing energy recovery, the current vehicle speed is collected in real time, and the corresponding safety distance data is determined according to the current vehicle speed.

[0033] When there is no slope and the distance to the vehicle in front is greater than the safe distance, it is only necessary to call the basic energy recovery torque MAP that matches the current working conditions, and send the basic energy recovery torque obtained from the table as a requested torque command to the power control unit PCU, requesting the PCU to respond to the torque command.

[0034] Specifically, the vehicle controller VCU receives the energy recovery intensity sent by the IVI controller through the CAN bus (generally, three energy recovery intensity levels such as strong, standard, and weak, or two energy recovery intensity levels of standard and strong can be set according to different vehicle models). Then, the VCU calls the pre-calibrated energy recovery torque mapping table (the aforementioned MAP) corresponding to the current intensity level according to the energy recovery intensity sent by the IVI controller.

[0035] Among them, the energy recovery torque MAP of different intensity levels can represent the mapping relationship between the motor speed and the accelerator pedal opening at the current given intensity.

[0036] Step S3: If it is detected that the road slope exceeds a preset slope threshold or the distance to the preceding vehicle is less than or equal to a preset safety distance, the basic energy recovery torque is corrected using a fuzzy control algorithm;

[0037] The present invention realizes two parameters for adjusting the energy recovery intensity. The first one is based on the identified road slope and adjusts the energy recovery intensity through a fuzzy control algorithm; the second one is based on the identified distance to the vehicle in front and adjusts the energy recovery intensity through a fuzzy control algorithm.

[0038] Therefore, it should be pointed out that the conditions for using fuzzy control algorithm for energy recovery regulation only need to meet one of the following two conditions:

[0039] (1) If the slope exceeds the set threshold, that is, if the uphill slope exceeds the set threshold (such as 3%), or if the downhill slope exceeds the set threshold (such as -3%), the energy recovery torque is corrected based on the basic energy recovery intensity (torque) through the fuzzy control algorithm;

[0040] (2) If the distance to the vehicle ahead is within the first safety range set at the current vehicle speed, the energy recovery torque is corrected based on the basic energy recovery torque through the fuzzy control algorithm and the distance to the vehicle ahead. Of course, if the distance to the vehicle ahead is within the second safety range set at the current vehicle speed (the second safety range is smaller than the first safety range), the instrument will be triggered to give a prompt, such as a prompt that the distance to the vehicle ahead is too close and please control the safety distance. At this time, the user needs to step on the brake pedal to ensure the safety distance.

[0041] Regarding the method of correcting the basic energy recovery torque based on the fuzzy algorithm, an example is given below: First, the two signal inputs of the slope size and the distance to the vehicle in front are fuzzified in the fuzzy control algorithm. For example, on the one hand, the basic domain of the slope size can be divided into [-30%, 30%], and the fuzzy set is {NS, NG, O, PG, PS}, where NS represents negative steepness, NG represents negative slowness, O represents zero, PG represents positive slowness, and PS represents positive steepness. The fuzzy subset domain is {-4, -3, -2, -1, 0, 1, 2, 3, 4}; on the other hand, the basic domain of the distance to the vehicle in front can be divided into [ 20, 150], let the fuzzy set be {VC, C, M, F, VF}, where VC means very close, C means close, M means medium, F means far, VF means very far, and the fuzzy subset domain is {-4, -3, -2, -1, 0, 1, 2, 3, 4}; of course, in addition to the above input, the basic domain of energy recovery intensity (torque) can also be set to [5, 100] according to the energy recovery intensity of different models, and let the fuzzy set be {VS, S, O, B, VB}, where VS means very small, S means small, O means zero, B means large, VB means very large, and the fuzzy subset domain is {-3, -2, -1, 0, 1, 2, 3}. Here is an example of fuzzy rules, as shown below, and the actual fuzzy rules can be created based on experience and actual calibration.

[0042] Table 1 Energy recovery intensity adjustable fuzzy rules

[0043]

[0044] It can be seen that the conversion relationship from the basic domain [a, b] to the fuzzy subset domain [-n, n] is:

[0045] Among them, x is the slope signal or the precise value of the distance to the front vehicle, and y is the slope signal or the fuzzy value of the distance to the front vehicle.

[0046] Step S4: Send the corrected target recovery torque to the motor and request a response to perform energy recovery.

[0047] In the above-mentioned fuzzy control algorithm, the corrected energy recovery intensity (torque) is obtained through the processes of fuzzy relationship, fuzzy decision-making and defuzzification. This corrected energy recovery torque is the target energy recovery torque to be requested, so the target request is sent to the motor, requesting the motor to respond and perform energy recovery.

[0048] It can also be pointed out here that when the vehicle has a related fault that prohibits energy recovery, the user can be notified to repair the vehicle to ensure driving safety; when the vehicle cannot reach the recovery power corresponding to the target recovery torque due to battery characteristics, the instrument can remind the user to pay attention to controlling the safe distance.

[0049] Therefore, the basic energy recovery torque is determined through the above steps, or the corrected energy recovery torque is obtained through the fuzzy control algorithm. The vehicle controller designates the determined energy recovery torque as the requested energy recovery torque and sends it to the motor. The motor completes the response to the requested energy recovery torque and completes the energy recovery function. In practical applications, the following effects can be achieved:

[0050] ① The adjustable energy recovery method can ensure that the energy recovery intensity is increased on downhill roads to avoid overspeeding; the energy recovery intensity is reduced on uphill roads, and the vehicle body inertia is used to continue moving forward to improve endurance; and there is no need to adjust the energy recovery intensity on flat roads;

[0051] ② The energy recovery adjustable method can avoid adjusting the energy recovery intensity when the distance to the vehicle ahead is beyond the safe distance; if the recognized distance is within the safe distance, the energy recovery intensity is increased, thereby realizing a flexible and dynamic energy recovery mechanism.

[0052] To sum up, the main design concept of the present invention is to decide whether to use the basic energy recovery torque or to calculate the corrected energy recovery torque through the fuzzy control algorithm according to the identified slope size and the distance to the vehicle ahead. The vehicle controller designates the determined energy recovery torque as the requested energy recovery torque and sends it to the motor, and the motor completes the response to the requested energy recovery torque. The present invention finely controls the energy recovery torque according to the slope and the distance to the vehicle ahead, which can effectively improve the vehicle's endurance and significantly improve the driving experience.

[0053] If the expressions expressing orientation are mentioned in the embodiments of the present invention, they are relative concepts based on the embodiments. In addition, "at least one" means one or more, and "plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Among them, A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can be represented by: a, b, c, a and b, a and c, b and c, or a and b and c, wherein a, b, c can be single or multiple.

[0054] The above describes in detail the structure, features and effects of the present invention based on the embodiments shown in the drawings, but the above is only a preferred embodiment of the present invention. It should be noted that the technical features involved in the above embodiments and their preferred methods can be reasonably combined and matched into a variety of equivalent schemes by those skilled in the art without departing from or changing the design ideas and technical effects of the present invention; therefore, the present invention is not limited to the scope of implementation shown in the drawings, and all changes made in accordance with the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which still do not exceed the spirit covered by the specification and drawings, should be within the protection scope of the present invention.

Claims

1. A real-time control method for energy recovery intensity based on fuzzy control, characterized in that: include: Real-time detection of road slope and distance to the vehicle ahead when the vehicle is performing energy recovery; When it is determined that the road has no slope and the distance to the vehicle ahead is greater than the preset safety distance, energy recovery is performed according to the basic energy recovery torque; If it is detected that the road slope exceeds the preset slope threshold or the distance to the vehicle ahead is less than or equal to the preset safety distance, the basic energy recovery torque is corrected using the fuzzy control algorithm; The corrected target recovery torque is sent to the motor and a response is requested to perform energy recovery.

2. The real-time control method of energy recovery intensity based on fuzzy control according to claim 1 is characterized in that: The method of correcting the basic energy recovery torque by using the fuzzy control algorithm includes: At least the detected slope and the precise value of the distance to the preceding vehicle are fuzzified, including: respectively setting the basic domain, fuzzy set, and fuzzy subset domain of the slope and the distance; The basic domain [a, b] is transformed into the fuzzy subset domain [-n, n] according to the following formula: Among them, x is the precise value of the slope or spacing, and y is the fuzzy value of the slope or spacing.

3. The real-time control method of energy recovery intensity based on fuzzy control according to claim 1 is characterized in that: The performing of energy recovery according to the basic energy recovery torque comprises: Calling a basic energy recovery torque mapping table that matches the current working conditions; The basic energy recovery torque obtained by looking up the table is sent to the motor as a torque request instruction and requests the motor to respond to perform energy recovery.

4. The real-time control method of energy recovery intensity based on fuzzy control according to claim 3 is characterized in that: The calling of the basic energy recovery torque mapping table matching the current working condition includes: Obtain the energy recovery intensity level corresponding to the vehicle model and preset; According to the energy recovery intensity level, a pre-calibrated basic energy recovery torque mapping table corresponding to the current intensity level is called.

5. The real-time control method of energy recovery intensity based on fuzzy control according to claim 3 is characterized in that: The basic energy recovery torque mapping table is used to characterize the mapping relationship between the motor speed and the accelerator pedal opening under a given energy recovery intensity.

6. The real-time control method of energy recovery intensity based on fuzzy control according to claim 1 is characterized in that: The control method further includes: when the vehicle is performing energy recovery, real-time acquisition of the current vehicle speed, and determining corresponding safety distance data according to the current vehicle speed.

7. The real-time control method for energy recovery intensity based on fuzzy control according to any one of claims 1 to 6, characterized in that: During the process of energy recovery by the motor, if the vehicle cannot reach the recovery power corresponding to the target recovery torque due to battery characteristics, a reminder message for controlling the safe distance of the vehicle will be output to the user.

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