Braking Energy Recovery Control Method Based on Riding Comfort

Abstract

The present invention relates to the technical field of automotive control methods, and specifically refers to a braking energy recovery control method based on ride comfort. The rated torque range is divided into a driving torque reduction range, a torque zero-crossing range, and a recovery torque increase range; the driving torque reduction range, the torque zero-crossing range, and the recovery torque increase range are respectively optimized and adjusted so that the driving torque reduction range and the torque zero-crossing range can be completed within a set time, and the formed torque-time curve is a smooth curve without inflection points. The braking energy recovery control method of the present invention performs targeted control on each stage of the braking process, maximally recovers braking energy while enabling the entire braking process to proceed very smoothly, solves problems such as abrupt braking and recovery delay, and has great promotional value.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle control methods, and specifically refers to a braking energy recovery control method based on ride comfort. Background Technique

[0002] At present, the coordinated energy recovery system based on wire control braking has gradually become the main development direction of new energy vehicles. However, due to reasons such as cost and technical complexity, its installation rate in the mid - low - end market (models with a post - subsidy price of 150,000 yuan or less) is not high. This market still mainly uses the superimposed braking recovery system. The superimposed braking energy recovery system, also known as the non - decoupled braking recovery system, means that the braking pedal force and the hydraulic braking force of the wheel cylinder are not decoupled. When the braking pedal is depressed in this system, the energy recovery braking force is superimposed on the mechanical braking force, resulting in the vehicle's braking force being higher than the driver's braking pedal demand, which has a negative impact on the braking feeling.

[0003] The current energy recovery is mainly achieved by the motor operating in a negative torque state during deceleration, that is, during deceleration, the motor acts as a "generator" to charge the power battery. Compared with the immediate response when the braking pedal is depressed to the braking effect of the brake caliper during mechanical braking, the energy recovery system mainly based on the motor has a certain delay in responding to the braking pedal signal, which is the so - called recovery intervention delay. The main reason is to protect the gears and splines of the motor - reducer - transmission shaft system.

[0004] During the process of the motor switching from the driving state to the recovery state, the torque changes from positive to negative, and the rotation direction of the motor remains unchanged (consistent with the driving direction), but the "driving" at the output end is switched to "dragging". During this process, each gear in the drive train needs to complete the process of switching the meshing direction. This switching process may cause obvious gear impact sounds and vehicle vibrations, which not only affect the ride and drive experience but also damage the service life of the motor and reducer gears. In severe cases, it may even cause gear fragmentation. Summary of the Invention

[0005] The purpose of the present invention is to solve the deficiencies of the above - mentioned background technique and provide a braking energy recovery control method based on ride comfort.

[0006] The technical solution of the present invention is as follows: A braking energy recovery control method based on ride comfort is carried out according to the following steps:

[0007] S1. Divide the rated torque range [-T min , T max into a driving torque reduction range [T a , T max , a torque zero - crossing range [-T a , Ta and the increased recovery torque range [-T min , -T a ;

[0008] S2. Obtain the first change rate R max corresponding to T downmax according to the motor bench test. According to the value range of the torque change rate R a corresponding to T a , select an appropriate R a to ensure that the time for the torque to decrease from T max to T a does not exceed the first set time;

[0009] Divide the driving torque reduction range [T a , T max into multiple optimized reduction ranges. Adjust the torque change rates of the initial value torque and the end value torque for each optimized reduction range except T a and T max . The torque change rates of other torque values within the range are obtained by linear interpolation according to the initial value torque change rate and the end value torque change rate. Perform simulation calculations on the obtained results to determine whether they meet the set requirements. If not, adjust the optimized reduction range until the set requirements are met, and construct a MAP graph with torque as the abscissa and torque change rate as the ordinate;

[0010] The set requirements of this application refer to the time requirement for completing the driving torque reduction range [T a , T max and that the constructed torque and time curve is smooth without inflection points;

[0011] S3. Select several torque values within the torque zero-crossing range [-T a , T a to divide the torque zero-crossing range [-T a , T a into multiple optimized zero-crossing ranges. Set the torque change rates of the selected torque values within the set range. The torque change rates of other torques within the optimized zero-crossing range are obtained by linear interpolation to ensure that the time for the torque zero-crossing range [-T a , T a does not exceed the second set time;

[0012] S4. Select the second change rate R min corresponding to -T upnmax within the set range, and maintain the torque change rate within the increased recovery torque range [-T min , -T a as the second change rate R upnmax, ensure that the torque time curve part corresponding to the increased recovery torque range [-T min , -T a and the torque time curve part corresponding to the torque zero-crossing range [-T a , T a and the connection point of the torque time curve part corresponding to the driving torque reduction range [T a , T max are smooth without inflection points;

[0013] where T max is the maximum rated torque of the motor, -T min is the maximum recovery torque of the motor, T min is less than T max .

[0014] According to a braking energy recovery control method based on ride comfort provided by the present application, in the step S2, calculate the initial value torque change rate of the torque within the driving torque reduction range [T a , T max except for T a and T max according to the following formula:

[0015]

[0016] where: R n ——The initial value torque change rate of the torque within the driving torque reduction range [T a , T max except for T a and T max ;

[0017] T n ——The torque within the driving torque reduction range [T a , T max except for T a and T max ;

[0018] R downmax ——The torque change rate corresponding to T max ;

[0019] R a ——The torque change rate corresponding to T a ;

[0020] Then, calculate whether the completion time of the driving torque reduction range [T a , T max exceeds the first set time. If it exceeds the first set time, reselect R a within the value range of the torque change rate R a, until the driving torque reduction interval [T a , T max is completed within no more than the first set time.

[0021] According to a braking energy recovery control method based on ride comfort provided by the present application, in the step S2, the method for adjusting the torque change rate of the initial torque value and the end torque value of each optimization reduction interval except T a and T max includes: adjusting the torque change rate of the initial torque value and the end torque value of each optimization reduction interval except T a and T max according to the following formula:

[0022]

[0023] Where: R N ——The torque change rate of the initial torque value and the end torque value of each optimization reduction interval except T a and T max ;

[0024] T N ——The initial torque value and the end torque value of each optimization reduction interval except T a and T max ;

[0025] R downmax ——The torque change rate corresponding to T max ;

[0026] R a ——The torque change rate corresponding to T a ;

[0027] S——Coefficient, the value range is 0.02 to 0.03.

[0028] According to a braking energy recovery control method based on ride comfort provided by the present application, in the step S2, the method for adjusting the optimization reduction interval includes: first dividing the driving torque reduction interval [T a , T max into multiple optimization reduction intervals according to a limit value of 50 Nm, and then adjusting the end value of each optimization reduction interval except T max by -10 Nm to 10 Nm to obtain the optimized adjustment of the optimization reduction interval.

[0029] According to a braking energy recovery control method based on ride comfort provided by the present application, the first set time is 0.3 s; the T a is 10 Nm, and the torque change rate R corresponding to the T a ​a The value range of a ≤ -100 Nm / s.

[0030] According to a braking energy recovery control method based on riding comfort provided by the present application, in the step S3, the method for selecting several torque values within the torque zero-crossing interval [-T a , T a includes: selecting 0, selecting a certain torque T a between 0 and T b , selecting the torque -T a between -T b and 0;

[0031] Or selecting 0, selecting a certain torque T a between 0 and T b , selecting a certain torque T b between 0 and T c , selecting the torque -T a between -T b and 0, selecting the torque -T a between -T b and -T c .

[0032] According to a braking energy recovery control method based on riding comfort provided by the present application, the T a is 10 Nm, and -3 Nm, 0 Nm and 3 Nm in [-T a , T a are selected;

[0033] Or -3 Nm, -1.5 Nm, 0 Nm, 1.5 Nm and 3 Nm in [-T a , T a are selected.

[0034] According to a braking energy recovery control method based on riding comfort provided by the present application, in the step S3, the method for setting the torque change rate of the selected torque value within a set range includes: the torque change rates corresponding to -3 Nm and 3 Nm do not exceed -100 Nm / s, and the torque change rate corresponding to 0 Nm does not exceed -30 Nm / s.

[0035] According to a braking energy recovery control method based on riding comfort provided by the present application, the second set time is 0.5 s.

[0036] According to a braking energy recovery control method based on riding comfort provided by the present application, in the step S4, the method for setting the torque change rate of the selected torque value within a set range includes: selecting the torque change rate of the torque value between -100 Nm / s and -200 Nm / s.

[0037] The advantages of the present invention are as follows: 1. The braking energy recovery process of the present invention is divided into three segments: the torque reduction stage, the torque zero-crossing stage, and the torque increase stage. Different control measures are adopted for each stage. For the torque reduction segment, the present application divides the torque optimization reduction interval, adjusts the torque value of each partition, and makes the MAP graph of the torque in the torque optimization reduction interval with respect to time a smooth curve without inflection points. The torque reduction process is completed within the set time and the torque change is smoother, avoiding problems such as jitter and abnormal noise during this process;

[0038] In the torque zero-crossing interval, values are selected and set for the torque zero-crossing interval. The torque zero-crossing interval can be completed quickly, the torque zero-crossing interval is greatly shortened, and the recovered torque can quickly reach the maximum value, ensuring the maximum recovery of braking energy;

[0039] In the torque increase interval, by limiting the torque change rate, the braking energy is recovered to the greatest extent, and it is smoothly connected with the torque optimization reduction interval, avoiding jitter. After the torque is reversed, the change is more gentle and linear, and the overall driving experience is greatly improved;

[0040] 2. The present invention adjusts the change rates of the initial torque and the end torque of each optimization reduction interval by setting formulas, and calculates the torque change rates of other torques in each optimization reduction interval using linear interpolation. The entire adjustment and setting method is extremely simple, and the constructed formula makes the curve of the entire MAP graph smoother and without inflection points. Reflected in the actual driving, a smoother and jitter-free driving experience can be obtained;

[0041] 3. The present invention first sets a preliminary optimization reduction interval, and then performs optimization adjustment on the basis of the preliminary optimization reduction interval. It can be optimized and adjusted according to the actual vehicle operation. The adjustment range is reduced and the adjustment efficiency is improved, which is convenient for design optimization;

[0042] 4. The present invention sets the time limit for completing the torque optimization reduction interval to 0.3 s, which is convenient for the torque optimization reduction interval stage to quickly reach the maximum recovered torque and is convenient for the quick recovery of braking energy. The setting of the first set time is convenient for adjusting the starting torque value of the torque optimization reduction interval;

[0043] 5. The present invention sets the value range of the torque change rate of the starting torque of the torque optimization reduction interval to R a ≤ -100 Nm / s. Setting this value range can cooperate with the first set time to quickly obtain the torque change rate corresponding to 10 Nm, and quickly obtain the maximum recovered torque while ensuring smooth driving in the torque optimization reduction interval;

[0044] 6. The setting of the torque zero-crossing interval in the present invention is to directly select several torque values within this interval for setting. The selected torque values can be determined according to empirical values. Such a selection method can quickly obtain the torque setting situation in the torque zero-crossing interval, and the torque adjustment scheme in the torque zero-crossing interval can be determined according to empirical values, facilitating the smooth and rapid transition of the torque zero-crossing interval;

[0045] 7. The torque values selected for the torque zero-crossing interval in the present invention are the torque values close to the 0 point. By determining the torque change rates of these torque values, the adjustment scheme for the torque change in the torque zero-crossing interval can be quickly obtained. The setting is simple and efficient, and the torque change in the torque zero-crossing interval is smooth;

[0046] 8. The present invention sets a range for the torque change rates corresponding to -3 Nm and 3 Nm selected for the torque zero-crossing interval. This set range, combined with the second setting time, can quickly obtain the adjustment scheme for the torque zero-crossing interval, and the entire design optimization method is simple;

[0047] 9. The second setting time in the present invention is 0.5 s. Setting this time in combination with the torque change rate of the torque values selected for the torque zero-crossing interval can quickly obtain the torque adjustment scheme for the torque zero-crossing interval, shorten the amplitude of the torque zero-crossing interval, and improve the smoothness of the torque zero-crossing interval;

[0048] 10. The present invention sets a selection range for the torque change rate in the torque increasing interval, ensuring the smooth transition of the torque change rate between the torque increasing interval and the torque zero-crossing interval, avoiding inflection points or jumps at the connection of the two intervals, improving the smoothness of the torque zero-crossing and torque increasing processes, and avoiding problems such as jitter that affect the driving experience.

[0049] The braking energy recovery control method of the present invention performs targeted control on each stage during braking. While maximizing the recovery of braking energy, the entire braking process can proceed very smoothly, solving problems such as abrupt braking and recovery delay, and having great promotional value. Brief Description of the Drawings

[0050] Figure 1 : Schematic diagram of the existing braking energy recovery control method and the braking energy recovery control method of the present application (the upper curve is the torque-time curve corresponding to the existing braking energy recovery control method, and the lower curve is the torque-time curve corresponding to the braking energy recovery control method of the present application). Detailed Description of the Embodiment

[0051] The following details the embodiments of the present invention, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0052] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0053] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0054] The present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0055] This application relates to a method for controlling the recovery of automotive braking energy. The braking energy recovery control method of this application divides the automotive braking process into three intervals: the driving torque reduction interval, the torque zero-crossing interval, and the recovery torque increase interval. Different methods are used for the torque control in each interval. By performing different controls on each interval, the change of torque during the braking process of the vehicle is made smoother, eliminating the adverse feelings of impact, jitter, and delayed recovery intervention caused by the commutation of the motor torque, and eliminating the adverse feeling of sudden change in braking force after the driver steps on the brake pedal under the superposition type braking energy recovery system.

[0056] The specific control method is carried out according to the following steps:

[0057] S1. Divide the rated torque interval [-T min , T max into a driving torque reduction interval [T a , T max , a torque zero-crossing interval [-T a , T a , and a recovery torque increase interval [-T min , -T a ;

[0058] The driving torque reduction interval [T a , T max is the first interval of the braking process. When the vehicle brakes, the brake pedal is depressed, and the driving torque of the vehicle decreases from T maxStart to decrease; when it decreases to T a , it starts to enter the torque zero-crossing interval [-T a , T a . The driving torque will decrease to 0 during this process until it changes from driving to dragging, and the driving torque becomes negative; the recovery torque continues to increase. After exceeding -T a , it enters the recovery torque increasing interval [-T min , -T a ;

[0059] Normally, the rated torque interval of the motor is [-T max , T max . However, in the actual application process, the recovery torque of the motor cannot reach -T max . Therefore, -T min is introduced. -T min is the maximum recovery torque of the motor. When the motor reaches the maximum recovery torque -T min , the recovery torque of the motor no longer changes and remains at the maximum recovery torque -T min . For this reason, the recovery torque increasing interval in this case is set as [-T min , -T a ;

[0060] S2. According to the motor bench test, obtain the first change rate R max corresponding to T downmax . Select a suitable R a according to the value range of the torque change rate R a corresponding to T a to ensure that the time for the torque to decrease from T max to T a does not exceed the first set time;

[0061] Divide the driving torque reduction interval [T a , T max into multiple optimized reduction intervals. Adjust the torque change rates of the initial value torque and the end value torque for each optimized reduction interval except T a and T max . The torque change rates of other torque values within the interval are obtained by linear interpolation according to the initial value torque change rate and the end value torque change rate. Perform simulation calculation on the obtained results to judge whether they meet the set requirements. If not, adjust the optimized reduction intervals until they meet the set requirements, and construct a MAP graph with torque as the abscissa and torque change rate as the ordinate;

[0062] Before the motor leaves the factory, corresponding bench tests will be carried out. According to the situation of the bench tests, the first change rate R max corresponding to Tdownmax ; while T a The corresponding torque change rate R a is set, and T itself a is also selected. The torque change rate R a is determined according to the first set time. Determine T a The corresponding torque change rate R a is a preliminary determination, and its purpose is to meet the change time of the driving torque reduction interval [T a , T max , that is, to complete the process of reducing the driving torque within the set time requirement and meet the requirement of rapid braking. However, at this time, only the braking requirement is preliminarily met, and the requirement of eliminating jitter and impact while performing rapid braking is not met. That is, the change in torque makes the vehicle not smooth during the braking process. Therefore, it is necessary to further optimize the reduction of the driving torque;

[0063] Specifically, in this application, the driving torque reduction interval [T a , T max is partitioned, and then the endpoints of each optimized reduction interval are re-optimized and adjusted to make the finally formed torque-time curve smoother. Corresponding to the braking process, it means that the torque control is smoother, and the problems of jitter and impact during the braking process can be eliminated. The optimization of the endpoints of the reduction interval is to optimize the setting method, and the values outside the endpoints of the optimized reduction interval are obtained by linear interpolation, that is, to ensure that the time of the optimized driving torque reduction interval [T a , T max still meets the above set time requirement;

[0064] S3. Select several torque values within the torque zero-crossing interval [-T a , T a to divide the torque zero-crossing interval [-T a , T a into multiple optimized zero-crossing intervals. Set the torque change rate of the selected torque values within the set range, and the torque change rates of other torques within the optimized zero-crossing intervals are obtained by linear interpolation, so as to ensure that the time of the torque zero-crossing interval [-T a , T a does not exceed the second set time;

[0065] The control of the torque zero-crossing interval [-T a , T a is achieved by precisely setting specific torques within the torque zero-crossing interval [-T a , T a . This precise setting is based on the torque zero-crossing interval [-T a , T aThe completion time, and T a is determined according to the corresponding torque change rate, and the purpose is that the torque zero-crossing interval [-T a , T a can be completed within the set time and can be properly connected with the driving torque reduction interval, avoiding the appearance of inflection points at the connection position (corresponding to vehicle braking, which is jitter or impact), that is, the torque-time curve formed by the driving torque reduction interval [T a , T max and the torque-time curve of the torque zero-crossing interval [-T a , T a are smoothly connected without inflection points at the connection position;

[0066] S4. Select the second change rate R min corresponding to -T upnmax within the set range, and maintain the torque change rate within the recovery torque increasing interval [-T min , -T a to be the second change rate R upnmax , ensuring that the connection between the torque-time curve part corresponding to the recovery torque increasing interval [-T min , -T a and the torque-time curve part corresponding to the torque zero-crossing interval [-T a , T a and the torque-time curve part corresponding to the driving torque reduction interval [T a , T max is smooth without inflection points;

[0067] When the recovery torque exceeds -T a , at this time, as the braking continues, the recovery torque gradually increases, and more and more energy is recovered by braking. At this time, it is necessary to consider recovering the braking energy to the greatest extent and quickly reaching the maximum recovery torque allowed by the vehicle. Then, on this basis, the smoothness of the entire recovery torque increasing process is determined. Since the recovery torque increasing interval is connected to the torque zero-crossing interval, the torque change rate for -T a needs to be set and adjusted specifically to avoid the appearance of non-smoothness or inflection points at the connection position between the two intervals, that is, the connection position between the torque-time curve formed by the recovery torque increasing interval [-T min , -T a and the torque-time curve of the torque zero-crossing interval [-T a , T a is smooth and without inflection points.

[0068] In some embodiments of the present application, this embodiment optimizes the above step S2. Specifically, in step S2, the driving torque reduction interval [T a, T max excluding T a and T max The initial value torque change rate of the torque other than:

[0069]

[0070] Where: R n —— The driving torque reduction interval [T a , T max excluding T a and T max The initial value torque change rate of the torque other than;

[0071] T n —— The driving torque reduction interval [T a , T max excluding T a and T max The torque other than;

[0072] R downmax —— The torque change rate corresponding to T max ;

[0073] R a —— The torque change rate corresponding to T a ;

[0074] Then, calculate whether the completion time of the driving torque reduction interval [T a , T max exceeds the first set time. If it exceeds the first set time, reselect R a within the value range of the torque change rate R a until the completion time of the driving torque reduction interval [T a , T max does not exceed the first set time. In fact, it is to continuously repeat the attempt within the set value range until the selected R a meets the set time requirement. The purpose of this step is to preliminarily determine the torque change rate R a of T a .

[0075] In the above step S2, the method for adjusting the torque change rate of the initial value torque and the end value torque of each optimized reduction interval other than T a and T max includes: In this embodiment, after determining the torque change rate R max corresponding to T downmax through the motor bench test, for the driving torque reduction interval [T a , T maxA preliminary partition has been carried out, and the graduation value of the preliminary partition is set according to the actual situation, such as 50 Nm. The driving torque reduction interval [T a , T max is divided into multiple independent optimized reduction intervals. At this time, the endpoint values of the preliminary optimized reduction intervals of the torque except T a and T max can be calculated by the following formula:

[0076]

[0077] Where: R N ——The torque change rate of the initial value torque and the end value torque of each optimized reduction interval except T a and T max ;

[0078] T N ——The initial value torque and the end value torque of each optimized reduction interval except T a and T max ;

[0079] R downmax ——The torque change rate corresponding to T max ;

[0080] R a ——The torque change rate corresponding to T a ;

[0081] S——Coefficient, the value range is 0.02 to 0.03.

[0082] In this embodiment, only the endpoint values of the optimized reduction intervals are calculated. The values of each optimized reduction interval except the endpoints are calculated by linear interpolation through the endpoints. On the MAP graph of torque and torque change rate, it is a multi-segment broken line structure, that is, each optimized reduction interval corresponds to a straight line, and the straight lines of multiple optimized reduction intervals are connected to form a multi-segment broken line. However, in the actual operation process, it is also necessary to observe the MAP graph of torque and time, that is, observe the relationship curve with torque as the X-axis and time as the Y-axis during the process of the driving torque reduction interval [T a , T max . It is necessary to ensure that this curve is smooth. In terms of driving experience, the smoother the curve, the better the driving experience. Once there is an inflection point on the curve, it will form jitter or impact in terms of experience.

[0083] According to the above formula and the calculation results, the above results can be verified by simulation to see if they meet the driving torque reduction interval [T a , T maxThe time requirement, and at the same time, it is also possible to observe that in the case of the above calculation results, whether the curve of torque and time is smooth during the process of the driving torque reduction interval [T a , T max . If the set time requirement is not met or the torque-time curve is not smooth, it is necessary to optimize and adjust the optimization reduction interval.

[0084] In some other embodiments of the present application, the method for optimizing and adjusting the optimization reduction interval in step S2 above includes: first dividing the driving torque reduction interval [T a , T max into multiple optimization reduction intervals according to a limit value of 50 Nm, and then adjusting the end value of each optimization reduction interval except T max by -10 Nm to 10 Nm to obtain the optimized optimization reduction interval after adjustment.

[0085] For example, if T a is set to 10 Nm, T max is set to 300 Nm, and the initial graduation value is 50 Nm, then [10, 300] can be divided into six preliminary optimization reduction intervals: [10, 60], [60, 110], [110, 160], [160, 210], [210, 260], and [260, 300]. Then, uniformly adjust 60, 110, 160, 210, and 260 by -10 Nm to 10 Nm to obtain the optimized optimization reduction interval after adjustment. Here, the optimization adjustment is to adjust each optimization reduction interval separately, and the adjustment range is -10 Nm to 10 Nm. That is to say, assuming that the end value of an optimization reduction interval is 70 Nm, the end value of the optimized optimization reduction interval after adjustment can be 71 Nm or 79 Nm.

[0086] Adjust the torque change rate corresponding to the torque at the end point value of the optimized optimization reduction interval according to the above formula to obtain the optimized end point torque change rate. According to the end point torque change rate, obtain the torque-torque change rate relationship diagram and the torque-time relationship curve of the driving torque reduction interval [T a , T max . Analyze the torque-time relationship curve of the driving torque reduction interval [T a , T max to determine whether there are inflection points or non-smooth places (mainly the connection positions between adjacent optimization reduction intervals). If so, re-adjust the end points of the optimization reduction interval by increasing or decreasing until a smooth torque-time relationship curve diagram of the driving torque reduction interval [T a , T max without inflection points is obtained.

[0087] The first set time of this embodiment is 0.3 s. As Figure 1 shown, the time taken to complete the driving torque reduction interval [T a , T max is 0.24 s, that is, the time taken to complete the driving torque reduction interval [T a , T max shall not exceed 0.3 s.

[0088] T a of this embodiment is set to 10 Nm, and the corresponding torque change rate R a has a value range of R a ≤ -100 Nm / s. a

[0089] In some other embodiments of the present application, in this embodiment, for the above step S3, the method of selecting several torque values within the torque zero-crossing interval [-T a , T a is optimized. Specifically, 0 can be selected, a certain torque T a between 0 and T b can be selected, the torque -T a between -T b and 0 can be selected; or 0 can be selected, a certain torque T a between 0 and T b can be selected, a certain torque T b between 0 and T c can be selected, the torque -T a between -T b and 0 can be selected, the torque -T a between -T b and -T c can be selected.

[0090] More specifically, T a is 10 Nm, and -3 Nm, 0 Nm, and 3 Nm in [-T a , T a are selected; or -3 Nm, -1.5 Nm, 0 Nm, 1.5 Nm, and 3 Nm in [-T a , T a are selected.

[0091] Among them, the torque change rates corresponding to -3 Nm and 3 Nm do not exceed -100 Nm / s, and the torque change rate corresponding to 0 Nm does not exceed -30 Nm / s.

[0092] The above adjustments are mainly made and set based on experience, that is, through a large number of actual vehicles for verification. When in the torque zero-crossing interval [-T a , T a, when -3 Nm, 3 Nm, and 0 Nm are set within the above range, the process can be completed smoothly, and the driver can't feel jitter or impact, providing good comfort for the driver in the torque zero-crossing interval [-T a , T a .

[0093] And the time taken for the torque zero-crossing interval [-T a , T a does not exceed a second set time, which is 0.5 s, that is, the time taken for the torque zero-crossing interval [-T a , T a does not exceed 0.5 s. As shown in Figure 1 , the time taken for the torque zero-crossing interval [-T a , T a is 0.3 s.

[0094] The above method can obtain the torque change rate corresponding to T a (obtained by analyzing the drive torque reduction interval [T a , T max ), as well as some specific torque change rates in the torque zero-crossing interval [-T a , T a , the torque change rates corresponding to -3 Nm, 0 Nm, and 3 Nm. Then, by setting the second set time, the value range corresponding to -T a can be obtained.

[0095] This adjustment can also be verified through in-vehicle operation. Conduct in-vehicle tests to observe whether there are any abnormalities such as motor jitter or reducer gear knocking sounds in the Tip IN / OUT working conditions at any vehicle speed in the range of 10 km / h to 30 km / h; if such abnormalities occur, it is necessary to collect data such as the actual torque and actual speed of the motor, clarify the torque interval corresponding to the occurrence of abnormalities such as jitter and knocking sounds, and modify the torque value corresponding to the torque selected for the torque zero-crossing interval [-T a , T a . This part of the modification is a fine adjustment, usually carried out within the range of -50 Nm to 50 Nm.

[0096] In a further embodiment of the present application, this embodiment optimizes the method for setting the torque change rate of the selected torque value within the set range in step S4 above. Specifically, the torque change rate of the torque value is selected between -100 Nm / s and -200 Nm / s. In the regenerative torque increasing interval [-T min , -T a , the torque change rate of the entire interval remains unchanged, that is, when entering the regenerative torque increasing interval [-T min, -T a can quickly reach the maximum recovery torque, maximizing the recovery of braking energy. In this embodiment, the maximum recovery torque is set, and a suitable recovery torque is selected according to the above range. At the same time, it is necessary to consider the connection problem between the increasing range of the recovery torque [-T min , -T a and the torque zero-crossing range [-T a , T a , that is, the torque change rate corresponding to -T in the increasing range of the recovery torque [-T min , -T a is equal to the torque change rate of -T in the torque zero-crossing range [-T a , T a , T a . There should be no inflection point at the connection of the torque-time curve corresponding to the torque zero-crossing range [-T a , T a , T a and the time curve corresponding to the increasing range of the recovery torque [-T min , -T a .

[0097] In practical applications, from a time perspective, the increasing range of the recovery torque [-T min , -T a can be divided into two stages. One is the stage of increasing the recovery torque. This stage starts from -T a and continuously increases according to the set torque change rate of -T a until it increases to the maximum recovery torque -T min ; the second stage is that after reaching the maximum recovery torque -T min , the torque change rate directly becomes 0, and continuous braking energy recovery is carried out according to the maximum recovery torque -T min .

[0098] In the analysis process of the torque zero-crossing range [-T a , T a , the torque change rate corresponding to -T a can obtain a value range based on the second set time, while in the analysis process of the increasing range of the recovery torque [-T min , -T a , the torque change rate corresponding to -T a has another value range. The intersection of the two value ranges is the value range that meets the set requirements. Select a suitable torque change rate corresponding to -T a within this value range.

[0099] The maximum recovery torque of this application, that is, -T min does not exceed -100 Nm.

[0100] The torque control method is obtained according to the above method, and a complete relationship curve of torque, torque change rate and time is constructed and then stored in the vehicle control system. When the braking demand occurs during the actual vehicle operation, the corresponding control adjustment can be made according to the above relationship curve.

[0101] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and what is described in the above embodiments and the specification is only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and all these changes and improvements fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. A braking energy recovery control method based on riding comfort, characterized in that: Proceed as follows: S1. Divide the rated torque range [-T min , T max into a driving torque reduction range [T a , T max , a torque zero-crossing range [-T a , T a , and a recovery torque increase range [-T min , -T a ; S2. Obtain the corresponding first change rate R of T according to the motor bench test max and select an appropriate R according to the value range of the torque change rate R downmax corresponding to T a to ensure that the time for the torque to decrease from T a to T a does not exceed the first set time; max a ​​ Divide the drive torque reduction interval [T a , T max into multiple optimized reduction intervals, adjust the torque change rates of the initial torque value and the end torque value for each optimized reduction interval except T a and T max . The torque change rates of other torque values within the interval are obtained by linear interpolation according to the initial torque change rate and the end torque change rate. Perform simulation calculations on the obtained results to determine whether they meet the set requirements. If not, adjust the optimized reduction interval until the set requirements are met, and construct a MAP graph with torque as the abscissa and torque change rate as the ordinate; S3. Select several torque values within the torque zero-crossing interval [-T a , T a to divide the torque zero-crossing interval [-T a , T a into multiple optimized zero-crossing intervals, set the torque change rate of the selected torque values within a set range, and obtain the torque change rates of other torques within the optimized zero-crossing intervals by linear interpolation, so as to ensure that the time of the torque zero-crossing interval [-T a , T a does not exceed the second set time; S4. Select a -T within the set range min The corresponding second change rate R upnmax , maintain the recovery torque increasing range [-T min , -T a , and make the torque change rate within the range be the second change rate R upnmax , ensure that the torque-time curve part corresponding to the recovery torque increasing range [-T min , -T a is smoothly connected without inflection points to the torque-time curve part corresponding to the torque zero-crossing range [-T a , T a and the torque-time curve part corresponding to the driving torque decreasing range [T a , T max .

2. The braking energy recovery control method based on riding comfort as described in claim 1, wherein: In the step S2, the initial value torque change rate of the torque within the driving torque reduction interval [T a , T max , excluding T a and T max is calculated according to the following formula: Wherein: R n —— The initial value torque change rate of the torque other than T a , T max within the driving torque reduction interval a and T max ; T n ——Driving torque reduction range [T a , T max ]Inside the T a and T max Other than torque; R downmax ——T max The corresponding torque change rate; R a ——T a The corresponding torque change rate; Then, calculate whether the completion time of the driving torque reduction interval [T a , T max exceeds the first set time. If it exceeds the first set time, reselect R a within the value range of the torque change rate R a , until the completion time of the driving torque reduction interval [T a , T max does not exceed the first set time.

3. The braking energy recovery control method based on riding comfort as claimed in claim 1, wherein: In the step S2, the method for adjusting the optimized reduction interval includes: first, dividing the driving torque reduction interval [T a , T max into multiple optimized reduction intervals according to a limit value of 50 Nm, and then adjusting the end value of each optimized reduction interval except T max by -10 Nm to 10 Nm to obtain the optimized reduction interval after optimized adjustment.

4. The braking energy recovery control method based on riding comfort as described in claim 1, characterized in that: The first set time is 0.3 s; the T a is 10 Nm, the T a corresponding torque change rate R a has a value range of R a ≤ -100 Nm / s.

5. A braking energy recovery control method based on riding comfort as claimed in claim 1, characterized in that: In the step S3, the method for selecting several torque values within the torque zero-crossing interval [-T a , T a includes: selecting 0, selecting a certain torque T a between 0 and T b , selecting -T a between -T b and 0; Or select 0, select 0 and a certain torque T between 0 and T a and a certain torque T between 0 and T b , select 0 and a certain torque T b and a certain torque T between 0 and T c , select -T a and the torque -T between -T and 0 b , select -T a and -T b and the torque -T between -T and -T c .

6. The braking energy recovery control method based on riding comfort as claimed in claim 5, wherein: The said T a is 10 Nm, and -3 Nm, 0 Nm, and 3 Nm in [-T a , T a are selected; Or select [-T a , T a among -3 Nm, -1.5 Nm, 0 Nm, 1.5 Nm and 3 Nm.

7. The braking energy recovery control method based on riding comfort as described in claim 6, characterized in that: In the step S3, the method for setting the torque change rate of the selected torque value within a set range includes: the torque change rates corresponding to -3 Nm and 3 Nm do not exceed -100 Nm / s, and the torque change rate corresponding to 0 Nm does not exceed -30 Nm / s.

8. The braking energy recovery control method based on riding comfort as described in claim 1, wherein: The second set time is 0.5 s.

9. A braking energy recovery control method based on riding comfort as claimed in claim 1, characterized in that: In the step S4, the method for setting the torque change rate of the selected torque value within a set range includes: selecting the torque change rate of the torque value between -100 Nm / s and -200 Nm / s.

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