A method and device for controlling coasting recovery torque based on working condition self-adaptation

Abstract

The application provides a kind of based on working condition adaptive coasting recovery torque control method and device.The method includes: real-time acquisition vehicle driving parameter, and according to the driving parameter determination whether to enter or keep coasting mode;In coasting mode, according to the vehicle mass and road slope, the recovery intensity level is calculated, and the target coasting recovery torque is calculated based on the recovery intensity level;The target coasting recovery torque is output to motor controller, and the motor is controlled by motor controller braking.The application simultaneously considers the influence of vehicle mass and road slope on coasting recovery torque control, and still can provide more comfortable coasting deceleration when downhill, compared with the existing uniform speed coasting downhill technology, improves the braking safety of vehicle in different operation scenarios.

Description

Technical Field

[0001] This invention belongs to the field of electric vehicle control technology, specifically relating to a coasting recovery torque control method and device based on adaptive operating conditions. Background Technology

[0002] Currently, due to energy conservation and emission reduction requirements and operational cost considerations, electric vehicles are being used more and more widely. Electric vehicles are accounting for an increasing proportion of buses, transport vehicles, and private cars; there are also new energy special-purpose vehicles used in mines, ports, and other areas, which are gradually replacing traditional special-purpose vehicles. However, the main pain points for new energy special-purpose vehicles are still the range issue, leading to a series of problems such as battery cost, weight, and charging time. To further improve energy utilization and range, during vehicle coasting, the motor enters a power generation mode, outputting negative torque for energy recovery. Under specific operating conditions, reasonable energy recovery torque control can increase the range by 20%, while further reducing the frequency of mechanical braking and extending the lifespan of mechanical braking components such as the air pump.

[0003] New energy special vehicles, considering factors such as the size and efficiency of the electric drive system, generally adopt a multi-gear design, with the current mainstream being a 4-speed AMT electric drive system. During gear shifting in the electric drive system, power interruption can occur. During coasting recovery, if downshifting is triggered, the vehicle may experience loss of deceleration, forward lurching, and jerking, resulting in a poor driving experience. Furthermore, downshifting reduces the efficiency of coasting recovery. Simultaneously, when special vehicles are in operation (tractor-trailers carrying cargo and empty, sanitation vehicles sweeping), variations in the work scenario and time, changes in vehicle weight, gradient, the gear used to enter coasting recovery, and the current energy management system's recoverable power all affect the control of coasting recovery torque. Ignoring these variations in operating conditions and vehicle parameters and performing energy recovery according to a fixed recovery MAP not only fails to effectively recover energy but also leads to a decrease in comfort.

[0004] Existing technologies typically provide drivers with a multi-level adjustable control switch, allowing them to manually adjust the regenerative braking torque intensity based on the current operating conditions. Generally, drivers are instructed to activate the strong regenerative braking mode when heavily loaded downhill, adjust the appropriate intensity based on the estimated forward distance at traffic lights on flat roads, and deactivate regenerative braking when going uphill. However, this setup places high demands on drivers, as drivers of special-purpose vehicles often have years of experience driving conventional vehicles. To maximize the utilization of the energy recovery system, drivers need to understand the unique characteristics of energy recovery in these new energy special-purpose vehicles. Therefore, in practical use, it has been found that drivers often only use the default regenerative braking setting or disable regenerative braking altogether, preventing the full realization of the energy recovery advantages of new energy special-purpose vehicles. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, this invention provides a coasting recovery torque control method and apparatus based on adaptive operating conditions.

[0006] To achieve the above objectives, the present invention adopts the following technical solution.

[0007] In a first aspect, the present invention provides a coasting regenerative torque control method based on operating condition adaptation, comprising the following steps executed in the vehicle controller:

[0008] The vehicle's driving parameters, including accelerator pedal opening, brake pedal opening, current gear, vehicle operating mode of the previous control cycle, and ABS activation signal, are acquired in real time, and the vehicle is then judged whether to enter or maintain coasting mode based on the driving parameters.

[0009] In coasting mode, the recovery intensity level is calculated based on the vehicle mass and road slope, and the target coasting recovery torque is calculated based on the recovery intensity level.

[0010] The target coasting recovery torque is output to the motor controller, which then performs braking control on the motor.

[0011] Furthermore, the vehicle operating modes include: drive mode, braking mode, cruise mode, and coasting mode.

[0012] Furthermore, the method for determining whether to enter or maintain gliding mode includes: entering or maintaining gliding mode if the following five conditions are met simultaneously:

[0013] Condition 1: Accelerator pedal opening is zero;

[0014] Condition 2: The brake pedal opening is zero;

[0015] Condition 3: The gear is in D mode;

[0016] Condition 4: The vehicle's operating mode in the previous control cycle was drive mode;

[0017] Condition 5: ABS did not function.

[0018] Furthermore, the calculation method for the recycling intensity level includes:

[0019] Obtain vehicle mass and road slope;

[0020] Determine the vehicle quality level based on vehicle quality;

[0021] Determine the road surface slope grade based on the road surface slope;

[0022] The recycling strength grade is calculated based on the vehicle quality grade and the road surface slope grade.

[0023] Furthermore, methods for determining vehicle quality grades based on vehicle mass include:

[0024] If 0 <m<30%*m max If so, the vehicle's mass rating is light load;

[0025] If 30%*m max ≤m≤70%*m max If so, the vehicle's mass rating is medium load;

[0026] If m > 70% * m max If so, the vehicle's mass rating is heavy-duty;

[0027] Where m is the vehicle mass, m max The full load weight of the vehicle;

[0028] Methods for determining road slope grade based on road surface slope include:

[0029] If α < -10% * α max If so, the road surface slope grade is uphill;

[0030] If -10%*α max ≤α<30%*α max If so, the road surface slope grade is a gentle slope;

[0031] If 30%*α max ≤α≤70%*α max The road surface slope grade is then medium slope.

[0032] If α > 70% * α max If so, the road surface slope grade is a steep slope;

[0033] Where α is the road surface slope, α max This represents the maximum slope.

[0034] The method for calculating the recovery strength grade based on vehicle mass grade and road slope grade includes: setting the vehicle mass grade values ​​x for light load, medium load and heavy load to 0, 1 and 2 respectively;

[0035] Set the road surface slope grade values ​​y to 0, 1, 2, and 3 for uphill, gentle slope, medium slope, and steep slope, respectively; calculate the recovery strength grade value using the following formula:

[0036]

[0037] In the formula, L V This refers to the strength rating value for recycling.

[0038] Furthermore, the calculation method for the target coasting recovery torque includes:

[0039] Based on the vehicle's full load mass m max Maximum slope α max Maximum gliding deceleration a max Calculate the maximum required braking force F of the vehicle max The formula is as follows:

[0040] F max =m max ×a max +m max ×g×sinα max -F W -F f (2)

[0041] In the formula, F W For vehicle air resistance, F f F is the rolling resistance of the vehicle. W F f Calculated based on empirical formulas;

[0042] The maximum recovery intensity coasting torque T is calculated based on the vehicle's maximum required braking force. max The formula is as follows:

[0043]

[0044] In the formula, R is the rolling radius of the wheel, i q Main reducer speed ratio, i t η is the gearbox ratio, and η is the transmission efficiency;

[0045] The target coasting recovery torque T is calculated based on the maximum recovery intensity coasting torque and the recovery intensity level. req The formula is as follows:

[0046]

[0047] In the formula, L V For the recovery strength grade value, L V-max This represents the maximum value for the recycling strength rating.

[0048] Furthermore, the method also includes: when the vehicle is in coasting mode, if the target coasting recovery torque is greater than 0, the gear shifting operation is prohibited; otherwise, the transmission controller is allowed to perform gear shifting according to the gear shifting control logic.

[0049] Furthermore, the method also includes distance and speed correction for the target coasting recovery torque, as follows:

[0050] The distance d between the obstacle ahead and the vehicle is obtained from the obstacle detection system, and the distance correction factor f1 is calculated using the following formula:

[0051]

[0052] In the formula, d1 and d2 are the near-range threshold and the far-range threshold, respectively. max This represents the maximum detection range of the obstacle detection system.

[0053] Obtain the vehicle speed v, and calculate the vehicle speed correction factor f2 using the following formula:

[0054]

[0055] In the formula, v1 and v2 are the low-speed threshold and the high-speed threshold, respectively;

[0056] The target coasting recovery torque is corrected using the following formula:

[0057]

[0058] In the formula, The corrected target coasting recovery torque.

[0059] Furthermore, if the calculated target coasting recovery torque is greater than the maximum recovery torque limit T... limit Then set the target coasting recovery torque to T. limit ;T limit This refers to the minimum values ​​of the mechanical shaft reverse drag limiting torque, the limiting torque under energy management recyclable power, and the maximum braking limiting torque of the motor.

[0060] Secondly, the present invention provides a coasting recovery torque control device based on operating condition adaptation, comprising:

[0061] The mode determination module is used to acquire vehicle driving parameters in real time, including accelerator pedal opening, brake pedal opening, current gear, vehicle operating mode of the previous control cycle, and ABS action signal, and determine whether to enter or maintain coasting mode based on the driving parameters.

[0062] The torque calculation module is used to calculate the recovery intensity level based on the vehicle mass and road slope in coasting mode, and to calculate the target coasting recovery torque based on the recovery intensity level.

[0063] The torque output module is used to output the target coasting recovery torque to the motor controller, which then performs braking control on the motor.

[0064] Compared with the prior art, the present invention has the following beneficial effects.

[0065] (1) This invention takes into account the influence of vehicle mass and road slope on coasting recovery torque control, and reduces the sensitivity of mass and slope parameters by reasonable interval division;

[0066] (2) By controlling the gear shifting operation of the transmission, the present invention avoids downshifting during coasting recovery, thereby improving the efficiency of coasting recovery and enhancing the driving experience during coasting recovery.

[0067] (3) The present invention can still provide a relatively comfortable gliding deceleration when going downhill, which improves the braking safety of the vehicle in different operating scenarios compared with the existing uniform speed gliding downhill technology.

[0068] (4) This invention takes into account vehicle parameters such as vehicle speed, forward obstacle detection, and torque limitation, and provides an easy-to-implement adaptive coasting recovery torque control method. Attached Figure Description

[0069] Figure 1 This is a flowchart of a coasting recovery torque control method based on adaptive operating conditions, according to an embodiment of the present invention.

[0070] Figure 2 This is a schematic diagram of the hardware module structure involved in the present invention.

[0071] Figure 3 This is a block diagram of a coasting recovery torque control device based on adaptive operating conditions, according to an embodiment of the present invention. Detailed Implementation

[0072] To make the objectives, technical solutions, and advantages of this invention clearer and more understandable, the invention will be further described below in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0073] Figure 1 This is a flowchart of a coasting recovery torque control method based on adaptive operating conditions according to an embodiment of the present invention, including the following steps executed in the vehicle controller:

[0074] Step 101: Real-time acquisition of vehicle driving parameters including accelerator pedal opening, brake pedal opening, current gear, vehicle operating mode of the previous control cycle, and ABS activation signal; and determination of whether to enter or maintain coasting mode based on the driving parameters.

[0075] Step 102: In coasting mode, calculate the recovery intensity level based on the vehicle mass and road slope, and calculate the target coasting recovery torque based on the recovery intensity level;

[0076] Step 103: The target coasting recovery torque is output to the motor controller, which then performs braking control on the motor.

[0077] This embodiment provides a coasting recovery torque control method based on adaptive operating conditions, and the hardware module structure involved is as follows: Figure 2 As shown, the system includes an obstacle detection system, an ABS (Anti-lock Braking System) controller, a vehicle control unit (VCU), a transmission control unit (TCU), a motor control unit (MCU), an accelerator pedal, a brake pedal, a gear shift lever, a motor, and a battery. The VCU obtains forward obstacle information from the obstacle detection system via the CAN bus and ABS validity identification information from the ABS controller. It controls the gear shifting operations of the transmission control unit (TCU) and the torque of the motor control unit (MCU) to achieve energy recovery during coasting. The transmission control unit (TCU) is not a mandatory component; the gear shifting process can also be controlled through the VCU. The method described in this embodiment is implemented by the VCU repeatedly executing steps 101-103. Steps 101-103 are the operations performed in one control cycle, with a typical control cycle duration of 10ms. Steps 101-103 are described below.

[0078] In this embodiment, step 101 is mainly used to determine whether the vehicle operating mode has entered or remains in coasting mode. This embodiment makes this determination based on real-time acquired vehicle driving parameters, including accelerator pedal opening, brake pedal opening, current gear, vehicle operating mode of the previous control cycle, and ABS activation signal. When the driving parameters meet the conditions for coasting mode, if the current mode is not coasting mode, it switches to coasting mode; if the current mode is coasting mode, it remains unchanged. Accelerator pedal opening (0-100%) is obtained from the accelerator pedal, brake pedal opening (0-100%) is obtained from the brake pedal, gear signals (N, D, and R) are obtained from the gear shift lever, the vehicle operating mode of the previous moment is obtained from the VCU internal memory, and the ABS activation signal is obtained from the CAN signal message (J1939 protocol) of the ABS controller.

[0079] In this embodiment, step 102 is mainly used to calculate the target coasting recovery torque. The target coasting recovery torque is the real-time control torque (i.e., braking torque) of the motor in coasting mode. This embodiment automatically adjusts the magnitude of the target coasting recovery torque based on the real-time acquired vehicle mass and road slope. This embodiment calculates the recovery intensity level based on the vehicle mass and road slope to obtain a quantified recovery intensity level value, and calculates the target coasting recovery torque based on the level value, that is, the target coasting recovery torque is proportional to the level value. Generally speaking, the greater the vehicle mass and the steeper the road slope (downhill), the higher the recovery intensity level. The vehicle mass is known when unloaded, but in reality, vehicles mostly operate under loaded conditions, so it is necessary to estimate the vehicle mass. There are many methods for estimating vehicle mass. For example, during the vehicle start-up phase, it can be calculated using Newton's second law using the formula F. 驱 -F阻 =ma is a rough calculation of the vehicle's mass, where a is the acceleration value obtained from the accelerometer. Road surface slope can be obtained by installing a slope sensor.

[0080] In this embodiment, step 103 is mainly used to output the target coasting recovery torque. This embodiment outputs the target coasting recovery torque to the motor controller (MCU), which then controls the braking of the motor. The coasting control method of this embodiment can still provide a relatively comfortable coasting deceleration when going downhill, improving the braking safety of the vehicle in different operating scenarios compared to existing constant-speed coasting downhill techniques.

[0081] As an optional embodiment, the vehicle operating modes include: driving mode, braking mode, cruise mode, and coasting mode.

[0082] This embodiment illustrates several commonly used vehicle operating modes. These modes include drive mode, braking mode, cruise mode, and coasting mode. Drive mode is characterized by an accelerator pedal opening greater than zero, indicating the vehicle is accelerating. Braking mode is characterized by a brake pedal opening greater than zero, indicating the vehicle is braking. Cruise mode is characterized by both accelerator and brake pedal openings being zero, indicating the vehicle is traveling at a constant speed. Coasting mode is characterized by the vehicle being in a free-gliding state, such as when going downhill or driving on ice.

[0083] As an optional embodiment, the method for determining whether to enter or maintain the gliding mode includes: entering or maintaining the gliding mode if the following five conditions are met simultaneously:

[0084] Condition 1: Accelerator pedal opening is zero;

[0085] Condition 2: The brake pedal opening is zero;

[0086] Condition 3: The gear is in D mode;

[0087] Condition 4: The vehicle's operating mode in the previous control cycle was drive mode;

[0088] Condition 5: ABS did not function.

[0089] This embodiment provides the criteria for determining the coasting mode. The criteria for determining the coasting mode in this embodiment require the simultaneous fulfillment of the five conditions mentioned above. If any one condition is not met, the vehicle cannot enter or exit the coasting mode. Existing determination methods generally do not include condition 4. The purpose of adding condition 4 in this embodiment is to prevent frequent ABS triggering during ice surface coasting recovery, which could cause vehicle jerking and improve comfort. The technical principle is as follows: When the vehicle is traveling on surfaces with very low friction coefficients, such as ice, if the previous control cycle was in braking mode, emergency braking may have already triggered the ABS controller's anti-lock braking system. If the vehicle exits braking mode and enters coasting mode at this time, the presence of electric braking recovery in coasting mode may trigger the ABS again, and the electric braking will disengage after the ABS is triggered. Repeated triggering of the ABS will cause vehicle jerking. By adding the condition that the previous control cycle was in driving mode, it is possible to avoid triggering the ABS again after emergency braking has already triggered it.

[0090] As an optional embodiment, the method for calculating the recycling intensity level includes:

[0091] Obtain vehicle mass and road slope;

[0092] Determine the vehicle quality level based on vehicle quality;

[0093] Determine the road surface slope grade based on the road surface slope;

[0094] The recycling strength grade is calculated based on the vehicle quality grade and the road surface slope grade.

[0095] This embodiment provides a technical solution for calculating the recycling intensity level. First, the current vehicle weight and road surface slope are obtained using the aforementioned method. Then, the vehicle weight level and road surface slope level are determined based on the vehicle weight and road surface slope (divided into different intervals). Different level thresholds (interval endpoint values) can be preset. By comparing the vehicle weight and road surface slope with the preset thresholds, the vehicle weight level and road surface slope level are obtained. Finally, the recycling intensity level is calculated based on the vehicle weight level and road surface slope level. Generally, the higher the vehicle weight level and road surface slope level, the higher the recycling intensity level.

[0096] As an optional embodiment, the method for determining a vehicle quality grade based on vehicle quality includes:

[0097] If 0 <m<30%*m max If so, the vehicle's mass rating is light load;

[0098] If 30%*m max ≤m≤70%*m max If so, the vehicle's mass rating is medium load;

[0099] If m > 70% * m max If so, the vehicle's mass rating is heavy-duty;

[0100] Where m is the vehicle mass, m max The full load weight of the vehicle;

[0101] Methods for determining road slope grade based on road surface slope include:

[0102] If α < -10% * α max If so, the road surface slope grade is uphill;

[0103] If -10%*α max ≤α<30%*α max If so, the road surface slope grade is a gentle slope;

[0104] If 30%*α max ≤α≤70%*α max The road surface slope grade is then medium slope.

[0105] If α > 70% * α max If so, the road surface slope grade is a steep slope;

[0106] Where α is the road surface slope, α max This represents the maximum slope.

[0107] Methods for calculating the recovery strength grade based on vehicle mass grade and road slope grade include:

[0108] The vehicle mass class values ​​x for light load, medium load, and heavy load are set to 0, 1, and 2, respectively.

[0109] The road surface slope grades y are set to 0, 1, 2, and 3 for uphill, gentle slope, medium slope, and steep slope, respectively.

[0110] Calculate the recycling strength rating using the following formula:

[0111]

[0112] In the formula, LV represents the recycling intensity level value.

[0113] This embodiment provides a technical solution for calculating the quantified value of the recycling intensity level. First, vehicle weight is divided into three levels: light load, medium load, and heavy load, according to the order of increasing vehicle weight. Road slope is divided into four levels: uphill (uphill slope is negative, downhill slope is positive), small slope, medium slope, and large slope, according to the order of increasing road slope. Then, the three vehicle weight levels are quantified as 0, 1, and 2, respectively, and the four road slope levels are quantified as 0, 1, 2, and 3, respectively. Finally, a quantification model for the recycling intensity level is given, namely formula (1). Substituting the quantified value of the vehicle weight level x and the quantified value of the road slope level y into the quantification model, the quantified value of the recycling intensity level LV is obtained. The quantification model is a piecewise function. When y = 0, L V =0; when y≠0, L V =x + y. Recycling intensity level L V The values ​​are 0, 1, 2, 3, 4, and 5.

[0114] It is worth noting that this embodiment only provides a preferred implementation method and does not negate or exclude other feasible implementation methods. In fact, there can be many different quantification methods. For example, vehicle mass grades and road slope grades can be divided into more finer categories to obtain more recycling intensity grades. It is even possible to calculate the recycling intensity influence coefficient directly based on the values ​​of vehicle mass and road slope (continuous quantities) without classifying the grades. Of course, the finer the classification, the higher the accuracy requirements for mass and slope parameters.

[0115] As an optional embodiment, the method for calculating the target coasting recovery torque includes:

[0116] Based on the vehicle's full load mass m max Maximum slope α max Maximum gliding deceleration a max Calculate the maximum required braking force F of the vehicle max The formula is as follows:

[0117] F max =m max ×a max +m max ×g×sinα max -FW-F f (2)

[0118] In the formula, F W For vehicle air resistance, F f F is the rolling resistance of the vehicle. W F f Calculated based on empirical formulas;

[0119] The maximum recovery intensity coasting torque T is calculated based on the vehicle's maximum required braking force. max The formula is as follows:

[0120]

[0121] In the formula, R is the rolling radius of the wheel, i q Main reducer speed ratio, i t η is the gearbox ratio, and η is the transmission efficiency;

[0122] The target coasting recovery torque T is calculated based on the maximum recovery intensity coasting torque and the recovery intensity level. req The formula is as follows:

[0123]

[0124] In the formula, L V For the recovery strength grade value, L V-max This represents the maximum value for the recycling strength rating.

[0125] This embodiment presents a technical solution for calculating the target coasting recovery torque. First, based on the principles of mechanics, the maximum required braking force of the vehicle is calculated using the vehicle's full load mass, maximum gradient, and maximum coasting deceleration, as shown in equation (2). Where F W For vehicle air resistance, F f F is the rolling resistance of the vehicle. W F f Based on empirical formulas, the calculation formula is as follows:

[0126]

[0127] F f =m×g×f×cosα max

[0128] In the formula, C D Let A be the vehicle's drag coefficient, V be the vehicle's frontal area, v be the vehicle speed, and f be the rolling friction coefficient of the wheels.

[0129] Then, calculate the maximum recovery strength sliding torque T according to formula (3). max Finally, the target coasting recovery torque is calculated according to formula (4) based on the maximum recovery intensity coasting torque and the recovery intensity level. In formula (4), L... V / L V-max To recover the normalized value of the intensity level, L in the previous embodiment V-max =5.

[0130] As an optional embodiment, the method further includes: when the vehicle is in coasting mode, if the target coasting recovery torque is greater than 0, the gear shifting operation is prohibited; otherwise, the transmission controller is allowed to perform gear shifting according to the gear shifting control logic.

[0131] This embodiment provides a technical solution for shift control in the coasting mode. When the vehicle operating mode is the coasting mode, if the target coasting recovery torque is greater than 0, the shift operation is prohibited; otherwise, the transmission controller performs the shift operation according to the shift control logic. By controlling the shift operation of the transmission, this embodiment can avoid downshifting during the coasting recovery process, enhance the coasting recovery efficiency, and improve the driving experience during the coasting recovery process.

[0132] As an optional embodiment, the method further includes distance correction and vehicle speed correction for the target coasting recovery torque, and the method is as follows:

[0133] Obtain the distance d between the vehicle and the obstacle ahead from the obstacle detection system, and calculate the distance correction coefficient f1 according to the following formula:

[0134]

[0135] In the formula, d1 and d2 are the short-distance threshold and the long-distance threshold respectively, and d max is the maximum detection distance of the obstacle detection system;

[0136] Obtain the vehicle speed v, and calculate the vehicle speed correction coefficient f2 according to the following formula:

[0137]

[0138] In the formula, v1 and v2 are the low-speed threshold and the high-speed threshold respectively;

[0139] Correct the target coasting recovery torque according to the following formula:

[0140]

[0141] In the formula, is the corrected target coasting recovery torque.

[0142] This embodiment provides a technical solution for correcting (compensating) the target coasting recovery torque. The correction includes distance correction and vehicle speed correction.

[0143] The distance refers to the distance d between the vehicle and the obstacle ahead. The distance correction divides the correction coefficient f1 into three intervals according to the magnitude of the distance d: when d < d1, to enhance the coasting recovery, the correction coefficient f1 > 1; when d > d2, to reduce the coasting recovery, the correction coefficient f1 < 1; when d1 ≤ d ≤ d2, for normal coasting recovery, the correction coefficient f1 = 1. The specific correction coefficient values and interval ranges can be calibrated according to the actual vehicle conditions and usage scenario requirements. Formula (5) gives a specific model. d1 is not less than the shortest emergency braking distance of the vehicle, and d2 is close to the maximum detection distance d of the obstacle detection system max。Typical values of d1 and d2 are 50m and 200m respectively. In this embodiment, without the user's active operation intention, stronger braking recovery ability can be provided in advance according to the working conditions, which improves the energy recovery efficiency and braking safety to a certain extent, and reduces the braking system loss caused by the user's subsequent braking operation intervention.

[0144] The vehicle speed correction divides the vehicle speed correction coefficient f2 into three intervals according to the magnitude of the current vehicle speed v: when v < v1, the coasting recovery is cancelled, and the correction coefficient f2 = 0; when v1 ≤ v ≤ v2, the coasting recovery is reduced, and the correction coefficient 0 < f2 < 1; when v > v2, the coasting recovery is maintained, and the correction coefficient f2 = 1. Formula (6) gives a specific model. The magnitudes of v1 and v2 are calibrated according to the vehicle speed operating working points of the target vehicle model, and the typical values are 15km / h and 25km / h respectively.

[0145] As an optional embodiment, if the calculated target coasting recovery torque is greater than the maximum recovery torque limit value T limit , the target coasting recovery torque is set to T limit ; T limit is the minimum value of the mechanical shaft back-dragging limit torque, the limit torque under the recoverable power of energy management, and the maximum motor braking limit torque.

[0146] This embodiment limits the maximum value of the target coasting recovery torque. This embodiment sets that the maximum value of the target coasting recovery torque cannot exceed the limit value T limit , when the calculated coasting recovery torque is greater than T limit , the coasting recovery torque is "limited" to T limit . T limit takes the minimum value of 3 limit torques. The 3 limit torques are the mechanical shaft back-dragging limit torque, the limit torque under the recoverable power of energy management, and the maximum motor braking limit torque. The mechanical shaft back-dragging limit torque is equal to the ratio of the torque limit T of the mechanical shaft itself to the current transmission ratio i t of T / i t ; the limit torque under the recoverable power of energy management is estimated according to the current battery charging ability, accessory power, etc. The accessory power is the power consumed by non-vehicle driving power equipment such as compressors, water pumps, fans, and headlights when the electric vehicle is running; the maximum motor braking limit torque is obtained by judging according to the fault level and temperature of the MCU or directly obtained from the message information of the MCU.

[0147] Figure 3 is a schematic diagram of the composition of a coasting recovery torque control device based on working condition adaptation according to an embodiment of the present invention. The device includes:

[0148] The mode determination module 11 is used to acquire in real time the vehicle's driving parameters, including accelerator pedal opening, brake pedal opening, current gear, vehicle operating mode of the previous control cycle, and ABS action signal, and determine whether to enter or maintain coasting mode based on the driving parameters.

[0149] The torque calculation module 12 is used to calculate the recovery intensity level based on the vehicle mass and road slope in coasting mode, and to calculate the target coasting recovery torque based on the recovery intensity level.

[0150] The torque output module 13 is used to output the target coasting recovery torque to the motor controller, which then performs braking control on the motor.

[0151] The apparatus of this embodiment can be used to perform Figure 1 The technical solutions of the method embodiments shown are similar in principle and in effect, and will not be described again here.

[0152] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A coasting recovery torque control method based on adaptive operating conditions, characterized in that, This includes the following steps performed in the vehicle controller: Real-time acquisition of driving parameters including accelerator pedal opening, brake pedal opening, current gear, vehicle operating mode of the previous control cycle, and ABS activation signal; and determination of whether to enter or maintain coasting mode based on the driving parameters. In coasting mode, the recovery intensity level is calculated based on the vehicle mass and road slope, and the target coasting recovery torque is calculated based on the recovery intensity level; it also includes: when the vehicle is in coasting mode, if the target coasting recovery torque is greater than 0, shifting is prohibited; otherwise, the transmission controller is allowed to shift gears according to the shift control logic; The target coasting recovery torque is output to the motor controller, which then performs braking control on the motor.

2. The coasting recovery torque control method based on adaptive operating conditions according to claim 1, characterized in that, Vehicle operating modes include: drive mode, braking mode, cruise mode, and coasting mode.

3. The coasting recovery torque control method based on adaptive operating conditions according to claim 2, characterized in that, The method for determining whether to enter or maintain gliding mode includes: if the following five conditions are met simultaneously, then gliding mode will be entered or maintained: Condition 1: Accelerator pedal opening is zero; Condition 2: The brake pedal opening is zero; Condition 3: The gear is in D mode; Condition 4: The vehicle's operating mode in the previous control cycle was drive mode; Condition 5: ABS did not function.

4. The coasting recovery torque control method based on adaptive operating conditions according to claim 1, characterized in that, The methods for calculating recycling intensity grades include: Obtain vehicle mass and road slope; Determine the vehicle quality level based on vehicle quality; Determine the road surface slope grade based on the road surface slope; The recycling strength grade is calculated based on the vehicle quality grade and the road surface slope grade.

5. The coasting recovery torque control method based on adaptive operating conditions according to claim 4, characterized in that, Methods for determining vehicle quality grades based on vehicle quality include: If 0 <m<30%*m max If so, the vehicle's mass rating is light load; If 30%*m max ≤m≤70%*m max If so, the vehicle's mass rating is medium load; If m > 70%*m max If so, the vehicle's mass rating is heavy-duty; Where m is the vehicle mass, m max The full load weight of the vehicle; Methods for determining road slope grade based on road surface slope include: If α < -10%*α max If so, the road surface slope grade is uphill; If -10%*α max ≤α<30%*α max If so, the road surface slope grade is a gentle slope; If 30%*α max ≤α≤70%*α max The road surface slope grade is then medium slope. If α > 70%*α max If so, the road surface slope grade is a steep slope; Where α is the road surface slope, α max This represents the maximum slope. Methods for calculating the recovery strength grade based on vehicle mass grade and road slope grade include: The vehicle mass class values ​​x for light load, medium load, and heavy load are set to 0, 1, and 2, respectively. The road surface slope grades y are set to 0, 1, 2, and 3 for uphill, gentle slope, medium slope, and steep slope, respectively. Calculate the recycling strength rating using the following formula: （1） In the formula, L V This refers to the strength rating value for recycling.

6. The coasting recovery torque control method based on adaptive operating conditions according to claim 1, characterized in that, The methods for calculating the target coasting recovery torque include: Based on the vehicle's full load mass m max Maximum slope α max Maximum gliding deceleration a max Calculate the maximum required braking force F of the vehicle max The formula is as follows: F max =m max ×a max +m max ×g×sinα max -F W -F f (2) In the formula, F W For vehicle air resistance, F f F is the rolling resistance of the vehicle. W F f Calculated based on empirical formulas; The maximum recovery intensity coasting torque T is calculated based on the vehicle's maximum required braking force. max The formula is as follows: （3） In the formula, R is the rolling radius of the wheel, i q Main reducer speed ratio, i t η is the gearbox ratio, and η is the transmission efficiency; The target coasting recovery torque T is calculated based on the maximum recovery intensity coasting torque and the recovery intensity level. req The formula is as follows: （4） In the formula, L V For the recovery strength grade value, L V-max This represents the maximum value for the recycling strength rating.

7. The coasting recovery torque control method based on adaptive operating conditions according to claim 6, characterized in that, The method also includes distance and speed correction for the target coasting recovery torque, as follows: The distance d between the obstacle ahead and the vehicle is obtained from the obstacle detection system, and the distance correction factor f1 is calculated using the following formula: （5） In the formula, d1 and d2 are the near-range threshold and the far-range threshold, respectively. max This represents the maximum detection range of the obstacle detection system. Obtain the vehicle speed v, and calculate the vehicle speed correction factor f2 using the following formula: （6） In the formula, v1 and v2 are the low-speed threshold and the high-speed threshold, respectively; The target coasting recovery torque is corrected using the following formula: （7） In the formula, The corrected target coasting recovery torque.

8. The coasting recovery torque control method based on adaptive operating conditions according to claim 1, characterized in that, If the calculated target recovery torque is greater than the maximum recovery torque limit T limit Then set the target coasting recovery torque to T. limit ;T limit This refers to the minimum values ​​of the mechanical shaft reverse drag limiting torque, the limiting torque under energy management recyclable power, and the maximum braking limiting torque of the motor.

9. A coasting recovery torque control device based on adaptive operating conditions, characterized in that, include: The mode determination module is used to acquire vehicle driving parameters in real time, including accelerator pedal opening, brake pedal opening, current gear, vehicle operating mode of the previous control cycle, and ABS action signal, and determine whether to enter or maintain coasting mode based on the driving parameters. The torque calculation module is used to calculate the recovery intensity level based on the vehicle mass and road slope in coasting mode, and to calculate the target coasting recovery torque based on the recovery intensity level. When the vehicle is in coasting mode, if the target coasting recovery torque is greater than 0, shifting is prohibited; otherwise, the transmission controller is allowed to shift gears according to the shift control logic. The torque output module is used to output the target coasting recovery torque to the motor controller, which then performs braking control on the motor.

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