CN114987483A - Sliding feedback self-adaptive degradation control method and system for electric vehicle - Google Patents
Sliding feedback self-adaptive degradation control method and system for electric vehicle Download PDFInfo
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Abstract
The invention provides a sliding feedback self-adaptive degradation control method and a sliding feedback self-adaptive degradation control system for an electric vehicle, and relates to the technical field of vehicle energy recovery. The invention discloses a sliding feedback self-adaptive degradation control method of an electric vehicle, which comprises the following steps: collecting state data indicating the state of the vehicle; judging whether the vehicle meets a first condition or not according to the state data; under the condition that the vehicle meets the first condition, judging whether the vehicle meets a second condition; and in the case that the vehicle meets the second condition, controlling the coasting feedback level of the vehicle to be reduced by one step or kept at the lowest level. The first condition is that the vehicle is in a driving state, the vehicle is in a D/R gear, the reference vehicle speed of the vehicle exceeds a preset value, the vehicle is not braked and the vehicle is in a feedback state. The second condition is one selected from the group consisting of an estimated calculated ground adhesion coefficient being less than a preset value and exceeding a first preset time, a wheel tendency to a locked state, or an ABS activation. The invention can reasonably utilize the road surface attachment to feed back for power generation, the driving feeling is smoother, and the pure electric endurance is improved.
Description
The application is CN202010986847.7 filed on 18.9.2020 and entitled "adaptive sliding feedback degradation control method and control system for electric vehicle".
Technical Field
The invention relates to the technical field of vehicle energy recovery, in particular to a sliding feedback self-adaptive degradation control method and a sliding feedback self-adaptive degradation control system for an electric vehicle.
Background
Most of current new energy vehicle types adopt a fuel door to perform sliding feedback to charge a high-voltage storage battery by using deceleration efficiency so as to improve the endurance mileage or fuel economy of the vehicle, and provide various sliding feedback levels such as strong, medium and weak levels for a user to select so as to match diversified requirements of the user, wherein the maximum deceleration of the sliding feedback under the strong level can reach more than 0.2 g. However, when a vehicle slides under certain special working conditions (such as ice, snow, wet and slippery road surfaces and high-low adhesion alternate road surfaces), the wheel locking is easily caused to activate the ABS due to the fact that the sliding feedback torque is large because the adhesive force of the low-slide road surface is small.
Currently, the common operation of a large number of vehicle enterprises is to cancel sliding feedback immediately when detecting ABS activation; and the ABS exits, and the sliding feedback is recovered in a delayed mode. Or an experienced chassis brake supplier is used for making a wheel locking correction factor for the feedback torque, and when the wheel is detected to be locked, the sliding feedback torque is reduced to enable the wheel to be recovered to be normal.
The method for canceling the sliding feedback, quitting the ABS and recovering the sliding feedback in a delayed manner is adopted to disable the feedback at once, although the feedback locking problem can be solved to a certain extent, the driver is uncomfortable due to sudden change of the deceleration feeling during sliding easily occurs, and the road load is not effectively utilized to feed back the power generation.
And an experienced chassis brake supplier is used for making a wheel locking correction factor for the feedback torque, and when the wheel is detected to be locked, the sliding feedback torque is reduced to enable the wheel to be recovered to be normal. Firstly, although the road surface attachment feedback can be utilized to the maximum extent, the matching difficulty is high, and the technical level and the matching strength of a chassis brake supplier are relatively depended. Secondly, because the wheel locking correction factor is calculated in real time according to the wheel speed condition, the influence of road surface fluctuation is large, and the high-low alternate road surface is easy to cause large time and small time when the feedback torque is fed back, so that the driving feeling is poor.
Disclosure of Invention
An object of the first aspect of the present invention is to provide a method and a system for controlling adaptive degradation of coasting feedback of an electric vehicle, which solve the problem of poor driving feeling caused by canceling coasting feedback by activating an ABS in the prior art;
another object of the first aspect of the present invention is to solve the problem of frequent ABS activation due to excessive wheel locking due to feedback in the prior art.
Still another object of the first aspect of the present invention is to solve the problem that the current system is greatly affected by fluctuations in road surface conditions and the driving feeling is poor.
It is an object of a second aspect of the present invention to provide a coasting feedback adaptive degradation control system for an electric vehicle.
According to a first aspect of the present invention, there is provided a coasting feedback adaptive degradation control method for an electric vehicle, the electric vehicle having at least two different coasting feedback levels, the coasting feedback adaptive degradation control method for the electric vehicle comprising:
collecting state data representing the state of the electric vehicle;
judging whether the vehicle meets a first condition or not according to the state data;
under the condition that the vehicle meets the first condition, judging whether the vehicle meets a second condition or not;
controlling a coasting feedback level of the vehicle to be reduced by one level or maintained at a minimum level if the vehicle satisfies the second condition;
wherein the first condition is that the vehicle is in a drivable state, the vehicle is in a D/R gear, a reference vehicle speed of the vehicle exceeds a predetermined value, the vehicle is in an unbraked state, and the vehicle is in a regenerative state;
the second condition is any one selected from the group consisting of a time at which the estimated ground adhesion coefficient is less than a preset value and the estimated ground adhesion coefficient is less than the preset value exceeding a first preset time, a wheel tendency to a locked state, or an ABS activation.
Optionally, the method further comprises:
judging whether a third condition is met, and if the third condition is met, recovering the sliding feedback grade of the vehicle, wherein the third condition comprises any one of the following conditions:
the driver demand torque is positive; or
The vehicle is in P/N gear.
Optionally, after determining whether the third condition is satisfied, the method further includes:
outputting a feedback output grade of the vehicle according to whether the vehicle meets the second condition, whether the vehicle meets the third condition and the preselected feedback grade, wherein the feedback output grade is the feedback grade actually output by the vehicle;
requesting the vehicle to output corresponding feedback torque according to the feedback output grade;
when the vehicle meets the third condition, the feedback output level of the vehicle is an initial feedback level, and the initial feedback level is a preselected feedback level;
when the vehicle does not satisfy the third condition but satisfies the second condition, the feedback output level of the vehicle is selected to be lower than the feedback level which is degraded and is compared with the preselected feedback level to take a smaller level;
when the vehicle does not satisfy either the third condition or the second condition, the feedback output level of the vehicle is selected from the lower of the feedback output levels output by the vehicle that will maintain the degraded feedback level compared to the preselected feedback level;
and repeating the judgment of the second condition and the third condition after the feedback output level is degraded.
Optionally, after the coasting level of the vehicle is decreased by one step downwards, whether the vehicle meets the first condition and the second condition is judged again, and when the vehicle meets the first condition and the second condition is judged, the coasting feedback level of the vehicle is continuously decreased by one step downwards;
and repeating the process until the sliding feedback grade is 0 grade.
Optionally, the estimated ground adhesion coefficient is less than a preset value, which is the smaller of the estimated ground adhesion coefficient and a first set value and a second set value, wherein the first set value x1 ═ g1|/g) + s, and the second set value x2 ═ T |/(F r × g) + s;
where g1 is the deceleration corresponding to the current feedback level, g is the gravity deceleration, s is the offset, T is the feedback torque request, F is the vehicle weight, and r is the tire radius.
Optionally, the wheel is indicated to be locked when the following condition is met and the time for which the condition is met exceeds a second preset time:
the wheel speed is lower than the reference vehicle speed and the rate of change of the wheel speed is lower than a first threshold; or
The rate of change of wheel speed is below a second threshold, the first threshold and the second threshold are both negative values and the first threshold > the second threshold.
Alternatively, the ABS system of the vehicle is indicated to be activated when any of the following conditions is met:
the ABS system is continuously activated for more than a third set time;
and the time of the activation of the ABS system is accumulated to exceed a fourth set time.
Particularly low, the present invention also provides a coasting feedback adaptive degradation control system for an electric vehicle having at least two different coasting feedback levels, the control system comprising:
the acquisition module is used for acquiring state data which represents the state of the electric vehicle;
the first judging module is used for judging whether the vehicle meets a first condition or not according to the state data;
the second judgment module is used for judging whether the vehicle meets a second condition or not under the condition that the vehicle meets the first condition; and
the control module is used for controlling the coasting feedback level of the vehicle to be reduced by one level or kept at the lowest level under the condition that the vehicle meets the second condition;
wherein the first condition is that the vehicle is in a drivable state, the vehicle is in a D/R gear, a reference vehicle speed of the vehicle exceeds a predetermined value, the vehicle is in an unbraked state, and a required torque of the vehicle is negative;
the second condition is any one selected from the group consisting of a time at which the estimated ground adhesion coefficient is less than a preset value and the estimated ground adhesion coefficient is less than the preset value exceeding a first preset time, a wheel tendency to a locked state, or an ABS activation.
The control system further comprises a feedback grade recovery module, wherein the grade recovery module is used for judging whether a third condition is met, and recovering the sliding feedback grade of the vehicle when the following third condition is met, and the third condition comprises any one of the following conditions:
the driver demand torque is positive; or
The vehicle is in P/N gear.
The control system further comprises:
a feedback grade output module for outputting a feedback output grade of the vehicle according to whether the vehicle satisfies the second condition, whether the vehicle satisfies the third condition, and the preselected feedback grade, wherein the feedback output grade is an actually output feedback grade of the vehicle; and
the torque request module is used for requesting the vehicle to output corresponding feedback torque according to the feedback output grade;
when the vehicle meets the third condition, the feedback output level of the vehicle is an initial feedback level, and the initial feedback level is a preselected feedback level;
when the vehicle does not satisfy the third condition but satisfies the second condition, the feedback output level of the vehicle is selected to be lower than the feedback level which is degraded and is compared with the preselected feedback level to take a smaller level;
when the vehicle does not satisfy either the third condition or the second condition, the feedback output level of the vehicle is selected from the lower of the feedback output levels output by the vehicle that will maintain the degraded feedback level compared to the preselected feedback level;
and repeating the judgment of the second condition and the third condition after the feedback output level is degraded.
According to the method, after the vehicle is judged to meet the first condition and the second condition, the vehicle performs the degradation processing of the sliding feedback. In the second condition, when the ABS of the vehicle is activated, the sliding feedback is not directly exited but only degraded, so that the driver is not uncomfortable due to sudden change of the deceleration feeling of the vehicle during sliding, the road load is effectively utilized to feed back the power generation, and the method is better than the method for directly canceling the feedback in the prior art. In addition, in the application, when the ABS is activated, the feedback torque is reduced step by step and waiting time is reserved, so that compared with the situation that the deceleration feeling is suddenly lost when the feedback torque is directly cancelled, the driving feeling is smoother.
When the ABS is activated or the wheel is detected to be close to the locking limit, the feedback torque of a feedback grade is reduced to judge whether the wheel locking is improved or not, if the feedback torque is effective, the current feedback grade is maintained, and the situation that the wheel is locked again after the ABS is withdrawn and the ABS is triggered is avoided. Compared with the prior art, the feedback is directly cancelled, and the ABS is not frequently activated.
The invention can reasonably recover the initial feedback grade by actively identifying the low-attachment road surface for feedback degradation, maintenance, acceleration and other working conditions through low-attachment calculation, wheel locking prejudgment, ABS activation prejudgment and the like without manual operation of a driver. Compared with the prior art, the method directly cancels feedback, can reasonably utilize the road surface attachment to feed back for power generation, and improves pure electric endurance.
The invention triggers feedback degradation under the single sliding feedback working condition through the fact that the ABS activation accumulated time exceeds the limit value or the ABS is continuously activated to exceed the limit value, and is compatible with typical working conditions such as continuous low-adhesion road surfaces (ice and snow wet sliding road surfaces) and discontinuous low-adhesion road surfaces (ice and snow chessboard road surfaces).
The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments thereof taken in conjunction with the accompanying drawings.
Drawings
Some specific embodiments of the invention will be described in detail hereinafter, by way of illustration and not limitation, with reference to the accompanying drawings. The same reference numbers in the drawings identify the same or similar elements or components. Those skilled in the art will appreciate that the drawings are not necessarily drawn to scale. In the drawings:
FIG. 1 is a schematic flow diagram of a coasting feedback adaptive degradation control method for an electric vehicle according to one embodiment of the present invention;
FIG. 2 is a flowchart illustrating exemplary steps for a coasting feedback adaptive degradation control method for an electric vehicle according to an embodiment of the present invention;
FIG. 3 is a schematic flow chart diagram of a coasting feedback adaptive degradation control method for an electric vehicle according to another embodiment of the present invention;
FIG. 4 is a flowchart illustrating exemplary steps of a coasting feedback adaptive degradation control method for an electric vehicle according to another embodiment of the present invention;
FIG. 5 is a schematic block diagram of a coasting feedback adaptive degradation control system of an electric vehicle in accordance with an embodiment of the present invention;
FIG. 6 is a schematic block diagram of an acquisition module and a data monitoring and calculation module of a coasting feedback adaptive degradation control system for an electric vehicle according to an embodiment of the present invention;
FIG. 7 is a schematic block diagram of a coasting feedback adaptive degradation control system of an electric vehicle according to another embodiment of the present invention.
Detailed Description
Fig. 1 is a schematic flow chart of a coasting feedback adaptive degradation control method of an electric vehicle according to an embodiment of the present invention. A coasting feedback adaptive degradation control method for an electric vehicle. Specifically, the electric vehicle of the present embodiment has at least two different levels of coasting feedback. The control method specifically comprises the following steps:
s10, collecting state data for indicating the state of the electric vehicle;
s20, judging whether the vehicle meets the first condition according to the state data;
s30, when the vehicle satisfies the first condition, determining whether the vehicle satisfies a second condition;
s40, under the condition that the vehicle meets the second condition, controlling the slide feedback level of the vehicle to be reduced by one level or kept at the lowest level;
wherein the first condition is that the vehicle is in a drivable state, the vehicle is in a D/R gear, a reference vehicle speed of the vehicle exceeds a predetermined value, the vehicle is in an unbraked state, and a required torque of the vehicle is negative (accelerator release); specifically, the above-described requirement is satisfied simultaneously by four conditions to satisfy the first condition. The driving-capable state of the specific vehicle is a state that the vehicle is electrified and started, but the vehicle is not driven. The reference speed in the embodiment is a longitudinal speed of the vehicle at the position of the mass center of the vehicle, and the range is approximately 0-255 km/h.
The second condition is any one selected from the group consisting of a time when the estimated ground adhesion coefficient is less than the preset value and the estimated ground adhesion coefficient is less than the preset value exceeding a first preset time, a wheel tendency to a lock state, or an ABS activation. Specifically, only one of the three conditions needs to be satisfied, and the second condition is satisfied.
In practice, the coasting feedback levels include a strong level, a medium level, a weak level, and a 0 level. When the vehicle itself is at the lowest level, i.e., level 0, no further downgrading is possible or necessary if the vehicle satisfies the second condition.
After the vehicle is judged to meet the first condition and the second condition, the vehicle performs degradation processing of the coasting feedback. In the second condition, when the ABS of the vehicle is activated, the sliding feedback is not directly exited but only degraded, so that the driver is not uncomfortable due to sudden change of the deceleration feeling of the vehicle during sliding, the road load is effectively utilized to feed back the power generation, and the method is better than the method for directly canceling the feedback. In addition, in the application, when the ABS is activated, the feedback torque is reduced step by step and waiting time is reserved, so that compared with the situation that the deceleration feeling is suddenly lost when the feedback torque is directly cancelled, the driving feeling is smoother.
In the embodiment, when the ABS is activated or the wheel is detected to be close to the locking limit, the feedback torque of a feedback level is decreased to determine whether the wheel locking is improved, and if the feedback torque is effective, the current feedback level is maintained, so that the situation that the wheel is locked again after the ABS exits is avoided. Compared with the prior art, the feedback is directly cancelled, and the ABS is not frequently activated.
FIG. 2 is a flowchart illustrating exemplary steps of a method for adaptive degradation control of coasting feedback for an electric vehicle according to an embodiment of the present invention; specifically, the estimated ground adhesion coefficient in the second condition is smaller than the preset value, which is the smaller value of the estimated ground adhesion coefficient between the first set value and the second set value, wherein the first set value x1 ═ T (g 1|/g) + s, and the second set value x2 ═ T |/(F × r g) + s; where g1 is the deceleration corresponding to the current feedback level, g is the gravity deceleration, s is the offset, T is the feedback torque request, F is the vehicle weight, and r is the tire radius.
The level of strong, medium and weak feedback corresponds to the deceleration reference of 0.15g/0.1g/0.05 g. The specific feedback level corresponds to the deceleration depending on the project requirements.
More specifically, the wheel locking is indicated when any one of the following fourth conditions is satisfied and the time for which the fourth condition is satisfied exceeds a second preset time, and the fourth condition includes:
the wheel speed is lower than the reference vehicle speed and the rate of change of the wheel speed is lower than a first threshold; or
The rate of change of wheel speed is below a second threshold, both the first threshold and the second threshold are negative and the first threshold > the second threshold.
The reference vehicle speed in the embodiment is a longitudinal vehicle speed of the vehicle mass center position, and the range is approximately 0-255 km/h. The first threshold value is-1000 km/h/s to-200 km/h/s and can be adjusted according to the actual vehicle condition. The second threshold value is-1000 km/h/s to-400 km/h/s.
More specifically, the ABS system of the vehicle is indicated to be activated when any one of the following fifth conditions is satisfied, wherein the fifth conditions include:
the ABS system is continuously activated for more than a third set time; or
The time during which the ABS system is activated accumulates to exceed the fourth set time.
Wherein the third set time is 0.1 s-10 s, depending on the actual vehicle. The fourth setting time is 0.1 s-10 s, depending on the actual vehicle.
The embodiment reasonably utilizes the road feedback and reduces the frequent feedback grade switching operation of the driver. Specifically, the low-attachment road surface is actively identified through low-attachment calculation, wheel locking prejudgment, ABS activation and the like to perform feedback degradation and maintain, the initial feedback level can be reasonably recovered under the working conditions of acceleration and the like, and manual operation of a driver is not needed. Compared with the prior art, the method directly cancels feedback, can reasonably utilize the road surface attachment to feed back for power generation, and improves pure electric endurance.
The fifth condition of this embodiment is that feedback degradation is triggered by the fact that the ABS activation accumulated time exceeds the limit value or the ABS continuous activation exceeds the limit value under the single-sliding feedback condition, and typical conditions such as continuous low-adhesion road surfaces (ice and snow wet road surfaces) and intermittent low-adhesion road surfaces (ice and snow chessboard road surfaces) are compatible.
FIG. 3 is a schematic flow chart diagram of a coasting feedback adaptive degradation control method for an electric vehicle according to another embodiment of the present invention; fig. 4 is a detailed flowchart of a coasting feedback adaptive degradation control method of an electric vehicle according to another embodiment of the present invention.
More specifically, the coasting feedback adaptive degradation control method of the electric vehicle may further include:
s50, determining whether a third condition is satisfied, and if any of the following third conditions is satisfied, restoring the coasting feedback level of the vehicle, the third condition including:
driver demand torque is positive (accelerator drive); or
The vehicle is in P/N gear.
More specifically, S60 outputs the feedback output level of the vehicle based on whether the vehicle satisfies the second condition, whether the third condition is satisfied, and the preselected feedback level;
s70 requesting the vehicle to output a corresponding feedback torque according to the feedback output level;
when the vehicle meets the third condition, the feedback output level of the vehicle is the initial feedback level, and the initial feedback level is the preselected feedback level. The state is defined as state 1.
When the vehicle does not satisfy the third condition but satisfies the second condition, the feedback output level of the vehicle is selected from the feedback levels which are degraded and are decreased one level on the basis of the feedback levels which are selected in advance, and the feedback output level is compared with the feedback levels which are selected in advance and is taken as a smaller level; defining this state as state 3. The process can timely respond to the operation of the driver for adjusting the feedback grade downwards, and the negative value of the feedback grade after degradation is avoided.
When the vehicle does not satisfy either the third condition or the second condition, the feedback output level of the vehicle is selected from the feedback output levels output by the vehicle that will maintain the degraded feedback level at a lesser level than the preselected feedback level; this state is defined as state 2. The process can respond to the operation of the driver for adjusting the feedback grade in time.
And repeating the judgment of the second condition and the third condition after the feedback output level is degraded.
When the feedback level output by the vehicle is degraded (i.e. the state 3 is established), if the vehicle does not satisfy the third condition but satisfies the second condition, the feedback output level output by the vehicle is decreased by one level based on the degraded feedback level and is output at a smaller level compared with the preselected feedback level.
When the feedback level outputted by the vehicle is degraded (i.e., the state 3 is established), if the vehicle does not satisfy the third condition and does not satisfy the second condition, the feedback output level outputted by the vehicle will maintain the feedback level that has been degraded to be outputted at a smaller level compared with the preselected feedback level.
The jump condition of the state machine between the state 1 and the state 3 is as follows:
condition for state 1 to jump to state 3: the second condition is satisfied.
Condition for state 2 to jump to state 3: the second condition is satisfied.
Condition for state 1 to jump to state 2: the second condition is not satisfied and the third condition is satisfied.
Condition for state 3 to jump to state 2: the second condition is not satisfied and the third condition is not satisfied.
Condition for state 3 to jump to state 1: the third condition is satisfied;
condition for state 2 to jump to state 1: the third condition is satisfied.
In the embodiment, in the process of vehicle sliding feedback, feedback grade is triggered to sequentially degrade through the detection of whether the road adhesion supports current feedback, wheel locking prediction, ABS activation (second condition) and other states, so that the feedback torque is reduced, and when a driver steps on an accelerator to drive (third condition), the feedback grade can be quickly recovered, so that the aims of maximally utilizing the road adhesion feedback and reducing frequent ABS activation in the whole running condition are fulfilled.
In addition, the sliding feedback adaptive degradation control method of the electric vehicle can judge whether the vehicle meets the first condition and the second condition again after the sliding grade of the vehicle is reduced by one grade, and when the vehicle meets the first condition and the second condition, the sliding feedback grade of the vehicle is continuously reduced by one grade; and repeating the process until the sliding feedback grade is 0 grade. The process shows that in the sliding feedback process, as long as the sliding feedback is not reduced to the level of 0, the detection and judgment process is continued all the time, and the sliding feedback level is adjusted in real time according to the specific working condition and state of the vehicle, so that the driving smoothness is ensured, and the pure electric endurance is improved.
FIG. 5 is a schematic block diagram of a coasting feedback adaptive degradation control system of an electric vehicle according to one embodiment of the present invention; as an embodiment of the present invention, the present embodiment further provides a coasting feedback adaptive degradation control system 100 for an electric vehicle, wherein the electric vehicle has at least two different coasting feedback levels. The system 100 may include an acquisition module 10, a first determination module 20, a second determination module 30, and a control module 40. The acquisition module 10 is used for acquiring status data of the vehicle. The first determining module 20 is configured to determine whether the vehicle satisfies a first condition according to the status data. The second determining module 30 is configured to determine whether the vehicle satisfies the second condition if the vehicle satisfies the first condition. The control module 40 is configured to control the coasting feedback level of the vehicle to decrease by one step or to maintain a minimum level if the vehicle satisfies the second condition. The first condition is that the vehicle is in a driving state, the vehicle is in a D/R gear, the reference vehicle speed of the vehicle exceeds a preset value, the vehicle is in an unbraked state and the vehicle is in a feedback state. Specifically, the above-described requirement is satisfied simultaneously by four conditions to satisfy the first condition. The particular vehicle is in a drivable state in which the vehicle is electrically started, but the vehicle is not being driven. The reference speed in the embodiment is a longitudinal speed of the vehicle at the position of the mass center of the vehicle, and the range is approximately 0-255 km/h.
The second condition is one selected from the group consisting of a time at which the estimated ground adhesion coefficient is less than a preset value and the estimated ground adhesion coefficient is less than the preset value exceeding a first preset time, a wheel tendency to a locked state, or an ABS activation. Specifically, only one of the three conditions needs to be satisfied, and the second condition is satisfied.
Wherein, the preset value is a certain vehicle speed between 3-10 km/h, and can be adjusted according to the actual vehicle condition. The first preset time is 0.05 s-10 s, depending on the actual vehicle.
In the actual process, the coasting feedback levels include a strong level, a medium level, a weak level, and a 0 level. When the vehicle itself is at the lowest level, i.e., level 0, no further downgrading is possible or necessary if the vehicle satisfies the second condition.
FIG. 6 is a schematic block diagram of an acquisition module and a data monitoring and calculation module of a coasting feedback adaptive degradation control system for an electric vehicle according to an embodiment of the present invention; specifically, the acquisition module may acquire data detected or calculated by a vehicle reference vehicle speed calculation unit (ECU1), a road surface adhesion coefficient calculation unit (ECU2), an ABS (anti-lock brake system) control unit (ECU3), a gear selection module (MCU1), a power-up and power-down management module (MCU2), a torque demand calculation module (MCU3), a wheel speed Sensor (Sensor1), a brake pedal Sensor (Sensor2), a human-machine interaction unit (HMI), a Timer (Timer1), and a torque execution unit (Actuator 1).
Specifically, the vehicle reference speed calculation unit estimates the speed of the center of mass of the entire vehicle from the wheel speed, the longitudinal acceleration, and the like to represent the actual longitudinal speed of the vehicle. And the road adhesion coefficient calculation unit is used for estimating the road adhesion coefficient according to the conditions of vehicle slip, yaw instability and the like to represent the driving force or braking force coefficient which can be effectively utilized by the current road.
The ABS (anti-lock brake system) control unit is used for detecting the situation that the wheels are locked due to low adhesion on the ground or over braking, actively clamping and releasing the braking force to improve the braking performance, and providing an ABS state signal to indicate whether the ABS is activated or not.
The gear selection module switches the moving direction of the vehicle through gear shifting operation of the driver, and provides PRND gear signals to represent the intention of the driver that the vehicle is expected to move forwards, backwards, idle and slide, park and the like.
And the power-on and power-off management module is used for managing high-voltage and low-voltage power supply, key electric devices and power system work, anti-theft system authentication and the like, and providing a vehicle travelable state signal to represent that the system can normally support the vehicle to travel.
The torque demand calculation module calculates a torque request for driving/feedback of the power system according to various factors such as accelerator opening, vehicle speed, driving mode, power system capacity, actual feedback level and the like, and provides a torque demand signal and a driving/feedback torque request signal for a torque execution unit such as a motor and the like to output torque.
Four wheel speed sensors monitor the wheel speeds of the left front wheel, the right front wheel, the left rear wheel and the right rear wheel in real time and provide other modules.
The brake pedal sensor monitors the action of the driver for pressing the brake pedal in real time, and provides a brake pedal pressing state signal to represent whether the driver presses the brake pedal.
The man-machine interaction unit can adjust the feedback strength of the power system by selecting strong, medium and weak feedback levels for a driver, provides a feedback level signal RgnLvlSelected (namely a preselected feedback level) selected by the driver, and receives an actual feedback level RgnLvActIndcn to prompt the user.
The timer is used for carrying out duration timing or accumulated triggering time timing within a period of time when certain conditions are triggered, and the timer can be reset when certain conditions are met.
The torque execution unit is a device, such as a motor, which outputs torque after receiving a driving/feedback torque request.
According to the method, after the vehicle is judged to meet the first condition and the second condition, the vehicle performs degradation processing of sliding feedback. In the second condition, the coast feedback is not directly exited, but is merely degraded, when the ABS of the vehicle is activated, which is preferable to the prior art where the feedback is directly cancelled. In addition, in the application, when the ABS is activated, the feedback torque is reduced step by step and waiting time is reserved, so that compared with the situation that the deceleration feeling is suddenly lost when the feedback torque is directly cancelled, the driving feeling is smoother.
When the ABS is activated or the wheel is detected to be close to the locking limit, the torque of a feedback level is reduced to judge whether the wheel locking is improved or not, if the torque is effective, the current feedback level is maintained, and the situation that the wheel is locked again after the ABS is withdrawn and the ABS is triggered due to feedback recovery is avoided. Compared with the prior art, the feedback is directly cancelled, and the ABS is not frequently activated.
Fig. 7 is a detailed flowchart of the coasting feedback adaptive degradation control system of an electric vehicle according to another embodiment of the present invention.
Specifically, the coasting feedback adaptive degradation control system of the electric vehicle of the embodiment may further include a feedback level recovery module 50, where the feedback level recovery module 50 is configured to determine whether any of the following third conditions is met, and if so, recover the coasting feedback level of the vehicle, where the third conditions include:
the driver demand torque is positive; or
The vehicle is in P/N gear.
The third condition is mainly the required torque of the driver calculated by the gear selection module and the torque demand calculation module of the vehicle.
The third condition is primarily to be able to maintain the level of coasting feedback or return it to the original coasting feedback level.
Specifically, the coasting feedback adaptive degradation control system of the electric vehicle of the present embodiment may further include a feedback level output module 60 and a torque request module 70. The feedback level output module 60 is configured to output the feedback output level of the vehicle according to whether the vehicle satisfies the second condition, whether the vehicle satisfies the third condition, and the preselected feedback level. The torque request module 70 is configured to request the vehicle to output a feedback torque corresponding to the feedback output level. When the vehicle meets the third condition, the feedback output level of the vehicle is an initial feedback level, and the initial feedback level is a preselected feedback level. The state is defined as state 1.
When the vehicle does not satisfy either the third condition or the second condition, the feedback output level of the vehicle is selected from the feedback output levels output by the vehicle that will maintain the degraded feedback level at a lesser level than the preselected feedback level. The process can respond to the operation of the driver for adjusting the feedback grade in time. This state is defined as state 2.
When the vehicle does not satisfy the third condition but satisfies the second condition, the feedback output level of the vehicle is selected to be lower than a predetermined feedback level based on the feedback level that has been degraded. The process can timely respond to the operation of the driver for adjusting the feedback grade downwards, and the negative value of the feedback grade after degradation is avoided. This state is defined as state 3.
And repeating the judgment of the second condition and the third condition after the feedback output level is degraded.
Specifically, after the feedback level of the vehicle output is degraded (i.e., state 3 is established), if the vehicle does not satisfy the third condition but satisfies the second condition, the feedback level of the vehicle output is decreased by one level based on the degraded feedback level and is output at a smaller level than the preselected feedback level.
When the feedback level output by the vehicle is degraded (i.e. the state 3 is established), if the vehicle does not satisfy the third condition and does not satisfy the second condition, the feedback level output by the vehicle maintains the degraded feedback level to be output at a smaller level compared with the preselected feedback level.
The jump condition of the state machine between the state 1 and the state 3 is as follows:
condition for state 1 to jump to state 3: the second condition is satisfied.
Condition for state 2 to jump to state 3: the second condition is satisfied.
Condition for state 1 to jump to state 2: the second condition is not satisfied and the third condition is satisfied.
Condition for state 3 to jump to state 2: the second condition is not satisfied and the third condition is not satisfied.
Condition for state 3 to jump to state 1: the third condition is satisfied.
Condition for state 2 to jump to state 1: the third condition is satisfied.
In the embodiment, in the vehicle sliding feedback process, feedback grade sequential degradation processing is triggered by detecting whether the road adhesion supports current feedback, wheel locking prediction, ABS activation (second condition) and other states, so that the feedback torque is reduced, and the feedback grade can be quickly recovered when a driver steps on an accelerator to drive (third condition), so that the aims of maximally utilizing the road adhesion feedback and reducing the frequent activation of the ABS in the whole running condition are fulfilled.
Thus, it should be appreciated by those skilled in the art that while a number of exemplary embodiments of the invention have been illustrated and described in detail herein, many other variations or modifications consistent with the principles of the invention may be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Accordingly, the scope of the invention should be understood and interpreted to cover all such other variations or modifications.
Claims (10)
1. A coasting feedback adaptive degradation control method for an electric vehicle, the electric vehicle having at least two different coasting feedback levels, the coasting feedback adaptive degradation control method for the electric vehicle comprising:
collecting state data representing the state of the electric vehicle;
judging whether the vehicle meets a first condition or not according to the state data;
under the condition that the vehicle meets the first condition, judging whether the vehicle meets a second condition or not;
controlling a coasting feedback level of the vehicle to be reduced by one level or maintained at a minimum level if the vehicle satisfies the second condition;
wherein the first condition is that the vehicle is in a drivable state, the vehicle is in a D/R gear, a reference vehicle speed of the vehicle exceeds a predetermined value, the vehicle is in an unbraked state, and the vehicle is in a regenerative state;
the second condition is any one selected from the group consisting of a time at which the estimated ground adhesion coefficient is less than a preset value and the estimated ground adhesion coefficient is less than the preset value exceeding a first preset time, a wheel tendency to a locked state, or an ABS activation.
2. The coasting feedback adaptive degradation control method of an electric vehicle according to claim 1,
further comprising:
judging whether a third condition is met, and if the third condition is met, recovering the sliding feedback grade of the vehicle, wherein the third condition comprises any one of the following conditions:
the driver demand torque is positive; or
The vehicle is in P/N gear.
3. The coasting feedback adaptive degradation control method of an electric vehicle according to claim 2,
after determining whether the third condition is satisfied, the method further comprises:
outputting a feedback output grade of the vehicle according to whether the vehicle meets the second condition, whether the vehicle meets the third condition and a preselected feedback grade, wherein the feedback output grade is the feedback grade actually output by the vehicle;
requesting the vehicle to output corresponding feedback torque according to the feedback output grade;
when the vehicle meets the third condition, the feedback output level of the vehicle is an initial feedback level, and the initial feedback level is a preselected feedback level;
when the vehicle does not satisfy the third condition but satisfies the second condition, the feedback output level of the vehicle is selected to be lower than the feedback level which is degraded and is compared with the preselected feedback level to take a smaller level;
when the vehicle does not satisfy either the third condition or the second condition, the feedback output level of the vehicle is selected from the lower of the feedback output levels output by the vehicle that will maintain the degraded feedback level compared to the preselected feedback level;
and repeating the judgment of the second condition and the third condition after the feedback output level is degraded.
4. The coasting feedback adaptive degradation control method of an electric vehicle according to claim 2 or 3,
when the sliding grade of the vehicle is reduced by one grade downwards, whether the vehicle meets the first condition and the second condition is judged again, and when the vehicle meets the first condition and the second condition is judged, the sliding feedback grade of the vehicle is continuously reduced by one grade downwards;
and repeating the process until the sliding feedback grade is 0 grade.
5. The coasting feedback adaptive degradation control method of an electric vehicle according to claim 1,
the estimated ground adhesion coefficient is smaller than a preset value, which is the smaller value of the estimated ground adhesion coefficient between a first set value and a second set value, wherein the first set value x1 is (| g1|/g) + s, and the second set value x2 is | T |/(F × g) + s;
where g1 is the deceleration corresponding to the current feedback level, g is the gravity deceleration, s is the offset, T is the feedback torque request, F is the vehicle weight, and r is the tire radius.
6. The coasting feedback adaptive degradation control method of an electric vehicle according to claim 1,
indicating that the wheel is locked when the following condition is satisfied and the time for which the condition is satisfied exceeds a second preset time:
the wheel speed is lower than the reference vehicle speed and the rate of change of the wheel speed is lower than a first threshold; or
The rate of change of wheel speed is below a second threshold, the first threshold and the second threshold are both negative and the first threshold > the second threshold.
7. The coasting feedback adaptive degradation control method of an electric vehicle according to claim 1,
when any one of the following conditions is met, it indicates that the ABS system of the vehicle is activated:
the ABS system is continuously activated for more than a third set time;
and the time of the ABS system activation exceeds the fourth set time in an accumulated mode.
8. A coasting feedback adaptive degradation control system for an electric vehicle having at least two different levels of coasting feedback, comprising:
the acquisition module is used for acquiring state data which represents the state of the electric vehicle;
the first judgment module is used for judging whether the vehicle meets a first condition or not according to the state data;
the second judgment module is used for judging whether the vehicle meets a second condition or not under the condition that the vehicle meets the first condition; and
the control module is used for controlling the coasting feedback level of the vehicle to be reduced by one level or kept at the lowest level under the condition that the vehicle meets the second condition;
wherein the first condition is that the vehicle is in a drivable state, the vehicle is in a D/R gear, a reference vehicle speed of the vehicle exceeds a predetermined value, the vehicle is in an unbraked state, and a required torque of the vehicle is negative;
the second condition is any one selected from the group consisting of a time at which the estimated ground adhesion coefficient is less than a preset value and the estimated ground adhesion coefficient is less than the preset value exceeding a first preset time, a wheel tendency to a locked state, or an ABS activation.
9. The coasting feedback adaptive degradation control system of an electric vehicle of claim 8,
the vehicle taxi feedback system further comprises a feedback grade reply module, wherein the grade reply module is used for judging whether a third condition is met, if the third condition is met, the taxi feedback grade of the vehicle is restored, and the third condition comprises any one of the following conditions:
the driver demand torque is positive; or
The vehicle is in P/N gear.
10. The coasting feedback adaptive degradation control system of an electric vehicle of claim 9,
further comprising:
the feedback grade output module is used for outputting the feedback output grade of the vehicle according to whether the vehicle meets the second condition, whether the vehicle meets the third condition and the preselected feedback grade, wherein the feedback output grade is the feedback grade actually output by the vehicle; and
the torque request module is used for requesting the vehicle to output corresponding feedback torque according to the feedback output grade;
when the vehicle meets the third condition, the feedback output level of the vehicle is an initial feedback level, and the initial feedback level is a preselected feedback level;
the feedback output level of the vehicle is selected from the feedback levels that have degraded by one step and the feedback levels that have been selected in advance and compared to take a smaller level; when the vehicle does not satisfy either the third condition or the second condition, the feedback output level of the vehicle is selected from the lower of the feedback output levels output by the vehicle that will maintain the degraded feedback level compared to the preselected feedback level;
and repeating the judgment of the second condition and the third condition after the feedback output level is degraded.
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| CN113022320B (en) * | 2021-04-30 | 2022-09-16 | 宝能(广州)汽车研究院有限公司 | Energy recovery control method, device, equipment and storage medium |
| CN113212172A (en) * | 2021-05-10 | 2021-08-06 | 宝能(广州)汽车研究院有限公司 | Energy feedback control method and device for electric automobile, medium and electronic equipment |
| CN113370802A (en) * | 2021-07-31 | 2021-09-10 | 重庆长安新能源汽车科技有限公司 | Recovered torque control method and system and vehicle |
| CN113586266A (en) * | 2021-08-31 | 2021-11-02 | 重庆长安汽车股份有限公司 | Engine rotating speed control method and system of automatic transmission type |
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| CN104494599B (en) * | 2014-01-30 | 2015-11-25 | 比亚迪股份有限公司 | Vehicle and slide back-feed control method |
| JP6354778B2 (en) * | 2016-03-24 | 2018-07-11 | トヨタ自動車株式会社 | Control device for vehicle power transmission device |
| CN108515960B (en) * | 2018-03-27 | 2020-04-21 | 吉利汽车研究院（宁波）有限公司 | Sliding energy recovery method, device and system |
| WO2019213655A1 (en) * | 2018-05-04 | 2019-11-07 | Nimbus Engineering Inc. | Regenerative braking using phosphorescence |
| CN111284491B (en) * | 2018-12-06 | 2022-12-30 | 博世汽车部件(苏州)有限公司 | Adjustment method and adjustment device for coasting recovery torque and vehicle |
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