CN112406853B - Yaw and roll stability integrated control method for wheel hub motor-driven off-road vehicle - Google Patents
Yaw and roll stability integrated control method for wheel hub motor-driven off-road vehicle Download PDFInfo
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Abstract
The invention discloses a yaw and roll stability integrated control method for a wheel hub motor-driven off-road vehicle, which comprises the steps of obtaining vehicle operation parameters, obtaining a transverse load transfer rate and a transverse motion balance equation at the current moment, and then obtaining a predicted transverse load transfer rate at the next moment; determining a yaw stability working condition according to the yaw angular velocity and the centroid slip angle; and determining a control mode of the yaw and roll integrated control system according to the predicted lateral load transfer rate and the yaw stability working condition. When the absolute value of the predicted transverse load transfer rate is smaller than a safety threshold, controlling the yaw stability as a primary target; when the absolute value of the predicted lateral load transfer rate is greater than or equal to the safety threshold, roll stability control is taken as a primary target, and yaw stability control is taken as a secondary target. The invention realizes the coordinated optimization of the roll stability control system and the yaw stability control system, eliminates the conflict when the two subsystems are controlled independently, and carries out the coordinated control to ensure the safety of the vehicle.
Description
Technical Field
The invention relates to the technical field of automobile stability control, in particular to an integrated control method for yaw and roll stability of a cross-country vehicle driven by a hub motor.
Background
In the Yaw stability Control of the vehicle, when the lateral acceleration of the vehicle is too large or the road surface adhesion condition is poor, the sideslip phenomenon is easy to occur, the vehicle cannot run according to the track expected by a driver, the lateral force of the tire is saturated at the moment, the longitudinal force of the tire has larger margin than the lateral force, an additional Yaw moment can be applied to the vehicle through the longitudinal force adjustment of the tire, the stability of the vehicle is ensured, and under the limit working condition, Direct Yaw moment Control (DYC) has a good Control effect. The DYC of the conventional vehicle is realized by means of differential braking, influences the longitudinal speed of the vehicle and generates interference to a driver.
A distributed electric vehicle yaw stability control method comprises the steps of determining a centroid slip angle-centroid slip angular velocity phase plane diagram corresponding to a road where a vehicle is located according to a road adhesion coefficient; and determining a maximum stable region and a minimum stable region of the centroid side angle-centroid side angular velocity phase plane diagram by adopting a bilinear method, wherein the boundary of the maximum stable region is a maximum boundary, and the boundary of the minimum stable region is a minimum boundary. And determining the position of a phase track point of the vehicle in the current state in the centroid slip angle-centroid slip angular velocity phase plane diagram, determining a centroid slip angle weight coefficient according to the current position, and further calculating an expected additional yaw moment according to the state data, the centroid slip angle weight coefficient, the expected yaw angular acceleration and the expected centroid slip angular velocity to realize yaw stability control.
The maximum stable region and the minimum stable region of the centroid side deflection angle-centroid side deflection angle speed phase plane diagram are determined by a bilinear method, and then the centroid side deflection angle weight coefficient is determined to conduct roll stability control judgment. The weight coefficient is selected singly, because the centroid slip angle is only an important index in stability analysis and control, all conditions of vehicle stability cannot be described visually, and the phase plane stable area can be influenced by factors such as steering wheel rotation angle, vehicle speed, control system action, road adhesion coefficient and the like from people, vehicles, control systems and environment, so that the representation of the vehicle stability under different working conditions by the centroid slip angle phase plane cannot be reflected. Meanwhile, under different forms of working conditions, the maximum stable area and the minimum stable area of the phase plane graph need to be determined, the control responsiveness is poor, the area division is complex, and the determination of the relative position of the vehicle phase track point through the central point of the area is simpler.
The integrated chassis control system is controlled by adopting a layered cooperative control structure and is specifically divided into three layers, wherein the upper layer comprises a driver control layer and a motion control layer, and the middle layer comprises a tire force distribution layer and a lower actuator control layer. Measurable quantities such as torque and rotating speed information of four wheels are utilized, a control instruction is given through a driver control layer, and then a model predictive control algorithm is adopted to design a motion controller to obtain the vertical and horizontal resultant force and resultant torque expected by the vehicle. The middle layer mainly solves the distribution problem of resultant force and resultant moment, and comprises the formulation of a target function and the selection of constraint conditions. The lower layer converts the distributed tire force into wheel rotation angle, motor drive and active suspension force which can be identified by an actuator, so that the optimal tire force of the vehicle is obtained, and the maneuverability, the stability and the comfort of the vehicle are ensured.
The final goal of the integrated control system is to realize the coordination and optimization among the subsystems, fully exert the functions of the subsystems and eliminate the conflicts among the subsystems. In the technology, the middle-level strategy development is only to design the optimal tire force for distribution, control systems under different working conditions are not coordinately selected, and different control modes are required under different threshold judgment conditions. The chassis active control technology is designed only aiming at a single function and a chassis subsystem, but in the running process of a vehicle, the chassis subsystems are not completely independent but mutually influenced, and when multiple control systems exist simultaneously, if each control system is independent control without considering the coupling relation of multiple systems, the advantage of multi-system combined control cannot be fully played, so that the problem of function conflict exists even under certain conditions.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide an integrated control method for yaw and roll stability of a cross-country vehicle driven by a hub motor.
In order to achieve the purpose, the invention provides an integrated control method for yaw and roll stability of a wheel hub motor driven off-road vehicle, which is characterized by comprising the following steps: obtaining vehicle operation parameters, obtaining a transverse load transfer rate and a transverse motion balance equation at the current moment, and then obtaining a predicted transverse load transfer rate at the next moment; determining a yaw stability working condition according to the yaw angular velocity and the centroid slip angle; and determining a control mode of the yaw and roll integrated control system according to the predicted lateral load transfer rate and the yaw stability working condition.
Further, when the absolute value of the predicted lateral load transfer rate is smaller than the safety threshold, the yaw stability is controlled first.
Further, when the absolute value of the predicted lateral load transfer rate is greater than or equal to the safety threshold, the roll stability is controlled first, and then the yaw stability is controlled.
Further, when the absolute value of the yaw angular velocity is smaller than the threshold value of the yaw angular velocity and the absolute value of the centroid slip angle is smaller than the threshold value of the centroid slip angle, the working condition of the yaw stability is a safe working condition, and the control action is not executed.
Further, when the absolute value of the yaw angular velocity is smaller than the yaw angular velocity threshold or the absolute value of the centroid slip angle is smaller than the centroid slip angle threshold, the yaw stability working condition is an unstable working condition, the steering maneuverability optimization mode is entered, and only the yaw stability control is carried out.
Further, when the absolute value of the yaw rate is greater than or equal to the yaw rate threshold value and the absolute value of the centroid slip angle is greater than or equal to the centroid slip angle threshold value, the yaw stability working condition is a limit working condition, the yaw stability control mode is entered, the yaw stability is controlled firstly, and then the roll stability is controlled.
Further, when the absolute value of the yaw angular velocity is smaller than the yaw angular velocity threshold or the absolute value of the centroid slip angle is smaller than the centroid slip angle threshold, the yaw stability working condition is an unstable working condition, the anti-roll control mode is entered, the roll stability is controlled firstly, and then the yaw stability is controlled.
Further, when the absolute value of the yaw rate is greater than or equal to the yaw rate threshold value and the absolute value of the centroid slip angle is greater than or equal to the centroid slip angle threshold value, the yaw stability condition is a limit condition, the extreme stability control mode is entered, the roll stability is controlled firstly, then the yaw stability is controlled, and the direct yaw moment is limited.
Further, the roll stability control method comprises the steps of determining a centroid target height according to a vehicle speed and a predicted transverse load transfer rate, obtaining a target roll angle through transverse acceleration, finally obtaining target heights of all suspensions according to the centroid target height, the target roll angle and a target pitch angle, and adjusting an actual roll angle to reach the target roll angle by controlling the target heights of all the suspensions.
Further, when the vehicle speed is lower than the set vehicle speed, the safety threshold value for predicting the transverse load transfer rate is a first safety threshold value, and when the absolute value of the transverse load transfer rate is lower than the first safety threshold value, the centroid target height is a first centroid height; and when the absolute value of the predicted transverse load transfer rate is greater than or equal to the first safety threshold, the centroid target height is a third centroid height.
Further, when the vehicle speed is greater than or equal to the set vehicle speed, the safety threshold for predicting the transverse load transfer rate is a second safety threshold, and when the absolute value of the predicted transverse load transfer rate is smaller than the second safety threshold, the centroid target height is a second centroid height; and when the absolute value of the predicted transverse load transfer rate is greater than or equal to the second safety threshold, the centroid target height is a third centroid height.
Further, the first safety threshold is greater than a second safety threshold.
Further, the first centroid height, the second centroid height and the third centroid height decrease in sequence.
Further, the predicted transverse load transfer rate PLTR is
Wherein LTR is a lateral load transfer rate, t0Is the current time, at is the calculation period.
Further, the lateral load transfer rate LTR is
Wherein h isgIs the vehicle center of mass height, twIs the track width of ayIs the vehicle lateral acceleration, g is the gravitational acceleration,
is the roll angle.
Further, the lateral motion balance equation is
Wherein beta is the centroid slip angle,
m is the vehicle mass, a is the distance from the center of mass to the front axle, b is the distance from the center of mass to the rear axle, kfIs the tire sidewall deflection stiffness, k, of the front wheelrIs the tire sidewall deflection stiffness, V, of the rear wheelxIs the longitudinal vehicle speed, γ is the yaw rate, and δ is the front wheel angle.
Further, the target roll angle
Is composed of
Wherein, ayIs the lateral acceleration of the vehicle, c1、c2、c3、c4Are all constant, and c1＝-c2，c3＝-c4。
Further, the yaw stability control method includes controlling the yaw rate and the centroid slip angle by controlling the direct yaw moment.
Further, the method for determining the yaw stability condition comprises the steps of constructing a two-dimensional phase plane coordinate system according to the yaw velocity and the centroid side offset angle, determining a parameter area of each yaw stability condition in the coordinate system and an activation function of each yaw stability condition, and when the activation functions meet the activation conditions of the yaw stability condition, locating the yaw stability condition.
Further, when yawingWhen the stability working condition is a safe working condition, the activation function h of the safe working condition3(X) is
h3(X)＝H9(X)。
When the yaw stability working condition is an unstable working condition, the activation function h of the unstable working condition2(X) is
When the yaw stability working condition is the limit working condition, the activation function h of the limit working condition1(X) is
Wherein,
wherein X ═ β γ]TThe number L of the center points of the parameter domain of the working condition of the yaw stability is 9 and C is the coordinate of the current momentjThe coordinates of the central point of the jth parameter domain; σ is a shape parameter, representing the distance of a center point of the parameter domain from the boundary of the parameter domain.
Further, an activation function h when in safe operating mode3(X) is less than the activation function h3Threshold value h of (X)3(X)thIn the meantime, the yaw stability condition is a safe condition.
Further, an activation function h when in safe operating mode3(X) is greater than or equal to the activation function h3Threshold value h of (X)3(X)thTime and unsteady regime of the activation function h2(X) is less than the activation function h2Threshold value h of (X)2(X)thIn time, the yaw stability condition is an unstable condition.
Further, the activation function h under safe conditions3(X) is greater than or equal to the activation function h3Threshold value h of (X)3(X)thTime and unsteady regime of the activation function h2(X) is greater than or equal to the activation function h2Threshold value h of (X)2(X)thAnd in time, the working condition of yaw stability is a limit working condition.
The invention has the beneficial effects that: and determining five control modes of the yaw and roll integrated control system according to the predicted transverse load transfer rate and the yaw stability working condition, firstly controlling the yaw stability by controlling the direct yaw moment when only the yaw stability is insufficient, and firstly controlling the roll stability by controlling the target roll angle and then secondarily controlling the yaw stability when only the roll stability is insufficient. The coordinated optimization of the roll stability control system and the yaw stability control system is realized, the conflict between the two subsystems in independent control is eliminated, and the coordinated control is carried out to ensure the safety of the vehicle.
Drawings
Fig. 1 is a flowchart of the yaw and roll stability integrated control method of the present invention.
Fig. 2 is a flow chart of a control method of the roll stability control system of the present invention.
FIG. 3 is a flow chart of the control method of the yaw stability control system of the present invention
FIG. 4 is a schematic diagram of a two-dimensional phase plane coordinate system according to the present invention.
Detailed Description
The following detailed description is provided to further explain the claimed embodiments of the present invention in order to make it clear for those skilled in the art to understand the claims. The scope of the invention is not limited to the following specific examples. It is intended that the scope of the invention be determined by those skilled in the art from the following detailed description, which includes claims that are directed to this invention.
An integrated control system for yaw and roll stability of an off-road vehicle driven by an in-wheel motor comprises a roll stability control system and a yaw stability control system, wherein the roll stability control system and the yaw stability control system can be independently controlled when not controlled by the integrated control system for yaw and roll stability.
As shown in fig. 2, the roll stability control system independent control process is:
firstly, obtaining each running parameter of the vehicle to obtain a transverse load transfer rate and a transverse motion balance equation.
In this embodiment, the lateral load transfer ratio LTR is
Wherein h isgIs the vehicle center of mass height, twIs the track width of ayIs the vehicle lateral acceleration, g is the gravitational acceleration,
is a roll angle, which is the angle between the vertical central axis of the vehicle and the ground.
In this embodiment, the equation for the balance of lateral motion is
Wherein,
beta is a centroid slip angle, is an included angle between the centroid speed direction and the locomotive direction, m is the whole vehicle mass, a is the distance from the centroid to the front axle, b is the distance from the centroid to the rear axle, and kfIs the tire sidewall deflection stiffness, k, of the front wheelrIs the tire sidewall deflection stiffness, V, of the rear wheelxIs the longitudinal vehicle speed, γ is the yaw rate, and δ is the front wheel angle.
Because the transverse load transfer rate can only reflect the state quantity of the transverse load transfer rate at the current moment and cannot reflect the dynamic change of the transverse load transfer rate, a predicted transverse load transfer rate is defined, the transverse load transfer rate at the next moment can be predicted according to the current transverse load transfer rate, and the predicted transverse load transfer rate PLTR is
Wherein LTR is a lateral load transfer rate, t0Is the current time, at is the calculation period.
Substituting the transverse motion balance equation into the transverse load transfer rate expression to finally obtain the predicted transverse load transfer rate PLTR of
In the embodiment, when the vehicle speed is less than 40Km/h, the safety threshold for predicting the transverse load transfer rate is 0.8, and when the absolute value of the predicted transverse load transfer rate is less than 0.8, the vehicle is not in the risk of rolling at the moment, and the target height of the center of mass is maintained at 1060mm of the normal height; when the absolute value of the predicted lateral load transfer rate is greater than or equal to 0.8, indicating that the vehicle is at risk of rolling at the moment, the target height of the center of mass is reduced to 660mm, and the risk of rolling of the vehicle can be effectively reduced.
When the vehicle speed is greater than or equal to 40Km/h, the risk of the vehicle rolling is increased, the safety threshold value for predicting the transverse load transfer rate is reduced to be 0.7, when the absolute value of the transverse load transfer rate is less than 0.7, the vehicle is indicated to have no risk of rolling at the moment, and the target height of the center of mass is 860 mm; when the absolute value of the predicted lateral load transfer rate is greater than or equal to 0.7, indicating that the vehicle is at risk of rolling at that time, the centroid target height is also reduced to 660 mm.
In this embodiment, the target roll angle is calculated according to the lateral acceleration of the vehicle
Is composed of
Wherein, ayIs the lateral acceleration of the vehicle, c1、c2、c3、c4Are all constant, and c1＝-c2，c3＝-c4. The target roll angle obtained by the method satisfies the following conditions: when lateral acceleration is less, the roll angle can be as little as possible, guarantees the travelling comfort, and when lateral acceleration crescent, the roll angle can suitably increase, guarantees that the driver obtains better feedback to when lateral acceleration reaches certain degree, the roll angle is restricted, prevents to take place danger.
And finally, the control target of the roll stability is realized by controlling the roll angle to reach a target roll angle, the target height of each suspension is obtained according to the calculated centroid target height, the target roll angle and the target pitch angle, and the actual roll angle is adjusted to reach the target roll angle by controlling the target height of each suspension.
As shown in fig. 3 to 4, the independent control process of the yaw stability control system is as follows:
firstly, a beta-gamma two-dimensional phase plane coordinate system is constructed by taking the yaw velocity as an abscissa and taking the centroid side slip angle as an ordinate, a parameter domain of each yaw stability working condition in the coordinate system and an activation function of each yaw stability working condition are determined, and when the activation functions meet the activation conditions of the yaw stability working conditions, the yaw stability working conditions are located.
In this embodiment, when the absolute value of the yaw angular velocity is smaller than the yaw angular velocity threshold and the absolute value of the centroid slip angle is smaller than the centroid slip angle threshold, the parameter domain is located in the region 1, and the yaw stability condition is a safe condition. When the absolute value of the yaw angular velocity is smaller than the yaw angular velocity threshold or the absolute value of the centroid slip angle is smaller than the centroid slip angle threshold, the parameter domain is located in the region 2, and the yaw stability working condition is an unstable working condition. When the absolute value of the yaw angular velocity is larger than or equal to the yaw angular velocity threshold and the absolute value of the centroid slip angle is larger than or equal to the centroid slip angle threshold, the parameter domain is located in the region 3, and the yaw stability working condition is the limit working condition. Because the yaw velocity threshold value and the centroid slip angle threshold value under different working conditions are uncertain, the judgment is difficult, and the yaw stability working condition can be judged by constructing an activation function of each parameter domain.
In this embodiment, when the yaw stability condition is the safe condition, the activation function h of the safe condition3(X) is
h3(X)＝H9(X)。
When the yaw stability working condition is an unstable working condition, the activation function h of the unstable working condition2(X) is
When the yaw stability working condition is the limit working condition, the activation function h of the limit working condition1(X) is
Wherein,
wherein X ═ β γ]TThe number L of the center points of the parameter domain of the working condition of the yaw stability is 9 and C is the coordinate of the current momentjThe coordinates of the central point of the jth parameter domain; σ is a shape parameter, representing the distance of a center point of the parameter domain from the boundary of the parameter domain. The smaller sigma, ηjThe smaller (X) the larger the activation function, the faster the activation function can be determined and compared to the threshold of the activation function, the faster the control; the smaller σ, the smoother the control process. The activation function can clearly represent the vehicle control state, and meanwhile, the control strategy can be controlled quickly or smoothly by controlling sigma, so that the stability is improved, and the control strategy is prevented from being frequently intervened or quitted.
The coordinate of the center point of the area 3 is Ch1The coordinate of the center point of the area 2 is Ch2The coordinate of the center point of the area 1 is Ch3。
In this embodiment, the activation function h under safe conditions3(X) is less than activation function h3And (X) when the threshold value is 0.126, the yaw stability working condition is a safe working condition, and the yaw velocity and the mass center slip angle do not need to be adjusted.
In this embodiment, the activation function h under safe conditions3(X) is greater than or equal to the activation function h3(X) threshold of 0.126, and an activation function h of an unstable condition2(X) is less than the activation function h2When the threshold value of (X) is 0.415, the yaw stability condition is an unstable condition, and at this time, the control target of the yaw rate is satisfied first.
In this embodiment, the activation function h under safe conditions3(X) is greater than or equal to the activation function h3Threshold value of 0.126 for (X), and activation function h for unstable conditions2(X) is greater than or equal to the activation function h2When the threshold value of (X) is 0.415, the yaw stability condition is the limit condition, and at this time, the control target of the centroid slip angle is satisfied first.
In the embodiment, the yaw stability control method is to control the yaw rate and the mass center slip angle by independently adjusting the driving torque of each hub motor.
If the roll stability control system and the yaw stability control system are controlled independently, and both systems need to be controlled simultaneously under certain working conditions, such as when the yaw stability is in an unstable state and the roll stability is in danger, the priority of the control process cannot be determined, and the conflict between the two systems is easily caused, as shown in fig. 1, the yaw and roll stability integrated control method for the wheel hub motor-driven off-road vehicle determines the control mode of the yaw and roll integrated control system according to the predicted transverse load transfer rate and the yaw stability working condition, performs coordinated optimization on the control targets of the two systems, eliminates the conflict when the two subsystems are controlled independently, and performs coordinated control to ensure the safety of the vehicle.
In this embodiment, when the absolute value of the predicted lateral load transfer rate is smaller than the safety threshold and the yaw stability condition is the safety condition, the control action is not executed.
In this embodiment, when the absolute value of the predicted lateral load transfer rate is smaller than the safety threshold, and the yaw stability operating mode is an unstable operating mode, the system is in the steering drivability optimization mode, only yaw stability control is performed, the vehicle is steered at high speed and the yaw and roll motions are both in the stable region, and the drivability of the vehicle is optimized through direct yaw moment control.
In this embodiment, when the absolute value of the predicted lateral load transfer rate is smaller than the safety threshold and the yaw stability operating condition is the limit operating condition, the system is in the yaw stability control mode, and first meets the yaw stability control target and then meets the roll stability control target. The yaw motion of the vehicle breaks through a stable area, the side-rolling motion is in the stable area, the posture of the vehicle body is adjusted by using the oil-gas suspension on the basis that the direct yaw moment control system adjusts the driving force of the hub motor, the vertical load distribution of the inner and outer wheels of the vehicle is optimized, and the stability margin of the vehicle is improved.
In this embodiment, when the absolute value of the predicted lateral load transfer rate is greater than or equal to the safety threshold and the yaw stability operating condition is an unstable operating condition, the system is in the anti-roll control mode, and first meets the roll stability control target and then meets the yaw stability control target. The roll motion of the vehicle breaks through a stable area, the yaw motion is in the stable area, the roll stability control system controls the height of the mass center and the roll posture of the vehicle, and meanwhile, in order to prevent the fluctuation of the operation stability caused by the vertical load change of the wheels, the yaw stability control system of the vehicle works, and the neutral steering characteristic of the vehicle is guaranteed.
In this embodiment, when the absolute value of the predicted lateral load transfer rate is greater than or equal to the safety threshold and the yaw stability condition is the limit condition, the system is in the limit stability control mode. The yaw motion and the roll motion of the vehicle break through a stable area, the two subsystems are in working states, and due to the coupling relation of the transverse motion and the vertical motion of the vehicle, the adjustment of the oil-gas suspension can cause the fluctuation of a vertical load and influence the yaw stability; the adjustment of the direct yaw moment exacerbates the roll motion of the vehicle, and therefore the coupled coordinated control of the two subsystems first satisfies the roll stability control target and reduces the target yaw moment for yaw stability.
Claims (19)
1. The utility model provides an in-wheel motor drive cross country vehicle yaw and stability integrated control method that heels which characterized in that: obtaining vehicle operation parameters, obtaining a transverse load transfer rate and a transverse motion balance equation at the current moment, and then obtaining a predicted transverse load transfer rate at the next moment; determining a yaw stability working condition according to the yaw angular velocity and the centroid slip angle;
when the absolute value of the yaw angular velocity is smaller than the yaw angular velocity threshold value and the absolute value of the centroid slip angle is smaller than the centroid slip angle threshold value, the yaw stability working condition is a safe working condition and does not execute the control action;
and determining a control mode of the yaw and roll integrated control system according to the predicted lateral load transfer rate and the yaw stability working condition, firstly controlling the yaw stability when the absolute value of the predicted lateral load transfer rate is less than a safety threshold, and firstly controlling the roll stability and then controlling the yaw stability when the absolute value of the predicted lateral load transfer rate is greater than or equal to the safety threshold.
2. The integrated yaw and roll stability control method for the in-wheel motor driven off-road vehicle as claimed in claim 1, wherein: when the absolute value of the yaw angular velocity is larger than or equal to the yaw angular velocity threshold and the absolute value of the mass center side slip angle is larger than or equal to the mass center side slip angle threshold, the working condition of the yaw stability is a limit working condition, a yaw stability control mode is entered, the yaw stability is controlled firstly, and then the side slip stability is controlled.
3. The integrated yaw and roll stability control method for the in-wheel motor driven off-road vehicle as claimed in claim 1, wherein: and when the absolute value of the yaw angular velocity is smaller than the yaw angular velocity threshold or the absolute value of the centroid slip angle is smaller than the centroid slip angle threshold, the yaw stability working condition is an unstable working condition, the anti-roll control mode is entered, the roll stability is controlled firstly, and then the yaw stability is controlled.
4. The integrated yaw and roll stability control method for the in-wheel motor driven off-road vehicle as claimed in claim 1, wherein: when the absolute value of the yaw angular velocity is larger than or equal to the yaw angular velocity threshold and the absolute value of the centroid side deviation angle is larger than or equal to the centroid side deviation angle threshold, the yaw stability working condition is a limit working condition, a limit stability control mode is entered, the roll stability is controlled firstly, then the yaw stability is controlled, and the direct yaw moment is limited.
5. The integrated control method for yaw and roll stability of the in-wheel motor driven off-road vehicle as claimed in any one of claims 2 to 4, wherein: the roll stability control method comprises the steps of determining a centroid target height according to a vehicle speed and a predicted transverse load transfer rate, obtaining a target roll angle through transverse acceleration, finally obtaining a target height of each suspension according to the centroid target height, the target roll angle and a target pitch angle, and adjusting an actual roll angle to reach the target roll angle by controlling the target height of each suspension.
6. The integrated yaw and roll stability control method for the in-wheel motor-driven off-road vehicle according to claim 5, wherein: when the vehicle speed is lower than the set vehicle speed, the safety threshold value for predicting the transverse load transfer rate is a first safety threshold value, and when the absolute value of the predicted transverse load transfer rate is lower than the first safety threshold value, the centroid target height is a first centroid height; and when the absolute value of the predicted transverse load transfer rate is greater than or equal to the first safety threshold, the centroid target height is a third centroid height.
7. The integrated yaw and roll stability control method for the in-wheel motor-driven off-road vehicle according to claim 6, wherein: when the vehicle speed is greater than or equal to the set vehicle speed, the safety threshold for predicting the transverse load transfer rate is a second safety threshold, and when the absolute value of the predicted transverse load transfer rate is smaller than the second safety threshold, the centroid target height is a second centroid height; and when the absolute value of the predicted transverse load transfer rate is greater than or equal to the second safety threshold, the centroid target height is a third centroid height.
8. The integrated yaw and roll stability control method for an in-wheel motor driven off-road vehicle as claimed in claim 7, wherein: the first safety threshold is greater than a second safety threshold.
9. The integrated yaw and roll stability control method for an in-wheel motor driven off-road vehicle as claimed in claim 7, wherein: the first centroid height, the second centroid height and the third centroid height decrease in sequence.
10. The integrated yaw and roll stability control method for the in-wheel motor-driven off-road vehicle according to claim 1, wherein: the predicted transverse load transfer rate PLTR is
Wherein LTR is a lateral load transfer rate, t0Is the current time, at is the calculation period.
11. The integrated yaw and roll stability control method for an in-wheel motor-driven off-road vehicle according to claim 10, wherein: the transverse load transfer rate LTR is
Wherein h isgIs the vehicle center of mass height, twIs the track width of ayIs the vehicle lateral acceleration, g is the gravitational acceleration,
is the roll angle.
12. The integrated yaw and roll stability control method for an in-wheel motor driven off-road vehicle as claimed in claim 11, wherein: the transverse motion balance equation is
Wherein beta is the centroid slip angle,
m is the vehicle mass, a is the distance from the center of mass to the front axle, b is the distance from the center of mass to the rear axle, kfIs the tire sidewall deflection stiffness, k, of the front wheelrIs the tire sidewall deflection stiffness, V, of the rear wheelxIs the longitudinal vehicle speed, γ is the yaw rate, and δ is the front wheel angle.
13. The integrated yaw and roll stability control method for the in-wheel motor-driven off-road vehicle according to claim 5, wherein: the target roll angle
Is composed of
Wherein, ayIs the lateral acceleration of the vehicle, c1、c2、c3、c4Are all constant, and c1＝-c2，c3＝-c4。
14. The integrated control method for yaw and roll stability of the in-wheel motor driven off-road vehicle according to any one of claims 1 to 4, characterized in that: the yaw stability control method includes controlling a yaw rate and a centroid yaw angle by controlling a direct yaw moment.
15. The integrated control method for yaw and roll stability of the in-wheel motor driven off-road vehicle according to any one of claims 1 to 4, characterized in that: the method for determining the yaw stability working condition comprises the steps of constructing a two-dimensional phase plane coordinate system according to the yaw velocity and the centroid side deviation angle, determining a parameter domain of each yaw stability working condition in the coordinate system and an activation function of each yaw stability working condition, and when the activation functions meet the activation conditions of the yaw stability working conditions, locating the yaw stability working conditions.
16. The integrated yaw and roll stability control method for an in-wheel motor-driven off-road vehicle according to claim 14, wherein: when the yaw stability working condition is a safe working condition, the activation function h of the safe working condition3(X) is
h3(X)＝H9(X)
When the yaw stability working condition is an unstable working condition, the activation function h of the unstable working condition2(X) is
When the yaw stability working condition is the limit working condition, the activation function h of the limit working condition1(X) is
Wherein,
wherein X ═ β γ]TThe number L of the center points of the parameter domain of the working condition of the yaw stability is 9 and C is the coordinate of the current momentjThe coordinates of the central point of the jth parameter domain; σ is a shape parameter, representing the distance of a center point of the parameter domain from the boundary of the parameter domain.
17. The integrated yaw and roll stability control method for an in-wheel motor driven off-road vehicle as claimed in claim 16, wherein: activating function h under safe working condition3(X) is less than the activation function h3Threshold value h of (X)3(X)thAnd in the meantime, the yaw stability working condition is a safety working condition.
18. The yaw and roll stability integrated control method of the in-wheel motor driven off-road vehicle according to claim 17, characterized in that: activating function h under safe working condition3(X) is greater than or equal to the activation function h3Threshold value h of (X)3(X)thTime and unsteady regime of the activation function h2(X) is less than the activation function h2Threshold value h of (X)2(X)thIn the meantime, the yaw stability condition is an unstable condition.
19. The integrated yaw and roll stability control method for an in-wheel motor driven off-road vehicle as claimed in claim 17, wherein: activating function h under safe working condition3(X) is greater than or equal to the activation function h3Threshold value h of (X)3(X)thTime and unsteady regime of the activation function h2(X) is greater than or equal to the activation function h2Threshold value h of (X)2(X)thAnd in time, the working condition of yaw stability is a limit working condition.
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| CN112758081B (en) * | 2021-04-02 | 2022-07-08 | 吉林大学 | Distributed electric automobile motor thermal protection control method |
| CN113147735B (en) * | 2021-04-15 | 2022-05-06 | 浙江理工大学 | Differential braking/driving coordination rollover prevention control system and control method thereof |
| TWI789899B (en) * | 2021-09-10 | 2023-01-11 | 威剛科技股份有限公司 | Power adjusting system and method thereof of autonomous mobile device |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106004870A (en) * | 2016-06-23 | 2016-10-12 | 吉林大学 | Vehicle stability integrated control method based on variable-weight model prediction algorithm |
| CN108162955A (en) * | 2017-12-28 | 2018-06-15 | 长沙理工大学 | A kind of vehicle active anti-rollover control system and method with time lag compensation |
| CN109606352A (en) * | 2018-11-22 | 2019-04-12 | 江苏大学 | A kind of tracking of vehicle route and stability control method for coordinating |
| CN111391595A (en) * | 2020-03-02 | 2020-07-10 | 南京林业大学 | Vehicle rollover prevention active tilt model prediction control method |
| CN111731265A (en) * | 2019-03-25 | 2020-10-02 | 广州汽车集团股份有限公司 | Method and system for predicting stability state of autonomous vehicle |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7590481B2 (en) * | 2005-09-19 | 2009-09-15 | Ford Global Technologies, Llc | Integrated vehicle control system using dynamically determined vehicle conditions |
| FR2900369B1 (en) * | 2006-04-28 | 2012-08-17 | Renault Sas | METHOD AND DEVICE FOR CONTROLLING AN ACTIVE ANTI-ROLL SYSTEM OF A MOTOR VEHICLE |
| US7571039B2 (en) * | 2006-08-08 | 2009-08-04 | Gm Global Technology Operations, Inc. | Vehicle yaw/roll stability control with semi-active suspension |
| JP6944125B2 (en) * | 2017-11-17 | 2021-10-06 | トヨタ自動車株式会社 | Vehicle behavior control device |
| CN111976409B (en) * | 2019-05-23 | 2022-04-29 | 广州汽车集团股份有限公司 | Control method, system and computer readable medium for vehicle comfort and operation stability |
| CN111204332B (en) * | 2020-02-10 | 2022-07-15 | 哈尔滨工业大学 | Sliding mode control method for optimizing vehicle yaw dynamic performance under all working conditions |
-
2020
- 2020-11-25 CN CN202011336388.4A patent/CN112406853B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106004870A (en) * | 2016-06-23 | 2016-10-12 | 吉林大学 | Vehicle stability integrated control method based on variable-weight model prediction algorithm |
| CN108162955A (en) * | 2017-12-28 | 2018-06-15 | 长沙理工大学 | A kind of vehicle active anti-rollover control system and method with time lag compensation |
| CN109606352A (en) * | 2018-11-22 | 2019-04-12 | 江苏大学 | A kind of tracking of vehicle route and stability control method for coordinating |
| CN111731265A (en) * | 2019-03-25 | 2020-10-02 | 广州汽车集团股份有限公司 | Method and system for predicting stability state of autonomous vehicle |
| CN111391595A (en) * | 2020-03-02 | 2020-07-10 | 南京林业大学 | Vehicle rollover prevention active tilt model prediction control method |
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