CN110606079B - Layered control vehicle rollover prevention method and multi-shaft distributed driving vehicle - Google Patents
Layered control vehicle rollover prevention method and multi-shaft distributed driving vehicle Download PDFInfo
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Abstract
The invention discloses a layered control vehicle rollover prevention method and a multi-axis distributed driving vehicle. The method comprises the steps that a layered control structure is adopted, an upper-layer controller performs combined control of active roll moment and differential braking based on a sliding mode variable structure method, a roll angle is selected as a main reference index of rollover prevention control, and an active roll moment and a differential braking torque value are output by taking the deviation of an ideal roll angle and an actual roll angle and the deviation of an ideal yaw angular velocity and an actual yaw angular velocity as inputs; the middle-layer controller realizes reasonable distribution of the active roll moment among all suspension actuating mechanisms based on an active set method; and finally, the lower layer controller performs driving anti-skid control aiming at the wheel skid condition possibly caused by the middle layer control, and eliminates the negative influence of vertical force change on the longitudinal stress of the wheel. The invention adopts a layered control structure, can fully exert the advantages of two rollover prevention methods, and further improves the running stability of the vehicle by combining the anti-skidding control of the vehicle.
Description
Technical Field
The invention belongs to the technical field of active safety of electric automobiles, and particularly relates to a layered control vehicle rollover prevention method and a multi-axis distributed driving vehicle.
Technical Field
With the development of economy, the number of automobiles in the world continues to increase, roads become crowded, and the danger of automobile traveling becomes great. According to statistics, 15285 total rollover accidents of a heavy truck in 2016 in the United states account for only 3.04 percent of the total annual accidents of the truck, but the number of casualty accidents in the rollover accidents is as much as 7285, the percentage of the casualty accidents in the total accidents is as high as 47.66 percent, so that the fact that the rollover casualty rate of the heavy truck is quite high can be seen, and almost half of casualties can occur as long as the rollover occurs.
The lateral stability of the vehicle is an important factor influencing the running safety of the vehicle, the vehicle is easy to have a rollover accident under the condition of lateral instability, which is particularly dangerous for freight vehicles and special vehicles with too high mass centers and small wheelbases and mass center heights, and the additional sprung mass brought by strong carrying capacity means the reduction of the operating stability of the vehicle, so that the rollover accident is easy to occur when the vehicle is in the limit working condition.
Patent CN109733382A proposes an automobile rollover prevention method based on model predictive control, but the method is only suitable for rollover prevention control of a two-axis vehicle; patent CN107499271A proposes a passenger car rollover prevention control system and method based on an electronic control air suspension and an electronic control brake system, which effectively perform rollover control on a passenger car in a manner of coordinated control of a suspension system and a brake system, so as to improve the rollover prevention performance of the passenger car, but do not perform stability control on the distribution of the vertical force of an active suspension of a multi-axle distributed drive vehicle and the vehicle slippage condition possibly caused by the vertical force change.
Disclosure of Invention
The invention provides a layered control vehicle rollover prevention method and a multi-axis distributed driving vehicle, aiming at solving the defects in the background art. The invention adopts a three-layer layered control method, realizes rollover prevention by active roll moment and differential braking combined control aiming at a multi-shaft distributed driving vehicle, simultaneously realizes longitudinal anti-skidding control, and avoids adverse effects caused by middle-layer active roll moment distribution control.
The invention discloses a vehicle rollover prevention method based on hierarchical control, which comprises the following steps:
measuring the steering wheel angle and the vehicle speed of the vehicle, and inputting the steering wheel angle and the vehicle speed to the upper-layer rollover prevention combined control system;
the upper-layer rollover prevention combined control system calculates an active roll moment and a differential braking moment, and uses the calculated active roll moment as an input variable of the middle-layer suspension vertical force optimization distribution system;
the middle-layer suspension vertical force optimized distribution system realizes vertical force distribution for the active suspension actuator;
the lower-layer driving and braking antiskid control system calculates driving torque based on a sliding mode variable structure method based on differential braking torque and an ideal slip ratio as a target.
Preferably, the upper-layer rollover prevention combined control system takes the steering wheel angle signal as an input variable, and calculates an ideal roll angle and an ideal yaw rate of output variables through a vehicle three-degree-of-freedom reference model.
Preferably, the active roll moment is calculated based on a fuzzy gain adjusted sliding mode variable structure control algorithm.
Preferably, the differential braking torque is calculated based on a sliding mode variable structure control algorithm.
Preferably, the vertical force distribution of the active suspension actuator is specifically control of the proportion of the active anti-roll moment distributed between the front axle active suspension actuator and the middle and rear axle active suspension actuator and the proportion distributed between the left side active suspension actuator and the right side active suspension actuator.
Preferably, the vertical force distribution to the active suspension actuator is achieved based on an active set method.
Preferably, the active set-based method for realizing vertical force distribution to the active suspension actuator specifically comprises the following steps:
setting the average distribution of the total control torque of the initial moment among the front axle, the middle rear axle and the left side wheel and the right side wheel by actuators at all wheels;
determining constraint conditions of a design variable X of an active set method, wherein the constraint conditions consider the adhesion condition of wheels on a good road surface, the requirement of a transverse load transfer rate, the requirement of vertical dynamic force on the tension and compression of a vehicle body, the output requirement of active roll moment and the output capacity of an active suspension actuator;
determining a valid set of constraints of all constraints around the iteration feasible point;
and obtaining an optimal solution of an objective function under the constraint through multiple iterations, wherein the objective function is the average relative dynamic load of each tire, obtaining the optimal vertical force distribution proportion of the active suspension actuator, and calculating the vertical control force required by the active suspension actuators of the left front axle, the right front axle, the left middle rear axle and the right middle rear axle.
Preferably, the calculating of the active roll moment comprises in particular the steps of:
calculating the roll angle deviation e and its deviation rate
The calculation process is as follows:
e＝φ0-φ
selecting an exponential approximation law, and designing a linear switching function s of the sliding mode variable structure controller;
in the formula, c is a constant and is a switching coefficient, k represents sliding mode switching gain, and c is more than 0 and is more than 0, and k is more than 0;
sgn represents a sign function, whose expression is:
the final sliding mode controller is designed as follows;
in the formula,
the control equation for the upper layer rollover prevention control system based on the 39DOF vehicle model yields:
the method for determining the switching coefficient comprises the following steps: the discourse domain of the input variable roll angle deviation e in the fuzzy controller is [0,15], and the discourse domain of the output variable switching gain is [0,1.5 ]; the dip angle deviation e and the linguistic value set of the switching gain are all { ZO, PM, PB }, and represent { zero, middle and large } in natural language; the input variable and the output variable membership function adopt a triangular-S type mixed membership function, and the ambiguity resolution method adopts an area gravity center method. Preferably, the lower layer drive and brake slip control system is targeted to a reference rotational angular velocity corresponding to a slip rate of 20%.
The invention also relates to a multi-axis distributed driving vehicle which is characterized in that the vehicle rollover prevention method adopting the layered control is adopted.
The invention has the following beneficial effects:
1. the layered stability control frame is adopted, the middle layer control system can realize the optimal distribution of the active roll moment calculated by the upper layer control system among the active suspensions of the multi-axis distributed driving vehicle, and the lower layer control system carries out longitudinal anti-slip control aiming at the vehicle slip condition possibly caused by the vertical force variation phenomenon of the middle layer and the vertical force variation of the middle layer so as to avoid the adverse effect of the middle layer distribution control and realize the comprehensive performance requirement of the vehicle in the driving process.
2. The combined control of the active roll moment and the differential braking is adopted, so that the advantages of two control methods can be fully exerted, and the defects caused by the use of a single method are overcome.
Specifically, when the roll attitude of the vehicle deviates a little, the roll control is not enough to influence the yaw parameter, at this time, firstly, the active roll moment system is adopted to control, the direct and effective advantages of the suspension control are fully exerted, and when the vehicle body rolls seriously or the change rule of the yaw angular speed of the vehicle is obviously changed by the active roll moment control, the differential braking system participates in the working condition, on one hand, the anti-roll capability of the vehicle is further improved through braking and decelerating, and on the other hand, the negative influence of the roll moment control in the yaw direction is compensated through the action of the differential additional yaw moment.
3. The gain coefficient in the sliding mode variable structure control of the active roll moment is determined by adopting a fuzzy control-based method, and compared with the constant switching gain in the traditional sliding mode control system, the gain coefficient can be changed continuously along with the change of the control effect, and the jitter phenomenon in the control process can be improved to a certain extent.
4. And the roll inclination angle and the yaw velocity are taken as anti-rollover control reference indexes, and compared with the selection of the transverse load transfer rate LTR as an index, the roll stability control of the vehicle can be directly realized according to the deviation of the control reference indexes.
Drawings
FIG. 1 is a schematic diagram of the principle of the layered anti-rollover coordination control system of the present invention
FIG. 2 is a schematic block diagram of the fuzzy-sliding mode control-based vehicle rollover prevention control principle of the invention
FIG. 3 is a schematic diagram of the process of active roll moment optimization distribution by the active set method according to the present invention
Detailed Description
The technical scheme of the invention is further explained in detail by combining the attached drawings:
as shown in fig. 1, in the hierarchical control structure of the present invention, an upper-layer rollover prevention combined control system is provided in an upper left-corner dashed frame, a double-closed-loop control structure is adopted, an active roll moment and a differential braking moment are calculated for vehicle rollover prevention control, the calculated active roll moment is used as an input variable of a middle-layer suspension vertical force optimal distribution system, the active roll moment is distributed to each active suspension system, and finally, a lower-layer driving and braking anti-skid control system performs driving anti-skid control on a wheel skid phenomenon possibly caused by the middle-layer suspension vertical force optimal distribution control by taking a slip rate as a control target. The control process of the invention specifically comprises the following steps:
step 1), measuringSteering wheel angle of vehiclesThe vehicle speed v, the yaw angular velocity r and the roll angle phi are input into an upper-layer rollover prevention combined control system;
the control process of the upper-layer rollover prevention combined control system comprises the following steps:
step 2), taking the steering wheel angle signal s as an input variable, and calculating an ideal lateral inclination angle phi of an output variable through a three-degree-of-freedom reference model of the vehicle0And ideal yaw rate r0；
Taking an eight-axis distributed driving vehicle as an example, the specific calculation process of the step 2) is as follows:
at a side inclination angle phi and a lateral velocity vyYaw rate r and roll rate
As state variables, i.e.
Steering wheel angle signalsAs an input variable u, with an ideal roll angle phi0And ideal yaw rate r0Is the output variable y;
establishing a three-degree-of-freedom whole vehicle state equation as follows:
wherein A ═ F-1G，B＝F-1HC＝[1 0 1 0]
In the formula, msRespectively representing the mass of the whole vehicle and the suspension mass;
vx、vyrespectively representing longitudinal and lateral vehicle speeds of the vehicle;
φ、
respectively representing a roll angle, a roll angle speed and a roll angle acceleration;
r、
representing the yaw velocity and the yaw acceleration of the vehicle around the z-axis;
Ixzrepresents the product of the inertia of the vehicle pair ox with the oz axis;
Ixrepresenting the moment of inertia of the vehicle about the x-axis;
Izrepresenting the moment of inertia of the vehicle about the z-axis;
Lirepresents the distance from the ith axis to the centroid;
Cirepresenting the i-th axle suspension roll stiffness;
h represents the distance of the center of gravity of the suspended mass from the roll axis;
Ksi、Csirespectively representing the stiffness and damping of the ith suspension.
The control equation of the upper-layer rollover prevention control system is established as follows:
with xc＝[r ωx]TIs a target state variable, where ωxAnd r are state variables corresponding to active roll moment control and differential braking control in the upper-layer rollover prevention combined control system respectively. By uc＝[FX MX]TAs a target control input variable, wherein FXRepresenting differential braking torque, MXRepresenting an active roll moment;
obtaining a nonlinear state equation based on a vehicle model to be analyzed to obtain a control equation;
the nonlinear equation of state is preferably derived based on a 39DOF vehicle model, and the resulting control equation is as follows:
in the formula, u, vzRespectively representing the longitudinal, lateral and vertical speeds of the vehicle;
ωx、ωyand r respectively represent rotation angular velocities of the vehicle body around an x-axis, a y-axis and a z-axis of a vehicle coordinate system;
Fx、Fy、Fzrespectively representing longitudinal, lateral and vertical forces of the vehicle at X, Y, Z coordinates;
Mz、Mx、Myrespectively representing the yaw moment borne by the vehicle in the directions of the z axis, the x axis and the y axis;
M、mbrespectively representing the mass of the whole vehicle and the mass of the vehicle body;
Ix、Iy、Izrepresenting the moment of inertia of the vehicle about the x, y and z axes, respectively;
αsand f represents the lane gradient and the rolling resistance coefficient, respectively;
CDand A represents the air resistance coefficient and the frontal area, respectively;
phi and psi denote roll and pitch angles of the vehicle body, respectively;
herepresenting the sprung mass centre-of-mass to roll centre distance.
Step 3), calculating the active roll moment based on a sliding mode variable structure control algorithm of fuzzy gain adjustment;
as shown in fig. 2, a schematic block diagram of the calculation of the active roll moment based on the sliding mode variable structure control algorithm of the fuzzy gain adjustment.
Step 3) comprises the following steps:
step 3.1.1), calculating the roll angle deviation e and the deviation rate thereof
The calculation process is as follows:
e＝φ0-φ
step 3.1.2), selecting an exponential approximation law and designing a linear switching function s of the sliding mode variable structure controller;
in the formula, c is a constant and is a switching coefficient, k represents sliding mode switching gain, and c is more than 0 and is more than 0, and k is more than 0;
sign represents a sign function, and the expression is as follows:
step 3.1.3), designing a final sliding mode controller;
in the formula,
the control equation of the upper-layer rollover prevention control system based on the 39DOF vehicle model is obtained as follows:
wherein, the switching coefficient of the step 3.1.2) is determined by adopting a fuzzy control method, and the specific steps are as follows:
step 3.2), the domain of the input variable roll angle deviation e in the fuzzy controller is [0,15], and the domain of the output variable switching gain is [0,1.5 ]; the dip angle deviation e and the linguistic value set of the switching gain are all { ZO, PM, PB }, and represent { zero, middle and large } in natural language; the input variable and the output variable membership function adopt a triangular-S type mixed membership function, and the ambiguity resolution method adopts an area gravity center method.
Step 4), calculating differential braking torque F based on sliding mode variable structure control algorithmx；
Step 4) comprises the following specific steps:
step 4.1), calculating yaw rate deviation erAnd its deviation ratio
The calculation process is as follows:
er＝r0-r
step 4.2), selecting an exponential approximation law, and designing a linear switching function s of the sliding mode variable structure controller;
in the formula, c is a constant and is a switching coefficient, k represents sliding mode switching gain, and c is more than 0 and is more than 0, and k is more than 0;
sgn represents a sign function, whose expression is:
step 4.3), designing a final sliding mode controller;
in the formula, g 'and f' are obtained from the control equation of the upper layer rollover prevention control system based on the 39DOF vehicle model:
under the action of the upper-layer rollover prevention combined control system, the active roll moment required for preventing the vehicle body from rolling over is obtained through fuzzy control-sliding mode variable structure control calculation, and the active roll moment can enable the vehicle roll angle to realize safe lateral motion according to the change rule of the reference track.
The control of the total active roll moment on a vehicle system is finally realized through an active suspension actuating mechanism, so that the vertical force distribution control of an active suspension actuator is realized by adopting a middle-layer suspension vertical force distribution optimization control system.
The invention simplifies the actuating mechanism of the active suspension of the whole vehicle to each wheel and divides the actuating mechanism into a left front axle actuating area and a right front axle actuating area for supporting a driver cabin, and a left middle rear axle actuating area and a right middle rear axle actuating area for bearing goods according to the positions of the wheels. The front bridge execution area comprises the left front bridge execution area and the right front bridge execution area, the middle rear bridge execution area comprises the left middle rear bridge execution area and the right middle rear bridge execution area, the left side execution area comprises the left front bridge execution area and the left middle rear bridge execution area, and the right side execution area comprises the front right bridge execution area and the right middle rear bridge execution area.
Therefore, the vertical force distribution of the active suspension actuator can be converted into the control of the distribution ratio of the active anti-roll moment between the front axle execution area and the middle and rear axle execution area and the distribution ratio between the left side execution area and the right side execution area. That is, the distribution control of the active suspension actuators can be converted into the control of the distribution proportion of the active anti-roll moment between the front axle active suspension actuator and the middle and rear axle active suspension actuator and the distribution proportion between the left side active suspension actuator and the right side active suspension actuator.
Under the action of active roll moment control, on one hand, the lateral attitude of a vehicle body can be effectively adjusted, and on the other hand, the dynamic vertical force at the wheel can be changed, specifically, the pressure-side pressure of a suspension is increased, and the tension-side tension is increased. Therefore, from the viewpoint of improving driving safety, optimal distribution control is carried out with the aim of reducing the vertical relative dynamic load of the wheels.
The control process of the middle-layer suspension vertical force distribution optimization system comprises the following steps:
step 5), taking the active roll moment calculated in the step 3) as the input of the middle-layer controller, and performing active roll moment prevention optimal distribution on each active suspension actuator based on an active set method;
based on the active suspension actuating mechanism subarea, a design variable X is an optimal distribution proportion of the active roll moment:
X＝[kx1,kx2]T
wherein k isx1The proportion of the moment between the front axle active suspension actuator and the middle and rear axle active suspension actuator is kx2The proportion of the moment between the left active suspension actuator and the right active suspension actuator is distributed.
As shown in fig. 3, the flow diagram of the active set method of the mid-level suspension vertical force distribution optimization system specifically includes the following steps:
and step 5.1), setting the initial simulation point as X ═ 0.25,0.5, and indicating that the total control torque at the initial moment is evenly distributed among the front axle, the middle axle, the rear axle and the left wheel and the right wheel by the actuators at all wheels.
And 5.2) determining the constraint condition of the design variable X. The constraint condition considers the adhesion condition of the wheel on a good road surface, the requirement of transverse load transfer rate, the requirement of vertical dynamic force on the tension and compression of a vehicle body, the output requirement of active roll moment, the output capacity of an active suspension actuator and the like, and the mathematical expression is in a simplified form
The specific expression is as follows:
wherein, FxiIndicating the longitudinal force, F, experienced by each wheelzsdiRepresents the total load in the vertical direction at each wheel, mu represents the road adhesion coefficient, FzliIndicating the vertical load on the ith axle wheel of the left execution area, FzriIndicating the vertical load, Δ F, on the ith axle wheel in the right actuating zoneziIndicating the vertical force at each wheel, FmaxRepresenting the limit value of vertical force, K, of a single wheelx1、Kx1Then the boundary limits of the distribution coefficients are respectively expressed and influenced by the output capability of the active suspension actuator, n is the total axle number, LTRmaxThe maximum transverse load transfer rate;
step 5.3), determining an effective constraint set in all constraints around the iteration feasible point;
step 5.4), obtaining an optimal solution X of an objective function under the constraint through multiple iterations, wherein the objective function is the average relative dynamic load of each tire, and the expression is as follows:
wherein, FzdiRepresenting the vertical dynamic load at each wheel of the vehicle, FzsdiThe total load in the vertical direction at each wheel is shown, and m represents the total number of tires.
Step 5.5), calculating the optimal vertical force distribution proportion of the active suspension actuator according to the step 5.4), and calculating the vertical control force delta F required by the active suspension actuator of the left front axle, the right front axle, the left middle rear axle and the right middle rear axlezfl、ΔFzfr、ΔFzrl、ΔFzrrAnd performing active suspension vertical force control, wherein the specific calculation process of each active suspension vertical force is as follows:
wherein B is a track width;
the optimal moment distribution proportion of the whole vehicle active suspension is obtained by optimally distributing the middle layer of the active roll moment, and the relative dynamic load of the wheels is reduced and the vertical safety is improved due to the influence of the control of the active suspension on the vertical force of the wheels. While the vertical force varies due to the controlled distribution, the longitudinal output capacity of the wheel inevitably varies, taking into account the limiting effect of the tire vertical force on the value of the longitudinal force. Aiming at the wheel slip condition possibly caused by the control of the middle-layer vertical force, the lower-layer driving and braking anti-slip control system performs driving anti-slip control based on a sliding mode variable structure method by taking an ideal slip rate as a target.
The control process of the lower-layer driving and braking antiskid control system comprises the following steps:
step 6), calculating the driving torque T based on a sliding mode variable structure method by taking the ideal slip ratio as a targetw。
Step 6.1), angular velocity w of rotation corresponding to a slip ratio of 20%0Calculating a rotational angular velocity deviation e for a reference targetwAnd its deviation ratio
The calculation process is as follows:
ew＝w0-w
step 6.2), selecting an exponential approximation law, and designing a linear switching function s of the sliding mode variable structure controller;
in the formula, c is a constant and is a switching coefficient, k represents sliding mode switching gain, and c is more than 0 and is more than 0, and k is more than 0;
sgn represents a sign function, whose expression is:
step 6.3), designing a final sliding mode controller;
in the formula,
from the state equations required for individual tire control:
wherein the control output u ═ TwThe state variable x is ω,
it will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
The above-mentioned embodiments, objects, technical solutions and advantages of the present invention are further described in detail, it should be understood that the above-mentioned embodiments are only illustrative of the present invention and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (9)
1. A layered control vehicle rollover prevention method is characterized by comprising the following steps:
measuring the steering wheel angle and the vehicle speed of the vehicle, and inputting the steering wheel angle and the vehicle speed to the upper-layer rollover prevention combined control system;
the upper-layer rollover prevention combined control system calculates an active roll moment and a differential braking moment, and uses the calculated active roll moment as an input variable of the middle-layer suspension vertical force optimization distribution system;
the middle-layer suspension vertical force optimized distribution system realizes vertical force distribution on the active suspension actuator, and specifically comprises the following steps:
setting the average distribution of the total control torque of the initial moment among the front axle, the middle rear axle and the left side wheel and the right side wheel by actuators at all wheels;
determining constraint conditions of a design variable X of an active set method, wherein the constraint conditions consider the adhesion condition of wheels on a good road surface, the requirement of a transverse load transfer rate, the requirement of vertical dynamic force on the tension and compression of a vehicle body, the output requirement of active roll moment and the output capacity of an active suspension actuator;
determining a valid set of constraints of all constraints around the iteration feasible point;
obtaining an optimal solution of an objective function under the constraint through multiple iterations, wherein the objective function is the average relative dynamic load of each tire, obtaining the optimal vertical force distribution proportion of the active suspension actuator, and calculating the vertical control force required by the active suspension actuators of the left front axle, the right front axle, the left middle rear axle and the right middle rear axle;
the lower-layer driving and braking antiskid control system calculates driving torque based on a sliding mode variable structure method based on differential braking torque and an ideal slip ratio as a target.
2. The method of claim 1, wherein: the upper-layer rollover prevention combined control system takes a steering wheel angle signal as an input variable, and calculates an ideal roll angle and an ideal yaw rate of output variables through a three-degree-of-freedom reference model of the vehicle.
3. The method of claim 1, wherein: and calculating the active roll moment based on a sliding mode variable structure control algorithm of fuzzy gain adjustment.
4. The method of claim 1, wherein: and calculating differential braking torque based on a sliding mode variable structure control algorithm.
5. The method of any of claims 1 to 4, wherein: the vertical force distribution of the active suspension actuator is specifically control of the proportion of active anti-roll moment distributed between the front axle active suspension actuator and the middle and rear axle active suspension actuator and the proportion distributed between the left side active suspension actuator and the right side active suspension actuator.
6. The method of any of claims 1 to 4, wherein: vertical force distribution to the active suspension actuator is achieved based on an active set method.
7. The method of any of claims 1 to 4, wherein: the calculating of the active roll moment specifically includes the steps of:
calculating the roll angle deviation e and its deviation rate
The calculation process is as follows:
e＝φ0-φ
wherein phi is a side inclination angle phi0An ideal side inclination angle;
selecting an exponential approximation law, and designing a linear switching function s of the sliding mode variable structure controller;
in the formula, c is a constant and is a switching coefficient, k represents sliding mode switching gain, and c is more than 0 and is more than 0, and k is more than 0;
sgn represents a sign function, whose expression is:
the final sliding mode controller is designed as follows;
in the formula,
the control equation for the upper layer rollover prevention control system based on the 39DOF vehicle model yields:
wherein,
for the acceleration of the roll angle, a fuzzy control method is adopted for determining the switching coefficient, and particularly, the argument field of the input variable roll angle deviation e in a fuzzy controller is [0,15]]The output variable switching coefficient has a discourse field of [0,1.5]](ii) a The roll angle deviation e and the linguistic value set of the switching coefficient are all { ZO, PM, PB }, and represent { zero, middle and large } in a natural language; the membership function of the input variable and the output variable is a triangular-S type mixed membership function, and the ambiguity resolution isThe area gravity center method is selected.
8. The method of any of claims 1 to 4, wherein: the lower layer driving and braking antiskid control system takes a rotation angular velocity corresponding to a slip rate of 20% as a reference target.
9. A multi-axle distributed drive vehicle characterized by a vehicle rollover prevention method employing the hierarchical control according to any one of claims 1 to 8.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111645696B (en) * | 2020-04-28 | 2021-09-10 | 武汉理工大学 | Method for identifying complex off-road working condition of distributed driving off-road vehicle |
| CN111731268B (en) * | 2020-06-01 | 2022-09-30 | 南京航空航天大学 | Vehicle rollover prevention control method considering different driver characteristics |
| CN112172789B (en) * | 2020-09-25 | 2021-07-02 | 河南坐骑科技有限公司 | Anti-rollover control method for active-side-tipping vehicle |
| CN112172540B (en) * | 2020-09-27 | 2021-12-31 | 上海工程技术大学 | Rollover prevention comprehensive control method for distributed drive electric automobile |
| 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 |
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| CN114604234A (en) * | 2022-04-12 | 2022-06-10 | 中国第一汽车股份有限公司 | Vehicle rollover prevention control method and system, computer readable storage medium and vehicle |
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| CN116902108B (en) * | 2023-09-14 | 2023-12-05 | 北京理工大学 | High-speed steering active roll control method and system applied to wheel-leg type vehicle |
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Family Cites Families (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8712639B2 (en) * | 2006-08-30 | 2014-04-29 | Ford Global Technologies | Integrated control system for stability control of yaw, roll and lateral motion of a driving vehicle using an integrated sensing system to determine longitudinal velocity |
| DE102008014104A1 (en) * | 2008-03-13 | 2008-10-23 | Daimler Ag | Controlling handling of automobile, e.g. to anticipate adverse weather conditions, adjusts suspension components as function of road friction |
| WO2011143377A1 (en) * | 2010-05-14 | 2011-11-17 | Lord Corporation | Land vehicles and systems with controllable suspension systems |
| FR3003834B1 (en) * | 2013-03-26 | 2015-04-24 | Univ Blaise Pascal Clermont Ii | METHOD OF REDUCING THE RISK OF TILTING OF A MOTOR VEHICLE EQUIPPED WITH A PILOTABLE SUSPENSION SYSTEM |
| US10543849B2 (en) * | 2016-03-31 | 2020-01-28 | Airgo Ip, Llc | Vehicle operational diagnostics and condition response system |
| US10384672B1 (en) * | 2016-05-11 | 2019-08-20 | Apple Inc. | Vehicle stability control system |
| CN106394560B (en) * | 2016-09-09 | 2018-08-28 | 山东理工大学 | A kind of wheel hub driving electric automobile chassis coordinated control system |
| CN116176201A (en) * | 2016-11-18 | 2023-05-30 | 北极星工业有限公司 | Vehicle with adjustable suspension |
| WO2018173303A1 (en) * | 2017-03-24 | 2018-09-27 | 株式会社ショーワ | Control device and suspension device |
| CN107512262B (en) * | 2017-08-14 | 2018-12-21 | 吉林大学 | A kind of vehicle stability control system tire force distribution method when the driving limited space for execution |
| CN109649376B (en) * | 2017-10-11 | 2021-01-26 | 郑州宇通客车股份有限公司 | Rollover prevention active intervention control method and system |
| CN108146431B (en) * | 2017-12-22 | 2020-08-07 | 天津职业技术师范大学 | Automobile rollover stability integrated control method under limit braking condition |
| CN108891221A (en) * | 2018-07-24 | 2018-11-27 | 山东大学 | A kind of active suspension system and its working method based on mode energy distribution method |
| CN109606352B (en) * | 2018-11-22 | 2020-06-26 | 江苏大学 | Vehicle path tracking and stability coordination control method |
| CN109895579A (en) * | 2019-03-04 | 2019-06-18 | 岭南师范学院 | A kind of braking coupling Active suspension anti-side turns over integrated control device and its control method |
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