阅读说明：本技术 整车半主动悬架系统集成控制方法和系统 (Integrated control method and system for semi-active suspension system of whole vehicle ) 是由 石能芳 戴锐 李建坤 陈定积 毛丽臣 王仲和 王志伟 张毛鹏 覃威 于 2021-08-31 设计创作，主要内容包括：本发明提出一种整车半主动悬架系统集成控制方法和系统,方法包括：获取侧向控制车辆参数、纵向控制车辆参数和当前车速；确定控制所需车辆参数所处的阈值区间,根据各阈值区间与阻尼梯度区间映射数据表分别确定各控制参数对应的阻尼梯度区间,获取与各阻尼梯度区间对应的车速阈值,若当前车速大于阈值,则根据车速与阻尼映射表分别获取侧向和纵向控制阻尼目标值；取阻尼目标值中数值大的作为侧纵向控制阻尼目标值；根据获取的垂向控制阻尼目标值、根据路况确定的阻尼比例值、侧纵向控制阻尼目标值计算输出各减振器阻尼目标值。本发明解决了现有技术在提升舒适性的同时,降低车轮接地性,无法同时实时兼顾整车操纵稳定性的技术问题。(The invention provides a method and a system for integrally controlling a semi-active suspension system of a whole vehicle, wherein the method comprises the following steps: acquiring lateral control vehicle parameters, longitudinal control vehicle parameters and current vehicle speed; determining a threshold interval in which vehicle parameters required for control are located, respectively determining a damping gradient interval corresponding to each control parameter according to each threshold interval and a damping gradient interval mapping data table, acquiring a vehicle speed threshold corresponding to each damping gradient interval, and respectively acquiring lateral and longitudinal control damping target values according to a vehicle speed and damping mapping table if the current vehicle speed is greater than the threshold; taking the larger value of the damping target values as a side longitudinal control damping target value; and calculating and outputting the damping target value of each shock absorber according to the acquired vertical control damping target value, the damping proportion value determined according to the road condition and the lateral longitudinal control damping target value. The invention solves the technical problems that the prior art improves the comfort, reduces the wheel grounding performance and cannot give consideration to the whole vehicle operation stability in real time.)

1. An integrated control method for a semi-active suspension system of a whole vehicle is characterized by comprising the following steps:

acquiring lateral control vehicle parameters, longitudinal control vehicle parameters and current vehicle speed;

determining a lateral control vehicle parameter threshold interval in which lateral control vehicle parameters are positioned, determining a lateral control damping gradient interval according to a mapping data table of the lateral control vehicle parameter threshold interval and the damping gradient interval, acquiring a vehicle speed threshold corresponding to the lateral control damping gradient interval, and acquiring a lateral control damping target value according to the vehicle speed and the damping mapping data table if the current vehicle speed is greater than the vehicle speed threshold;

determining a longitudinal control vehicle parameter threshold interval in which a longitudinal control vehicle parameter is positioned, determining a longitudinal control damping gradient interval according to a mapping data table of the longitudinal control vehicle parameter threshold interval and the damping gradient interval, acquiring a vehicle speed threshold corresponding to the longitudinal control damping gradient interval, and acquiring a longitudinal control damping target value according to a vehicle speed and damping mapping table if the current vehicle speed is greater than the vehicle speed threshold;

taking the lateral control damping target value and the longitudinal control damping target value with a large value as a lateral longitudinal control damping target value;

calculating the final output damping value of the shock absorber according to the acquired vertical control damping target value, the damping proportion value determined according to the road condition and the lateral longitudinal control damping target value:

and finally outputting a damping value which is the damping ratio value x side longitudinal control damping target value + (1-damping ratio value) x vertical control damping target value.

2. The integrated control method for semi-active suspension system of whole vehicle according to claim 1,

the lateral control vehicle parameter includes at least one of steering wheel angular velocity and lateral acceleration.

3. The integrated control method for semi-active suspension system of whole vehicle according to claim 2,

determining a lateral control vehicle parameter threshold interval in which the lateral control vehicle parameter is located, and determining a lateral control damping gradient interval according to a mapping data table of the lateral control vehicle parameter threshold interval and the damping gradient interval comprises: and searching the mapping table of the lateral control vehicle parameter and the lateral control vehicle parameter threshold interval for the steering wheel angular velocity or the lateral acceleration to determine the corresponding lateral control vehicle parameter threshold interval, and determining the lateral control damping gradient interval corresponding to the steering wheel angular velocity or the lateral acceleration according to the mapping data table of the lateral control vehicle parameter threshold interval and the damping gradient interval.

4. The integrated control method for semi-active suspension system of whole vehicle according to claim 2,

and if the lateral control damping gradient intervals respectively determined according to the steering wheel rotating speed and the lateral acceleration are different, taking the interval with a larger value as the lateral control damping gradient interval.

5. The integrated control method for semi-active suspension system of whole vehicle according to claim 1,

the longitudinal control vehicle parameter includes at least one of a rate of change of accelerator pedal opening, a rate of change of brake pedal opening, and a longitudinal acceleration.

6. The integrated control method for semi-active suspension system of whole vehicle according to claim 5,

determining a longitudinal control vehicle parameter threshold interval where a longitudinal control vehicle parameter is located, and determining a longitudinal control damping gradient interval according to a mapping data table of the longitudinal control vehicle parameter threshold interval and the damping gradient interval: and searching a longitudinal control vehicle parameter threshold interval corresponding to the accelerator pedal opening change rate, the brake pedal opening change rate or the longitudinal acceleration on a mapping table of longitudinal control vehicle parameters and longitudinal control vehicle parameter threshold intervals, and searching a longitudinal control damping gradient interval corresponding to the accelerator pedal opening change rate, the brake pedal opening change rate or the longitudinal acceleration according to a mapping data table of the longitudinal control vehicle parameter threshold interval and the damping gradient interval.

7. The integrated control method for semi-active suspension system of whole vehicle according to claim 5,

and if the longitudinal control damping gradient intervals respectively determined according to the accelerator pedal opening change rate, the brake pedal opening change rate and the longitudinal acceleration are different, taking the interval with larger value as the longitudinal control damping gradient interval.

8. The integrated control method for semi-active suspension system of whole vehicle according to claim 1,

the determination process of the damping proportion value is as follows: firstly, acquiring the dynamic stroke of a suspension and the dynamic speed of a shock absorber;

judging a value section of the suspension frame moving stroke and a value section of the shock absorber moving speed, and acquiring road condition information according to a judgment result;

and searching a damping proportion value according to the road condition information in the damping proportion mapping table.

9. The integrated control method for semi-active suspension system of whole vehicle according to claim 1,

the vertical control damping target value is obtained by adopting a hybrid control model of 'skyhook-acceleration' of the 1/4 vehicle semi-active suspension.

10. The integrated control method for semi-active suspension system of whole vehicle according to any one of claims 1-9,

further comprising: and finding out a current value corresponding to the final output damping value from the damping value and current mapping table, and controlling the currents in the left front damping controllable shock absorber, the right front damping controllable shock absorber, the left rear damping controllable shock absorber and the right rear damping controllable shock absorber according to the current value.

11. A control system adopting the integrated control method for the semi-active suspension system of the whole vehicle as claimed in any one of claims 1 to 10, characterized by comprising:

the vertical control module, the lateral and longitudinal combined control module are connected with the integrated coordination control module;

the vertical control module outputs a vertical control damping target value by adopting a mode of a hybrid control model of 'skyhook-acceleration' of a semi-active suspension of an 1/4 vehicle;

the process of longitudinally controlling the damping target value at the output side of the lateral and longitudinal combined control module comprises the following steps:

acquiring lateral control vehicle parameters, longitudinal control vehicle parameters and current vehicle speed;

determining a lateral control vehicle parameter threshold interval in which lateral control vehicle parameters are positioned, determining a lateral control damping gradient interval according to a mapping data table of the lateral control vehicle parameter threshold interval and the damping gradient interval, acquiring a vehicle speed threshold corresponding to the lateral control damping gradient interval, and acquiring a lateral control damping target value according to a vehicle speed and damping mapping table if the current vehicle speed is greater than the vehicle speed threshold;

determining a longitudinal control vehicle parameter threshold interval in which a longitudinal control vehicle parameter is positioned, determining a longitudinal control damping gradient interval according to a mapping data table of the longitudinal control vehicle parameter threshold interval and the damping gradient interval, acquiring a vehicle speed threshold corresponding to the longitudinal control damping gradient interval, and acquiring a longitudinal control damping target value according to a vehicle speed and damping mapping table if the current vehicle speed is greater than the vehicle speed threshold;

taking the lateral control damping target value and the longitudinal control damping target value with a large value as a lateral longitudinal control damping target value;

the process of outputting the final output damping value by the integrated coordination control module is as follows: calculating the final output damping value of the shock absorber according to the acquired vertical control damping target value, the damping proportion value determined according to the road condition and the lateral longitudinal control damping target value:

and finally outputting a damping value which is the damping ratio value x side longitudinal control damping target value + (1-damping ratio value) x vertical control damping target value.

Technical Field

The invention relates to the field of vehicles, in particular to a method and a system for integrally controlling a semi-active suspension system of a whole vehicle.

Background

In the prior art, a damping-adjustable semi-active suspension control method is based on a skyhook control theory in engineering, the theory is only for 1/4 vehicles, the theoretical analysis mainly aims at improving the comfort of sprung mass, and the grounding performance of unsprung mass wheels is sacrificed, so that the driving safety of the vehicle is sacrificed to a certain extent. Even if various derivative control methods based on the ceiling control, such as ceiling-ground ceiling control, give consideration to the control of unsprung mass to a certain extent, the grounding performance is not deteriorated too much, but the lateral (roll) motion and the longitudinal (pitch) motion of the vehicle cannot be controlled from the whole vehicle layer, so that the control stability of the whole vehicle is taken into consideration in real time. Various control algorithms of other reasoning classes are more and more complex, such as skyhook control based on particle swarm optimization algorithm, neural network control and the like, most of the algorithms lack integrated control over the lateral motion and the longitudinal motion of the whole vehicle aiming at 1/4 vehicles, the computational power requirement on a controller is high, larger response time lag is brought actually, real-time convergence cannot be guaranteed, control parameters have no specific physical significance, and the algorithms do not have operability in engineering application.

Disclosure of Invention

Based on the problems, the invention provides an integrated control method and system for a semi-active suspension system of a whole vehicle, and solves the technical problems that the control method in the prior art improves the comfort, reduces the wheel grounding performance, and fails to give consideration to the operation stability of the whole vehicle such as lateral motion, longitudinal motion and the like in real time, and also solves the technical problems that the algorithms have high computational force requirements on a controller, actually bring larger response time lag, and control parameters have no specific physical significance, and do not have operability in engineering application.

The invention provides an integrated control method for a semi-active suspension system of a whole vehicle, which comprises the following steps:

acquiring lateral control vehicle parameters, longitudinal control vehicle parameters and current vehicle speed;

determining a lateral control vehicle parameter threshold interval in which lateral control vehicle parameters are positioned, determining a lateral control damping gradient interval according to a mapping data table of the lateral control vehicle parameter threshold interval and the damping gradient interval, acquiring a vehicle speed threshold corresponding to the lateral control damping gradient interval, and acquiring a lateral control damping target value according to a vehicle speed and damping mapping table if the current vehicle speed is greater than the vehicle speed threshold;

determining a longitudinal control vehicle parameter threshold interval in which a longitudinal control vehicle parameter is positioned, determining a longitudinal control damping gradient interval according to a mapping data table of the longitudinal control vehicle parameter threshold interval and the damping gradient interval, acquiring a vehicle speed threshold corresponding to the longitudinal control damping gradient interval, and acquiring a longitudinal control damping target value according to a vehicle speed and damping mapping table if the current vehicle speed is greater than the vehicle speed threshold;

taking the lateral control damping target value and the longitudinal control damping target value with a large value as a lateral longitudinal control damping target value;

calculating the final output damping value of the shock absorber according to the acquired vertical control damping target value, the damping proportion value determined according to the road condition and the lateral longitudinal control damping target value:

and finally outputting a damping value which is the damping ratio value x side longitudinal control damping target value + (1-damping ratio value) x vertical control damping target value.

In addition, the lateral control vehicle parameter includes at least one of steering wheel angular velocity and lateral acceleration.

In addition, determining a lateral control vehicle parameter threshold interval in which the lateral control vehicle parameter is located, and determining a lateral control damping gradient interval according to a mapping data table of the lateral control vehicle parameter threshold interval and the damping gradient interval comprises: and searching the mapping chart of the lateral control vehicle parameter and the lateral control vehicle parameter threshold interval for the steering wheel angular velocity or the lateral acceleration to determine the corresponding lateral control vehicle parameter threshold interval, and determining the lateral control damping gradient interval corresponding to the steering wheel angular velocity or the lateral acceleration according to the mapping data table of the lateral control vehicle parameter threshold interval and the damping gradient interval.

If the lateral control damping gradient sections determined based on the steering wheel angular velocity and the lateral acceleration are different from each other, the section value is larger and is taken as the lateral control damping gradient section.

Further, the longitudinal control vehicle parameter includes at least one of an accelerator pedal opening change rate, a brake pedal opening change rate, and a longitudinal acceleration.

In addition, determining a longitudinal control vehicle parameter threshold interval where the longitudinal control vehicle parameter is located, and determining a longitudinal control damping gradient interval according to a mapping data table of the longitudinal control vehicle parameter threshold interval and the damping gradient interval: on a mapping chart of longitudinal control vehicle parameters and longitudinal control vehicle parameter threshold intervals, longitudinal control vehicle parameter threshold intervals corresponding to the accelerator pedal opening change rate, the brake pedal opening change rate or the longitudinal acceleration are searched, longitudinal control damping gradient intervals corresponding to the accelerator pedal opening change rate, the brake pedal opening change rate or the longitudinal acceleration are searched according to a mapping data table of the longitudinal control vehicle parameter threshold intervals and the damping gradient intervals, and longitudinal control damping gradient intervals corresponding to the accelerator pedal opening change rate, the brake pedal opening change rate or the longitudinal acceleration are searched according to a mapping data table of the longitudinal control vehicle parameter threshold intervals and the damping gradient intervals.

In addition, if the longitudinal control damping gradient sections respectively determined from the accelerator pedal opening degree change rate, the brake pedal opening degree change rate, and the longitudinal acceleration are different, a section value larger is taken as the longitudinal control damping gradient section.

In addition, the determination process of the damping proportion value is as follows: firstly, acquiring the dynamic stroke of a suspension and the dynamic speed of a shock absorber;

judging a value section of the suspension frame moving stroke and a value section of the shock absorber moving speed, and acquiring road condition information according to a judgment result;

and searching a damping proportion value according to the road condition information in the damping proportion mapping table.

In addition, the vertical control damping target value is obtained by adopting a 1/4 hybrid control model of the skyhook-acceleration of the semi-active suspension of the vehicle.

In addition, the method further comprises the following steps: and finding out a current value corresponding to the final output damping value from the damping value and current mapping table, and controlling the currents in the left front damping controllable shock absorber, the right front damping controllable shock absorber, the left rear damping controllable shock absorber and the right rear damping controllable shock absorber according to the current value.

The invention also provides a control system adopting the integrated control method of the whole vehicle semi-active suspension system, which comprises the following steps:

the vertical control module, the lateral and longitudinal combined control module are connected with the integrated coordination control module;

the vertical control module outputs a vertical control damping target value by adopting a mode of a hybrid control model of 'skyhook-acceleration' of a semi-active suspension of an 1/4 vehicle;

the process of longitudinally controlling the damping target value at the output side of the lateral and longitudinal combined control module comprises the following steps:

acquiring lateral control vehicle parameters, longitudinal control vehicle parameters and current vehicle speed;

determining a lateral control vehicle parameter threshold interval in which lateral control vehicle parameters are positioned, determining a lateral control damping gradient interval according to a mapping data table of the lateral control vehicle parameter threshold interval and the damping gradient interval, acquiring a vehicle speed threshold corresponding to the lateral control damping gradient interval, and acquiring a lateral control damping target value according to a vehicle speed and damping mapping table if the current vehicle speed is greater than the vehicle speed threshold;

determining a longitudinal control vehicle parameter threshold interval in which a longitudinal control vehicle parameter is positioned, determining a longitudinal control damping gradient interval according to a mapping data table of the longitudinal control vehicle parameter threshold interval and the damping gradient interval, acquiring a vehicle speed threshold corresponding to the longitudinal control damping gradient interval, and acquiring a longitudinal control damping target value according to a vehicle speed and damping mapping table if the current vehicle speed is greater than the vehicle speed threshold;

taking the larger value of the lateral control damping target value and the longitudinal control damping target value as a lateral longitudinal control damping target value;

the process of outputting the final output damping value by the integrated coordination control module is as follows: calculating the final output damping value of the shock absorber according to the acquired vertical control damping target value, the damping proportion value determined according to the road condition and the lateral longitudinal control damping target value:

and finally outputting a damping value which is the damping ratio value x side longitudinal control damping target value + (1-damping ratio value) x vertical control damping target value.

Through adopting above-mentioned technical scheme, have following beneficial effect:

the invention solves the technical problems that the control method in the prior art improves the comfort, reduces the wheel grounding performance and cannot give consideration to the whole vehicle control stability in real time, and also solves the technical problems that the algorithms have high computational force requirements on the controller, actually bring larger response time lag, have no specific physical significance to control parameters and have no operability in engineering application. The semi-active suspension system integrated control method provided by the invention can simultaneously and accurately control the vertical motion, the longitudinal motion (pitching motion) and the lateral motion (rolling motion) of the whole vehicle in real time. The vehicle body posture is ensured while the comfort is ensured, so that the operating stability of the vehicle is ensured in real time.

Drawings

FIG. 1 is a flow chart of a method for integrated control of a semi-active suspension system of a finished vehicle according to an embodiment of the present invention;

FIG. 2 is a mapping diagram of lateral control parameter threshold intervals and lateral control damping gradient intervals, a mapping diagram of longitudinal control parameter threshold intervals and longitudinal control damping gradient intervals, and a mapping diagram of vehicle speed and damping gradient intervals according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of integrated coordination control provided by an embodiment of the present invention;

FIG. 4 is a schematic diagram of a "ceiling-acceleration" control model provided by an embodiment of the present invention;

FIG. 5 is a flowchart of a method for integrated control of a semi-active suspension system of a finished vehicle according to an embodiment of the present invention;

FIG. 6 is a schematic block diagram of a vehicle semi-active suspension system integrated control system provided in accordance with an embodiment of the present invention;

FIG. 7 is a schematic diagram showing the relationship between the damping ratio, the suspension stroke and the shock absorber operating speed provided by one embodiment of the present invention.

Detailed Description

The present invention is described in further detail below with reference to specific embodiments and the attached drawings. It is intended that the present invention not be limited to the particular embodiments disclosed, but that the present invention be limited only by the appended claims.

Referring to fig. 1 and 3, the invention provides an integrated control method for a semi-active suspension system of a whole vehicle, which comprises the following steps:

s001, acquiring lateral control vehicle parameters, longitudinal control vehicle parameters and the current vehicle speed;

step S002, determining a lateral control vehicle parameter threshold interval where lateral control vehicle parameters are located, determining a lateral control damping gradient interval according to a mapping data table of the lateral control vehicle parameter threshold interval and the damping gradient interval, acquiring a vehicle speed threshold corresponding to the lateral control damping gradient interval, and acquiring a lateral control damping target value according to a vehicle speed and damping mapping table if the current vehicle speed is greater than the vehicle speed threshold;

step S003, determining a longitudinal control vehicle parameter threshold interval where a longitudinal control vehicle parameter is located, determining a longitudinal control damping gradient interval according to a mapping data table of the longitudinal control vehicle parameter threshold interval and the damping gradient interval, acquiring a vehicle speed threshold corresponding to the longitudinal control damping gradient interval, and acquiring a longitudinal control damping target value according to a vehicle speed and damping mapping table if the current vehicle speed is greater than the vehicle speed threshold;

s004, taking the lateral control damping target value and the longitudinal control damping target value with a larger value as the lateral longitudinal control damping target value;

step S005, calculating the final output damping value of the shock absorber according to the acquired vertical control damping target value, the damping proportion value determined according to the road condition and the lateral longitudinal control damping target value:

and finally outputting a damping value which is the damping ratio value x side longitudinal control damping target value + (1-damping ratio value) x vertical control damping target value.

In step S001, parameters to be used, such as lateral control vehicle parameters, longitudinal control vehicle parameters, and current vehicle speed, are first acquired.

In step S002, a lateral control vehicle parameter threshold interval where the lateral control vehicle parameter is located is first determined, then a lateral control damping gradient interval corresponding to the steering wheel angular velocity or lateral acceleration is determined according to a mapping data table of the lateral control vehicle parameter threshold interval and the damping gradient interval, a vehicle speed threshold corresponding to the lateral control damping gradient interval is obtained, and finally the current vehicle speed and the vehicle speed threshold are judged, and a lateral control damping target value is obtained according to a vehicle speed and damping mapping table, so that the advantage of hierarchical judgment is as follows:

compared with single-point threshold control, the embodiment has the advantages that the single-point threshold is replaced by the lateral control damping gradient interval, and the single output value is replaced by the interval gradient output value, so that the fine control feeling can be more comprehensively covered and subdivided, the condition that all the working conditions larger than the threshold are controlled by the single threshold are corresponding to the single large damping to sacrifice the comfort, the sudden riding feeling caused by the sudden change of the damping is avoided, the comfort and the controllability are improved, and the sense of security is improved; the system energy consumption of the damping adjustable shock absorber can be effectively controlled. For example, in a solenoid valve type electronic control shock absorber with a proportional characteristic, the current is in a proportional relation with the damping value, and the larger the damping is, the larger the current is. After a plurality of intervals are subdivided, the corresponding single damping after the single threshold control is triggered can be avoided, the situation that the single damping is always in a large-damping large-current state is avoided, and the energy consumption is saved; the method has the advantages of no complex calculation, high efficiency, real time and full play of expert experience and adjustment, avoids the situation that theoretical calculation cannot fully cover the actual working condition, and can be infinitely expanded.

In step S003, first, a longitudinal control vehicle parameter threshold interval in which a longitudinal control vehicle parameter is located is determined, then a longitudinal control damping gradient interval is determined according to a mapping data table of the longitudinal control vehicle parameter threshold interval and the damping gradient interval, a vehicle speed threshold corresponding to the longitudinal control damping gradient interval is obtained, and finally, whether the current vehicle speed is greater than the vehicle speed threshold is judged, if so, a longitudinal control damping target value is obtained according to a vehicle speed and damping mapping table; the benefit of such a layered judgment is the same as that of the layered judgment in step S002.

In step S004, when the lateral control damping target value and the longitudinal control damping target value are different in value, the lateral control damping target value and the longitudinal control damping target value having the larger value are taken as the lateral control damping target value. This is because the operating condition of the controllability control should be guaranteed primarily with safety, and therefore, a large value is adopted as the lateral longitudinal control damping target value to preferentially ensure safety.

Step S005, calculating the final output damping value of the shock absorber according to the acquired vertical control damping target value, the damping proportion value determined according to the road condition and the lateral longitudinal control damping target value:

and finally outputting a damping value which is the damping ratio value x side longitudinal control damping target value + (1-damping ratio value) x vertical control damping target value.

Optionally, a current value corresponding to the final output damping value is determined, and currents in the left front damping controllable shock absorber, the right front damping controllable shock absorber, the left rear damping controllable shock absorber and the right rear damping controllable shock absorber are controlled according to the current value.

The vertical motion control is to control the comfort of 1/4 vehicles, the side-longitudinal motion control is to control the controllability of the whole vehicle, the control objects are different, and the respective output target values are different, therefore, to coordinate the vertical control and the side-longitudinal control, the vertical control damping target value and the side-longitudinal control damping target value are coordinated to obtain the final output damping value, the calculation formula is: and (3) calculating a final output damping value through the formula, wherein the output damping value is the damping ratio value x side longitudinal control damping target value + (1-damping ratio value) x vertical control damping target value.

The advantages of integrated coordination of the vertical control damping target value and the lateral longitudinal control damping target value are as follows: (1) the damping proportion value of the safety and the comfort is determined by identifying the road condition, so that the safety and the comfort are accurately considered. (2) The damping proportion value set by integrated coordination control is mainly controlled by controllability (lateral control and longitudinal control), so that potential safety hazards during coupling or switching are avoided; (3) the integrated coordination control rule of vertical, longitudinal and lateral control has practical physical significance, and is beneficial to real vehicle debugging; (4) the parameters are set mainly by ensuring the controllability, the common coupling mode based on a calculation model is avoided, the introduction of a large number of differential equation solutions is avoided, the great burden on the calculation force of the controller is avoided, and the response speed and the output delay are ensured. (5) The database based on expert experience is fine and smooth in control, and the practical application can infinitely expand and subdivide to realize comprehensive coverage, high efficiency and real time of all working conditions.

The control method solves the technical problems that the wheel grounding performance is reduced and the control stability control cannot be considered simultaneously in real time while the comfort is improved in the control method in the prior art, and also solves the technical problems that the calculation force requirements of the algorithms on the controller are high, the larger response time lag is brought in practice, the control parameters have no specific physical significance, and the operability is not realized in engineering application.

By adopting the integrated control method for the semi-active suspension of the whole vehicle, the vertical motion, the longitudinal (pitching) motion and the lateral (tilting) motion of the whole vehicle can be simultaneously and accurately controlled in real time. The vehicle body posture motion control of the roll motion and the pitch motion of the whole vehicle is ensured while the comfort is ensured, so that the control stability of the vehicle is ensured in real time.

In one embodiment, the lateral control vehicle parameter includes at least one of steering wheel angular velocity and lateral acceleration. The lateral control uses the steering wheel angular velocity signal to predict driver steering intent and the lateral acceleration signal to identify the state of lateral motion of the vehicle.

Referring to fig. 2, in one embodiment, determining a lateral control vehicle parameter threshold interval in which a lateral control vehicle parameter is located, and determining a lateral control damping gradient interval according to a mapping data table of the lateral control vehicle parameter threshold interval and the damping gradient interval includes: and searching the mapping chart of the lateral control vehicle parameter and the lateral control vehicle parameter threshold interval for the steering wheel angular velocity or the lateral acceleration to determine the corresponding lateral control vehicle parameter threshold interval, and determining the lateral control damping gradient interval corresponding to the steering wheel angular velocity or the lateral acceleration according to the mapping data table of the lateral control vehicle parameter threshold interval and the damping gradient interval.

And the lateral control adopts a mode of layered gradient interval threshold control, a lateral control vehicle parameter threshold interval where the lateral control vehicle parameter is located is determined on the first layer, and the steering wheel turning speed or the lateral acceleration is searched on a mapping chart of the lateral control vehicle parameter threshold interval and the lateral control damping gradient interval to determine the corresponding lateral control damping gradient interval. And on the second layer, comparing the current vehicle speed with a speed threshold value in the lateral control damping gradient interval, and outputting a lateral control damping target value if the current vehicle speed is greater than the interval vehicle speed threshold value. The roll motion is restrained as an expected output lateral control damping target value in a mode of 'layered gradient interval threshold + preset MAP', so that the lateral motion is restrained reasonably.

In one embodiment, the control logic for lateral motion is set as follows:

first-layer judgment: the partial gradient MAP mapping data table is preset, that is, a lateral control damping gradient interval is preset, as shown in the schematic diagram of fig. 2. Judging the steering wheel angular velocity V_steerWhether it is in the lateral control vehicle parameter threshold interval V_{steer_i},V_{steer_i+1}](i∈[1,n]) Or determining lateral acceleration a_latWhether it is in the lateral control vehicle parameter threshold interval [ a ]_{lat_i},a_{lat_i+1}](i∈[1,n]) The output damping interval of each shock absorber is as follows:

wherein i is ∈ [1, n ], x is ∈ [ flfrrlrr ]

Judging the secondary layer: the vehicle speed threshold value V is set in each lateral control damping gradient interval_{V_i-value},i∈[1,n]When the current vehicle speed is greater than the vehicle speed threshold value, a lateral control damping target value is output, and roll motion or roll motion expected to be about to occur is suppressed. The mathematical expression is as follows:

wherein i is E [1, n ], x is E [ flfrrlrr ].

Above, V_steerRepresenting a steering wheel angular velocity; v_{steer_i},V_{steer_i+1}Upper and lower thresholds representing threshold intervals of a lateral control vehicle parameter of steering wheel angular velocity, respectively. a is_latIndicating the lateral acceleration of the vehicle (which CAN be derived from the CAN signal). C_{lat_ix}(i∈[1,n]，x∈[flfrrlrr]) Representing the target value of lateral control damping output in different gradient intervals under lateral control, including the target damping C of the left front shock absorber_{lat_ifl}Right front shock absorber target damping C_{lat_ifr}Left rear shock absorber target damping C_{lat_irl}Target damping C of rear right shock absorber_{lat_irr}。The lateral control damping target value obtained after vehicle speed comparison is shown. fl, fr, rl, rr represent the left front spring, the right front spring, the left rear spring, and the right rear spring, respectively.

Alternatively, the left and right side output damping of the front and rear suspensions under lateral control may be set to be uniform, e.g., the target damping of the front left shock absorber is equal to the target damping C of the front right shock absorber for a certain interval_{lat_ifl}＝C_{lat_ifr}Alternatively, the shock absorber damping for the front and rear axles may be set to be non-uniform.

Optionally, the establishment of the gradient MAP mapping data table: according to different vehicles under different steering angular velocities and different transverse acceleration working conditions, the gradient damping interval and the threshold value, namely the lateral control damping gradient interval, are calibrated and divided according to the expert experience (subjective evaluation) and objective test data. The specific evaluation test condition or scheme is not specifically required.

In one embodiment, if the lateral control damping gradient sections respectively determined according to the steering wheel angular velocity and the lateral acceleration are different, the section value is larger to be taken as the lateral control damping gradient section. And selecting the lateral control damping gradient interval with larger interval value as the lateral control damping gradient interval by taking the safety priority.

In one embodiment thereof, the longitudinally controlled vehicle parameter includes at least one of a rate of change of accelerator pedal opening, a rate of change of brake pedal opening, and longitudinal acceleration.

The longitudinal control predicts the intention of the driver to accelerate or brake by using an accelerator pedal opening change rate or a brake pedal opening change rate, the longitudinal acceleration signal identifies the longitudinal motion (pitching) state of the vehicle, and the target damping value of the longitudinal motion control is output by using 'layering and gradient interval threshold value + preset MAP' to restrain pitching motion as the expectation.

Referring to fig. 2, in one embodiment, a longitudinal control vehicle parameter threshold interval in which a longitudinal control vehicle parameter is located is determined, and a longitudinal control damping gradient interval is determined according to a mapping data table of the longitudinal control vehicle parameter threshold interval and the damping gradient interval: and searching a longitudinal control vehicle parameter threshold interval corresponding to the accelerator pedal opening change rate, the brake pedal opening change rate or the longitudinal acceleration on a longitudinal control vehicle parameter threshold interval mapping chart, and searching a longitudinal control damping gradient interval corresponding to the accelerator pedal opening change rate, the brake pedal opening change rate or the longitudinal acceleration according to a mapping data table of the longitudinal control vehicle parameter threshold interval and the damping gradient interval.

Of course, the brake pedal opening rate may also be characterized by, or equivalently replaced by, the rate of change of the master cylinder pressure, where the brake pedal opening rate may be derived from the pedal opening differential and the master cylinder pressure rate may be derived from the pressure signal differential. The accelerator pedal opening change rate may also be represented by a change rate of an accelerator pedal voltage signal of a general vehicle type or may be replaced with the change rate, wherein the accelerator pedal opening change rate is obtained by differentiating the accelerator pedal opening.

And finally, when the vehicle has roll and pitch at the same time, selecting a larger damping value as a lateral longitudinal control damping target value, identifying the road condition of the whole vehicle, performing integrated decision on the vertical control damping target value and the lateral longitudinal control damping target value, and determining a final output damping value.

In one embodiment, the accelerator pedal/brake pedal opening change rate V is set for longitudinal (pitch) control_pedal(including the accelerator pedal opening change rate V_{pedal_acc}And the brake pedal opening change rate V_{pedal_b}) As a parameter for identifying the acceleration or deceleration of the driver and the driving intention of the driver, or at a longitudinal acceleration a_latAs the state parameters for judging the pitching degree of the vehicle, the two parameters can be used as the triggering rules of longitudinal (pitching) motion control, so that the control system can implement timely and effective control in the initial steering command input stage and the longitudinal motion response process, and the pitching motion of the vehicle is reasonably inhibited.

The control logic for the longitudinal movement is set as follows:

first-layer judgment: a preset gradient interval MAP data table, that is, a preset longitudinal control damping gradient interval, as shown in the schematic diagram of fig. 2. For pitch control, first, the accelerator pedal opening change rate/brake pedal opening change rate V is used_pedal(including the accelerator pedal opening change rate V_{pedal_acc}And brake pedal opening change rate/V_pedalB) whether it belongs to the gradient interval [ V ]_{pedal_i},V_{pedal_i+1}]Or longitudinal acceleration a of the vehicle body_lonWhether it belongs to a gradient interval [ a ]_{lon_i},a_{lon_i+1}]Corresponding to each zoneThe output target damping intervals of the respective shock absorbers in between are as follows.

C_{lon_ix}∈[C_i,C_i+1],if|V_pedal|∈[V_{pedal_i},V_{pedal_i+1}]or|a_lon|∈[a_{lon_i}，a_{lon_i+1}] (3)

Wherein i is ∈ [1, n ], x is ∈ [ flfrrlrr ]

And (3) secondary layer: a vehicle speed threshold value V is set in each longitudinal control damping gradient interval_{V_i-value}，i∈[1，n]And when the vehicle speed is greater than the vehicle speed threshold value, outputting a longitudinal control damping target value to restrain pitching motion or expected impending pitching motion. The mathematical expression is as follows.

C_{posture_ix}＝C_{lon_ix}，if|V_{V_i}|≥V_{V_i-value}，i∈[1，n]，x∈[flfrrlrr] (4)

Above, V_pedalIndicating accelerator pedal opening degree change rate/brake pedal opening degree change rate, V_pedalIncluding the accelerator pedal opening change rate V_{pedal_acc}And the brake pedal opening change rate V_pedal_b；[V_{pedal_i}，V_{pedal_i+1}]Each representing one of the threshold intervals of the pedal opening change rate. a is_lonIndicating the longitudinal acceleration of the vehicle (which CAN be derived from the CAN signal). C_{lon_ix}(i∈[1，n]，x∈[flfrrlrr]) Target damping values of each shock absorber, including a left front shock absorber target damping C, output in different gradient intervals (longitudinal control damping gradient intervals) under longitudinal control_{lon_ifl}Right front shock absorber target damping C_{lon_ifr}Left rear shock absorber target damping C_{lon_irl}Target damping C of rear right shock absorber_{lon_irr}。C_{posrure_ix}(i∈[1，n]，x∈[flfrrlrr]) And indicating the longitudinal control damping target value output by the longitudinal control to the integrated coordination control module.

Alternatively, the left and right side output dampers of the front and rear suspensions under longitudinal control are set to be uniform, e.g., the output damper of the left front shock absorber is equal to the output damper C of the right front shock absorber for a certain section_{lon_ifl}＝C_{lon_ifr}(i∈[1，n]) (ii) a Alternatively, the target damping value of the shock absorber output for the front and rear axles mayThe settings are inconsistent.

Optionally, the establishment of the gradient MAP table: and calibrating the gradient damping interval and each threshold according to different vehicle pedal opening change rates and different longitudinal acceleration working conditions by combining expert experience (subjective evaluation) and objective test data. The specific evaluation test condition or scheme is not specifically required.

In one embodiment, if the longitudinal control damping gradient sections respectively determined according to the accelerator pedal opening degree change rate, the brake pedal opening degree change rate and the longitudinal acceleration are different, the section value is larger to be taken as the longitudinal control damping gradient section. And selecting a longitudinal control vehicle parameter threshold interval with a larger interval value as a longitudinal control vehicle parameter threshold interval with priority on safety.

In one embodiment, the damping ratio value is determined by: firstly, acquiring the dynamic stroke of a suspension and the dynamic speed of a shock absorber;

judging a value section of the suspension frame moving stroke and a value section of the shock absorber moving speed, and acquiring road condition information according to a judgment result;

and searching a damping proportion value according to the road condition information in the damping proportion mapping table.

Firstly, the suspension moves by a stroke D_susAnd the actuating speed V of the shock absorber_damperCombining the road condition database to identify the road condition, and combining the vertical control damping target value C_{d_x}And side longitudinal control damping target value C_{posture_ix}And damping ratio value R_atioAnd coordinating the output to determine a final output damping value.

The road condition identification process comprises the following steps of firstly judging a value section of the suspension frame moving stroke, judging a value section of the damper moving speed, obtaining corresponding road condition information according to the value sections of the suspension frame moving stroke and the damper moving speed, and optionally finding the corresponding road condition information in a mode of searching a mapping relation table:

R_con＝R_{con_i}，if|D_sus|∈[D_susi,D_susi+1]and|V_dam|∈[V_dami,V_dami+1],i∈[1,n] (5)

the value range of the damping proportion value is as follows:

R_atio∈[0，1]，ifR_con∈[R_coni，R_coni+1]，i∈[1，n] (6)

in the above formula, i belongs to [1, n ], x belongs to [ flfrrlrr ]. And the formula (7) is a mapping relation in the damping ratio mapping table.

It can be known from the above that, firstly, the road condition information is obtained according to the suspension dynamic stroke and the shock absorber dynamic speed, and then the corresponding damping proportion value is found in the damping proportion mapping table according to the road condition information, for example, the damping proportion value corresponding to the "straight asphalt road" may be 1.0, and the damping proportion value corresponding to the "scene characteristic road" may be 0.5. FIG. 7 is a diagram showing the relationship between the damping ratio and the dynamic stroke of the suspension and the dynamic speed of the shock absorber.

Referring to FIG. 4, in one embodiment, a vertically controlled damping target value is obtained by using 1/4 a "skyhook-acceleration" hybrid control model of a semi-active suspension of a vehicle.

The vertical control damping target value corresponds to vertical control, controls the vertical motion of the vehicle and controls the vertical motion through a ceiling-acceleration hybrid control theory.

For the semi-active control suspension model of the 1/4 vehicle, the mathematical expression is as follows:

in the formula (I), the compound is shown in the specification,

wherein x ═ fl, fr, rl, rr;

in the above formula (9), M_x(x∈[flfrrlrr]) Representing the sprung mass of each suspension of the vehicle, including the left front sprung mass M_flRight front sprung mass M_frLeft rear sprung mass M_rlRight rear sprung mass M_rr；m_x(x∈[flfrrlrr]) Indicating the unsprung mass of each suspension, including the left front unsprung mass m_flRight front unsprung mass m_frLeft rear unsprung mass m_rlRight rear unsprung mass m_rr；k_s-x(x∈[flfrrlrr]Showing spring rates of the respective suspensions, including a left front spring k_s-flRight front spring k_s-frLeft rear spring k_s-rlRight rear spring k_s-rr；k_t-x(x∈[flfrrlrr]) Representing the stiffness of each tire, including the left front tire k_t-flRight front tire k_t-frLeft rear tire k_t-rlRight rear tire k_t-rr；z_x(x∈[flfrrlrr]) Representing the displacement of the vehicle body at each suspension; z_t-x(x∈[flfrrlrr]) Indicating the displacement of each tire; z_r-x(x∈[flfrrlrr]) Representing road surface input at each wheel.A vibration acceleration representing a sprung mass of each suspension, which is directly measured by an acceleration sensor disposed on the vehicle body; z is a radical of_b-x-z_t-xThe displacement sensor can directly measure the relative displacement of the wheels relative to the vehicle body;the representation of the actuating speed of each shock absorber can be obtained by differentiating the signal of the position displacement sensor between the springs. α is a frequency (circular frequency) switching coefficient, which may be generally selected to be 20rad/s, and may also be calibrated according to a real vehicle; when in useWhen the frequency observer observes that the circular frequency is greater than alpha, the acceleration control is switched, otherwise, the double-state damping control is switched, and better performance is ensured in both a low frequency band and a high frequency band; c_d-x(x∈[flfrrlrr]) The damping target value is vertically controlled.

In one embodiment, the method further comprises: and finding out a current value corresponding to the final output damping value from the damping value and current mapping table, and controlling the currents in the left front damping controllable shock absorber, the right front damping controllable shock absorber, the left rear damping controllable shock absorber and the right rear damping controllable shock absorber according to the current value.

And obtaining a finally calculated output damping value, finding a corresponding current value through a mapping relation because the damping and the current are in a direct proportion relation, and controlling the currents in the left front damping controllable shock absorber, the right front damping controllable shock absorber, the left rear damping controllable shock absorber and the right rear damping controllable shock absorber according to the current value so as to realize the control of the vehicle.

Referring to fig. 5, in one embodiment, a method for integrated control of a semi-active suspension system of a whole vehicle is provided, which includes:

obtaining a vehicle speed V_VTurning speed V of steering wheel_steerLateral acceleration a_latAnd the accelerator pedal opening change rate V_pedalAcc/brake pedal opening change rate V_pedalB, longitudinal acceleration a_lonEqual signals;

lateral motion control decision start: judging the steering wheel angular velocity V_steerOr lateral acceleration a_latWhether the damping gradient is in a control damping gradient interval 1-control damping gradient interval N (lateral control damping gradient interval), if so, controlling the MAP laterally and presetting an output damping gradient interval 1-interval N;

judging the current vehicle speed V_VWhether or not it is greater than vehicle speed threshold value V_{V_i-value}，i∈[1，n]If so, controlling the MAP laterally (laterally) to preset an output lateral control damping target value C_{lat_i}，i∈[1,n]；

And simultaneously judging the lateral motion control, starting the longitudinal motion control to judge: judging the opening degree change rate of the accelerator pedal and the opening degree change rate V of the brake pedal_pedalOr longitudinal acceleration a_lonWhether the damping gradient is in a threshold interval of the corresponding control parameter, namely an interval 1-a control damping gradient interval N (a longitudinal control damping gradient interval); if yes, longitudinally controlling and presetting a corresponding damping gradient interval 1-interval N;

judging the current vehicle speed V_VWhether or not it is greater than vehicle speed threshold value V_{V_i-value}，i∈[1，n]If yes, the longitudinal (pitching) control presets and outputs a longitudinal control damping target value C_{lon_i}，i∈[1，n]；

Coupling and outputting the lateral control damping target value and the longitudinal control damping target value by a larger value, and recording the larger value as a lateral longitudinal control damping target value;

C_{posture_ix},i∈[1，n],x∈[fl fr rl rr].

obtaining a vertical control damping target value C from a vertical control module_d-x,x∈[fl frrl rr]；

And the integrated coordination control module performs coordination control on the vertical control damping target value and the side longitudinal control damping target value.

The embodiment guarantees the comfort in real time, reasonably restrains the roll and pitch of the vehicle body, and accurately gives consideration to the control stability of the vehicle.

Referring to fig. 6, the present invention further provides a control system adopting the integrated control method for the semi-active suspension system of the entire vehicle, including:

the vertical control module, the lateral and longitudinal combined control module are connected with the integrated coordination control module;

the vertical control module outputs a vertical control damping target value by adopting a mode of a hybrid control model of 'skyhook-acceleration' of a semi-active suspension of an 1/4 vehicle;

the process of longitudinally controlling the damping target value at the output side of the lateral and longitudinal combined control module comprises the following steps:

acquiring lateral control vehicle parameters, longitudinal control vehicle parameters and current vehicle speed;

determining a lateral control vehicle parameter threshold interval in which lateral control vehicle parameters are positioned, determining a lateral control damping gradient interval according to a mapping data table of the lateral control vehicle parameter threshold interval and the damping gradient interval, acquiring a vehicle speed threshold corresponding to the lateral control damping gradient interval, and acquiring a lateral control damping target value according to a vehicle speed and damping mapping table if the current vehicle speed is greater than the vehicle speed threshold;

determining a longitudinal control vehicle parameter threshold interval in which a longitudinal control vehicle parameter is positioned, determining a longitudinal control damping gradient interval according to a mapping data table of the longitudinal control vehicle parameter threshold interval and the damping gradient interval, acquiring a vehicle speed threshold corresponding to the longitudinal control damping gradient interval, and acquiring a longitudinal control damping target value according to a vehicle speed and damping mapping table if the current vehicle speed is greater than the vehicle speed threshold;

taking the lateral control damping target value and the longitudinal control damping target value with a large value as a lateral longitudinal control damping target value;

the process of outputting the final output damping value by the integrated coordination control module is as follows: calculating the final output damping value of the shock absorber according to the acquired vertical control damping target value, the damping proportion value determined according to the road condition and the lateral longitudinal control damping target value:

and finally outputting a damping value which is the damping ratio value x side longitudinal control damping target value + (1-damping ratio value) x vertical control damping target value.

Optionally, a current value corresponding to the final output damping value is determined, and currents in the left front damping controllable shock absorber, the right front damping controllable shock absorber, the left rear damping controllable shock absorber and the right rear damping controllable shock absorber are controlled according to the current value.

The lateral and longitudinal combined control module adopts a method of controlling thresholds of layered gradient intervals: the longitudinal control predicts the acceleration or braking intention of a driver by using an accelerator pedal opening change rate or a brake pedal opening change rate or identifies the longitudinal motion (pitching) state of the vehicle by combining a longitudinal acceleration signal, and inhibits pitching motion as the target damping of the longitudinal motion control is output in anticipation through 'layering and gradient interval threshold + presetting MAP'; the lateral control predicts the steering intention of a driver by using a steering wheel turning speed signal or identifies the lateral motion state of the vehicle by combining a lateral acceleration signal, and lateral control damping is output by taking the roll motion as an expectation through 'layering and gradient interval threshold value + presetting MAP'. And when the vehicle has roll and pitch, coupling the output to the integrated coordination control module by adopting a larger value. After the integrated coordination control module identifies the road condition of the whole vehicle running, the integrated coordination control module carries out integrated decision on the output damping from the vertical control module and the lateral control and longitudinal control module, finally determines the damping target value output by each damping adjustable shock absorber, ensures the comfort in real time, reasonably inhibits the roll and pitch of the vehicle body, and accurately gives consideration to the control of the control stability of the vehicle in real time.

The foregoing is considered as illustrative only of the principles and preferred embodiments of the invention. It should be noted that, for those skilled in the art, several other modifications can be made on the basis of the principle of the present invention, and the protection scope of the present invention should be regarded.