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This paper presents an industrial application of analytical target cascading (ATC) for the optimal design of a multi-axle vehicle chassis system. First, dynamic models are established, including the vehicle vibration and handling model, hydro-pneumatic suspension (HPS), and type model. Meanwhile, more holistic evaluation indexes for ride and handling characteristics are derived. Then, the hierarchical optimization framework is established with ATC methodology, and the suspension parameters are optimized. Compared with the original smoothness index RMS values at different vehicle speeds, the maximum optimized values of vibration acceleration, wheel dynamic load, and suspension deflection are 8.42 %, 7.84 %, and 3.09 %, respectively. Besides, the maximum relative errors of the theoretical and simulation models' understeer gradient and lateral acceleration are 3.27 % and 1.76 %, respectively. Finally, ATC reduces the computational cost compared to the all-in-one (AiO) approach. Thus, this paper can provide a theoretical foundation and optimization strategy for the multi-axle vehicle chassis. [ABSTRACT FROM AUTHOR]

To solve the problem of poor handling and stability control effect of self-propelled high-clearance sprayer under low-speed operating conditions, a direct yaw moment control scheme of handling stability was proposed. The 7-degree-of-freedom vehicle model including Dugoff nonlinear tire model was established, and a vehicle torque controller was designed with longitudinal control and lateral control. The longitudinal control was used to drive the wheels according to the error between actual vehicle speed and expected vehicle speed, and the force was controlled by PID closed-loop control. The lateral control was mainly composed of sliding mode controller and torque distributor, which was used to make up for the lack of longitudinal control on the driving force control. Five wheel control schemes were designed to achieve direct yaw moment for the realization of lateral control torque. The quadratic rotation orthogonal combination test was designed by the direct yaw moment realization scheme with vehicle speed and load quality as factors. By the response surface method, Design Expert software was used to explore the relationship between three factors and optimization index of handling and stability of working vehicle after introducing the direct yaw moment. The simulation test results show that the vehicle torque controller can effectively improve the steering stability of vehicle, and by changing the control scheme of inner wheel, the optimization index reaches as high as 55.2% under the combination of working speed of 1.25 m·s -1 and load of 1 000 kg. [ABSTRACT FROM AUTHOR]

Aiming at the problem of trajectory tracking and handling stability of intelligent four hub-motor independent-drive electric vehicle at high speed, an integrated control strategy based on model predictive control (MPC) is proposed. Firstly, a kinematics preview model is established considering the adaptive change of preview distance with longitudinal vehicle speed. Secondly, combined with the proposed preview model and considering the vehicle dynamic characteristics, an upper level controller of MPC is created to track the lateral deviation, heading angle deviation, sideslip angle and yaw rate to obtain the optimal solution of front wheel angle and additional yaw moment, which realize the control of handling stability while ensuring the trajectory tracking accuracy at same time. Then considering the varying road adhesion and the influence of longitudinal slip at the four tires, a lower level controller composed of torque optimal control and sliding mode controller is designed to realize the optimal torque distribution of four hub motors. Finally, through the co-simulation of MATLAB / Simulink and CarSim and the hardware-in-the-loop experiment, it is verified that the proposed integrated control strategy can effectively improve the path tracking accuracy and ensure the vehicle handling stability at high speed. Compared with the general MPC strategy, who does not control the sideslip angle and yaw rate with no preview model, the cumulative lateral tracking error of the integrated control is reduced by 51.9% and 87.7% respectively. [ABSTRACT FROM AUTHOR]

In this article, a novel vibration control scheme of suspension systems is proposed. It combines the advantages of quasi-zero stiffness isolator, nonlinear energy sink absorber, and inerter. This proposed scheme can achieve low transmissibility, low amplitude, and low additional weight and resolve the conflict between riding comfort and handling stability. Strong nonlinear vibration equations of a quarter-vehicle suspension system are established. It also presents the detailed process of high-order harmonic approximation to obtain steady-state responses. Moreover, approximate solutions are validated by a numerical method. Furthermore, based on riding comfort and handling stability, the following four suspension systems are evaluated and compared, namely, 2-degree-of-freedom quarter-vehicle model, 2-degree-of-freedom quarter-vehicle with quasi-zero stiffness isolator, 2-degree-of-freedom quarter-vehicle with inerter-nonlinear energy sink absorber, and 2-degree-of-freedom quarter-vehicle integrated control scheme with quasi-zero stiffness and inerter-nonlinear energy sink. It is found that the integrated control scheme with quasi-zero stiffness and inerter-nonlinear energy sink can significantly improve the riding comfort and handling stability at the same time. In addition, the effects of system parameters are studied carefully. The results show that based on the reasonable design of the control system parameters, better riding comfort and handling stability can be obtained. In short, this article provides a theoretical basis for integrating quasi-zero stiffness isolators and inerter-nonlinear energy sink absorbers to improve the riding comfort and handling stability. [ABSTRACT FROM AUTHOR]

In order to improve steering and roll stability for a heavy vehicle, a novel MIMO (multi-input-multi-output) controller is proposed based on an AMFC theory. A vehicle model considering the lateral motion, yaw motion and roll motion is developed. The establishment of reference models, controlled models and iteration algorithm of the feed-back matrix are presented. The Newton iteration method is used to correct the feed-back matrix in the real time, and the ideal control signal is calculated by the integral feed-forward matrix. The state of controlled model can approach reference model to achieve an adaptive online update for the steering control parameters under the transient conditions. The proposed AMFC have a good improvement in reducing side-slip angle, yaw rate and roll angle. The simulation and HIL experiments demonstrate the effectiveness and reliability of the proposed controller in improving the yaw stability and thus preventing rollover when necessary. [ABSTRACT FROM AUTHOR]

In order to study the effect of front and rear anti-roll bar's stiffness on vehicle's handling stability, the structure and force of the anti-roll bar are analysed, and the vehicle's rolling model, simplified car motion model and multi-body dynamics model of a car are established. The influence of stiffness change of the anti-roll bar on understeer of the vehicle is studied by constant radius cornering simulation. In swept-sine steering input simulation, the influence of stiffness change of the anti-roll bar on the response indexes of swept-sine steering input simulation are studied, the rule of these indexes changing with stiffness of anti-roll bar is obtained. It is found at high frequencies, due to the damping effect of the system, the influence of stiffness change on yaw rate gain is opposite to that of low frequency. In step steer input simulation, the influence of stiffness change of anti-roll bar on lateral acceleration and transition time are studied. Finally, this paper matches the stiffness of front and rear anti-roll bars of the vehicle based on swept-sine steering input simulation. The results show that the handling stability of the vehicle becomes relatively better after the stiffness of the anti-roll bars is matched. [ABSTRACT FROM AUTHOR]

A novel control strategy is proposed for the autonomous vehicle equipped with the front and rear independent steering systems to enhance the capability of collision avoidance and improve path tracking and handling stability under critical maneuvers. The novel control system includes a path replanning controller, a path tracking controller, and a stability controller. The path replanning controller is designed to generate a collision-free trajectory by optimizing a cost function. The cost function can be updated quickly and iteratively, according to the dynamic fitting matrix and measurement signals. The path tracking controller and the stability controller with considering multi-constraints are designed to generate the steering angle of the front wheel and the rear wheel, respectively, which improve the ability of path tracking and handling stability of the autonomous vehicle under extreme conditions. The real-time effectiveness of the proposed control strategy is verified and evaluated in Hardware-in-the-loop (HIL) simulation environment. The function of collision avoidance of the control algorithm is verified in the scenario of the preset obstacle artificially on the globally planned path. The proposed control strategy, presents superior performance against two other control strategies based on model predictive control algorithm, and also exhibits satisfactory performance in terms of path tracking as well as handling stability of the autonomous vehicle. [ABSTRACT FROM AUTHOR]

In order to study the effect of front and rear anti-roll bar's stiffness on vehicle's handling stability, the structure and force of the anti-roll bar are analysed, and the vehicle's rolling model, simplified car motion model and multi-body dynamics model of a car are established. The influence of stiffness change of the anti-roll bar on understeer of the vehicle is studied by constant radius cornering simulation. In swept-sine steering input simulation, the influence of stiffness change of the anti-roll bar on the response indexes of swept-sine steering input simulation are studied, the rule of these indexes changing with stiffness of anti-roll bar is obtained. It is found at high frequencies, due to the damping effect of the system, the influence of stiffness change on yaw rate gain is opposite to that of low frequency. In step steer input simulation, the influence of stiffness change of anti-roll bar on lateral acceleration and transition time are studied. Finally, this paper matches the stiffness of front and rear anti-roll bars of the vehicle based on swept-sine steering input simulation. The results show that the handling stability of the vehicle becomes relatively better after the stiffness of the anti-roll bars is matched. [ABSTRACT FROM AUTHOR]

Semi-active charging suspension has been the highlight in the research of ride comfort, handling, and safety of road vehicles in real time. Adjustable damping shock absorber is the key part of semi-active suspension. Many studies are focused on the control and impacts of automotive ride comfort. However, few of them are about the relationship among the damping of adjustable damping shock absorber, handling stability, and safety. In this article, a full car model based on multi-body dynamics was built, including the steering system, front and rear suspensions, tire, driving controller, and road. And the model was verified by tests. Based on the co-simulation, a controller was built based on hybrid sensor network control. The hybrid network control principle was switched among comfort controller, stability controller, and safety controller, in accordance with working conditions. The design effectively improved ride comfort, handling stability, and driving safety. Finally, a rapid control prototype was built based on dSPACE to conduct a real vehicle test. By comparison of the time response diagram, the results on pulse input and S-shaped road indicate that handling stability and driving safety enter into the stable domain and negative effects are successfully suppressed. [ABSTRACT FROM AUTHOR]

Aiming al ihe problem of llie influence of llie anli-roll bar on llie handling stability of llie passenger car, the relationship between the anti-roll har and llie anti-rolling ability of the vehicle was studied. A simplified mathematical model of passenger car was proposed, and the relationship between llie roll angle of the vehicle and the stiffness of llie anli-roll bar was established. The influence of the stiffness of the anti-roll bar on the roll of the vehicle was obtained by analyzing the simplified mathematical model of a passenger car. Based on ADAMS, the vehicle model was established, and the influence of the anti-roll bar stiffness of the front axle/rear axle to die handling stability was obtained through llie lest and simulation under the two working conditions of intermediate position steering and steady stale rotation, file simulation results show that with the increase of the stiffness, llie roll angle of llie frame decreases nonlinearly, and the slope of llie roll angle curve decreases gradually. The simulation results indicate that the simulation results are consistent with the theoretical analysis results, and provides a theoretical basis for the stiffness design of anti-roll bars. [ABSTRACT FROM AUTHOR]

Anti-roll hydraulically interconnected suspension (HIS) due to its roll-vibration stiffness and damping performance has been studied and applied in passenger vehicles, buses, and tri-axle straight vehicles. However, very few investigations have been made on six-axle articulated vehicles with the HIS system. Moreover, rollover accidents involving articulated vehicles cause severe casualties, which have attracted wide attention in the vehicle safety field. This calls for a design of a new suspension control technique to improve the handling stability performance at a lower cost and with less energy consumption. This paper presents an anti-roll HIS system control technique to improve the handling stability of a six-axle tractor–semitrailer with nonlinear uncertain parameters. Firstly, the HIS model for leaf-spring suspension of a half semitrailer is established by means of the linear transfer matrix method. Secondly, the power spectral density function is analyzed to validate the obtained model, and equivalent stiffness and damping are computed using natural frequency. Thirdly, six-axle vehicle equations with the HIS model are established considering the equivalent stiffness and damping parameter as the medium. Finally, numerical simulation results are provided and compared with the original vehicle. Dynamic response of the proposed technique is assessed by analyzing roll stability, lateral stability, yaw stability, and articulation stability. The results show that the proposed control technique can effectively improve the handling performance of an articulated vehicle. [ABSTRACT FROM AUTHOR]

To investigate the stability of in-wheel motor electric vehicles (IWMEVs) under extreme conditions, a novel control strategy including active rear steering (ARS) mode and direct yaw moment control (DYC) mode is proposed in this paper, utilizing the adaptive dynamic neural network (ADNN) algorithm to make the most of the two control modes. Firstly, a three-degree of freedom nonlinear vehicle model as well as some subsystems is established. Then, a two-layer stability control strategy is put forward, where the upper-layer calculates the desired rear steering angle as well as the differential torque of the rear wheels and the lower-layer executes commands and returns relevant signals. Besides, a stability controller based on ADNN algorithm is designed in the upper-layer so as to take advantage of the two modes under extreme conditions. Next, the impacts of initial values of the connection weights on the ability of ADNN algorithm to train and learn are revealed. Consequently, the optimal initial values can be ascertained before the following simulations. Finally, the closed loop simulations of ARS and DYC are carried out under some extreme conditions such as high velocity and low adhesion coefficient roads, and the results indicate that compared with DYC's difficulty in playing its role, ARS mode can significantly improve the stability of IWMEVs even under extreme conditions. [ABSTRACT FROM AUTHOR]

In order to solve the contradiction between the control output and the control effect, especially in extreme conditions, this paper designs a H ∞ /extension controller based on active front steering system by introducing the extension control into H ∞ mixed sensitivity control about sensitivity function S/T problem. The proposed controller can transform the control information under the unstable domain into the eligible value range by using dependent degree to tune the control output. And ultimately, the combination of H ∞ norm and extension transformation extends the stable region of the system. The results of the simulation and vehicle test show that the proposed H ∞ /extension controller can effectively deal with the contradiction between the control effect and the control output under extreme condition, and achieve satisfactory control effect with the control output as small as possible under normal condition. [ABSTRACT FROM AUTHOR]

This paper studies the control strategy of handling stability using an FSAE distributed drive pure electric racing car and the direct yaw moment control. The proportional integral derivative (PID) controller, fuzzy logic controller, and the PID and fuzzy logic joint controller of the additional yaw moment decision models are also designed. Under the double lane change condition, the designed control strategies are simulated and compared. The results show that compared with no control and PID control alone, the proposed PID and fuzzy logic joint control strategy can significantly reduce the steady-state value and the extreme value of the yaw rate by 43.87% at most, and those of the side slip angle by 68.53% at most. The convergence rates of the two have increased, improving the handling stability of the vehicle. [ABSTRACT FROM AUTHOR]

To adjust the control parameters according to road levels and study the characteristics of suspension nonlinear parameters under different road levels， an algorithm was proposed based on cuckoo search optimization and road estimation. Firstly， a quarter nonlinear suspension model with nonlinear dampers and springs was created， which sprung mass acceleration and tire deflection were taken as the optimization objective and the current of nonlinear dampers was taken as the optimization variable. Then， a cuckoo search-based multi-objective optimization method was used to calculate the optimal control parameter， and a road estimation method was used to identify the road level to adaptively adjust the system performance according to road input. The simulation results showed that: 1) the road estimation and cuckoo search-based algorithm can adjust the control parameter adaptively according to road levels， and the proposed method can improve riding comfort when the tire keeps contacting the road surface; 2) compared with the particle swarm optimization(PSO)， the current calculated by cuckoo search can provide better suspension performances. [ABSTRACT FROM AUTHOR]

A new hydraulically interconnected inerter-spring-damper suspension (HIISDS) is developed to compensate for traditional passive suspension limitations, such as the imbalance of ride performance and handling stability. In this article, the structure and mechanism of the HIISDS system is briefly introduced at first, and compiled with hydraulically interconnected suspension (HIS) mode and hydraulic inerter-spring-damper (ISD) suspension mode. A vehicle dynamic model of HIISDS system is then derived through these two suspension modes by using Matlab/Simulink. Two different road excitations are used to validate the adaption of the two suspension modes. The effectiveness of HIISDS has been verified by simulation results, in which vehicle ride comfort and handling stability are effectively coordinated through the HIISDS model switch. Finally, an HIISDS suspension prototype is designed based on Simulink results, and test results reconfirm the partial performances of HIISDS modes effectively. [ABSTRACT FROM AUTHOR]

The handling stability of three-axle vehicle with dual-front-axle-steering system was influenced by steering angle ratio of front axle to middle axle. A differential equation with tire magic formula was established to describe the plane motion with two degrees of freedom of three-axle vehicle with dual-front-axle-steering system. The vehicle steady and transient responses on steering wheel angle step input were numerically simulated. The influences of steering angle ratio of front axle to middle axle on steady and transient responses of several vehicles with different wheelbase and position of mass center were contrasted. The change rules of yaw angular velocity gain, reaction time and overshoot with steering angle ratio of front axle to middle axle were acquired. The results show that the handling stability can be improved by changing the steering angle ratio of front axle to middle axle according to vehicle design parameters. [ABSTRACT FROM AUTHOR]

In this paper, a roll and pitch independently tuned hydraulically interconnected passive suspension is presented. Due to decoupling of vibration modes and the improved lateral and longitudinal stability, the stiffness of individual suspension spring can be reduced for improving ride comfort and road grip. A generalised 14 degree-of-freedom nonlinear vehicle model with anti-roll bars is established to investigate the vehicle ride and handling dynamic responses. The nonlinear fluidic model of the hydraulically interconnected suspension is developed and integrated with the full vehicle model to investigate the anti-roll and anti-pitch characteristics. Time domain analysis of the vehicle model with the proposed suspension is conducted under different road excitations and steering/braking manoeuvres. The dynamic responses are compared with conventional suspensions to demonstrate the potential of enhanced ride and handling performance. The results illustrate the model-decoupling property of the hydraulically interconnected system. The anti-roll and anti-pitch performance could be tuned independently by the interconnected systems. With the improved anti-roll and anti-pitch characteristics, the bounce stiffness and ride damping can be optimised for better ride comfort and tyre grip. [ABSTRACT FROM AUTHOR]

In order to obtain accurate estimation of the tire gripping state, a model on the interaction between the tire and the ground playing a key role in the driving stability and the security of vehicles was studied in this paper. Adopting the Brush Model of tire and considering the contact differences between the longitudinal slip and the lateral slip considered, an improved Brush Model of tire based on the compound slip theory was proposed for modeling the tire gripping state. The Brush Model is an important method to predict the force between the tire and the ground, and in this simplified tire model, the contact state between the tire and the road can be divided into the adhesion area and the slip area. The forces in the adhesion area come from the static friction between the tread of rigid carcass and the road, and the forces in the slip area come from the sliding friction between the tread and the road. The innovation of this article is to distinguish the friction types between the adhesion section and the slip section, and the friction coefficients between the longitudinal and the lateral. The tire's ability to grip is the critical factor of driving, braking, steering and other performances of the vehicle, which comes from the horizontal friction between the tire and the ground. Various active control technologies have been developed to improve the drivability and applied to the active safety system of commercial vehicles. Some experts have raised the protection function of the limit manipulation cases, which was applied into the active manipulation controller. The ratio of the horizontal force and the vertical force was defined as the adhesion coefficient to analyze vehicle adhesion state in some papers. However, it only reflected the change of tire gripping, but the sliding state (the dangerous degree of tire slipping) could not be predicted due to the less accurate model or the complex parameter structure. The state of tire gripping was determined by the horizontal adhesive force, the slipping force and the maximum rolling friction coefficient. In order to obtain standardized expression for gripping state, a simple cubic equation was derived by defining the composite sliding coefficient and a series of constant terms, and the interaction of the parameters on gripping state in the model was discussed, together with the relationship between the velocity and the maximum rolling friction coefficient. In the end, the proposed model was validated by repeating three "Double Lane Change" tests, the equipment in which consisted of speed sensor (DEWE-VGPSHS), fiber optic gyroscope (iVRU-C167), car centroid test platform (JT-16), steering angle tester (SFA-A-2004S), multifunction meter (TESTO 480) and data acquisition system (DEWE-43), and speed, acceleration, steering angle and displacement were measured. The test results showed that in the steering periods 1.8-2, 3.2-3.4, 4.4- 4.6 s, the gripping states were 0.54, 0.79 and 0.39, respectively, and the limit error values were 4%, 5.4% and 5.2%, respectively, compared with the analytical values, while in the straight driving, the limit error of gripping state was less than 2%, which indicates that this analytical model obtains the higher accuracy under the conditions of the lower gripping state or straight driving and provides a new way for the estimation of tire gripping state. The research gives some guiding principles for the study of vehicle handling and stability. [ABSTRACT FROM AUTHOR]

With the rapid development of FSAE, the speed of racing cars has increased year by year. As the main research content of racing cars, aerodynamics has received extensive attention from foreign teams. For racing cars, the aerodynamic force on the aerodynamic device ultimately acts on the tires through the transmission of the body and the suspension. When the wheel is subjected to the vertical load generated by the aerodynamic device, the ultimate adhesion capacity of the wheel is improved. Under changing conditions, racing wheels can withstand greater lateral and tangential forces. Therefore, the effects of aerodynamics have a more significant impact on handling stability. The FSAE racing car of Jilin University was taken as the research object, and this paper combines the wind tunnel test, the numerical simulation and the dynamics simulation of the racing system. The closed-loop design process of the aerodynamics of the FSAE racing car was established, and the joint study of aerodynamic characteristics and handling stability of racing car under different body attitudes was realized. Meanwhile, the FSAE car was made the modification of aerodynamic parameter on the basis of handling stability. The results show that, after the modification of the aerodynamic parameters, the critical speed of the car when cornering is increased, the maneuverability of the car is improved, the horoscope test time is reduced by 0.525 s, the downforce of the car is increased by 11.39%, the drag is reduced by 2.85% and the lift-to-drag ratio is increased by 14.70%. Moreover, the pitching moment is reduced by 82.34%, and the aerodynamic characteristics and aerodynamic efficiency of the racing car are obviously improved. On the basis of not changing the shape of the body and the aerodynamic kit, the car is put forward to shorten the running time of the car and improve the comprehensive performance of the car, so as to improve the performance of the car in the race. [ABSTRACT FROM AUTHOR]

With improving vehicle stability as objective, an in-wheel motors / hydraulic brake system combined-control strategy is designed for four-wheel motor driven vehicles. The controller adopts layered control structure : the upper layer applies sliding mode variable structure theory to obtain the generalized force, while the lower layer uses quadratic programming method to optimize torque distribution, with consideration of the position and speed constraints of actuators. A CARSIM / MATLAB co-simulation is conducted for algorithm verification. The results show that under critical conditions, vehicles without control or controlled only with in-wheel motors can not complete the simulated operation, while the vehicle with in-wheel motor / hydraulic brake system combined-control strategy can assure the handling stability of vehicle. [ABSTRACT FROM AUTHOR]

To improve the vehicle handling stability, a four-wheel steering (4WS) controller with yaw rate tracking is proposed in this paper. A driver/ vehicle closed-loop system is built based on the preview-follower theory to evaluate the system's manoeuvring performance. Next, the system driving on a double lane-change road and on a low adhesion road are simulated and compared with conventional front-wheel steering vehicle. The Fourier transform method is developed to analyse the dynamics of the closed-loop system in the frequency domain. The results show that the proposed 4WS vehicle has the preferred response characteristics of sideslip angle and yaw rate, and is robust regarding tire cornering stiffness, which guarantees the handling stability in emergency braking condition. [ABSTRACT FROM AUTHOR]

For enhancing the handling stability of three-axle vehicles in normal driving conditions, an optimal control strategy for all-wheel steering of three-axle vehicles is proposed with a concurrent consideration of both low and high speed steering performances. A linear 2 DOF model for three-axle vehicle with all-wheel steering is built, the vehicle control objective for both low and high speeds is worked out respectively, and corresponding desired vehicle models are established. By applying the state regulator theory of linear quadratic optimal control and u-sing a control technique of tracking desired models by feed-forward and state feedback, an optimal control system of all-wheel steering is designed. Finally, a simulation model for the control system is built with MATLAB/Simulink with its performance at different speeds simulated. The results show that the vehicle with optimal control of all-wheel steering can have the minimum steering radius at low speed, and can get a better stability at high speed with no further operational burden put on driver. [ABSTRACT FROM AUTHOR]

For designing rational planetary gear steering mechanism, firstly the working principle of steering mechanism and the influences of design parameters are analyzed. Then based on related theories of vehicle dynamics and four-wheel steering with a control strategy of zero sideslip angle at mass center as objective, the relationships between the rotation angles of front wheels and rear wheels in different steering conditions are analyzed, and the design parameters of steering mechanism are determined. Finally taking a vehicle as an example, a rational steering mechanism is designed, a virtual prototype model for that vehicle is set up, and a simulation on its handling stability performance is conducted. The results show that the planetary gear steering mechanism can greatly enhance the maneuverability of vehicle at low speed and the handling stability at high speed. [ABSTRACT FROM AUTHOR]

A dynamic model for a fire-extinguishing water tanker is built with software MSC Adams/Car, based on which simulation tests are conducted on its handling stability and ride comfort performances. An optimization is then performed on the stiffness and damping of front and rear suspensions on the base of simulation data. Finally by trading off the results of optimization, the optimum combination of suspension parameters, which can im-prove both handling stability and ride comfort, is selected and validated by simulation test again. [ABSTRACT FROM AUTHOR]

A vehicle model with active suspension system is built, and the LQG control algorithm is adopted with both road roughness and the roll moment of car body as disturbance signals of vehicle system, the optimal control force for vehicle steering operation is calculated. Then a co-simulation on the coordinated control of the ride comfort and handling stability of vehicle running on A-class road and C-class road is conducted with step and single-cycle sine wave inputs of steering wheel respectively. The results show that compared with passive suspension, the coordinated control strategy proposed for active suspension can enhance the handling stability of vehicle without impeding the improvement of ride comfort. [ABSTRACT FROM AUTHOR]

To solve the contradiction between handling stability and ride comfort of vehicles with interconnected air suspension system (IASS) and reduce the energy consumption of air suspension with adjustable spring stiffness, a coordinated control for dynamic performance was designed based on the logic of switching interconnection modes and game control for the damper. The control system consists of a switching controller for air suspension interconnection modes and a distribution controller for the damping force. The switching controller determines the optimal air suspension interconnection mode by calculating the vehicle dynamic performance index in real-time. The distribution controller achieves a distribution for optimal damping force based on an infinite time differential game. veDYNA software that is a vehicle dynamics analysis software based on MATLAB/Simulink was used to verify the algorithm, and the accuracy was verified by a bench test. Finally, the results show this coordinated system can significantly improve the ride comfort and restrain the pitching motion. Compared with traditional suspension, the vertical acceleration decreases by 18.32% and the dynamic stroke decreases by more than 10% under the straight condition; the vertical acceleration decreases by 12.24% and the roll angle decreases by 1.26% under the steering condition. [ABSTRACT FROM AUTHOR]