Stability Analysis Of Vehicle Research Articles

Preview-based terrain adaptive active suspension control strategy for heavy-duty trucks

This paper proposes a preview-based active suspension control method for heavy-duty trucks, where the vehicle front wheel terrain preview information is employed to improve the performance of the rear, focusing on enhancing the handling stability and vehicle smoothness. To begin with, the vehicle front wheel preview information is introduced to the half-vehicle model, and a state quantity is employed to calculate the time lag between front and rear for predicting the control input of the rear wheel. Secondly, based on the developed model, an [Formula: see text] controller is designed with the half-vehicle model based on the current stochastic linear optimal control combined with the preview controller, which provides more stable effect than the prior controllers by merging perceived ground information. Furthermore, an established seven-degree-of-freedom vehicle suspension model is utilized for the preview-based controller to govern the kinetic behavior of the heavy-duty truck, allowing for a more thorough analysis of operation smoothness and vehicle stability. At last, the vehicle comparison simulations are carried out, which indicates that the preview-based [Formula: see text] controller designed by inspecting the terrain preview information can straighten out the smoothness and safety of the heavy-duty truck more effectively in contrast with the LQG controller.

Research on a novel compliant mechanism applied in the vehicle side door latch and stability analysis via Lyapunov exponents

The functional reliability of the vehicle latch is very important and is determined by the internal mechanism’s motion stability. In this paper, a novel compliant mechanism constructed with a novel compliant joint is applied to the vehicle latch, and multiple mode motions of the mechanism realize the newly added electric power release function. The repeatability of mechanism trajectories and phase diagrams of several different periodic motions is creatively regarded as the stability of the compliant mechanism. In this compliant mechanism, the endpoint of the groove-coupler is chosen as a characteristic point and the compliant joint’s spring stiffness kT is taken as the key parameter to obtain trajectories and phase diagram. It is found that all cycle overlapping phase diagrams possess intuitively good repeatability, except in two locally specific regions. Then, Wolf’s numerical calculation method of Lyapunov exponents is utilized to analyze the motion stability of the compliant mechanism. An appropriate range (1.0–1.05 N mm/°) of the joint stiffness kT is obtained, satisfying the stability criterion. Finally, characteristic point trajectory and functional experiments with kT = 1 N mm/° are conducted to verify the motion stability of the compliant mechanism. The method of mechanism motion stability analysis by means of Lyapunov exponents can be applied to other under-actuated mechanisms.

Simulation and experimental study on the stability and comfortability of the wheelchair human system under uneven pavement.

With the improvement in the level of science and technology and the improvement of people's living standards, the functions of traditional manual wheelchairs have been unable to meet people's living needs. Therefore, traditional wheelchairs have been gradually replaced by smart wheelchairs. Compared with traditional wheelchairs, smart wheelchairs have the characteristics of light operation and faster speed. However, when driving on some complex road surfaces, the vibration generated by the bumps of the motorcycle will cause damage to the human body, so wheelchairs with good electric power and stability can better meet the needs of people and make up for their travel needs. Based on the traditional vehicle stability analysis method, the mathematical theory of roll stability and pitch stability of the wheelchair-human system was established. We built a multi-body dynamics model with human skeleton and joint stiffness based on the multi-body dynamics method. The functioning of the wheelchair-human system was simulated and analyzed on the ditch, step, and combined road. The acceleration and Euler angle changes of the human head, chest, and wheelchair truss position were obtained, and the data results were analyzed to evaluate the stability and comfort of the system. Finally, a wheelchair test platform was built, and the road driving test was carried out according to the simulation conditions to obtain the system acceleration and angle data during the driving process. The simulation analysis was compared to verify the accuracy of the multi-body dynamics method, and the stability and comfort of the system were evaluated.

Vehicle Stability Analysis by Zero Dynamics to Improve Control Performance

Good stability performance is a prerequisite for the motion of vehicles controlled either by a human driver with advanced driver-assistance systems or by highly automated driving systems. Hence, vehicle motion control has become the core technology for vehicles driving everywhere in all conditions. However, vehicles might start to skid or spin, i.e., lose motion stability, even if some vehicle motion controllers are active. This motivates our work with a twofold contribution. First, we show that there are zero dynamics when input–output linearization is used in controller design. By analyzing the behavior of the zero dynamics, we identify why and under what conditions the vehicle starts to slide sideways and then spins. Second, based on the analysis results, we propose a cooperative control scheme to improve the motion stability of vehicles. A linear combination of the yaw rate and the sideslip angle is used as the control output, and we discuss which linear combinations are appropriate. Finally, simulation results, including a hardware-in-the-loop simulation, and experimental results with a refitted DongFeng E70 vehicle are given to illustrate the effectiveness of our method.

Structural Stability Analysis of Underwater High-Speed Moving Vehicles in Supercavity Flow Velocity

The purpose of this paper is to analyze the structural stability of an underwater high-speed vehicle. The drag characteristics of a moving body moving at high speed in water were analyzed, and a stability analysis of the structure was performed by applying the non-conservative property according to the driven force in a rocket propulsion environment. To this end, the fluid characteristics that enable high-speed maneuvering in an underwater environment were described, and the structural stability was analyzed by simplifying modeling by increasing the resulting drag. In addition, for high-speed underwater movement, an analysis of the following force according to drag and axial load and the effect on structural stability was conducted by simplifying the structure attached to a specific location when a supercavitation occurs.

Numerical Analysis on Water-Exit Process of Submersible Aerial Vehicle under Different Launch Conditions

To study the influence of launch conditions and wave interference on the stability of submersible aerial vehicles at the water–air interface, a coupling model for water-exit motion of submersible aerial vehicles was established by using the RNG k-ε turbulence model and VOF method. The water-exit processes of submersible aerial vehicles under different initial inclination angles and velocities were numerically simulated and the effects of initial inclination angle and velocity on the water-exit motion of submersible aerial vehicles were obtained. Based on the response surface function theory, a mathematical model for the motion stability of submersible aerial vehicles at the water–air interface was established, so that the submersible aerial vehicle’s pitch angle and velocity at the end of vehicle’s water-exit process, corresponding to any initial inclination angle and velocity, can be solved. The deviation between the simulated calculation result and the established fitting function model result was 2.7%. The minimum water-exit velocity of submarine aerial vehicles should be greater than 10.8 m/s. The research provides technical support for the trans-media motion stability analysis and hydrodynamic performance design of the submersible aerial vehicle.

Vehicle Stability Analysis under Extreme Operating Conditions Based on LQR Control.

Under extreme working conditions such as high-speed driving on roads with a large road surface unevenness coefficient, turning on a road with a low road surface adhesion coefficient, and emergency acceleration and braking, a vehicle's stability deteriorates sharply and reduces ride comfort. There is extensive existing research on vehicle active suspension control, trajectory tracking, and control methods. However, most of these studies focus on conventional operating conditions, while vehicle stability analysis under extreme operating conditions is much less studied. In order to improve the stability of the whole vehicle under extreme operating conditions, this paper investigates the stability of a vehicle under extreme operating conditions based on linear quadratic regulator (LQR) control. First, a seven degrees of freedom (7-DOF) dynamics model of the whole vehicle is established based on the use of electromagnetic active suspension, and then an LQR controller of the electromagnetic active suspension is designed. A joint simulation platform incorporating MATLAB and CarSim was built, and the CarSim model is verified by real vehicle tests. Finally, the stability of the vehicle under four different ultimate operating conditions was analyzed. The simulation results show that the root mean square (RMS) values of body droop acceleration and pitch angle acceleration are improved by 57.48% and 28.81%, respectively, under high-speed driving conditions on Class C roads. Under the double-shift condition with a low adhesion coefficient, the RMS values of body droop acceleration, pitch acceleration, and roll angle acceleration are improved by 58.25%, 55.41%, and 31.39%, respectively. These results indicate that electromagnetic active suspension can significantly improve vehicle stability and reduce driving risk under extreme working conditions when combined with an LQR controller.

Lateral Stability Analysis of 4WID Electric Vehicle Based on Sliding Mode Control and Optimal Distribution Torque Strategy

In this paper, we propose a lateral stability control strategy for four-wheel independent drive (4WID) electric vehicles. The control strategy adopts a hierarchical structure. First, a seven-degree-of-freedom (7DOF) 4WID electric vehicle model is established. Then, the upper controller adopts the integral sliding mode control (ISMC) method to obtain the desired yaw moment by controlling both the yaw rate and the sideslip angle. A new sliding mode reaching law (NSMRL) is designed to reduce chattering and make state variables converge faster, and the superiority of NSMRL is verified by theoretical analysis. The lower controller proposes a new optimal allocation algorithm, which selects the tire utilization rate and the standard deviation coefficient of the tire utilization rate as the objective function. The safety performance of vehicle is improved, and the instability caused by the significant difference in the stability margin between the four wheels under extreme road conditions is avoided. Finally, a simulation is carried out to verify the effectiveness of the proposed control strategy under single-lane-change and J-turn maneuvers.

Modal parameters-based hunting stability analysis of high-speed railway vehicles considering full range of equivalent conicity

The balance of vehicle parameters to avoid both the carbody and bogie hunting instabilities existing at different stage of vehicle operation is a long-standing problem. However, most of the existing researches focus on a single form of hunting instability and only take specific value of equivalent conicity as the worst case of wheel-rail contact relationship. To face this challenging problem, this paper studies the hunting stability of high-speed railway vehicles from the perspective of modal parameters based linearized analysis. The root locus analysis is carried out first to observe the modal information and hunting stability. The continuous modal tracking method is exploited to understand the variation regularity of each mode under the speed parametric excitation, especially when the frequency coupling occurs. Two objective functions related to the minimal damping ratio are proposed to indicate the severity of carbody and bogie hunting instabilities, respectively. The proposed objective functions consider the full range of running speed and wheel-rail contact conicity during operation. Starting from the objective functions, the sensitive analysis and a vector evaluated genetic algorithm are implemented to optimize the suspension parameters. Finally, the optimal solution of the suspension parameters is obtained after a generation of 20. The research method presented in this paper deepens the understanding of hunting motion and improves the vehicle stability in a simple, efficient and effective way.

Cornering stiffness estimation using Levenberg–Marquardt approach

Study of vehicle dynamics aggregates possibilities to enhance performance, safety and reliability, such as the integration of control systems, usually requiring knowledge on vehicle's states and parameters. However, some critical values are difficult to measure or are not disclosed. For this reason, dynamics and stability analysis of six-wheeled vehicles are compromised, and available information on this matter is limited. In this context, this paper proposes the estimation of the cornering stiffness of a 6x6 vehicle by an inverse problem approach applying the Levenberg–Marquardt (LM) method. The algorithm required data from field experiments and from simulations of a vehicle model during a double-lane change manoeuvre developed using . Experimental and theoretical values for the vehicle yaw rate were combined through LM method for cornering stiffness estimation. The excellent agreement between measured and simulated yaw rate indicates that the proposed model and the estimated parameters properly represent the vehicle dynamics response.

Dutch-Roll Stability Analysis of an Air Mobility Vehicle Using Navier–Stokes Equations

Dutch-roll motions caused by sudden gusts are studied for a typical advanced air mobility vehicle. The selected configuration consists of a fuselage with high wing powered by lifting and pushing propellers. Flow is modeled using the Navier–Stokes equations. A procedure is developed to embed the Dutch-roll motion equations in an overset grid topology along with rotating blades. Results are validated with lifting line theory computations and experiments. A typical Dutch-roll stability scenario is demonstrated by time-accurately integrating trajectory equations with the flow equations. The present work extends the capabilities of the current Navier–Stokes solvers to design urban air taxi configurations.

Flight dynamics modeling and stability analysis of a tube-launched tandem wing aerial vehicle during the deploying process

During the subsequent deploying process after the launch, the vehicle experiences dramatic changes in geometry as well as aerodynamics, which cannot be ignored for the flight stability of the aircraft. The investigation on the flight dynamics modeling and stability analysis during the unsteady deploying process is of great significance for the flight control system design and the launch system design. The nonlinear multibody dynamic model of the vehicle, which mainly consists of the airframe and four wings, is established through the Newton–Euler method. Meanwhile, the unsteady vortex lattice method (VLM), which is suitable for tandem wing aircraft and combined with the viscosity effect in light of the strip theory, is proposed to calculate the aerodynamic loads of the vehicle during the deploying process. A series of simulations about the motion of the vehicle after the launch are calculated to analyze the effects of various parameters, including the deploying forms, the start-up time of the power system along with the launching parameters, on the stability of the aerial vehicle in the deployment process. As results indicated, a small difference in the deploying rates of wings and larger deploying rates of wings on the same side are beneficial to the stability of the vehicle during the deploying process. Additionally, it is advantageous to the pitching stability but not the lateral stability of the vehicle when the power system is started earlier. Besides, the attitude control strategy of the vehicle can be formulated in advance by analyzing the attitude of the vehicle with different launch parameters at the launching moment.

Efficiency of the simulation model of a light commercial vehicle

The paper describes the results of the efficiency analysis of the simulation model of light commercial vehicle GAZ GAZelle NEXT. The efficiency of the model is confirmed by comparing the results of field test and calculation studies of controllability. The model is built in the MSC ADAMS/Car software package. It accounts for the mass-inertial characteristics of sprung and unsprung masses; the model of the suspension system simulates the kinematics and elasto-kinematics of the suspension and steering control, as well as elastic and damping elements. The tire model simulates vertical stiffness and damping, the slip stiffness depends on the vertical load, the longitudinal slip coefficient and the lateral angle of tire relative to the contact surface. The assessment was made by comparing the data obtained experimentally and by calculation. The test is conducted using the Fishhook method applied by NHTS for the vehicle stability analysis. The resulting errors are analyzed based on relative and absolute error values. When analyzing lateral acceleration and yaw rate deviations, the mathematical statistical tools are employed: average deviation, dispersion, root-mean-square deviation. The discrepancy between the results and the deviation of the average values does not exceed 10%. Minor deviations and scatter of results shows the efficiency of the simulation model and that this model can be employed for simulating the curvilinear motion of light commercial vehicles and assessment of their controllability and stability characteristics.

Applied flight dynamics modeling and stability analysis of a nonlinear time-periodic mono-wing aerial vehicle

This paper presents fly-ability, trim-ability, stability, and control ability of a mono-wing aerial vehicle as an under-actuated multi-body system. A nonlinear mathematical model of this vehicle with translational and rotational movements is developed. Based on early simulations, a conceptual prototype of the mono-wing is initially designed and constructed. A comprehensive nonlinear simulation is then performed by modeling aerodynamic forces and moments using the Blade Element Momentum (BEM) theory. Modeling and simulation are validated against experimental data to satisfy research needs. Twenty-three efficient dynamic parameters of the mono-wing are studied in ninety-seven simulation scenarios. Robustness against external disturbances in various trim conditions is examined. Flight test experiments reveal not only fly-ability but also high attitude stability in hovering-climb flight despite the imprecise model. This vehicle has a complex dynamic behavior that urges precise identification to reach stable flight performance. The model helps to achieve a deeper understanding of the flight characteristics of such vehicles. Wing area and incidence angle, position vectors of the aerodynamic center and rotation center, and the moment of inertia tensors are identified to be the most significant parameters on the flight stability of this vehicle. It is observed that the mono-wing has multiple trim conditions and is robust against external disturbances regardless of the control surfaced deflection, the center of gravity position, or even the wing geometry, because of the rotational stability and aerodynamic performance. Moreover, it is found both by simulation and experiment that although this vehicle is not full-state controllable and observable, it can be stabilized and guided to follow the desired trajectory and perform complex flight maneuvers.

Analysis of vehicle stability when using two-post above-ground automotive lifts: Distribution of forces in arms

Vehicles falling off two-post above-ground (2PAG) lifts in garages is a fairly frequent occurrence. As knowledge about the determining factors of such falls is limited, this paper looks at the technical determinants influencing the static stability of lifting with a 2PAG lift. The forces at the support pads and the moments induced in the lift arms were measured according to different configurations. After consultation, the selected controlled factors in the experimental design were lift wear and tear, vehicle type, vehicle position, loading of vehicle and use of fall-arrest latches. Based on analysis of variance, it was concluded that the factors that have a significant influence on the distribution of forces at the support pads are (i)the “loading * vehicle” interaction, (ii)the “lift * vehicle” interaction and (iii)the use of fall-arrest “latches.” Test results show that a compact vehicle with a loaded trunk better distributes its weight over the four arms, whereas the force distribution is evenly spread out on the four arms for an empty pick-up vehicle. A worn lift will amplify the uneven force distribution in the four arms for a compact vehicle, but lift wear does not seem to have practical implications for the force distribution in the case of a pick-up. Asymmetrically positionned fall-arrest latches tended to place a greater load on the two arms next to the latches. Finally, excessive vertical and horizontal forces on an arm were found in some configurations. Preliminary recommandations concerning inspection, vehicule placement and loading were made in accordance with these results.

등가 대기 속도를 활용한 돌풍 하중에 따른 무인 항공기 고소작업대의 구조물 안전성 해석

등가 대기 속도를 활용한 돌풍 하중에 따른 무인 항공기 고소작업대의 구조물 안전성 해석

Enhanced Fuzzy Non-Linear Power Control Based BLDC Motor Drive for Electric Vehicle Stability Analysis

Enhanced Fuzzy Non-Linear Power Control Based BLDC Motor Drive for Electric Vehicle Stability Analysis

Reach on damping control and stability analysis of vehicle with double time-delay and five degrees of freedom

Suspension system is one of the important parts of a vehicle, which is used to buffer the impact of uneven road to the body and passengers, so the suspension system has an important impact on the safety and ride comfort of the vehicle. In order to improve the safety and comfort of passengers and vehicles, in this paper a five-degree-of-freedom half car model is established, and the uncertainty of the model and the time-delay of the control are considered. The dynamic response of vehicle body acceleration root mean square, passenger acceleration root mean square, displacement root mean square and vehicle body pitch acceleration root mean square are selected as optimization objectives. The time-delay control parameters are determined by chaos particle swarm optimization algorithm. The time-delay stability of the suspension control system is analyzed by frequency-domain scanning method to ensure the stability of the time-delay control system. Finally, by establishing the simulation model of the active suspension system with double time-delay feedback control, the response characteristics of the suspension system with double time-delay active feedback control to simple harmonic excitation and random excitation input are analyzed. The results show that under the premise of ensuring the system stability, the active suspension system with double time-delay feedback control has good and obvious controlling and damping effect on the body and seats.

Development in the modeling of rail vehicle system for the analysis of lateral stability

Lateral stability of railway vehicle is a crucial aspect for railway vehicles. Primary critical speed, secondary critical speed, L/V ratio are the few measures of stability of railway vehicle. This paper reviews the linear and non-linear lateral stability analysis of railway vehicle. Various models presented by researchers for the analysis of vehicle stability in the past fifty years have been discussed. The major challenges faced by rail vehicle researchers for the accurate analysis of system stability have been briefly summarized in this article. The crucial parameters which influence the vehicle stability have been discussed in this paper.

On dynamic characteristics and stability analysis of the ducted fan unmanned aerial vehicles

This article researches the improvement of dynamics stability of the ducted fan unmanned aerial vehicles by optimizing its mechanical–structure parameters. The instability phenomenon of ducted fan unmanned aerial vehicles takes place frequently due to the complicated airflow in near-earth space, which easily leads to the stability problems, such as out of control, shaking, and loss accuracy of command tracking. The dynamics equations mirror its dynamics characteristics, which are primarily influenced by the mechanical–structure parameters of the whole system. Based on this, the optimization of mechanical–structure parameters has a significant to improve the dynamics stability of the whole system. Therefore, this article uses the concept of Lyapunov exponents to build the quantification relationship between system’s mechanical–structure parameters and its motion stability to enhance its stability from viewpoint of mechanical–structural parameter design. The takeoff, landing, and hovering stage are respectively studied and the conclusions suggest that the optimization of mechanical–structure parameters can be used to promote dynamics stability.