Browse Topic: Chassis

Items (14,450)
This study focuses on the dynamic behavior and ride quality of three different modes of oil-gas interconnected suspension systems: fully interconnected mode, left-right interconnected mode, and independent mode. A multi-body dynamics model and a hydraulic model of the oil-gas suspension were established to evaluate the system's performance under various operating conditions. The research includes simulations of pitch and roll excitations, as well as ride comfort tests on different road surfaces, such as Class B roads and gravel roads. The analysis compares the effectiveness of the modes in suppressing pitch and roll movements and their impact on overall ride comfort. Results show that the independent mode outperforms the other two in minimizing roll, while the fully interconnected mode offers better pitch control but at the cost of reduced comfort. These findings provide valuable insights for the future design and optimization of oil-gas interconnected suspension systems, especially in
Xinrui, WangChen, ZixuanZhang, YunqingWu, Jinglai
As a distributed wire control brake system, the electro-mechanical brake (EMB) may face challenges due to the need to integrate the actuator in the limited space beside the wheel. During extended downhill braking, especially on wet roads with reduced adhesion, the EMB must operate at high intensity. The significant heat generated by friction can lead to thermal deformation of components, such as the lead screw, compromising braking stability. This paper focuses on pure electric light trucks and proposes a tandem composite braking method. This approach uses an eddy current retarder (ECR) or motor to provide basic braking torque, while the EMB supplies the dynamic portion of the braking torque, thereby alleviating the braking pressure on the EMB. First, a driver model, tire model, motor model, and braking models are developed based on the vehicle's longitudinal dynamics. In addition, the impact of various factors, such as rainfall intensity, road slope, ramp length and vehicle speed, on
Liu, WangZhang, YuXiao, HongbiaoShen, Leiming
This paper presents findings on the use of data from next-generation Tire Pressure Monitoring Systems (TPMS), for estimating key tire states such as leak rates, load, and location, which are crucial for tire-predictive maintenance applications. Next-generation TPMS sensors provide a cost-effective and energy-efficient solution suitable for large-scale deployments. Unlike traditional TPMS, which primarily monitor tire pressure, the next-generation TPMS used in this study includes an additional capability to measure the tire's centerline footprint length (FPL). This feature offers significant added value by providing comprehensive insights into tire wear, load, and auto-location. These enhanced functionalities enable more effective tire management and predictive maintenance. This study collected vehicle and tire data from a passenger car hatchback equipped with next-generation TPMS sensors mounted on the inner liner of the tire. The data was analyzed to propose vehicle-tire physics
Sharma, SparshSon, Roman
Path tracking is a key function of intelligent vehicles, which is the basis for the development and realization of advanced autonomous driving. However, the imprecision of the control model and external disturbances such as wind and sudden road conditions will affect the path tracking effect and even lead to accidents. This paper proposes an intelligent vehicle path tracking strategy based on Tube-MPC and data-driven stable region to enhance vehicle stability and path tracking performance in the presence of external interference. Using BP-NN combined with the state-of-the-art energy valley optimization algorithm, the five eigenvalues of the stable region of the vehicle β−β̇ phase plane are obtained, which are used as constraints for the Tube-MPC controller and converted into quadratic forms for easy calculation. In the calculation of Tube invariant sets, reachable sets are used instead of robust positive invariant sets to reduce the calculation. Simulation results demonstrates that the
Zhang, HaosenLi, YihangWu, Guangqiang
In order to manage the serious global environmental problems, the automobile industry is rapidly shifting to electric vehicles (EVs) which have a heavier weight and a more rearward weight distribution. To secure the handling and stability of such vehicles, understanding of the fundamental principles of vehicle dynamics is inevitable for designing their performance. Although vehicle dynamics primarily concerns planar motion, the accompanying roll motion also influences this planar motion as well as the driver's subjective evaluation. This roll motion has long been discussed through various parameter studies, and so on. However, there is very few research that treats vehicle sprung mass behavior as “vibration modes”, and this perspective has long been an unexplored area of vehicle dynamics. In this report, we propose a method to analytically extract the vibration modes of the sprung mass by applying modal analysis techniques to the governing equations of vehicle handling and stability
Kusaka, KaoruYuhara, Takahiro
The half vehicle spindle-coupled multi-axial input durability test has been broadly used in the laboratory to evaluate the fatigue performance of the vehicle chassis systems by automotive suppliers and OEMs. In the lab, the front or rear axle assembly is usually held by fixtures at the interfaces where it originally connects to the vehicle body. The fixture stiffness is vital for the laboratory test to best replicate the durability test in the field at a full vehicle level especially when the subframe of the front or rear axle is hard mounted to the vehicle body. In this work, a multi-flexible body dynamics (MFBD) model in Adams/Car was utilized to simulate a full vehicle field test over various road events (rough road, braking, steering). The wheel center loads were then used as inputs for the spindle coupled simulations of the front axle with a non-isolated subframe. Three types of fixtures including trimmed vehicle body, a rigid fixture with softer connections and a rigid fixture
Gao, JianghuaSmith, DerekZhang, XinYu, Xiao
The Autocycle is a style of vehicle that most often utilizes a reverse-tricycle design with two front wheels and a single rear wheel. Modern autocycles in the United States are often utilized in a recreational role. This work presents physical measurements of two modern autocycles for use in accident reconstruction and pursues a deeper understanding of the unique attributes and handling associated with these vehicles. Vehicles were used to measure physical properties and subjected to cornering tests presented herein, and the data is compared to that for a conventional automobile. Observations on tire scuff marks are made from cornering tests unique to these vehicles. Strengths and challenges with this type of vehicle design are presented for various use cases as compared to conventional automobiles. Data and knowledge from this study are published to aid accident reconstruction efforts.
Warner, WyattSwensen, GrantWarner, Mark
The Electro-Mechanical Brake (EMB) eliminates the traditional hydraulic pipeline arrangement through high-performance servo motor at the vehicles brake calipers. This provides a foundation for intelligent electric vehicles to achieve high-precision, fast response, and strong robustness in brake clamping force control. However, EMB faces some tricky nonlinear disturbances such as varying system stiffness disturbances, complex friction obstruction, etc., which leads to a decline in clamping force control performance. Therefore, this paper proposes a high-quality clamping force control for EMB considering nonlinear disturbances. First, we establish an EMB actuator model including the permanent magnet synchronous motor, mechanical transmission mechanism, and system stiffness characteristics. Next, the high-quality clamping force control strategy for EMB is designed. An outer-loop clamping force regulator is developed using Proportional-Integral-Derivative (PID) feedback control and
Zhao, HuiChaoChen, ZhigangLi, LunWang, ZhongshuoWu, JianChen, ZhichengZhu, Bing
Fatigue design is invariably of prior concern for the automotive industry, no matter of the evolution of the mobility market: at first because carmakers must stay compliant with general structural integrity requirements for reliability, notably applicable to the chassis system, then due to the endless competition for lightweighting in order to mitigate product costs and/or enhance vehicle efficiency. In the past, this key performance was often tackled by basic reference load cases, making use of the simplest signal content, e.g. sinus functions, to practice constant amplitude loads on test rigs and for computations, respectively. Nowadays, full time series coming from proving ground measurements, or any corresponding virtual road load data computations, may be applied to feed complex vehicle computations for virtual assessment and complex test facilities for final approval, under variable amplitude loads. In between, the concept of load spectra (i.e. distribution of amplitudes with
Facchinetti, Matteo LucaTjhung, TanaJaffre lng, SébastienDatta, SandipHayat lng, RomainGuo, Mingchao
To provide an affordable and practical platform for evaluating driving safety, this project developed and assessed 2 enhancements to an Unreal-based driving simulator to improve realism. The current setup uses a 6x6 military truck from the Epic Games store, driving through a pre-designed virtual world. To improve auditory realism, sound cues such as engine RPM, braking, and collision sounds were implemented through Unreal Engine's Blueprint system. Engine sounds were dynamically created by blending 3 distinct RPM-based sound clips, which increased in volume and complexity as vehicle speed rose. For haptic feedback, the road surface beneath each tire was detected, and Unreal Engine Blueprints generated steering wheel feedback signals proportional to road roughness. These modifications were straightforward to implement. They are described in detail so that others can implement them readily. A pilot study was conducted with 3 subjects, each driving a specific route composed of a straight
Duan, LingboXu, BoyuGreen, Paul
The current research landscape in path tracking control predominantly focuses on enhancing tracking accuracy, often overlooking the critical aspect of passenger comfort. To address this gap, we propose a novel path tracking control method that integrates vehicle stability indicators and road curvature variations to elevate passenger comfort. The core contributions are threefold: firstly, we conduct comprehensive vehicle dynamics modeling and analysis to identify key parameters that significantly impact ride comfort. By integrating human comfort metrics with vehicle maneuverability indices, we determine the optimal range of dynamics parameters for maximizing passenger comfort during driving. Secondly, inspired by human driving behavior, we design a path tracking controller that incorporates an anti-saturation algorithm to stabilize tracking errors and a curvature optimization algorithm to mimic human driving patterns, thereby enhancing comfort. Lastly, comparative simulations with two
Lu, JunZeng, DequanHu, YimingWang, XiaoliangLiu, DengchengJiang, Zhiqiang
A large-scale logistics transport vehicle composed of two skateboard chassis is investigated in this paper. This unmanned vehicle with dual-modular chassis (VDUC) is suitable for transporting varying size of goods. The two chassis can be used jointly or driving separately as needed, which enhancing the reconfigurability of transport vehicle. Considering the road environment uncertainty and the rollover safety problem associated with large transport vehicle, this paper proposes the path planning of VDUC using the Artificial Potential Field(APF)+Model Predictive Control(MPC) while incorporating the rollover stability index. Due to the independent operation of the two modular chassis, based on the hierarchical control approach, the path following controller of the two modular chassis are designed separately according to the vehicle’s planned path. Distributed model predictive control is applied to coordinate the front and rear modular chassis, so it can realize the path following for the
Liu, ZuyangShen, YanhuaWang, Kaidiwang, Haoshuai
This study analyzes feedback and control methods for road feel simulation in automotive steer-by-wire front steering systems based on bidirectional control. Unlike traditional road feel design methods, this research employs a force-direct feedback-position type bidirectional control structure for the SBW system. It explores the mechanism of road feel generation in Electric Power Steering systems and designs a road feel simulation algorithm based on bidirectional control. Compared to conventional methods, the force direct feedback-position type bidirectional control method enables faster and more stable simulation of road feel torque. In low-speed driving, this approach provides higher steering ease, while at high speeds, the driving stability is enhanced, and both scenarios achieve an improved road feel. In the research, a complete vehicle model is established in Simulink at first, followed by a co-simulation with CarSim. A magic formula tire model and a nonlinear two-degree-of-freedom
Wang, YuxuanZheng, HongyuKaku, ChuyoZong, Changfu
Two wheelers motorcycles are used for many purposes e.g. commuting from one place to another, long highway rides, racing and off-roading. Motorcycles which are used in off-road conditions require higher suspension strokes to absorb large oscillations due to terrain conditions. These motorcycles undergo jumps of varying heights and different vehicle orientations. In some of the dynamic situations front wheel may land on the ground before the rear and in other cases it may be vice versa. To make sure that the vehicle is durable enough to withstand loads in such operating conditions, vehicle drop test was developed in test lab where vehicle is dropped from predefined heights in both front & rear wheel landing conditions. Same test case is simulated in multibody dynamics to capture loads at important connections of the frame. This paper presents the correlation exercise carried out to validate MBD model and simulation process with test data captured during lab test. Accelerations at
Jain, Arvind KumarNirala, Deepak
Advanced driver assistance systems (ADASs) and driving automation system technologies have significantly increased the demand for research on vehicle-state recognition. However, despite its critical importance in ensuring accurate vehicle-state recognition, research on road-surface classification remains underdeveloped. Accurate road-surface classification and recognition would enable control systems to enhance decision-making robustness by cross-validating data from various sensors. Therefore, road-surface classification is an essential component of autonomous driving technologies. This paper proposes the use of tire–pavement interaction noise (TPIN) as a data source for road-surface classification. Traditional approaches predominantly rely on accelerometers and visual sensors. However, accelerometer signals have inherent limitations because they capture only surface profile properties and are often distorted by the resonant characteristics of the vehicle structure. Similarly, image
Yoon, YoungsamKim, HyungjooLee, Sang KwonLee, JaekilHwang, SungukKu, Sehwan
Electric vehicles (EVs) are particularly susceptible to high-frequency noise, with rubber eigenmodes significantly influencing these noise characteristics. Unlike internal combustion engine (ICE) vehicles, EVs experience pronounced variations in dynamic preload during torque rise, which are substantially higher. This dynamic preload variation can markedly impact the high-frequency behaviour of preloaded rubber bushings in their installed state. This study investigates the effects of preload and amplitude on the high-frequency dynamic performance of rubber bushings specifically designed for EV applications. These bushings are crucial for vibration isolation and noise reduction, with their role in noise, vibration, and harshness (NVH) management being more critical in EVs due to the absence of traditional engine noise. The experimental investigation examines how preload and excitation amplitude variations influence the dynamic stiffness, damping properties, and overall performance of
Hazra, SandipKhan, Arkadip Amitava
In this paper, the equivalent elliptic gauge pendulum model of liquid sloshing in tank is established, the pendulum dynamic equation of tank in non-inertial frame of reference is derived, and the dynamics model of tank transporter is constructed by force analysis of the whole vehicle. A liquid tank car model was built in TruckSim to study its dynamic response characteristics. Aiming at the problem that the coupling effect between liquid sloshiness in tank and tank car can easily affect the rolling stability of vehicle, the roll dynamics model of tank heavy vehicle is established based on the parameterized equivalent elliptic gauge single pendulum model, and the influence of different lateral acceleration and suspension system on the roll stability is studied. The results show that the coupling effect between the motion state of the tank car and the liquid slosh lengthens the oscillation period of the liquid slosh in the tank, and the amplitude of the load transfer rate of the tank car
Yukang, Guo
To address the challenges of complex operational simulation for Electric Vehicles (EVs) caused by spatial-temporal variations and driver behavior heterogeneity, this study introduces a dynamic operation simulation model that integrates both data-driven and physics-based principles, referred to as the Electric Vehicle-Dynamic Operation Simulation (EV-DOS) model. The physics-based component encompasses critical aspects such as the powertrain energy transfer module, heat transfer module, charge/discharge module, and battery state estimation module. The data-driven component derives key features and labels from second-by-second real-world vehicle driving status data and incorporates a Long Short-Term Memory (LSTM) network to develop a State-of-Health (SOH) prediction model for the EV power pack. This model framework combines the interpretability of physical modeling with the rapid simulation capabilities of data-driven techniques under dynamic operating conditions. Finally, this study
Jing, HaoHU, JianyaoOuyang, JianhengOu, Shiqi(Shawn)
Gray cast iron is a cost-effective engineering material widely used for heavy duty engine blocks and brake rotor discs in vehicles. Thermomechanical fatigue (TMF) frequently occurs during vehicle operation due to temperature fluctuations in brake rotors. To speed up the design of the component, design structurally sounding brake rotors, and prevent premature thermally induced cracking, it is critical to investigate TMF behavior of the gray cast iron. This study presents a series of fatigue tests, including isothermal low cycle fatigue (LCF) tests at temperatures up to 700°C, as well as in-phase (IP) and out-of-phase (OP) TMF tests across various temperature ranges. Because of the asymmetric behavior in tension and compression, creep behaviors in both tension and compression and oxidation are also studied. These behaviors are the key to enable simulation of thermally induced cracks in rotors.
Liu, YiLee, HeewookHess, DevinCoryell, Jason
In this paper, an incremental coordinated control method through anti-squat/lift/dive suspension is proposed based on and suited to a distributed drive electric vehicle with front and rear dual motors. The precise relationship between the suspension reaction force and the driving force of the wheel is derived as the control model through an in-depth analysis of the wheel motion and force. Through imposing the first-order dynamics, the proposed method not only provides the longitudinal speed control of the vehicle but also suppresses the longitudinal, vertical and pitch vibration of the vehicle. Simulation results show that the suspension reaction force formula derived in this paper is more suitable for dynamic conditions, and compared with the control method based on the simplified suspension anti-squat/lift/dive control model, the proposed method using the accurate control model has superior comprehensive control performance.
Feng, CongWu, GuangqiangYang, Yuchen
The improvement of heat dissipation performance of ventilated brake discs is vital to braking safety. Usually, the technical approaches shall be material optimization or structural improvement. In this paper, a simulation model of the heat transfer of brake discs is established using STAR-CCM+ software. Cast iron, aluminum metal matrix composite (Al-MMC), and carbon-ceramic composite materials (C-SiC) are compared. The results show that: Al-MMC has better thermal conductivity so that a more uniform temperature gradient distribution shall be formed; C-SiC has poorer heat capacity yet, according to previous studies, it has better thermal stability, which is the ability to ensure its friction factor under high-temperature condition; cast iron performs better with convective heat transfer rate, which enhances the heat transfer between the surface and surrounding flow field. Based on the results, this paper proposes four types of material combined brake discs using different friction
Wang, JiaruiJia, QingZhao, WentaoXia, ChaoYang, Zhigang
The paper provides a detailed analysis of the transmission system design under the single motor drive scheme, with a focus on the 2024 Formula SAE (FSAE). The selection of the motor type is determined based on race rules and battery box output power limits. In terms of transmission ratio design, this study takes into account the car's power, balancing acceleration ability and maximum speed to determine an optimal transmission ratio through theoretical calculations and empirical values. Furthermore, it explores how to optimize overall drive system performance by considering technical parameters, power requirements, economic considerations of each system assembly, and validates these findings through software simulations. Notably, significant improvements in reliability are achieved with the newly designed transmission system and wheel rim system while also proposing lightweighting methods for key components. We have carried out extensive verification in both simulation and real vehicle
Wang, LiuxinLi, ChengfengZhu, XiranLiu, Minmin
Optimal control of battery electric vehicle thermal management systems is essential for maximizi ng the driving range in extreme weather conditions. Vehicles equipped with advanced heating, ventilation and air-conditioning (HVAC) systems based on heat pumps with secondary coolant loops are more challenging to control due to actuator redundancy and increased thermal inertia. This paper presents the dynamic programming (DP)-based offline control trajectory optimization of heat pump-based HVAC aimed at maximizing thermal comfort and energy efficiency. Besides deriving benchmark results, the goal of trajectory optimization is to gain insights for practical hierarchical control strategy modifications to further improve real-time controllers’ performance. DP optimizes cabin inlet air temperature and flow rate to set the trade-off between thermal comfort and energy efficiency while considering the nonlinear dynamics and operating limits of HVAC system in addition to typically considered cabin
Cvok, IvanDeur, Josko
Roller bearings are used in many rotating power transmission systems in the automotive industry. During the assembly process of the power transmission system, some types of roller bearings (e.g., tapered roller bearings) require a compressive preload force. Those bearings' rolling resistance and lifespan strongly depend on the preload set during the installation process. Therefore, accurate preload setting can improve bearing efficiency, increase bearing lifespan, and reduce maintenance costs over the life of the vehicle. A new method for bearing preload measurement has shown potential for high accuracy and fast cycle time using the frequency response characteristics of the power transmission system. One open problem is the design of the production controller, which relies on a detailed sensitivity study of the system frequency response to changes in the bearing and system design parameters. Recently, an analytical model was developed for multi-row tapered roller bearings that includes
Gruzwalski, DavidMynderse, James
As a crucial component of highway freight systems, tractor semitrailer vehicles play a key role in the transportation industry. However, their complex vehicle structure can lead to significant lateral instability during emergency obstacle avoidance, posing challenges to the vehicle's dynamic stability and safety. To enhance the emergency obstacle avoidance lateral stability of tractor semitrailer vehicles, a direct yaw moment lateral stability control strategy based on differential driving/braking is proposed. First, a 3-degree-of-freedom ideal linear dynamic model of the tractor-semitrailer is established, and its accuracy is validated. Then, a lateral stability control strategy for emergency obstacle avoidance is proposed. The upper-layer controller employs an improved feedforward differential model-free adaptive control (IMFAC) method to track the target yaw rate and vehicle sideslip angle, while the lower-layer controller focuses on optimizing tire load rate. Additionally, a drive
Guo, ShaozhongDou, Jingyang
The automotive subframe, also referred to as a cradle, is a critical chassis structure that supports the engine/electric motor, transmission system, and suspension components. The design of a subframe requires specialized expertise and a thorough evaluation of performance, vehicle integration, mass, and manufacturability. Suspension attachments on the subframe are integral, linking the subframe to the wheels via suspension links, thus demanding high performance standards. The complexity of subframe design constraints presents considerable challenges in developing optimal concepts within compressed timelines. With the automotive industry shifting towards electric vehicles, development cycles have shortened significantly, necessitating the exploration of innovative methods to accelerate the design process. Consequently, AI-driven design tools have gained traction. This study introduces a novel AI model capable of swiftly redesigning subframe concepts based on user-defined raw concepts
Yang, JiongzhiSarkaria, BikramjitKumaraswamy, PrashanthKailkere Srinivas, Praveen
Virtual prototyping enables tires to be involved in automotive research and development (R&D) at an early stage, eliminating the trial-and-error process of physical tire samples and effectively reducing time and costs. Semi-empirical/empirical tire models are commonly used to evaluate vehicle-tire virtual mating. To parameterize these models, finite element (FE) simulations are necessary, involving combinations of sideslip, camber, and longitudinal slip under various loads. This paper identifies that when multiple inputs are combined, the FE simulation conditions become complex and numerous, presenting a significant challenge in virtual prototyping applications. Through an extensive analysis of more than ten tire prediction modeling methods and models in detail, this paper demonstrates the significant potential of tire prediction modeling in addressing this challenge. We begin with an overview of the current state of research in tire virtual prototyping, reviewing its application
Yin, HengfengSuo, YanruLu, DangXia, DanhuaMin, Haitao
This study presents a control co-design method that utilizes a bi-level optimization framework for parallel electric-hydraulic hybrid powertrains, specifically targeting heavy-duty vehicles like class 8 semi-trailer trucks. The primary objective is to minimize battery energy consumption, particularly under high torque demand at low speed, thereby extending both battery lifespan and vehicle driving range. The proposed method formulates a bi-level optimization problem to ensure global optimality in hydraulic energy storage sizing and the development of a high-level energy management strategy. Two nested loops are used: the outer loop applies a Genetic Algorithm (GA) to optimize key design parameters such as accumulator volume and pre-charged pressure, while the inner loop leverages Dynamic Programming (DP) to optimize the energy control strategy in an open-loop format without predefined structural constraints. Both loops use a single objective function, i.e. battery energy consumption
Taaghi, AmirhosseinYoon, Yongsoon
Along with the innovation of vehicle technology, the active steering system has an excellent effect on the prevention of uncontrolled steering events due to its significant advantage in optimising handling stability. Meanwhile, the safety boundary is an important judgement basis for the stable operation of the vehicle, and based on the safety boundary, the controller can help the driver to keep the vehicle in the stable region of the state space. In this paper, an active rear wheel steering model prediction controller is proposed based on the safety boundary to control the rear wheel steering angle to assist the front wheel steering, and constrain the actual cross-swing angular angular velocity and centre-of-mass lateral deflection angle of the vehicle within the safety boundary of the state space, so as to ensure the stable operation of the vehicle, and the main research contents are as follows: 1. Aiming at the problem that the linear two-degree-of-freedom model of the vehicle can't
Li, ZiyuZheng, HongyuKaku, ChuyoZhang, Yuzhou
Tractor-semitrailers play an important role in the transportation industry. However, global warming and the rapid advancement of energy technologies have driven the transformation of high-emission vehicles, such as tractor-semitrailers, to be powered by new energy sources in order to achieve goals related to energy conservation, emission reduction, and cost savings. By using the motor as the primary driving force, the energy recovered during braking or coasting can be converted into electricity and stored in the battery for later use. While much research has been conducted on braking control and energy recovery for passenger cars, there is limited research on tractor-semitrailers. Additionally, the jackknife is a critical factor to consider under high-speed conditions. To investigate the braking energy recovery of electric tractor-semitrailers, tire and motor models were developed based on the turning and braking conditions of such vehicles. Taking into account the load transfer effect
Chen, RunpingDuan, Yupeng
Adverse weather conditions such as rain and snow, as well as heavy load transportation, can cause varying degrees of damage to road surfaces, and untimely road maintenance often results in potholes. Perception sensors equipped on intelligent vehicles can identify road surface conditions in advance, allowing each wheel’s suspension to actively adjust based on the road information. This paper presents an active suspension control strategy based on road preview information, utilizing a newly designed dual-chamber active air suspension system. It addresses the issue of point cloud stratification caused by vehicle body vibrations in onboard LiDAR data. The point cloud is processed through segmentation, filtering, and registration to extract real-time road roughness information, which serves as preview information for the suspension control system. The MPC algorithm is applied to actively adjust the nonlinear stiffness and damping of the suspension’s dual-chamber air springs, enhancing
Dong, FuxinShen, YanhuaWang, KaidiLiu, ZuyangQian, Shuo
Hydro-pneumatic suspension is widely used due to its favorable nonlinear stiffness and damping characteristics. However, with the presence of parameter uncertainties and high nonlinearities in the hydro-pneumatic suspension system, the effectiveness of the controller is often suboptimal in practical applications. To mitigate the influence of these issues on the control performance, an adaptive sliding mode control method with an expanded state observer (ESO) is proposed. Firstly, a nonlinear mathematical model of hydro-pneumatic suspension, considering seal friction, is established based on the hydraulic principle and the knowledge of fluid mechanics. Secondly, the ESO is designed to estimate the total disturbance caused by the nonlinearities and uncertainties, and it is incorporated into the sliding mode control law, allowing the control law to adapt to the operating state of the suspension system in real time, which solves the effect of uncertainties and nonlinearities on the system
Niu, ChangshengLiu, XiaoangJia, XingGong, BoXu, Bo
Advancements in sensor technologies have led to increased interest in detecting and diagnosing “driver states”—collections of internal driver factors generally associated with negative driving performance, such as alcohol intoxication, cognitive load, stress, and fatigue. This is accomplished using imperfect behavioral and physiological indicators that are associated with those states. An example is the use of elevated heart rate variability, detected by a steering wheel sensor, as an indicator of frustration. Advances in sensor technologies, coupled with improvements in machine learning, have led to an increase in this research. However, a limitation is that it often excludes naturalistic driving environments, which may have conditions that affect detection. For example, reductions in visual scanning are often associated with cognitive load [1]; however, these reductions can also be related to novice driver inexperience [2] and alcohol intoxication [3]. Through our analysis of the
Seaman, SeanZhong, PeihanAngell, LindaDomeyer, JoshuaLenneman, John
Distributed electric vehicles, equipped with independent motors at each wheel, offer significant advantages in flexibility, torque distribution, and precise dynamic control. These features contribute to notable improvements in vehicle maneuverability and stability. To further elevate the overall performance of vehicles, particularly in terms of handling, stability, and comfort, this paper introduces an coordinated control strategies for longitudinal, lateral, and vertical motion of distributed electric vehicles. Firstly, a full-vehicle dynamics model is developed, encompassing interactions between longitudinal, lateral, and vertical forces, providing a robust framework for analyzing and understanding the intricate dynamic behaviors of the vehicle under various operating conditions. Secondly, a vehicle motion controller based on Model Predictive Control is designed. This controller employs a sophisticated multi-objective optimization algorithm to manage and coordinate several critical
Jia, JinchaoYue, YangSun, AoboLiu, Xiao-ang
The braking performance of newer anti-lock braking system (ABS) equipped vehicles on roads with varying wetness levels is not well studied. Two late-model ABS-equipped vehicles were used to perform ABS-engaged braking tests on dry and wet asphalt and concrete surfaces from which vehicle speed and deceleration as a function of time were calculated. Tests were initially conducted on a dry surface before a water truck distributed water onto the road to create a wet road condition. A continuous series of tests were then performed until the road dried and the cycle was repeated multiple times. Across all tests of both vehicles on both road surfaces, deceleration levels generally decreased when the road was wet and returned to dry levels only when less than 25% of the road surface remained wet. Also, wet deceleration levels were high compared to the historical values used for wet roads. These findings provide a useful and readily identifiable boundary between what can be considered a dry and
Miller, IanKing, DavidSiegmund, Gunter
To ensure the safety and stability of road traffic, autonomous vehicles must proactively avoid collisions with traffic participants when driving on public roads. Collision avoidance refers to the process by which autonomous vehicles detect and avoid static and dynamic obstacles on the road, ensuring safe navigation in complex traffic environments. To achieve effective obstacle avoidance, this paper proposes a CL-infoRRT planning algorithm. CL-infoRRT consists of two parts. The first part is the informed RRT algorithm for structured roads, which is used to plan the reference path for obstacle avoidance. The second part is a closed-loop simulation module that incorporates vehicle kinematics to smooth the planned obstacle avoidance reference path, resulting in an executable obstacle avoidance trajectory. To verify the effectiveness of the proposed method, four static obstacle test scenarios and four RRT comparison algorithms were designed. The implementation results show that all five
Wu, WeiLu, JunZeng, DequanYang, JinwenHu, YimingYu, QinWang, Xiaoliang
With the continuous advancement of automotive intelligence, new energy vehicles are becoming increasingly popular. These vehicles demand a steering system independent of the engine, offering better control and enhanced steering performance. The steer by wire (SBW) system, known for its high precision and fast response, fulfills these requirements by providing improved flexibility, stability, and comfort. Consequently, SBW systems have attracted significant attention in both research and application domains. As the mechanical structure of the steer-by-wire system is canceled, the road feel can not be directly transmitted to the steering wheel, and it is necessary to apply the road feel obtained according to the state of the vehicle or combined with the planning of the driving environment to the steering wheel through the road feel motor to complete the road feel simulation so that the driver can feel the feedback similar to that of the traditional steering vehicles, which can not only
Li, ShangZheng, HongyuKaku, Chuyo
This study investigates the influence of magnetorheological (MR) dampers in semi-active suspension systems (SASSs) on ride comfort, vehicle stability, and overall performance. Semi-active suspension systems achieve greater flexibility and efficacy by combining MR dampers with the advantages of active and passive suspension systems. The study aims to measure the benefits of MR dampers in improving ride comfort, vehicle stability, and overall system performance. The dynamic system model meets all required performance criteria. This study demonstrates that the proposed artificial intelligence approach, including a fuzzy neural networks proportional-integral-derivative (FNN-PID) controller, significantly enhances key performance criteria when tested under various road profiles. The control performance requirements in engineering systems are evaluated in the frequency and time domains. A quarter-car model with two degrees of freedom (2 DOF) was simulated using MATLAB/Simulink to assess the
M.Faragallah, MohamedMetered, HassanAbdelghany, M.A.Essam, Mahmoud A.
The problem of monitoring the parametric failures of a traction electric drive unit consisting of an inverter, a traction machine and a gearbox when interacting with a battery management system has been solved. The strategy for solving the problem is considered for an electric drive with three-phase synchronous and induction machines. The drive power elements perform electromechanical energy conversion with additional losses. The losses are caused by deviations of the element parameters from the nominal values during operation. Monitoring gradual failures by additional losses is adopted as a key concept of on-board diagnostics. Deviation monitoring places increased demands on the information support and accuracy of mathematical models of power elements. We take into account that the first harmonics of currents and voltages of a three-phase circuit are the dominant energy source, higher harmonics of PWM appear as harmonic losses, and mechanical losses in the rotor and gearbox can be
Smolin, VictorGladyshev, SergeyTopolskaya, Irina
Vehicle handling is significantly influenced by aerodynamic forces, which alter the normal load distribution across all four wheels, affecting vehicle stability. These forces, including lift, drag, and side forces, cause complex weight transfers and vary non-linearly with vehicle apparent velocity and orientation relative to wind direction. In this study, we simulate the vehicle traveling on a circular path with constant steering input, calculate the normal load on each tire using a weight transfer formula, calculate the effect of lift force on the vehicle on the front and rear, and calculate the vehicle dynamic relation at steady state because the frequency of change due to aerodynamic load is significantly less than that of the yaw rate response. The wind velocity vector is constant while the vehicle drives in a circle, so the apparent wind velocity relative to the car is cyclical. Our approach focuses on the interaction between two fundamental non-linearity’s: the nonlinear
Patil, HarshvardhanWilliams, Daniel
With the continuous development of automobile technology, vehicle handling performance and safety have become increasingly critical research areas. The active rear-wheel (ARW) steering system, a technology that significantly enhances vehicle dynamics and driving stability, has garnered widespread attention. By coordinating front-wheel steering with rear-wheel angle adjustments, ARW improves handling flexibility and stability, particularly during high-speed driving and under extreme conditions. Therefore, designing an efficient ARW control algorithm and optimizing its performance are vital to enhancing a vehicle's overall handling capability. This study delves into the control algorithm design and performance optimization of ARW. First, a comprehensive vehicle dynamics model is constructed to provide a solid theoretical basis for developing control algorithms. Next, optimal control theory is applied to regulate the rear-wheel steering angle, and an LQR control strategy with variable
Zhang, YiZheng, HongyuKaku, ChuyoZong, ChangfuZhang, Yuzhou
The main purpose of the semi-active hydraulic damper (SAHD) is for optimizing vehicle control to improve safety, comfort, and dynamics without compromising the ride or handling characteristics. The SAHD is equipped with a fast-reacting electro-hydraulic valve to achieve the real time adjustment of damping force. The electro-hydraulic valve discussed in this paper is based on a valve concept called “Pilot Control Valve (PCV)”. One of the methods for desired force characteristics is achieved by tuning the hydraulic area of the PCV. This paper describes a novel development of PCV for practical semi-active suspension system. The geometrical feature of the PCV in the damper (valve face area) is a main contributor to the resistance offered by the damper. The hydraulic force acting on the PCV significantly impacts the overall performance of SAHD. To quantify the reaction force of the valve before and after optimization under different valve displacements and hydraulic pressures were simulated
Chintala, ParameshHornby, Ryan
Many methods have been proposed to accurately compute a vehicle’s dynamic response in real-time. The semi-recursive method, which models using relative coordinates rather than dependent coordinates, has been proven to be real-time capable and sufficiently accurate for kinematics. However, not only kinematics but also the compliance characteristics of the suspension significantly impact a vehicle’s dynamic response. These compliance characteristics are mainly caused by bushings, which are installed at joints to reduce vibration and wear. As a result, using relative or joint coordinates fails to account for the effects of bushings, leading to a lack of compliance characteristics in suspension and vehicle models developed with the semi-recursive method. In this research, we propose a data-driven approach to model the compliance characteristics of a double wishbone suspension using the semi-recursive method. First, we create a kinematic double wishbone suspension model using both the semi
Zhang, HanwenDuan, YupengZhang, YunqingWu, Jinglai
FSAE is a competition designed to maximize car performance, in which the steering system is a key subsystem, and the steering system performance directly affects the cornering performance of the car. The driver relies on the steering system for effective handling, which is also crucial for cornering and achieving faster lap times. Therefore, while improving the performance of the steering system, it is crucial to match the vehicle design to the driver's habits. Traditionally, steering systems typically use an Ackermann rate between 0% and 100% to offset the slip angle caused by tire deformation, thus achieving the purpose of reducing tire wear. Calculations have shown that a 40-60% Ackermann rate provides a similar compensation effect with little difference in tire wear. The traditional steering design method also does not consider the driver's driving habits and feedback, which is not conducive to the improvement of the overall performance of the car. In FSAE's figure-of-eight loops
Wu, HailinLi, Mingyuan
Vehicle sideslip is a valuable measurement for ground vehicles in both passenger vehicle and racing contexts. At relevant speeds, the total vehicle sideslip, beta, can help drivers and engineers know how close to the limits of yaw stability a vehicle is during the driving maneuver. For production vehicles or racing contexts, this measurement can trigger Electronic Stability Control (ESC). For racing contexts, the method can be used for driver training to compare driver techniques and vehicle cornering performance. In a fleet context with Connected and Autonomous Vehicles (CAVS) any vehicle telemetry reporting large vehicle sideslip can indicate an emergency scenario. Traditionally, sideslip estimation methods involve expensive and complex sensors, often including precise inertial measurement units (IMUs) and dead reckoning, plus complicated sensor fusion techniques. Standard GPS measurements can provide Course Over Ground (COG) with quite high accuracy and, surprisingly, the most
Hannah, AndrewCompere, Marc
This paper presents a novel Dual-source Electro-Hydraulic Brake system (D-EHB) that incorporates a redundant braking module to enhance safety and reliability. The D-EHB is designed to address the critical issue of brake failure in vehicles, which can lead to severe accidents. The D-EHB system comprises two independent units: the Main Brake Unit (MBU) and the Redundant Brake Unit (RBU). Each unit has its own hydraulic power source. The MBU's hydraulic pressure is generated by a combination of a servo motor, ball screw, and servo piston, while the RBU has a simpler structure, with hydraulic pressure generated by a motor and plunger pump combination. Mathematical models for each component of the D-EHB have been developed and validated using AMESim. The mathematical models of each part were then combined to design a wheel cylinder hydraulic pressure estimation algorithm that can calculate the wheel cylinder pressure based on motor and valve output signals, making the system applicable to
Wang, WenqiangZhao, XuezhiShangguan, Wen-BinRen, Bingyu
Clamping force control in Electromechanical Brake (EMB) systems must overcome various nonlinear characteristics, such as motor distorted voltage, Back Electromotive Force (EMF), and actuator friction disturbances. Therefore, modeling and parameter identification of these nonlinearities are necessary. This paper first proposes a motor parameter identification method based on the mathematical model of a Permanent Magnet Synchronous Motor (PMSM). A combination of the Least Square Method and Particle Swarm Optimization (PSO) is used to stepwise identify both the electrical and mechanical parameters of the motor. The accuracy of the identified parameters is validated by comparing simulation results with test bench responses. The identified parameters are applied to design the motor Back EMF compensation module, the distorted voltage compensation module, and to tune the current loop parameters. Next, a lumped parameter friction model suitable for closed-loop clamping force control in EMB
Qiao, LeXiong, LuZhuo, GuirongShu, Qiang
Brake-by-wire systems have received more and more attention in the recent years, but a close look on the available systems shows, that they have not reached full by-wire level yet. Most systems are still using hydraulic connections between main cylinder and the brake calipers on at least one axle to ensure functional safety. Mostly, this is the front axle, since the front brakes have to convert more kinetic energy during braking manoeuvers. Electromechanical actuators are currently used for rear brakes in hybrid brake-by-wire applications solely, since a loss of the front brake calipers can lead to severe conditions and control loss of the vehicle during braking. Further, the higher mass of battery electric vehicles (BEVs) leads to much higher braking forces on both axles and to increased sizes of the electromechanical calipers. This article presents a concept for a brake-by-wire system for battery electric vehicles, which features electromechanical brake actuators on all corners and a
Heydrich, MariusLenz, MatthiasIvanov, ValentinStoev, JulianLecoutere, Johan
The speed-dependent steering assistance is a fundamental function in electric power steering (EPS) systems. However, excessive levels of steering assistance can result in system instability, causing steering oscillations that compromise steering safety. Consequently, ensuring steering stability has become a primary focus in EPS development. Currently, the design of stability compensators for speed-dependent steering assistance has primarily focused on achieving system stability, often neglecting the attenuation of the designed assist gain by the compensator. In this paper, a novel method for the design of stability compensators within speed-dependent steering assistance is presented, aimed at ensuring system stability while reducing the attenuation of the designed assist gain by the compensator. First, a dynamic model of the EPS system is established, incorporating system inertia and viscous damping. The frequency response characteristics of the EPS system are obtained through vehicle
Kong, YiWei, ZhengjunDuan, XiaochengShangguan, Wen-Bin
Under extreme driving conditions, such as emergency braking, rapid acceleration, and high-speed cornering, the tire, as the vehicle’s only direct connection to the road, plays a critical role in influencing dynamic performance and driving stability. Accurately predicting and tire longitudinal force under such combined slip conditions is key to improving vehicle control precision and ensuring driving safety. This study proposes a tire longitudinal force estimation strategy based on an intelligent tire system. The core of this system consists of three integrated PVDF (Polyvinylidene Fluoride) sensors embedded in the tire, which, due to their exceptional sensitivity, can precisely capture dynamic deformation information of the tire under varying conditions. This provides real-time, detailed data to better understand the complex interaction forces between the tire and the road. To study and validate the longitudinal force estimation model, the research team employed a high-precision indoor
Zhang, ZipengXu, NanTang, ZepengChen, Hong
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