Browse Topic: Vehicle handling

Items (482)

A Novel Method for Evaluation of Tyre Structural Durability Performance

2024-26-035801/16/2024

In a vehicle, tyre is a safety critical component and hence its structural durability performance is of paramount interest to the vehicle users. Therefore, ensuring durability performance is an essential criterion to prevent fatal accidents, unusual road delays, etc. Generally, tyre structural durability or endurance performance is ascertained in the indoor laboratory by freely rotating the tyre on a smooth steel road wheel. The tyre runs straight ahead at a fixed speed and load is applied incrementally till failure or pre-defined level (fixed load step or fixed running kilometer). Although the test conditions used in these type of tests take care of certain parameters but it requires inclusion of additional parameters to simulate more realistic tyre operational conditions. One such parameter is camber angle in a vehicle, which is kept non-zero values (positive or negative) to achieve desired vehicle handling performance. Further, the roadways are also having in-built camber to

Upadhyay, Arpit, Kumar, Satheesh, Garg, Raghav, Ray, Kanai Lal, Ghosh, Prasenjit, Mukhopadhyay, Rabindra

Experimental Analysis of Multi-Link Rigid Axle Suspension Camber Variation with Vehicle Load

2024-26-005401/16/2024

Increased popularity on SUV category in the market has led to high focus on performance attributes of SUVs. Considering higher weight & CoG for achieving handling performance target is always a challenge. Static Wheel Alignment parameters, especially Camber have shown significant contribution in Handling attributes of vehicle. This paper presents an experimental study on change in wheel camber under the influence of different vehicle loading conditions. In SUVs, generally wheel is subjected to large deflection from its high static loads which makes it quite difficult to maintain an ideal camber angle. Hence, it is important to analyze the camber angle variations under actual loading conditions. An in-house fixture is developed to emulate the actual vehicle loading conditions at rear wheel end. The multi-link rigid axle suspension with watt's link assembly is mounted on the chassis-frame which is rigidly fixed to ground and loads are achieved through hydraulic actuators at Wheels. Axle

Jani, Harshil, Rasal, Shraddhesh, Hussain, Inzamam, Asthana, Shivam, ahire, Manoj, Vellandi, Vikraman, Senniappan, Moorthy

Influence of Rear Suspension Local Stiffness on Full vehicle Ride & handling Performance

2024-26-006101/16/2024

One of the biggest challenges for automotive industry is with respect to material saving and to have control on cost of development and still meeting performance in each aspect. Stringent weight targets help industries to have good margin on component costs. In recent times we have seen vehicle underbody contribution to total vehicle is significant in range of 12% to 18%. Total weight directly impacts the range of electric vehicle which is a key metric for success from real-world usage point of view and customer appeal. Hence control on suspension and frame design for light weighting is prominent trend in industry, this leads to deterioration of suspension compliance as well as vehicle ride and handling performance. Sub-frame and knuckle play crucial role in definition of overall suspension stiffness. Present Study focusses on electric vehicle rear cradle design for weight saving with minimum reduction of stiffness. Understanding compliance which obtained from frame\cradle in vehicle

Asthana, Shivam, Rasal, Shraddhesh, Ganesh, Lingadalu, V, Jesse Daniel, Nidasosi, Basavraj, Ramkumar, J, NAYAK, Bhargav, M, Sudhan, Vellandi, Vikraman

Effect of Lift Axle suspension design on Heavy Commercial Vehicle Handling performance

2024-26-004901/16/2024

The cost of fuels used for automobile are rising in India on account of high global crude oil prices. The fuel cost constitutes major portion of total cost of operation for Heavy commercial vehicles. Hence, the trend is to carry the goods transport through higher payload capacity rigid trucks that offer lower transportation cost per unit of goods transported. This is driving the design of multi-axle heavy trucks that have lift axles. In addition, improved network of highways and road infrastructure is leading to increase in average operating speed of heavy commercial vehicles. It has made increased focus on occupant as well as road safety while designing the heavy trucks. The load carried by lift axles is equivalent to the steered axle or drive axle. Hence, the analysis of lift axle suspension from the point of view of vehicle handling and stability is essential. There are two basic kinds of lift axle designs used in heavy commercial vehicles: caster steered lift axle having single

Vichare, Chaitanya Ashok, Raval, Chetan, Patil, Sudhir

A comparative study of vehicle handling characteristics of commercial vehicle with innovative nonlinear stiffness mono-leaf suspension with parabolic spring suspension through simulation

2024-26-005701/16/2024

In recent years due to significant increased cost of raw material, fuel and energy, vehicle cost is increased. As vehicle cost is one of the major factors that attracts prospective buyers, it has created specific demand for low weight and low-cost components than traditional components with better performance to meet customer expectations. Suspension is one of the critical aggregates where lot of material is used and reduction in weight tends to give lot of cost benefit. As suspension system derives vehicle's handling performance, it has to be ensured that handling performance of vehicle is maintained the same or made better while reducing weight of the suspension. Advancements in simulation capabilities coupled with manufacturing technology has enabled development non-traditional leaf springs. One of such springs is mono-leaf spring without. This type of leaf spring provides advantages such as low weight and nonlinear stiffness. Hence, this type of spring can cater the need of soft

Pandhare, Vinay Ramakant, Tiwari, Chaitanya, Deore, Yogesh, Khandekar, Dhiraj

Assisted Steering Control for Distributed Drive Electric Vehicles Based on Combination of Driving and Braking

2023-01-701210/30/2023

This paper presents a low-speed assisted steering control approach for distributed drive electric vehicles. When the vehicle is driven at low speed, the braking of the inner-rear wheel is combined with differential drive to reduce the turning radius. A hierarchical control structure has been designed to achieve comprehensive control. The upper-level controller tracks the expected yaw rate and vehicle side-slip angle through a Linear Quadratic Regulator (LQR) algorithm. The desired yaw rate and vehicle side-slip angle are obtained according to the reference vehicle model, which can be regulated by the driver through the accelerator pedal. The lower-level controller uses a quadratic programming algorithm to distribute the yaw moment and driving moment to each wheel, aiming to minimize tire load rate variance. Simulation and real vehicle tests compare three steering modes: front-wheel steering only, front-wheel steering + differential drive assisted steering, and front-wheel steering

Wu, Dongmei, Wang, Cheng, Du, Changqing, Zhang, Yichao

Path planning strategy of Distributed-driven articulated vehicle considering steering energy consumption

2022-01-034903/29/2022

The over-actuated characteristic of distributed driving vehicle can be used to generate the yaw moment by the reasonable allocation of each wheel driving force, which can reduce the energy consumption in the process of vehicle handling. The dynamic model of articulated vehicle with the electric-hydraulic hybrid steering is established by integrating the differential steering of vehicle. In this paper, the dynamic programming method is used to study the energy consumption of articulated vehicle with electro-hydraulic hybrid steering, and the energy-saving effects under different operating conditions are compared and analyzed. And on this basis, the rule-based control steering strategy for the articulated vehicle is built which can be used on-line. The model of articulated vehicle is established based on ROS platform, and tentacle algorithm is used for path planning of articulated vehicles. The stability and handling energy consumption of the vehicle are calculated for each tentacle

Niu, Tianwei, Shen, Yanhua, Bin, Xu

Three-axle Bus Handling Dynamics Evaluation Index

2022-01-034103/29/2022

This paper evaluates the handling characteristics of three-axle bus by using the unique comprehensive vehicle handling evaluation index. With the theory of total variance, the generalized side-slip angle unified transfer function is introduced to derivate the evaluation indexes of reaction time, transition time, damping ratio and total variance considering the suspension roll steer and camber thrust. The three-axle bus suspension roll steer and camber thrust produces extra lateral force. The three-axle vehicle response degree following the step steer input is analyzed with the effect of suspension roll on three-axle bus by using the total variance approach. The vehicle designers could use this approach to get optimization design parameters of bus suspension. The unique total variance evaluation index considering the suspension roll steer is useful and could serve as an important tool for evaluating the effect of suspension roll on three-axle bus handling dynamics.

Bump steer and Brake steer optimization in steering linkages through TAGUCHI method DOE analysis

2021-26-007909/22/2021

Due to recent infrastructural development and emerging competitive automotive markets in India, there is seen a huge shift in customer’s demand and vehicle drivability pattern in commercial vehicle industry. Now apart from ensuring better vehicle durability and best in class tyre life and fuel mileage, a vehicle manufacturer also has to focus on other key attributes like driver’s safety and ride comfort. Thus, for ensuring enhanced drivability, key parameters for ensuring better vehicle handling includes optimization of bump steer and brake steer. Both bump steer and brake steer are vehicle’s undesirable phenomenon where a driver is forced to constantly make steering wheel correction in order to safely maneuver the vehicle in the desired path. Since both bump steer and brake steer are caused due to the interactions of several vehicle parameters such as – drop arm and steering arm hard point, suspension stiffness, suspension eye and shackle position, caster angle, draglink length etc

Chopra, Nitin, P, Mahadevan

Influence of Asymmetrical Design Parameter on Vehicle Pull During Brake Application

2021-26-035409/22/2021

Abstract: The steering system of commercial vehicle is asymmetrical to left side and right side, this causes vehicle pull during braking application. This directly affects the safety of the driver and vehicle ride & handling performance. In a similar way, the asymmetrical suspension parameter unintentionally set during vehicle assembly are also major contributors for creating a vehicle pull. After application of brake force, the tire contact patch creates a moment about the kingpin axis. However, this moment generated is different on left and right-side due to asymmetrical design parameters resulting in vehicle deviation from its intended path. A large deviation may lead to on road accidents. Some of the major factors which are responsible for the vehicle pulling phenomenon are the asymmetrical steering system compliance, asymmetrical suspension geometry, tire, braking system, road camber etc. The present work is useful to analyze the effect of change (left to right side) in the

Dethe, Sachin, Khandekar, Dhiraj, Dhawad, Ashwin, Tiwari, Chaitanya

Subjective and Objective Steering feel Evaluation of compact SUV electric power steering system using Hardware in the Loop Simulation

2021-26-008009/22/2021

Hardware-in-the-loop (HIL) test benches are indispensable for the development of modern vehicle dynamics controllers (VDCs). They can be regarded as a standard methodology today, because of the extremely safety critical nature of the multi-sensor and multi-actuator systems used in vehicle dynamics control. The required high quality standards can only be ensured by systematic testing within a virtual HIL environment before going into a real car. The steering system is an important aspect of the automobile from operational safety and driver enjoyment perspectives. Current Problem/Opportunity is realistic subjective steering feel prediction before vehicle build. And upfront predict the handling characteristics more accurately with subjective feel before proto build. Current Issue is difficult to convert the objective data into subjective feel and difficult to incorporate the nonlinear steering characteristics with hysterics, friction and power assist curves using virtual simulation

Anthonysamy, Baskar, TK, Sreeraj, TK, Sreedeep, N, BALARAMAKRISHNA, NAGARAJAN, NAGAPRAKASH

Suspension Components Calculation at Concept Stage to Evaluate the Ride and Handling Characteristics

2021-26-008209/22/2021

Vehicle handing and ride are the critical attributes for customers while buying new passenger vehicle. Hence it is very important to design suspension which meets customer expectations. Often tuning of suspension parameters is very difficult at later stage like wheelbase, vehicle center of Gravity and other suspension parameters like roll center heights etc. A parametric mathematical model is built to study the effect of these parameters of vehicle handling and ride attributes at concept stage. These models are used to calculate the suspension ride rates, spring rates and Anti roll bar diameters for meeting target vehicle ride and handling performance. The model also calculates natural frequency of suspension and vehicle for understanding pitch and roll behaviours. The inhouse tool developed is used for calculating suspension damper characteristics and predicts ride attributes like Bounce damping, bounce stiffness, Isolation level, Flat ride and Impact Hardness categorized based on

Saifee, Aliakbar, Deshmukh, Chandrakant, deole, Subodh

Letter from the Guest Editors

03/17/2021

Letter from the Guest Editors

Hamid, Umar Zakir Abdul, Sandblom, Fredrik, Habibovic, Azra, Li, Bin

Sliding Mode Controlled Half Car Suspension System with Magnetorheological Damper

2020-01-154006/03/2020

Attenuation of vibrations caused by the road undulance conditions are tedious and very much related to human health and vehicle handling problems. One of the promised approaches to solving these problems in a vehicle suspension system is the use of effective controllers. In this paper, the sliding mode controller (SMC) is designed and used to control the magnetorheological (MR) damper. The performance of the proposed controller is verified by incorporating the controller in a half car vehicle suspension model. In a suspension damper design, Modified Bouc-Wen model is used to characterize the hysteretic behaviour of MR damper parameters. The voltage control algorithm is used to convert the desired force into the varied voltage input to the MR damper. The fail-proof advantage of MR damper is analysed by comparing the results of uncontrolled MR suspension with a passive system. In order to limit the pitch angle and to achieve the improved ride comfort and stability of the vehicle, the

SOOSAIRAJ, AROCKIA SUTHAN, K, ARUNACHALAM

Study on Impact of SUV chassis stiffness on vehicle dynamics through CAE

2020-01-100404/14/2020

Now a day’s automotive industry is a highly competitive market where continuous innovation in design and production of vehicles is required to gain market share and survive in the market. This resulted in the reduction of the life cycle of the design process and design tools. Identifying, understanding and refining these details is significant to develop sustainable cars. Body and Chassis stiffness are important specifications of a passenger car which affects handling, steering and ride characteristics of the vehicle. It has been proved that torsional, lateral and local chassis stiffness can play a role in giving the customer a premium feeling by affecting key metrics in the vehicle dynamics behaviour of a passenger car. In this paper, the effect of chassis stiffness on vehicle dynamics performance is studied using CAE. Different attributes of vehicle dynamics like vehicle handling, On-Center feel and vehicle ride are considered as performance characteristics. The chassis stiffness is

Lenka, Visweswara, Anthonysamy, Baskar, N, BALARAMAKRISHNA, Londhe, Abhijit

Study of Tire contribution to Vehicle Noise, Ride and Handling performance using DOE (Design of Experiments) Techniques.

2020-01-123804/14/2020

Automotive Industry has always kept the customer in focus and strived for their delight using innovative technologies and meticulous engineering. From a vehicle dynamics point of view, the customer’s performance expectations have diversified over the last decade. To meet these expectations, there have been significant developments in the system and subsystem engineering of chassis elements. One such contributing element is the tire as it can synergize with vehicle noise, ride and handling performance irrespective of propulsion energies. These critical customer touchpoints, they need to be optimized and tuned to meet stringent OEM targets. The objective of this paper is to understand the aspects of tire design, structure and tread compound on vehicle noise, ride and handling performance using a full factorial DOE (Design of Experiment) approach. The traditional iterative method of tire tuning is time-intensive and cannot quantify the interdependence within the tire. Since tire

Thomas, Juban, Kirtane, Kaustubh, Cherian, Thomas, Sanghani, Rahul R., Loganathan, Subramaniam, Suhalka, Kamal

A Smart Measuring System for Vehicle Dynamics Testing

2020-01-106604/14/2020

A fast measurement of the car handling performance is highly desirable to easily compare and assess different car setup, e.g. tires size and supplier, suspension settings, etc. Instead of the expensive professional equipment normally used by car manufacturers for vehicle testing, the authors propose a low-cost solution that is nevertheless accurate enough for comparative evaluations. The paper presents a novel measuring system for vehicle dynamics analysis, which is based uniquely on the sensors embedded in a smartphone and therefore completely independent on the signals available through vehicle CAN bus. Data from tri-axial accelerometer, gyroscope, GPS and camera are jointly used to compute the typical quantities analyzed in vehicle dynamics applications. In addition to signals such as yaw rate, lateral and longitudinal acceleration, vehicle speed and trajectory, normally available when working with Inertial Measurement Units (IMU) equipped with GPS, in the presented application the

Galvagno, Enrico, Mauro, Stefano, Pastorelli, Stefano, Tota, Antonio

New Integrated Vehicle Dynamics Control System Based on the Coordination of AFS, DYC, and ED for Improvements in Vehicle Handling and Stability

10-04-02-000901/27/2020

An integrated vehicle dynamics control system aiming to improve vehicle handling and stability by coordinating active front steering (AFS), direct yaw control (DYC), and electric differential system is developed in this article. First, an electric differential system for electric vehicle, composed of two sets of bi-PMS, in-wheel motors connected in parallel and supplied by a single five-leg inverter, one on the front axle and one on the rear axle, is designed. However, each set is controlled by a proposed sliding mode backstepping control, which has replaced the hysteresis controllers in the conventional direct torque control (DTC), can obviously reduce the torque ripple, and provide better speed tracking performance using sliding mode speed controllers. Second, an integrated control system which coordinates AFS and DYC braking system is designed by using a stability index, based on stability domain in the phase plane portrait, and a gain scheduling parameter to improve vehicle

Aouadj, Norediene, Hartani, Kada, Fatiha, Mekri

Evaluating Effects of Roll Stiffness Change at Front and Rear Axles on Vehicle Maneuverability and Stability

2019-28-240611/21/2019

To cater the push towards “Vehicle Light Weighting”, both sprung and unsprung mass are being reduced. This results in reduced stiffness and thus has a profound undesirable effect on the overall vehicle handling. To understand the effect of different reduction ratios of sprung to unsprung mass; it is desired to understand how changes in stiffness affect the overall vehicle handling characteristics. Therefore, the study was conducted to experiment with different values of roll stiffness, at both front and rear axles and comparing the frequency response and phase change of Yaw Gain observed through a Pulse Input test. The present work is further correlated with subjective feedback to predict the shift in vehicle balance and handling characteristics.

Reuben, Eric Pranesh, Budhiraja, Raghav, N, Sreeraj, K, Rakesh, Singh, Amardeep

Axle Torque Distribution to Improve Vehicle Handling and Stability

2019-01-503711/04/2019

The majority of the fully electric vehicles currently on the market have a basic drivetrain configuration, consisting of multiple electric motors, which promise considerable performance enhancements in terms of vehicle behavior and active safety. A significant advantage was achieving measurable benefits in terms of vehicle cornering response through controlling the individual drivetrains. This paper presents an axle torque distribution method to improve a 4WD vehicle steering performance. The method can automatically adjust the output drive torque of the front and rear motors of the vehicle to change the vehicle yaw rate before ESP intervention, and at the same time remain the driver torque demand unchanged. In this paper we present a feedback yaw rate controller. When the estimated yaw rate differs from the actual yaw rate with a pre-defined small threshold, a yaw rate control is active, the purpose of the controller is to reduce the vehicle understeer characteristic. The simulation

Wu, Aibin, Li, Chao, Zhao, Yongqiang, Cui, Jinlong

A Heavy Tractor Semi-Trailer Stability Control Strategy Based on Electronic Pneumatic Braking System HIL Test

10-03-03-001610/15/2019

Aiming to improve the handling performance of heavy tractor semi-trailer during turning or changing lanes at high speed, a hierarchical structure controller is proposed and a hardware-in-the-loop (HIL) test bench of the electronic pneumatic braking system is developed to validate the proposed controller. In the upper controller, a Kalman filter observer based on the heavy tractor semi-trailer dynamic model is used to estimate the yaw rates and sideslip angles of the tractor and trailer. Simultaneously, a sliding mode direct yaw moment controller is developed, which takes the estimated yaw rates and sideslip angles and the reference values calculated by the three-degrees-of-freedom dynamic model of the heavy tractor semi-trailer as the control inputs. In the lower controller, the additional yaw moments of tractor and trailer are transformed into corresponding wheel braking forces according to the current steering characteristics. The HIL test bench of the electronic pneumatic braking

Zheng, Hongyu, Miao, Yangyang, Li, Bin

Considerations for Suspension Modification

J2492_201910 (Current)10/09/2019

The scope of this document is limited specifically to the following types of passenger vehicles: automobiles, light trucks, and sport/utility vehicles. This document addresses modifications as they apply to legal use of the vehicle, and examines suspension modification as it applies to stock (as manufactured) ride height, and changed (raised or lowered) ride height. Note that modifications of ride height are considered, exclusive of wheel and/or tire modifications, which can also have potentially serious side effects, and are outside the scope of this document.

Motor Vehicle Council

A Dictionary of Terms for the Dynamics and Handling of Single Track Vehicles (Motorcycles, Scooters, Mopeds, and Bicycles)

J1451_201909 (Current)09/24/2019

Terminology within this document is limited to the dynamics and handling characteristics of single track, two-wheeled vehicles.

Motorcycle Technical Steering Committee

Application of Optimal Control Method to Path Tracking Problem of Vehicle

10-03-03-001408/26/2019

Path tracking is an essential stage for vehicle safety control. It is more newsworthy than ever in the automotive context and especially for autonomous vehicle. The study proposes an optimal control method for path tracking problem in inverse vehicle handling dynamics. The proposed method generates an expected trajectory which guarantees minimum clearance to the prescribed path by identifying the optimal steering torque input. Based on this purpose, the path tracking problem, which is treated as an optimal control problem, is then solved by local collocation method and mesh refinement. Finally, a real vehicle test is executed to verify the rationality of the proposed model and methodology. The results show that using control variables as a mesh refinement function can capture the dramatic changes in state variables, and the efficiency improvement is more significant as the number of the grid points increases. The study can help drivers easily identify safe lane-keeping trajectories and

Liu, Yingjie, Cui, Dawei

Robust Model Predictive Control for Path Tracking of Autonomous Vehicle

2019-01-069304/02/2019

Path tracking is one of the critical technologies in the autonomous vehicle. Its performance may be seriously affected by disturbance resulting from unpredictable environment like changes in road friction coefficient and parameter uncertainty such as cornering stiffness and mass caused by errors of measurement. Besides, since the vehicle system consisting of many systems is an extremely complex nonlinear system, it is almost impossible for us to establish a precise model of a vehicle especially when it is moving. These inevitable factors influence the control accuracy and even threaten the stability and safety of the vehicle system. This paper proposed a promising solution to this problem, robust MPC (Model Predictive Control) combined with the optimal preview controller for path tracking problems of an autonomous vehicle. The state space model in tracking error variables of a passenger vehicle used for path tracking application is established. In order not to regard road curvature as

Yu, Jiaxing, Guo, Xuexun, Pei, Xiaofei, Chen, Zhenfu, Zhu, Maolin, Gong, Bian

Measuring the Displacement of a Vehicle Body with an Optical Measuring System (Motion Capture)

2019-01-039304/02/2019

The 3D measurement of a body displacement on a moving vehicle is a quite challenging process. Well-known displacement measuring device such as a dial gauge and strain gauge can measure the displacement in only limited areas. An accelerometer also can estimate body motion but it has an accumulated error and a bias issue for an acquisition of displacements. However, an optical measuring (Motion Capture) method which uses markers and multiple cameras can read 3D coordinates directly and carry out those measurements well. In this paper, first, we determined how to extract a body displacement from global motion. Then we suggested a combining measurement methodology which uses a motion capture and an accelerometer simultaneously. Though it has failed to compensate each result and exact displacement, we showed an accuracy comparison between a motion capture and an accelerometer to measure a displacement along this process. Next we verified the measuring error of the motion capture and

Hur, Jung Woo, Ahn, Joong Jei, Oh, Joo Tae

Rear-Wheel Steering Control for Enhanced Maneuverability of Vehicles

2019-01-123804/02/2019

This paper proposes a rear-wheel steering control method that can modify and improve the vehicle lateral response without tire model and parameter. The proposed control algorithm is a combination of steady-state and transient control. The steady state control input is designed to modify steady-state yaw rate response of the vehicle, i.e. understeer gradient of the vehicle. The transient control input is a feedback control to improve the transient response when the vehicle lateral behavior builds up. The control algorithm has been investigated via computer simulations. Compared to classical control methods, the proposed algorithm shows good vehicle lateral response such as small overshoot and fast response. Specifically, the proposed algorithm can alleviate stair-shaped response of the lateral acceleration. In addition, through tests with low friction road and high lateral acceleration, the proposed algorithm’s performance is verified to be robust for a variety of road friction and

Park, Kwanwoo, Joa, Eunhyek, Yi, Kyongsu

Safety and Lateral Dynamics Improvement of a Race Car Using Active Rear Wing Control

2019-01-064304/02/2019

As the forward speed of a car increases, the safety of the vehicle and the driver becomes a more significant concern. Active aerodynamic control can effectively enhance the lateral stability of high speed vehicles over tight cornering maneuvers. A split rear wing has been proposed. By means of manipulating the attack angles for the right and/or left parts of the split rear wing, a favorable yaw moment may be achieved to ensure the lateral stability of the vehicle. However, active control of the split rear wing has not been adequately explored. This paper proposes a novel active split rear wing, which can improve the lateral stability over tight cornering maneuvers, and will not degrade the longitudinal dynamics of the vehicle. A Linear Quadratic Regulator (LQR) based controller for the active split rear wing is designed using a linear vehicle model. In order to examine the performance of the active split rear wing, Numerical simulation is carried out using the LQR based controller and

Hammad, Mohammed, Qureshi, Khizar, He, Yuping

Development and Control of Four-Wheel Independent Driving and Modular Steering Electric Vehicles for Improved Maneuverability Limits

2019-01-045904/02/2019

Electric vehicles are capable of more flexible drivetrain configurations, such that driving dynamics of each wheel could be controlled independently to increase its stability and maneuverability bounds. We hereby propose a configuration consisting of four wheel independent driving and front and rear axle modular steering. The vehicle implements drive-by-wire technology, which means the control program running on vehicle control computer will have direct control authority of the vehicle under normal driving conditions, based on inputs of higher level systems such as human drivers and autonomous driving programs. Both the torque allocation on four wheels and the steering allocation on axles are completely independent on the mechanical hardware level, thus the vehicle is able to harness adverse contact conditions with confidence. A slip-aware model-free control method for torque allocation and steering is proposed and inspected in the paper, with digital model of a modified SUV simulated

Yang, Haoguang, Liu, Chen, Shi, Jiongming, Zheng, Gangtie

GKN demos eTwinster 2-speed, torque-vectoring BEV transmission

19AUTP04_1104/01/2019

GKN Automotive unveiled what it claims is the world's first 2-speed, torque-vectoring transmission for battery electric vehicles (BEVs). Featured on GKN's 2019 Technology Demonstrator (GTD19)-a Jeep Renegade-based prototype-the EV-enhancing tranny was revealed to media during GKN's annual winter testing program in Arjeplog, Sweden. Combining several advances in GKN's driveline technologies, the coaxial eTwinster transmission could improve BEV efficiency as well as straight-line and handling performance. The new 2-speed “seamless shift” eTransmission has the potential to extend vehicle range while also providing increased torque for improved acceleration and a higher top speed, all while using smaller electric motors. Efficiency and further powertrain downsizing are enhanced by the eTwinster's coaxial layout, while improved stability and dynamic performance are possible thanks to its torque-vectoring capabilities.

Seredynski, Paul

Improving Multi-Axle Vehicle Steering Coordination Performance Based on the Concept of Instantaneous Wheel Turn Center

03/14/2019

A new concept of instantaneous wheel turn center (IWTC) is proposed to evaluate and improve multi-axle vehicle steering coordination performance. The concept of IWTC and its calculation method are studied. The index named dispersion of IWTC is developed to evaluate the vehicle steering coordination performance quantitatively. The simulation tests based on a three-axle off-road vehicle model are conducted under different vehicle velocities and lateral accelerations. The simulation results show that the turn centers of different wheels are disperse, and the dispersion becomes larger with the increase of vehicle velocities and lateral acceleration. Since suspension has important influences on vehicle steering performance, the genetic algorithm is used to optimize the suspension hard points and bushing stiffness, aiming at minimizing the dispersion of wheel turn centers (DWTC) to improve the vehicle steering coordination performance. The optimization results indicate that the suspension

Wang, Bo, Zha, Hongshan, Zhong, Guoqi, Weng, Shijing, Li, Qin, Lu, Pingping

Effects of Kingpin Inclination and Caster Angle on Kinematics and Lateral Dynamics of Long Wheelbase School Bus

2019-26-021901/09/2019

Camber angle of steered wheels varies with steering angle as a function of the kingpin inclination angle (KPIA) and caster angle. Thus, the aim of the study herein was to understand the possibility of control of KPIA and caster angle and thus also control camber angle during turn. Hence a detailed study has been done to evaluate the effects of KPIA and caster angle on kinematics and lateral dynamics of the school bus. TruckSim® simulation tool has been used to carry out a simulation study on an 8.5 tonne 6.45 m wheelbase bus model. This open loop study was done to evaluate individual and combined effects of the aforementioned input variables on camber angle which directly influences the kinematic and dynamic response of the bus. Thus, for both KPIA and caster angle variation, handling response metrics were studied for three different manoeuvres, namely straight path driving, steady-state circles and double lane change. The handling response metrics which were analysed include radius of

Jambukar, Sagar, Chandramohan, Sujatha

Investigation of Cabin Noise while Accelerating on Low Mu Track through Simulation Approach Using Full Vehicle ADAMS/Car Model

2019-26-017901/09/2019

Cabin noise is a significant product quality criteria which enables the customers for product differentiation. There are various sources of cabin noise such as wind, structures(panels), engine, suspension, tire and roads. During product development phase, extensive tests has been conducted to improve vehicle dynamics behavior on various climatic conditions. One such test is accelerating vehicle on low mu or icy surface. While performing acceleration manoeuvre (tractions) on a low mu tracks, Cabin noise with source identified from front underbody & low tractive torque build up is reported. This undesirable behavior may occur due to following reason (1) Excitation of coupled modes between suspension and powertrain which induces torque fluctuation. (2) Transmissibility of various subsystem can be the reason for above problem statement. (3) Poorly chosen tire compounds and design leads to fluctuation in torque. A detailed simulation based study using ADAMS/CAR has been performed to assess

Singh, Vivek, Prasad, Tej, Srivastava, Harshit

Methodology to Determine Optimum Suspension Hard Points at an Early Design Stage for Achieving Steering Returnability in Any Vehicle

2019-26-007401/09/2019

Steering returnability while driving is one of the most important parameter which affects the drive pleasure and handling of a vehicle. Steering returnability refers to the automatic returning response of the steering wheel after taking a full turn while vehicle is being steered during driving. Evaluating steering response characteristics of any vehicle in a virtual environment at early stage of a product development saves significant development time and cost. Through this paper an attempt has been made to develop a methodology for selection of suspension hard points which influences steering returnability characteristics of a vehicle at an early product design stage. Conventionally, suspension kinematic parameters such as Caster angle, Steering axis inclination (SAI), etc. are iterated during vehicle design stage to achieve desired Steering returnability. However, at times vehicle level trials indicate that increasing caster angle or SAI does not guarantee a desirable increase in

Khanna, Nitin Kumar, Jyoti, Manjul, S, Udhayakumar, Senthi, Karthik, Desai, Sakharam

1D Tire Model Parameter Synthesis for Vehicle Handling Targets Assessment “A Strategy of Optimization and Evaluation of Tire Math’s”

2019-26-036101/09/2019

Handling performance of a vehicle is a key characteristic determining the response of vehicle under different operating scenarios. An insight into these vehicle-handling characteristics at early stage can be extremely useful in the design and development process. Tire characterization and tuning is important and mandatory to scrutinize each functional and individual parameter of tire. Tire force and moment data is having a significant effect in vehicle handling. Segregation of tire parameter, which is contributing vehicle-handling performance, helps to identify and perform optimization for improvisation.The main objective of this study is development and integration optimized 1D tire model into multibody dynamics model of the vehicle to observe various vehicle compliances towards its handling performance target. First part of the work deals with 1D tire model parameter synthesis tool development utilized for calculation of tire parameters such as lateral force and aligning torque for

Pattathil, Arunmohan, Kumar, Sunil, Iqbal, Shoaib

Steady-State Directional Control Test Procedures for Passenger Cars and Light Trucks

J266_201811 (Current)11/28/2018

This SAE Recommended Practice establishes consistent test procedures for determination of steady-state directional control properties for passenger cars and light trucks with two axles. These properties include the steering-wheel angle gradient, reference steer angle gradient, sideslip angle gradient, vehicle roll angle gradient, and steering-wheel torque gradient with respect to lateral acceleration. They also include the yaw velocity gain, lateral acceleration gain, and sideslip angle gain with respect to steering-wheel angle. Additionally, the characteristic or critical speed and the front and rear wheel steer compliances may be determined.

Vehicle Dynamics Standards Committee

Enhanced Lateral and Roll Stability Study for a Two-Axle Bus via Hydraulically Interconnected Suspension Tuning

10-03-01-000111/19/2018

The suspension system has been shown to have significant effects on vehicle performance, including handling, ride, component durability, and even energy efficiency during the design process. In this study, a new roll-plane hydraulically interconnected suspension (HIS) system is proposed to enhance both roll and lateral dynamics of a two-axle bus. The roll-plane stability analysis for the HIS system has been intensively explored in a number of studies, while only few efforts have been made for suspension tuning, especially considering lateral plane stability. This article aims to explore the integrated lateral and roll dynamics by suspension tuning of a two-axle bus equipped with HIS system. A ten-degree-of-freedom (DOF) lumped-mass vehicle model is integrated with either transient mechanical-hydraulic model for HIS or the traditional suspension components, namely, shock absorber and anti-roll bar (ARB). Three novel parameters of HIS system are proposed as the suspension tuning rules

Qi, Hengmin, Zhang, Bangji, Zhang, Nong, Zheng, Minyi, Chen, Yuanchang

Identification and Resolution of Vehicle Pull and Steering Wobble Using Virtual Simulation and Testing

2018-01-189510/05/2018

A vehicle drifts due to several reasons from its intended straight path even in the case of no steering input. Vehicle pull is a condition where the driver must apply a constant correction torque to the steering wheel to maintain a straight-line course of the vehicle. This paper presents an investigation study into the characteristics of a vehicle experiencing steering drift. The aim of the work is to study vehicle stability and the causes of vehicle drift/pull during straight line to minimize vehicle pull level and hence optimize safety measures. A wobble in the steering wheel feels like the steering wheel is shaking to the left and right. This may get worse, if speed increases. This paper focuses on modelling and evaluating effects of suspension parameters, differential friction, brake drag variation, Unbalanced mass in the wheel assembly and C.G. location of the vehicle under multibody dynamic simulation environment. Asymmetry of geometry and compliance between left and right side

Anthonysamy, Baskar, Barde, Vishal, Medithi, Naveen, S, Senthil, N, Balaramakrishna

Development of semi-active suspension for Formula SAE vehicle

2018-36-022409/03/2018

The design of passive suspension systems is being improved since the early days of the automotive industry in order to obtain the best tradeoff between ride comfort and handling. In this context, passenger cars tend to prioritise ride comfort whilst racing cars tend to focus on handling. On the other hand, Formula SAE is a series of undergraduate competitions in which the students design, build and compete with small, formula-style, mono-seated vehicles. As part of the competition events, the vehicle experiences tight corners and short-length slaloms. The minimum turning diameter and the shortest length of slalom period conducted by Formula SAE prototypes are 9 m and 7.6 m, respectively. Therefore, high controllability of vehicle dynamic behaviour is required in order to enhance the cornering speed, this is achievable by working on the dampers to optimise the rates of load transfer in cornering. This paper describes the development of semiactive control algorithms to optimise the

dos Santos, Marcos Gabriel Diodato, Chrysakis, Georgios, Willmersdorf, Ramiro Britto, Alves, Luiz Otávio Ferrão Teixeira

Developmental Driver Model for Long Vehicles Based on Preview-Follower Theory

2018-01-162908/07/2018

A long vehicle is more difficult to drive than a short one, but the mechanism of this phenomenon is still ambiguous. This paper will devote main effort to elaborate this phenomenon based on the theory of preview-follower driver model. Drivers always hope that the vehicle center can travel according to a predetermined trajectory. However, there is often a deviation between the vehicle center predicted by the driver and the actual center. As for this phenomenon, a conception of driver preview eccentricity is proposed. In order to analyze the influence of the proposed conception on vehicle driving track, a multi-axle steering vehicle model is built and some basic expressions of important parameters are deduced from this model firstly. Then, the developmental driver model with the factor of preview eccentricity based on preview-follower theory is established in the state of low velocity quasi-static. Subsequently, this model for long vehicles is extended to a dynamic driver model. At last

Chen, Xiang, Guo, Konghui

Passenger Car Handling Characteristics Associated with Space-Saver Spare Tires

2018-01-502707/12/2018

Space-saver spare tires have become near-standard equipment in passenger cars, replacing full-size spares. The properties of space-saver spare tires (cornering stiffness, self-aligning torque, etc.) exhibit some differences when compared to standard size tires. We examine potential handling changes when a space-saver tire is installed on the vehicle by examining steady-state behavior, initial step steering response, and vehicle understeer gradient as functions of the mounting location of the space-saver tire (front or rear axle). Results show that space-saver spare tires perform well and are quite capable in low-ay, linear handling maneuvers.

Metz, L. Daniel

Vehicle Stability Control through Optimized Coordination of Active Rear Steering and Differential Driving/Braking

06-11-03-002007/05/2018

In this article, a hierarchical coordinated control algorithm for integrating active rear steering and driving/braking force distribution (ARS+D/BFD) was presented. The upper-level control was synthesized to generate the required rear steering angle and external yaw moment by using a sliding-mode controller. In the lower-level controller, a control allocation algorithm considering driving/braking actuators and tire forces constraints was designed to assign the desired yaw moment to the four wheels. To this end, an optimization problem including several equality and inequality constraints were defined and solved analytically. Finally, computer simulation results suggest that the proposed hierarchical control scheme was able to help to achieve substantial enhancements in handling performance and stability. Moreover, the comparison between ARS+D/BFD and AFS+D/BFD (active front steering and driving/braking force distribution) by using the proposed controller was presented and analyzed.

Zhou, Zhou, Miaohua, Huang

Active Suspension: Future Lessons from The Past

10-02-02-001006/18/2018

Active suspension was a topic of great research interest near the end of last century. Ultimately broad bandwidth active systems were found to be too expensive in terms of both energy and financial cost. This past work, developing the ultimate vehicle suspension, has relevance for today’s vehicle designers working on more efficient and effective suspension systems for practical vehicles. From a control theorist’s perspective, it provides an interesting case study in the use of “practical” knowledge to allow “better” performance than predicted by theoretically optimal linear controllers. A brief history of active suspension will be introduced. Peter Wright, David Williams, and others at Lotus developed their Lotus modal control concept. In a parallel effort, Dean Karnopp presented the notion of inertial (Skyhook) damping. These concepts will be compared, the combination of these two distinctly different efforts will be discussed, and eventual vehicle results presented. Most of the

Williams, Daniel Eugene

Trimmed Body Static Stiffness Identification Using Dynamic Measurements: Test Methodology and Correlation with CAE Results

2018-01-149606/13/2018

A key metric of a car body structure is the body stiffness, which shows significant correlation with different vehicle performance attributes as NVH, comfort and vehicle handling. Typical approaches to identify static stiffness characteristics are the use of a static stiffness test bench or the ‘static-from-dynamic’ approach in which free-free acquired transfer functions are used to build a modal model from which the static stiffness characteristics are extracted. Both of these approaches have limitations, the static stiffness bench with respect to clamping conditions and reproducing those in CAE, the static-from-dynamic with respect to the modal analysis (EMA) that needs to be performed. EMA is a subjective process, which can limit result robustness. In addition, performing EMA on a trimmed body is difficult due to the high modal density and the high level of damping. Strong benefit however of the static-from-dynamic approach is the ability to characterize the body stiffness without

Ottaiano, Simona Anna, Geluk, Theo, Teipen, Elmar, El-Kafafy, Mahmoud

Dynamic Characteristics Analysis of an Ambulance with Hydraulically Interconnected Suspension System

2018-01-081504/03/2018

The vibration and instability experienced in an ambulance can lead to secondary injury to a patient and discourage a paramedic from emergency care. This paper presents a hydraulically interconnected suspension (HIS) system which can achieve enhanced cooperative control of roll, pitch and bounce motion modes to improve the ambulance's ride comfort and handling performance. A lumped-mass model integrated with a mechanical and hydraulic coupled system is developed by using free-body diagram and transfer matrix methods. The mechanical-fluid boundary condition in the double-acting cylinders is modelled as an external force on the mechanical system and a moving boundary on the fluid system. A special modal analysis method is employed to reveal the vibration characteristics of the ambulance with the HIS. A series of frequency analyses, including free vibration with identified eigenvalues and eigenvectors, vibration transmissibility and force vibration with stochastic road inputs, are

Tan, Bohuan, Wu, Yang, Zhang, Nong, Zhang, Bangji, Zheng, Minyi, Qi, Hengmin

Multi-Objective Optimization to Improve SUV Ride Performances Using MSC.ADAMS and Mode Frontier

2018-01-057504/03/2018

Ride is an important attribute which must be accounted in the passenger segment vehicles. Excessive H point acceleration, Steering wheel acceleration, Pitch acceleration can reduce the comfort of the driver and the passengers during high frequency and low frequency rough road events. Excessive Understeer gradient, roll gradient, roll acceleration and Sprung mass lift could affect the Vehicle driver interaction during Steady state cornering, Braking and Step steer events. The concept architecture of the vehicle plays an important role in how comfort the vehicle will be. This paper discusses how to improve SUV ride performances by keeping handling performance attributes same or better than base vehicle. Multi Objective Optimization was carried out by keeping spring, bushing and damper characteristic as the design variables to avoid new system or component development time and cost. The first step in this process is DOE (Design of Experiments method) which allows to select critical or

Lenka, Visweswara Rao, Anthonysamy, Baskar, Londhe, Abhijit, Hatekar, Harshad

Handling Improvement for Distributed Drive Electric Vehicle Based on Motion Tracking Control

2018-01-056404/03/2018

The integrated control system which combines the differential drive assisted steering (DDAS) and the direct yaw moment control (DYC) for the distributed drive electric vehicle (DDEV) is studied. A handling improvement algorithm for the normal cornering maneuvers is proposed based on motion tracking control. Considering the ideal assistant power character curves at different velocities, an open-loop DDAS control strategy is developed to respond the driver’s demand of steering wheel torque. The DYC strategy contains the steering angle feedforward and the yaw rate feedback. The steering angle feedforward control strategy is employed to improve yaw rate steady gain of vehicle. The maximum feedforward coefficients at different velocities are obtained from the constraint of the motor external characteristic, final feedforward coefficients are calculated according to the ideal assistant power character curve of the DDAS. Meanwhile, an integral anti-windup PI control is proposed to track

Yang, Xing, Xiong, Lu, Leng, Bo, Li, Yue

A Study of Suspension Tightening Torque on the R&H Performance of High Performance Vehicles

2018-01-057704/03/2018

Suspension is a system which operates dynamically according to road condition unlike other system statically mounted to the body. Especially this is more remarkable in high performance vehicle because there are more high inputs from road to suspension than normal vehicle. For this reason, the tightening torque of suspension system of high performance vehicle is more important than other systems and normal vehicle. To support the clamping between parts against force from road when cornering, optimized tightening torque is required to maximize R&H performance. For this optimization, it should be conducted first to comprehend how much performance effects on vehicle by tightening torque. This paper presents relationship between tightening torque of suspension parts hardware and R&H performance. Also for the robust mounting, it is focused on what managing method of clamping force and what kinds of mounting structure are efficient. 1 To investigate the tightening torque effect, blind driving

Song, Jieun, Lee, Byung-Kyu, Yoo, Sang-Hoon, Lee, Dae Hyeong

Parameters Analysis of on-Center Handling for Articulated Trucks

2018-01-013604/03/2018

On-center handling is one of the most important test conditions which are used to evaluate the handling performance of both passenger cars and commercial vehicles. This paper aims at investigating and verifying the influence of parameters on on-center handling of articulated trucks. A full vehicle model, including the steering system, suspension system, cab, frame, trailer and so on, was established in first by measuring the parameters of each component. The comparison of simulation and test results shown that the simulation precision of the vehicle model was up to 80%. Based on the model, the influence analysis of parameters, such as stiffness of steering drag link, steering ratio, kingpin friction, were carried out and were verified through the handling test. The analysis results indicated that larger stiffness of steering drag link, smaller gear ratio could enhance the steer sensitivity and steer stiffness, small kingpin friction is beneficial to the steering return ability.

Jiang, Xuefeng, Liu, Xiang, Chen, Wei, xie, hao, Sun, Zhe

Research on the Dynamic Integration Control for Distributed-Traction Electric Vehicle with Four-Wheel-Distributed Steering System

2018-01-081404/03/2018

With rapid development of the automobile industry and the growing maturity of the automotive electronic technologies, the distributed-traction electric vehicle with four-wheel-distributed steering/braking/traction systems is regarded as an important development direction. With its unique chassis structure, it is the ideal benchmark platform used to evaluate active safety systems. The distributed-traction electric vehicle with four-wheel-distributed steering system is essentially full drive-by-wire vehicle. With its flexible chassis layout and high control degrees-of-freedom, the full drive-by-wire electric vehicle acted as a kind of redundant system is an ideal platform for the research of integrated control. In this treatise, the longitudinal dynamics of the electric vehicle as well as its lateral and yaw motions are controlled simultaneously. In the motion control layer, the total force and total torque of the vehicle motion control are obtained by using the sliding mode controller

Wang, Jiantao, Zong, Changfu, Zheng, Hongyu, liu, Chen, Cheng, Cheng

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