Browse Topic: Four wheel steering

Items (63)

Analytical modeling and multi-objective optimization of the articulated vehicle steering system

2022-01-106003/29/2022

Articulated steering system is widely used in engineering vehicles due to its high mobility and low steering radius. The design parameters have a vital impact on the selection of the steering system assemblies, such as the operation stroke, pressure, and force of the hydraulic cylinders during the steering process, which will affect the system weight. The energy consumption is also relevant to the geometry parameters. According to the kinetic analysis of the steering system and dynamic analysis of the steering process, the kinetic model of an engineering vehicle steering system is established, and the power needed to boost it is calculated and validated by the field test result. The influence of the factors is analyzed based on this model. To lower the system weight and needed pressure, the multi-objective particle swarm optimization method is initiated to optimize the geometry parameter of the articulated steering system. After optimization, the weight of the system decreased by

Peng, Dengzhi

Construction and Test of Wireless Remote Control System for Self-driving Car

2022-01-006103/29/2022

Aiming at the test safety problems in the early stage of self-driving cars development, firstly the virtual vehicle on-board CAN data acquisition module of the present project was designed based on virtual LabVIEW. Then a wireless remote control system for the self-driving car was constructed, which integrated the built virtual vehicle on-board CAN data acquisition system, the remote real-time image monitoring module and the remote upper computer control module based on ZigBee wireless transmission. It can execute the environmental awareness training and continuous and complex motion manipulation testing of the vehicle without relying on the driver, which can solve the safety problems in the tests of initial development of self-driving cars. Finally, the four-wheel independent steering electric vehicle was used as the self-driving test vehicle, and the wireless remote control system was tested on the double lane change type path and S-type path. During the testing, the self-driving car

Zhou, Su, Xie, Zhengchun, Zhang, Gang, Hirz, Mario

A Study on the Concept Design of 4-Wheel Independent Steering system and Driving mode

2022-01-111803/29/2022

Recently, there are lots of customers' requirements for future mobility such as narrow space movement, increased driving freedom, and ease of parking are emerging. And the key leading technologies to implement them are 4-Wheel independent Steering(4WS) technology. In this study, we will introduce the concept design approach of 4-corner steer module and how to prove the design. Last but not least, we defined the basic driving mode of 4WS and specified how to control the 4-corner steer module.

MOON, HA KYUNG

Controller design for path tracking of autonomous vehicle incorporating four-wheel steering system

2022-01-034603/29/2022

This research aims to model and assess autonomous vehicle controller while including a four-wheel steering and longitudinal speed control. Such a modeling process simulates human driver behavior with consideration of real vehicle dynamics’ characteristics during standard maneuvers. However, a four-wheel steering control improves vehicle stability and maneuverability as well. A two-degree of freedom bicycle model, lateral deviation and yaw angle, is constructed to describe vehicle dynamics’ behavior. Moreover, a comprehensive traction model is implemented which includes an engine, automatic transmission, and non-linear magic formula tire model for simulation of vehicle longitudinal dynamics. A combination of PID longitudinal controller and fuzzy lateral controller are implemented simultaneously to track the desired vehicle path while minimizing lateral deviation and yaw angle errors. Then, A LQR based rear steering controller is introduced to represent a performance improvement over

Gafar, Ibrahim, Oraby, Walid, Aly, Mahmoud Atef

Mecalac designs unique-pivoting swing loader

20TOFHP08_0908/01/2020

Mecalac markets itself as an urban-equipment manufacturer, and the company's focus on designing machines for constricted-space jobsites so prevalent in cities is manifested in the AS1600 swing loader. According to Peter Bigwood, general manager for Mecalac North America, the AS1600 - and all models in the AS Swing Loader Series - departs from traditional wheel loader design by offering the “unique ability” to pivot its fully-loaded bucket 90 degrees to either side. “On today's crowded jobsites, space management is vital for safety, productivity and efficiency,” said Bigwood. “Contractors are trying to fit all the equipment, vehicles and personnel they need into a very limited space, leading to congestion and sometimes dangerous conditions. Our engineers are always looking to optimize equipment utilization, providing the solutions that let operators do things that they cannot accomplish with other machines.”

Gehm, Ryan

Study of skid steering method for distributed-drive articulated heavy vehicle based on the co-simulation model

2020-01-076104/14/2020

Distributed-driver articulated steering vehicles (DASVs), the particular engineering equipment, have good maneuverability and tractability in poor road and narrow space conditions. They are always used in the mining, construction, forest, and agricultural industry. Its structure comprise front and rear frame connected by an articulation joint and two hydraulic struts. In the steering process, these two struts are driven by pump of hydraulic system, and the vehicle will turn following the control of steering wheel with the coupling effects of articulation joint and struts. But due to the high load of the DASVs, the influence of pressure of outlet chamber, and the compressible of the oil, it is easy to cause the high pressure level, the low energy efficiency, and poor stability in hydraulic steering process. This is not conducive to improving the security, economy, and stability of DASVs. Therefore, in order to solve these problems, this paper will make the DASVs as the objective vehicle

Xu, Tao, Ji, Xuewu, Fei, Cong, Liu, Yahui, Shen, Yanhua

Bike with Modified Steering System to Assist People with Forearm Disability

2018-28-006207/09/2018

Individuals with mobility impairments are people who have lost their functionality of leg and hand due to birth, diseases or accidents. Various commercial bike designs are existing in the market for bike riders with disability in their legs designed with dummy rear axle. But no designs exits for bike riders with disability in their hands which is being available in market. To ride a bike steering, brake and acceleration controls has to be provided by an alternate method. It was proposed to develop a bike for person with disability in their hand. The design of the bike and in particular steering system was done using of Autodesk Inventor software and analysed using ANSYS workbench to assess the structural integrity of the design. The design was transformed in to a complete working prototype and found to be working satisfactory.

Mathiyalazhan, Vivekananthan, Elsen, Renold

Sliding Mode Predictive Tracking Control for Electric Vehicle Using Steer-By-Wire System

2018-01-069704/03/2018

Recently, a lot of electric vehicle (EV) has been developed to improve the energy consumption problem and electric power steering system has attracted the researchers’ concern. Steer-by-Wire (SbW) system is an electric steering system where the mechanical link between the steering wheel and front wheels is eliminated. Due to the absence of direct mechanical linkage, the most challenging issue is to ensure that the front wheels closely follow the driver’s command. A sliding mode predictive controller (SMPC) for Steer-by-Wire systems (SbW) is proposed to achieve a proper tracking performance. The sliding mode predictive controller has two parts: sliding mode control (SMC) and model predictive control (MPC). The SMC is applied to improve the robustness of MPC in the presence of model uncertainties while the MPC is applied to enhance the tracking performance of SMC. The simulation results and experimental results demonstrate the effectiveness of the proposed controller in steering angle

Huang, Chao, Naghdy, Fazel, Du, Haiping

The Trajectory Planning of the Lane Change Assist Based on the Model Predictive Control with Multi-Objective

2017-01-200409/23/2017

The automatic lane change assist system is an intelligent driving assistance technology oriented to traffic safety, which requires trajectory planning of the lane change maneuver based on the lane change decision. A typical scene of lane change for overtaking is selected, where the front vehicle in the same lane and the rear vehicle in the left lane are deemed to be potential dangerous vehicles through the lane change. Lane change trajectory equation is first established according to the general law of steering wheel angle through lane changes. Based on the relative position, velocity and acceleration information of the dangerous vehicles and the lane change vehicle, motions of these surrounding dangerous vehicles are predicted. At the same time, a multi-objective optimization function is established based on the relative longitudinal safety boundary. The objectives are the minimum safety distance, the lane change time and the front wheel angle. The trajectory planning algorithm of the

Wang, Yangyang, Feng, Rong, Pan, Ding, Liu, Zhiguang, Wu, Nan, Li, Wei

Study on Energy Loss due to Cornering Resistance in Over-Actuated Vehicles using Optimal Control

2017-01-156803/28/2017

As vehicles become electrified and more intelligent in terms of sensing, actuation and processing; a number of interesting possibilities arise in controlling vehicle dynamics and driving behavior. Over-actuation with in- wheel motors, all wheel steering and active camber is one such possibility, which facilitate the control strategies that push boundaries in energy consumption and safety. Optimal control can be used to investigate the best combinations of control inputs to an over-actuated system. This paper shows how an optimal control problem can be formulated and solved for an over-actuated vehicle case, and highlights the translation of this optimal solution to a real-world scenario, enabling intelligent means to improve vehicle efficiency. This paper gives an insight into Dynamic Programming (DP) as an offline optimal control method that guarantees the global optimum. Therefore the optimal control allocation to minimize an objective function and simultaneously fulfill the defined

Bhat, Sriharsha, Davari, Mohammad Mehdi, Nybacka, Mikael

AGILITY TRAINING FOR CARS

16MEIP06_0406/01/2016

Chassis component suppliers refine vehicle dynamics at the high end and entry level with four-wheel steering and adaptive damping. As personal mobility moves toward the perhaps inevitable singularity of automatically piloted pods able to totally isolate passengers from any sensation of the surrounding world, today's manually piloted cars are adding systems to aid with guidance and improve isolation from bumps in the road. The 2016 BMW 7 Series not only features computer-steered rear wheels that assist the driver, but its GPS system uses data on road surfaces to tune the response of the car's air suspension system.

Carney, Dan

Automotive Engineering: March 3, 2016

16AUTP0303/03/2016

Multi-material structures move mpg upward The quest to improve fuel economy is not waning, nor is the desire to achieve higher mpg through the use of just the right lightweight material for the right vehicle application. Cars poised to become 'a thing' Making automobiles part of the Internet of Things brings both risks and rewards. Agility training for cars Chassis component suppliers refine vehicle dynamics at the high end and entry level with four-wheel steering and adaptive damping. SAE 2016 World Congress Preview Technology trends and exhibitor products are highlighted in this special section, which features Toyota's plans for the show floor, tech sessions, and more. Rethinking the route to lower-cost fuel cells Secondary loop and heat pump climate control under evaluation once more OTA reflashing: the challenges and solutions 3D-printed high-temperature ceramics 2017 Pacifica is first hybrid minivan, rides on all-new FCA platform Prius is re-engineered on Toyota New Global

AGILITY TRAINING FOR CARS

16AUTP03_0303/01/2016

Carney, Dan

Driving and Steering Coordination Control for 4WID/4WIS Electric Vehicle

2015-01-276209/29/2015

This paper presents an integrated chassis controller with multiple hierarchical layers for 4WID/4WIS electric vehicle. The proposed systematic design consists of the following four parts: 1) a reference model is in the driver control layer, which maps the relationship between the driver's inputs and the desired vehicle motion. 2) a sliding mode controller is in the vehicle motion control layer, whose objective is to keep the vehicle following the desired motion commands generated in the driver control layer. 3) By considering the tire adhesive limits, a tire force allocator is in the control allocation layer, which optimally distributes the generalized forces/moments to the four wheels so as to minimize the tire workloads during normal driving. 4) an actuator controller is in the executive layer, which calculates the driving torques of the in-wheel motors and steering angles of the four wheels in order to finally achieve the distributed tire forces. Experimental verification is made to

Li, Chunshan, Song, Pan, Chen, Guoying, Zong, Changfu, Liu, Wenchao

Development and Control of Evasive Steer Assist Using Rear Wheel Steering

2015-26-000401/14/2015

A first step towards autonomous rear-end collision avoidance is to start providing natural support to driver in avoiding collision by steering and braking intervention. The proposed system detects slower-moving and stationary vehicles ahead and classifies the risk of having a rear-end-collision. If the risk is high and there is insufficient space to avoid a collision by braking only, the system helps the driver to steer around the obstacle by steering rear toe angle of the wheels individually. A lot of research already exist in the rear wheel steering but the role of rear wheel steering in collision avoidance is not researched yet in great details. Rear wheel steering is used to increase agility and manoeuvrability of vehicle at lower vehicle speed and stability of vehicle at higher vehicle speed. In the situation of the high speed rear end collision where steering is more effective than braking the strategy of control design of rear wheel steering needs to be dynamically updated

Shah, Jitendra

An Innovative Design Concept of Four Wheel Steering Mechanism for an Automobile

2013-01-284511/27/2013

The main characteristic of vehicle moving on road is related to its response to the drivers command and to environmental factors affecting the direction of motion of vehicle. The two basic problems in handling the vehicle are control of vehicle along the desired path and stabilization of the direction of motion of vehicle against external disturbances. The vehicle with best handling characteristics is the vehicle which can always be controlled by the driver. While parking the vehicle and doing sharp turnings the vehicle with two wheel steering cannot be more significant. The two wheel steering system takes large radius of turning and requires more space to take turn. Hence four wheel steering is preferable than two wheel steering systems. A multi-function four wheel steering system could improve directional stability at high speeds, sharp turning performance at low speeds, and parking performance of a vehicle. Generally there are three types of steering systems which include front

Vanamala, Uma Maheshwar, koganti, Raja Rao

Pump Controlled Steer-by-Wire System

2013-01-234909/24/2013

Modern on-road vehicles have been making steady strides when it comes to employing technological advances featuring active safety systems. However, off-highway machines are lagging in this area and are in dire need for modernization. One chassis system that has been receiving much attention in the automotive field is the steering system, where several electric and electrohydraulic steering architectures have been implemented and steer-by-wire technologies are under current research and development activities. On the other hand, off-highway articulated steering vehicles have not adequately evolved to meet the needs of Original Equipment Manufacturers (OEM) as well as their end customers. Present-day hydrostatic steering systems are plagued with poor energy efficiency due to valve throttling losses and are considered passive systems relative to safety, adjustability, and comfort. This paper introduces a novel scheme of an electro-hydraulic power steering system that utilizes a proven

Daher, Naseem A., Ivantysynova, Monika

Autonomous Mechatronics-Based Locomotion Module for Multi-Wheel Vehicle and Terrestrial Robot Applications

2012-01-191309/24/2012

The main trend in designs of modern automobiles is a widespread use of mechatronic modules and systems. These modules are built as a symbiosis of electric, electronic and hydraulic components, united by means of the control system and intended to fulfill particular targeted functions. In the article results of a comprehensive theoretical and experimental study aimed at creating a drive and a control system of a wheel module intended to be used with the steering and spring systems of an automobile and a mobile robot have been considered. Also the basic principles of the a complex of mechatronic drives of the wheel module (CMD WM) and technical requirements for the components of the complex as a mechatronic module of the system of active safety of the automobile and mobile robot have been formulated. The operation of all the subsystems of the CMD WM of the all-wheel steering system with various types of the electro-hydraulic servo drive of wheel turning, and with the regulated wheel

Beloousov, Boris N., Naumov, Sergei V., Ksenevich, Tatiana I.

A Comparative Study of Active Control Strategies for Improving Lateral Stability of Car-Trailer Systems

2011-01-095904/12/2011

This paper examines the performance of different active control strategies for improving lateral stability of car-trailer systems using numerical simulations. For car-trailer systems, three typical unstable motion modes, including trailer swing, jack-knifing and roll-over, have been identified. These unstable motion modes represent potentially hazardous situations. The effects of passive mechanical vehicle parameters on the stability of car-trailer systems have been well addressed. For a given car-trailer system, some of these passive parameters, e.g., the center of gravity of the trailer, are greatly varied under different operating conditions. Thus, lateral stability cannot be guaranteed by selecting a specific passive parameter set. To address this problem, various active control techniques have been proposed to improve handling and stability of car-trailer systems. Feasible control methods involve active trailer steering control (ATSC) and active trailer braking (ATB). Recently, a

Shamim, Rafay, Islam, Md Manjurul, He, Yuping

Integrated Control of Active Steering and Electronic Differentials in Four Wheel Drive Vehicles

2009-01-044604/20/2009

In this paper the integrated control of front and rear active differentials with active front steering is investigated in order to improve dynamics, stability and to reduce the drawbacks of mechanical self-locking differentials. The proposed integrated centralized control feeds back both the yaw rate and the wheel speed measurements to the control inputs which are the front wheel steering angle and the torque transferred by the electronic differentials between the left and the right wheels of both vehicle's axles. The control of the electronic differentials is not only aimed at keeping the wheel speed differences at desired values but it is also integrated with the active steering control (a PI action from the yaw rate error) to produce a yaw moment (also depending on the yaw rate error) which improves handling and stability. Several simulations are carried out on a CarSim small SUV model to explore the robustness with respect to unmodelled dynamics such as pitch, roll and nonlinear

Marino, Riccardo, Scalzi, Stefano

Modeling and Simulation of a Hydraulic Steering System

2008-01-270410/07/2008

Conventional hydraulic steering systems keep improving performance and driving comfort by introducing advanced features via mechanical design. The ever increasing mechanical complexity requires the advanced modeling and simulation technology to mitigate the risks in the early stage of the development process. In this paper, we focus on advanced modeling tools environment with an example of a load sensing hydraulic steering system. The complete system architecture is presented. Analytical equations are developed for a priority valve and a steering control unit as the foundation of modeling. The full version of hydraulic steering system model is developed in Dymola platform. In order to capture interaction between steering and vehicle, the co-simulation platform between the hydraulic steering system and vehicle dynamics is established by integrating Dymola, Carsim and Simulink. Finally, the complete hydraulic steering system is executed in Opal-RT RT-Lab HIL simulator to allow human in

Yuan, QingHui, Xie, Bo

Fault-Tolerant Architecture of Yaw Moment Management with Steer-by-Wire, Active Braking and Driving-Torque Distribution Integrated Control

2008-01-011004/14/2008

A Steer-by-wire (SBW) system, which has no mechanical linkage, is expected to support the driver even in critical situations so as to improve collision safety and cockpit design flexibility. We have shown the effectiveness of driver assistance using an active steering control integrated with active braking control.[1] This is a case of normal driving without any vital component failures. The SBW system failure, however, can lead to an unsafe driving situation. A highly redundant design reduces the SBW failures but complicates its design and increases cost, volume and weight. This paper proposes a new fault-tolerant architecture to cope with the SBW failure. This is based on an integrated control by SBW, active braking, and driving torque distribution. A feasibility study is made using a driving simulator experiment during front obstacle avoidance under failed SBW. The proposed integrated control alleviates requirements for excessive redundancy of SBW components and thus facilitates

Hayama, Ryouhei, Higashi, Masayasu, Kawahara, Sadahiro, Nakano, Shirou, Kumamoto, Hiromitsu

The Co-simulation of Steering and Suspension System with ADAMS&Matlab/Simulink

2007-01-366608/05/2007

Based on the tire and road model of virtual prototype, using the co-simulation of ADAMS&Matlab/Simulink, combining with the optimal control theory, contrastive research is done among the system of passive suspension and front wheel steering the simple combination system of active suspension and four wheel steering and the integrated system of active suspension and four wheel steering. The theory analysis and simulation test indicate the integrated control system can greatly improve handling and riding performance of vehicle.

Fei, Lai, ZhaoXiang, Deng, Hongliang, Dong, Youqiang, Cao

A Comparison of Two Soft-Sensing Methods for Estimating Vehicle Side Slip Angle

2007-01-358708/05/2007

Two soft-sensing methods which are neural network and Kalman filter for estimating vehicle side slip angle are compared. A radial basis function (RBF) neural network based soft-sensing model is proposed to estimate vehicle side slip angle in driver-vehicle closed-loop system. Vehicle side slip angle is considered as mapping of time series of yaw rate and lateral acceleration which are easily measured, the nonlinear mapping relationship of the three state parameters is established through neural network. In addition the method based on Kalman filter is also given. The results of comparison between estimation and measurement show that the neural network method proposed in this paper has higher accuracy and less computation requirement. It can provide theoretical guidance for design of estimator in vehicle stability control system.

Lin, Fen, Zhao, Youqun

Development of Electric Active Stabilizer Suspension System

2006-01-153704/03/2006

The electric active stabilizer suspension system, which can reduce roll angle, has been developed. This paper presents the configuration, function and effect of the system. The electric active stabilizer suspension system performs not only decreasing roll angle but good fuel consumption. The rotary actuator of this system consists of the DC brushless motor and strain wave gearing. It has been confirmed that the system achieved target roll angle and contributed to improve fuel consumption compare to hydraulic system.

Suzuki, Satoshi, Buma, Shuuichi, Urababa, Shingo, Nishihara, Akio, Taneda, Akiya

Stability Control of Articulated Steer Vehicles by Passive and Active Steering Systems

2005-01-357311/01/2005

To remove the snaking mode of an articulated steer vehicle, an active steering system is proposed. First, the existing steering systems of articulated steer vehicles, including hydraulic-mechanical and hydrostatic steering systems, are reviewed. Then, a combined linearized model of the vehicle with a hydraulic-mechanical steering system is developed. By using this model, two passive methods to decrease the snaking, including an increase in the friction at the articulation joint and leakage across the cylinders are detailed. To overcome the shortcomings of these solutions, an active steering system is also introduced. It is shown that the proposed steering system not only removes the instability, but also improves the steering response of the vehicle.

Azad, N. L., Khajepour, A., McPhee, J.

Electric Actuation Technologies for Automotive Steering Systems

2005-01-127504/11/2005

An actual trend in the automotive industry represents the introduction of decentralized electric drive systems in different areas of application. Automotive steering systems represent a very important challenge for the electric drives. Active steering, electric power-assisted steering, electro-hydraulic power-assisted steering and full power steering (steer-by-wire) are the main target systems for electric actuation. Different topologies of these steering systems lead to special solutions for the electric drives. The paper presents on overview of actual high performance electric actuation technologies for automotive steering systems and offers therefore solutions based on permanent magnet synchronous motors (PMSM).

Iles-Klumpner, D., Risticevic, M., Hartkorn, H. W., Lahm, G., Serban, I., Boldea, I.

New Generation of Inertial Sensor Cluster for ESP- and Future Vehicle Stabilizing Systems in Automotive Applications

2003-01-019903/03/2003

In 1995 Robert Bosch GmbH (RB) started the mass production of the first VDC-System (Vehicle Dynamics Control system) for vehicles, today called ESP (Electronic Stability Program). This ESP-System went beyond ABS and Traction Control Systems and offered consumers unsurpassed driving confidence and safety. The key part of this system was a first generation Yaw Rate Sensor DRS 50/100, based on a metal vibrating cylinder. The second generation DRS MM1, introduced in 1998, based on silicon micromachining and included an integrated linear acceleration sensor element. For new additional functions of ESP and of future high dynamic and high performance vehicle stabilizing systems, like Hill Hold Control (HHC) or Steer by Wire (SbW) BOSCH develops the third generation, a flexible and cost-effective Inertial Sensor Cluster with a modular concept for hard- and software, called DRS MM 3.x. For all inertial sensor elements silicon surface micromachining is used. A fully digital signal processing

Willig, R., Mörbe, M.

Two Motor Electric Axle

2002-01-191906/03/2002

The paper presents a possible concept design for integration of individual wheel AC motors into Oshkosh Truck Corporation's InDependent Suspension. A new axle concept design (including drive line and CV-joint) is presented with a new AC induction motor concept. Both concepts are able to match 100% the sever-heavy duty requirements in a large area of advanced on and off road traction applications. Concepts are suitable for modularity in a multi-axle (2-6) All-Wheel Drive, All Steer configuration vehicle.

Cantemir, Codrin-Gruie, Rizzoni, Giorgio, Soliman, Ahmed, Yakes, Chris

A Coordination Approach for DYC and Active Front Steering

2001-01-127503/05/2001

Integrating chassis control systems can lead to improvements in the safety, efficiency of action and overall production of a modern car. The sharing of information between chassis sub-systems allows the controller to take the optimum course of action since it has more than one option to affect the dynamics of a vehicle. This paper investigates the principle of coordination of chassis subsystems by selecting active steering and yaw stability control. A controller that coordinates the action of active front steering(AFS) and direct yaw moment control(DYC) is proposed. Preliminary results for the coordinated controller using limit handling tests suggest that such an integrated approach can lead to overall improvements in vehicle dynamic response.

Selby, M., Manning, W. J., Brown, M. D., Crolla, D. A.

Application of feedforward controller on a four-wheel-steering car: The concept

2000-05-035206/12/2000

In this paper will be presented an alternative of feedforward controller (FFC) system to overcome four-wheel-steering weaknesses. The system estimates vehicle output parameters that consists of lateral acceleration (v), roll rate (ϑ) and yaw rate (φ) as well as the correct input parameters of vehicle that consists of longitudinal sped (Uo) and steering wheel (δsw). To estimate vehicle output parameters used will be full car mathematical model. The estimated vehicle output parameters together with given vehicle input parameters are used to estimate understeer coefficient (Ku). Finally, it will be used to compute the correct vehicle input parameters required by the 4WS system.

Sampurno, Bambang, Tjokronegoro, H. A., Farida, I. M., Arismunandar, W.

Dynamic characteristics of multi-function four-wheel steering system

2000-05-024506/12/2000

Turning at high speed, doing sharp turning at low speed, and doing parking are three critical motions of a vehicle needed to be considered. This research studied dynamic characteristics of a multi-function four-wheel steering system that could improve directional stability of vehicles on turning at high speed, minimize radius of turning of vehicles while doing sharp turning at low speed, and reduce spaces needed on parking motion. Four methods were used to study dynamics characteristics of a multi-function four-wheel steering system. Those four methods were method of constant yaw rate, method of equal side slip angle, method of zero side slip, and method of negative side slip or controlling side slip angle. The results of the study show that the method of zero side slip is the best method to determine rear wheel angle needed for a vehicle doing parking motion in order to minimize radius of turn. When a vehicle is turning at high or medium speed, rear wheel angle needed should be

Sutantra, I. Nyoman, Kaelani, Yusuf

A Theoretical Study on Front Steering Angle Compensation Control for Commercial Vehicles

2000-05-024406/12/2000

This study investigates a control strategy using the front steering angle control to improve the handling and stability of heavy-duty vehicles as a possible substitute for four-wheel steering (4WS) system. The effective steering input is regulated through the state feedback computed by the optimal control theory suggested in this research, to adapt the closed system to the changes of some factors depending on running situations, such as velocity and center of gravity. Direct moment control with a simple auto-tuning proportion controller is also integrated in the compensation system, wherein yaw moment and roll moment are applied to decrease side slip angle and roll angle respectively. A double-cost-function LQR methodology (DLQR) is developed to compute the value of the front steering angle compensation. In addition to traditional LQ cost function, another index called target cost function with a free form is introduced in DLQR to express physical requirements more plainly to determine

Jiang, Lan, Wang, Yuqing, Nagai, Masao

Lateral Stability Analysis of a 2 Degree-of-Freedom Vehicle Using a Time Lagged Lateral Tire Force Model

1999-01-079103/01/1999

In this paper fundamental analytical results for automobile lateral stability are developed. Specifically, the linear two degree-of-freedom, fixed steering control, front wheel steer and four wheel steer automobiles with a time lagged lateral tire force model is employed in the analysis. The stability conditions are derived using Routh Hurwitz criterion and Lyapunov’s method. The results are mainly algebraic in nature and examples are given demonstrating potential problems of front wheel and four wheel steering vehicles due to the time lag in the tire’s lateral force.

Samsundar, John, Huston, Jeffrey C.

A New Concept and Technology Used in a Powershift Transmission for Off-Highway Vehicles

97275009/08/1997

A new powershift transmission concept for specific market segments of backhoe loaders and telescopic boom handlers has been designed, thoroughly lab and field tested and is now in full production. This new transmission is identified as the T16000. The concept is a result of extensive market analysis, customer interviews and study of vehicle performance requirements. OEM requirements in terms of reliability and quality have been considered. New technologies such as electronic modulation for directional clutches and electric/hydraulic modulation of the range clutches have resulted in an excellent shift quality vis-a-vis to application requirements and/or driver preference. A special protection system (mechanical) integrated in the control valve protects the transmission from engaging two clutches at the same time, preventing a drivetrain lock-up. All sensors are integrated in the valve body and are totally sealed according to European Standard IP67 specification. Adaptive control

Pecceu, Hendrik

Rear Axle Steering System for Trucks and Buses

96218310/01/1996

Modern commercial vehicles must increasingly meet the requirements of economic efficiency, environmental protection, legislation and of the specific application. The Electronically-Controlled Rear Axle Steering System ZF RAS-EC™ makes an important contribution towards this and offers a basis for completely new approaches in the development of commercial vehicles.

Keller, Thomas, Kogel, Walter

Emulating the Lateral Dynamics of a Range of Vehicles Using a Four-Wheel-Steering Vehicle

95030402/01/1995

The concept of a Variable Dynamic Testbed Vehicle (VDTV) has been proposed as a tool to evaluate collision avoidance systems and to perform driving-related human factors research, among others. The goal of this study is to analytically investigate to what extent a VDTV with four-wheel-steering can emulate the lateral dynamics of a broad range of vehicle models. Using a particular mid-sized vehicle as a baseline, our study indicated that this mid-sized vehicle modelled with a closed-loop four-wheel-steering system can be controlled to emulate the lateral response characteristics of a range of vehicles, from “small” to “full-size,” reasonably well over a speed range of interest. A novel steering control configuration that has the potential to improve further the “degree of emulation” has also been proposed.

Lee, Allan Y.

Design of Two Wheel Steer Vehicle Using Optimal Control Algorithm of Four Wheel Steer

93191411/01/1993

Nonlinear and linear state equstions of 3 dof vehicle model for steering are derived by a symbolic computation software, MACSYMA. As these state equations are in symbolic form, the vehicle design variables for steering can be derived also in closed form. Then by putting the poles of the linear state equation to those of the optimal closed loop, an improved tunning of the vehicle steering response is obtained for two wheel steering vehicle.

Song, Jun-gyu, Yoon, Yong-San

Optimal Four-Wheel Steering Strategy Using Nonlinear Analytical Vehicle Models

93191511/01/1993

This paper presents a systematic methodology and formulation for determining optimal strategies for four-wheel steering of vehicles. The methodology is based on multibody dynamics, design sensitivity, and optimization techniques, and is applicable to a wide variety of mechanical systems. The particular application discussed in this paper considers a vehicle model with four-wheel steering capability, and the presented methodology determines an optimal steering angle ratio strategy for the vehicle. It is shown that such a strategy can improve the ride stability of the vehicle, during a variety of maneuvers, when compared against similar strategies obtained from linearized and simplified vehicle models.

Nikravesh, Parviz E., Lee, Jong-Nyun

Thin Film Strain Gauge Sensors for Automotive Applications

93035603/01/1993

We developed amorphous alloy thin films having TCR(temperature coefficient of resistivity) less than ±5 ppm/°C for strain gauge applications. Thin film strain gauges are directly formed on metal substrates insulated with SiO2. These gauges have excellent aging stability at high temperature. The resistivity shows a drift in ▵R/R less than ±0.03% at 120°C in 1000 hours. We developed a pressure sensor and an acceleration sensor with high accuracy and reliability, employing these gauges.

Kato, Yukihiro, Sumi, Chiaki

The Relationship between Vehicle Suspension and Steering System Design and Steering Behaviour

91257611/01/1991

Four wheel steering vehicle applied SATO's rear control logic is studied and compared with conventional vehicle via theoretical methods. Specially, the topic is discussed through eigenvalue sensitivity, frequency response and notion time history using simple model which has yaw and lateral motion freedom, and complicated model which is applied suspension derivatives, steering system flexibility and the non-linearity of tyre. Simulation studies are employed to test the validity of rear steer control logic which was designed on the basis of linear vehicle.

Kim, Chong Kap, Hwang, Han Ho, Kim, Yong Chil

Advanced Commercial Vehicle Steering Systems, Variants and Development Trends

91268711/01/1991

Better cost effectiveness, further improvement in ease of steering as well as energy advantages, with the safety standard as high as ever: these are the principal targets characterizing current and future developments in the field of steering systems for commercial vehicles. The relevant major development areas refer to single-circuit and dual-circuit steering systems with additional functions such as influencing by parameters. Steering systems for rear axles are another key development area.

Hughes, Robert A., Elser, Dieter

Development of Four Wheel Steering System Using Yaw Rate Feedback Control

91192209/01/1991

Toyota has succeeded in developing for mass production the active four-wheel steering(4WS) system using yaw rate feedback and steering angle feedforward control. The active 4WS system consists of a group of various sensors, including the newly developed yaw rate sensor, ECU, a rear wheel steering actuator that employs a stepping motor and hydraulic valve, and other hydraulic elements, which actively control the steering angle of the rear wheels. The new system ensures a good response and a high level of stabililty for quick steering wen during a high-speed drive. When the vehicle deflects due to a sudden side wind, road surface disturbance, or abrupt braking, steering is automatically corrected through the rear wheels to significantly improve forward stability. In addition, the! system prwides improved performance in making small radius turns because the rear wheels are steering up to five degrees when the front wheels are turned to a large angle. Also,improved vehicle maneuverability

Sato, Hiroki, Kawai, Hiroyuki, Isikawa, Masaru, Iwata, Hitosi, Koike, Shin

An Examination of the Maneuverability of an All Wheel Steer Vehicle at Low Speed

91024102/01/1991

With the goal of improving the driver's steering performance, the four(all) wheel steering(4WS) system was designed, and theoretical and experimental analysis of the 4WS system was investigated. In the 4WS system the low speed maneuverability is better due to a smaller turning radius. In reality, however, the opposite steering of the rear wheels could be counter-productive for certain maneuvers as shown in the Fig.1. In this paper, this counter-productivity is called the parking problem. The objective of this study is to prevent the parking problem and to maintain the maneuverability of the 4WS vehicle. To accomplish this goal, a new concept of the 4WS system for the low speed range has been introduced. It is proposed that the rear wheel steering angles should be zero for any front wheel steering angles at zero velocity and after the vehicle is started the real wheels should be steered to maintain their original direction for a moment before the rear wheel steering angle reaches the

Jung, Shinsub, Guenther, Dennis A.

A Multi-Axle Steering System for Straight Trucks

90225810/01/1990

A multi-axle (four-wheel) steering system for trucks and other commercial vehicles is described. The benefits of multi-axle steering and several examples of existing approaches are discussed. This leads to a set of defined goals for the subject design. The resultant design is described on a component and operational basis. Test results are analyzed to judge system performance. Finally, a discussion of concerns related to reducing the prototype to a manufacturable system is made.

Vaughn, B. K., Miller, L. L.

Nonlinear Dynamic Response of Four Wheel Steering Automobiles to Combined Braking and Steering Commands in Collision Avoidance Maneuvers

90173109/01/1990

A nonlinear “bicycle model” of an automobile was used to investigate both conventional front wheel (FWS) and four wheel steering (4WS) automobiles during emergency maneuvers combining braking with steering commands. The model includes a comprehensive, nonlinear tire model. Two different 4WS control laws were used. The first was an open loop law where the commanded rear wheel steer angle was based on the instantaneous front wheel steer angle. The second, a closed loop law, required a signal comprised of a comparison of yaw rate and front wheel steer angle to command the rear wheel steer angle. Simulated results of the response to combined hard steering and braking inputs the potential benefits of 4WS in these types of maneuvers - among these are faster and more stable response and improved maneuverability.

Xia, Xunmao, Law, E. H.

Four Parameter Evaluation Method of Lateral Transient Response

90173409/01/1990

There are many meaningful numerical evaluations of vehicle dynamic performance. However, evaluation methods using one or two parameters have little practical use for development of new cars or for comparison of similar cars since drivers' preferences vary widely in various handling characteristics. We developed the Four Parameter Evaluation Method. The parameters are extracted from lateral transient response data by curve fitting with a two degree of freedom model. Intuitively, we can recognize vehicle performance by arranging these four parameters in a rhombus. This expression is suitable for complex handling characteristics. The resulting rhombus pattern reflects a rather small difference between test cars including 4WS.

Mimuro, Tetsushi, Ohsaki, Masayoshi, Yasunaga, Hiromichi, Satoh, Kohji

IRVW Futura The Volkswagen Research Car

90175109/01/1990

The new research car of Volkswagen the IRVW Futura (IRVW = Integrated Research Volkswagen) is very compact, easy maneuverable, extremely economical in its fuel consumption and is outfitted with many components which enhance environmental compatibility, comfort and safety. Highlights of its technique are a direct injection gasoline engine as well as automatic parking ability, the information concept which offers the driver information in such a way that overtaxing is avoided, a child seat for children from three to eleven years of age which is an integral part of the normal rear seat and a speed dependent distance warning between the vehicle and the vehicle ahead.

Walzer, Peter, Grove, Hans-Wilhelm

Concept for Developing Vehicle Handling Evaluation Procedure Suitable for Active Control Technology

89120011/01/1989

The recent development of electronics has led to increased research efforts to put the active control technique to practical use in various fields of automotive technology. This report tries to identify the goals likely to be achieved by the active control technology and the subjects of study involved in research activities for this end. As a promising approach to the solution of these subjects, the report discusses the problem areas of the existing evaluation method for vehicle handling performance and then proposes feasible ideas in this field. Finally the report gives a few examples of the research methods we have successfully applied to the development of a four wheel steering system.

Sano, Shoichi, Furukawa, Yoshimi

Simulation of Dynamic Behavior of a Four Wheel Steering Vehicle by Means of a Vehicle and Driver Model

89007804/01/1989

A driver and vehicle model has been developed in order to analyse the transient behavior of a four wheel steering vehicle (4WS). The simulation of two driving situations (entering into a bend, and a sudden lane change test) shows that the control of the rear steering delay is necessary to optimize safety and efficiency during critical driving situations.

Landreau, Thierry

Items per page:

1 – 50 of 63