Browse Topic: Four wheel steering

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Bike with Modified Steering System to Assist People with Forearm Disability2018-28-00627/9/2018
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 System2018-01-06974/3/2018
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 tracking tasks.
Huang, Chao, Naghdy, Fazel, Du, Haiping
The Trajectory Planning of the Lane Change Assist Based on the Model Predictive Control with Multi-Objective2017-01-20049/23/2017
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 lane change assist based on the model predictive control with multi-objective is then studied. The influence of vehicle speed on trajectory tracking is analyzed in this paper, then the feasibility and robustness of the algorithm is verified. In addition, the complexity of the model is simplified in considering of real-time demand while accuracy is still guaranteed. Simulation and experimental results show that the trajectory planning algorithm based on the model predictive control with multi - objective has greater improvements of those objectives of lane change compared with PID control. The proposed trajectory optimization algorithm can provide reference for the automatic lane change assist system.
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 Control2017-01-15683/28/2017
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 constraints can be achieved. As a case study the effects of over-actuation on the cornering resistance were investigated in two different maneuvers i.e. step steer and sine with dwell, where in both cases the vehicle assumes to be in steady state situation. In this work the cornering resistance is the main objective function and maintaining the reference trajectory is the constraint which should be fulfilled. A parameter study is conducted on the benefits of over-actuation, and depending on the type of over-actuation about 15% to 50% reduction in cornering resistance were observed during step steer and sine with dwell maneuver respectively. From a second parameter study that focused on COG position from a safety perspective, it is more beneficial for the vehicle to be designed to under-steer than over-steer. Finally, a method is described to translate the offline optimal results to vehicle implementable controllers in the form of both feed-through lookup-tables and rule-based feed-forward control.
Bhat, Sriharsha, Davari, Mohammad Mehdi, Nybacka, Mikael
Robust Control of a Four-Wheel-Independent-Steering Electric Vehicle for Path Tracking2017-01-15843/28/2017
Compared with the traditional front-wheel- steering (FWS) vehicles, four-wheel-independent-steering (4WIS) vehicles have better handing stability and path-tracking performance. In view of this, a novel 4WIS electric vehicle (EV) with steer-by-wire (SBW) system is proposed in this paper. As to the 4WIS EV, a linear quadratic regulator (LQR) optimal controller is designed to make the vehicle track the target path based on the linear dynamic model. Taking the effect of uncertainties in vehicle parameters into consideration, a robust controller utilizing μ synthesis approach is designed and the controller order reduction is implemented based on Hankel-Norm approximation. In order to evaluate the performance of the designed controllers, numerical simulations of two maneuvers are carried out using the nonlinear vehicle model with 9 degrees of freedom (DOF) in MATLAB/Simulink. Simulation results show that the robust controller is superior to the LQR optimal controller in tracking accuracy in terms of the nominal vehicle model. Furthermore, the robust controller can make the vehicle track the target path well under the circumstances of different vehicle velocities and road friction coefficients, which indicates the robust controller has strong robust stability and good robust performance against parametric perturbations.
Hang, Peng, Chen, Xinbo, Luo, Fengmei, Fang, Shude
Big-Data Based Online State of Charge Estimation and Energy Consumption Prediction for Electric Vehicles2016-01-12004/5/2016
Whether the available energy of the on-board battery pack is enough for the driver’s next trip is a major contributor in slowing the growth rate of Electric Vehicles (EVs). What’s more, the actual capacity of the battery pack depend on so many factors that a real-time estimation of the state of charge of the battery pack is often difficult. We proposed a big-data based algorithm to build a battery pack dynamic model for the online state of charge estimation and a stochastic model for the energy consumption prediction. And the good performance of sensors, high-bandwidth communication systems and cloud servers make it convenient to measure and collect the related data, which are grouped into three categories: standard, historical and real-time data. First a resistance-capacitance ( RC )-equivalent circuit is taken consideration to simplify the battery dynamics. And the nonlinear relationship between the open-circuit voltage (Voc ) and the state of charge ( SOC ) is described by five linear piecewise functions, achieving good fitting effect and accuracy. The moving window recursive least square algorithm is utilized to identify the parameters of the battery model online with the historical and real-time data. A Luenberger state observer is used for online estimation of SOC, the estimation accuracy of which is not dependent on the actual capacity’s value. Afterwards, giving more insight into the relationship between the received data from different sources and the estimated SOC, we take the objective law of energy consumption as a Gaussian distribution, which can provide the confidence interval analysis to confine decision-making about whether to have the trip to the driver.
Zhang, Zhiyun, Huang, Miaohua, Chen, Yupu, Gao, Dong
Automotive Engineering: March 3, 201616AUTP033/3/2016
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 Architecture 2017 Porsche Boxster loses cylinders, gains power, adds frugality 2016 Mini Clubman's torque-vectoring AWD system designed to give 2wd efficiency
Driving and Steering Coordination Control for 4WID/4WIS Electric Vehicle2015-01-27629/29/2015
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 show that the proposed integrated chassis controller is able to improve the vehicle's stability and handling performance through coordinating the steering and driving systems.
Li, Chunshan, Song, Pan, Chen, Guoying, Zong, Changfu, Liu, Wenchao
Development and Control of Evasive Steer Assist Using Rear Wheel Steering2015-26-00041/14/2015
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. Linear threat assessment and path planning followed by optimal control of the trajectory in combination with driver steering shows a significant improvement in collision avoidance by steering. A test vehicle Mondeo is equipped with rear wheel steering is tested at different vehicle speed for collision avoidance against stationary and moving obstacles. A set of metrics are created to show the performance improvement against the base design of the vehicle.
Shah, Jitendra
Study on Dynamic Characteristics and Control Methods for Drive-by-Wire Electric Vehicle2014-01-22919/30/2014
A full drive-by-wire electric vehicle, named Urban Future Electric Vehicle (UFEV) is developed, where the four wheels' traction and braking torques, four wheels' steering angles, and four active suspensions (in the future) are controlled independently. It is an ideal platform to realize the optimal vehicle dynamics, the marginal-stability and the energy-efficient control, it is also a platform for studying the advanced chassis control methods and their applications. A centralized control system of hierarchical structure for UFEV is proposed, which consist of Sensor Layer, Identification and Estimation Layer, Objective Control Layer, Forces and Motion Distribution Layer, Executive Layer. In the Identification and Estimation Layer, identification model is established by utilizing neural network algorithms to identify the driver characteristics. Vehicle state estimation and road identification of UFEV based on EKF and Fuzzy Logic Control methods is also conducted in this layer. In the Objective Control Layer, a real-time ideal reference model of vehicle dynamics for drivers with different characteristics are built up with Radical Basis Function (RBF) neural network by using the driving simulator test data, which is used for the control objective of the UFEV. In the forces and motion distribution layer, the control objective (resultant forces and moment of the vehicle) is converted to a constrained optimization control problem, the optimized objective function can be chosen according to different goals, such as the maximum tire-force margin, the minimum energy consumption, then, solving the optimization problem and send the distributed forces and motions to each actuator (e.g. longitudinal tire forces and steering angles of four wheels). Simulation and experimental verification show that the systematic solution proposed in this paper are effective for the UFEV.
Zhang, Dong, Zong, Changfu, Chen, Guoying, Song, Pan, Zhang, Zexing
Research on Integrated Chassis Control Strategy for Four-Wheel Independent Control Electric Vehicle2014-01-22909/30/2014
Four-wheel independent control electric vehicle is a new type of x-by-wire EV with four wheels independent steering and four wheels independent drive/brake systems. In order to take full advantage of the vehicle's performance potential, this paper presents a novel integrated chassis control strategy. In the paper, the strategy is designed by the hierarchical control structure and divided into integrated control layer and allocation layer. By this method, the control logical can be modularized and simplified. In the integrated control layer, Model Prediction Control (MPC) is adopted to design the integrated control unit, which belongs to be a kind of local optimization algorithm with feedback correction features. Using this method could avoid the system performance degradation caused by the control model mismatch. The control allocation layer is to optimally distribute the vehicle control forces to the steering/driving/brake actuators on each wheel. In order to maximize the use of the tire adhesions, the algorithm sets the tire load rate minimized as the control target. Finally, based on the four-wheels-independent vehicle dynamic model, the feasibility of the proposed integrated chassis control strategy is verified under the condition of step steering angle response with two different road adhesion coefficients.
Chen, Guoying, Zhang, Dong
An Innovative Design Concept of Four Wheel Steering Mechanism for an Automobile2013-01-284511/27/2013
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 wheel, rear wheel and four wheels. The paper deals with the mechanical steering system which can perform all these operations. The paper presents a new design of steering system which involves a connector, coupler and bevel gears. In a front wheel steering, only front wheels steer, and in a rear wheel steering only rear wheels will steer to get turning. In a four wheel steering system at low speeds, the front wheels and rear wheels are out of phase for low turning radius. However at high speeds, the front and rear wheels should be in phase to increase the stability of a vehicle. The paper presents a single steering mechanism arrangement offering three modes of steering operations possible which can be selected by the driver.
Vanamala, Uma Maheshwar, koganti, Raja Rao
Pump Controlled Steer-by-Wire System2013-01-23499/24/2013
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 energy-saving technology, pump displacement control, which eliminates throttling losses associated with hydraulic control valves by controlling the displacement of a variable displacement pump. This new architecture lends itself to high energy efficiency resulting in lower fuel consumption and reduced emissions, higher machine productivity and reduced operator fatigue, and active safety functions that counteract instabilities and reject disturbances.
Daher, Naseem A., Ivantysynova, Monika
Active Yaw Control of a Vehicle using a Fuzzy Logic Algorithm2012-01-02294/16/2012
Yaw rate of a vehicle is highly influenced by the lateral forces generated at the tire contact patch to attain the desired lateral acceleration, and/or by external disturbances resulting from factors such as crosswinds, flat tire or, split-μ braking. The presence of the latter and the insufficiency of the former may lead to undesired yaw motion of a vehicle. This paper proposes a steer-by-wire system based on fuzzy logic as yaw-stability controller for a four-wheeled road vehicle with active front steering. The dynamics governing the yaw behavior of the vehicle has been modeled in MATLAB/Simulink. The fuzzy controller receives the yaw rate error of the vehicle and the steering signal given by the driver as inputs and generates an additional steering angle as output which provides the corrective yaw moment. The results of simulations with various drive input signals show that the yaw stability controller using fuzzy logic proposed in the current study has a good performance in situations involving unexpected yaw motion. The yaw rate errors of a vehicle having the proposed controller are notably smaller than an uncontrolled vehicle's, and the vehicle having the yaw stability controller recovers lateral distance and desired yaw rate more quickly than the uncontrolled vehicle.
Ghosh, Simanta, Deb, Anindya, Mahala, Manoj, Tanbakuchi, Morteza, Makowski, Matthew
A Comparative Study of Active Control Strategies for Improving Lateral Stability of Car-Trailer Systems2011-01-09594/12/2011
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 variable geometry approach (VGA) has been investigated. The essence of this method is to actively control the lateral displacement of the car-trailer hitch in order to improve high-speed stability of the vehicle system. To derive the three controllers, their respective yaw plane models are introduced. The simulation results based on each control method are examined and compared against each other. Through the benchmark comparisons, the features of different control strategies are identified and their applicability discussed.
Shamim, Rafay, Islam, Md Manjurul, He, Yuping
Integrated Control of Active Steering and Electronic Differentials in Four Wheel Drive Vehicles2009-01-04464/20/2009
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 combined lateral and longitudinal tire forces. In response to sudden direction changes the simulations show reduced oscillations, robustness and enlarged bandwidth for the yaw rate tracking dynamics while new stable maneuvers are allowed especially in critical conditions such as μ-split braking.
Marino, Riccardo, Scalzi, Stefano
Modeling and Simulation of a Hydraulic Steering System2008-01-270410/7/2008
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 the loop testing. The simulation results verify the functions and performance of the hydraulic steering system.
Yuan, QingHui, Xie, Bo
Fault-Tolerant Architecture of Yaw Moment Management with Steer-by-Wire, Active Braking and Driving-Torque Distribution Integrated Control2008-01-01104/14/2008
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 wider use of SBW systems in a near future.
Hayama, Ryouhei, Higashi, Masayasu, Kawahara, Sadahiro, Nakano, Shirou, Kumamoto, Hiromitsu
The Co-simulation of Steering and Suspension System with ADAMS&Matlab/Simulink2007-01-36668/5/2007
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
Development of Electric Active Stabilizer Suspension System2006-01-15374/3/2006
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 Systems2005-01-357311/1/2005
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 Systems2005-01-12754/11/2005
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 Applications2003-01-01993/3/2003
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 with delta-sigma (Δ∑-) modulation in closed or open loop control is implemented into ASICs, the communication between the sensor elements and the internal microcontroller takes place via a SPI-interface. Internal logical links and self monitoring, CAN-interface between the Sensor Cluster and the ECUs and the possibility of internal redundancy for high safety-relevant, high dynamic and performance systems meet the future requirements. Design, basic functions, modular concept, safety features and system requirements of the new Inertial Sensor Cluster DRS MM 3.x are presented.
Willig, R., Mörbe, M.
Two Motor Electric Axle2002-01-19196/3/2002
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
Robust Controller Design for Automatic Steering of Vehicles2001-01-332310/1/2001
This paper deals with the controller design problem for automatic steering of vehicles. The nonlinear and uncertain lateral motion model of the vehicle is considered. The sliding mode controllers, with LQ optimal sliding surface and with guaranteed cost sliding surface, are proposed such that the lateral velocity and the yaw rate are stabilized. The robustness of the controllers is verified by comparing the simulation results.
Zhang, J. R., Rachid, A., Xu, S. J.
A Coordination Approach for DYC and Active Front Steering2001-01-12753/5/2001
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 concept2000-05-03526/12/2000
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 system2000-05-02456/12/2000
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 determined by method of negative side slip angle. A multi-function, four-wheel steering system could improve directional stability, sharp turning performance, and parking performance of a vehicle.
Sutantra, I. Nyoman, Kaelani, Yusuf
A Theoretical Study on Front Steering Angle Compensation Control for Commercial Vehicles2000-05-02446/12/2000
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 reasonable weighting matrices. The DLQR extends the concept and the applicable field of LQR to solve an optimal control problem with a general nonlinear cost function. The simulation results show that the integrated system significantly improves the steering characteristics to produce the desired vehicle response in various running conditions.
Jiang, Lan, Wang, Yuqing, Nagai, Masao
Lateral Stability Analysis of a 2 Degree-of-Freedom Vehicle Using a Time Lagged Lateral Tire Force Model1999-01-07913/1/1999
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 Vehicles9727509/8/1997
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 algorithms that consider oil temperature and other parameters that change during the life of the product (e.g. wear) are integrated and assure long term stability of shift quality and comfort.
Pecceu, Hendrik
Atacama Desert Trek: A Planetary Analog Field Experiment9724877/1/1997
Nomad, a planetary-relevant mobile robot, is chartered to traverse 200 kilometers across the Atacama Desert in Chile, exploring a landscape analogous to the surfaces of the Moon and Mars. Operating both autonomously and under the control of operators thousands of kilometers away, Nomad and the Desert Trek address issues of robotic configuration, communications, position estimation and navigation in rugged, natural terrain. The field experiment also serves as a testing ground for remote geological investigation, paving the way for new exploration strategies on Earth and beyond. Finally, by combining safeguarded teleoperation with onboard panoramic visualization and a novel user interface, the Atacama Desert Trek provides the general public an unforgettable interactive experience and its first opportunity to remotely drive an exploratory robot. An unprecedented demonstration, the Atacama Desert Trek sets a new benchmark in high performance robotics operations relevant to terrestrial and planetary exploration.
Whittaker, William Red, Bapna, Deepak, Maimone, Mark W., Rollins, Eric
Rear Axle Steering System for Trucks and Buses96218310/1/1996
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 Vehicle9503042/1/1995
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.
Optimal Four-Wheel Steering Strategy Using Nonlinear Analytical Vehicle Models93191511/1/1993
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 Applications9303563/1/1993
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
ISG (Integrated Starter/Generator)9201582/1/1992
The object with this paper is to give performance data for an ISG (Integrated Starter/Generator) which is mounted around the flywheel. With regard to weight, the ISG concept shall be competitive compared to a system with conventional components. The comparison will be based on a 48 V DC-system, and performed for a vehicle which is heavily equipped with electrical loads. The paper focuses on the electrical machine in the ISG (which is of induction type). The convertor is only covered in brief. For design of the start system, a computer program for simulation of a start sequence is used. Models implemented in the program will be discussed. A simplified equation for the load torque during cranking will be explained. For design of the generator system, two different drive cycles will be discussed. One is more related to the traditional load-balance situation during city driving, and the other related to the new load-balance obtained with the characteristic of an induction machine. The results will indicate dimensions of a flywheel-mounted ISG which is competitive with conventional technique.
Kristiansson, Urban
The Relationship between Vehicle Suspension and Steering System Design and Steering Behaviour91257611/1/1991
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 Trends91268711/1/1991
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 Control9119229/1/1991
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 at low speed is obtained.
Sato, Hiroki, Kawai, Hiroyuki, Isikawa, Masaru, Iwata, Hitosi, Koike, Shin
An Examination of the Maneuverability of an All Wheel Steer Vehicle at Low Speed9102412/1/1991
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 limit of the rear wheel steering angle. Under this new concept, the 4WS system vehicle was investigated. The results show that the new 4WS system reduces the parking problem and maintains the maneuverability of the vehicle.
Jung, Shinsub, Guenther, Dennis A.
A Multi-Axle Steering System for Straight Trucks90225810/1/1990
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.
Four Parameter Evaluation Method of Lateral Transient Response9017349/1/1990
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 Car9017519/1/1990
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
Nonlinear Dynamic Response of Four Wheel Steering Automobiles to Combined Braking and Steering Commands in Collision Avoidance Maneuvers9017319/1/1990
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.
Concept for Developing Vehicle Handling Evaluation Procedure Suitable for Active Control Technology89120011/1/1989
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 Model8900784/1/1989
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
Steering System of a Lifting Robot Vehicle and its Dynamic Performance8900974/1/1989
Paper illustrates a steering system of a lifting robot vehicle which is used for assembling and disassembling the active wheel of blower mill in power station. The whole steering system is controlled by a microprocessor. The axles of the four wheels are driven hydraulically. Proportional valves, which are controlled by the output signals of microprocessor calculated from the rotation angle of steering wheel, are used to control the flow into the cylinder. The step response of the system is calculated by digital simulation and the calculated result is compared with the experimental result, They are close to each other.
Shichang, Zhou, Xinming, Cao, Chenrui, Gao, Entao, Zhou, Jiancheng, Zhang, Donghai, Su
General Instrument AUTOLAN™- A High Speed Multiplexing System for Automotive Body Wiring Systems8905412/1/1989
AUTOLAN is a Class C multiplexing system suitable for use with realtime control systems. It fully conforms to the SAE Multiplex Subcommittee's proposed definition of a Class C system in that: Repetitive and Bursty data transfers are possible Handshaking can be implemented More than 10 Nodes can be handled Latency less than 5 millisecond Bus rate 4 Mbits/sec It can be used as a Class B system to provide data communication between microprocessor controlled assemblies. It can be used as a Class A system to replace the conventional body wiring harness. The transmission media is a dual twisted pair cable. Shielding may be required in extreme radiant field conditions, such as may be found in electric traction systems with a power rating greater than 500 HP. AUTOLAN does not require a microprocessor at each Node. Rather, for Class C, the system microprocessor drives the AUTOLAN network, whose nodes act as its remote I/O ports. And for Class A and B, a single microprocessor at a Master node is dedicated to running the network.
Harris, John D. H., Bailey, Nigel M.
Multiple Steered Axles for Reducing the Rollover Risks of Heavy Articulated Trucks88186610/1/1988
This paper presents an analytical study of the performance improvements that can be obtained at both high and low speed using multiple steered axles on heavy articulated trucks. At high speed, rollover usually represents a worst case scenario. Therefore we have chosen to evaluate possible steering designs based on their ability to reduce lateral acceleration of the semitrailer center of gravity. This is in contrast to passenger cars where four-wheel steering has typically been evaluated based on measures that were thought to be related to driver acceptance. This paper also investigates the effects of steering rear tractor axles on the low-speed maneuverability of the vehicle. Steering algorithms for the rear tractor tires were evaluated using frequency response and simulation of an obstacle avoidance maneuver. Results indicate that at high speeds considerable reductions in trailer lateral acceleration can be obtained during transient maneuvers. At low speeds, steering of the rear axles demonstrated improvements in maneuverability. More work is needed to determine if drivers are able to effectively make use of these improvements indicated by the open loop models, and to evaluate the practicality and cost of implementing these systems.
Furleigh, D. D., Vanderploeg, M. J., Oh, C. Y.
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