Application of rack type motor driven power steering control system for heavy vehicles

The Electric Power Steering (EPS) or Motor Driven Power Steering (MDPS) mechanism proves to be a bright prospect among passenger vehicles ensuring better vehicle safety and fuel economy. The car manufacturers are focusing on the production of Rack type EPS system (REPS). This paper describes the development of concurrent simulation technique using TruckSim and control strategy for analysing RMDPS control system with a dynamic vehicle system. A full Truck vehicle model interacting with RMDPS control algorithm was concurrently simulated on a sinusoidal steering input. The dynamic responses of vehicle chassis and steering system resulting were evaluated and compared with proving ground experimental data. The comparisons show reasonable agreement on steering wheel torque, lateral acceleration and yaw rate. This concurrent simulation research leads the possibility of RMDPS performance evaluation of Truck and Semi-bonnet cars.     

Simultaneous detection of the nonlinear restoring and excitation of a forced nonlinear oscillation: an integral approach

We address in this article, how to calculate the restoring characteristic and the excitation of a nonlinear forced oscillating system. Under the assumption that the forced nonlinear oscillator has a periodic solution with period \(T=2\pi / \omega\), we constructed a system of linear equations by introducing time-dependent multipliers. The periodicity assumption helps simplify the system of linear equations. The stability and uniqueness are also presented for the inverse problem. Numerical testing is conducted to show the effectiveness of our presented methodology.     

城市轨道交通赢利能力分析

轨道交通以其运量大、速度快、时间准、污染少、安全舒适，且与城市道路无平面交叉等优势，自20世纪以来成为备受各国青睐的交通方式。如拥有1000万人13的巴黎，轨道交通承担了70％的公共交通量；莫斯科和香港轨道交通承担了55％的城市客运量；东京的轨道交通占公共交通量的80％以上。     

Characterizing Driver Stress Using Physiological and Operational Data from Real-World Electric Vehicle Driving Experiment

Electric Vehicle (EV) is becoming a viable and popular option, but the acceptance of the technology can be challenging and lead to an elevated driving stress. The existing studies on stress of vehicle driving has been mainly limited to the non-EVs or survey analysis. In this research, EV driving data of 40 subjects is analyzed, where each subject was asked to drive an EV over a 53 km course in a suburban city of South Korea. Physiological data including electroencephalogram (EEG) and eye-gazing were obtained along with vehicle operational data such as state of charge, altitude, and speed. The dataset was rich in information, but individual difference and nonlinear patterns made it extremely difficult to draw meaningful insights. As a solution, an information-theoretic framework is proposed to evaluate mutual information between physiological and operational data as well as the entropy of physiological data itself. The result shows two groups of subjects, one not showing much evidence of stress and the other exhibiting sufficient stress. Among the subjects who showed sufficient driving stress, 9 out of the top 10 high EEG-entropy drivers were female, one driver showed a strong pattern of range anxiety, and several showed patterns of uphill climbing anxiety.     

A minimization theory in Hilbert space and its application to two-dimensional cavity flow with a numerical study

A minimization theory, which is based on the Hilbert space theory, is proposed and applied to two-dimensional cavity flow past a strut with the assumption of potential flow. That is, the minimization of the cavity drag of the strut on the cavity flow is studied with the help of the optimization theory proposed. To accelerate the optimization process, the Euler beam theory is introduced to generate a small variation in the strut. The introduction of the Euler beam theory makes the mathematical formulation for the present theory ill-conditioned. To overcome this condition, the Tikhonov regularization and the Morozov's discrepancy principle are used to regularize the present optimal theory. From the numerical study, it is shown that the proposed minimization theory is able to find an optimized shape for the given strut and corresponding optimized cavity drag. Received: June 22, 2000 / Accepted: January 30, 2001     

Use of 3D compartment model for simplified full ship FE model. Part I: construction of FE model

Classification societies cannot cover the torsional strength assessment with simple empirical formula as the size of a containership increases drastically over 10 000 TEU in recent years. Torsional strength of a container ship is very difficult to estimate with an analytical method due to its alternatively varying cross sections, i. e. an open and a closed section. This article proposes an approach to construct a simplified FE model using a 3D compartment model available from the beginning of ship design process. The model is cut to pieces of lots of small pieces of lines by a set of transverse, longitudinal and horizontal planes. Two algorithms are developed for mesh generation of internal structures; one for assembling the broken lines into closed loops and the other for automatically generating mesh from the loops. Another algorithm is proposed to generate mesh for outer hull using outermost nodes of the FE model built for internal members. The validity of the simplified model is discussed along with a beam theory based approach in J Mar Sci Technol (2008)     

Development of the Lane Keeping Control System Using State-Varying Surface for Vulnerable Road Users

This paper proposes a new Lane Keeping Assist (LKA) system based on the integrated control strategy with AFS and BTV. To be specific, the steering controller calculates the gear ratio of AFS to align with the target lane whereas the braking controller determines differential brake pressure using Sliding Mode Control (SMC) theory according to the state-varying sliding surface with Fuzzy model. In recent years, auto industries have produced the lane keeping applications to prevent lane departure caused by drivers’ distractions or drowsiness. To also prevent wrist injury in drivers while steering, current LKA systems limit the output values of steering-wheel assist torque. This limiting mechanism, however, can cause a problem that cannot follow a road curvature when an older driver overexerts an inappropriate control effort. A new LKA system of the AFS and BTV integrated controller has since been drafted to solve this problem, and validated its performance in regards to the test conditions given with various driver models.     

Lateral handling improvement with dynamic curvature control for an independent rear wheel drive EV

The integrated longitudinal and lateral dynamic motion control is important for four wheel independent drive (4WID) electric vehicles. Under critical driving conditions, direct yaw moment control (DYC) has been proved as effective for vehicle handling stability and maneuverability by implementing optimized torque distribution of each wheel, especially with independent wheel drive electric vehicles. The intended vehicle path upon driver steering input is heavily depending on the instantaneous vehicle speed, body side slip and yaw rate of a vehicle, which can directly affect the steering effort of driver. In this paper, we propose a dynamic curvature controller (DCC) by applying a the dynamic curvature of the path, derived from vehicle dynamic state variables; yaw rate, side slip angle, and speed of a vehicle. The proposed controller, combined with DYC and wheel longitudinal slip control, is to utilize the dynamic curvature as a target control parameter for a feedback, avoiding estimating the vehicle side-slip angle. The effectiveness of the proposed controller, in view of stability and improved handling, has been validated with numerical simulations and a series of experiments during cornering engaging a disturbance torque driven by two rear independent in-wheel motors of a 4WD micro electric vehicle.     

Dual influences on vehicle speed in special-use lanes and critique of US regulation

We verify that slow speeds in a special-use lane, such as a carpool or bus lane, can be due to both, high demand for that lane and slow speeds in the adjacent regular-use lane. These dual influences are confirmed from months of data collected from all freeway carpool facilities in the San Francisco Bay Area. Additional data indicate that both influences hold: for other types of special-use lanes, including bus lanes; and for other parts of the world.The findings do not bode well for a new US regulation stipulating that most classes of Low-Emitting Vehicles, or LEVs, are to vacate slow-moving carpool lanes. These LEVs invariably constitute small percentages of traffic; e.g. they are only about 1% of the freeway traffic demand in the San Francisco Bay Area. Yet, we show: that relegating some or all of these vehicles to regular-use lanes can significantly add to regular-lane congestion; and that this, in turn, can also be damaging to vehicles that continue to use the carpool lanes. Counterproductive outcomes of this kind are predicted first by applying kinematic wave analysis to a real Bay Area freeway. Its measured data indicate that the site selected for this analysis stands to suffer less from the regulation than will others in the region. Yet, we predict: that the regulation will cause the site’s people-hours and vehicle-hours traveled during the rush to each increase by more than 10%; and that carpool-lane traffic will share in the damages. Real data from the site support these predictions. Further parametric analysis of a hypothetical, but more generic freeway system indicates that these kinds of negative outcomes will be widespread. Constructive ways to amend the new regulation are discussed, as are promising strategies to increase the vehicle speeds in carpool lanes by improving the travel conditions in regular lanes.     

The smoothing effect of carpool lanes on freeway bottlenecks

Real data show that reserving a lane for carpools on congested freeways induces a smoothing effect that is characterized by significantly higher bottleneck discharge flows (capacities) in adjacent lanes. The effect is reproducible across days and freeway sites: it was observed, without exception, in all cases tested. Predicted by an earlier theory, the effect arises because disruptive vehicle lane changing diminishes in the presence of a carpool lane. We therefore conjecture that smoothing can also be induced by other means that would reduce lane changing.The benefits can be large. Queueing analysis shows that the smoothing effect greatly reduces the times spent by people and vehicles in queues. For example, by ignoring the smoothing effect at one of the sites we analyzed one would predict that its carpool lane increased both the people-hours and the vehicle-hours traveled by well over 300%. In reality, the carpool lane reduced both measures due to smoothing. The effect is so significant that even a severely underused carpool lane can in some instances increase a freeway bottleneck’s total discharge flow. This happens for the site we analyzed when carpool demand is as low as 1200 vph.