Current Issue : October - December Volume : 2014 Issue Number : 4 Articles : 5 Articles
Yaw stability control system plays a significant role in vehicle lateral dynamics in order to improve the vehicle handling and stability performances. However, not many researches have been focused on the transient performances improvement of vehicle yaw rate and sideslip tracking control. This paper reviews the vital elements for control system design of an active yaw stability control system; the vehicle dynamic models, control objectives, active chassis control, and control strategies with the focus on identifying suitable criteria for improved transient performances. Each element is discussed and compared in terms of their underlying theory, strengths, weaknesses, and applicability. Based on this, we conclude that the sliding mode control with nonlinear sliding surface based on composite nonlinear feedback is a potential control strategy for improving the transient performances of yaw rate and sideslip tracking control....
We have developed a method ofmanaging vacancy information of a large parking lot in a distributed manner using only intervehicle\ncommunication. A group of parking spaces is defined as a cluster.Vacancy information of a cluster is managed by a vehicle in it.This\nvehicle is called a cluster head.The proposedmethod generates a communication path topology between cluster heads.Thetopology\nis a tree structure with the cluster head of the cluster nearest to the parking lot entrance as the root node. Cluster heads are ranked\nin order of the number of vacant spaces and the distance to the shop entrance. The vehicle entering the parking lot collects vacancy\ninformation of clusters. This information is transmitted along the tree structure from the lowest ranking cluster head. We have\ndeveloped a simulation model for a parking lot that can accommodate nearly 1,000 vehicles and used it to evaluate the proposed\nmethod. We have confirmed that the proposed method generates less communication traffic and enables the vehicle entering a\nparking lot to collect vacancy information about the area near the shop entrance with a higher probability and in a shorter time....
We propose an approach for themodeling and analysis of two connected traffic intersections based on Petri nets (PNs).We first use\na PN to model an isolated four-way signalized intersection; then we extend it to model two successive signalized intersections.We\nfind that this model has unbounded places, which in turn results in some confliction problems. Hence, we introduce the concept of\nmodified binary petri nets (MBPNs) to overcome the limitation and resolve the confliction problem when we design ourmodel and\nits controller. ThisMBPNmodel is a powerful tool and can be useful for themodeling and analysis of many other traffic applications....
We investigated the impact of deregulating the presence of stop signs at railway crossings on car driver behavior.We estimated the\nprobability that a driver would stop inside the crossing, thereby obstructing the tracks, when a lead vehicle suddenly stopped after\nthe crossing and a stop regulation was eliminated.We proposed a new assessment method of the driving behavior as follows: first,\ncollecting driving behavior data in a driving simulator and in a real road environment; then, predicting the probability based on\nthe collected data. In the simulator experiment, we measured the distances between a lead vehicle and the driver�s vehicle and the\ndriver�s response time to the deceleration of the leading vehicle when entering the railway crossing.We investigated the influence of\nthe presence of two leading vehicles on the driver�s vehiclemovements.Thedeceleration datawere recorded in the field experiments.\nSlower driving speed led to a higher probability of stopping inside the railway crossing. The probability was higher when the vehicle\nin front of the leading vehicle did not slow down than when both the lead vehicle and the vehicle in front of it slowed down. Finally,\nadvantages of our new assessment method were discussed....
This paper discusses a concept for enhanced active safety by introducing a driver warning system based on vehicle dynamics\nthat predicts a potential loss of control condition prior to stability control activation. This real-time warning algorithm builds\non available technologies such as the Electronic Stability Control (ESC). The driver warning system computes several indices based\non yaw rate, side-slip velocity, and vehicle understeer using ESC sensor suite. An arbitrator block arbitrates between the different\nindices and determines the status index of the driving vehicle.The status index is compared to predetermined stability levels which\ncorrespond to high and low stability levels. If the index exceeds the high stability level, a warning signal (haptic, acoustic, or visual)\nis issued to alert the driver of a potential loss of control and ESC activation. This alert will remain in effect until the index is less\nthan the low stability level at which time the warning signal will be terminated. A vehicle speed advisory algorithm is integrated\nwith the warning algorithm to provide a desired vehicle speed of a vehicle traveling on a curve. Simulation results and vehicle tests\nwere conducted to illustrate the effectiveness of the warning algorithm....
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