Current Issue : July - September Volume : 2016 Issue Number : 3 Articles : 4 Articles
The phenomenon of car-following is special in traffic operations. Traditional car-following models\ncan well describe the reactions of the movements between two concessive vehicles in the same\nlane within a certain distance. With the invention of connected vehicle technologies, more and\nmore advisory messages are in development and applied in our daily lives, some of which are related\nto the measures and warnings of speed and headway distance between the two concessive\nvehicles. Such warnings may change the conventional car-following mechanisms. This paper intends\nto consider the possible impacts of in-vehicle warning messages to improve the traditional\ncar-following models, including the General Motor (GM) Model and the Linear (Helly) Model, by\ncalibrating model parameters using field data from an arterial road in Houston, Texas, U.S.A. The\nsafety messages were provided by a tablet/smartphone application. One exponent was applied to\nthe GM model, while another one applied to the Linear (Helly) model, both were on the stimuli\nterm ââ?¬Å?difference in velocity between two concessive vehiclesââ?¬Â. The calibration and validation were\nseparately conducted for deceleration and acceleration conditions. Results showed that, the parameters\nof the traditional GM model failed to be properly calibrated with the interference of\nin-vehicle safety messages, and the parameters calibrated from the traditional Linear (Helly)\nModel with no in-vehicle messages could not be directly used in the case with such messages.\nHowever, both updated models can be well calibrated even if those messages were provided. The\nentire research process, as well as the calibrated models and parameters could be a reference in\nthe on-going connected vehicle program and micro/macroscopic traffic simulations....
This research presents mathematical methods to develop a high-efficiency power train system for a micro electric vehicle (MEV).\nFirst of all, to get the optimal ratios of a two-speed gearbox, the functional relationship of energy consumption and transmissions\nis established using the design of experiment (DOE) and min-max fitting distance methods. The convex characteristic of the model\nand the main and interactive effects of transmissions on energy consumption are revealed and hill-climbing method is adopted to\nsearch the optimal ratios. Then, to develop an efficient and real-time drive strategy, an optimization program is proposed including\nshift schedule, switch law, and power distribution optimization. Particularly, to construct a mathematical predictive distribution\nmodel, firstly Latin hypercube design (LHD) method is adopted to generate random and discrete operations of the MEV; secondly\nthe optimal power distribution coefficients under various LHD points are confirmed based on offline genetic algorithm (GA);\nthen Gauss radial basis function (RBF) is utilized to solve the low-precision problem in polynomial model. Finally, simulation\nverifications of the optimized scheme are carried out. Results show that the proposed mathematical methods for the optimizations\nof transmissions and drive strategy are able to establish a high-efficiency power train system....
In this study, 2 DOF mathematical models of Pitman arm steering system are derived using Newton�s law of motion and modeled\nin MATLAB/SIMULINK software. The developed steering model is included with a DC motor model which is directly attached\nto the steering column. The Pitman arm steering model is then validated with actual Pitman arm steering test rig using various\nlateral inputs such as double lane change, step steer, and slalom test.Meanwhile, a position tracking control method has been used\nin order to evaluate the effectiveness of the validated model to be implemented in active safety system of a heavy vehicle. The\nsimilar method has been used to test the actual Pitman arm steering mechanism using hardware-in-the-loop simulation (HILS)\ntechnique. Additional friction compensation is added in the HILS technique in order to minimize the frictional effects that occur\nin the mechanical configuration of the DC motor and Pitman arm steering. The performance of the electronically actuated Pitman\narms teering system can be used to develop a firing-on-the-move actuator (FOMA) for an armored vehicle.The FOMA can be used\nas an active safety system to reject unwanted yaw motion due to the firing force....
Theintelligent vehicle is a complex system equipped with advanced technologies such as the artificial intelligence, automatic control,\nand computer, communication. It is a combination of multiple academic subjects and the latest technologies representing the\ndeveloping tendency of future automobile technology and attracts more and more attention. In this paper, we made some useful\nexplorations in the fields of intelligent vehicle control technology and obstacle avoidance, and a deep research is carried out about\nthe distance of vehicle, vehicle tracking, vehicle lane changing and intersections obstacle avoidance and communication protocols,\nand some innovative ideas are proposed during the research. By using VANET, some predictable status of tracing and tracking of\nintelligent vehicle technology was researched, and the communication protocols between two vehicles, the safe spacing algorithm,\nthe method of computing the actual distance at corners and straights, and the trajectory of lane change were designed. In addition, a\nseries of vehicle tracing and tracking technologies, such as without knowing the road conditions, homeostatic mechanism, keeping\na safe spacing to the target vehicle, and adjusting its own speed to track the target vehicle smoothly to the destination by comparing\nthe actual distance and safe spacing between vehicles, were discussed here....
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