Study On City Bus Green Driving Driver Assistance System Adapting To Horizontal Curves

Different driving behaviors lead to different fuel consumption, especially when the vehicle running through specific road segments such as horizontal curves, road ramps and traffic lights. Horizontal curves are typical section which widely distributed in the road. The geometric features of horizontal curves and the degree of drivers' sensitivity to a specific curve significantly affect the driver' driving behaviors and the states of the vehicle in the running process, which would result to higher energy consumption with the comparison of the process that the vehicle running on a flat and straight road. So this paper focuses on studying the connatural relationship between curves, driving behaviors and energy consumption. And explores the method to optimize driver's driving behaviors in order to save energy consumption when the vehicle running through a curve. The specific work of this paper mainly includes the following contents:More than 100000 kilometers' vehicle running data about six drivers on a bus line in Tianjin city was collected based on the vehicle remote monitoring system, and 28 horizontal curves data segments have been extracted. In addition, vehicle history position trajectory has been used to describe curve geometry line shape in an approximate way. Then we can calculate curvature of each point on the curve and predict the next curve parameters with CCS algorithm and road map service.A new method that using equivalent fuel consumption and kinetic energy contribution rate per unit fuel consumption was proposed to analyze the energy and fuel efficiency. Data analysis and statistic results show that with the same distance, the fuel and energy efficiency is different when a vehicle running through different types of curves. Especially for two evidently different horizontal curves, the fuel consumption difference is 10%. What's more, the fuel consumption difference is different according to the curve central angel, curvature and other curve geometry parameters. Study show that when two drivers drive a vehicle with the same configuration running through a curve and the fuel consumption difference is 33% when they get same kinetic energy increment.As for a further research, this paper studied the form of energy dissipation and explored the method of driving behaviors optimization in order to help drivers rectifying their improper driving habits adapt to a specific road horizontal curve. Fortunately, dynamic programming algorithm can be used for handling this multistep decision process optimization problem and two typical horizontal curves were selected as the dynamic programming experiment objects. Simulation experiments results show that the fuel consumption can be decreased by 7.69% and 27.51% for two horizontal curves after optimization.In addition,for the sake of fuel and energy saving in a real sense, green driving assistance system adapting to horizontal curves has been developed based on Android smart phone platform. This system can give drivers optimal vehicle speed advices and gear shifting suggestions with smartphone screen or voice prompt. Driver follows the suggestions and operate the vehicle according to traffic conditions may improve the energy efficiency when the vehicle running through a curve.