Multi Performance Optimal Shift Schedule For Automobile Driving On Curves

Shift schedule is one of the key technologies of automatic transmissions,and it is also one of the most crucial factors which can affect the performance of vehicles.When driving in a curve road the running of vehicles is no longer a straight line,a curve movement dynamic analysis was carried out on the vehicle,and centrifugal force,tire cornering properties,resistance increases,suspension deformation and vehicle safety driving speed etc should also be taken into account,all of which are out of consideration as vehicles are driving on the straight line.With all these differences,in this paper,based on the analysis of vehicle dynamic characteristics driving on the curve roads and the tire mechanical characteristics using the method of multi-objective optimization to calculate multi-performance optimal shift schedule for automobile driving on curves,concrete research content is as follows:(1)The technical characteristics of the common automatic transmission are summarized the development process of the shift schedule of automatic transmission is outlined;and the current research status has been summarized as well as the significance of this study.(2)A comprehensive analysis of the influence caused by curve situation is made.According to tire characteristics,vehicle dynamic characteristics and the current vehicle’s driving radius are used to determine the vehicle’s safe speeds on curves and compare the results with other scholar’s research results and conduct an experiment to verify.(3)Tire cornering properties and the tire adhesion limit under the combined effect of lateral force and vertical force are calculated according to the magic formula,taking the results as constraint conditions.Using the vehicle longitudinal dynamics to calculate vehicle longitudinal acceleration and take it as a performance evaluation index to construct dynamic objective function.(4)Neural network model of Engine power performance index and fuel consumption index are established by BP neural network.Build power performance objective function and fuel economy objective function,giving different weights to these two objective functions according to the driving demand,using linear weighted method to construct the comprehensive evaluation function;taking engine speed,vehicle safety driving speed,longitudinal acceleration,the ground adhesion as constraint conditions,the best shift points is obtained by genetic algorithm,thus determine the multi-performance optimal shift schedule for automotive driving on curve roads.(5)A simulation-based evaluation system for shift schedule is established using Matlab/Simulink.The simulation model of vehicle longitudinal dynamics and the ECE+EUDC driving cycle model has been built using MATLAB/Simulink/Stateflow platform.The formulated shift schedule has been evaluated through simulation results of dynamic performances and driving cycles.The simulation results shows that:the established shift schedules which are fitted to curve situation,although its fuel consumption increases slightly but can ensure traffic safety as well as effectively reduce the frequency of shifting.