Study On Road Identification And Shift Schedule Correction Method For Powertrain

Tracked vehicle road condition is complex, there are dirt roads, grass, snow, swamp, mountain and natural or artificial barriers such as trenches, trapezoidal obstacles, running resistance varies greatly. Present on the tracked vehicle commonly used two-parameter shift schedule based on the accelerator opening and the vehicle speed, the premise solve the shift schedule is steady engine test data, belong to static category, poor ability to adapt to the external environment, cannot guarantee that the vehicles are always in the best gear, influence the best performance of the vehicle. Therefore, this article conducted a study to identify road conditions and the shift schedule correction method of the powertrain.Conducted a correction method based on the powertrain shift control vehicle load ratio and the change rate of engine speed research, the basis of the research is two parameters dynamic shift schedule. In the correction method based on the powertrain shift control vehicle load ratio study, by defining zero load ratio and full load ratio of the two conditions for vehicle load ratio is defined. A shift point correction method based on vehicle load ratio is proposed which can dynamic modify the shift point according to the current environment to meet the dynamic needs of different driving resistance. In the study of powertrain control method based on the shift correction in the rate of change of engine speed, Analysis of the powertrain when traveling on the complex road, traveling resistance changes will cause the engine speed changes, respectively based on Fourier transform and threshold complex road analysis and identification. Based on the analysis and identification of pavement where the Fourier transform is mainly the change rate of engine speed signal from the time domain to the frequency domain. Advantage of [15.40] Hz frequency interval signal energy proportion in the total energy used to determine the road roughness. Pavement complex analysis and recognition based on threshold is to analyze the change rate of engine speed signal in the time domain features, Established a real-time algorithm complex processes of identifying road based on threshold law, to identify the current road conditions by the counter value N of each cycle road roughness level. A shift point correction method based on road roughness level is proposed which can dynamic modify the shift point.Correction method for powertrain shift controlling based on the vehicle load ratio in MATLAB / Simulink environment with a constant slope conditions typical vehicle driving cycle track offline simulation. A Hardware-in-the-loop simulator based on the driving cycle conducted a bench test based on fixed slope conditions. For the powertrain shift controls based on the rate of change of engine speed correction methods were offline simulations of complex road fixed throttle, Analysis the data of vehicle test and make the offline simulations. Proven the powertrain shift control based on the vehicle load ratio and the rate of change of engine speed correction methods of the identification of the external environment is relatively accurate. Amendments shift points and torque converter lock point is valid, effectively solve the circle transmission of tracked vehicle under some conditions.