Study On Intelligent Control Method For Shift Schedule Saving Energy Of Engineering Vehicle

As a kind of special vehicle, engineering vehicle possesses very important status in vehicle family. The complexity of the operation, the badness of working conditions, the variety of working tasks and the frequent gear-shifting of the drivers result in high labor intension and low working efficiency in which it is difficult to maintain high driving efficiency. In order to solve the problem of the low efficiency of transmission system, it is urgent to adopt automatic transmission technology to engineering vehicle to adapt specific working environment and improve vehicle performance. This Ph.D. dissertation developed under the project (No.59705005) named "engineering vehicle electronic control for saving energy"supported by National Natural Science Foundation of China and Backbone Teacher Foundation of Ministry of Education, DOCTOR Foundation project (No. 20020183003): Study on Automatic Shift Technology with Four-parameter of Engineering Vehicle. This paper aiming at the characteristics of hydro-mechanical transmission, GA-RBF (Genetic Algorithms Optimize Radial Basis Function Neural Network ) control technology is employed to design automatic gear-shifting strategy of engineering vehicle based on the discussed energy-saving shift-decision. The intelligent control system on automatic transmission of engineering vehicle is built up so that the controlled vehicle can adapt automatically to the working condition and the outer load by means of being endowed with intelligentized action. And furthermore, GA-RBF optimizing algorithm, which inherits neural network control technology's excellence, is introduced to improve the precision and respond speed of the control system so that it is possible that the system works with higher efficiency. Supported by Matlab/simulink, simulation research on automatic transmission system of engineering vehicle is carried through. Electronic control unit(ECU)of automatic transmission is developed with the design and debugging of the hardware and software of control system. Finally, a testing experiment on test-bench of transmission system is carried out to validate the availability of control algorithm and test the integrated performance of automatic transmission control system. Following is the introduction about every chapter of the dissertation. In chapter one, the development trends of oversea and inland vehicle's automatic transmission are introduced according to the phylogeny of automatic transmission technology and the application productions of the technology in construction machinery are emphasized. Referring to the current situation of our country, the important significance of adopting automatic transmission on engineering vehicle is discussed. It has been made clear that AT technology is the necessity to the development of human civilization and socialization. The conventional engineering vehicle with hydrodynamic transmission is renovated with AT technology. By introducing the composing and principle of ECU and all kinds of intelligent control methods, it can obtain the conclusion that intelligentizing is developing trend of automatic transmission. It is urgent to develop an integrated intelligent control technology to solve more and more complicated control problems. Finally, the main contents are made certain based on the research results of the predecessor. In chapter two, the mathematical models of the hydro-mechanical transmission system of engineering vehicle are set up. The attribute and structure of the transmission system are firstly introduced. And, by means of theory analysis and experimental data, the mathematical models of engine, torque converter, engine-converter matching working, power gear-shifting transmission, bodywork and driving conditions and etc are figured out in detail. On the base, the kinetic equation of vehicle running is brought forward. In theory, the works above is a good preparation for the subsequent computer simulation of automatic transmission control of engineering vehicle and even the whole study. Summing up the methods of solving low efficiency of toque converter anciently. At last main contents of this dissertation is set forth. In chapter three, the Shift Schedule are discussed. Theoretic research of engineering vehicle automatic transmission is the key of this chapter. Firstly, the automatic transmission control system for vehicle is expatiated and the aims, tasks and performance evaluation guidelines are ascertained. The working principle of electro-hydraulic control system and its hydraulic system for automatic transmission, which is widely applied oncurrent engineering vehicle, is specially emphasized. Then, the automatic shifting schedule of engineering vehicle are studied in which the characteristics and application range of single-parameter, double-parameter, three-parameter and four-parameter gear-shifting strategy is made a summary. The influence of automatic transmission technology on the performance of vehicle is discussed from driving feature, fuel economy, power-train efficiency and shift quality aspects. Energy saving shift schedule which can maintain the power-train working at the range of high efficiency is discussed. And the control method of energy saving shift schedule are given. Then, discussed the problem of shift delay. At last, intelligent control system of automatic transmission is designed. On the theoretical base and implemental method, it is discussed systematically how the technology of GA-RBF is applied to automatic gear-shifting control of hydro-mechanical transmission for engineering vehicle. This is the main part of the dissertation. The neural network control model of automatic transmission for engineering vehicle is put forward by artificial intelligence control theory. To get effective learning algorithm and overcome the defects of BP neural network which has the slow convergence speed and can not jump out of the local minima, the GA-RBF optimization method based on neural network is proposed to improve the optimization process of network structure parameters. Spreading all over, randomicity and regularity characteristics of GA-RBF movement are made full use of to come into being a GA-RBF neural network having strong learning capability. By training a great deal samples, the validity of the learning algorithm based on GA-RBF put forward is proved. Finally, the GA-RBF control scheme for automatic transmission and evaluation method for the efficiency of transmission system are perfected. In chapter four, the computer simulation of automatic transmission system is carried out. The computer simulation is one of important measures developing intelligent control on automatic transmission for engineering vehicle. Supported by Matlab/Simulink, the mathematic models set up in the chapter two can be translated into the computer models including driver model, powertrain model, working conditions model, GA-RBF gear-shifting controller model, bodywork model and so on. And then, SIMULINK toolbox of simulation software MATLAB is employed to carry through testing analysis and work out the results of simulation. The results show:simulation models set up, working conditions selected and original parameters designed are logical, which effectivelyvalidates the validity of optimal driving shifting rules as well as the feasibility, veracity and reliability of the structure and control algorithm for intelligent gear-shifting control system. Through simulative experiment, it is confirmed basically exterior and interior information the gear-shifting control system need. So, the simulation can find out the problems that must be solved when control system is designed, provide parameters for the practical design of system and change the control configuration in time. In chapter five, the control methods analyses of improving shift quality are discussed. The causes of shift impact and value indexs of impact level in shift course are analyzed, the control methods improving shift quality of engineering vehicle automatic transmission system are proposed such as installing accumulator, throttle cushion control and the timing control of adjusting enforce machine overlap time etc. In chapter six, the electronic control system for automatic transmission based on GA-RBF control technology is designed and developed. This part is material research process of realize intelligent gear-shifting control on engineering vehicle. According to the system running demands and the computer simulation results mentioned above, the total design idea and development mode is illuminated. The advantage of system design consists in its mechatronics design idea. In the chapter, the function design is finished after having understood the working principle of ECU so that the exploitation way of the whole system can be made certain. And then, taking TMS320LF2407A DSP as control core of ECU, its main performances and interior resources are introduced. The structure of hardware, selection of electronic elements and designs of some representative function circuits is concretely explained. Finally, on the base, the structure of software adopting module design idea and the flowsheet of main controlling programs are carried out with some anti-interference schemes in the process of developing electronic control system. The gear-shifting delay is employed to figure out the repeating shift problem so as to ensure that microprocessor control on automatic transmission is exact. The ECU exploitation provides substantial condition for the performance test of AT system. In chapter seven, an experimental study for automatic transmission system and the characteristic analysis of executive machine for gear-shifting are accomplished. This chapter is a practice to complete research. An experiment on the test-bench for hydro-mechanical transmission is carried out aiming at to prove the feasibility of automatic gear-shifting strategy, GA-RBF control algorithm, simulative results and design schemeof ECU mentioned above as well as to test the whole performance of automatic transmission controller. The final goal is to check if the working capability of control system meets the design demands. The experiment consists of two parts: self-learning tests and control tests, the former is designed to prove the performance of the intelligent control algorithm and model to automatically acquire working conditions of vehicle, from which gear-decision is made, while the latter is planned to test the integrated capability of automatic transmission system by means of the knowledge acquired in self-learning experiment. At the same time, the experimental results are output and the conclusions are analyzed. Finally, the future development trends of automatic transmission control technology on vehicle are prospected. The results of experiment show that the control system for automatic transmission can achieve self-learning to working conditions and exterior changes according to working samples provided with wheel loader. Through modifying GA-RBF structure parameters, the shift schedule with the energy saving can be obtained. On the other way, these shifting strategies above are employed to carry through gear-decision, which can realize the optimization of gearbox's gear, namely, reach control aim——saving energy. Chapter eight is the summary of the whole dissertation, and the main research achievements and innovative discovers are expatiated. Suggestion and prospect of automatic transmission research are given.