In the domestic commercial vehicle market, there is an increase of demand on the automated multistep manual transmission but the study and development on the transmission have not proceeded further yet. As a result, the transmission has been entirely imported from overseas suppliers by paying high cost and it is applied to the commercial vehicles. Therefore, on this study it’s expected that the study of shifting control logic, which is the core technology in the automated manual transmission, contributes to the industry in the domestic market.
Study method and scope have been defined and analyzed through the benchmarking of overseas suppliers’ automated manual trans- mission. And with these analysis results, study orientation of shifting control logic on automated manual transmission has been set up as the final goal. After the requirements of shifting control logic have been defined through the detail study and data analysis on the transmission system operation and actuator control, each S/W module was constructed in order to do control and signal conditioning applying model-based S/W development method for the requirements of automated manual transmission control. S/W module has been developed as three modules which are shifting control logic, clutch control module, and shifting actuator control module. For each module, SILS(Software In the Loop Simulation) has been performed and its designed results have been checked and updated. And shifting timing setup of shifting control logic, which is the main topic on this study, has been designed with artificial intelligence techniques instead of shifting map which is applied according to Loop-up table type. The test of the designed S/W has been performed and checked on test bench with functions of multistep automated manual transmission after integrating both high level layer S/W, which is shifting control logic, and low level layer S/W, which is firmware and device driver, into TCU. And after installing automated manual transmission built with TCU in the high performance commercial vehicle, the driving test has been performed under chassis dynamometer and the acquired data from test has been checked and analyzed. With the analyzed results, it has been checked whether or not control logic requirements are consistent. And after evaluating satisfaction status of control performance target, it was confirmed that the additional study was needed.
At this research from analysis of requirements to chassis dynamometer test, the study results came out as follows.
First, torque relation at each gear-shifting was confirmed via modeling results of multistep automated manual transmission. And contents for control logic and transmission operation were analyzed with data from TCU connected with sensors, solenoid valves, and CAN communication through benchmarking. With these analyzed results, specification and design target were defined to implement TCU S/W.
Second, shifting control logic and shifting map based on fuzzy control algorithm were designed for 12 speed shifting control system of automated manual transmission and clutch control system applying model-based S/W development method. The designed shifting control logic and intellectual gear-shifting map were applied to TCU S/W and satisfaction of the design target was confirmed through SILS and vehicle test using chassis dynamometer.
Thirds, in particular the design of gear-shifting map using fuzzy control algorism consists of up shifting timing and down shifting timing by throttle and gear-step inputs. In vehicle driving test on chassis dynamometer, analysis results of up and down shifting timing indicated that shifting performance was superior to shifting map applied with look-up table. Thus, the design target was satisfied.
Evaluation on shifting control logic and shifting map based on fuzzy control algorithm was done under condition of normal driving mode on chassis dynamometer. Therefore, many tests and evaluations on chassis dynamometer and on real road are indeed required after applying shifting control logic and shifting map on TCU S/W. And the various studies are continually done in order to improve and solve the error and problem of shifting control logic and shifting map given from the test results.