Application Study On A New Digital Electronicand Hydraulic Force Servo System Into AMT

Automated manual transmission (AMT) is a kind of automated transmission which is designed on the basis of the traditional transmission. It not only has the merit of high efficiency, low cost, easy to manufacture that the traditional transmission has, but also has the merit of easy operation and stable shift of what the automated transmission has. Therefore, it is worth making a research. Now, the automated manual transmission has two main types —electronic AMT and electronic-hydraulic AMT. The electronic AMT is easy to control, but its price is very high; while electronic-hydraulic AMT is complex in structure, can't adapt the change of the speed of transmission and unsmooth in gearshift. This paper presents a design of a new kind of electronic-hydraulic force servo AMT with electronic-hydraulic force servo system as the actuator. The electronic-hydraulic force servo system — digital servo rotary valve, is made up of the stepper motor, rotary valve and oscillation cylinder. Fixing the electronic-hydraulic force servo system on the gearshift fixes, we may control the shift of the transmission by controlling the system in order to complete the automatic transmission. After the detailed analysis of its structure, the paper presents the mathematical model of the electronic-hydraulic force servo system, and gives the analysis of its stability and response characteristics. The result is that the system is stable, rapid and smooth in response. In addition, the paper presents the design of the hardware and software of the control system, and uses the programmable controller (PLC) as the system's controller and writes the PLC control program.At last, to prove the validity of the program and to simulate the gearshift of transmission, the paper employs the communicating function of PLC and Kingview to carry out the simulating experiment of Kingview, and presents the stimulating curve of the angle - impulse.