Control of Pneumatic Actuator for Automated Mechanical Transmission Dry Friction Clutch Base on the Pulse Width Modulation Signal

To ensure quality of dry friction clutch engagement in automated mechanical transmission during vehicle starting-up and maneuvering the control range of clutch actuator has to be maximum wide. It depends on the consistency of the clutch actuator geometric parameters with the electrical characteristics of the used solenoid valves, the output stage of the controller and the PWM control signal frequency. In addition to precision electronic control the driver must be able to “manually” operate the dry friction clutch in emergency. That is why friction clutch must have two independent control circuits. The original automated drive with a duplicate pneumohydraulic circuit for the friction clutch is presented in the paper, as well as the research results of the PWM frequency influence on operating range of the clutch pneumatic actuator. The research was based on the analysis of semi-natural experiment for assessing the functional performance of the designed automated mechatronic control system for the truck mechanical transmission. Ecomat R360 controllers were used as a hardware base of the test bench information control system. The developed software for the controller with one-parameter feedback on the clutch release lever movement allows to provide the PWM signal of varying duty ratio to the proportional solenoid valve of the automated drive. A graphical representation of the research results was performed with visualization possibilities of CoDeSys V2.3. During the semi-natural experiment, the polynomial dependence between variation of the clutch actuator control range and the generated PWM signal frequency in the range up to 400 Hz was revealed as well as practical recommendations on the choice of the optimum PWM signal frequency are also given in activity. The research results can be used in an adaptive control algorithm for automated mechanical transmission of trucks and road trains to ensure precise control of the clutch actuator in the starting-up and maneuvering processes.