| On the basis of the traditional mechanical transmission, AMT(Automated Mechanical Transmission) which can implement the separation and engagement of clutch and automatic control of shifting is formed by removing the clutch pedal,the manual shifter and installing microcomputer control system. Among technologies of AMT, clutch control whose performance directly affects the performance of AMT is the core one. In view of this, the AMT electric clutch control system is researched in this paper and the following aspects are included:Firstly, diaphragm spring clutch was selected as the object. The working characteristics of the clutch were studied. The elastic properties model of the diaphragm spring clutch was established. The clutch torque transmission model was established. The clutch engagement process was analyzed. The dynamics of clutch system was researched. The best engaging law of clutch engagement process was determined. Then a subsection control scheme was proposed. In the semi-engagement stage, in order to reduce the engagement impact, the clutch was engaged as the maximum engagement speed which was determined by the limit of jerk. In other two stages, the clutch was engaged as the maximum engagement speed which was determined without the limit of jerk.Secondly, worm gear and gear rack were selected as transmission program according to the design requirements of actuator. Parameters for each component were designed. Then all parts of clutch and electric actuator 3D models were conducted in UG 8.5. Working principle of brushless DC motor was studied. The BLDCM was selected as the driving motor. The technical parameters of the motor were determined. The mathematical model of the motor was established according to its working principle. Finally, the mathematical model of the entire electric actuator was established.Thirdly, the PID control algorithm was studied. The integral separation PID control method was put forward for the control of engagement speed. The speed controller and current controller were designed. The electric clutch control system model was established in MATLAB/Simulink. Taking the engagement process as an example, the control system simulation was conducted. The simulation result shows that the control system has a good dynamic response. The engagement velocity and position are tracked accurately. It meets the control requirements very well.Finally, in order to verify the effectiveness of the designed control system, DS1401 processor and I/O DS1505 board were selected as the dSPACE simulation platform. The structure and principle of the hardware circuit were studied. The control system model was established based on Simulink and RTI. The real-time control code was generated in RTW. The control system model was debugged in Control Desk. A rapid control prototyping experiment was conducted. The result shows that the designed controller meets control requirements well especially for clutch engagement speed and displacement. |
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