Research On Key Control Technique Of Brushless Direct Current Electric Actuator

As the actuator of flight control system, the rudder loop working performance and reliabilitydirectly determines the flight quality and safety of an aircraft. Based on the rudder loop controllerplatform put up by resolution elements, this thesis will extend research on rudder loop’ object-orientedmodeling, control law design, failure analysis and processing as well as controller software’s designand development, etc.At first, based on the summery of the present laboratory research situation and problems ofbrushless DC rudder loop project, this thesis elaborates the key technology and the key problemsneeded to be solved. According to the sample rudder loop control and reliability requirements, itestablishes control law, typical fault characteristics and detailed indicator for the interface to flightcontrol computer communication.Secondly, through detailed analysis of brushless DC motor working principle, it established themathematical model of the steering engine and commutation torque ripple models upon differentinverter bridge drive mode. Then it manages to design three closed loop control law strategy (position,speed, current) and the best inverter bridge single chop driving mode. Under the Matlab environment,It conducts the simulation test verification and iterative optimization for closed loop PID controlparameters, with the fruitful result of optimized controlling parameter.Thirdly, according to the typical failure analysis of brushless DC rudder loop, it extends researchon fault characteristics and features. According to the research, the paper designs two kinds of faultprocessing scheme based on current self-test and six-phase brushless DC motor. According toinformation exchange demand between rudder loop and flight control computer, it manages to designcommunication protocol based on CAN.At last, from the above research achievements, this thesis designs and exploits rudder loopcontrol software and applicatin software, with the achievement of control, communication and controldisplay for brushless DC rudder loop. On the experiment platform of Brushless DC rudder circuit, itcomprehensively tests the system’s function and performance. The test result verifies the validity ofthe design’s control law, fault handling, communication protocol and embedded software, and alsolaid a solid foundation for the engineering application of brushless DC rudder loop.