Control System Design Of Mini Quard Tilt Rotor Aircraft

Tilt rotor aircraft combines the features of helicopters and fixed-wing aircraft,makes runway taxiing removed when taking off and landing, with the flexibility of thehelicopter, while is able to make high-speed and long-range cruise. The flight modesinclude helicopter mode, fixed-wing mode and transmition mode. As tiltrotor aircraftaerodynamic structures have both rotors and wings, leading the control system muchmore complex. So the Quard Tilt Rotor design has been proposed based on the bi-rotortilt rotor, which is greatly improved in terms of flight range, flight stability, payload,compared to conventional tiltrotor aircraft.Quard tilt rotor flight control system is designed in this paper. Firstly, theappropriate Axis systems are selected, and a simplified mathematical model of QTRisestablished, using the Newton’s classical mechanics. Then the control scheme underQTR each mode is analyzed and selected, the parameters of the controlled object’stransfer function are measured through experiments and the open-loop transfer functionof each channel is deduced. Based on analysis of the open-loop transfer function’sfrequency characteristics, the control law of each channel is designed using the classicalcontrol theroty, makeing the closed-loop system meet the design requirements, and isproved in Matlab simulink. Then the appropriate sampling frequency is selected tomake the controller discrete and digital controller easy to implement.Secondly, a mini QTR model is constructed as the filght control systemexperimental platform, the QTR hardware system and software processes are designed.Using ADuC7026as microcontroller, MEMS sensors, GPS navigation module,ultrasonic range finder as feedback components, the hardware system is built. And theflight control programs are coded to control each channel of QTR.Finally, a MEMS accelerometer is used for MEMS gyroscope angle compensation,in order to achieve higher detection accuracy. The flight control system is debugged andthe parameters of the system modified to make it fit the actual working condition, andmini QTR model to achieve autonomous vertical take-off and landing and the fixedheight stable hover.