Research On Fault Diagnosis And Tolerance Control For A Multi-faulty Quad-rotor System

Quad-rotor is a kind of multi-rotor aircraft, which has a lot of advantages, such as simplestructure, vertical take-off and landing ability. In both military and civil fields, it has importantapplication value. However, due to the over-actuated and strong coupling characteristics of theattitude control system, as well as the problem of data transmission and fault correlation, thus in thewhole system of quad-rotor, it is hard to locate faults and ensure the accuracy and efficiency of faultdiagnosis. Especially, when more than one malfunctions happen in different parts, the crosstransmission of multi-fault makes fault diagnosis worse. Therefore, the multi-fault diagnosis andtolerant control have been a hot research topic of multi-rotor helicopter system. This thesis, aiming atthe multi-malfunction in actuators of quad-rotor attitude control system, discusses fault diagnosis andtolerant control technology. Research achievements in this thesis have offered a useful thought toimprove the security and reliability of the helicopter system.The main contributions of this thesis canbe summarized as follows:Firstly, in this thesis, the developments of fault diagnosis, tolerance control and the quad-rotorare reviewed, these features of structure and control of the quad-rotor are analyzed, and then itsmathematical model is given. Furthermore, based on these classical fault types and modes of actuators,the fault model of the quad-rotor is established.Secondly, with the help of the established quad-rotor fault system, as well as considering thecross transmission of multi-actuator fault and the traditional model-based fault diagnosis technology,a control mode with divided channels is built, two fault diagnosis strategies based on multi-observerand limited frequency domain, respectively, are designed, which effectively avoid the couplingcompact and achieve the goal of accurately detecting and locating the multi-fault.Further, taking the fault tolerant ability of the system into account, a kind of active fault tolerantcontrol algorithm is proposed, which helps make fault and disturbance in different frequency domain,with the aid of General Kalman-Yakubovich-Popov (GKYP) Lemma, satisfy these correspondingperformance requirements, so that the control system can remain stable and maintain a good flightperformance after fault happens.Finally, these methods mentioned above are totally applied to the three degrees of freedomquad-rotor half-physical simulation platform, and stimulation results verify the feasibility and validity.