Active fault tolerant control for general aircraft using NLGA

The aerospace applications are considered among one of most complex. The non-linear dynamics and coupling within aircraft systems remains a challenging research area for long time till date. The faults and failures are ordinary in all electrical/mechanical sub-systems. The probability of occurrence can be debatable but it is impossible to assume fault free systems. The faults in input actuators in aircraft can be fatal and highly undesirable. There is a need to make aircraft remain safe/operational and stable in case of such undesirable event. This goal can only be achieved using fault tolerant controls FTC, and in this case active fault tolerant control system AFTCS methodology is considered and investigated. The fault detection and diagnosis FDD can provide the basis of AFTCS. The accurate and effective FDD is explored using Non-linear Geometric Approach (NLGA) for non-linear dynamics of aircraft. In addition, the criticality of descent/landing phases is not unknown since accidents are more prone to happen during these phases. The backstepping (BS) control scheme is proposed as a non-linear method to achieve glide slope control system. The proposed control scheme provided sound tracking performance. The FDD module in combination with BS based control system, provided AFTCS which is capable of stabilizing the aircraft and achieving the desired performance in both scenarios, i.e. faulty/faultless. Minor performance degradation is present but comfort/workload of pilot remains similar to faultless system since aircraft recovers nominal condition promptly, post-fault occurrence. The robustness analysis is satisfactory.