System identification for fault tolerant control ofunmanned aerial vehicles

[摘要] ENGLISH ABSTRACT: In this project, system identification is done on the Modular Unmanned Aerial Vehicle(UAV). This is necessary to perform fault detection and isolation, which is partof the Fault Tolerant Control research project at Stellenbosch University.The equations necessary to do system identification are developed. Various methodsfor system identification is discussed and the regression methods are implemented.It is shown how to accommodate a sudden change in aircraft parametersdue to a fault. Smoothed numerical differentiation is performed in order to acquiredata necessary to implement the regression methods.Practical issues regarding system identification are discussed and methods foraddressing these issues are introduced. These issues include data collinearity andidentification in a closed loop.The regression methods are implemented on a simple roll model of the ModularUAV in order to highlight the various difficulties with system identification. Differentmethods for accommodating a fault are illustrated.System identification is also done on a full nonlinear model of the Modular UAV.All the parameters converges quickly to accurate values, with the exception of Cl R,CnP and Cn A. The reason for this is discussed. The importance of these parametersin order to do Fault Tolerant Control is also discussed.An S-function that implements the recursive least squares algorithm for parameterestimation is developed. This block accommodates for the methods of applying theforgetting factor and covariance resetting. This block can be used as a stepping stonefor future work in system identification and fault detection and isolation.

[发布机构] Stellenbosch University