Research On Observer-based Fault Diagnosis For Twin Rotor Helicopter

The research object is a three degree of freedom (3-DOF) twin-rotor helicopter. In this paper,several fault diagnosis (FD) methods, based on state observer technology, are designed for the3-DOFtwin-rotor helicopter.Firstly, the research’s background, purpose and meaning are surveyed, also the concept of faultand the background of FD are described. The control principles of the tandem twin-rotor helicopterare discussed and the dynamic model of3-DOF twin-rotor helicopter is built. The software andhardware of3-DOF twin-rotor helicopter semi-physical platform are introduced. The open loopcharacteristic and closed loop characteristic of the system are analyzed to provide a basis for the FDmethods in next chapters.Secondly, this paper deals with the problem of fault diagnosis for a linear system with multipleactuator faults, and proposes a robust fast adaptive fault estimation algorithm based on robust H performance. For the case of multiple faults, the method is developed based on a suitable combinationof multiple model and adaptive observer.Then an adaptive sliding mode observer based FD method is proposed for a Lipschitz nonlinearsystem. The FD scheme can ensure that estimation errors of the fault and the state are bounded nomatter the fault is constant or it is time-varying. Then condidering that the observer matchingcondition is not satisfied, an auxiliary output vector is constructed using the knowledge of Differentialgeometry so that the observer matching condition is satisfied.Finally, the proposed FD methods in this paper are applied to the3-DOF twin-rotor helicoptersemi-physical platform. For the3-DOF helicopter control system model, the FD module is designed,and the MALTAB numerical simulation and the semi-physical simulation results indicate that theproposed FD methods are feasible and effective.