Fault Tolerance Of A Flexible Manipulator

Abstract

This paper presents an application of a sensor fault tolerant control (FTC) scheme on a flexible joint and flexible link. A linear observer is used to reconstruct the faults. Then the reconstruction is subtracted from the faulty sensors to form a `virtual sensor' and this signal (instead of the normally used faulty output) is then used to generate the control input. This minimizes performance degradation. A design method to make the virtual sensor insensitive to system uncertainties is presented. Two fault conditions are tested; total failure and incipient faults. Then the robustness is tested by implementing the joint's FTC scheme on the link. Excellent results have been obtained for both cases; the FTC scheme caused the system performance is almost identical to the fault-free scenario, even for simultaneous faults.