A Robust Control Approach for Fault Tolerant Control of a Multicopter

Improving the safety of multicopters is of great interest due to the various applications they could offer if they can demonstrate their robustness to failures. Fault Tolerant Control (FTC) techniques can enable these vehicles to continue to operate safely in case of failure in the propulsion system. In this paper, a H-infinity robust control design on fixed-structured output feedback with integral action for multicopter vehicles is presented. An optimization process is performed to synthesize a passive FTC. Position and attitude control gains are tuned by using first the non-faulty model, then multiple models to consider the plant in case of the complete loss of one motor. A comparison is achieved with an active FTC, which reconfigures the control allocation according to the Fault Detection and Diagnostic (FDD). The most significant finding is that the proposed control strategy is successful in keeping the vehicle to operate safely in the event of an actuator loss without the need to detect the failed motor. This work also underlines the need to consider handling quality criteria in the controller design process for applications that involve passengers or narrow environments.