Benjamin Lussier

Fault diagnosis and fault-tolerant control strategy for rotor failure in an octorotor

This paper presents a fault tolerant approach for a coaxial octorotor regarding rotor failures. A complete architecture including error detection, fault isolation and system recovery is presented. The diagnosis system is designed with a nonlinear observer to generate residuals and an inference model to evaluate them and isolate the faulty motor. Once the motor failure is diagnosed, a recovery algorithm is applied. It uses the built-in hardware redundancy of the octorotor and compensates the loss of the failing motor by controlling its dual to keep a stable flight that allows the multirotor to continue its mission. This architecture is validated on real flights.

Actuator fault diagnosis in an octorotor UAV using sliding modes technique: Theory and experimentation

This paper presents a fault diagnosis strategy for actuators faults in an octorotor unmanned aerial vehicle (UAV) using sliding modes techniques. First, system states are estimated using a second order sliding-mode observer (SOSMO) based on the modified super-twisting algorithm. Second, faults are estimated by considering the system control as an unknown input. After the convergence of the observer, the equivalent output injection is used to estimate the unknown input and thus to identify losses in the actuators. The effectiveness of this approach is illustrated by numerical simulations on Matlab/Simulink, and also a real experimental application on a coaxial octorotor UAV.

A fault tolerant architecture for data fusion: A real application of Kalman filters for mobile robot localization

Abstract Multisensor perception has an important role in robotics and autonomous systems, providing inputs for critical functions including obstacle detection and localization. It is starting to appear in critical applications such as drones and ADASs (Advanced Driver Assistance Systems). However, this kind of complex system is difficult to validate comprehensively. In this paper we look at multisensor perception systems in relation to an alternative dependability method, namely fault tolerance. We propose an approach for tolerating faults in multisensor data fusion that is based on the more traditional method of duplication–comparison, and that offers detection and recovery services. We detail an example implementation using Kalman filter data fusion for mobile robot localization. We demonstrate its effectiveness in this case study using real data and fault injection.

Fault tolerant control for multiple successive failures in an octorotor: Architecture and experiments

This paper presents a fault tolerant control strategy based on an offline control mixing for an octorotor unmanned aerial vehicle (UAV) regarding several rotor failures. This strategy consists of a set of explicit laws, computed offline, each one dedicated to a fault situation. The corresponding law is selected according to the output of a fault detection and isolation (FDI) module. This module is designed with a non-linear sliding mode observer. The main advantage of this architecture is the deterministic character of the solution, its fast operation and the low computational load. The effectiveness of this approach is illustrated through real experimental application to a coaxial octorotor, where up to four motor failures are considered.

Controllability analysis and motors failures symmetry in a coaxial octorotor

This paper presents a fault tolerant control strategy for a coaxial octorotor regarding one motor failure. A controllability study, based on the construction of the attainable control set method, is presented for a coaxial octorotor with one or more failing motors. The fault is diagnosed using a non linear Super-Twisting sliding mode observer. The octorotor is recovered after a motor failure by controlling its dual motor. The effectiveness of this approach is illustrated by numerical simulations on an octorotor simulator.

Local controllability and attitude stabilization of multirotor UAVs

This paper addresses the attitude controllability problem for a multirotor unmanned aerial vehicle (UAV) in case of one or several actuators failures. The small time local controllability (STLC) of the system attitude dynamics is analysed using the nonlinear controllability theory with unilateral control inputs. This analysis considers different actuators configurations and compares their fault tolerance capabilities regarding actuators failures. Analytical results are then validated experimentally on a coaxial octorotor. A stabilization control law is applied on the coaxial configuration under one, two, three and four motors failures, when the system is controllable. Real-time experimental results demonstrate the effectiveness of the applied strategy. This paper addresses the attitude controllability problem for a multirotor UAV in case of actuators failures.The fault tolerance capabilities of different multirotor configurations are compared.Analytical results are validated experimentally on an octorotor UAV after up to four motors failures.

Fault Tolerance from Formal Analysis of a Data Fusion Mechanism

Multi-sensor perception systems are starting to be used incritical applications, such as in drones and ADAS (AdvancedDriver Assistance Systems). However, complete validation ofcomplex perception systems is difficult to achieve. In this paperwe examine these systems through the lens of an alternativedependability method, namely fault tolerance. We apply a formalanalysis on a belief function data fusion mechanism to providefault tolerance. By analyzing certain parameters related to thedata fusion process, we show that it is possible to offer faulttolerance services suitable for multi-sensor perception systems, including detection, recovery, and fault masking.

Passive fault-tolerant control of an octorotor using super-twisting algorithm: Theory and experiments

This paper presents the design and implementation of a Passive Fault-Tolerant Control (PFTC) strategy for a coaxial counter-rotating octorotor based on the Super-Twisting algorithm. This second-order sliding mode technique ensures robustness with respect to uncertainties and disturbances and is also able to deal directly with faults and failures by compensating the actuators loss in the system without prior knowledge on the fault, its location and its severity. The effectiveness of this PFTC is illustrated through real experimental application to a coaxial octorotor, where two motors failures are considered.

Model identification and validation for translational movements of an octorotor UAV

This paper presents preliminary results on a complete translational system modeling and identification of a coaxial counter-rotating X8 octorotor. The objective is to assess the applicability of the widely-used quadrotor model to the coaxial eight-rotor aircraft. A real and representative model of the UAV is necessary to develop simulation tools for validation and to predict the system behavior. A series of tests were conducted with the X8 in flight when performing movements in the x, y and z directions. The model is simulated and validated offline in a MATLAB environment using real data.