Fault detection and isolation on hydraulic systems are very important to ensure safety and avoid disasters. In this paper, a fault detection and isolation method, based on the flatness property of nonlinear systems, is experimentally applied on the three-tank system, which is considered as a popular prototype of hydraulic systems. Specifically, fault indicators, called residues, are generated using flat output measurements, and for the purpose of fault isolation, a definition of the isolability is introduced. This definition allows the characterization of flat outputs that are useful for fault isolation. A sensitivity analysis is proposed in order to improve the robustness of the method. Multiplicative faults are considered on sensors and actuators.
This paper presents our initiative on the design and building of a convertible aircraft for fault tolerant control. The main advantage of convertible over conventional aircraft is that they can take-off and land vertically, practically eliminating the need for a long runway. At the same time, fixed wings allow to improve energy efficiency with respect to multi-copters. To satisfy these objectives, we have chosen a bi-rotor delta-wing design which is described in the first part of the paper. The paper gives a description of the main educational activities of this project emphasizing its multidisciplinary nature. Indeed, one important aspect of this project is that we have had the chance to work with students from various specialities (such as mechanical engineering, embedded systems, avionics and automatic control) on bachelor and master’s levels. Moreover, the end result of this project should provide us with a very interesting experimental test-bench for teaching and research purposes. Finally, this activity is also the opportunity for our students to develop their soft skills such as project management and communication.
This paper describes the dynamic modeling of a vertical take-off and landing (VTOL) aircraft and shows the flatness of the proposed model. Flat systems have the property that the inputs and the states can be written as functions of a set of the system outputs (called at outputs) and the derivatives of these at outputs. The flatness property allows to compute an inverse dynamic model of the given system. This can be used in path planning, nonlinear control and fault detection and isolation. The convertible aircraft presented in this paper uses redundant actuators. The advantage of this design is twofold. Firstly, it is possible to configure actuators to optimize both stationary and fast horizontal flight. Secondly, in case of one actuator failure, it provides sufficient flexibility to reconfigure the actuators in order to land safely. An important contribution of this paper is the demonstration of the flatness property for the proposed dynamical model of the convertible aircraft.