Fault tolerant linear parameter varying flight control design, verification and validation

Design and aircraft‐in‐the‐loop validation of structured‐H∞ self‐scheduled fault‐tolerant controllers

“…Finally, also during the preliminary design efforts, it was deemed necessary to include a constraint on the overshoot of the response from r to u in the nominal system. This was combined with (11) to avoid over-exciting the actuators in the absence of faults. The maximum overshoot was selected as 5%.…”

“…Standard, no‐fault, Y$$$ {}^{\ast } $$$ control design objectives are: 11 [ Obj‐1 ] roll angle tracking with response time of less than 4 s and 0$$$ {}^{\circ } $$$ steady‐state error, [ Obj‐2 ] sideslip angle tracking with response time of less than 2 s and 0$$$ {}^{\circ } $$$ steady‐state error, [ Obj‐3 ] decoupled sideslip and bank angles responses to each others step commands with less than respectively $$$ \pm $$$0.05$$$ {}^{\circ } $$$ and $$$ \pm $$$0.5$$$ {}^{\circ } $$$, and [ Obj‐4 ] robustness to actuator time delays (see the ranges given in (2)) and airspeeds between [100, 200] knots.…”

“…For this reason, in this paper the term AIL is preferred over the more broad notion of HIL. For more details about MuPAL‐$$$ \alpha $$$, the reader is referred to References 11, 26, 27.…”

“…Manually scheduling, however, relies on heuristics and lacks theoretical guarantees and systematic design rules 10 . An alternative is to use the linear parameter‐varying (LPV) framework which provides a methodological way to schedule a controller, see for example, Reference 11 for an example of an LPV aircraft control design and validation against aileron and rudder faults, as well as 12 . More recently, an approach (equivalent in many aspects to the LPV method) has appeared based on a so‐called self‐scheduling extension of the structured H$$$ {}_{\infty } $$$ optimization technique 13,14 .…”

Sliding mode observers for robust fault estimation in linear parameter varying systems

“…The MuPAL‐$$$ \alpha $$$ Aircraft‐in‐the‐loop (AIL) platform 50 is currently used by the Japan Aerospace Exploration Agency to validate the performance of user‐defined advanced guidance and control laws and FDD/FTC methodologies for both ground AIL tests inside the hanger (see Figure 1), 51,52 and actual flight tests including Simple Adaptive Control, 53 $$$ {\mathscr{H}}_{\infty } $$$ Control, 23,54‐57 Sliding Mode Control (SMC) 11,44 and an Indirect Adaptive Control strategy involving online parameter estimation 58 …”