Aircraft flat-spin recovery using sliding-mode based attitude and altitude control

Abstract

In the present paper, a control command to recover steady-straight-level flight from flat-oscillatory-stable-left-spin is developed using a sliding-mode based attitude and altitude control. Direct spin recovery, using a spin solution by bifurcation results, to low angle-of-attack is achieved in finite-time without any separation in dynamics. The exponential convergence of errors is discussed by invoking Barbalat’s Lemma theorem. Thereafter settling time is obtained thereby making the system a finite-time stable to reach the sliding surface. The novelty of this work lies in the proposed control strategy, wherein expressions for all four primary control inputs are obtained in a closed-loop form without any approximation and altitude margin required for flat-spin recovery is investigated based on a heuristic approach for a fixed controller gains. Additionally, results of this research indicate the proposed controller first stops the spin by controlling the attitude of the aircraft thereby rotation stops about the body axis and then reaches the commanded altitude to attain the horizontal flight.

Adaptive neural network sliding mode control of a nonlinear two‐degrees‐of‐freedom helicopter system

“…According to Barbalat lemma [36], $$$ \underset{t\to \infty }{\lim}\left[\kappa {s}^Ts+\eta {\left\Vert s\right\Vert}_1\right]=0 $$$ holds, which means that all system tracking trajectories can reach the sliding mode surface $$$ s=0 $$$ asymptotically, and the system tracking errors will converge to zero. That also indicates all system state variables will converge to desired values asymptotically.…”

“…According to Barbalat lemma [36], lim t→∞ [𝜅s T s+𝜂||s|| 1 ] = 0 holds, which means that all system tracking trajectories can reach the sliding mode surface s = 0 asymptotically, and the system tracking errors will converge to zero. That also indicates all system state variables will converge to desired values asymptotically.…”

Sliding mode controller based aircraft automatic landing for alternate profiles

“…Furthermore, the history of SMC designed reveals that many aerospace control related problems have been solved apart from automatic landing. More explicitly, spiral, 20 stall, 21 spin entry, 22 spin recovery, 23,24 actuator fault 25,26 and reconfigurable flight control system designed 27 to name a few have been implemented using the SMC. Real-time applications in ref.…”

Vertical thrust-based effective flat-spin recovery of aircraft restricting altitude loss

“…For fully developed flat-spin recovery, researcher proposed an intelligent control, reinforcement learning-based optimal strategy, which showed the recovery with minimum time, 13 but again, the altitude required for recovery had not been mentioned. For altitude required for flat-spin recovery, the investigation was carried out 14 using SMC, and the required minimum altitude margin to avoid the ground collision was shown. This margin was ensured by repeated altitude simulations; however, when low altitude flight is concerned, this investigated margin is not sufficient to save the aircraft.…”