H. Siraramirez et al., DYNAMICAL SLIDING MODE CONTROL APPROACH FOR VERTICAL FLIGHT REGULATION IN HELICOPTERS, IEE proceedings. Control theory and applications, 141(1), 1994, pp. 19-24
A dynamical multivariable discontinuous feedback control strategy of t
he sliding mode type is proposed for the altitude stabilisation of a n
onlinear helicopter model in vertical flight. While retaining the basi
c robustness features associated with sliding mode control policies, t
he proposed approach also results in smoothed out (i.e. nonchattering)
input trajectories and controlled state variable responses.