H(infinity) and mu synthesis for full control of helicopter in hover

FEASIBILITY OF SUBSPACE IDENTIFICATION FOR BIPEDS - An Innovative Approach for Kino-Dynamic Systems

“…If a system is hard to model from first principles (as Newton's laws of motion) or there are time varying nonlinearities then direct adaptive control would suite the application. Examples of plants which are difficult to model are arc furnaces (Wilson (1997); Staib and Staib (1992)) and helicopter rotors (Lohar (2000); Tischler et al (1994)). Biped robots on the other hand can be modeled but they exhibit time varying nonlinearities (Wolkotte (2003); Kim et al (2004); Caballero et al 2004).…”

Robust multi-mode flight control design for an unmanned helicopter based on multi-loop structure

“…However it does not provide a systematic way to consider uncertainties, disturbance, input saturation and cross-couplings among channels, [8]. Thereafter, researchers used multivariable techniques for design of stability augmentation and guidance systems for helicopter, such as Eigenstructure Assignment [9], LQG/LQG [10], µ -synthesis [11], H 2 [12], and H ∞ [13][14][15][16]. Among MIMO approaches, H ∞ theory is the most widely used in recent decade as it provides robust stability for systems subject to uncertainty and disturbance.…”

“…Control design for unmanned helicopter has been considered as a challenge in aeronautical field over decades [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. The main difficulties, in designing controllers for UAH, can be generally characterized as underactuated, cross-coupled, large uncertainties, openloop instabilities and highly nonlinear dynamics, [2,3,5].…”

“…In spite of all these challenges, a number of researchers have worked on designing UAHs and wide set of design techniques, from classical control to neuralbased adaptive control, [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17], have been reported. Among early control technique, one-loop-at-a-time control design methods, based on classical single input single output (SISO) techniques with a proportionalplus-integral (PI) configuration are the most widely used [5][6][7][8].…”