In this paper, an observer-based adaptive hybridattitude controller is presented that overcomes the topologicalobstructions associated with the global attitude stabilization.This hybrid controller consists of two major parts: anadaptive trimodal hybrid controller to eliminateunwindingphenomenon, and a centrally synergistic potential function. Inthe adaptive trimodal hybrid controller, the first logic variableselects which quaternion representation of the desired attitudeshould be tracked. Furthermore, an adaptive technique isintroduced to collaborate with the second logic variable toadapt the hysteresis width. The third logic variable controlsthe mismatch between the auxiliary dynamical system and theactual attitude. Moreover, an auxiliary dynamical system anda nonlinear angular velocity observer are presented whoseoutputs are utilized in the proposed feedback control law toattain the necessary damping. Furthermore, a new centrallysynergistic potential function is presented to cooperate withthe trimodal hybrid controller to overcome the topologicalobstruction associated with the vector bundle structure. Therobust global asymptotic stability of the consequent closed-loop system is guaranteed through a Lyapunov analysis. Acomparative analysis in simulations illustrates the effectivenessand superiority of the proposed control scheme.

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