  This paper presents a new kind of vectorial backstepping sliding mode control
(BSMC) for the positioning and trajectory tracking of an autonomous robotic
airship. Also, a unified framework basis for the design/analysis of vectorial
BSMC, as well as sliding mode control (SMC) and backstepping control (BS) for a
system in lower triangular block form is derived. The design framework makes it
easier the theoretical-based comparative analysis of performances/robustness
between the three nonlinear control approaches. Simulation results for the
positioning and tracking of the autonomous airship illustrate the proposal.
