Robust control of unmanned helicopters with high-order mismatched disturbances via disturbance-compensation-gain construction approach

In this paper, a novel robust control strategy based on disturbance-compensationgain
(DCG) construction approach is proposed for small-scale unmanned helicopters
in the presence of high-order mismatched disturbances. The overall
control structure consists of two hierarchical layers. The inner-loop controller
is to guarantee the stability of the unmanned helicopters subject to high-order
mismatched disturbances. With the estimation of the disturbances and their
successive derivatives via finite-time disturbance observer (FTDO), by properly
designing some disturbance compensation gains, a novel robust controller is
developed to remove the high-order mismatched disturbances from the output
channels. The outer-loop controller is to produce flight commands for innerloop
system, as well as to track the reference trajectory, which is carried out
with the dynamic inversion technique. The simulation results demonstrate that
the unmanned helicopters are capable to perform flight missions autonomously
with the proposed control strategy.