281 research outputs found
Robust Adaptive Learning-based Path Tracking Control of Autonomous Vehicles under Uncertain Driving Environments
This paper investigates the path tracking control
problem of autonomous vehicles subject to modelling uncertainties and external disturbances. The problem is approached
by employing a 2-degree of freedom vehicle model, which is
reformulated into a newly defined parametric form with the
system uncertainties being lumped into an unknown parametric
vector. On top of the parametric system representation, a novel
robust adaptive learning control (RALC) approach is then
developed, which estimates the system uncertainties through
iterative learning while treating the external disturbances by
adopting a robust term. It is shown that the proposed approach
is able to improve the lateral tracking performance gradually
through learning from previous control experiences, despite only
partial knowledge of the vehicle dynamics being available. It is
noteworthy that a novel technique targeting at the non-square
input distribution matrix is employed so as to deal with the
under-actuation property of the vehicle dynamics, which extends
the adaptive learning control theory from square systems to
non-square systems. Moreover, the convergence properties of
the RALC algorithm are analysed under the framework of
Lyapunov-like theory by virtue of the composite energy function
and the λ-norm. The effectiveness of the proposed control
scheme is verified by representative simulation examples and
comparisons with existing methods
Stability profiling of anti-malarial drug piperaquine phosphate and impurities by HPLC-UV, TOF-MS, ESI-MS and NMR
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