236 research outputs found
Rigid Body Attitude Estimation: An Overview and Comparative Study
The attitude estimation of rigid body systems has attracted the attention of many researchers over the years. The development of efficient estimation algorithms that can accurately estimate the orientation of a rigid body is a crucial step towards a reliable implementation of control schemes for underwater and flying vehicles.
The primary focus of this thesis consists in investigating various attitude estimation techniques and their applications.
Two major classes are discussed. The first class consists of the earliest static attitude determination techniques relying solely on a set of body vector measurements of known vectors in the inertial frame. The second class consists of dynamic attitude estimation and filtering techniques, relying on body vector measurements as well other measurements, and using the dynamical equations of the system under consideration.
Various attitude estimation algorithms, including the latest nonlinear attitude observers, are presented and discussed, providing a survey that covers the evolution and structural differences of these estimation methods.
Simulation results have been carried out for a selected number of such attitude estimators. Their performance in the presence of noisy measurements, as well as their advantages and disadvantages are discussed
Local observers on linear Lie groups with linear estimation error dynamics
This paper proposes local exponential observers for systems on linear Lie
groups. We study two different classes of systems. In the first class, the full
state of the system evolves on a linear Lie group and is available for
measurement. In the second class, only part of the system's state evolves on a
linear Lie group and this portion of the state is available for measurement. In
each case, we propose two different observer designs. We show that, depending
on the observer chosen, local exponential stability of one of the two
observation error dynamics, left- or right-invariant error dynamics, is
obtained. For the first class of systems these results are developed by showing
that the estimation error dynamics are differentially equivalent to a stable
linear differential equation on a vector space. For the second class of system,
the estimation error dynamics are almost linear. We illustrate these observer
designs on an attitude estimation problem
Velocity-aided Attitude Estimation for Accelerated Rigid Bodies
Two nonlinear observers for velocity-aided attitude estimation, relying on
gyrometers, accelerometers, magnetometers, and velocity measured in the
body-fixed frame, are proposed. As opposed to state-of-the-art body-fixed
velocity-aided attitude observers endowed with local properties, both observers
are (almost) globally asymptotically stable, with very simple and flexible
tuning. Moreover, the roll and pitch estimates are globally decoupled from
magnetometer measurements
Angular velocity nonlinear observer from single vector measurements
The paper proposes a technique to estimate the angular velocity of a rigid
body from single vector measurements. Compared to the approaches presented in
the literature, it does not use attitude information nor rate gyros as inputs.
Instead, vector measurements are directly filtered through a nonlinear observer
estimating the angular velocity. Convergence is established using a detailed
analysis of a linear-time varying dynamics appearing in the estimation error
equation. This equation stems from the classic Euler equations and measurement
equations. As is proven, the case of free-rotation allows one to relax the
persistence of excitation assumption. Simulation results are provided to
illustrate the method.Comment: 10 pages, 8 figures. arXiv admin note: substantial text overlap with
arXiv:1503.0287
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