Page 26 - ASME DSCC 2015 Program

Technical Program

efficient Lithium-Ion Battery Model predictive control using 1-2 aeroSpace appLIcaTIoNS
differential flatness-Based pseudospectral Methods 1-2-1 WM1 Aerospace Applications 1
Invited session paper. DSCC2015-9765 George Bellows A 1:30pm–3:30pm
Ji liu, Hosam K. fathy, Pennsylvania State University, University Park, PA,
United States, Guang li, Queen Mary, University of London, London, United Session Chair: Beibei Ren, Texas Tech University
Kingdom Session Co-Chair: Hanz Richter, Cleveland State University
This paper proposes an efficient nonlinear model predictive control (NMPC)
Design of an Adaptive Singularity-free Control Moment Gyroscope
framework to solve nonconvex lithium-ion battery trajectory optimization
(ASCMG) Cluster for Spacecraft Attitude Control
problems for battery management systems (BMS). It is challenging to solve
Contributed regular paper. DSCC2015-9818
these problems online due to complexity and nonconvexity. To address
these challenges, we combine four established techniques from the control Sasi Prabhakaran Viswanathan, Amit Sanyal, New Mexico State
literature. First, we represent the single particle model (SPM) using orthog- University, Las Cruces, NM, United States
onal projection techniques. Second, we exploit the differential flatness of Spacecraft attitude control using an Adaptive Singularityfree Control Mo-
Fick’s second law of diffusion to capture all of the dynamics in one electrode ment Gyroscope (ASCMG) cluster design for internal actuation is presented.
using a single scalar trajectory of a “flat output” variable. Third, we optimize A complete dynamics model is derived using the principles of variational
the above flat output trajectories using pseudospectral methods. Fourth, mechanics, relaxing some common assumptions made in prior literature on
we employ the NMPC strategy to solve the battery trajectory optimization control moment gyroscopes. These assumptions include perfect axisymme-
problem online. The proposed NMPC framework is demonstrated by solving try of the rotor and gimbal structures, and perfect alignment of the centers
2 optimal charging problems accounting for physics-based side reaction of mass of the gimbal and the rotor. The resulting dynamics display complex
constraints and is shown to be twice as computationally efficient as pseudo- nonlinear coupling between the internal degrees of freedom associated
spectral online optimization alone. with the CMG and the spacecraft base body’s rotational degrees of free-
Performance Evaluation of An Extended Kalman filter for State dom in the absence of these assumptions. This dynamics model is further
Estimation of A Pseudo-2D Thermal-Electrochemical lithium-Ion generalized to include the effects of multiple CMGs placed in the spacecraft
Battery Model bus, and sufficient conditions for non-singular CMG cluster configurations
Invited session paper. DSCC2015-9836 are obtained. General ideas on control of the angular momentum of the
spacecraft using changes in the momentum variables of a finite number of
Shi Zhao, Adrien M Bizeray, Stephen R Duncan, David A Howey,
University of Oxford, Oxford, County (optional), United Kingdom CMGs, are provided. A control scheme using a finite number of CMGs in the
absence of external torques and when the total angular momentum of the
Performance Evaluation of An Extended Kalman Filter For State Estimation of spacecraft is zero, is presented. The dynamics model of the spacecraft with
A Pseudo-2D Thermal-Electrochemical Lithium-Ion Battery Model a finite number of CMGs is then simplified under the assumption that the
Electrochemical Model-Based Adaptive Estimation of li-Ion Battery rotor is axisymmetric, in which case it is shown that singularities are avoided.
State of Charge As an example, the case of three CMGs with axisymmetric rotors, placed in
Invited session paper. DSCC2015-9918 a tetrahedron configuration inside the spacecraft, is considered. The control
scheme is then numerically implemented using a geometric variational
Nima Lotfi, robert Landers, jie Li, jonghyun park, Missouri University of
Science and Technology, Rolla, MO, United States integrator and the results confirm the singularity-free property and high
control authority of the ASCMG cluster. Moreover, as rotor misalignments are
Electrochemical model-based estimation techniques have attracted addressed in the dynamics model, the ASCMG cluster can adapt to them
increasing attention in the past decade due to their inherent insight about without requiring hardware changes.
the internal battery operating conditions and limits while being able to
monitor important li-ion battery states. The applicability of these methods is,
however, limited due to the implementation complexity of their underlying
models. In order to facilitate online implementation while maintaining the
physical insight, a reduced-order electrochemical model is used in this work.
This model, which is based on the commonly-used single particle model, is
further improved by incorporating the electrolyte-phase potential. Further-
more, an output-injection observer, suitable for online implementation, is
proposed to estimate SOC. The observer convergence is proved analyti-
cally using Lyapunov theory. Although the proposed observer shows great
performance at low C rates, its accuracy deteriorates at high C-rates. To
overcome this issue and achieve accurate SOC estimates for such charge/
discharge rates, an adaptation algorithm is augmented to the observer. The
adaptation algorithm, which can be implemented online, is used to compen-
sate for model uncertainties, especially at higher C rates. Finally, simulation
results based on a full-order electrochemical model are used to validate the
26 observer performance and effectiveness.