3,382 research outputs found
Discrete Adaptive Second Order Sliding Mode Controller Design with Application to Automotive Control Systems with Model Uncertainties
Sliding mode control (SMC) is a robust and computationally efficient solution
for tracking control problems of highly nonlinear systems with a great deal of
uncertainty. High frequency oscillations due to chattering phenomena and
sensitivity to data sampling imprecisions limit the digital implementation of
conventional first order continuous-time SMC. Higher order discrete SMC is an
effective solution to reduce the chattering during the controller software
implementation, and also overcome imprecisions due to data sampling. In this
paper, a new adaptive second order discrete sliding mode control (DSMC)
formulation is presented to mitigate data sampling imprecisions and
uncertainties within the modeled plant's dynamics. The adaptation mechanism is
derived based on a Lyapunov stability argument which guarantees asymptotic
stability of the closed-loop system. The proposed controller is designed and
tested on a highly nonlinear combustion engine tracking control problem. The
simulation test results show that the second order DSMC can improve the
tracking performance up to 80% compared to a first order DSMC under sampling
and model uncertainties.Comment: 6 pages, 6 figures, 2017 American Control Conferenc
Adaptive Discrete Second Order Sliding Mode Control with Application to Nonlinear Automotive Systems
Sliding mode control (SMC) is a robust and computationally efficient
model-based controller design technique for highly nonlinear systems, in the
presence of model and external uncertainties. However, the implementation of
the conventional continuous-time SMC on digital computers is limited, due to
the imprecisions caused by data sampling and quantization, and the chattering
phenomena, which results in high frequency oscillations. One effective solution
to minimize the effects of data sampling and quantization imprecisions is the
use of higher order sliding modes. To this end, in this paper, a new
formulation of an adaptive second order discrete sliding mode control (DSMC) is
presented for a general class of multi-input multi-output (MIMO) uncertain
nonlinear systems. Based on a Lyapunov stability argument and by invoking the
new Invariance Principle, not only the asymptotic stability of the controller
is guaranteed, but also the adaptation law is derived to remove the
uncertainties within the nonlinear plant dynamics. The proposed adaptive
tracking controller is designed and tested in real-time for a highly nonlinear
control problem in spark ignition combustion engine during transient operating
conditions. The simulation and real-time processor-in-the-loop (PIL) test
results show that the second order single-input single-output (SISO) DSMC can
improve the tracking performances up to 90%, compared to a first order SISO
DSMC under sampling and quantization imprecisions, in the presence of modeling
uncertainties. Moreover, it is observed that by converting the engine SISO
controllers to a MIMO structure, the overall controller performance can be
enhanced by 25%, compared to the SISO second order DSMC, because of the
dynamics coupling consideration within the MIMO DSMC formulation.Comment: 12 pages, 7 figures, 1 tabl
Optimal sliding mode controllers for attitude tracking of spacecraft
This paper studies two optimal sliding mode control laws using integral sliding mode control (ISM) for some spacecraft attitude tracking problems. Integral sliding mode control combining the first order sliding mode and optimal control is applied to quaternion-based spacecraft attitude tracking manoeuvres with external disturbances and an uncertainty inertia matrix. For the optimal control part the state dependent Riccati equation (SDRE) and Control Lyapunov function (CLF) approaches are used to solve the infinite-time nonlinear optimal problem. The second method of Lyapunov is used to show that tracking is achieved globally. An example of multiaxial attitude tracking manoeuvres is presented and simulation results are included to verify the usefulness of these controllers
Integral sliding mode fault tolerant control allocation for a class of affine nonlinear system
This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.This paper develops novel fault tolerant integral sliding mode control allocation schemes for a class of
over-actuated affine nonlinear system. The proposed schemes rely on an existing baseline controller and the
objective is to retain the nominal (fault-free) closed-loop performance in the face of actuator faults/failures
by effectively utilizing actuator redundancy. The online control allocation reroutes the control effort to the
healthy actuators using knowledge of the actuator effectiveness level estimates. One of the proposed schemes
is tested in simulation using a well known high fidelity model of a large civil transport aircraft (B747) from
the literature. Good simulation results show the efficacy of the scheme
An integral sliding-mode parallel control approach for general nonlinear systems via piecewise affine linear models
The fundamental problem of stabilizing a general nonaffine continuous-time
nonlinear system is investigated via piecewise affine linear models (PALMs) in
this article. A novel integral sliding-mode parallel control (ISMPC) approach
is developed, where an uncertain piecewise affine system (PWA) is constructed
to model a nonaffine continuous-time nonlinear system equivalently on a compact
region containing the origin. A piecewise sliding-mode parallel controller is
designed to globally stabilize the PALM and, consequently, to semiglobally
stabilize the original nonlinear system. The proposed scheme enjoys three
favorable features: (i) some restrictions on the system input channel are
eliminated, thus the developed method is more relaxed compared with the
published approaches; (ii) it is convenient to be used to deal with both
matched and unmatched uncertainties of the system; and (iii) the proposed
piecewise parallel controller generates smooth control signals even around the
boundaries between different subspaces, which makes the developed control
strategy more implementable and reliable. Moreover, we provide discussions
about the universality analysis of the developed control strategy for two kinds
of typical nonlinear systems. Simulation results from two numerical examples
further demonstrate the performance of the developed control approach
Active actuator fault-tolerant control of a wind turbine benchmark model
This paper describes the design of an active fault-tolerant control scheme that is applied to the actuator of a
wind turbine benchmark. The methodology is based on adaptive filters obtained via the nonlinear geometric
approach, which allows to obtain interesting decoupling property with respect to uncertainty affecting the
wind turbine system. The controller accommodation scheme exploits the on-line estimate of the actuator
fault signal generated by the adaptive filters. The nonlinearity of the wind turbine model is described by the
mapping to the power conversion ratio from tip-speed ratio and blade pitch angles. This mapping represents
the aerodynamic uncertainty, and usually is not known in analytical form, but in general represented by
approximated two-dimensional maps (i.e. look-up tables). Therefore, this paper suggests a scheme to
estimate this power conversion ratio in an analytical form by means of a two-dimensional polynomial, which
is subsequently used for designing the active fault-tolerant control scheme. The wind turbine power generating
unit of a grid is considered as a benchmark to show the design procedure, including the aspects of
the nonlinear disturbance decoupling method, as well as the viability of the proposed approach. Extensive
simulations of the benchmark process are practical tools for assessing experimentally the features of the
developed actuator fault-tolerant control scheme, in the presence of modelling and measurement errors.
Comparisons with different fault-tolerant schemes serve to highlight the advantages and drawbacks of the
proposed methodology
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