Spelling suggestions: "subject:"[een] LYAPUNOV STABILITY"" "subject:"[enn] LYAPUNOV STABILITY""
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The control of flexible robotsShifman, Jeffrey Joseph January 1991 (has links)
No description available.
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Lyapunov spectrum and control setsGrünvogel, Stefan Michael. January 2000 (has links)
Thesis (doctoral)--Universität Augsburg, 2000. / Includes bibliographical references (p. 177-179) and index.
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Stable bilateral teleoperation with time-varying delaysYang, Yuan 12 July 2017 (has links)
A teleoperation system is a master-slave robotic system in which the master and slave robots are at different geographical locations and synchronize their motions through the communication channel, with the goal of enabling the human operator to interact with a remote environment. The two primary objectives of bilateral teleoperation systems, position tracking and force feedback, are necessary for providing the user with high fidelity telepresence. However, time delays in communication channels impede the realization of the two objectives and even destabilize the system. To guarantee stability and improve performance, several damping injection-based controllers have been developed in this thesis for two channel and four channel teleoperation systems. For two channel teleoperation, an adaptive bounded state feedback controller has firstly been proposed to address teleoperation with time-varying delays, model uncertainties and bounded actuations. Next, a simplified and augmented globally exponentially convergent velocity observer has been designed and incorporated in the conventional P+d control to obtain stable bilateral teleoperation without using velocity measurements. Then, the more challenging bounded output feedback control problem has been solved by combining the bounded state feedback control and output feedback control two techniques with more conservative control gains. In four channel teleoperation, a hybrid damping and stiffness adjustment strategy has been introduced to tightly constrain the master and slave robots and achieve robust stability. Further, the nonsingular version is developed to conquer the singularity problem in the hybrid strategy, which has been proved to avoid unexpected torque spikes due to the singularity problem at zero velocities. Besides, this thesis has also provided a reduced-order controller to guarantee position coordination for arbitrarily large position errors and maintain the tight coupling between the master and slave sites. After concluding all the research results, future study directions are pointed out at the end of this thesis. / Graduate
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An investigation of techniques for nonlinear state observationMcBride, Dean Christian Tait January 2016 (has links)
A dissertation submitted to the Faculty of Engineering and the Built Environment,
University of the Witwatersrand, in fulfilment of the requirements for the degree of
Master of Science in Engineering.
Johannesburg, 2016 / An investigation and analysis of a collection of different techniques, for estimating the states of
nonlinear systems, was undertaken. It was found that most of the existing literature on the topic
could be organized into several groups of nonlinear observer design techniques, of which each
group follows a specific concept and slight variations thereof.
From out of this investigation it was discovered that a variation of the adaptive observer could be
successfully applied to numerous nonlinear systems, given only limited output information. This
particular technique formed the foundation on which a design procedure was developed in order to
asymptotically estimate the states of nonlinear systems of a certain form, using only partial state
information available. Lyapunov stability theory was used to prove the validity of this technique,
given that certain conditions and assumptions are satisfied. A heuristic procedure was then
developed to get a linearized model of the error transient behaviour that could form the upper
bounds of the transient times of the observer.
The technique above, characterized by a design algorithm, was then applied to three well-known
nonlinear systems; namely the Lorenz attractor, the Rössler attractor, and the Van Der Pol
oscillator. The results, illustrated through numerical simulation, clearly indicate that the technique
developed is successful, provided all assumptions and conditions are satisfied. / MT2017
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Stability Analysis of Uncertain Nonlinear Systems with High-Gain ObserversLiou, Fa-jiun 10 February 2010 (has links)
Based on the Lyapunov stability theorem, a modified stability analysis as well as a modified observer is proposed in this thesis for a class of uncertain nonlinear systems with an existent high gain observer. By assuming that the first two state variables are indirectly measurable, reanalyzing the stability of the error dynamics is presented first. The advantage of this modified analytic method is that the upper bound of the disturbance distribution functions is not required to be known in advance, and the asymptotic stability is still guaranteed. Next, based on this existent observer, a slightly modified observer is presented for systems with disturbances whose upper bound is unknown. An adaptive mechanism is embedded in the proposed observer, so that the upper bound of perturbations is not required to be known beforehand. The resultant dynamics of estimation errors can be driven into the sliding surface in a finite time, and guarantee asymptotic stability. A numerical example and a practical example are given to demonstrate the feasibility of the proposed observer.
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Design of Nonlinear Controllers for Systems with Mismatched PerturbationsChang, Yaote 18 January 2007 (has links)
In this dissertation, four nonlinear controllers are proposed for different class
of multi-input multi-output (MIMO) systems with matched and mismatched perturbations.
All the plants to be controlled contains input uncertainty. The technique
of the adaptive sliding mode control (ASMC) scheme is first introduced in
order to solve the regulation or tracking problems. By applying adaptive techniques
to the design of a novel sliding surface as well as to the design of sliding
mode controller, one can not only enable the fulfillment of reaching mode in fi-
nite time, but also suppress the mismatched perturbations when system is in the
sliding mode. Secondly, the design methodology of block backstepping is proposed
to solve the regulation problem in chapter 5. Some adaptive mechanisms
are employed in the virtual input controller, so that the mismatched perturbations
can be tackled and the proposed robust controller can guarantee stability
of the controlled systems. All these control schemes are designed by means of
Lyapunov stability theorem. Each robust controller contains two parts. The first
part is for eliminating measurable feedback signals of the plant, and the second
part is an adaptive control mechanism, which is capable of adapting some unknown
constants embedded in the least upper bounds of perturbations, so that the
knowledge of the least upper bounds of matched and mismatched perturbations
is not required and can achieve asymptotic stability. Several numerical examples
and industrial applications are demonstrated for showing the feasibility of the
proposed control schemes.
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Dynamical Adaptive Backstepping-Sliding Mode Control of Penumatic ActuatorHe, Liang 23 September 2010 (has links)
This thesis documents the development of a novel nonlinear controller for servo pneumatic actuators that give good reference tracking at low speed motion, where friction has strong effect to the system behaviors. The design of the nonlinear controller presented in this thesis is based on the formalism of Lyapunov stability theory. The controller is constructed through a dynamical adaptive backstepping-sliding mode control algorithm. The conventional Lyapunov-based control algorithm is often limited by the order of the dynamical system; however, the backstepping design concept allows the control algorithm to be extended to higher order dynamical systems. In addition, the friction is estimated on-line via the Lyapunov-based adaptive laws embedded in the controller; meanwhile, the sliding mode control provides high robustness to the system parameter uncertainties. The simulation results clearly demonstrating the improved system performance (i.e., fast response and the reduced tracking error) are presented. Finally, the integration of the controller with a Lyapunov-based pressure observer reduces the state feedback of the servo pneumatic actuator model to only the piston displacement.
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Dynamical Adaptive Backstepping-Sliding Mode Control of Penumatic ActuatorHe, Liang 23 September 2010 (has links)
This thesis documents the development of a novel nonlinear controller for servo pneumatic actuators that give good reference tracking at low speed motion, where friction has strong effect to the system behaviors. The design of the nonlinear controller presented in this thesis is based on the formalism of Lyapunov stability theory. The controller is constructed through a dynamical adaptive backstepping-sliding mode control algorithm. The conventional Lyapunov-based control algorithm is often limited by the order of the dynamical system; however, the backstepping design concept allows the control algorithm to be extended to higher order dynamical systems. In addition, the friction is estimated on-line via the Lyapunov-based adaptive laws embedded in the controller; meanwhile, the sliding mode control provides high robustness to the system parameter uncertainties. The simulation results clearly demonstrating the improved system performance (i.e., fast response and the reduced tracking error) are presented. Finally, the integration of the controller with a Lyapunov-based pressure observer reduces the state feedback of the servo pneumatic actuator model to only the piston displacement.
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Nonlinear control of nonholonomic mobile robot formationsDierks, Travis, January 2007 (has links) (PDF)
Thesis (M.S.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed November 28, 2007) Includes bibliographical references.
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Stability monitoring and analysis of online learning neural networksYerramalla, Sampath. January 1900 (has links)
Thesis (Ph. D.)--West Virginia University, 2005. / Title from document title page. Document formatted into pages; contains xiii, 187 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 165-172).
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