16 research outputs found
Chaotification of Impulsive Systems by Perturbations
In this paper, we present a new method for chaos generation in nonautonomous impulsive systems. We prove the presence of chaos in the sense of Li-Yorke by implementing chaotic perturbations. An impulsive Duffing oscillator is used to show the effectiveness of our technique, and simulations that support the theoretical results are depicted. Moreover, a procedure to stabilize the unstable periodic solutions is proposed
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Recent advances in evolutionary and bio-inspired adaptive robotics: exploiting embodied dynamics
This paper explores current developments in evolutionary and bio-inspired approaches to autonomous robotics, concentrating on research from our group at the University of Sussex. These developments are discussed in the context of advances in the wider fields of adaptive and evolutionary approaches to AI and robotics, focusing on the exploitation of embodied dynamics to create behaviour. Four case studies highlight various aspects of such exploitation. The first exploits the dynamical properties of a physical electronic substrate, demonstrating for the first time how component-level analog electronic circuits can be evolved directly in hardware to act as robot controllers. The second develops novel, effective and highly parsimonious navigation methods inspired by the way insects exploit the embodied dynamics of innate behaviours. Combining biological experiments with robotic modeling, it is shown how rapid route learning can be achieved with the aid of navigation-specific visual information that is provided and exploited by the innate behaviours. The third study focuses on the exploitation of neuromechanical chaos in the generation of robust motor behaviours. It is demonstrated how chaotic dynamics can be exploited to power a goal-driven search for desired motor behaviours in embodied systems using a particular control architecture based around neural oscillators. The dynamics are shown to be chaotic at all levels in the system, from the neural to the embodied mechanical. The final study explores the exploitation of the dynamics of brain-body-environment interactions for efficient, agile flapping winged flight. It is shown how a multi-objective evolutionary algorithm can be used to evolved dynamical neural controllers for a simulated flapping wing robot with feathered wings. Results demonstrate robust, stable, agile flight is achieved in the face of random wind gusts by exploiting complex asymmetric dynamics partly enabled by continually changing wing and tail morphologies
Controlling nonlinear dynamical systems into arbitrary states using machine learning
Controlling nonlinear dynamical systems is a central task in many different areas of science and
engineering. Chaotic systems can be stabilized (or chaotified) with small perturbations, yet existing
approaches either require knowledge about the underlying system equations or large data sets as they
rely on phase space methods. In this work we propose a novel and fully data driven scheme relying on
machine learning (ML), which generalizes control techniques of chaotic systems without requiring a
mathematical model for its dynamics. Exploiting recently developed ML-based prediction capabilities,
we demonstrate that nonlinear systems can be forced to stay in arbitrary dynamical target states
coming from any initial state. We outline and validate our approach using the examples of the Lorenz
and the Rössler system and show how these systems can very accurately be brought not only to
periodic, but even to intermittent and different chaotic behavior. Having this highly flexible control
scheme with little demands on the amount of required data on hand, we briefly discuss possible
applications ranging from engineering to medicine