Dynamic Optimization of a Rimless Wheel with an Actuated Pendulum

As the demand for mobile robots that work alongside humans increases, the amount of energy that these co-robots consume will become a critical limiting factor in their deployment. This need is clearly captured in one of the fifteen main goals of the 2009 Roadmap for US Robotics which is to create a robot that can walk with half the energy consumption of a human being. At this point, the most energy-efficient walking robot is about as energy efficient as a human. Energy efficient bipedal motion is an active area of research. It has been proven that it is theoretically possible to design a robot with intermittent support, one of the most fundamental attributes of legged locomotion, to have a zero-energy cost collisionless gait. Optimal control has been used by a number of researchers to study the generation of periodic gaits for walking robots. However little research exists demonstrating walkers with energy efficient collisionless motion. The research that does exist demonstrates that a significant amount of the energy lost to the system when walking is from losses due to step collisions. In this work energy efficient locomotion of a prototype actuated rimless wheel on level ground is explored using numerical optimal control. The actuated rimless wheel has an internal pendulum driven by a DC motor. The locomotion problem is posed as an optimal control problem. Different cost functions and initial configurations are investigated and the corresponding gait trajectories analyzed and assessed based on their use of energy and the potential for collisionless motion

Computational dynamics: theory and applications of multibody systems

International audienceMultibody system dynamics is an essential part of computational dynamics a topic more generally dealing with kinematics and dynamics of rigid and flexible systems, finite elements methods, and numerical methods for synthesis, optimization and control including nonlinear dynamics approaches. The theoretical background of multibody dynamics is presented, the efficiency of recursive algorithms is shown, methods for dynamical analysis are summarized, and applications to vehicle dynamics and biomechanics are reported. In particular, the wear of railway wheels of high-speed trains and the metabolical cost of human locomotion is analyzed using multibody system methods

A Bioinspired Dynamical Vertical Climbing Robot

This paper describes the inspiration, design, analysis, implementation of and experimentation with the first dynamical vertical climbing robot. Biologists have proposed a pendulous climbing model that abstracts remarkable similarities in dynamic wall scaling behavior exhibited by radically different animal species. We study numerically a version of that pendulous climbing template dynamically re-scaled for applicability to utilitarian payloads with conventional electronics and actuation. This simulation study reveals that the incorporation of passive compliance can compensate for an artifact’s poorer power density and scale disadvantages relative to biology. However the introduction of additional dynamical elements raises new concerns about stability regarding both the power stroke and limb coordination that we allay via mathematical analysis of further simplified models. Combining these numerical and analytical insights into a series of design prototypes, we document the correspondence of the various models to the variously scaled platforms and report that our approximately two kilogram platform climbs dynamically at vertical speeds up to 1.5 bodylengths per second. In particular, the final 2.6 kg final prototype climbs at an average steady state speed of 0.66 m/s against gravity on a carpeted vertical wall, in rough agreement with our various models’ predictions

Convergence of Bayesian Histogram Filters for Location Estimation

We prove convergence of an approximate Bayesian estimator for the (scalar) location estimation problem by recourse to a histogram approximant. We exploit its tractability to present a simple strategy for managing the tradeoff between accuracy and complexity through the cardinality of the underlying partition. Our theoretical results provide explicit (conservative) sufficient conditions under which convergence is guaranteed. Numerical simulations reveal certain extreme cases in which the conditions may be tight, and suggest that this procedure has performance and computational efficiency favorably comparable to particle filters, while affording the aforementioned analytical benefits. We posit that more sophisticated algorithms can make such piecewise-constant representations similarly feasible for very high-dimensional problems. For more information: Kod*La

Dynamics of Ocean Buoys and Athlete Motion for Energy Harvesting

<p>Small scale energy harvesting has become a prevalent area of study over the last decade. These harvesters are used in a wide range of applications, including the powering of remote sensors for structural health in buildings or bridges, tsunami, submarine and wildlife detection in the ocean, as well as general motion analysis of systems. Though many designs have been created to harvest energy for these purposes, the nonlinear dynamics of both the harvester and, when applicable, its housing (i.e. buoy casing) are widely ignored. Because of this, a significant amount of available power is lost through the limitations of linear designs.</p><p>The first part of this dissertation gives an overview of commonly used linear energy harvesting designs and gives a brief explanation of the limitations of a linear design. Both a simple inertial and linearized magnet-coil model are analytically and numerically studied. This sets the stage for improvement of energy harvesters to operate at a wider range of frequencies by including the inherent nonlinearities of the harvester and/or its environment.</p><p>In the second part, the nonlinear dynamics of ocean buoys of standard, fundamental shapes (spherical and cylindrical) due to wave loading is studied. Experimental, as well as numerical and analytical analysis is performed on these designs. Also given is a description of common wave-loading devices that can be used in a laboratory setting (wavemakers), as well as for the specific device used to obtain experimental data. Additionally, a simple dynamical system is excited by the buoy motion, which is used to calculate the power available if the system was used as an energy harvester.</p><p>The last part of this dissertation looks at the nonlinear dynamics of human motion, with a focus on running events. Analysis is performed on running subjects in order to determine the amount of energy available, as well the frequencies where the most energy is available. This information is then used to recreate the motion numerically, which makes it possible to design a simple energy harvester that operates efficiently in such an environment. This harvester is used to power a timing mechanism that gives frequent and useful information about the athlete's position and speed.</p>Dissertatio

Proceedings of the ECCOMAS Thematic Conference on Multibody Dynamics 2015

This volume contains the full papers accepted for presentation at the ECCOMAS Thematic Conference on Multibody Dynamics 2015 held in the Barcelona School of Industrial Engineering, Universitat Politècnica de Catalunya, on June 29 - July 2, 2015. The ECCOMAS Thematic Conference on Multibody Dynamics is an international meeting held once every two years in a European country. Continuing the very successful series of past conferences that have been organized in Lisbon (2003), Madrid (2005), Milan (2007), Warsaw (2009), Brussels (2011) and Zagreb (2013); this edition will once again serve as a meeting point for the international researchers, scientists and experts from academia, research laboratories and industry working in the area of multibody dynamics. Applications are related to many fields of contemporary engineering, such as vehicle and railway systems, aeronautical and space vehicles, robotic manipulators, mechatronic and autonomous systems, smart structures, biomechanical systems and nanotechnologies. The topics of the conference include, but are not restricted to: ● Formulations and Numerical Methods ● Efficient Methods and Real-Time Applications ● Flexible Multibody Dynamics ● Contact Dynamics and Constraints ● Multiphysics and Coupled Problems ● Control and Optimization ● Software Development and Computer Technology ● Aerospace and Maritime Applications ● Biomechanics ● Railroad Vehicle Dynamics ● Road Vehicle Dynamics ● Robotics ● Benchmark ProblemsPostprint (published version

Vibration, Control and Stability of Dynamical Systems

From Preface: This is the fourteenth time when the conference “Dynamical Systems: Theory and Applications” gathers a numerous group of outstanding scientists and engineers, who deal with widely understood problems of theoretical and applied dynamics. Organization of the conference would not have been possible without a great effort of the staff of the Department of Automation, Biomechanics and Mechatronics. The patronage over the conference has been taken by the Committee of Mechanics of the Polish Academy of Sciences and Ministry of Science and Higher Education of Poland. It is a great pleasure that our invitation has been accepted by recording in the history of our conference number of people, including good colleagues and friends as well as a large group of researchers and scientists, who decided to participate in the conference for the first time. With proud and satisfaction we welcomed over 180 persons from 31 countries all over the world. They decided to share the results of their research and many years experiences in a discipline of dynamical systems by submitting many very interesting papers. This year, the DSTA Conference Proceedings were split into three volumes entitled “Dynamical Systems” with respective subtitles: Vibration, Control and Stability of Dynamical Systems; Mathematical and Numerical Aspects of Dynamical System Analysis and Engineering Dynamics and Life Sciences. Additionally, there will be also published two volumes of Springer Proceedings in Mathematics and Statistics entitled “Dynamical Systems in Theoretical Perspective” and “Dynamical Systems in Applications”

Multibody dynamics 2015

This volume contains the full papers accepted for presentation at the ECCOMAS Thematic Conference on Multibody Dynamics 2015 held in the Barcelona School of Industrial Engineering, Universitat Politècnica de Catalunya, on June 29 - July 2, 2015. The ECCOMAS Thematic Conference on Multibody Dynamics is an international meeting held once every two years in a European country. Continuing the very successful series of past conferences that have been organized in Lisbon (2003), Madrid (2005), Milan (2007), Warsaw (2009), Brussels (2011) and Zagreb (2013); this edition will once again serve as a meeting point for the international researchers, scientists and experts from academia, research laboratories and industry working in the area of multibody dynamics. Applications are related to many fields of contemporary engineering, such as vehicle and railway systems, aeronautical and space vehicles, robotic manipulators, mechatronic and autonomous systems, smart structures, biomechanical systems and nanotechnologies. The topics of the conference include, but are not restricted to: Formulations and Numerical Methods, Efficient Methods and Real-Time Applications, Flexible Multibody Dynamics, Contact Dynamics and Constraints, Multiphysics and Coupled Problems, Control and Optimization, Software Development and Computer Technology, Aerospace and Maritime Applications, Biomechanics, Railroad Vehicle Dynamics, Road Vehicle Dynamics, Robotics, Benchmark Problems. The conference is organized by the Department of Mechanical Engineering of the Universitat Politècnica de Catalunya (UPC) in Barcelona. The organizers would like to thank the authors for submitting their contributions, the keynote lecturers for accepting the invitation and for the quality of their talks, the awards and scientific committees for their support to the organization of the conference, and finally the topic organizers for reviewing all extended abstracts and selecting the awards nominees.Postprint (published version

Dynamical systems : mechatronics and life sciences

Proceedings of the 13th Conference „Dynamical Systems - Theory and Applications" summarize 164 and the Springer Proceedings summarize 60 best papers of university teachers and students, researchers and engineers from whole the world. The papers were chosen by the International Scientific Committee from 315 papers submitted to the conference. The reader thus obtains an overview of the recent developments of dynamical systems and can study the most progressive tendencies in this field of science