Download or read book Robotic Walking in Natural Terrain written by David S. Wettergreen and published by . This book was released on 1995 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: "A substantial portion of the Earth is inaccessible to any sort of wheeled mechanism -- natural obstacles like large rocks, loose soil, deep ravines, and steep slopes conspire to render rolling locomotion ineffective. Hills, mountains, shores, seabeds, as well as the moon and other planets present similar terrain challenges. In many of these natural terrains, legs are well-suited. They can avoid small obstacles by making discrete contacts and passing up undesirable footholds. Legged mechanisms can climb over obstacles and step across ditches, surmounting terrain discontinuities of body-scale while staying level and stable. To achieve their potential, legged robots must coordinate their leg motions to climb over, step across and walk in natural terrain. These coordinated motions, which support and propel the robot, are called gait. This thesis develops a new method of gait planning and control that enables statically-stable walking robots to produce a gait that is robust and productive in natural terrain. Independent task-achieving processes, called gait behaviors, establish a nominal gait, adapt it to the terrain, and react to disturbances like bumps and slips. Gait controlled in this way enabled the robot Dante II to walk autonomously in natural terrain, including the volcanic crater of Mount Spurr. This method extends to other walking robots as demonstrated by a generalized hexapod that performs the variety of gaits seen in six-legged insects, as well as aperiodic free gaits. The ability to change gait patterns on-the-fly with continuous, stable motion is a new development that enables robots to behave more like animals in adapting their gait to terrain. Finally, this thesis describes why walking robots need predictive plans as well as reflexive behaviors to walk effectively in the real world. It presents a method of guiding the behavior of a walking robot by planning distinct attributes of the desired gait. This partitioning of gait planning avoids the complexity of high degree-of-freedom motion planning. The ability to plan and foresee changes in gait improves performance while maintaining robust safety and stability."
Download or read book Walking Machines written by D. J. Todd and published by Springer. This book was released on 2012-03-19 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first chapter of this book traces the history of the development of walking machines from the original ideas of man-amplifiers and military rough-ground transport to today's diverse academic and industrial research and development projects. It concludes with a brief account of research on other unusual methods of locomotion. The heart of the book is the next three chapters on the theory and engineering of legged robots. Chapter 2 presents the basics of land loco motion, going on to consider the energetics of legged movement and the description and classification of gaits. Chapter 3, dealing with the mechanics of legged vehicles, goes into leg number and arrangement, and discusses mechanical design and actuation methods. Chapter 4 deals with analysis and control, describing the aims of control theory and the methods of modelling and control which have been used for both highly dynamic robots and multi-legged machines. Having dealt with the theory of control it is necessary to discuss the computing system on which control is to be implemented. This is done in Chapter 5, which covers architectures, sensing, algorithms and pro gramming languages. Chapter 6 brings together the threads of the theory and engineering discussed in earlier chapters and summarizes the current walking machine research projects. Finally, the applications, both actual and potential, of legged locomotion are described. Introduction Research into legged machines is expanding rapidly. There are several reasons why this is happening at this particular time.
Download or read book Gait Optimization for Multi legged Walking Robots with Application to a Lunar Hexapod written by Daniel Chávez-Clemente and published by Stanford University. This book was released on 2011 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: The interest in using legged robots for a variety of terrestrial and space applications has grown steadily since the 1960s. At the present time, a large fraction of these robots relies on electric motors at the joints to achieve mobility. The load distributions inherent to walking, coupled with design constraints, can cause the motors to operate near their maximum torque capabilities or even reach saturation. This is especially true in applications like space exploration, where critical mass and power constraints limit the size of the actuators. Consequently, these robots can benefit greatly from motion optimization algorithms that guarantee successful walking with maximum margin to saturation. Previous gait optimization techniques have emphasized minimization of power requirements, but have not addressed the problem of saturation directly. This dissertation describes gait optimization techniques specifically designed to enable operation as far as possible from saturation during walking. The benefits include increasing the payload mass, preserving actuation capabilities to react to unforeseen events, preventing damage to hardware due to excessive loading, and reducing the size of the motors. The techniques developed in this work follow the approach of optimizing a reference gait one move at a time. As a result, they are applicable to a large variety of purpose-specific gaits, as well as to the more general problem of single pose optimization for multi-limbed walking and climbing robots. The first part of this work explores a zero-interaction technique that was formulated to increase the margin to saturation through optimal displacements of the robot's body in 3D space. Zero-interaction occurs when the robot applies forces only to sustain its weight, without squeezing the ground. The optimization presented here produces a swaying motion of the body while preserving the original footfall locations. Optimal displacements are found by solving a nonlinear optimization problem using sequential quadratic programming (SQP). Improvements of over 20% in the margin to saturation throughout the gait were achieved with this approach in simulation and experiments. The zero-interaction technique is the safest in the absence of precise knowledge of the contact mechanical properties and friction coefficients. The second part of the dissertation presents a technique that uses the null space of contact forces to achieve greater saturation margins. Interaction forces can significantly contribute to saturation prevention by redirecting the net contact force relative to critical joints. A method to obtain the optimal distribution of forces for a given pose via linear programming (LP) is presented. This can be applied directly to the reference gait, or combined with swaying motion. Improvements of up to 60% were observed in simulation by combining the null space with sway. The zero-interaction technique was implemented and validated on the All Terrain Hex-Limbed Extra-Terrestrial Explorer (ATHLETE), a hexapod robot developed by NASA for the transport of heavy cargo on the surface of the moon. Experiments with ATHLETE were conducted at the Jet Propulsion Laboratory in Pasadena, California, confirming the benefits predicted in simulation. The results of these experiments are also presented and discussed in this dissertation.
Download or read book Control of Walking Robots on Natural Terrain written by Glauco Augusto de Paula Caurin and published by . This book was released on 1994 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bipedal Robotic Walking on Flat Ground Up Slope and Rough Terrain with Human Inspired Hybrid Zero Dynamics written by Shishir Nadubettu Yadukumar and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The thesis shows how to achieve bipedal robotic walking on flat-ground, up-slope and rough terrain by using Human-Inspired control. We begin by considering human walking data and find outputs (or virtual constraints) that, when calculated from the human data, are described by simple functions of time (termed canonical walking functions). Formally, we construct a torque controller, through model inversion, that drives the outputs of the robot to the outputs of the human as represented by the canonical walking function; while these functions fit the human data well, they do not apriori guarantee robotic walking (due to do the physical differences between humans and robots). An optimization problem is presented that determines the best fit of the canonical walking function to the human data, while guaranteeing walking for a specific bipedal robot; in addition, constraints can be added that guarantee physically realizable walking. We consider a physical bipedal robot, AMBER, and considering the special property of the motors used in the robot, i.e., low leakage inductance, we approximate the motor model and use the formal controllers that satisfy the constraints and translate into an efficient voltage-based controller that can be directly implemented on AMBER. The end result is walking on flat-ground and up-slope which is not just human-like, but also amazingly robust. Having obtained walking on specific well defined terrains separately, rough terrain walking is achieved by dynamically changing the extended canonical walking functions (ECWF) that the robot outputs should track at every step. The state of the robot, after every non-stance foot strike, is actively sensed and the new CWF is constructed to ensure Hybrid Zero Dynamics is respected in the next step. Finally, the technique developed is tried on different terrains in simulation and in AMBER showing how the walking gait morphs depending on the terrain. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/148284
Download or read book Real Time Control of Walking written by M.D. Donner and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: I wonder whether Karel Capek imagined in 1923 that by his use of the Czech word for forced labor, rohota, to name the android creations of Mr. Rossum he was naming an important technology of his future. Perhaps it wasn't Capek's work directly, but rather its influence on Lang's movie Metropolis in 1926 that introduced the term to the popular consciousness. In the public mind ever since a robot has been a me chanical humanoid, tireless and somewhat sinister. In the research community the field of robotics has recently reached large size and respectability, but without answering the question, "What is robotics?" or perhaps, "What is a robot?" There is no real consensus for a precise definition of robotics. I suppose that Capekian mechanical men, if one could build them, are robots, but after that there is little agreement. Rather than try to enumerate all of the things that are and are not robots, I will try to characterize the kinds of features that make a system a robot. A candidate definition of a robot is a system intended to achieve mechanical action, with sensory feedback from the world to guide the actions and a sophisticated con trol system connecting the sensing and the actions.
Download or read book Climbing and Walking Robots written by Behnam Miripour-Fard and published by BoD – Books on Demand. This book was released on 2010-03-01 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nowadays robotics is one of the most dynamic fields of scientific researches. The shift of robotics researches from manufacturing to services applications is clear. During the last decades interest in studying climbing and walking robots has been increased. This increasing interest has been in many areas that most important ones of them are: mechanics, electronics, medical engineering, cybernetics, controls, and computers. Today’s climbing and walking robots are a combination of manipulative, perceptive, communicative, and cognitive abilities and they are capable of performing many tasks in industrial and non- industrial environments. Surveillance, planetary exploration, emergence rescue operations, reconnaissance, petrochemical applications, construction, entertainment, personal services, intervention in severe environments, transportation, medical and etc are some applications from a very diverse application fields of climbing and walking robots. By great progress in this area of robotics it is anticipated that next generation climbing and walking robots will enhance lives and will change the way the human works, thinks and makes decisions. This book presents the state of the art achievments, recent developments, applications and future challenges of climbing and walking robots. These are presented in 24 chapters by authors throughtot the world The book serves as a reference especially for the researchers who are interested in mobile robots. It also is useful for industrial engineers and graduate students in advanced study.
Download or read book Efficient Robotic Walking by Learning Gaits and Terrain Properties written by Sandeep Manjanna and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "In this thesis, we investigate the question of how a legged robot can walk efficiently, and take advantage of its ability to alter its gait. This work targets the issue of increasing the efficiency of legged vehicles on different challenging terrains. We decompose the problem into three sub-problems: walking gait problem, physical adaptation problem, and terrain identification and gait adaptation problem. In the walking gait sub-problem, we investigate the effects of gait parameters on the performance of the robot. In particular, we assess the ground speed, power efficiency and terrain sensibility of the robot at varying leg cycle frequencies. In the physical adaptation sub-problem, we investigate the effects of different kinds of legs on the robot's performance. We also look at the influence of leg-compliance on walking behavior. In the terrain identification and gait adaptation sub-problem, we design a gait adaptation algorithm to identify the terrain by initially classifying the proprioceptive information collected over different terrains and then adapt its gait accordingly. Identifying the terrain in real-time helps the robot plan its gait on that terrain and effectively increase the walking efficiency in real-time. We use a cost-based unsupervised learning algorithm to classify the terrain data. In our experiments, we use proprioceptive sensor data collected by running the robot on four different terrains. We also use synthetic data for verifying our algorithm. We conclude with an analysis of the data and validate the performance of our algorithm." --
Download or read book Climbing and Walking Robots and the Support Technologies for Mobile Machines written by Phillippe Bidaud and published by John Wiley & Sons. This book was released on 2002-11-08 with total page 1080 pages. Available in PDF, EPUB and Kindle. Book excerpt: Robotic technology advances for a wide variety of applications Climbing and Walking Robots and the Support Technologies for Mobile Machines explores the increasing interest in real-world robotics and the surge in research and invention it has inspired. Featuring the latest advances from leading robotics labs around the globe, this book presents solutions for perennial challenges in robotics and suggests directions for future research. With applications ranging from personal services and entertainment to emergency rescue and extreme environment intervention, the groundbreaking work presented here provides a glimpse of the future.
Download or read book Advances in Climbing and Walking Robots written by Ming Xie and published by . This book was released on 2007 with total page 818 pages. Available in PDF, EPUB and Kindle. Book excerpt: Robotics is an exciting field in engineering and natural sciences. Robotics has already made a significant contribution to many industries with the widespread use of industrial robots for tasks such as assembly, welding, painting, and handling materials. In parallel, we have witnessed the emergence of special robots which can undertake assistive jobs, such as search and rescue, de-mining, surveillance, exploration, and security functions. Indeed, the interest in mobile machines, such as climbing and walking robots, has broadened the scope of investigation in robotics. This volume covers broad topics related to mobile machines in general, and climbing and walking robots in particular. Papers from the following keynote speakers are included: Heinz Worn (University of Karlsruhe, Germany), Atsuo Takanishi (University of Waseda, Japan), John Billingsley (University of Southern Queensland, Australia), Bryan Bridge (London South Bank University, UK) and Neville Hogan (Massachusetts Institute of Technology, USA).
Download or read book Walking Biological and Technological Aspects written by Friedrich Pfeiffer and published by Springer Science & Business Media. This book was released on 2004-10-20 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book describes the results of research into the living world, which were conducted in such a way as to provide inspiration to engineering design of walking machines. The biological topics are presented in a form that is intelligible to engineers and can be applied in the design of mechanical devices. The text also introduces the design problems that are encountered during prototyping of specific robots. This information provides insight to biologists interested in basic physical properties of locomotion.
Download or read book Energy economical Heuristically Based Control of Compass Gait Walking on Stochastically Varying Terrain written by Christian Michael Hubicki and published by . This book was released on 2011 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: Investigation uses simulation to explore the inherent tradeoffs of controlling high-speed and highly robust walking robots while minimizing energy consumption. Using a novel controller which optimizes robustness, energy economy, and speed of a simulated robot on rough terrain, the user can adjust their priorities between these three outcome measures and systematically generate a performance curve assessing the tradeoffs associated with these metrics.
Download or read book Bipedal Robots written by Christine Chevallereau and published by John Wiley & Sons. This book was released on 2013-03-01 with total page 249 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents various techniques to carry out the gait modeling, the gait patterns synthesis, and the control of biped robots. Some general information on the human walking, a presentation of the current experimental biped robots, and the application of walking bipeds are given. The modeling is based on the decomposition on a walking step into different sub-phases depending on the way each foot stands into contact on the ground. The robot design is dealt with according to the mass repartition and the choice of the actuators. Different ways to generate walking patterns are considered, such as passive walking and gait synthesis performed using optimization technique. Control based on the robot modeling, neural network methods, or intuitive approaches are presented. The unilaterality of contact is dealt with using on-line adaptation of the desired motion.
Download or read book A General Model of Legged Locomotion on Natural Terrain written by David J. Manko and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dynamic modeling is the fundamental building block for mechanism analysis, design, control and performance evaluation. One class of mechanism, legged machines, have multiple closed-chains established through intermittent ground contacts. Further, walking on natural terrain introduces nonlinear system compliance in the forms of foot sinkage and slippage. Closed-chains constrain the possible motions of a mechanism while compliances affect the redistribution of forces throughout the system. A General Model of Legged Locomotion on Natural Terrain develops a dynamic mechanism model that characterizes indeterminate interactions of a closed-chain robot with its environment. The approach is applicable to any closed-chain mechanism with sufficient contact compliance, although legged locomotion on natural terrain is chosen to illustrate the methodology. The modeling and solution procedures are general to all walking machine configurations, including bipeds, quadrupeds, beam-walkers and hopping machines. This work develops a functional model of legged locomotion that incorporates, for the first time, non-conservative foot-soil interactions in a nonlinear dynamic formulation. The model was applied to a prototype walking machine, and simulations generated significant insights into walking machine performance on natural terrain. The simulations are original and essential contributions to the design, evaluation and control of these complex robot systems. While posed in the context of walking machines, the approach has wider applicability to rolling locomotors, cooperating manipulators, multi-fingered hands, and prehensile agents.
Download or read book The Design and Realization of a Sensitive Walking Platform written by Vadim Chernyak and published by . This book was released on 2012 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Legged locomotion provides robots with the capability of adapting to different terrain conditions. General complex terrain traversal methodologies solely rely on proprioception which readily leads to instability under dynamical situations. Biological legged locomotion utilizes somatosensory feedback to sense the real-time interaction of the feet with ground to enhance stability. Nevertheless, limited attention has been given to sensing the feet-terrain interaction in robotics. This project introduces a paradigm shift in robotic walking called sensitive walking realized through the development of a compliant bipedal platform. Sensitive walking extends upon the success of sensitive manipulation which utilizes tactile feedback to localize an object to grasp, determine an appropriate manipulation configuration, and constantly adapts to maintain grasp stability. Based on the same concepts of sensitive manipulation, sensitive walking utilizes podotactile feedback to enhance real-time walking stability by effectively adapting to variations in the terrain. Adapting legged robotic platforms to sensitive walking is not as simple as attaching any tactile sensor to the feet of a robot. The sensors and the limbs need to have specific characteristics that support the implementation of the algorithms and allow the biped to safely come in contact with the terrain and detect the interaction forces. The challenges in handling the synergy of hardware and sensor design, and fabrication in a podotactile-based sensitive walking robot are addressed. The bipedal platform provides contact compliance through 12 series elastic actuators and contains 190 highly flexible tactile sensors capable of sensing forces at any incident angle. Sensitive walking algorithms are provided to handle multi-legged locomotion challenges including stairs and irregular terrain.
Download or read book Gait Planning and Transitions of Walking Robots on Smooth and Rough Terrains written by Tina Y. Ye and published by . This book was released on 2003 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Robust Bipedal Locomotion on Unknown Terrain written by Hongkai Dai (S.M.) and published by . This book was released on 2012 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: A wide variety of bipedal robots have been constructed with the goal of achieving natural and efficient walking in outdoor environments. Unfortunately, there is still a lack of general schemes enabling the robots to reject terrain disturbances. In this thesis, two approaches are presented to enhance the performance of bipedal robots walking on modest terrain. The first approach searches for a walking gait that is intrinsically easily stabilized. The second approach constructs a robust controller to steer the robot towards the designated walking gait. Mathematically, the problem is modeled as rejecting the uncertainty in the guard function of a hybrid nonlinear system. Two metrics are proposed to quantify the robustness of such systems. The first metric concerns the 'average performance' of a robot walking over a stochastic terrain. The expected LQR cost-to-go for the post-impact states is chosen to measure the difficulty of steering those perturbed states back to the desired trajectory. A nonlinear programming problem is formulated to search for a trajectory which takes the least effort to stabilize. The second metric deals with the 'worst case performance', and defines the L2 gain for the linearization of the hybrid nonlinear system around a nominal periodic trajectory. In order to reduce the L2 gain, an iterative optimization scheme is presented. In each iteration, the algorithm solves a semidefinite programming problem to find the quadratic storage function and integrates a periodic differential Riccati equation to compute the linear controller. The simulation results demonstrate that both metrics are correlated to the actual number of steps the robot can traverse on the rough terrain without falling down. By optimizing these two metrics, the robot can walk a much longer distance over the unknown landscape.
