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 Gait Optimization for Multi legged Walking Robots with Application to a Lunar Hexapod written by Daniel Chavez Clemente and published by . This book was released on 2011 with total page 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 Hybrid Metaheuristics written by Maria J. Blesa and published by Springer. This book was released on 2016-06-01 with total page 235 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book constitutes the refereed proceedings of the 10th International Workshop on Hybrid Metaheuristics, HM 2016, held in Plymouth, UK, in June 2016. The 15 revised full papers presented were carefully reviewed and selected from 43 submissions. The selected papers are of interest for all the researchers working on integrating metaheuristics with other areas for solving both optimization and constraint satisfaction problems. They represent as well a sample of current research demonstrating how metaheuristics can be integrated with integer linear programming and other operational research techniques for tackling difficult and relevant problems.
Download or read book An Optimization Strategy for Hexapod Gait Transition written by Naga Harika Darbha and published by . This book was released on 2017 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: Legged robots often need to move through different terrains as they function. This requires a change of gaits by the robot in order to move with better efficiency. There has been a lot of research done to find out which gait works better for a given terrain so that the robot can change its gait accordingly. A reliable analysis of when exactly should the transition take place in a walking robot is important, so that there can be an assurance of stability in the locomotion of the robot during the transition between different gaits. This work presents analysis performed on a hexapod robot that can walk in three different gaits: Tripod gait, Ripple gait, and Wave gait, all on a flat terrain. The goal is to optimize the transition of the robot between these gaits by analyzing its stability during motion as the transition is initiated at different times during the stride, called the phase here. A reliable phase at which each transition can be implemented is analyzed with the help of a calculated cost of transition, which is based on the roll and pitch of the robot, and the general body stability margin, which relies upon computation of the support polygon. The roll and pitch of the robot are obtained from simulation of the walking robot as it transitions between gaits, while the stability margin during walking is computed in MATLAB. These values are then combined to determine the cost of transition as the function of the phase at transition. Ultimately, this can be used in real-time walking to determine when transitions should be initiated.
Download or read book Handbook of Research on Advancements in Robotics and Mechatronics written by Habib, Maki K. and published by IGI Global. This book was released on 2014-12-31 with total page 1123 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of mechatronics integrates modern engineering science and technologies with new ways of thinking, enhancing the design of products and manufacturing processes. This synergy enables the creation and evolution of new intelligent human-oriented machines. The Handbook of Research on Advancements in Robotics and Mechatronics presents new findings, practices, technological innovations, and theoretical perspectives on the the latest advancements in the field of mechanical engineering. This book is of great use to engineers and scientists, students, researchers, and practitioners looking to develop autonomous and smart products and systems for meeting todays challenges.
Download or read book Motion and Operation Planning of Robotic Systems written by Giuseppe Carbone and published by Springer. This book was released on 2015-03-12 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses the broad multi-disciplinary topic of robotics, and presents the basic techniques for motion and operation planning in robotics systems. Gathering contributions from experts in diverse and wide ranging fields, it offers an overview of the most recent and cutting-edge practical applications of these methodologies. It covers both theoretical and practical approaches, and elucidates the transition from theory to implementation. An extensive analysis is provided, including humanoids, manipulators, aerial robots and ground mobile robots. ‘Motion and Operation Planning of Robotic Systems’ addresses the following topics: *The theoretical background of robotics. *Application of motion planning techniques to manipulators, such as serial and parallel manipulators. *Mobile robots planning, including robotic applications related to aerial robots, large scale robots and traditional wheeled robots. *Motion planning for humanoid robots. An invaluable reference text for graduate students and researchers in robotics, this book is also intended for researchers studying robotics control design, user interfaces, modelling, simulation, sensors, humanoid robotics.
Download or read book Biomechanics and Robotics written by Marko B. Popovic and published by CRC Press. This book was released on 2013-12-21 with total page 337 pages. Available in PDF, EPUB and Kindle. Book excerpt: The science and technology of biomechanics and robotics promise to be some of the most influential research directions of the twenty-first century. Biomechanics and Robotics goes beyond the individual areas of biomechanics, robotics, biomedical engineering, biomechatronics, and biologically inspired robotics to provide the first unified textbook on
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 Analytical Workspace Kinematics and Foot Force Based Stability of Hexapod Walking Robots written by Mohammad Mahdi Agheli Hajiabadi and published by . This book was released on 2013 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Many environments are inaccessible or hazardous for humans. Remaining debris after earthquake and fire, ship hulls, bridge installations, and oil rigs are some examples. For these environments, major effort is being placed into replacing humans with robots for manipulation purposes such as search and rescue, inspection, repair, and maintenance. Mobility, manipulability, and stability are the basic needs for a robot to traverse, maneuver, and manipulate in such irregular and highly obstructed terrain. Hexapod walking robots are as a salient solution because of their extra degrees of mobility, compared to mobile wheeled robots. However, it is essential for any multi-legged walking robot to maintain its stability over the terrain or under external stimuli. For manipulation purposes, the robot must also have a sufficient workspace to satisfy the required manipulability. Therefore, analysis of both workspace and stability becomes very important. An accurate and concise inverse kinematic solution for multi-legged robots is developed and validated. The closed-form solution of lateral and spatial reachable workspace of axially symmetric hexapod walking robots are derived and validated through simulation which aid in the design and optimization of the robot parameters and workspace. To control the stability of the robot, a novel stability margin based on the normal contact forces of the robot is developed and then modified to account for the geometrical and physical attributes of the robot. The margin and its modified version are validated by comparison with a widely known stability criterion through simulated and physical experiments. A control scheme is developed to integrate the workspace and stability of multi-legged walking robots resulting in a bio-inspired reactive control strategy which is validated experimentally.
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 Gait Development for Use in Dynamic Gait Optimization of Qudrupedrobot Walking written by Mark Will and published by . This book was released on 2000 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ability of walking robots to operate in areas that are inaccessible to wheeled robots has lead to significant research in the field of gait development and optimization for these robots. In this particular study, a catalog of gaits for use in a dynamic gait optimization system to optimize the walking speed of the quadruped Arturo robot on flat terrain is developed. This catalog of robot gaits was developed using a genetic algorithm formulation; various combinations of the selection, mutation, and crossover operators were analyzed. The Arturo robot was modified so that physical verification of the developed gaits could be carried out. The performance of several gaits was analyzed to determine both robot performance and suitability of the gait for use in a dynamic gait optimization system. The feasibility of using solely the position feedback from the joints for surface determination was examined. Piezoelectric crystals (Leybold Inficon 6 Mhz oscillators) were also examined for this application.
Download or read book Multi body Dynamic Modeling of Multi legged Robots written by Abhijit Mahapatra and published by Springer Nature. This book was released on 2020-02-27 with total page 203 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the development of an integrated approach for generating the path and gait of realistic hexapod robotic systems. It discusses in detail locomation with straight-ahead, crab and turning motion capabilities in varying terrains, like sloping surfaces, staircases, and various user-defined rough terrains. It also presents computer simulations and validation using Virtual Prototyping (VP) tools and real-world experiments. The book also explores improving solutions by applying the developed nonlinear, constrained inverse dynamics model of the system formulated as a coupled dynamical problem based on the Newton–Euler (NE) approach and taking into account realistic environmental conditions. The approach is developed on the basis of rigid multi-body modelling and the concept that there is no change in the configuration of the system in the short time span of collisions.
Download or read book Walking Machines written by D. J. Todd and published by Springer. This book was released on 1985-06-30 with total page 200 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 Biologically Inspired Approaches for Locomotion Anomaly Detection and Reconfiguration for Walking Robots written by Bojan Jakimovski and published by Springer. This book was released on 2011-08-20 with total page 203 pages. Available in PDF, EPUB and Kindle. Book excerpt: The increasing presence of mobile robots in our everyday lives introduces the requirements for their intelligent and autonomous features. Therefore the next generation of mobile robots should be more self-capable, in respect to: increasing of their functionality in unforeseen situations, decreasing of the human involvement in their everyday operations and their maintenance; being robust; fault tolerant and reliable in their operation. Although mobile robotic systems have been a topic of research for decades and aside the technology improvements nowadays, the subject on how to program and making them more autonomous in their operations is still an open field for research. Applying bio-inspired, organic approaches in robotics domain is one of the methodologies that are considered that would help on making the robots more autonomous and self-capable, i.e. having properties such as: self-reconfiguration, self-adaptation, self-optimization, etc. In this book several novel biologically inspired approaches for walking robots (multi-legged and humanoid) domain are introduced and elaborated. They are related to self-organized and self-stabilized robot walking, anomaly detection within robot systems using self-adaptation, and mitigating the faulty robot conditions by self-reconfiguration of a multi-legged walking robot. The approaches presented have been practically evaluated in various test scenarios, the results from the experiments are discussed in details and their practical usefulness is validated.
Download or read book Multi objective Optimization for Speed and Stability of a Sony AIBO Gait written by Christopher A. Patterson and published by . This book was released on 2007 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book On the Controlling of Multi Legged Walking Robots on Stable and Unstable Ground written by Dariusz Grzelczyk and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this chapter, we developed and investigated numerically a general kinematic model of a multi-legged hybrid robot equipped with a crab-like and/or mammal-like legs. To drive the robot,Äôs limbs, a novel generator of gait was employed and tested. The simulation model developed in Mathematica is suitable for virtual study and visualization of the locomotion process. In contrast to our previous papers, in this study we focused especially on precise control of the position of the robot during walking in different directions. In our study we were able to simultaneously control all six spatial degrees of freedom of the robot,Äôs body, as well as all the robot,Äôs legs. Therefore, the investigated robot can be considered and used as a fully controlled walking Stewart platform. What is more, the used algorithm can also be successfully employed to coordinate and control all limbs of the robot on unstable or vibrating ground. As an example, it can be used to stabilize spatial position of the robot when the supporting ground becomes vibrating or unstable, and it will keep the robot stable and prevent it from falling over. Eventually, the developed simulation algorithms can be relatively simply adopted to control real constructions of different multi-legged robots.
Download or read book Quadrupedal Locomotion written by Pablo González de Santos and published by Springer Science & Business Media. This book was released on 2007-02-17 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: Walking machines have advantages over traditional vehicles, and have already accomplished tasks that wheeled or tracked robots cannot handle. Nevertheless, their use in industry and services is currently limited in scope. This book brings together methods and techniques that have been developed to deal with obstacles to wider acceptance of legged robots. Part I provides an historical overview. Part II concentrates on control techniques, as applied to Four-legged robots.
