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Author: Aaron Murdock Hoover Publisher: ISBN: Category : Languages : en Pages : 232
Book Description
This thesis explores milli- and meso-scale legged robot design and fabrication with compliant mechanisms. Our approach makes use of a process that integrates compliant flexure hinges and rigid links to form parallel kinematic structures through the folding of flat-fabricated sheets of articulated parts. Using screw theory, we propose the formulation of an equivalent mechanism compliance for a class of parallel mechanisms, and we use that compliance to evaluate a scalar performance metric based on the strain energy stored in a mechanism subjected to an arbitrary load. Results from the model are supported by experimental measurements of a representative mechanism. With the insight gained from the kinematic mechanism design analysis, we propose and demonstrate compliant designs for two six-legged robots comprising the robotic, autonomous, crawling hexapod (RoACH) family of robots. RoACH is a two degree of freedom, 2.4 gram, 3 cm long robot capable of untethered, sustained, steerable locomotion. RoACH's successor, DynaRoach, is 10 cm long, has one actuated degree of freedom and is capable of running speeds of up to 1.4 m/s. DynaRoACH employs compliant legs to help enable dynamic running and maneuvering and is three orders of magnitude more efficient than its milli-scale predecessor. We experimentally demonstrate the feasibility of a biologically-inspired approach to turning control and dynamic maneuvering by adjusting leg stiffness. While the result agrees qualitatively with predictions from existing reduced order models, initial data suggest the full 3-dimensional dynamics play an important role in six-legged turning.
Author: Aaron Murdock Hoover Publisher: ISBN: Category : Languages : en Pages : 232
Book Description
This thesis explores milli- and meso-scale legged robot design and fabrication with compliant mechanisms. Our approach makes use of a process that integrates compliant flexure hinges and rigid links to form parallel kinematic structures through the folding of flat-fabricated sheets of articulated parts. Using screw theory, we propose the formulation of an equivalent mechanism compliance for a class of parallel mechanisms, and we use that compliance to evaluate a scalar performance metric based on the strain energy stored in a mechanism subjected to an arbitrary load. Results from the model are supported by experimental measurements of a representative mechanism. With the insight gained from the kinematic mechanism design analysis, we propose and demonstrate compliant designs for two six-legged robots comprising the robotic, autonomous, crawling hexapod (RoACH) family of robots. RoACH is a two degree of freedom, 2.4 gram, 3 cm long robot capable of untethered, sustained, steerable locomotion. RoACH's successor, DynaRoach, is 10 cm long, has one actuated degree of freedom and is capable of running speeds of up to 1.4 m/s. DynaRoACH employs compliant legs to help enable dynamic running and maneuvering and is three orders of magnitude more efficient than its milli-scale predecessor. We experimentally demonstrate the feasibility of a biologically-inspired approach to turning control and dynamic maneuvering by adjusting leg stiffness. While the result agrees qualitatively with predictions from existing reduced order models, initial data suggest the full 3-dimensional dynamics play an important role in six-legged turning.
Author: Alessandro Gasparetto Publisher: Springer ISBN: 3030003655 Category : Technology & Engineering Languages : en Pages : 468
Book Description
This volume contains the Proceedings of the 4th IFToMM Symposium on Mechanism Design for Robotics, held in Udine, Italy, 11-13 September, 2018. It includes recent advances in the design of mechanisms and their robotic applications. It treats, among others, the following topics: mechanism design, mechanics of robots, parallel manipulators, actuators and their control, linkage and industrial manipulators, innovative mechanisms/robots and their applications. This book can be used by students, researchers and engineers in the relevant areas of mechanisms, machines and robotics.
Author: Duncan Haldane Publisher: ISBN: Category : Languages : en Pages : 93
Book Description
The development of legged robots can serve two purposes. The first is to enable more mobility for robotic platforms and allow them greater flexibility for moving through complex real-world environments. The second is that the legged robot is a scientific tool. It can be used to design new experiments that drive insights both for the development of new robotic platforms and the characteristic of animal locomotors from which they are inspired. This work presents a design methodology that targets the creation of extreme robotic locomotors. These are robots that outperform all others at a particular task. They are used to study locomotion at the edge of the current performance envelope for robotic systems. The design methodology focuses on maximizing the power-density of the platform. We apply it to create first a rapid running robot, the X2-VelociRoACH, and two versions of a jumping robot, Salto and Salto-1P. In all of these robots, we centralize the actuation such that one actuator provides all the power for the energetic locomotory tasks. A kinematic coupling is designed for each platform, such that the correct behavior (running or jumping) happens by default when the energetic actuator is driven open-loop. The design methodology successfully created two robots at the edge of their respective performance envelopes. The X2-VelociRoACH is a 54 gram experimental legged robot developed with this methodology that was developed to test hypotheses about running with unnaturally high stride frequencies. It is capable of running at stride frequencies up to 45 Hz, and velocities up to 4.9 m/s, making it the fastest legged robot relative to size. The top speed of the robot was limited by structural failure. High-frequency running experiments with the robot shows that the power required to cycle its running appendages increase cubically with the stride rate. Our findings show that although it is possible to further increase the maximum velocity of a legged robot with the simple strategy of increasing stride frequency, considerations must be made for the energetic demands of high stride rates. For the development of the jumping robot Salto, we first devise the vertical jumping agility metric to identify a model animal system for inspiration. We found the most agile animals outperform the most agile robots by a factor of two. The animal with the highest vertical jumping agility, the galago (Galago senegalensis), is known to use a power-modulating strategy to obtain higher peak power than that of muscle alone. Few previous robots have used series-elastic power modulation (achieved by combining series-elastic actuation with variable mechanical advantage), and because of motor power limits, the best current robot has a vertical jumping agility of only 55% of a galago. Through use of a specialized leg mechanism designed to enhance power modulation, we constructed a jumping robot that achieved 78% of the vertical jumping agility of a galago. The leg mechanism also has constraints which assure rotation-free jumping motion by default. Agile robots can explore venues of locomotion that were not previously attainable. We demonstrate this with a wall jump, where the robot leaps from the floor to a wall and then springs off the wall to reach a net height that is greater than that accessible by a single jump. Our results show that series-elastic power modulation is an actuation strategy that enables a clade of vertically agile robots. We extend the work with Salto to see how the locomotory capacity of an extreme robotic locomotor can be extended without compromising the power density of the platform. Salto-1P uses aerodynamic thrusters and an inertial tail to control its attitude in the air. A linearized Raibert step controller was sufficient to enable unconstrained in-place hopping and forwards-backwards locomotion with external position feedback. We present studies of extreme jumping locomotion in which the robot spends just 7.7% of its time on the ground, experiencing accelerations of 14 times earth gravity in its stance phase. An experimentally collected dataset of 772 observed jumps was used to establish the range of achievable horizontal and vertical impulses for Salto-1P.
Author: Sangbae Kim Publisher: ISBN: 9781680832570 Category : Artificial legs Languages : en Pages : 73
Book Description
Animals exhibit remarkable locomotion capabilities across land, sea, and air in every corner of the world. On land, legged morphologies have evolved to manifest magnificent mobility over a wide range of surfaces. From the ability to use footholds for navigating a challenging mountain pass, to the capacity for running on a sandy beach, the adaptability afforded through legs motivates their prominence as the biologically preferred method of ground transportation. Inspired by these achievements in nature, robotics engineers have strived for decades to achieve similar dynamic locomotion capabilities in legged machines. Learning from animals' compliant structures and ways of utilizing them, engineers developed numerous novel mechanisms that allow for more dynamic, more efficient legged systems. These newly emerging robotic systems possess distinguishing mechanical characteristics in contrast to manufacturing robots in factories and pave the way for a new era of mobile robots to serve our society. Realizing the full capabilities of these new legged robots is a multi-factorial research problem, requiring coordinated advances in design, control, perception, state estimation, navigation and other areas. This review article concentrates particularly on the mechanical design of legged robots, with the aim to inform both future advances in novel mechanisms as well as the coupled problems described above. Essential technological components considered in mechanical design are discussed through historical review. Emerging design paradigms are then presented, followed by perspectives on their future applications.
Author: Jian S. Dai Publisher: Springer ISBN: 9781447171850 Category : Technology & Engineering Languages : en Pages : 900
Book Description
"A selection of key papers presented in The Second ASME/IFToMM International Conference on Reconfigurable Mechanisms and Robots (ReMAR 2012) held on 9th-11th July 2012 in Tianjin, China"--Page 4 of cover.
Author: Metin Sitti Publisher: MIT Press ISBN: 0262341018 Category : Technology & Engineering Languages : en Pages : 305
Book Description
The first textbook on micron-scale mobile robotics, introducing the fundamentals of design, analysis, fabrication, and control, and drawing on case studies of existing approaches. Progress in micro- and nano-scale science and technology has created a demand for new microsystems for high-impact applications in healthcare, biotechnology, manufacturing, and mobile sensor networks. The new robotics field of microrobotics has emerged to extend our interactions and explorations to sub-millimeter scales. This is the first textbook on micron-scale mobile robotics, introducing the fundamentals of design, analysis, fabrication, and control, and drawing on case studies of existing approaches. The book covers the scaling laws that can be used to determine the dominant forces and effects at the micron scale; models forces acting on microrobots, including surface forces, friction, and viscous drag; and describes such possible microfabrication techniques as photo-lithography, bulk micromachining, and deep reactive ion etching. It presents on-board and remote sensing methods, noting that remote sensors are currently more feasible; studies possible on-board microactuators; discusses self-propulsion methods that use self-generated local gradients and fields or biological cells in liquid environments; and describes remote microrobot actuation methods for use in limited spaces such as inside the human body. It covers possible on-board powering methods, indispensable in future medical and other applications; locomotion methods for robots on surfaces, in liquids, in air, and on fluid-air interfaces; and the challenges of microrobot localization and control, in particular multi-robot control methods for magnetic microrobots. Finally, the book addresses current and future applications, including noninvasive medical diagnosis and treatment, environmental remediation, and scientific tools.
Author: Marc H. Raibert Publisher: MIT Press ISBN: 9780262181174 Category : Computers Languages : en Pages : 254
Book Description
This book, by a leading authority on legged locomotion, presents exciting engineering and science, along with fascinating implications for theories of human motor control. It lays fundamental groundwork in legged locomotion, one of the least developed areas of robotics, addressing the possibility of building useful legged robots that run and balance. The book describes the study of physical machines that run and balance on just one leg, including analysis, computer simulation, and laboratory experiments. Contrary to expectations, it reveals that control of such machines is not particularly difficult. It describes how the principles of locomotion discovered with one leg can be extended to systems with several legs and reports preliminary experiments with a quadruped machine that runs using these principles. Raibert's work is unique in its emphasis on dynamics and active balance, aspects of the problem that have played a minor role in most previous work. His studies focus on the central issues of balance and dynamic control, while avoiding several problems that have dominated previous research on legged machines. Marc Raibert is Associate Professor of Computer Science and Robotics at Carnegie-Mellon University and on the editorial board of The MIT Press journal, Robotics Research. Legged Robots That Balanceis fifteenth in the Artificial Intelligence Series, edited by Patrick Winston and Michael Brady.
Author: Aaron Murdock Hoover
Author: Aaron Murdock Hoover
Author: Alessandro Gasparetto
Author: Duncan Haldane
Author: Sangbae Kim
Author: Marco Hutter
Author: Sung-Ho Park
Author: Jian S. Dai
Author: Sŏng-ho Pak
Author: Metin Sitti
Author: Marc H. Raibert