Sliding and hopping gaits for the underactuated Acrobot

Berkemeier, M.D.; Fearing, Ronald S.

doi:10.1109/70.704235

Cited by 88 publications

(32 citation statements)

References 26 publications

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“…In addition, the relation of the swing phase zero dynamics and the high-gain limit of the closed-loop hybrid system is analyzed for the controller of (6.97) and (6.99). 17 This is really a partial map, with domain spelled out in Section 4.4.3. 18 A numerical simulator is used to compute an approximation ofρ.…”

Section: Apply the Impact Model To Xmentioning

confidence: 99%

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Feedback Control of Dynamic Bipedal Robot Locomotion

Westervelt¹,

et al. 2018

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To our loved ones. A tous ceux que nous aimons. DRAFT --May 15, 2007 --DRAFT --May 15, 2007 --DR PrefaceThe objective of this book is to present systematic methods for achieving stable, agile and efficient locomotion in bipedal robots. The fundamental principles presented here can be used to improve the control of existing robots and provide guidelines for improving the mechanical design of future robots. The book also contributes to the emerging control theory of hybrid systems. Models of legged machines are fundamentally hybrid in nature, with phases modeled by ordinary differential equations interleaved with discrete transitions and reset maps. Stable walking and running correspond to the design of asymptotically stable periodic orbits in these hybrid systems and not equilibrium points. Past work has emphasized quasi-static stability criteria that are limited to flat-footed walking. This book represents a concerted effort to understand truly dynamic locomotion in planar bipedal robots, from both theoretical and practical points of view.The emphasis on sound theory becomes evident as early as Chapter 3 on modeling, where the class of robots under consideration is described by lists of hypotheses, and further hypotheses are enumerated to delineate how the robot interacts with the walking surface at impact, and even the characteristics of its gait. This careful style is repeated throughout the remainder of the book, where control algorithm design and analysis are treated. At times, the emphasis on rigor makes the reading challenging for those less mathematically inclined. Do not, however, give up hope! With the exception of Chapter 4 on the method of Poincaré sections for hybrid systems, the book is replete with concrete examples, some very simple, and others quite involved. Moreover, it is possible to cherry-pick one's way through the book in order to "just figure out how to design a controller while avoiding all the proofs." This is mapped out below and in Appendix A.The practical side of the book stems from the fact that it grew out of a project grounded in hardware. More details on this are given in the acknowledgements, but suffice it to say that every stage of the work presented here has involved the interaction of roboticists and control engineers. This interaction has led to a control theory that is closely tied to the physics of bipedal robot locomotion. The importance and advantage of doing this was first driven home to one of the authors when a multipage computation involving the Frobenius Theorem produced a quantity that one of the other authors identified as angular momentum, and she could reproduce the desired result in two lines! Fortunately, the power of control theory produced its share of eye-opening moments on the robotic side of the house, such as when days and DRAFT --May 15, 2007 --DRAFT --May 15, 2007 --DR days of simulations to tune a "physically-based" controller were replaced by a ten minute design of a PI-controller on the basis of a restricted Poincaré map, and the controller worked l...

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Section: Apply the Impact Model To Xmentioning

confidence: 99%

“…3.4. In the swing phase, the model corresponds to that of the Acrobot [17,93,215] with symmetric links. It is very similar to the simplest walking model of Garcia et al [84], except that the mass is distributed along the leg as opposed to being concentrated at the hip.…”

Section: The Acrobot As a Walker: A Two-link Example Modelmentioning

confidence: 99%

Feedback Control of Dynamic Bipedal Robot Locomotion

Westervelt¹,

et al. 2018

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“…Indeed, research in this area has led to the development of small robots capable of both self stabilization and hopping (Zhao et al, 2009). Prior studies on hopping have also addressed mechanics of simple, singlejoint actuated robots that were able to achieve stable hopping gaits (Berkemeier and Fearing, 1998), and single-hop robots have been constructed using pneumatic muscle actuators (Niiyama et al, 2007). It has also been shown that combining several hops was more energy efficient than a single, powerful hop, while producing the same jumping height (Aguilar et al, 2012).…”

Section: Related Workmentioning

confidence: 99%

Exploring the Role of the Tail in Bipedal Hopping through Computational Evolution

Moore

Gutmann

McGowan

et al. 2013

Advances in Artificial Life, ECAL 2013

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Bipedal hopping has evolved as a mode of terrestrial locomotion in relatively few mammalian species. Despite large differences in body size, habitat use, and having evolved independently, all species that use bipedal hopping have remarkably similar limb morphology and posture. In addition, these species all have relatively long tails, presumably to assist in maintaining stability. However, the evolution of this behavior, and specifically the role of the tail, is not well understood. In this paper, we explore the evolution of bipedal hopping in a simulated animat, using a relatively simple musculoskeletal model and a rigid-body physics simulation environment. Results indicate that characteristically different hopping gaits evolve with alterations to the morphology, including the structure and actuation of the tail. Many of the the results are consistent with behaviors and morphologies observed in natural organisms. However, in some cases effective hopping evolved despite key differences from nature, potentially inspiring new design approaches in robotic and biomechanical systems.

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“…The capacity of controlling underactuated robots using their dynamical coupling characteristics is modelled in [7,8]. Finally, let us specially mention interesting works around Acrobot-like systems (these are 2 dof robots, with a single actuator either at the hip -the Pendubot -or at the knee , and submitted to the gravity, contrary to previous cases): [16] proposes a decoupling and partial feedback linearization scheme with control switching; [17] uses two control schemes for a hopping Acrobot, one for the flight phase and the other one in the stance phase. A last point to be mentionned is the fact that the active control of a compass robot using the hip actuator as done in [20] is a problem which can be viewed as a special case of control of an underactuated double pendulum.…”

Section: A Brief Tour Of the Literaturementioning

confidence: 99%

Can an underactuated leg with a passive spring at the knee achieve a ballistic step?

Espiau

Guigues

Pissard-Gibollet

2000

Experimental Robotics VI

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Abstract:In this paper, we present the design and the results of a control scheme aimed at moving an underactuated double pendulum simulating a leg. The system is actuated at the hip and includes a spring at the knee. It interacts with the grou nd, which is in fact a treadmill, through a telescopic foot made of a linear spri ng and a damper. The control scheme is different in the 2 phases, swing and stance, and a repetitive step is achieved by switching between these two controls. The paper describes the used models, the control algorithms and their implementation. It pr esents also experimental results of the approach. Key-words:

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Sliding and hopping gaits for the underactuated Acrobot

Cited by 88 publications

References 26 publications

Feedback Control of Dynamic Bipedal Robot Locomotion

Feedback Control of Dynamic Bipedal Robot Locomotion

Exploring the Role of the Tail in Bipedal Hopping through Computational Evolution

Can an underactuated leg with a passive spring at the knee achieve a ballistic step?

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