Dynamic Walking on Uneven Terrains with Passivity-Based Bipedal Robots

Dynamic walking on bipedal robots has evolved from an idea in science fiction to a practical reality. This is due to continued progress in three key areas: a mathematical understanding of locomotion, the computational ability to encode this mathematics through optimization, and the hardware capable of realizing this understanding in practice. In this context, this review outlines the end-to-end process of methods that have proven effective in the literature for achieving dynamic walking on bipedal robots. We begin by introducing mathematical models of locomotion, from reduced-order models that capture essential walking behaviors to hybrid dynamical systems that encode the full-order continuous dynamics along with discrete foot-strike dynamics. These models form the basis for gait generation via (nonlinear) optimization problems. Finally, models and their generated gaits merge in the context of real-time control, wherein walking behaviors are translated to hardware. The concepts presented are illustrated throughout in simulation, and experimental instantiations on multiple walking platforms are highlighted to demonstrate the ability to realize dynamic walking on bipedal robots that is both agile and efficient. Expected final online publication date for the Annual Review of Control, Robotics, and Autonomous Systems, Volume 4 is May 3, 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

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A controller for dynamic walking in bipedal robots

2009 IEEE/RSJ International Conference on Intelligent Robots and Systems ◽

10.1109/iros.2009.5354840 ◽

2009 ◽

Cited By ~ 4

Author(s):

David J. Braun ◽

Michael Goldfarb

Keyword(s):

Dynamic Walking ◽

Bipedal Robots

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A Control Framework for Anthropomorphic Biped Walking Based on Stabilizing Feedforward Trajectories

Volume 1: Advances in Control Design Methods, Nonlinear and Optimal Control, Robotics, and Wind Energy Systems; Aerospace Applications; Assistive and Rehabilitation Robotics; Assistive Robotics; Battery and Oil and Gas Systems; Bioengineering Applications; Biomedical and Neural Systems Modeling, Diagnostics and Healthcare; Control and Monitoring of Vibratory Systems; Diagnostics and Detection; Energy Harvesting; Estimation and Identification; Fuel Cells/Energy Storage; Intelligent Transportation ◽

10.1115/dscc2016-9851 ◽

2016 ◽

Cited By ~ 1

Author(s):

Siavash Rezazadeh ◽

Robert D. Gregg

Keyword(s):

Stable Limit Cycle ◽

Humanoid Robots ◽

Stable Limit ◽

Dynamic Walking ◽

Bipedal Robots ◽

Bipedal Robot ◽

External Perturbations ◽

Control Framework ◽

Zero Moment ◽

The Stability

Although dynamic walking methods have had notable successes in control of bipedal robots in the recent years, still most of the humanoid robots rely on quasi-static Zero Moment Point controllers. This work is an attempt to design a highly stable controller for dynamic walking of a human-like model which can be used both for control of humanoid robots and prosthetic legs. The method is based on using time-based trajectories that can induce a highly stable limit cycle to the bipedal robot. The time-based nature of the controller motivates its use to entrain a model of an amputee walking, which can potentially lead to a better coordination of the interaction between the prosthesis and the human. The simulations demonstrate the stability of the controller and its robustness against external perturbations.

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An experimental study of passive dynamic walking

Robotica ◽

10.1017/s0263574703005563 ◽

2004 ◽

Vol 22 (3) ◽

pp. 251-262 ◽

Cited By ~ 8

Author(s):

Q. Wu ◽

N. Sabet

Keyword(s):

Surface Friction ◽

Step Length ◽

Gait Pattern ◽

Dynamic Walking ◽

Bipedal Robots ◽

Passive Dynamic Walking ◽

Gait Patterns ◽

Flat Feet ◽

Walking Mechanism ◽

Walking Efficiency

A two-straight-legged walking mechanism with flat feet is designed and built to study the passive dynamic gait. It is shown that the mechanism having flat feet can exhibit passive dynamic walking as those with curved feet, but the walking efficiency is significantly lower. It is also shown that the balancing mass and its orientation are effective for controlling side-to-side rocking and yaw, which have significant effects on steady walking. The effects of various parameters on the gait patterns are also studied. lt is shown that changes in the ramp angle have the most dominant effect on the gait pattern as compared with the changes in the hip mass, ramp surface friction and size of the flat feet. More specifically, as the ramp angle increases, the step length increases while the range of the side-to side rocking angle decreases and the step length dictates the walking speed and the gravitational power. Another finding, is that adding a hip mass improves the walking efficiency by allowing the mechanism to walk on a flatter ramp. This research enables us to gain a better understanding of the mechanics of walking. Such an understanding will have a direct impact on better design of prostheses and on the active control aspects of bipedal robots.

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Precision Circular Walking of Bipedal Robots

Volume 2: 32nd Mechanisms and Robotics Conference, Parts A and B ◽

10.1115/detc2008-49538 ◽

2008 ◽

Cited By ~ 2

Author(s):

Karl J. Muecke ◽

Dennis W. Hong ◽

Seungchul Lim

Keyword(s):

Inverse Kinematics ◽

Coordinate Frame ◽

Ground Contact ◽

Dynamic Walking ◽

Bipedal Robots ◽

Dynamic Simulations ◽

Constraint Equations ◽

Forward And Inverse Kinematics ◽

Zero Moment ◽

Joint Motions

Whenever bipedal robots need to make turns, the ability to walk stably and precisely along a circular curve of an arbitrary radius will be quite beneficial. This motivates us to derive new Zero Moment Point (ZMP) constraint equations with respect to a rotating coordinate frame, seek appropriate dynamic gaits based on them, and address the forward and inverse kinematics. After the relevant body and feet trajectories are fully prescribed, joint motions are determined using the inverse kinematics. A set of dynamic walking patterns including the transient are herein proposed and applied to an exemplificative case of turning locomotion. Conclusively, dynamic simulations prove the patterns to be successful even in the presence of distributed-mass and ground contact effects.

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