Design and Gait Control of a Rollerblading Robot

We present the design and gait generation for an experimental ROLLERBLADER1. The ROLLERBLADER is a robot with a central platform mounted on omnidirectional casters and two 3 degree-of-freedom legs. A passive rollerblading wheel is attached to the end of each leg. The wheels give rise to nonholonomic constraints acting on the robot. The legs can be picked up and placed back on the ground allowing a combination of skating and walking gaits. We present two types of gaits for the robot. In the first gait, we allow the legs to be picked up and placed back on the ground while in the second, the wheels are constrained to stay on the ground at all times. Experimental gait results for a prototype robot are also presented

Dynamics and Generation of Gaits for a Planar Rollerblader

We develop the dynamic model for a planar ROLLERBLADER. The robot consists of a rigid platform and two planar, two degree-of-freedom legs with in-line skates at the foot. The dynamic model consists of two unicycles coupled through the rigid body dynamics of the planar platform. We derive the Lagrangian reduction for the ROLLERBLADING robot. We show the generation of some simple gaits that allow the platform to move forward and rotate by using cyclic motions of the two legs

Development and Field Testing of the FootFall Planning System for the ATHLETE Robots

The FootFall Planning System is a ground-based planning and decision support system designed to facilitate the control of walking activities for the ATHLETE (All-Terrain Hex-Limbed Extra-Terrestrial Explorer) family of robots. ATHLETE was developed at NASA's Jet Propulsion Laboratory (JPL) and is a large six-legged robot designed to serve multiple roles during manned and unmanned missions to the Moon; its roles include transportation, construction and exploration. Over the four years from 2006 through 2010 the FootFall Planning System was developed and adapted to two generations of the ATHLETE robots and tested at two analog field sites (the Human Robotic Systems Project's Integrated Field Test at Moses Lake, Washington, June 2008, and the Desert Research and Technology Studies (D-RATS), held at Black Point Lava Flow in Arizona, September 2010). Having 42 degrees of kinematic freedom, standing to a maximum height of just over 4 meters, and having a payload capacity of 450 kg in Earth gravity, the current version of the ATHLETE robot is a uniquely complex system. A central challenge to this work was the compliance of the high-DOF (Degree Of Freedom) robot, especially the compliance of the wheels, which affected many aspects of statically-stable walking. This paper will review the history of the development of the FootFall system, sharing design decisions, field test experiences, and the lessons learned concerning compliance and self-awareness

Stabilizability and Motion Tracking Conditions for Mechanical Nonholonomic Control Systems

This paper addresses formulation of stabilizability and motion tracking conditions for mechanical systems from the point of view of constraints put on them. We present a new classification of constraints, which includes nonholonomic constraints that arise in both mechanics and control. Based on our classification we develop kinematic and dynamic control models of systems subjected to these constraints. We demonstrate that a property of being a “hard-to-control” nonholonomic system may not be related to the nature of the constraints. It may result from the formulation of control objectives for a system. We examine two control objectives which are stabilization to the target equilibrium by a continuous static state feedback control and motion tracking. Theory is illustrated with examples of control objective formulations for systems with constraints of various types

Implementation of a Variable Duty Factor Controller on a Six-Legged Axi-Symmetric Walking Robot

Hexplorer is a six-legged walking robot developed at the University of Waterloo. The robot is controlled by a network of seven digital signal processors, six of which control three motors each, for a total of 18 motors. Brand new custom electronics were designed to house the digital signal processors and associated circuitry. A variable duty factor wave gait, developed by Yoneda et al. was simulated and implemented on the robot. Simulation required an in-depth kinematic analysis that was complicated by the mechanical design of parallel mechanism comprising the legs. These complications were handled in both simulation and implementation. However, due to mechanical issues Hexplorer walked for only one or two steps at a time

Quantifying Forearm Soft Tissue Motion and Shock Attenuation following Hand Impacts Consistent with Forward Falls using Massless Skin Surface Markers

The purpose of this thesis was twofold: 1) quantify planar (2D) displacement and velocity of, and the amount of shock attenuated by, the forearm soft tissues following a forward fall impact; and 2) compare two massless skin surface marker designs with different uniformity and visual contrast (i.e., single layer, uniform (SLU) design; stacked, non-uniform (SNU) design) in terms of how well they can be tracked over varying skin pigmentation using automated motion capture software. Simulated forward fall impacts were performed by two groups of participants (skin pigmentation: light – 9F, 8M; dark – 9F, 6M) using a torso-release apparatus, in which a high speed camera (5000 f/s) captured planar motion of the right forearm. Automated motion tracking software (ProAnalyst®) was used to quantify displacement, velocity, and shock attenuation capacity of the forearm soft tissue from manually digitized markers. Overall, the greatest mean peak soft tissue displacement (1.47 cm) and velocity (112.8 cm/s) occurred in the distal direction in proximal regions of the forearm where more soft tissue is distributed. Soft tissue displacement and velocity exhibited similar trends, increasing from distal to proximal regions of the forearm, while impact shock accelerations were not attenuated in the forearm, but instead increased by 76%. Apart from proximal rebound distance, soft tissue kinematics between females and males did not significantly differ (p \u3e 0.05). Conversely, the effects of specific tissue masses (i.e., bone mineral content, fat mass, lean mass, and wobbling mass) on tissue kinematics varied between the sexes. Significant differences were found between marker designs for displacement, rebound distance, and velocity (p ≤ 0.05), wherein the SLU design consistently produced higher values than the SNU design

Life patterns : structure from wearable sensors

Thesis (Ph. D.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, February 2003.Includes bibliographical references (leaves 123-129).In this thesis I develop and evaluate computational methods for extracting life's patterns from wearable sensor data. Life patterns are the reoccurring events in daily behavior, such as those induced by the regular cycle of night and day, weekdays and weekends, work and play, eating and sleeping. My hypothesis is that since a "raw, low-level" wearable sensor stream is intimately connected to the individual's life, it provides the means to directly match similar events, statistically model habitual behavior and highlight hidden structures in a corpus of recorded memories. I approach the problem of computationally modeling daily human experience as a task of statistical data mining similar to the earlier efforts of speech researchers searching for the building block that were believed to make up speech. First we find the atomic immutable events that mark the succession of our daily activities. These are like the "phonemes" of our lives, but don't necessarily take on their finite and discrete nature. Since our activities and behaviors operate at multiple time-scales from seconds to weeks, we look at how these events combine into sequences, and then sequences of sequences, and so on. These are the words, sentences and grammars of an individual's daily experience. I have collected 100 days of wearable sensor data from an individual's life. I show through quantitative experiments that clustering, classification, and prediction is feasible on a data set of this nature. I give methods and results for determining the similarity between memories recorded at different moments in time, which allow me to associate almost every moment of an individual's life to another similar moment. I present models that accurately and automatically classify the sensor data into location and activity.(cont.) Finally, I show how to use the redundancies in an individual's life to predict his actions from his past behavior.by Brian Patrick Clarkson.Ph.D

Representations: Doing Asian American Rhetoric

Despite tremendous growth in attention to and scholarship about Asian Americans and their cultural work, little research has emerged that focuses directly on Asian American rhetoric. Representations: Doing Asian American Rhetoric addresses this need by examining the systematic, effective use of symbolic resources by Asians and Asian Americans in social, cultural, and political contexts. Such rhetoric challenges, disrupts, and transforms the dominant European American rhetoric and it commands a sense of unity or collective identity. However, such rhetoric also embodies internal differences and even contradictions, as each specific communicative situation is informed and inflected by particularizing contexts, by different relations of asymmetry, and, most simply put, by heterogeneous voices. The essays in Representations: Doing Asian American Rhetoric examine broadly the histories, theories, and practices of Asian American rhetoric, situating rhetorical work across the disciplines where critical study of Asian Americans occurs: Asian American studies, rhetoric and composition, communication studies, and English studies. These essays address the development and adaptation of classical rhetorical concepts such as ethos and memory, modern concepts such as identification, and the politics of representation through a variety of media and cultural texts. As these essays collectively argue, Asian American rhetoric not only reflects and responds to existing social and cultural conditions and practices, but also interacts with and impacts such conditions and practices. To the extent it does, it becomes a rhetoric of becomingý-a rhetoric that is always in the process of negotiating with, adjusting to, and yielding an imagined identity and agency that is Asian American.https://digitalcommons.usu.edu/usupress_pubs/1163/thumbnail.jp