Quasi optimal sagittal gait of a biped robot with a new structure of knee joint

The design of humanoid robots has been a tricky challenge for several years. Due to the kinematic complexity of human joints, their movements are notoriously difficult to be reproduced by a mechanism. The human knees allow movements including rolling and sliding, and therefore the design of new bioinspired knees is of utmost importance for the reproduction of anthropomorphic walking in the sagittal plane. In this article, the kinematic characteristics of knees were analyzed and a mechanical solution for reproducing them is proposed. The geometrical, kinematic and dynamic models are built together with an impact model for a biped robot with the new knee kinematic. The walking gait is studied as a problem of parametric optimization under constraints. The trajectories of walking are approximated by mathematical functions for a gait composed of single support phases with impacts. Energy criteria allow comparing the robot provided with the new rolling knee mechanism and a robot equipped with revolute knee joints. The results of the optimizations show that the rolling knee brings a decrease of the sthenic criterion. The comparisons of torques are also observed to show the difference of energy distribution between the actuators. For the same actuator selection, these results prove that the robot with rolling knees can walk longer than the robot with revolute joint knees.ANR R2A

Efficiency of the built environment: Interdependencies in transportation, development form and public health

Retrofitting existing neighborhoods and communities to remove barriers to walking and allow residents to choose walking as a mode of transportation has the potential to both stabilize energy used for transportation and transportation infrastructure and provide physical activity for improved health, shifting the energy used for transportation from cars to people. This study brings together community-based research, an interdisciplinary team approach, and multi-level modeling to investigate how community design impacts transportation behavior in the context of smaller, northeastern cities. Ten neighborhoods of varying design, connectivity, proximity to services, and average income were selected in each of the cities for a total of twenty neighborhoods studied. A survey of neighborhood residents provided demographic, health, and transportation behavior information. The built environment within the neighborhoods was analyzed using field visits and published GIS data. Data analysis included multi-level modeling to account for the within-neighborhood clustered design of data collection. Working together with the people for whom the results were intended allowed for use of a greater network of contacts for project development and implementation, which helped greatly. Involving municipal and regional authorities throughout the project increased the chances that results will be useful and will reach residents, and resulted in increased communication between the authorities themselves. Presence of sidewalks and intersections were found to be associated with the number of destinations respondents reported walking. Municipalities that would like to increase walking for public health or energy use reduction should investigate improving the condition and availability of sidewalks in neighborhoods, increasing connectivity of pedestrian ways, and improving safety and perceived security at intersections. Age appeared to be the most important demographic factor in decisions to walk, more important than self-reported health or income. Helping the elderly, as they age in place, to continue to feel secure through improved walking surfaces and walking environments could be a fruitful focus of municipal programs and initiatives

Cuba, New Mexico Trails, Park and Walkability Workshop

The purpose of this workshop was to provide an opportunity for community members and topic area experts to join together and assess the walking and activity opportunities in the community and to provide recommendations for ways to make the community an easier and safer place to be physically active. Fortyfive individuals attended the walkability workshop and learned about creative solutions other communities have used to: solve traffic and pedestrian challenges; design trails for people of all abilities; increase safety of walking routes to school; and make park improvements for increased physical activity

Leg Coordination during Walking in Insects

Locomotion depends on constant adaptation to different requirements of the environment. An appropriate temporal and spatial coordination of multiple body parts is necessary to achieve a stable and adapted behavior. Until now it is unclear how the neuronal structures can achieve these meaningful adaptations. The exact role of the nervous system, muscles and mechanical constrains are not known. By using preparations in which special forms of adaptations are considered under experimental conditions that selectively exclude external influences, like mechanical interactions through the ground or differences in body mass, one can draw conclusions about the organization of the respective underlying neuronal structures. In the present thesis, four different publications are presented, giving evidence of mechanisms of temporal or spatial coordination of leg movements in the stick insect Carausius morosus and the fruit fly Drosophila melanogaster during different experimental paradigms. At first, state dependent local coordinating mechanisms are analyzed. Electromyographic measurements of the three major antagonistic leg muscle pairs of the forward and backward walking stick insect are evaluated. It becomes evident that only the motor activity of the most proximal leg joint is changed when walking direction is changed from forward to backward, which demonstrates that the neuronal networks driving movement in each individual leg seem to be organized in a modular structure. In the second part mechanisms that influence movement speed of the individual leg and coordination of speed between the different legs of the stick insect come into focus. Electrophysiological and behavioral experiments with the intact and reduced stick insect were used to examine relationships between the velocity of a stepping front leg and neuronal activity in the mesothoracic segment as well as correlations between the stepping velocities of different legs during walks with constant velocity or with distinct accelerations. It was shown that stepping velocity of single legs were not reflected in motoneuron activity or stepping velocity of another leg. Only when an increase in walking speed was induced, clear correlation in the stepping velocities of the individual legs was found. Subsequently, the analysis of changes in temporal leg coordination during different walking speeds in the fruit fly reveals that the locomotor system of Drosophila can cover a broad range of walking speeds and seems to follow the same rules as the locomotor system of the stick insect. Walking speed is increased by modifying stance duration, whereas swing duration and step amplitude remain largely unchanged. Changes in inter-leg coordination are gradually and systematically with walking speed and can adapt to major biomechanical changes in its walking apparatus. In the final part it was the aim to understand the role of neuronal mechanisms for the orientation and spatial coordination of foot placement in the stick insect. Placement of middle and hind legs with respect to the position of their respective rostrally neighboring leg were analyzed under two different conditions. Segment and state dependent differences in the aiming accuracy of the middle and hind legs could be shown, which indicate differences in the underlying neuronal structures in the different segments and the importance of movement in the target leg for the processing of the position information. Taken together, common principles in inter-leg coordination where found, like similarities between different organisms and segment specific or state dependent modifications in the walking system. They can be interpreted as evidence for a highly adaptive and modular design of the underlying neuronal structures

The power exerted by urban atmosphere over our choice of walk

International audienceResearch presented here was financed by the National Research Agency (ANR) between 2005 and 2007. It brought together sociologists, architects and town planners around the question of the prerequisites for city-dwellers to decide to walk in town? Four districts, two in Grenoble (France) and two in Geneva (Switzerland), served as a basis for field work in three phases: surveys combining an architectural and sensory approach to the terrain; interviews with users; and ethnographic observations of walking practice. The results of the research throw doubt on the spatialist approach, still influential in architecture, which maintains that space determines usage. The findings suggest the need for a reappraisal of the power exerted by atmosphere over walking and urban practices. Atmosphere, by influencing both registers of walking (doing and experiencing), demonstrably contributes to the walkability of a place, just as much as its design does

Walking the path together: creating an instructional design team to elevate learning

There is a growing trend in academic libraries to enlist librarians with instructional design experience to assist with the opportunities and challenges of developing information literacy instruction both in-person and for online environments. In doing so, many institutions look for an individual who has the knowledge and skills to design, develop, and deploy elearning objects while also taking on more traditional public service responsibilities. Recognizing the varied expertise of instructional designers and the various skills associated with the development of eLearning objects such as sound instructional design practices, technology proficiencies, creativity and graphic arts, our institution has sought to create a team of instructional design librarians. The result has been the ability to create innovative and effective in-person and online instruction across the organization. Attendees will learn how two instructional design librarians are able to systematically work together to address the instructional design needs of a large university library

A physical activity program to mobilize older people: A practical and sustainable approach

Purpose: Despite the documented benefits of physical activity, it remains difficult to motivate older adults to start and maintain regular physical activity. This study tested an innovative intervention for mobilizing older adults into a neighborhood-based walking program. Design and Methods: Researchers recruited a total of 260 healthy but insufficiently active adults aged 65 to 74 years and randomly selected from the Australian electoral roll from 30 Perth metropolitan neighborhoods. Social cognitive theory guided the design of the program. Researchers collected both qualitative and quantitative data to inform the development, together with ongoing process evaluation. Results: A total of 65% of participants completed the program. Their mean weekly walking time for recreation increased by about 100 min, and 80% of participants reported that they would continue to walk twice per week upon program completion. Implications: This practical program is potentially effective and sustainable with respect to mobilizing physically inactive older people

Structural Origins of the Stiffness and Work Contributions of the Human Foot

Human foot mechanics have been extensively studied over the last century to understand human evolution and treat foot pathologies.Much of this understanding has centered on the foot\u27s longitudinal arch that runs from heel to toe, especially its role in making human feet stiff enough to withstand many times our bodyweight during walking and running. But numerous studies on foot biomechanics, orthopedic surgical reconstructions, and human evolution point to substantial gaps in the understanding based on the longitudinal arch alone. In this thesis, I present two new findings related to foot stiffness and how it produces the mechanical power needed for propulsion. First, I show that the transverse arch that runs across its width contributes more to foot stiffness than the longitudinal arch. Second, I show that a mechanism involving the plantar fascia and the longitudinal arch, called the windlass mechanism, has no effect on stiffness as previously assumed. Instead, it helps transmit power from muscles outside the foot to locations within the foot for efficient walking. These findings hinge upon a combination of mathematical models, mechanical foot models, mechanical tests on cadaveric feet, and measurements on live walking and running human volunteers. Together, these studies show how the foot\u27s function emerges from the combined roles of the longitudinal and transverse arches, and how those features may have evolved to enable human walking and running. After an introduction in chapter 1 to the current understanding of foot biomechanics and evolution, chapter 2 will present a series of studies using mechanical foot mimics and three-point bending tests in cadaveric human feet to show how the curvature of the transverse arch contributes to sagittal plane stiffness.Chapter 3 extends this result to in vivo foot stiffness measurements in walking humans and shows that despite active muscle contraction changes during walking, the transverse arch continues to influence sagittal foot stiffness. The evidence indicates that the evolution of a transverse arch played a key role in human evolution by enabling a stiff foot for propulsion. Chapter 4 turns to the longitudinal arch with an experimental examination of the windlass mechanism in walking and running humans, and finds that the windlass does not increase foot stiffness but plays an important role in power transmission so that the foot can output mechanical power without the need for heavy muscles within the foot itself. This thesis advances the understanding of structure-function relationships in the human foot and impacts the fields of evolutionary biology, podiatry and robotics. The renewed understanding of the windlass mechanism, taken together with other studies that compare feet across many primate species, suggests that the power transmission function of the windlass is important for walking, and could have emerged well before the longitudinal arch evolved in humans. Future clinical studies have to consider the transverse arch in evaluating foot function and may find that to be a potential target for the design of foot reconstructive surgeries, design of orthotic implants, and evaluation and classification of flatfoot disorders. Finally, the mechanical foot mimics that were developed may inspire the design of lightweight robotic and prosthetic feet with tunable stiffness properties that exploit the curvature induced stiffening of the human foot

Renewing Race Street: a Mobility Analysis

This study evaluated a proposed design for Race Street between 5th and 9th Street, and a design was developed to improve safety, accessibility, and aesthetics. Between 6th and 8th Street, the design would reduce the north and south crossing distance and change the road to a three travel lane configuration; it would also add protected bicycle facilities, plantings, and pedestrian amenities. These improvements would improve access for people walking, biking, and driving and improve the aesthetics of one of Philadelphia's most visited tourist areas. It would better link the surrounding neighborhoods and amenities together, which include Chinatown, Old City, Independence mall, and Franklin Square. The design would have minimal impact on traffic operations while creating a significantly safer traffic environment

Designing an International Friendship Model For Children

In 2006 this writer traveled to Windhoek, Namibia to take the course Walking the Truth; Culture, Gender and HIV/AID,S in Sub-Saharan Africa. As part of that class each student was assigned to work with an organization or individual whose mission was working with HIV/AIDS patients or there families. It was from this experience that the project was born. The purpose of this project is to design a friendship model that links children of middle school age from different cultures and different nations together through letter writing