Climbing and Walking Robots

With the advancement of technology, new exciting approaches enable us to render mobile robotic systems more versatile, robust and cost-efficient. Some researchers combine climbing and walking techniques with a modular approach, a reconfigurable approach, or a swarm approach to realize novel prototypes as flexible mobile robotic platforms featuring all necessary locomotion capabilities. The purpose of this book is to provide an overview of the latest wide-range achievements in climbing and walking robotic technology to researchers, scientists, and engineers throughout the world. Different aspects including control simulation, locomotion realization, methodology, and system integration are presented from the scientific and from the technical point of view. This book consists of two main parts, one dealing with walking robots, the second with climbing robots. The content is also grouped by theoretical research and applicative realization. Every chapter offers a considerable amount of interesting and useful information

Robust muscle synergies for postural control

The musculoskeletal structure of the human and animal body provides multiple solutions for performing any single motor behavior. The long-term goal of the work presented here is to determine the neuromechanical strategies used by the nervous system to appropriately coordinate muscles in order to achieve the performance of daily motor tasks. The overall hypothesis is that the nervous system simplifies muscle coordination by the flexible activation of muscle synergies, defined as a group of muscles activated as a unit, that perform task-level biomechanical functions. To test this hypothesis we investigated whether muscle synergies can be robustly used as building blocks for constructing the spatiotemporal muscle coordination patterns in human and feline postural control under a variety of biomechanical contexts. We demonstrated the generality and robustness of muscle synergies as a simplification strategy for both human and animal postural control. A few robust muscle synergies were able to reproduce the spatial and temporal variability in human and cat postural responses, regardless of stance configuration and perturbation type. In addition inter-trial variability in human postural responses was also accounted for by these muscle synergies. Finally, the activation of each muscle synergy in cat produced a specific stabilizing force vector, suggesting that muscle synergies control task-level variables. The identified muscle synergies may represent general modules of motor output underlying muscle coordination in posture that can be activated in different sensory contexts to achieve different postural goals. Therefore muscle synergies represents a simplifying mechanism for muscle coordination in natural behaviors not only because it is a strategy for reducing the number of variables to be controlled, but because it represents a mechanism for simply controlling multi-segmental task-level variables.Ph.D.Committee Chair: Ting, Lena H.; Committee Member: Chang, Young-Hui; Committee Member: Lee, Robert H.; Committee Member: Nichols, T. Richard; Committee Member: Wolf, Steve L

Reversible silencing of spinal neurons unmasks a left-right coordination continuum.

This dissertation is focused on dissecting the functional role of two anatomically-defined pathways in the adult rat spinal cord. A TetOn dual virus system was used to selectively and reversibly induce enhanced tetanus neurotoxin expression in L2 neurons that project to L5 (L2-L5) or C6 (long ascending propriospinal neurons, LAPNs). Results focus on the changes observed during overground locomotion. The dissertation is divided into four chapters. Chapter One is a focused introduction to locomotion, including its broad description, the central mechanisms of its expression, how genetic-based approaches defined these mechanisms, and the limitations in these approaches. It concludes with details of the silencing paradigm used here and a summary of the main findings. Chapter Two describes the functional consequences of silencing L2-L5 interneurons. The focus is on selective disruption of hindlimb coordination during overground locomotion, revealing a continuum from walk to hop. These changes are independent of speed, step frequency, and other spatiotemporal features of gait. Left-right alternation was restored during swimming and stereotypic exploration, suggesting a task-specific role. Silencing L2-L5 interneurons partially uncoupled the hindlimbs, allowing spontaneous shifts in coordination on a step-by-step basis. It is proposed this pathway distributes temporal information for left-right hindlimb alternation, securing effective coordination in a context-dependent manner. Chapter Three focuses on the consequences of silencing LAPNs.Three patterns of interlimb coupling are disrupted: left-right forelimb, left-right hindlimb, and contralateral hindlimb-forelimb coordination. Observed again was a context-dependent continuum from walk-to-hop, irrespective of step frequency, speed, and the salient features that define locomotion. However, instead of spontaneous shifts in coordination as observed from L2-L5 interneuron silencing, the breadth of coupling patterns expressed were maintained on a step-by-step basis. It is proposed that this ascending, inter-enlargement pathway distributes temporal information required for left-right alternation at the shoulder and pelvic girdles in a context-dependent manner. Collectively, these data suggest that L2-L5 interneurons and LAPNs are key pathways that distribute left-right patterning information throughout the neuraxis. The functional role(s) of these pathways are exquisitely gated to the context at hand, suggesting that the locomotor circuitry undergoes functional reorganization thereby endowing or masking the silencing-induced disruptions to interlimb coordination

The influence of conformation and gait of the hind limb of the aetiology of cranial cruciate ligament rupture in Rottweilers and Racing Greyhounds

The thesis investigates the hypothesis that the conformation and gait of the hind limb of certain large breeds of dog predisposes to rupture of the cranial cruciate ligament. It is divided into three parts.The first part studies the breed incidence of cranial cruciate ligament rupture in dogs. The second compares the gait and conformation of the hind limb, with particular attention to the stifle joint, in two large breeds of dog, the Rottweiler, in which cruciate damage is common, and the Racing Greyhound, in which it is rare. The third part compares the biomechanical properties of the cranial cruciate ligament and osseous geometry of the tibial plateau in the two breeds.A survey of 72 general practices and 4 veterinary school case records showed a high incidence of cranial cruciate ligament rupture in the Rottweiler relative to its popularity in the general dog population and a lower mean age at the onset of clinical signs compared to all the other breeds affected. Cruciate ligament damage was rarely reported in the Racing Greyhound.Conformation and kinematic gait analysis of 28 Rottweilers and 28 Racing Greyhounds was done with a high speed cinecamera, recording at 50 frames per second, and a microcomputer-based gait analysis system. Frame by frame analysis of the cinefilm showed that the hind limb joints of the Rottweiler exhibited statistically significantly greater ranges of angular motion during the walk and trot compared to the Racing Greyhound. The stifle joint was more extended in the Rottweiler at the in commencement of weight-bearing and the stride length was greater, which together, lead to a tendency to overextend the stifle joint stressing the cranial cruciate ligament.Biomechanical testing of cadaver stifles in 13 Rottweilers and 15 Racing Greyhounds, at the flexion angles determined from the gait analysis, examined the stability of the joints and the material and structural properties of the cranial cruciate ligaments and their bony attachments when loaded in tension. The geometry of the tibial plateau was also investigated. The stifle joints became less stable with increasing joint flexion, the Rottweiler joint being consistently more lax than the Racing Greyhound. This may explain the tendency of the Rottweiler stifle joint to extend more fully than the Racing Greyhound, which is recognised as one mechanism of cranial cruciate ligament rupture. In extension, the tensile strength of the Racing Greyhound cranial cruciate ligament was statistically significantly greater than the Rottweiler, although the strength of the latter increased with increasing joint flexion. The contact angle between the femoral condyles and the tibial plateau changed as the joint was flexed, more so in the Rottweiler where there was a greater backward slope of the plateau.The conformation and gait of the Rottweiler hind limb does influence cranial cruciate ligament damage. The normal Rottweiler stifle joint is more extended than the Racing Greyhound at foot placement when the cranial cruciate ligament is weaker. As the joint flexes, the ligament is stronger but the greater backward slope of the tibial plateau contact point results in a greater force tending to move the tibia forward relative to the femur which must be counteracted by the cranial cruciate ligament. Therefore as the Rottweiler stifle joint flexes from full extension, the ligament and its attachments become biomechanically stronger but the load on the cranial cruciate ligament becomes greater

Humanoid Robots

For many years, the human being has been trying, in all ways, to recreate the complex mechanisms that form the human body. Such task is extremely complicated and the results are not totally satisfactory. However, with increasing technological advances based on theoretical and experimental researches, man gets, in a way, to copy or to imitate some systems of the human body. These researches not only intended to create humanoid robots, great part of them constituting autonomous systems, but also, in some way, to offer a higher knowledge of the systems that form the human body, objectifying possible applications in the technology of rehabilitation of human beings, gathering in a whole studies related not only to Robotics, but also to Biomechanics, Biomimmetics, Cybernetics, among other areas. This book presents a series of researches inspired by this ideal, carried through by various researchers worldwide, looking for to analyze and to discuss diverse subjects related to humanoid robots. The presented contributions explore aspects about robotic hands, learning, language, vision and locomotion

Evaluating footwear “in the wild”: Examining wrap and lace trail shoe closures during trail running

Trail running participation has grown over the last two decades. As a result, there have been an increasing number of studies examining the sport. Despite these increases, there is a lack of understanding regarding the effects of footwear on trail running biomechanics in ecologically valid conditions. The purpose of our study was to evaluate how a Wrap vs. Lace closure (on the same shoe) impacts running biomechanics on a trail. Thirty subjects ran a trail loop in each shoe while wearing a global positioning system (GPS) watch, heart rate monitor, inertial measurement units (IMUs), and plantar pressure insoles. The Wrap closure reduced peak foot eversion velocity (measured via IMU), which has been associated with fit. The Wrap closure also increased heel contact area, which is also associated with fit. This increase may be associated with the subjective preference for the Wrap. Lastly, runners had a small but significant increase in running speed in the Wrap shoe with no differences in heart rate nor subjective exertion. In total, the Wrap closure fit better than the Lace closure on a variety of terrain. This study demonstrates the feasibility of detecting meaningful biomechanical differences between footwear features in the wild using statistical tools and study design. Evaluating footwear in ecologically valid environments often creates additional variance in the data. This variance should not be treated as noise; instead, it is critical to capture this additional variance and challenges of ecologically valid terrain if we hope to use biomechanics to impact the development of new products

Somatosensory stimulation to improve lower-limb recovery after stroke

Introduction Increasing lower-limb sensation could improve walking post-stroke but evidence for this is limited. This thesis reports: 1) Review of published literature on somatosensory stimulation of the foot to enhance lower-limb function post-stroke. 2) Development of standardised intervention protocols for testing in a feasibility trial. 3) Feasibility trial of somatosensory stimulation interventions combined with functional activity. Methods 1) Systematic review with narrative synthesis of somatosensory stimulation to the foot to improve balance and gait post-stroke. 2) Modified Nominal Group Technique with experienced therapists, informed by literature, to develop and seek consensus on three standardised therapy protocols. a) lower-limb mobilization and tactile stimulation (MTS) b) textured insole wearing (TI) c) task-specific gait training (TSGT) 3) Mixed-methods, single-blind feasibility study explored: recruitment, participant characteristics, attrition, intervention and outcome measures acceptability (responses, feasibility, costs), sample size requirements, and participants’ experiences. Adults 42–112 days post-stroke were randomized to either TIs+TSGT or MTS+TSGT. Lower-limb sensorimotor and functional outcomes were measured pre-randomization, post-intervention, and one-month later. Participants’ experiences and acceptability of interventions and outcomes were explored in focus groups, with qualitative data analysed thematically. Quantitative feasibility outcomes were analysed using descriptive statistics, and within-group changes calculated. Results 1) Seventeen trials included in the review confirmed that evidence for somatosensory stimulation to improve lower-limb function post-stroke is limited. 2) Validated trial intervention protocols for MTS, TIs and TSGT were developed, with consensus. 3) Thirty-four stroke survivors were recruited and completed the trial, with acceptable recruitment (48.57%) and attrition (5.88%) rates. Feasibility of outcomes, costs, delivery and acceptability of interventions and outcome measures were confirmed. Potential response to treatment was noted. Conclusion Somatosensory stimulation of the foot post-stroke warrants investigation. Feasibility of a larger trial of somatosensory stimulation interventions was confirmed. Participant characteristics, response over time, and variance of outcome measures will inform a future larger trial