Brachiation on a Ladder with Irregular Intervals

We have previously developed a brachiation controller that allows a two degree of freedom robot to swing from handhold to handhold on a horizontal ladder with evenly space rungs as well as swing up from a suspended posture using a target dynamics controller. In this paper, we extend this class of algorithms to handle the much more natural problem of locomotion over irregularly spaced handholds. Numerical simulations and laboratory experiments illustrate the effectiveness of this generalization

A Hybrid Swing up Controller for a Two-link Brachiating Robot

In this paper, we report on a hybrid scheme for regulating the swing up behavior of a two degree of freedom brachiating robot. In this controller, a previous target dynamics controller and a mechanical energy regulator are combined. The proposed controller guarantees the boundedness of the total energy of the system. Simulations suggest that this hybrid controller achieves much better regulation of the desired swing motion than the target dynamics method by itself

Passive dynamic swing locomotion for a 6dof coplanar articulated chain

Ingeniero (a) ElectrónicoPregrad

Stabilization Control for the Giant Swing Motion of the Horizontal Bar Gymnastic Robot Using Delayed Feedback Control

Open-loop dynamic characteristics of an underactuated system with nonholonomic constraints, such as a horizontal bar gymnastic robot, show the chaotic nature due to its nonlinearity. This chapter deals with the stabilization problems of periodic motions for the giant swing motion of gymnastic robot using chaos control methods. In order to make an extension of the chaos control method and apply it to a new practical use, some stabilization control strategies were proposed, which were, based on the idea of delayed feedback control (DFC), devised to stabilize the periodic motions embedded in the movements of the gymnastic robot. Moreover, its validity has been investigated by numerical simulations. First, a method named as prediction-based DFC was proposed for a two-link gymnastic robot using a Poincar section. Meanwhile, a way to calculate analytically the error transfer matrix and the input matrix that are necessary for discretization was investigated. Second, an improved DFC method, multiprediction delayed feedback control, using a periodic gain, was extended to a four-link gymnastic robot. A set of plural Poincare maps were defined with regard to the original continuous-time system as a T-periodic discrete-time system. Finally, some simulation results showed the effectiveness of the proposed methods

Robotic device for the inspection of steel bridge structures

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009.Includes bibliographical references (p. 83-84).The aging of America's steel bridges presents many challenges. Undetected cracks and corrosion can eventually lead to catastrophic failure. Due to the difficulties with inspecting existing bridges the use of mobile robots for steel bridge inspection has become an important area of research. This thesis describes the analysis, design, and implementation of a new approach to steel bridge inspection robots using tilting feet equipped with permanent magnets. This robot, titled "Mag-Feet", is capable of adhering to steel surfaces and can move along steel surfaces using a combination of three distinct gait modes. These three gait modes allow the robot to "Moonwalk" along horizontal surfaces, "Shuffle" up inclined surfaces, and "Swing" over small obstacles. The "Swing" motions present their own set of interesting challenges. Since the robot can only adhere to the surface using finite (and relatively small) magnetic forces, it may fall due to the reaction forces caused by the swing- up motion. To prevent failure modes, an optimal swing-up trajectory was designed so that the maximum reaction force during the trajectory was minimized. The trajectories were parameterized using sigmoids and were determined by solving the dynamic equations as a 2 point boundary value problem. Finally, a proof of concept prototype was constructed and was used to experimentally evaluate the design. These experiments illustrate the promise of the design and control approaches that were formulated.by Anirban Mazumdar.S.M

A multifactorial approach to improving captive primate welfare and enclosure usage

This thesis examines factors affecting the welfare of captive primates from a multi- factorial perspective: positional and non-positional behaviour, anatomical adaptations and enclosure usage. Past studies have shown that the provision of naturalistic environments for primates reduces stereotypical behaviours, decreases inactivity (Honess and Marin 2005; Zaragoza et al. 2011), and encourages species- typical positional behaviour repertoires (Jensvold et al. 2001). This suggests that encouraging species-typical behaviour improves captive primate welfare. It was found that reduced occurrence of stereotypical behaviour was associated with enrichment encouraging tool-use, a high fibre diet, and increased social behaviour. Compared to wild gorillas, captive gorillas adopted similar feeding and resting postures but performed substantially less vertical climbing, likely arising from differences in habitat structure and food distribution. It was found that the genus Gorilla has a strong preference for <20cm diameter and vertical/angled supports, but equally, gorillas have to some extent retained locomotor plasticity as suggested by Myatt et al. (2011) and Neufuss et al. (2014). Thus, from construction of a 3D musculoskeletal model of a hindlimb, it was found that bipedalism was associated with higher moment arms and torque around the hip, knee and ankle (except for extensor torque), than vertical climbing. This indicates that in terms of moment arms and torque, the ability to walk bipedally is not restricted by musculoskeletal adaptations to vertical climbing. It was also found that the gorilla foot had interossei that attached to distal phalanges, which may be important for fine flexion movements for grasping/manipulation of objects. These findings stress the importance of taking into account locomotor restrictions and plasticity when encouraging species-typical behaviour, which has not previously been emphasized. Further, accurate quantification of support availability and preference for enclosure design and positional behaviour studies has not been achieved before. Thus a novel method of studying enclosure usage was developed, via construction and analysis of a computer-aided design model of an enclosure. Besides successful accurate quantification of support preference and availability, the model permitted identification of specific favoured supports/areas and behaviour trends

The evolution of hominoid ecomorphology studies of locomotor behaviour and anatomy in human and nonhuman apes

An animal’s locomotor abilities facilitate its interactions with the surrounding environment. Extant hominoids (apes) have evolved diverse ranges of locomotor strategies which allow them to exploit terrestrial and arboreal habitats despite their large body size. However, hominins (modern humans and their ancestors) are traditionally defined by their restriction to upright, bipedal posture and locomotion. Reconstructions of locomotor capacity in fossil hominoids allow investigation of the evolution of extant ape locomotion; yet these reconstructions rely on detailed understanding of the relationships between morphology, locomotor behaviour and the environment in extant apes. This thesis explores variation in locomotor behaviour and skeletal morphology among extant apes in order to shed light on these relationships. Studies of chimpanzees, gorillas and modern humans reveal considerable mechanical variation in gait, and demonstrate the importance of considering environmental context in ape locomotion. Anatomical studies find reduced reliability of inferring locomotor capacity in fossil hominoids due to significant variation among extant apes in skeletal predictors of habitual bipedality and estimations of joint range of motion. These studies highlight the importance of behavioural flexibility in determining hominoid locomotor capacity, and suggest that fossil hominoids were less constrained in their locomotor repertoires than previous reconstructions imply

Injury and Skeletal Biomechanics

This book covers many aspects of Injury and Skeletal Biomechanics. As the title represents, the aspects of force, motion, kinetics, kinematics, deformation, stress and strain are examined in a range of topics such as human muscles and skeleton, gait, injury and risk assessment under given situations. Topics range from image processing to articular cartilage biomechanical behavior, gait behavior under different scenarios, and training, to musculoskeletal and injury biomechanics modeling and risk assessment to motion preservation. This book, together with "Human Musculoskeletal Biomechanics", is available for free download to students and instructors who may find it suitable to develop new graduate level courses and undergraduate teaching in biomechanics

Bio-Inspired Robotics

Modern robotic technologies have enabled robots to operate in a variety of unstructured and dynamically-changing environments, in addition to traditional structured environments. Robots have, thus, become an important element in our everyday lives. One key approach to develop such intelligent and autonomous robots is to draw inspiration from biological systems. Biological structure, mechanisms, and underlying principles have the potential to provide new ideas to support the improvement of conventional robotic designs and control. Such biological principles usually originate from animal or even plant models, for robots, which can sense, think, walk, swim, crawl, jump or even fly. Thus, it is believed that these bio-inspired methods are becoming increasingly important in the face of complex applications. Bio-inspired robotics is leading to the study of innovative structures and computing with sensory–motor coordination and learning to achieve intelligence, flexibility, stability, and adaptation for emergent robotic applications, such as manipulation, learning, and control. This Special Issue invites original papers of innovative ideas and concepts, new discoveries and improvements, and novel applications and business models relevant to the selected topics of ``Bio-Inspired Robotics''. Bio-Inspired Robotics is a broad topic and an ongoing expanding field. This Special Issue collates 30 papers that address some of the important challenges and opportunities in this broad and expanding field

Taxonomic Tapestries: The Threads of Evolutionary, Behavioural and Conservation Research

This volume explores the complexity, diversity and interwoven nature of taxonomic pursuits within the context of explorations of humans and related species. It also pays tribute to Professor Colin Groves, whose work has had an enormous impact on this field. Recent research into that somewhat unique species we call humankind, through the theoretical and conceptual approaches afforded by the discipline of biological anthropology, is showcased. The focus is on the evolution of the human species, the behaviour of primates and other species, and how humans affect the distribution and abundance of other species through anthropogenic impact. Weaving together these three key themes, through the considerable influence of Colin Groves, provides glimpses of how changes in taxonomic theory and methodology, including our fluctuating understanding of speciation, have recrafted the way in which we view animal behaviour, human evolution and conservation studies