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

An Overview of Compensatory Pronation at the Subtalar Joint and Orthotic Correction

Excessive compensatory pronation at the subtalar joint is a common foot disorder that affects a large population of people. It is a disorder that stems from a wide variety of causes including both congenital and acquired as well as intrinsic and extrinsic factors. Excessive compensatory pronation is also the cause of many other disorders which may affect not only the foot but other joints including the knee, hip, and back. The scope of this study will focus on acquired pronation and its causes as well as the proper orthotic choice and prescription to best treat the problem. This literature review will discuss the anatomy and biomechanics of the foot, paying particular attention to the subtalar joint as compensatory pronation usually occurs at this joint. It will also discuss various acquired causes of subtalar joint pronation. This review will provide information on material characteristics and patient characteristics that must be considered in order to prescribe the correct orthotic. Studies discussing the effectiveness of treating excessive pronation with orthotics will also be presented

Neuromuscular Control Strategy during Object Transport while Walking: Adaptive Integration of Upper and Lower Limb Movements

When carrying an object while walking, a significant challenge for the central nervous system (CNS) is to preserve the object’s stability against the inter-segmental interaction torques and ground reaction forces. Studies documented several strategies used by the CNS: modulation of grip force (GF), alterations in upper limb kinematics, and gait adaptations. However, the question of how the CNS organizes the multi-segmental joint and muscle coordination patterns to deal with gait-induced perturbations remains poorly understood. This dissertation aimed to explore the neuromuscular control strategy utilized by the CNS to transport an object during walking successfully. Study 1 examined the inter-limb coordination patterns of the upper limbs when carrying a cylinder-shaped object while walking on a treadmill. It was predicted that transporting an object in one hand would affect the movement pattern of the contralateral arm to maintain the overall angular momentum. The results showed that transporting an object caused a decreased anti-phase coordination, but it did not induce significant kinematic and muscle activation changes in the unconstrained arm. Study 2 examined muscle synergy patterns for upper limb damping behavior by using non-negative matrix factorization (NNMF) method. Four synergies were identified, showing a proximal-to-distal pattern of activation preceding heel contacts. Study 3 examined the effect of different precision demands (carrying a cup with or without a ball) and altered visual information (looking forward vs. looking at an object) on the upper limb damping behavior and muscle synergies. Increasing precision demand induced stronger damping behavior and increased the electromyography (EMG) activation of wrist/hand flexors and extensors. The NNMF results replicated Study 2 in that the stabilization of proximal joints occurred before the distal joints. The results indicated that the damping incorporates tonic and phasic muscle activation to ensure object stabilization. Overall, three experiments showed that the CNS adopts a similar synergy pattern regardless of task constraint or altered gaze direction while modulating the amount of muscle activation for object stabilization. Kinematic changes can differ depending on the different levels of constraint, as shown in the smaller movement amplitude of the shoulder joint in the transverse plane during the task with higher precision demand

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

Nonprehensile Dynamic Manipulation: A Survey

Nonprehensile dynamic manipulation can be reason- ably considered as the most complex manipulation task. It might be argued that such a task is still rather far from being fully solved and applied in robotics. This survey tries to collect the results reached so far by the research community about planning and control in the nonprehensile dynamic manipulation domain. A discussion about current open issues is addressed as well

Bio-inspired soft robotic systems: Exploiting environmental interactions using embodied mechanics and sensory coordination

Despite the widespread development of highly intelligent robotic systems exhibiting great precision, reliability, and dexterity, robots remain incapable of performing basic manipulation tasks that humans take for granted. Manipulation in unstructured environments continues to be acknowledged as a significant challenge. Soft robotics, the use of less rigid materials in robots, has been proposed as one means of addressing these limitations. The technique enables more compliant interactions with the environment, allowing for increasingly adaptive behaviours better suited to more human-centric applications. Embodied intelligence is a biologically inspired concept in which intelligence is a function of the entire system, not only the controller or `brain'. This thesis focuses on the use of embodied intelligence for the development of soft robots, with a particular focus on how it can aid both perception and adaptability. Two main hypotheses are raised: first, that the mechanical design and fabrication of soft-rigid hybrid robots can enable increasingly environmentally adaptive behaviours, and second, that sensing materials and morphology can provide intelligence that assists perception through embodiment. A number of approaches and frameworks for the design and development of embodied systems are presented that address these hypotheses. It is shown how embodiment in soft sensor morphology can be used to perform localised processing and thereby distribute the intelligence over the body of a system. Specifically in soft robots, sensor morphology utilises the directional deformations created by interactions with the environment to aid in perception. Building on and formalising these ideas, a number of morphology-based frameworks are proposed for detecting different stimuli. The multifaceted role of materials in soft robots is demonstrated through the development of materials capable of both sensing and changes in material property. Such materials provide additional functionality beyond their integral scaffolding and static mechanical characteristics. In particular, an integrated material has been created exhibiting both sensing capabilities and also variable stiffness and `tack’ force, thereby enabling complex single-point grasping. To maximise the intelligence that can be gained through embodiment, a design approach to soft robots, `soft-rigid hybrid' design is introduced. This approach exploits passive behaviours and body dynamics to provide environmentally adaptive behaviours and sensing. It is leveraged by multi-material 3D printing techniques and novel approaches and frameworks for designing mechanical structures. The findings in this thesis demonstrate that an embodied approach to soft robotics provides capabilities and behaviours that are not currently otherwise achievable. Utilising the concept of `embodiment' results in softer robots with an embodied intelligence that aids perception and adaptive behaviours, and has the potential to bring the physical abilities of robots one step closer to those of animals and humans.EPSR

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

A systems-level perspective of the flexion-relaxation phenomenon in the lumbar spine

Standard anatomic classifications such as trunk , lower limbs , upper limbs can be misleading regarding the functional role and influence that the tissues in these body regions may play in adjacent body regions. In particular, much of the spine biomechanics literature has considered the lumbar spine in isolation, neglecting to account for the influence of the tissues of the lower extremities (muscles, ligaments and fascia) on the performance of the lumbar region of the torso. Some previous literature supports a systems level (i.e., trunk, pelvis and lower extremities) approach for better understanding of trunk stability during flexion-extension motions. The current study presents a new musculoskeletal model of the active spinal stability system that includes the local system (e.g., multifidus muscles) and global system (e.g., lateral erector spinae, rectus abdominis muscles etc.) as proposed by Bergmark (1989), but then adds a super global system that considers the influence of the lower extremity tissues on the responses of the lumbar region. This innovative model was verified throughout in vivo experiments involving human subjects that included three different physical exertion tasks that stressed the low back and the lower extremities in different ways to explore these important interactions. The empirical work in this dissertation focused on gathering data from the local, global and super global biomechanical systems before and after three 10 minute exercise protocols and then during a 40 minute recovery session. Twelve participants performed three separate experiments (three protocols) on different days: Protocol A- alternately perform 25 seconds of full trunk flexion and 5 seconds upright, relaxed posture; Protocol B- alternately perform 25 seconds of isometric exertion in a 45 degree trunk flexion posture and 5 seconds upright, relaxed posture; and Protocol C- consecutively perform 25 seconds of full trunk flexion followed by 5 seconds of upright, relaxed posture followed by 25 seconds of isometric exertion in a 45 degree trunk flexion posture and 5 seconds upright, relaxed posture. Kinematic and physiological measures were recorded before during after these protocols as well as during the recovery period. In addition, a variable describing the level of fixation of the pelvis was considered to allow for a direct evaluation of the role of the pelvis/lower extremities on the performance of the lumbar region during these exertions: 1) lower extremity restricted stooping posture (pelvis and thigh restriction) and 2) free stooping posture. The data collected in these experimental trials included the peak lumbar flexion angle, the peak hip flexion angle, the peak trunk flexion angle, the EMG-off angle (i.e., flexion-relaxation), and the average normalized integrated electromyography (NIEMG) for the agonist muscles (lumbar extensors (multifidus and iliocostalis)), the antagonist muscles (lumbar flexors (rectus abdominis and external obliques)) and the lower extremity synergistic muscles (gluteus maximus and biceps femoris). The results of in vivo experiments, focused on the role of the pelvis/lower extremities in trunk flexion-extension, showed a 6.4% greater lumbar flexion angle (36y vs. 38.3y), a 10.2% greater (or later) EMG-off angle in multifidus (31.6y vs. 34.8y), and a 8% greater EMG-off angle in the iliocostalis (30.6y vs. 33y) in the restricted stooping posture than in the free stooping posture. Collectively, these results suggest that additional passive moments about the lumbar spine are generated in the restricted stooping posture because of the relative fixation of the pelvis that is seen during the restricted stooping condition. Consistent with these results, 22% greater lower extremity activation (10.5% MVC vs. 8.2% MVC) was observed in the free stooping posture, as compared to the restricted stooping posture. This additional lower extremity muscle activation acts to stabilize the pelvis (the foundation of the spinal column) and generate passive moments in low back through the lumbodorsal fascia. Consequently, the enhanced pelvic stability and passive moments in the low back generated by the lower extremity active system (i.e. the super global system) led to the an 8% lower low back muscle activation level (15.1% MVC vs. 16. 3% MVC) in the free stooping condition. In addition, under the abnormal low back conditions (after protocols), the agonist muscles showed significant increases in both the free stooping posture and the restricted stooping posture (15% in both) to maintain spinal stability, but the synergist only increased in the free stooping (22%, 11.2% MVC vs. 13.7% MVC) (no difference in the restricted stooping posture). To summarize, these results indicate a significant role of the tissues of the larger super global system as a trunk stabilizer by immobilizing the pelvis during trunk flexion-extension motions and increasing the stiffness of the trunk systems by enhancing tension of the lumbodorsal fascia. Regarding the effects of the 10 minute protocols on the biomechanical responses, results showed greater full lumbar flexion and deeper biomechanical equilibrium point between passive tissues and external moment (i.e., EMG-off angles) than the baseline (initial measure) after Protocol A: full lumbar flexion increased 7%; EMG-off angle increased 7.2% in multifidus and increased 7.8% in iliocostalis. In Protocol B the trends in the dependent variables were opposite to those seen in Protocols A: full lumbar flexion angle decreased by 4% and the EMG-off angles decreased by 4.9% in the multifidus and by 6.3% in iliocostalis. Protocol C (the mixed protocol) generated similar, but less pronounced results as compared to Protocol A: full lumbar flexion increased by 3.7%; EMG-off angles increased by 3.7% in multifidus and by 5.9% in iliocostalis. The results of Protocol A and B are consistent with the results of previous studies of these responses and demonstrate important biomechanical effects that need to be considered when modeling the lumbar spine in full or near full-flexion postures. Protocol C was a condition that had not been considered in previous studies and these results indicate that the result of a mixed effort protocol may depend on the relative intensity of the passive vs. the active fatigue. In the current study the passive tissue fatigue appears to have dominated since the results of Protocol C are somewhat similar to those seen in Protocol A. In all three protocols there appears to have been significant compromise of the passive spinal stability system, as the muscle activities in agonist muscles and synergist muscles were significantly increased in all three protocols illustrating an increased need for active control of the lumbar region. In terms of the recovery process, the in vivo experiment, comparing characteristics of the recovery phase in three protocols, showed longer recovery time after the passive tissue elongation protocol (not fully recovered until 40 minutes of rest in all variables) than the muscle fatigue protocol (recovered after 5 minutes of resting in all variables) and the combined protocol (not fully recovered until 40 minutes of resting for the full lumbar flexion angle and the EMG-off angle; fully recovered in agonist muscle activation after 40 minutes of resting; and fully recovered in the synergist muscles after 5 minutes of resting). The results suggest that the slow recovery of the viscoelastic tissues caused by the prolonged stooping of Protocols A and C may lead to periods of spinal instability because of the abnormally lax passive tissues. While not a direct results of this study, these results may indicate an increased risk of injury during this period of passive tissue remodeling. Also, the enhanced activation in the synergist muscles (i.e., super global system) and depression in the antagonist muscles during the recovery session suggest an interaction mechanism between antagonist and synergist which may be planned in skilled motor programs before the initiation of the movement. Meanwhile, contrary to the results of passive tissues elongation protocol, the muscle fatigue protocol showed relatively quick recovery in all responses measures, but higher levels of muscle activity increase immediately after the protocol: Protocol B (agonist: 14.2%; synergist: 12.5%) vs. Protocol A (agonist: 9.2%; synergist: 4.7%) and Protocol C (agonist: 11.5%; synergist: 5.1%)). In all three protocols, the super global system (i.e., synergist) showed a recovery pattern that was quite similar to the agonist muscle response. The results of the theoretical modeling and experimental validation components of the current study indicate that a new musculoskeletal model with a more systems-level perspective is necessary to fully understand the biomechanical response of the lumbar spine during full flexion and near full flexion exertion. This study has filled a void in the literature in that it addresses 1) the role of the super global system (i.e., lower extremity) in both normal and abnormal condition, 2) the effect of combined effect protocol (both laxity of the passive tissues and fatigue of the active tissues), 3) differences in the biomechanical responses as a function of the type of fatigue developed (passive tissue, active tissue, combined passive and active tissue fatigue), and 4) dynamic and variable responses of the chosen biomechanical measures during recovery. The results of this new systems-level biomechanical model can be used to develop a new EMG-assisted model of spinal loading and spinal stability as well as guidelines for designing safer working environments that can lower the risks of musculoskeletal injury to the low back

PREDICTIVE SIMULATION OF HUMAN MOVEMENT AND APPLICATIONS TO ASSISTIVE DEVICE DESIGN AND CONTROL

Predictive simulation based on dynamic optimization using musculoskeletal models is a powerful approach for studying biomechanics of human gait. Predictive simulation can be used for a variety of applications from designing assistive devices to testing theories of motor controls. However, one of the challenges in formulating the predictive dynamic optimization problem is that the cost function, which represents the underlying goal of the walking task (e.g., minimal energy consumption) is generally unknown and is assumed a priori. While different studies used different cost functions, the qualities of the gaits with those cost functions were often not provided. Therefore, this dissertation evaluates and examines different cost function forms for dynamic simulation of human walking. The problem of the walking cost function determination was cast as a bilevel optimization, which was solved using a nested evolutionary approach. The results showed cost functions based on a weighted combination of muscle-based performance criteria (e.g., metabolic cost, muscle fatigue), gait smoothness, and gait stability led to better walking solutions compared to any cost functions only based on muscle performance criteria. Further evaluations of the walking cost functions were done in the simulation cases of human walking augmented with assistive devices such as prosthesis and exoskeleton. The simulations of augmented walking were comparable to the experimental results, which suggests the potential of using the simulation approach to address problems of finding assistive device design and control