bluuebunny/crossref_metadata_2025 huggingface dataset:
The Significance of Computational Modelling in Murine Cardiac Ventricular Cells
Authors: Demir Semahat S.
Published: March 2015

Five decades of histological, electrophysiological, pharmacological and biochemical investigations exist, but relatively little is known regarding the ionic mechanisms underlying the action potential variations in the ventricle associated with healthy and disease conditions. The computational modelling in murine ventricular myocytes can complement our knowledge of the experimental data and provide us with more quantitative descriptions in understanding different conditions related to normal and disease conditions. This paper initially reviews the theoretical modelling for cardiac ventricular action potentials of various species and the related experimental work. It then focuses on the progress of computational modelling of cardiac ventricular cells for normal, diabetic and spontaneously hypertensive rats. Also presented is the recent modelling efforts of the action potential in mouse ventricular cells. The computational insights gained into the ionic mechanisms in rodents will enhance our understanding of the heart and provide us with new knowledge for future studies to treat cardiac diseases in children and adults.
Bionic Ears: Their Development and Future Advances Using Neurotrophins and Inherently Conducting Polymers
Authors: Clark Graeme M. , Wallace Gordon
Published: March 2015

The development of the multiple-channel bionic ear for hearing and speech understanding in profoundly deaf people is the result of integrating biological and physical sciences with engineering. It is the first clinically successful restoration of sensory and brain function, and brings electronic technology into a direct functional relationship with human consciousness. It presently transmits essential place and coarse temporal information for the coding of frequency, but the fine temporal and place excitation of groups of nerve fibres is inadequate for high-fidelity sound. This is required for adequate musical appreciation and hearing in noise. Research has demonstrated that nerve growth factors preserve the peripheral processes of the auditory nerves so that an electrode array placed close to these fibres could produce this fine temporal and spatial coding. The nerve growth factors can be incorporated into inherently conducting polymers that are part of the array so the peripheral processes can be preserved at the same time as they are electrically stimulated.
Control of a Biped Robot by Total Rate of Angular Momentum Using the Task Function Approach
Authors: Rojas-Estrada J. A. , Marot J. , Sardain P. , Bessonnet G.
Published: March 2015

In this work we address the control problem of biped robots by using the task function approach. A problem arrives when one of the feet is in contact with the ground, which presents imperfections. There is then the possibility that the biped robot undergoes a fall. It is difficult to track any trajectory due to the presence of unevenness on the ground. What we propose is to use the task function approach combined with the application of the total rate of angular momentum to obtain a control law for the ankle. By this technique, the tracking becomes more smooth and the balance is assured. The control law proposed allows the upper part of the robot to be controlled independently since only the ankle actuators are concerned. We enounce the formal problem and present some simulations with real parameters of a 21 degrees of freedom biped robot.
Comparison of Fibroblast and Vascular Cell Adhesion to Nano-Structured Poly(lactic-co-glycolic acid) Films
Authors: Miller D. C. , Vance R. J. , Thapa A. , Webster T. J. , Haberstroh K. M.
Published: March 2015

The success of small diameter vascular grafts may be attributed to the ability to accurately mimic the nano-structured topography of extra-cellular matrix components of natural vascular tissue. Using this knowledge, the goal of the present study was to develop synthetic biomaterials that promote vascular cell adhesion and growth, while subsequently limiting fibrous tissue formation. For this purpose, poly(lactic-co-glycolic acid) (PLGA) with increased nanometer surface roughness was created by treating the surfaces of conventional PLGA with NaOH. Cell experiments on these surfaces indicated that nano-structured PLGA enhanced vascular smooth muscle cell adhesion and growth, while decreasing endothelial cell and fibroblast adhesion and growth, compared to their conventional counterparts. These favorable results were attributed to the selective adsorption of vitronectin. In combination, results of the present in vitro study provided evidence that nano-structured surface features have the potential to significantly improve the efficacy of small diameter vascular implants.
Deconjugation of Bile Acids with Immobilized Genetically EngineeredLactobacillus plantarum80(pCBH1)
Authors: Jones M. L. , Martoni C. , Chen H. , Ouyang W. , Metz T. , Prakash S.
Published: March 2015

Bile acids are important to normal human physiology. However, bile acids can be toxic when produced in pathologically high concentrations in hepatobileary and other diseases. This study shows that immobilized genetically engineeredLactobacillus plantarum80 (pCBH1) (LP80 (pCBH1)) can efficiently hydrolyze bile acids and establishes a basis for their use. Results show that immobilized LP80 (pCBH1) is able to effectively break down the conjugated bile acids into glycodeoxycholic acid (GDCA) and taurodeoxycholic acid (TDCA) with bile salt hydrolase (BSH) activities of 0.17 and 0.07 μmol DCA/mg CDW/h, respectively. The deconjugation product, deoxycholic acid (DCA), was diminished by LP80 (pCBH1) within 4 h of initial BSH activity. Thisin-vitrostudy suggests that immobilized genetically engineered bacterial cells have important potential for deconjugation of bile acids for lowering of high levels of bile acids for therapy.
Robot Imitation: Body Schema and Body Percept
Authors: Acosta-Calderon C. A. , Hu H.
Published: March 2015

There are two functional elements used by humans to understand and perform actions. These elements are: the body schema and the body percept. The first one is a representation of the body that contains information of the body's capabilities. The second one is a snapshot of the body and its relation with the environment at a given instant. These elements interact in order to generate, among other abilities, the ability to imitate. This paper presents an approach to robot imitation based on these two functional elements. Our approach is gradually expanded throughout three developmental stages used by humans to refine imitation. Experimental results are presented to support the feasibility of the proposed approach at the current stage for 2D movements and simple manipulation actions.
Biomechanical Modelling of the Upper Limb for Robotics-Based Orthotic Tremor Suppression
Authors: Rocon E. , Ruiz A. F. , Pons J. L.
Published: March 2015

Orthotic management has been proposed as an interesting alternative to current tremor management methods. It is expected that an improvement on manipulative function can be obtained by reducing the tremorous motion associated with some neurological disorders. For this to be possible, a sound modelling of the tremor and the biomechanical characteristics of the upper limb is required. This paper proposes a model for both the tremor motion and the biomechanical parameters of the upper limb. Based on these models and on a prototype of a robotics-based active orthosis two tremor reduction strategies are proposed.
An Optimal Design of Driving Mechanism in a 1 Degree of Freedom (d.o.f.) Anthropomorphic Finger
Authors: Ceccarelli M. , Rodríguez N. E. N. , Carbone G. , Lopez-Cajùn C.
Published: March 2015

Mechanisms can be used in finger design to obtain suitable actuation systems and to give stiff robust behavior in grasping tasks. The design of driving mechanisms for fingers has been attached at LARM in Cassino with the aim to obtain one degree of freedom actuation for an anthropomorphic finger. The dimensional design of a finger-driving mechanism has been formulated as a multi-objective optimization problem by using evaluation criteria for fundamental characteristics regarding with finger motion, grasping equilibrium and force transmission. The feasibility of the herein proposed optimum design procedure for a finger-driving mechanism has been tested by numerical examples that have been also used to enhance a prototype previously built at LARM in Cassino.
Robot Control Using Electromyography (EMG) Signals of the Wrist
Authors: DaSalla C. , Kim J. , Koike Y.
Published: March 2015

The aim of this paper is to design a human–interface system, using EMG signals elicited by various wrist movements, to control a robot. EMG signals are normalized and based on joint torque. A three-layer neural network is used to estimate posture of the wrist and forearm from EMG signals. After training the neural network and obtaining appropriate weights, the subject was able to control the robot in real time using wrist and forearm movements.
A Vision-Based Method for Autonomous Landing of a Rotor-Craft Unmanned Aerial Vehicle
Authors: Yuan Z. , Gong Z. , Chen J. , Wu J.
Published: March 2015

This article introduces a real-time vision-based method for guided autonomous landing of a rotor-craft unmanned aerial vehicle. In the process of designing the pattern of landing target, we have fully considered how to make this easier for simplified identification and calibration. A linear algorithm was also applied using a three-dimensional structure estimation in real time. In addition, multiple-view vision technology is utilized to calibrate intrinsic parameters of camera online, so calibration prior to flight is unnecessary and the focus of camera can be changed freely in flight, thus upgrading the flexibility and practicality of the method.
Effects of Stenting on Blood Flow in a Coronary Artery Network Model
Authors: Raghu R. , Pullan A. , Smith N.
Published: March 2015

The effect of stenting on blood flow is investigated using a model of the coronary artery network. The parameters in a generic non-linear pressure–radius relationship are varied in the stented region to model the increase in stiffness of the vessel due to the presence of the stent. A computationally efficient form of the Navier–Stokes equation is solved using a Lax–Wendroff finite difference method. Pressure, vessel radius and flow velocity are computed along the vessel segments. Results show negative pressure gradients at the ends of the stent and increased velocity through the middle of the stented region. Changes in local flow patterns and vessel wall stresses due to the presence of the stent have been shown to be important in restenosis of vessels. Local and global pressure gradients affect local flow patterns and vessel wall stresses, and therefore may be an important factor associated with restenosis. The model presented in this study can be easily extended to solve flows for stented vessels in a full, anatomically realistic coronary network. The framework to allow for the effects of the deformation of the myocardium on the coronary network is also in place.
Pneumatic Artificial Muscles Based on Biomechanical Characteristics of Human Muscles
Authors: Saga N. , Nagase J. , Saikawa T.
Published: March 2015

This article reports the pneumatic artificial muscles based on biomechanical characteristics of human muscles. A wearable device and a rehabilitation robot that assist a human muscle should have characteristics similar to those of human muscle. In addition, since the wearable device and the rehabilitation robot should be light, an actuator with a high power to weight ratio is needed. At present, the McKibben type is widely used as an artificial muscle, but in fact its physical model is highly nonlinear. Therefore, an artificial muscle actuator has been developed in which high-strength carbon fibres have been built into the silicone tube. However, its contraction rate is smaller than the actual biological muscles. On the other hand, if an artificial muscle that contracts axially is installed in a robot as compactly as the robot hand, big installing space is required. Therefore, an artificial muscle with a high contraction rate and a tendon-driven system as a compact actuator were developed, respectively. In this study, we report on the basic structure and basic characteristics of two types of actuators.
Alternative Paths to Hearing (A Conjecture). Photonic and Tactile Hearing Systems Displaying the Frequency Spectrum of Sound
Authors: Hara E. H.
Published: March 2015

In this article, the hearing process is considered from a system engineering perspective. For those with total hearing loss, a cochlear implant is the only direct remedy. It first acts as a spectrum analyser and then electronically stimulates the neurons in the cochlea with a number of electrodes. Each electrode carries information on the separate frequency bands (i.e., spectrum) of the original sound signal. The neurons then relay the signals in a parallel manner to the section of the brain where sound signals are processed. Photonic and tactile hearing systems displaying the spectrum of sound are proposed as alternative paths to the section of the brain that processes sound. In view of the plasticity of the brain, which can rewire itself, the following conjectures are offered. After a certain period of training, a person without the ability to hear should be able to decipher the patterns of photonic or tactile displays of the sound spectrum and learn to ‘hear’. This is very similar to the case of a blind person learning to ‘read’ by recognizing the patterns created by the series of bumps as their fingers scan the Braille writing. The conjectures are yet to be tested. Designs of photonic and tactile systems displaying the sound spectrum are outlined.
Evaluation of Morphological and Functional Nerve Recovery of Rat Sciatic Nerve with a Hyaff11-Based Nerve Guide
Authors: Jansen K. , Ludwig Y. , van Luyn M. J. A. , Gramsbergen A. A. , Meek M. F.
Published: March 2015

Application of a Hyaff11-based nerve guide was studied in rats. Functional tests were performed to study motor nerve recovery. A withdrawal reflex test was performed to test sensory recovery. Morphology was studied by means of histology on explanted tissue samples. Motor nerve recovery was established within 7 weeks. Hereafter, some behavioral parameters like alternating steps showed an increase in occurence, while others remained stable. Sensory function was observed within the 7 weeks time frame. Nerve tissue had bridged the 10-mm gap within 7 weeks. The average nerve fiber surface area increased significantly in time. In situ degradation of the nerve conduit was fully going on at week 7 and tubes had collapsed by then. At weeks 15 and 21, the knitted tube wall structure was completely surrounded by macrophages and giant cells, and matrix was penetrating the tube wall. We conclude that a Hyaff11-based nerve guide can be used to bridge short peripheral nerve defects in rat. However, adaptations need to be made.
A Quantified Description of the Coupling between the Reaching Direction and Elbow Axis Direction
Authors: Stanišić M. M. , Goehler C. M. , Tomšič M.
Published: March 2015

The human body continues to be an inspiration for the work of a myriad of different fields, both scientific and mathematic. In particular, robotics draws upon the motions and relationships of different human systems in order to reproduce similar mobility while performing different tasks. The human shoulder–arm–elbow complex has been one of the most difficult to exactly replicate. This paper examines the relationship between the motion of the shoulder while positioning the center of the wrist during voluntary arm movements and the resulting orientation of the arm, in particular the direction of the axis passing through the elbow joint. Experimental data is presented that was used to quantify this coupling between the reaching direction of the arm and the elbow axis direction. The results from this paper are two surface-fit equations that can be used to determine the elbow axis direction when given the location of the wrist center. These results are useful when considering the design and control of shoulder–arm–elbow complex models.
The Use of Evolution in a Central Action Selection Model
Authors: Montes-Gonzalez F. , Bautista-Cabrera P. , Escobar-Ruiz V.
Published: March 2015

The use of effective central selection provides flexibility in design by offering modularity and extensibility. In earlier papers we have focused on the development of a simple centralized selection mechanism. Our current goal is to integrate evolutionary methods in the design of non-sequential behaviours and the tuning of specific parameters of the selection model. The foraging behaviour of an animal robot (animat) has been modelled in order to integrate the sensory information from the robot to perform selection that is nearly optimized by the use of genetic algorithms. In this paper we present how selection through optimization finally arranges the pattern of presented behaviours for the foraging task. Hence, the execution of specific parts in a behavioural pattern may be ruled out by the tuning of these parameters. Furthermore, the intensive use of colour segmentation from a colour camera for locating a cylinder sets a burden on the calculations carried out by the genetic algorithm.
Surface Approximation using Growing Self-Organizing Nets and Gradient Information
Authors: Rivera-Rovelo Jorge , Bayro-Corrochano Eduardo
Published: March 2015

In this paper we show how to improve the performance of two self-organizing neural networks used to approximate the shape of a 2D or 3D object by incorporating gradient information in the adaptation stage. The methods are based on the growing versions of the Kohonen's map and the neural gas network. Also, we show that in the adaptation stage the network utilizes efficient transformations, expressed as versors in the conformal geometric algebra framework, which build the shape of the object independent of its position in space (coordinate free). Our algorithms were tested with several images, including medical images (CT and MR images). We include also some examples for the case of 3D surface estimation.
Simple Mathematical and Computational Wear Model for Ultra-High-Molecular-Weight Polyethylene Total Hip Replacements
Authors: Chan K. H. S. , Pearce T. , Blake R. W. , Chow L. , Wu S. , Wong F. , Li J.
Published: March 2015

Ultra-high-molecular-weight polyethylene is an important constituent of hip implants. Surgical revisions are required because of implant loosening and osteolysis (destruction or resorption of bone tissue). We develop a mathematical and a computational model to determine implant life (defined as the time when 20% of the implants operating at a given wear rate is revised) based on wear rates and apply them to the data of Sochart (Clin Orthop Relat Res, 363:135–50, 1999). No significant difference was found between mathematical and computational model predictions (14.8 and 14.7 years, respectively) from the actual value of 15.0 ± 3.9 years (X¯± 2SE; P > 0.05). We find that an increase in cross-linking does not decrease implant life greatly. However, a large decrease in implant life occurs with an increase in surface roughness, cycles per year and body weight or a decrease in contact stress and femoral head radius.
Analysis of Physical Human–Robot Interaction for Motor Learning with Physical Help
Authors: Ikemoto Shuhei , Minato Takashi , Ishiguro Hiroshi
Published: March 2015

In this paper, we investigate physical human–robot interaction (PHRI) as an important extension of traditional HRI research. The aim of this research is to develop a motor learning system that uses physical help from a human helper. We first propose a new control system that takes advantage of inherent joint flexibility. This control system is applied on a new humanoid robot called CB2. In order to clarify the difference between successful and unsuccessful interaction, we conduct an experiment where a human subject has to help the CB2robot in its rising-up motion. We then develop a new measure that demonstrates the difference between smooth and non-smooth physical interactions. An analysis of the experiment’s data, based on the introduced measure, shows significant differences between experts and beginners in human–robot interaction.
The Roles of CPG Phase Modulation and Reflexive Muscular Patterns in Balance Recovery During Walking—A Simulation Study
Authors: Ikemoto Yu , Yu Wenwei
Published: March 2015

Most walking assist systems reported are not available for real world environments where frequent perturbations are caused by slips, uneven terrain, slopes and obstacles. It is evident that humans are able to cope with such perturbations with reflexes that cause unconscious, relatively fixed muscular response patterns to perturbations within a short period of time. In our previous study, we showed that artificial reflexes could improve the perturbation resistance for simulated walkers, though the roles of different reflexive mechanisms were not quantitatively clarified. In this study, we focused on the different roles of reflexive muscle responses and the CPG phase modulation mechanism. By proposing and evaluating two stability criteria through a series of simulation experiments, we revealed different roles for two mechanisms in the simulated walkers. These will not only further increase the possibility of realising artificial reflexes for paralysed individuals, but also bring new insights into the field of motor control.
Mechatronics and Bioinspiration in Actuator Design and Control
Authors: Pons J. L. , Forner-Cordero A. , Rocon E. , Moreno J. C.
Published: March 2015

Actuators are components of motion control systems in which mechatronics plays a crucial role. They can be regarded as a paradigmatic case in which this mechatronic approach is required. Furthermore, actuator technologies can get new sources of inspiration from nature (bioinspiration). Biological systems are the result of an evolutionary process and show excellent levels of performance. In this paper, we analyse the actuator as a bioinspired mechatronic system through analogies between mechatronics and biological actuating mechanisms that include hierarchical control of actuators, switched control of power flow and some transduction principles. Firstly, some biological models are introduced as a source of inspiration for setting up both actuation principles and control technologies. Secondly, a particular actuator technology, the travelling wave ultrasonic motor, is taken to illustrate this approach. Eventually, the last section draws some conclusions and points out future directions.
Adaptive Fuzzy-Lyapunov Controller Using Biologically Inspired Swarm Intelligence
Authors: Carrasco Elizalde Alejandro , Goldsmith Peter
Published: March 2015

The collective behaviour of swarms produces smarter actions than those achieved by a single individual. Colonies of ants, flocks of birds and fish schools are examples of swarms interacting with their environment to achieve a common goal. This cooperative biological intelligence is the inspiration for an adaptive fuzzy controller developed in this paper. Swarm intelligence is used to adjust the parameters of the membership functions used in the adaptive fuzzy controller. The rules of the controller are designed using a computing-with-words approach called Fuzzy-Lyapunov synthesis to improve the stability and robustness of an adaptive fuzzy controller. Computing-with-words provides a powerful tool to manipulate numbers and symbols, like words in a natural language.
Bionics in Engineering Education Considerations, Experiences and Conclusions
Authors: Neurohr Ralf , Dragomirescu Cristian
Published: March 2015

During recent years bionics, a new discipline which is in charge with the transfer of the principles of construction, regulation, interaction and organisation of biology into innovative technical solutions, has attracted significant interest from various industries. Based on this request for bionic expertise in engineering, the faculty for teaching engineering in foreign languages (FILS) at ‘Politehnica’ University of Bucharest started a course in bionics in SS 2007, which was supported by the expertise of the German ‘Bionik-Kompetenz-Netz’, one of the leading organizations in bionics. This is the report on the considerations involved in the course concept, the first experiences with the students' acceptance, some conclusions and future perspectives for extending bionics activities at ‘Politehnica’. Finally, within the last section, the evaluation of a questionnaire, filled in by the students at the end of the course, will be presented. In order to avoid any confusion, considering overlapping or mixing up with other bio-disciplines related to technology, the paper starts with a short introduction, explaining the principles of bionics and providing a clear definition of the field.
Towards a Methodical Approach to Implement Biomimetic Paradigms in the Design of Robotic Systems for Space Applications
Authors: Menon C. , Lan N. , Sameoto D.
Published: March 2015

Biomimetic design is considered a promising source of novel solutions to problems in space engineering and robotics in particular. With the maturing of this discipline, however, a need is identified: a more systematic approach to its application to reduce the element of chance in the design of biomimetic systems. A methodology is proposed to address this concern and provide a basis for further development of biomimetic design procedures. The application of this process is illustrated through case studies of ongoing biomimetics research with relevance to space robotics in the form of climbing robots utilising synthetic dry adhesives.
Design of a 2-Finger Hand Exoskeleton for Finger Stiffness Measurements
Authors: Fiorilla Angelo Emanuele , Tsagarakis Nikos G. , Nori Francesco , Sandini Giulio
Published: March 2015

Recent studies of human arm movements have suggested that the control of stiffness may be important both for maintaining stability and for achieving differences in movement accuracy. Several studies in the robotic field demonstrated that grasp stiffness is useful for modelling and controlling manipulators but, even though it is accredited that having models of the human finger impedance would be very desirable for the control of anthropomorphous robot's hands, relatively few studies have focused on finger and hand stiffness. To allow the measurement of such entities at the finger level, an appropriate device capable of applying fast force transients while at the same time be able to monitor the finger movements is required. The work presented in this paper is a very detailed report about the design of a new hand exoskeleton system that will be used in our future works to investigate the finger stiffness range in different grasping postures and conditions.
A Study on the Bandwidth Characteristics of Pleated Pneumatic Artificial Muscles
Authors: Versluys Rino , Deckers Kristel , Van Damme Michaël , Van Ham Ronald , Steenackers Gunther , Guillaume Patrick , Lefeber Dirk
Published: March 2015

Pleated pneumatic artificial muscles have interesting properties that can be of considerable significance in robotics and automation. With a view to the potential use of pleated pneumatic artificial muscles as actuators for a fatigue test bench (high forces and small displacements), the bandwidth characteristics of a muscle-valve system were investigated. Bandwidth is commonly used for linear systems, as the Bode plot is independent of the amplitude of the input signal. However, due to the non-linear behaviour of pleated pneumatic artificial muscles, the system's gain becomes dependent on the amplitude of the input sine wave. As a result, only one Bode plot is insufficient to clearly describe or identify a non-linear system. In this study, the bandwidth of a muscle-valve system was assessed from two perspectives: a varying amplitude and a varying offset of the input sine wave. A brief introduction to pneumatic artificial muscles is given. The concept of pleated pneumatic artificial muscles is explained. Furthermore, the different test methods and experimental results are presented.
A Force-Feedback Exoskeleton for Upper-Limb Rehabilitation in Virtual Reality
Authors: Frisoli Antonio , Salsedo Fabio , Bergamasco Massimo , Rossi Bruno , Carboncini Maria C.
Published: March 2015

This paper presents the design and the clinical validation of an upper-limb force-feedback exoskeleton, the L-EXOS, for robotic-assisted rehabilitation in virtual reality (VR). The L-EXOS is a five degrees of freedom exoskeleton with a wearable structure and anthropomorphic workspace that can cover the full range of motion of human arm. A specific VR application focused on the reaching task was developed and evaluated on a group of eight post-stroke patients, to assess the efficacy of the system for the rehabilitation of upper limb. The evaluation showed a significant reduction of the performance error in the reaching task (pairedt-test, p < 0.02)
Design and Control of a Lower Limb Exoskeleton for Robot-Assisted Gait Training
Authors: Beyl Pieter , Van Damme Michaël , Van Ham Ronald , Vanderborght Bram , Lefeber Dirk
Published: March 2015

Robot-assisted rehabilitation of gait still faces many challenges, one of which is improving physical human-robot interaction. The use of pleated pneumatic artificial muscles to power a step rehabilitation robot has the potential to meet this challenge. This paper reports on the development of a gait rehabilitation exoskeleton with a knee joint powered by pleated pneumatic artificial muscles. It is intended as a platform for the evaluation of design and control concepts in view of improved physical human-robot interaction. The design was focused on the optimal dimensioning of the actuator configuration. Safety being the most important prerequisite, a proxy-based sliding mode controller (PSMC) was implemented as it combines accurate tracking during normal operation with a smooth, slow and safe recovery from large position errors. Treadmill walking experiments of a healthy subject wearing the powered exoskeleton show the potential of PSMC as a safe robot-in-charge control strategy for robot-assisted gait training.
Exoskeleton-Based Robotic Platform Applied in Biomechanical Modelling of the Human Upper Limb
Authors: Ruiz Andres F. , Rocon Eduardo , Forner-Cordero Arturo
Published: March 2015

One of the approaches to study the human motor system, and specifically the motor strategies implied during postural tasks of the upper limbs, is to manipulate the mechanical conditions of each joint of the upper limbs independently. At the same time, it is essential to pick up biomechanical signals and bio-potentials generated while the human motor system adapts to the new condition. The aim of this paper is two-fold: first, to describe the design, development and validation of an experimental platform designed to modify or perturb the mechanics of human movement, and simultaneously acquire, process, display and quantify bioelectric and biomechanical signals; second, to characterise the dynamics of the elbow joint during postural control. A main goal of the study was to determine the feasibility of estimating human elbow joint dynamics using EMG-data during maintained posture. In particular, the experimental robotic platform provides data to correlate electromyographic (EMG) activity, kinetics and kinematics information from the upper limb motion. The platform aims consists of an upper limb powered exoskeleton, an EMG acquisition module, a control unit and a software system. Important concerns of the platform such as dependability and safety were addressed in the development. The platform was evaluated with 4 subjects to identify, using system identification methods, the human joint dynamics, i.e. visco-elasticity. Results obtained in simulations and experimental phase are introduced.
Freeing the Serial Mechanism Designer from Inverse Kinematic Solvability Constraints
Authors: Friedman Diana C. W. , Kowalewski Tim , Jovanovic Radivoje , Rosen Jacob , Hannaford Blake
Published: March 2015

This paper presents a fast numerical solution for the inverse kinematics of a serial manipulator. The method is implemented on the C-arm, a manipulator designed for use in robotic surgery. The inverse kinematics solution provides all possible solutions for any six degree-of-freedom serial manipulator, assuming that the forward kinematics are known and that it is possible to solve for the remaining joint angles if one joint angle’s value is known. With a fast numerical method and the current levels of computing power, designing a manipulator with closed-form inverse kinematics is no longer necessary. When designing the C-arm, we therefore chose to weigh other factors, such as actuator size and patient safety, more heavily than the ability to find a closed-form inverse kinematics solution.
Fuzzy Modelling of Knee Joint with Genetic Optimization
Authors: Ibrahim B. S. K. K. , Tokhi M. O. , Huq M. S. , Jailani R. , Gharooni S. C.
Published: March 2015

Modelling of joint properties of lower limbs in people with spinal cord injury is significantly challenging for researchers due to the complexity of the system. The objective of this study is to develop a knee joint model capable of relating electrical parameters to dynamic joint torque as well as knee angle for functional electrical stimulation application. The joint model consists of a segmental dynamic, time-invariant passive properties and uncertain time-variant active properties. The knee joint model structure comprising optimised equations of motion and fuzzy models to represent the passive viscoelasticity and active muscle properties is formulated. The model thus formulated is optimised using genetic optimization, and validated against experimental data. The developed model can be used for simulation of joint movements as well as for control development. The results show that the model developed gives an accurate dynamic characterisation of the knee joint.
Estimation of the Centre of Mass From Motion Capture and Force Plate Recordings: A Study on the Elderly
Authors: Cotton S. , Vanoncini M. , Fraisse P. , Ramdani N. , Demircan E. , Murray A. P. , Keller T.
Published: March 2015

The estimation of the centre of mass position in humans is usually based on biomechanical models developed from anthropometric tables. This method can potentially introduce errors in studies involving elderly people, since the ageing process is typically associated with a modification of the distribution of the body mass. In this paper, an alternative technique is proposed, and evaluated with an experimental study on 9 elderly volunteers. The technique is based on a virtual chain, identified from experimental data and locating the subject's centre of mass. Its configuration defines the location of the centre of mass, and is a function of the anatomical joint angles measured on the subject. This method is a valuable investigation tool in the field of geronto-technology, since it overcomes some of the problems encountered with other CoM estimation methods.
Preventing Ischial Pressure Ulcers: III. Clinical Pilot Study of Chronic Neuromuscular Electrical Stimulation
Authors: Kaplan Hilton M. , Baker Lucinda L. , Rubayi Salah , Loeb Gerald E.
Published: March 2015

Objective:BIONs™ (BIOnic Neurons) are injectable, wireless microstimulators that make chronic BION Active Seating (BAS) possible for pressure ulcer prevention (PUP). Neuromuscular electrical stimulation (NMES) produces skeletal motion and activates trophic factors, counteracting three major etiological mechanisms leading to pressure ulcers (PUs): immobility, soft-tissue atrophy, and ischemia. Companion papers I and II reviewed prior experience with NMES for PUP, and analyzed the biomechanical considerations, respectively. This paper presents a treatment strategy derived from this analysis, and the clinical results of the first three cases.

Methods:Two BIONs implanted (one on inferior gluteal nerve to gluteus maximus (GM), and other on sciatic nerve to hamstrings (HS)), in 3 spinal cord injured (SCI) subjects already undergoing gluteal rotation flaps for PUs. BAS using HS when seated, and BION Conditioning (BC) via GM+HS when non-weightbearing. Follow-up: 1 yr, including 6 mo. treatment window (interface pressure mapping; muscle perfusion scans; MRI, X-ray volume assessments).

Results:Successfully implanted and activated both desired muscle groups, selectively, in all. No PU recurrences or wound complications. Two subjects completed protocol. Mean results: Interface: contact pressure −10%; maximum pressure −20%; peak pressure area −15%. Vascularity: GM +20%, HS +110%. Perfusion: GM +70%, HS +440%. Muscle volume: GM +14%, HS +31%. Buttock soft-tissue padding: +49%. 1 BION failed; 1 BION rotated under GM.

Conclusions:Promising proof-of-concept data supporting the feasibility of implanted microstimulators to achieve sufficiently strong and selective activation of target muscles for PUP. Ultimate goal is prophylactic deployment through bilateral, nonsurgical injection of BIONs in chronically immobile patients.
Simulation of the Lumbar Spine as a Multi-Module Paralel Manipulator
Authors: Ceccarelli M. , Saltarelo R. C. , Carbone G. , Carvalho J. C. M.
Published: March 2015

In this paper a simulation of movements of lumbar spine is proposed by using a model with serially connected parallel manipulators. An analysis has been computed for the human spine structure and its movements, in order to simulate the motions and forces that actuate a spine specifically in the lumbar segment. A mechanical model has been designed with available identified parameters of human spine, by using characteristics of parallel manipulators and spring stiffness. This model is suitable to properly simulate the trunk behavior at macroscopic level but also the smooth behavior of intervertebral discs and actuating motions of muscles and tendons. Simulation results for spring actions and joints reaction forces can give an evaluation of the forces that intervertebral discs supports during motions of a real spine.
Preventing Ischial Pressure Ulcers: II. Biomechanics
Authors: Kaplan Hilton M. , Baker Lucinda L. , Davoodi Rahman , Wong Nga Ting , Loeb Gerald E.
Published: March 2015

Background:Pressure ulcers (PUs) are common and debilitating wounds that arise when immobilized patients cannot shift their weight. Neuromuscular Electrical Stimulation (NMES) has been investigated for Pressure Ulcer Prevention (PUP) for over 20 years. Historically gluteus maximus (GM) has been considered an important actuator in attempting to redistribute seated pressures through NMES.

Methods:Analysis of skeletal biomechanics to quantify the value of GM relative to hamstring hip extensors (HS), using muscle moment models based on torques and rigid body mass estimates from the literature. Surface stimulation experiments (n= 10 + 1,non-paralyzed) to validate model and identify promising stimulation sites and treatment strategies that would approximate healthy biomechanics.

Results:Literature values and Rigid Body Analysis estimate: ~63 Nm extensor torque requirement calculated for complete ipsilateral unloading of the buttocks. Muscle Moment Analysis: GM can provide 70% of total hip extensor torque when walking vs. 18% when seated. HS can provide 100 Nm hip extension torque when seated, exceeding 63 Nm requirement. Surface Stimulation: ipsilateral seated interface pressure mean −26% during HS stimulation vs. +16% with GM; peak pressure area −94% HS vs. +213% GM.

Conclusions:GM activation reduces disuse atrophy and improves circulation, but appears neither required, nor desired, for unloading when seated. HS stimulation alone should be capable of sufficient unloading. This new proposed approach is explored clinically in companion paper III.
Driving Backwards Using a Semi-Autonomous Smart Wheelchair System (DSS): A Clinical Evaluation
Authors: Sharma Vinod , Simpson Richard , LoPresti Edmund , Schmeler Mark
Published: March 2015

Some wheelchair users have difficulty looking backward when backing up in confined spaces due to limited neck range of motion or low vision, which can lead to collisions which may result in personal injury or property damage. The Drive Safe System (DSS) was evaluated in a controlled laboratory setting with blindfolded able-bodied individuals on various backward driving tasks. Performance with the DSS was compared with a standard white cane used for navigation assistance by people with visual impairment. Results indicate that the DSS significantly reduced the number of collisions compared to using a cane (p= 0.0001) alone. There was no difference in task completion time when participants were using the cane or the DSS (p= 0.915). Users rated the DSS favourably as they experience less total workload (p= 0.026), less physical demand (p= 0.006), felt less frustrated (p= 0.002) and put less effort (p= 0.007) to achieve better performance when using the DSS, compared to using a cane. These findings suggest that the DSS can be a viable powered mobility solution for wheelchair users with visual impairments.
Mobility Assistance for Older People
Authors: Eck Daniel , Schilling Klaus , Abdul-Majeed Ahmad , Thielecke Jörn , Richter Phillipp , Boronat Javier Gutiérrez , Schens Irina , Thomas Bernd , Williger Bettina , Lang Frieder R.
Published: March 2015

This paper describes the development of a scooter supporting the mobility of older people. The scooter is equipped with a drive assistance system and a special scooter navigation system. The drive assistance system consists of a velocity controller, a steering controller, and a collision avoidance system. In this paper it is demonstrated how the challenging control and steering tasks are modified to increase safety for older people. A special scooter navigation system is presented, to support elderly people in navigating on a safe route through the city using sidewalks, pedestrian lights and crosswalks. For extended positioning requirements a hybrid positioning system was developed combining GPS, WLAN, and inertial sensor data. By combination of these technical improvements it is demonstrated how older people are able to preserve their self-determined and independent life. Usability research was done with focus groups in order to become familiar with global user demands and expectations towards a mobility assistance system. Results show that the system components are expected to assist the user in navigation, steering and speed control rather than to take complete control on the driving situation.
Combination of Annealing Particle Filter and Belief Propagation for 3D Upper Body Tracking
Authors: Renna Ilaria , Chellali Ryad , Achard Catherine
Published: March 2015

3D upper body pose estimation is a topic greatly studied by the computer vision society because it is useful in a great number of applications, mainly for human robots interactions including communications with companion robots. However there is a challenging problem: the complexity of classical algorithms that increases exponentially with the dimension of the vectors’ state becomes too difficult to handle. To tackle this problem, we propose a new approach that combines several annealing particle filters defined independently for each limb and belief propagation method to add geometrical constraints between individual filters. Experimental results on a real human gestures sequence will show that this combined approach leads to reliable results.
Quantification of Subjective Scaling of Friction Using a Fingertip Biomechanical Model
Authors: Abdolvahab Mohammad
Published: March 2015

Subjective scaling of friction is important in many applications in haptic technology. A nonhomogeneous biomechanical finite element model of fingertip is proposed in order to predict neural response of sensitive mechanoreceptors to frictional stimuli (Slowly Adapting SAII receptors under the glabrous skin). In a guided psychophysical experiment, ten human subjects were asked to scale several standard surfaces based on the perception of their frictional properties. Contact forces deployed during the exploratory time of one of the participants were captured in order to estimate required parameters for the model of contact in the simulation procedure. Consequently, the strain energy density at the location of a selective mechanoreceptor in the finite element model as a measure of discharge rate of the neural unit was compared to the subject’s perceptual evaluation of the relevant stimuli. It was observed that the subject’s scores correlate with the discharge rate of the given receptor.
Visual Attention Mechanism for a Social Robot
Authors: Bandera Juan Pedro , Marfil R. , Palomino Antonio Jesús , Vázquez-Martín Ricardo , Bandera Antonio
Published: March 2015

This paper describes a visual perception system for a social robot. The central part of this system is an artificial attention mechanism that discriminates the most relevant information from all the visual information perceived by the robot. It is composed by three stages. At the preattentive stage, the concept of saliency is implemented based on ‘proto-objects’ [37]. From these objects, different saliency maps are generated. Then, the semiattentive stage identifies and tracks significant items according to the tasks to accomplish. This tracking process allows to implement the ‘inhibition of return’. Finally, the attentive stage fixes the field of attention to the most relevant object depending on the behaviours to carry out. Three behaviours have been implemented and tested which allow the robot to detect visual landmarks in an initially unknown environment, and to recognize and capture the upper-body motion of people interested in interact with it.
TowardsPhysarumEngines
Authors: Tsuda Soichiro , Jones Jeff , Adamatzky Andrew
Published: March 2015

The slime mouldPhysarumpolycephalumis a suitable candidate organism for soft-matter robotics because it exhibits controllable transport, movement and guidance behaviour.Physarummay be considered as a smart computing and actuating material since both its motor and control systems are distributed within its undifferentiated tissue and can survive trauma such as excision, fission and fusion of plasmodia. Thus it may be suitable for exploring the generation and distribution of micro-actuation in individual units or planar arrays. We experimentally show how the plasmodium ofPhysarumis shaped to execute controllable oscillatory transport behaviour applicable in small hybrid engines. We measure the lifting force of the plasmodium and demonstrate how protoplasmic transport can be influenced by externally applied illumination stimuli. We provide an exemplar vehicle mechanism by coupling the oscillations of the plasmodium to drive the wheels of a Braitenberg vehicle and use light stimuli to effect a steering mechanism. Using a particle model ofPhysarumwe show how emergent travelling wave patterns produced by competing oscillatory domains may be used to to generate spatially represented actuation patterns. We demonstrate different patterns of controllable motion, including linear, reciprocal, rotational and helical, and demonstrate in simulation how dynamic oscillatory patterns may be translated into motive forces for simple transport of substances within a patterned environment.
Robotic Pectoral Fin Thrust Vectoring Using Weighted Gait Combinations
Authors: Palmisano John S. , Geder Jason D. , Ramamurti Ravi , Sandberg William C. , Ratna Banahalli
Published: March 2015

A method was devised to vector propulsion of a robotic pectoral fin by means of actively controlling fin surface curvature. Separate flapping fin gaits were designed to maximize thrust for each of three different thrust vectors: forward, reverse, and lift. By using weighted combinations of these three pre-determined main gaits, new intermediate hybrid gaits for any desired propulsion vector can be created with smooth transitioning between these gaits. This weighted gait combination (WGC) method is applicable to other difficult-to-model actuators. Both 3D unsteady computational fluid dynamics (CFD) and experimental results are presented.