Showing papers in "Applied Bionics and Biomechanics in 2008"
TL;DR: In this article, the authors discuss the capabilities of soft robots, describe examples from nature that provide biological inspiration, surveys the state of the art and outlines existing challenges in soft robot design, modelling, fabrication and control.
Abstract: Traditional robots have rigid underlying structures that limit their ability to interact with their environment. For example, conventional robot manipulators have rigid links and can manipulate objects using only their specialised end effectors. These robots often encounter difficulties operating in unstructured and highly congested environments. A variety of animals and plants exhibit complex movement with soft structures devoid of rigid components. Muscular hydrostats e.g. octopus arms and elephant trunks are almost entirely composed of muscle and connective tissue and plant cells can change shape when pressurised by osmosis. Researchers have been inspired by biology to design and build soft robots. With a soft structure and redundant degrees of freedom, these robots can be used for delicate tasks in cluttered and/or unstructured environments. This paper discusses the novel capabilities of soft robots, describes examples from nature that provide biological inspiration, surveys the state of the art and outlines existing challenges in soft robot design, modelling, fabrication and control.
1,295 citations
TL;DR: In this paper, the influence of an endoscope on the peristaltic flow of a particle -fluid suspension as blood model through tubes is investigated theoretically, where the inner tube is uniform, rigid and moving with a constant velocity V0, whereas the outer non-uniform tube has a sinusoidal wave travelling down its wall.
Abstract: This study looks at the influence of an endoscope on the peristaltic flow of a particle--fluid suspension as blood model through tubes. A long wavelength approximation through a uniform and non-uniform infinite annulus filled with an incompressible viscous and Newtonian fluid mixed with rigid spherical particles of identical size is investigated theoretically. The inner tube is uniform, rigid and moving with a constant velocity V0, whereas the outer non-uniform tube has a sinusoidal wave travelling down its wall. The axial velocity of the fluid phase uf, particulate phase up and the pressure gradients have been obtained in terms of the dimensionless flow rate \bar{Q}, the amplitude ratio φ, particle concentration C, the velocity constant V0 and the radius ratio ∈ the ratio between the radius of the inner tube and the radius of the outer one at the inlet. Numerical calculations for various values of the physical parameters of interest are carried out for the pressure rise and the friction force on the inner and the outer tubes.
39 citations
TL;DR: An example of how a combination of animal kinematics, neural patterning and constitutive modelling of tissues can be used to explore motor control in the caterpillar, Manduca sexta.
Abstract: The development of truly biomimetic robots requires that soft materials be incorporated into the mechanical design and also used as an integral part of the motor control system. One approach to this challenge is to identify how soft animals control their movements and then apply the found principles in robotic applications. Here I show an example of how a combination of animal kinematics, neural patterning and constitutive modelling of tissues can be used to explore motor control in the caterpillar, Manduca sexta. Although still in the early stages, these findings are being used to design and fabricate a new type of robot that does not have a rigid skeleton and is structured entirely from soft or compliant materials. It is hoped that this new robotic platform will promote the development of actuators, sensors and electronics that are compatible with soft materials.
38 citations
TL;DR: In this article, a biologically inspired solution that does not need such a body model is proposed by using implicit communication through the body mechanics embodiment and a local positive velocity feedback strategy LPVF on the single joint level.
Abstract: In a multilegged walking robot several legs usually have ground contact and thereby form a closed kinematic chain. The control of such a system is generally assumed to require the explicit calculation of the body kinematics. Such a computation requires knowledge concerning all relevant joint angles as well as the segment lengths. Here, we propose a biologically inspired solution that does not need such a body model. This is done by using implicit communication through the body mechanics embodiment and a local positive velocity feedback strategy LPVF on the single joint level. In this control scheme the locally measured joint velocity of an elastic joint is fed into the same joint during the next time step to maintain the movement. At the same time, an additional part of this joint controller observes the mechanical joint power to confine the positive feedback. This solution does not depend on changes of the geometry, e.g. length of individual segments, and allows for a simple solution of negotiation of curves. The principle is tested in a dynamics simulation on a six-legged walker and, for the first time, also on a real robot.
38 citations
TL;DR: In this paper, the peristaltic transport of a micropolar fluid in an annular region is investigated under low Reynolds number and long wavelength approximations, and closed form solutions are obtained for the velocity and the microrotation components, as well as the stream function.
Abstract: A serious pathological condition is encountered when some blood constituents deposited on the blood vessels get detached from the wall, join the blood stream again and form a clot. Study of the peristaltic transport of a micropolar fluid in an annular region is investigated under low Reynolds number and long wavelength approximations. We model a small artery as a tube having a sinusoidal wave travelling down its wall and a clot model inside it. Closed form solutions are obtained for the velocity and the microrotation components, as well as the stream function, and they contain new additional parameters, namely, δ, the height of the clot, N, the coupling number and m, the micropolar parameter. The pressure rise and friction force on the inner and the outer tubes have been discussed for various values of the physical parameters of interest.
18 citations
TL;DR: In this paper, a robotic honeybee was designed to mimic the bee dance communication system, and a tracking system was developed to extract real bee dance trajectories recorded with high-speed video cameras.
Abstract: We have designed a robotic honeybee to mimic the bee dance communication system. To achieve this goal, a tracking system has been developed to extract real bee dance trajectories recorded with high-speed video cameras. The results have been analysed to find the essential properties required for the prototype robot. Putative signals in the dance communication have been identified from the literature. Several prototypes were built with successive addition of more features or improvement of existing components. Prototypes were tested in a populated beehive results were documented using high-speed camera recordings. A substantial innovation is a visual feedback system that helps the robot to minimise collisions with other bees.
16 citations
TL;DR: In this paper, a method for learning potential-based policies from constrained motion data is presented, combining observations from a variety of contexts where different constraints are in force, to learn the underlying unconstrained policy in form of its potential function.
Abstract: Movement generation that is consistent with observed or demonstrated behaviour is an efficient way to seed movement planning in complex, high-dimensional movement systems like humanoid robots. We present a method for learning potential-based policies from constrained motion data. In contrast to previous approaches to direct policy learning, our method can combine observations from a variety of contexts where different constraints are in force, to learn the underlying unconstrained policy in form of its potential function. This allows us to generalise and predict behaviour where novel constraints apply. We demonstrate our approach on systems of varying complexity, including kinematic data from the ASIMO humanoid robot with 22 degrees of freedom.
10 citations
TL;DR: A new design allowing a flexion extension range of over 120 degrees was designed and is used for analysis and the results obtained were very satisfactory and based on these results the models have been recommended for prototyping.
Abstract: The application of finite-element modelling in medical applications has been evolving as a field of high importance in recent times. Total knee arthroplasty TKA has been in existence for over 6 decades. The generic artificial knee implants used in the TKA have a restricted range of motion of around 90 degrees. A new design allowing a flexion extension range of over 120 degrees was designed and is used for analysis. Loading conditions of 10 times the body weight are considered. The finite-element analyses of the designs were carried out based on standard biomaterials used in orthopaedic implants. The results of the analyses were used in identifying areas of extreme stress within the design and the spots prone to higher deformation. On the basis of these results slight modification of the designs was carried out. The results are also verified whether the body is within the linear deformation levels. The results obtained were very satisfactory and based on these results the models have been recommended for prototyping.
8 citations
TL;DR: In this article, a cable-based manipulator is proposed for application in rehabilitation therapies, which can be used to aid motion or as a monitoring/training system in rehabilitation therapy, and it can help older people, patients or disabled people in the sit-to-stand transfer.
Abstract: In this study, cable-based manipulators are proposed for application in rehabilitation therapies. Cable-based manipulators show good features that are very useful when the system has to interact with humans. In particular, they can be used to aid motion or as monitoring/training systems in rehabilitation therapies. Modelling and simulation of both active and passive cable-based parallel manipulators are presented for an application to help older people, patients or disabled people in the sit-to-stand transfer and as a monitoring/training system. Experimental results are presented by using built prototypes.
7 citations
TL;DR: A mechanism capable of reproducing voluntary human reaching motions is introduced along with the procedural method of implementing the coupled motions that exist within the human shoulder complex and shoulder--elbow complex.
Abstract: A challenge that is gaining interest in robotics is the development of humanoids, which are robots that assume an anthropomorphic form. A difficulty with humanoid design is the kinematic interpretation of human joints and the development of mechanisms that can mimic human motion. The focus of this work is the development of a kinematic description of the shoulder--elbow complex. A mechanism capable of reproducing voluntary human reaching motions is introduced along with the procedural method of implementing the coupled motions that exist within the human shoulder complex and shoulder--elbow complex. Experimental results are presented highlighting the accuracy of this mechanism along with the similarities to human configurations.
7 citations
TL;DR: An advanced control system is presented for the full-scale humanoid robot RH-1 so that it can perform tasks in cooperation with humans and is intended to be put into operation in real working environments where humans and robots should share the same space.
Abstract: The full-scale humanoid robot RH-1 has been totally developed in the University Carlos III of Madrid. In this paper we present an advanced control system for this robot so that it can perform tasks in cooperation with humans. The collaborative tasks are carried out in a semi-autonomous way and are intended to be put into operation in real working environments where humans and robots should share the same space. Before presenting the control strategy, the kinematic model and a simplified dynamic model of the robot are presented. All the models and algorithms are verified by several simulations and experimental results.
TL;DR: In this article, the authors present a control method for regulating both the forward speed and the apex height of a one-legged hopping robot using only a single actuator, based on a dynamic model of the hopping robot and making use of the dynamic coupling of the vertical and forward motions of the robot.
Abstract: In this paper we present and experimentally validate a control method for regulating both the forward speed and the apex height of a one-legged hopping robot, using only a single actuator. The control method is based on a dynamic model of the hopping robot and makes use of the dynamic coupling of the vertical and forward motions of the robot. The control is applied first to a simulated model of the robot and shown to track a desired forward robot speed and a desired apex height. Then the SAHR single actuator hopping robot hardware is introduced and is used as an experimental platform with which to evaluate the performance of the control method. The control method is applied to the physical setup and is shown to lead to a stable hopping gait with a desired forward speed and apex height, despite the unmodelled disturbances met on the laboratory floor.
TL;DR: This paper decouple the motion-planning problem of humanoid robots into two sub-problems, namely topological state planning and detailed motion planning, and proposes several basic states, including lying, sitting, standing and handstanding abstracted from the daily exercises of human beings.
Abstract: In this paper, we decouple the motion-planning problem of humanoid robots into two sub-problems, namely topological state planning and detailed motion planning. The state classification plays a key role for the first sub-problem. We propose several basic states, including lying, sitting, standing and handstanding, abstracted from the daily exercises of human beings. Each basic state is classified further from the topological point of view. Furthermore, generalised function GF set theory is applied with the aim of analysing the kinematic characteristics of the end effectors for each state, and meaningful names are assigned for each state. Finally a topological state-planning example is given to show the effectiveness of this methodology. The results show that the large amounts of states can be described using assigned names, which leads to systematic and universal description of the states for humanoid robots.
TL;DR: The ultrasonic technique was able to detect a decrease in the structural stiffness of the patellar tendon associated with PFPS, and the decrease in tendon stiffness was moderately correlated with the length of symptoms in these individuals.
Abstract: The objective of this study was to utilise an ultrasonic technique to assess the effect of patellofemoral pain syndrome PFPS on the mechanical properties of the patellar tendon. Seven subjects with PFPS and seven matched control subjects volunteered to participate in this study. Subjects were asked to perform isometric maximal voluntary contractions of the knee extensors while their knee extension torque was monitored and the displacement of the patellar tendon was recorded with an ultrasonic system. Our results showed significantly lower tendon stiffness by ~30% in the PFPS subjects. Although tendon secant modulus was lower by 34% in the PFPS subjects, the difference was not statistically significant. Therefore, we conclude that the ultrasonic technique was able to detect a decrease in the structural stiffness of the patellar tendon associated with PFPS. The decrease in tendon stiffness was moderately correlated with the length of symptoms in these individuals.
TL;DR: A new measure is developed that demonstrates the difference between smooth and non-smooth physical interactions and shows significant differences between experts and beginners in human--robot interaction.
Abstract: 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 CB2 robot 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.
TL;DR: In this article, the authors analyse the actuator as a bio-inspired 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.
Abstract: 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.
TL;DR: Different roles for two mechanisms in the simulated walkers are revealed, which will not only increase the possibility of realising artificial reflexes for paralysed individuals, but also bring new insights into the field of motor control.
Abstract: 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.
TL;DR: The NGOMSL modelled human-humanoid interaction design of Robo-Erectus Junior was evaluated and the results showed that the interaction design was able to find faults in an average time of 23.84 s and be able to detect the fault within the 60 s in 100% of the cases.
Abstract: In the field of human-computer interaction, the Natural Goals, Operators, Methods, and Selection rules Language NGOMSL model is one of the most popular methods for modelling knowledge and cognitive processes for rapid usability evaluation. The NGOMSL model is a description of the knowledge that a user must possess to operate the system represented as elementary actions for effective usability evaluations. In the last few years, mobile robots have been exhibiting a stronger presence in commercial markets and very little work has been done with NGOMSL modelling for usability evaluations in the human-robot interaction discipline. This paper focuses on extending the NGOMSL model for usability evaluation of human-humanoid robot interaction in the soccer robotics domain. The NGOMSL modelled human-humanoid interaction design of Robo-Erectus Junior was evaluated and the results of the experiments showed that the interaction design was able to find faults in an average time of 23.84 s. Also, the interaction design was able to detect the fault within the 60 s in 100% of the cases. The Evaluated Interaction design was adopted by our Robo-Erectus Junior version of humanoid robots in the RoboCup 2007 humanoid soccer league.
TL;DR: In this article, a swarm intelligence is used to adjust the parameters of the membership functions used in the adaptive fuzzy controller, and 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 controllers.
Abstract: 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.
TL;DR: In this paper, a course in bionics at the "Politehnica" University of Bucharest is described, which was supported by the expertise of the German "Bionik-Kompetenz-Netz", one of the leading organizations in the field.
Abstract: 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.
TL;DR: In this article, a piezoelectric ceramic system [Pb0.978--yLa0.012Ba0.01Sry][Zr0.534Ti0.4660]O3 PLBSZNT has been fabricated for use in medical diagnostics applications.
Abstract: The piezoelectric ceramic system [Pb0.978--yLa0.012Ba0.01Sry][Zr0.534Ti0.4660.987Nb0.008]O3 PLBSZNT has been fabricated for use in medical diagnostics applications. The fundamental pre-requisites are high-density, high dielectric constant and high piezoelectric properties that serve as compatible ceramic materials for medical diagnostic applications. It is essential for sensitive transducers that the piezoelectric ceramics must efficiently convert between electrical and mechanical energy, and so the electromechanical coupling coefficients should be high, as the fabrication process of tiny elements for medical arrays must be carried out without damaging the material and its properties. In our study, Sr-modified PLBZNT had shown single ferroelectric tetragonal phase. An analysis of different Sr doping concentration is reported, and the high dielectric permittivity, low dielectric loss along with high electromechanical properties indicate that PLBSZNT is suitable for medical diagnostic applications as well as sensors and actuators.
TL;DR: In this article, a biped walking robot has been constructed to reproduce human gait patterns from data acquired in gait laboratories. But the robot dimensions have been chosen in order to guarantee anthropomorphic proportions and then to help health professionals to conduct gait studies.
Abstract: Human gait analysis is one of the resources that may be used in the study and treatment of pathologies of the locomotive system. This paper deals with the modelling and control aspects of the design, construction and testing of a biped walking robot conceived to, in limited extents, reproduce the human gait. Robot dimensions have been chosen in order to guarantee anthropomorphic proportions and then to help health professionals in gait studies. The robot has been assembled with low-cost components and can reproduce, in an assisted way, real-gait patterns generated from data previously acquired in gait laboratories. Part of the simulated and experimental results are addressed to demonstrate the ability of the biped robot in reproducing normal and pathological human gait.