4,351 research outputs found
On Advanced Mobility Concepts for Intelligent Planetary Surface Exploration
Surface exploration by wheeled rovers on Earth's Moon (the two Lunokhods) and Mars (Nasa's Sojourner and the two MERs) have been followed since many years already very suc-cessfully, specifically concerning operations over long time. However, despite of this success, the explored surface area was very small, having in mind a total driving distance of about 8 km (Spirit) and 21 km (Opportunity) over 6 years of operation. Moreover, ESA will send its ExoMars rover in 2018 to Mars, and NASA its MSL rover probably this year. However, all these rovers are lacking sufficient on-board intelligence in order to overcome longer dis-tances, driving much faster and deciding autonomously on path planning for the best trajec-tory to follow. In order to increase the scientific output of a rover mission it seems very nec-essary to explore much larger surface areas reliably in much less time. This is the main driver for a robotics institute to combine mechatronics functionalities to develop an intelligent mo-bile wheeled rover with four or six wheels, and having specific kinematics and locomotion suspension depending on the operational terrain of the rover to operate. DLR's Robotics and Mechatronics Center has a long tradition in developing advanced components in the field of light-weight motion actuation, intelligent and soft manipulation and skilled hands and tools, perception and cognition, and in increasing the autonomy of any kind of mechatronic systems. The whole design is supported and is based upon detailed modeling, optimization, and simula-tion tasks. We have developed efficient software tools to simulate the rover driveability per-formance on various terrain characteristics such as soft sandy and hard rocky terrains as well as on inclined planes, where wheel and grouser geometry plays a dominant role. Moreover, rover optimization is performed to support the best engineering intuitions, that will optimize structural and geometric parameters, compare various kinematics suspension concepts, and make use of realistic cost functions like mass and consumed energy minimization, static sta-bility, and more. For self-localization and safe navigation through unknown terrain we make use of fast 3D stereo algorithms that were successfully used e.g. in unmanned air vehicle ap-plications and on terrestrial mobile systems. The advanced rover design approach is applica-ble for lunar as well as Martian surface exploration purposes. A first mobility concept ap-proach for a lunar vehicle will be presented
A Multimodal Perception Framework for Users Emotional State Assessment in Social Robotics
In this work, we present an unobtrusive and non-invasive perception framework based on the synergy between two main acquisition systems: the Touch-Me Pad, consisting of two electronic patches for physiological signal extraction and processing; and the Scene Analyzer, a visual-auditory perception system specifically designed for the detection of social and emotional cues. It will be explained how the information extracted by this specific kind of framework is particularly suitable for social robotics applications and how the system has been conceived in order to be used in human-robot interaction scenarios
The design of a hybrid DC motor/SMA actuated robotic hand based on physiological and anatomical synergies
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Includes bibliographical references (p. 73-74).A new approach to the design and control of multi-fingered hands using hybrid DC motor-Shape Memory Alloy (SMA) array actuators is presented in this thesis. The fundamental design concept is based on the principle of motor control synergy, a biomechanics terminology for coordinated motion generation. Principal component analysis is used for determining the most significant direction as well as the residual directions. A single DC motor is used for driving multiple fingers at a particular velocity distribution over a vast number of finger joints corresponding to the direction of the most significant synergy. SMA array actuators are used for driving the fingers in the residual directions. Although many actuator axes are needed for spanning the residual space, the required strokes are much shorter than the most significant direction; compact and high energy-density SMA actuators meet these requirements. The thesis presents synergistic integration of these two types of actuators having diverse characteristics. This allows us to embed all the actuators and transmission mechanisms in the palm, eliminating a bundle of tendons crossing over the wrist joints. An initial prototype hand is designed and built.by Josiah Benjamin Rosmarin.S.M
DEVELOPMENT OF A SOFT PNEUMATIC ACTUATOR FOR MODULAR ROBOTIC MECHANISMS
Soft robotics is a widely and rapidly growing field of research today. Soft
pneumatic actuators, as a fundamental element in soft robotics, have gained
huge popularity and are being employed for the development of soft robots.
During the last decade, a variety of hyper-elastic robotic systems have been
realized. As the name suggests, such robots are made up of soft materials,
and do not have any underlying rigid mechanical structure. These robots are
actuated employing various methods like pneumatic, electroactive, jamming
etc. Generally, in order to achieve a desired mechanical response to produce
required actuation or manipulation, two or more materials having different
stiffness are utilized to develop a soft robot. However, this method introduces
complications in the fabrication process as well as in further design
flexibility and modifications. The current work presents a design scheme of
a soft robotic actuator adapting an easier fabrication approach, which is economical
and environment friendly as well.
The purpose is the realization of a soft pneumatic actuator having functional
ability to produce effective actuation, and which is further employable
to develop modular and scalable mechanisms. That infers to scrutinize the
profile and orientation of the internal actuation cavity and the outer shape of
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the actuator. Utilization of a single material for this actuator has been considered
to make this design scheme convenient. A commercial silicone rubber
was selected which served for an economical process both in terms of the
cost as well as its accommodating fabrication process through molding. In
order to obtain the material behavior, \u2018Ansys Workbench 17.1 R
\u2019 has been
used. Cubic outline for the actuator aided towards the realization of a body
shape which can easily be engaged for the development of modular mechanisms
employing multiple units. This outer body shape further facilitates
to achieve the stability and portability of the actuator. The soft actuator has
been named \u2018Soft Cubic Module\u2019 based on its external cubic shape. For the
internal actuation cavity design, various shapes, such as spherical, elliptical
and cylindrical, were examined considering their different sizes and orientations
within the cubic module. These internal cavities were simulated in order
to achieve single degree of freedom actuation. That means, only one face
of the cube is principally required to produce effective deformation. \u2018Creo
Perametric 3.0 M 130\u2019 has been used to design the model and to evaluate the
performance of actuation cavities in terms of effective deformation and the
resulting von-mises stress. Out of the simulated profiles, cylindrical cavity
with desired outcomes has been further considered to design the soft actuator.
\u2018Ansys Workbench 17.1 R
\u2019 environment was further used to assess the
performance of cylindrical actuation cavity. Evaluation in two different simulation
environments helped to validate the initially achieved results. The
developed soft cubic actuator was then employed to develop different mechanisms
in a single unit configuration as well as multi-unit robotic system
developments.
This design scheme is considered as the first tool to investigate its capacity
to perform certain given tasks in various configurations. Alongside
its application as a single unit gripper and a two unit bio-mimetic crawling
mechanism, this soft actuator has been employed to realize a four degree
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of freedom robotic mechanism. The formation of this primitive soft robotic
four axis mechanism is being further considered to develop an equivalent
mechanism similar to the well known Stewart platform, with advantages of
compactness, simpler kinematics design, easier control, and lesser cost.
Overall, the accomplished results indicate that the design scheme of Soft
Cubic Module is helpful in realizing a simple and cost-effective soft pneumatic
actuator which is modular and scalable. Another favourable point of
this scheme is the use of a single material with convenient fabrication and
handling
On the development of a cybernetic prosthetic hand
The human hand is the end organ of the upper limb, which in humans serves the important
function of prehension, as well as being an important organ for sensation and communication.
It is a marvellous example of how a complex mechanism can be implemented,
capable of realizing very complex and useful tasks using a very effective combination of
mechanisms, sensing, actuation and control functions.
In this thesis, the road towards the realization of a cybernetic hand has been presented.
After a detailed analysis of the model, the human hand, a deep review of the state of the
art of artificial hands has been carried out. In particular, the performance of prosthetic
hands used in clinical practice has been compared with the research prototypes, both for
prosthetic and for robotic applications. By following a biomechatronic approach, i.e. by
comparing the characteristics of these hands with the natural model, the human hand, the
limitations of current artificial devices will be put in evidence, thus outlining the design
goals for a new cybernetic device.
Three hand prototypes with a high number of degrees of freedom have been realized and
tested: the first one uses microactuators embedded inside the structure of the fingers, and
the second and third prototypes exploit the concept of microactuation in order to increase
the dexterity of the hand while maintaining the simplicity for the control. In particular, a
framework for the definition and realization of the closed-loop electromyographic control of
these devices has been presented and implemented.
The results were quite promising, putting in evidence that, in the future, there could
be two different approaches for the realization of artificial devices. On one side there
could be the EMG-controlled hands, with compliant fingers but only one active degree of
freedom. On the other side, more performing artificial hands could be directly interfaced
with the peripheral nervous system, thus establishing a bi-directional communication with
the human brain
ReHand - a portable assistive rehabilitation hand exoskeleton
This dissertation presents a synthesis of a novel underactuated exoskeleton (namely ReHand2) thought and designed for a task-oriented rehabilitation and/or for empower the human hand.
The first part of this dissertation shows the current context about the robotic rehabilitation with a focus on hand pathologies, which influence the hand capability. The chapter is concluded with the presentation of ReHand2.
The second chapter describes the human hand biomechanics. Starting from the definition of human hand anatomy, passing through anthropometric data, to taxonomy on hand grasps and finger constraints, both from static and dynamic point of view. In addition, some information about the hand capability are given.
The third chapter analyze the current state of the art in hand exoskeleton for rehabilitation and empower tasks. In particular, the chapter presents exoskeleton technologies, from mechanisms to sensors, passing though transmission and actuators. Finally, the current state of the art in terms of prototype and commercial products is presented.
The fourth chapter introduces the concepts of underactuation with the basic explanation and the classical notation used typically in the prosthetic field. In addition, the chapter describe also the most used differential elements in the prosthetic, follow by a statical analysis. Moreover typical transmission tree at inter-finger level as well as the intra- finger underactuation are explained .
The fifth chapter presents the prototype called ReHand summarizing the device description and explanation of the working principle. It describes also the kinetostatic analysis for both, inter- and the intra-finger modules. in the last section preliminary results obtained with the exoskeleton are shown and discussed, attention is pointed out on prototype’s problems that have carry out at the second version of the device.
The sixth chapter describes the evolution of ReHand, describing the kinematics and dynamics behaviors. In particular, for the mathematical description is introduced the notation used in order to analyze and optimize the geometry of the entire device. The introduced model is also implemented in Matlab Simulink environment. Finally, the chapter presents the new features.
The seventh chapter describes the test bench and the methodologies used to evaluate the device statical, and dynamical performances. The chapter presents and discuss the experimental results and compare them with simulated one.
Finally in the last chapter the conclusion about the ReHand project are proposed as well as the future development. In particular, the idea to test de device in relevant environments. In addition some preliminary considerations about the thumb and the wrist are introduced, exploiting the possibility to modify the entire layout of the device, for instance changing the actuator location
Design, development and deployment of a hand/wrist exoskeleton for home-based rehabilitation after stroke - SCRIPT project
YesChanges in world-wide population trends have provided new demands for new technologies in areas
such as care and rehabilitation. Recent developments in the the field of robotics for neurorehabilitation
have shown a range of evidence regarding usefulness of these technologies as a tool to augment
traditional physiotherapy. Part of the appeal for these technologies is the possibility to place a
rehabilitative tool in one’s home, providing a chance for more frequent and accessible technologies
for empowering individuals to be in charge of their therapy.
Objective: this manuscript introduces the Supervised Care and Rehabilitation Involving Personal
Tele-robotics (SCRIPT) project. The main goal is to demonstrate design and development steps
involved in a complex intervention, while examining feasibility of using an instrumented orthotic
device for home-based rehabilitation after stroke.
Methods: the project uses a user-centred design methodology to develop a hand/wrist
rehabilitation device for home-based therapy after stroke. The patient benefits from a dedicated
user interface that allows them to receive feedback on exercise as well as communicating with
the health-care professional. The health-care professional is able to use a dedicated interface
to send/receive communications and remote-manage patient’s exercise routine using provided
performance benchmarks. Patients were involved in a feasibility study (n=23) and were instructed to
use the device and its interactive games for 180 min per week, around 30 min per day, for a period of
6 weeks, with a 2-months follow up. At the time of this study, only 12 of these patients have finished
their 6 weeks trial plus 2 months follow up evaluation.
Results: with the “use feasibility” as objective, our results indicate 2 patients dropping out due
to technical difficulty or lack of personal interests to continue. Our frequency of use results indicate
that on average, patients used the SCRIPT1 device around 14 min of self-administered therapy a day.
The group average for the system usability scale was around 69% supporting system usability.
Conclusions: based on the preliminary results, it is evident that stroke patients were able to use the
system in their homes. An average of 14 min a day engagement mediated via three interactive games
is promising, given the chronic stage of stroke. During the 2nd year of the project, 6 additional games
with more functional relevance in their interaction have been designed to allow for a more variant context for interaction with the system, thus hoping to positively influence the exercise duration.
The system usability was tested and provided supporting evidence for this parameter. Additional
improvements to the system are planned based on formative feedback throughout the project and
during the evaluations. These include a new orthosis that allows a more active control of the amount
of assistance and resistance provided, thus aiming to provide a more challenging interaction.This work has been partially funded under Grant FP7-ICT-288698(SCRIPT) of the European Community Seventh Framework Programme
Actuation Technologies for Soft Robot Grippers and Manipulators: A Review
Purpose of Review The new paradigm of soft robotics has been widely developed in the international robotics community. These
robots being soft can be used in applications where delicate yet effective interaction is necessary. Soft grippers and manipulators
are important, and their actuation is a fundamental area of study. The main purpose of this work is to provide readers with fast
references to actuation technologies for soft robotic grippers in relation to their intended application.
Recent Findings The authors have surveyed recent findings on actuation technologies for soft grippers. They presented six major
kinds of technologies which are either used independently for actuation or in combination, e.g., pneumatic actuation combined
with electro-adhesion, for certain applications.
Summary A review on the latest actuation technologies for soft grippers and manipulators is presented. Readers will get a guide
on the various methods of technology utilization based on the application
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