422 research outputs found
Analysis of a rotating advanced-technology space station for the year 2025
An analysis is made of several aspects of an advanced-technology rotating space station configuration generated under a previous study. The analysis includes examination of several modifications of the configuration, interface with proposed launch systems, effects of low-gravity environment on human subjects, and the space station assembly sequence. Consideration was given also to some aspects of space station rotational dynamics, surface charging, and the possible application of tethers
Design, fabrication and control of soft robots
Conventionally, engineers have employed rigid materials to fabricate precise, predictable robotic systems, which are easily modelled as rigid members connected at discrete joints. Natural systems, however, often match or exceed the performance of robotic systems with deformable bodies. Cephalopods, for example, achieve amazing feats of manipulation and locomotion without a skeleton; even vertebrates such as humans achieve dynamic gaits by storing elastic energy in their compliant bones and soft tissues. Inspired by nature, engineers have begun to explore the design and control of soft-bodied robots composed of compliant materials. This Review discusses recent developments in the emerging field of soft robotics.National Science Foundation (U.S.) (Grant IIS-1226883
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
Soft manipulators and grippers: A review
Soft robotics is a growing area of research which utilizes the compliance and adaptability of soft structures to develop highly adaptive robotics for soft interactions. One area in which soft robotics has the ability to make significant impact is in the development of soft grippers and manipulators. With an increased requirement for automation, robotics systems are required to perform task in unstructured and not well defined environments; conditions which conventional rigid robotics are not best suited. This requires a paradigm shift in the methods and materials used to develop robots such that they can adapt to and work safely in human environments. One solution to this is soft robotics, which enables soft interactions with the surroundings while maintaining the ability to apply significant force. This review paper assesses the current materials and methods, actuation methods and sensors which are used in the development of soft manipulators. The achievements and shortcomings of recent technology in these key areas are evaluated, and this paper concludes with a discussion on the potential impacts of soft manipulators on industry and society
Design of an adaptive force and stiffness controlled compliant device for robotic polishing
Polishing is a repetitive task done in an unhealthy environment. Often more than half of the manufacturing time is required to polish a die. The manual polishing process is a tedious work actively rely on a skilled human worker. Industrial Robot has replaced the human in performing these tasks. For robotic polishing to control the polishing force, an active compliant device is used. Due to the compressibility of air, a pneumatic system is preferred as the actuator of the device. The force of the actuator is controlled by regulating air pressure in both chambers of the cylinder. However, to improve productivity, a constant polishing force alone is not sufficient, the stiffness is also considered. The current work involved a new adaptive approach to model and control of the force and stiffness of an active compliant device. The device can adaptively control the compliance and force in real time compensating the gravitational effect due to the mass, gravity, and orientation of the tool. The designed single axis controller consists of a dual acting pneumatic cylinder attached to the end effector of an industrial robot. The effectiveness of the force and stiffness controlled polishing system was proved through experiments --Abstract, page iii
Pneumatic motion control systems for modular robots
This thesis describes a research study in the design,
implementation, evaluation and commercialisation of
pneumatic motion control systems for modular robots. The
research programme was conducted as part of a collaborative
study, sponsored by the Science and Engineering Research
Council, between Loughborough University and Martonair (UK)
Limited.
Microprocessor based motion control strategies have been
used to produce low cost pneumatic servo-drives which can be
used for 'point-to-point' positioning of payloads. Software
based realtime control strategies have evolved which
accomplish servo-controlled positioning while compensating
for drive system non-linearities and time delays. The
application of novel compensation techniques has resulted in
a significant improvement in both the static and dynamic
performance of the drive.
A theoretical foundation is presented based on a
linearised model of a pneumatic actuator, servo-valve, and
load system. The thesis describes the design and evolution
of microprocessor based hardware and software for motion
control of pneumatic drives. A British Standards based
test-facility has allowed control strategies to be evaluated
with reference to standard performance criteria.
It is demonstrated in this research study that the dynamic
and static performance characteristics of a pneumatic motion
control system can be dramatically improved by applying
appropriate software based realtime control strategies. This
makes the application of computer controlled pneumatic
servos in manufacturing very attractive with cost
performance ratios which match or better alternative drive
technologies.
The research study has led to commercial products
(marketed by Martonair Ltd), in which realtime control
algorithms implementing these control strategy designs are
executed within a microprocessor based motion controller
A Methodology for the Design of Robotic Hands with Multiple Fingers
This paper presents a methodology that has been applied for a design process of anthropomorphic hands with multiple fingers. Biomechanical characteristics of human hand have been analysed so that ergonomic and anthropometric aspects have been used as fundamental references for obtaining grasping mechanisms. A kinematic analysis has been proposed to define the requirements for designing grasping functions. Selection of materials and actuators has been discussed too. This topic has been based on previous experiences with prototypes that have been developed at the Laboratory of Robotics and Mechatronics (LARM) of the University of Cassino. An example of the application of the proposed method has been presented for the design of a first prototype of LARM Hand
Soft Robot-Assisted Minimally Invasive Surgery and Interventions: Advances and Outlook
Since the emergence of soft robotics around two decades ago, research interest in the field has escalated at a pace. It is fuelled by the industry's appreciation of the wide range of soft materials available that can be used to create highly dexterous robots with adaptability characteristics far beyond that which can be achieved with rigid component devices. The ability, inherent in soft robots, to compliantly adapt to the environment, has significantly sparked interest from the surgical robotics community. This article provides an in-depth overview of recent progress and outlines the remaining challenges in the development of soft robotics for minimally invasive surgery
Introduction to Nuclear Propulsion: Lecture 15 - Nuclear Test Operations
The test operation of nuclear power plants, specifically nuclear rockets, bears some interesting similarities to the operation of chemical rocket tests as well as, of course, many differences. A significant feature common to both nuclear and chemical rocket tests is that all the fuel for the entire operation is loaded at the start of the test. As a direct consequence of this fact, the operation of nuclear power plants must be surrounded with adequate safety precautions, as is indeed the case in the operation of chemical rockets, A second direct consequence is that in both types of testing a very thorough and complete checkout is made before starting the test
Design, Development, and Evaluation of a Teleoperated Master-Slave Surgical System for Breast Biopsy under Continuous MRI Guidance
The goal of this project is to design and develop a teleoperated master-slave surgical system that can potentially assist the physician in performing breast biopsy with a magnetic resonance imaging (MRI) compatible robotic system. MRI provides superior soft-tissue contrast compared to other imaging modalities such as computed tomography or ultrasound and is used for both diagnostic and therapeutic procedures. The strong magnetic field and the limited space inside the MRI bore, however, restrict direct means of breast biopsy while performing real-time imaging. Therefore, current breast biopsy procedures employ a blind targeting approach based on magnetic resonance (MR) images obtained a priori. Due to possible patient involuntary motion or inaccurate insertion through the registration grid, such approach could lead to tool tip positioning errors thereby affecting diagnostic accuracy and leading to a long and painful process, if repeated procedures are required. Hence, it is desired to develop the aforementioned teleoperation system to take advantages of real-time MR imaging and avoid multiple biopsy needle insertions, improving the procedure accuracy as well as reducing the sampling errors.
The design, implementation, and evaluation of the teleoperation system is presented in this dissertation. A MRI-compatible slave robot is implemented, which consists of a 1 degree of freedom (DOF) needle driver, a 3-DOF parallel mechanism, and a 2-DOF X-Y stage. This slave robot is actuated with pneumatic cylinders through long transmission lines except the 1-DOF needle driver is actuated with a piezo motor. Pneumatic actuation through long transmission lines is then investigated using proportional pressure valves and controllers based on sliding mode control are presented. A dedicated master robot is also developed, and the kinematic map between the master and the slave robot is established. The two robots are integrated into a teleoperation system and a graphical user interface is developed to provide visual feedback to the physician. MRI experiment shows that the slave robot is MRI-compatible, and the ex vivo test shows over 85%success rate in targeting with the MRI-compatible robotic system. The success in performing in vivo animal experiments further confirm the potential of further developing the proposed robotic system for clinical applications
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