2,252 research outputs found
A Bio-Inspired Tensegrity Manipulator with Multi-DOF, Structurally Compliant Joints
Most traditional robotic mechanisms feature inelastic joints that are unable
to robustly handle large deformations and off-axis moments. As a result, the
applied loads are transferred rigidly throughout the entire structure. The
disadvantage of this approach is that the exerted leverage is magnified at each
subsequent joint possibly damaging the mechanism. In this paper, we present two
lightweight, elastic, bio-inspired tensegrity robotics arms which mitigate this
danger while improving their mechanism's functionality. Our solutions feature
modular tensegrity structures that function similarly to the human elbow and
the human shoulder when connected. Like their biological counterparts, the
proposed robotic joints are flexible and comply with unanticipated forces. Both
proposed structures have multiple passive degrees of freedom and four active
degrees of freedom (two from the shoulder and two from the elbow). The
structural advantages demonstrated by the joints in these manipulators
illustrate a solution to the fundamental issue of elegantly handling off-axis
compliance.Comment: IROS 201
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
Multi-rotor Aerial Vehicles in Physical Interactions: A Survey
Research on Multi-rotor Aerial Vehicles (MAVs) has experienced remarkable
advancements over the past two decades, propelling the field forward at an
accelerated pace. Through the implementation of motion control and the
integration of specialized mechanisms, researchers have unlocked the potential
of MAVs to perform a wide range of tasks in diverse scenarios. Notably, the
literature has highlighted the distinctive attributes of MAVs that endow them
with a competitive edge in physical interaction when compared to other robotic
systems. In this survey, we present a categorization of the various types of
physical interactions in which MAVs are involved, supported by comprehensive
case studies. We examine the approaches employed by researchers to address
different challenges using MAVs and their applications, including the
development of different types of controllers to handle uncertainties inherent
in these interactions. By conducting a thorough analysis of the strengths and
limitations associated with different methodologies, as well as engaging in
discussions about potential enhancements, this survey aims to illuminate the
path for future research focusing on MAVs with high actuation capabilities
A Novel and Accurate BiLSTM Configuration Controller for Modular Soft Robots with Module Number Adaptability
Modular soft robots have shown higher potential in sophisticated tasks than
single-module robots. However, the modular structure incurs the complexity of
accurate control and necessitates a control strategy specifically for modular
robots. In this paper, we introduce a data collection strategy and a novel and
accurate bidirectional LSTM configuration controller for modular soft robots
with module number adaptability. Such a controller can control module
configurations in robots with different module numbers. Simulation cable-driven
robots and real pneumatic robots have been included in experiments to validate
the proposed approaches, and we have proven that our controller can be
leveraged even with the increase or decrease of module number. This is the
first paper that gets inspiration from the physical structure of modular robots
and utilizes bidirectional LSTM for module number adaptability. Future work may
include a planning method that bridges the task and configuration spaces and
the integration of an online controller.Comment: 10 figures, 4 table
TOWARDS A NOVEL RESILIENT ROBOTIC SYSTEM
Resilient robotic systems are a kind of robotic system that is able to recover their original function after partial damage of the system. This is achieved by making changes on the partially damaged robot. In this dissertation study, a general robot, which makes sense by including active joints, passive joints, passive links, and passive adjustable links, was proposed in order to explore its resilience. Note that such a robot is also called an under-actuated robot. This dissertation presents the following studies.
First, a novel architecture of robots was proposed, which is characterized as under-actuated robot. The architecture enables three types of recovery strategy, namely (1) change of the robot behavior, (2) change of the robot state, and (3) change of the robot configuration. Second, a novel docking system was developed, which allows for the realization of real-time assembly and disassembly and passive joint and adjustable passive link, and this thus enables the realization of the proposed architecture. Third, an example prototype system was built to experiment the effectiveness of the proposed architecture and to demonstrate the resilient behavior of the robot. Fourth, a novel method for robot configuration synthesis was developed, which is based on the genetic algorithm (GA), to determine the goal configuration of a partially damaged robot, at which the robot can still perform its original function. The novelty of the method lies in the integration of both discrete variables such as the number of modules, type of modules, and assembly patterns between modules and the continuous variables such as the length of modules and initial location of the robot. Fifth, a GA-based method for robot reconfiguration planning and scheduling was developed to actually change the robot from its initial configuration to the goal configuration with a minimum effort (time and energy).
Two conclusions can be drawn from the above studies. First, the under-actuated robotic architecture can build a cost effective robot that can achieve the highest degree of resilience. Second, the design of the under-actuated resilient robot with the proposed docking system not only reduces the cost but also overcomes the two common actuator failures: (i) an active joint is unlocked (thus becoming a passive joint) and (ii) an active joint is locked (thus becoming an adjustable link).
There are several contributions made by this dissertation to the field of robotics. The first is the finding that an under-actuated robot can be made more resilient. In the field of robotics, the concept of the under-actuated robot is available, but it has not been considered for reconfiguration (in literature, the reconfiguration is mostly about fully actuated robots). The second is the elaboration on the concept of reconfiguration planning, scheduling, and manipulation/control. In the literature of robotics, only the concept of reconfiguration planning is precisely given but not for reconfiguration scheduling. The third is the development of the model along with its algorithm for synthesis of the goal reconfiguration, reconfiguration planning, and scheduling.
The application of the proposed under-actuated resilient robot lies in the operations in unknown or dangerous environments, for example, in rescue missions and space explorations. In these applications, replacement or repair of a damaged robot is impossible or cost-prohibited
User Intent Detection and Control of a Soft Poly-Limb
abstract: This work presents the integration of user intent detection and control in the development of the fluid-driven, wearable, and continuum, Soft Poly-Limb (SPL). The SPL utilizes the numerous traits of soft robotics to enable a novel approach to provide safe and compliant mobile manipulation assistance to healthy and impaired users. This wearable system equips the user with an additional limb made of soft materials that can be controlled to produce complex three-dimensional motion in space, like its biological counterparts with hydrostatic muscles. Similar to the elephant trunk, the SPL is able to manipulate objects using various end effectors, such as suction adhesion or a soft grasper, and can also wrap its entire length around objects for manipulation. User control of the limb is demonstrated using multiple user intent detection modalities. Further, the performance of the SPL studied by testing its capability to interact safely and closely around a user through a spatial mobility test. Finally, the limb’s ability to assist the user is explored through multitasking scenarios and pick and place tests with varying mounting locations of the arm around the user’s body. The results of these assessments demonstrate the SPL’s ability to safely interact with the user while exhibiting promising performance in assisting the user with a wide variety of tasks, in both work and general living scenarios.Dissertation/ThesisMasters Thesis Biomedical Engineering 201
Snake-Like Robots for Minimally Invasive, Single Port, and Intraluminal Surgeries
The surgical paradigm of Minimally Invasive Surgery (MIS) has been a key
driver to the adoption of robotic surgical assistance. Progress in the last
three decades has led to a gradual transition from manual laparoscopic surgery
with rigid instruments to robot-assisted surgery. In the last decade, the
increasing demand for new surgical paradigms to enable access into the anatomy
without skin incision (intraluminal surgery) or with a single skin incision
(Single Port Access surgery - SPA) has led researchers to investigate
snake-like flexible surgical devices. In this chapter, we first present an
overview of the background, motivation, and taxonomy of MIS and its newer
derivatives. Challenges of MIS and its newer derivatives (SPA and intraluminal
surgery) are outlined along with the architectures of new snake-like robots
meeting these challenges. We also examine the commercial and research surgical
platforms developed over the years, to address the specific functional
requirements and constraints imposed by operations in confined spaces. The
chapter concludes with an evaluation of open problems in surgical robotics for
intraluminal and SPA, and a look at future trends in surgical robot design that
could potentially address these unmet needs.Comment: 41 pages, 18 figures. Preprint of article published in the
Encyclopedia of Medical Robotics 2018, World Scientific Publishing Company
www.worldscientific.com/doi/abs/10.1142/9789813232266_000
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