8,064 research outputs found
Origami-inspired soft twisting actuator
Soft actuators have shown great advantages in compliance and morphology
matched for manipulation of delicate objects and inspection in a confined
space. There is an unmet need for a soft actuator that can provide torsional
motion to e.g. enlarge working space and increase degrees of freedom. Towards
this goal, we present origami-inspired soft pneumatic actuators (OSPAs) made
from silicone. The prototype can output a rotation of more than one revolution
(up to 435{\deg}), more significant than its counterparts. Its rotation ratio
(=rotation angle/ aspect ratio) is more than 136{\deg}, about twice the largest
one in other literature. We describe the design and fabrication method, build
the analytical model and simulation model, and analyze and optimize the
parameters. Finally, we demonstrate the potentially extensive utility of the
OSPAs through their integration into a gripper capable of simultaneously
grasping and lifting fragile or flat objects, a versatile robot arm capable of
picking and placing items at the right angle with the twisting actuators, and a
soft snake robot capable of changing attitude and directions by torsion of the
twisting actuators.Comment: 9 figures. Soft Robotics (2022
A review of the effectiveness of lower limb orthoses used in cerebral palsy
To produce this review, a systematic literature search was conducted for relevant articles published in the period between the date of the previous ISPO consensus conference report on cerebral palsy (1994) and April 2008. The search terms were 'cerebral and pals* (palsy, palsies), 'hemiplegia', 'diplegia', 'orthos*' (orthoses, orthosis) orthot* (orthotic, orthotics), brace or AFO
Design of a Multimodal Fingertip Sensor for Dynamic Manipulation
We introduce a spherical fingertip sensor for dynamic manipulation. It is
based on barometric pressure and time-of-flight proximity sensors and is
low-latency, compact, and physically robust. The sensor uses a trained neural
network to estimate the contact location and three-axis contact forces based on
data from the pressure sensors, which are embedded within the sensor's sphere
of polyurethane rubber. The time-of-flight sensors face in three different
outward directions, and an integrated microcontroller samples each of the
individual sensors at up to 200 Hz. To quantify the effect of system latency on
dynamic manipulation performance, we develop and analyze a metric called the
collision impulse ratio and characterize the end-to-end latency of our new
sensor. We also present experimental demonstrations with the sensor, including
measuring contact transitions, performing coarse mapping, maintaining a contact
force with a moving object, and reacting to avoid collisions.Comment: 6 pages, 2 pages of references, supplementary video at
https://youtu.be/HGSdcW_aans. Submitted to ICRA 202
Toward Dynamic Manipulation of Flexible Objects by High-Speed Robot System: From Static to Dynamic
This chapter explains dynamic manipulation of flexible objects, where the target objects to be manipulated include rope, ribbon, cloth, pizza dough, and so on. Previously, flexible object manipulation has been performed in a static or quasi-static state. Therefore, the manipulation time becomes long, and the efficiency of the manipulation is not considered to be sufficient. In order to solve these problems, we propose a novel control strategy and motion planning for achieving flexible object manipulation at high speed. The proposed strategy simplifies the flexible object dynamics. Moreover, we implemented a high-speed vision system and high-speed image processing to improve the success rate by manipulating the robot trajectory. By using this strategy, motion planning, and high-speed visual feedback, we demonstrated several tasks, including dynamic manipulation and knotting of a rope, generating a ribbon shape, dynamic folding of cloth, rope insertion, and pizza dough rotation, and we show experimental results obtained by using the high-speed robot system
Graphene-based flexible sensors towards electronic wearables
Flexible electronics and wearable devices have attracted considerable attention because they produce mechanical liberty, in terms of flexibility and stretchability that can enable the possibility of a wide range of new applications. The term âwearable electronicsâ can be used to define devices that can be worn or mated with the sensed surface to continuously monitor signals without limitations on mechanical deformability of the devices and electronic performance of the functional materials. The use of polymeric substrates or other nonconventional substrates as base materials brings novel functionalities to sensors and other electronic devices in terms of being flexible and light weight. Conductive nanomaterials, such as carbon nanotubes and graphene have been utilized as functional materials for flexible electronics and wearable devices. Graphene has specifically been considered for producing next-generation sensors due to its impressive electrical and mechanical properties and a result, incorporation of flexible substrates and graphene-based nanomaterials has been widely utilized to form versatile flexible sensors and other wearable devices through use of different fabrication processes.
Creation of a large-scale, simple, high-resolution and cost-effective technique that overcomes fabrication limitations and supports production of flexible graphene-based sensors with high flexibility and stretch ability is highly demanding. Soft lithography can be merged with a mechanical exfoliation process using adhesive tape followed by transfer printing to form a graphene sensor on a desired final substrate. In situ microfluidic casting of graphene into channels is another promising platform driving the rapid development of flexible graphene sensors and wearable devices with a wide dynamic detection range. Selective coating of graphene-based nanomaterials (e.g. graphene oxide (GO)) on flexible electrode tapes can, because of its flexibility and adhesive features, be used to track relative humidity (RH) variations at the surface of target surfaces. This thesis describes the design and development of flexible and wearable strain, pressure and humidity sensors based on a novel tape-based cost-effective patterning and transferring technique, an in situ microfluidic casting method, and a novel selective coating technique for graphene-based nanomaterials.
First of all, we present a tape-based graphene patterning and transferring approach to production of graphene sensors on elastomeric substrates and adhesive tapes. The method utilizes the work of adhesion at the interface between two contacting materials as determined by their surface energies to pattern graphene on PDMS substrate and transfer it onto a target tape. We have achieved patterning and transferring method with the features of high pattern spatial resolution, thickness control, and process simplicity with respect to functional materials and pattern geometries. We have demonstrated the usage of flexible graphene sensors on tape to realize interaction with structures, humans, and plants for real-time monitoring of important signals.
Secondly, we present a helical spring-like piezo resistive graphene sensor formed within a microfluidic channel using a unique and easy in situ microfluidic casting method. Because of its helical shape, the sensor exhibits a wide dynamic detection range as well as mechanical flexibility and stretch ability.
Finally, we present a flexible GO-based RH sensor on an adhesive polyimide thin film realized by selectively coating and patterning GO at the surface of Au Interdigitated electrodes (IDEs) and subsequently peeling the device from a temporary PDMS film. Real-time monitoring of the water movement inside the plant has been demonstrated by installing GO-based RH sensor at the surfaces of different plant leaves
Occupational Communication Modes and Symbols: A Study of the Non-Verbal Perspective of Artisanal Marine Fishing Practices in Ghana.
In Ghana, virtually the entire coastline is strewn with marine fishing. Artisanal marine fishing however dominates the industry. The trade is essentially informal in nature. The communication pattern in this occupation is quite unique. Various modes and symbols, both tangible and intangible, serve as communication sources and media of information in the conduct of daily business. This study describes and records the nonverbal modes and symbols of communication in artisanal marine fishing in Ghana. It examines whether there are differences in the observed nonverbal communicative patterns among the sampled communities, and also assesses how time and modernity have affected the kind of communication pattern employed. It is qualitative, and employs a multiple case design that purposively samples three communities in the Central Region of Ghana. It is grounded on Morrisâs semiotics on signs, behaviour and interaction, and Wilsonâs taxonomy of non-verbal perspective of indigenous communication. Findings show that the stars, winds, waves, cultural events, among others communicate relevant messages to the fisherman. Differences in the nonverbal communicative pattern among the sampled communities are rather minimal, and attributed to variations in local culture. Technological advancement is also gradually catching up on the otherwise traditional occupation. Keywords: Artisanal marine fishing, Non-verbal communication, Culture, Traditional media, Object
Deep Model Predictive Variable Impedance Control
The capability to adapt compliance by varying muscle stiffness is crucial for
dexterous manipulation skills in humans. Incorporating compliance in robot
motor control is crucial to performing real-world force interaction tasks with
human-level dexterity. This work presents a Deep Model Predictive Variable
Impedance Controller for compliant robotic manipulation which combines Variable
Impedance Control with Model Predictive Control (MPC). A generalized Cartesian
impedance model of a robot manipulator is learned using an exploration strategy
maximizing the information gain. This model is used within an MPC framework to
adapt the impedance parameters of a low-level variable impedance controller to
achieve the desired compliance behavior for different manipulation tasks
without any retraining or finetuning. The deep Model Predictive Variable
Impedance Control approach is evaluated using a Franka Emika Panda robotic
manipulator operating on different manipulation tasks in simulations and real
experiments. The proposed approach was compared with model-free and model-based
reinforcement approaches in variable impedance control for transferability
between tasks and performance.Comment: Preprint submitted to the journal of robotics and autonomous system
Evaluating Effects of Character Appearance on Ownership and Learning in Virtual Applications
Virtual applications are now a dominant commercial and social platform. Sixty-seven percent of households own a gaming device, and eighty-one percent of the United States population has a social media profile. Now, virtual reality appears to be the next technological frontier that will take over mainstream markets. New, low-cost devices for virtual reality or mixed reality such as the Oculus Rift, Sony\u27s PlayStation VR, or Samsung\u27s Gear VR are already available or have been announced and might even outperform previous high-cost systems. With the prevalence of this technology, it is important to know how it influences us. One common factor that has remained popular in virtual applications throughout its evolution are characters. How does the appearance of characters affect us in virtual applications and virtual reality? Towards understanding these effects, this research presents findings on results when character model appearance is altered in an educational application and in self-representative avatars. Results from our experiments show that allowing character customization in an educational software results in higher learning outcomes for participants. We also find that when controlling self-avatars, some participants can feel that they own any virtual hand model given to them in virtual reality. In addition, we find that participants generally feel the strongest ownership for virtual hands that appear human-like. Finally, we find that participants experience stronger feelings of ownership and realism when they are able to control virtual hands directly rather than with a hand-held device, and that the virtual reality task must first be considered to determine which modality and hand size are the most applicable. These results contribute to knowledge for how to best create characters for users in virtual applications and environments
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