187 research outputs found
Machine-Knitted Seamless Pneumatic Actuators for Soft Robotics: Design, Fabrication, and Characterization
Computerized machine knitting offers an attractive fabrication technology for incorporating wearable assistive devices into garments. In this work, we utilized, for the first time, whole-garment knitting techniques to manufacture a seamless fully knitted pneumatic bending actuator, which represents an advancement to existing cut-and-sew manufacturing techniques. Various machine knitting parameters were investigated to create anisotropic actuator structures, which exhibited a range of bending and extension motions when pressurized with air. The functionality of the actuator was demonstrated through integration into an assistive glove for hand grip action. The achieved curvature range when pressurizing the actuators up to 150 kPa was sufficient to grasp objects down to 3 cm in diameter and up to 125 g in weight. This manufacturing technique is rapid and scalable, paving the way for mass-production of customizable soft robotics wearables
Soft Gloves: A Review on Recent Developments in Actuation, Sensing, Control and Applications
Interest in soft gloves, both robotic and haptic, has enormously grown over the past decade, due to their inherent compliance, which makes them particularly suitable for direct interaction with the human hand. Robotic soft gloves have been developed for hand rehabilitation, for ADLs assistance, or sometimes for both. Haptic soft gloves may be applied in virtual reality (VR) applications or to give sensory feedback in combination with prostheses or to control robots. This paper presents an updated review of the state of the art of soft gloves, with a particular focus on actuation, sensing, and control, combined with a detailed analysis of the devices according to their application field. The review is organized on two levels: a prospective review allows the highlighting of the main trends in soft gloves development and applications, and an analytical review performs an in-depth analysis of the technical solutions developed and implemented in the revised scientific research. Additional minor evaluations integrate the analysis, such as a synthetic investigation of the main results in the clinical studies and trials referred in literature which involve soft gloves
The Research on Soft Pneumatic Actuators in Italy: Design Solutions and Applications
Interest in soft actuators has increased enormously in the last 10 years. Thanks to their compliance and flexibility, they are suitable to be employed to actuate devices that must safely interact with humans or delicate objects or to actuate bio-inspired robots able to move in hostile environments. This paper reviews the research on soft pneumatic actuators conducted in Italy, focusing on mechanical design, analytical modeling, and possible application. A classification based on the geometry is proposed, since a wide set of architectures and manufacturing solutions are available. This aspect is confirmed by the extent of scenarios in which researchers take advantage of such systems’ improved flexibility and functionality. Several applications regarding bio-robotics, bioengineering, wearable devices, and more are presented and discussed
A fabric-based soft hand exoskeleton for assistance: the ExHand Exoskeleton
INTRODUCTION: The rise of soft robotics has driven the development of devices for assistance in activities of daily living (ADL). Likewise, different types of actuation have been developed for safer human interaction. Recently, textile-based pneumatic actuation has been introduced in hand exoskeletons for features such as biocompatibility, flexibility, and durability. These devices have demonstrated their potential use in assisting ADLs, such as the degrees of freedom assisted, the force exerted, or the inclusion of sensors. However, performing ADLs requires the use of different objects, so exoskeletons must provide the ability to grasp and maintain stable contact with a variety of objects to lead to the successful development of ADLs. Although textile-based exoskeletons have demonstrated significant advancements, the ability of these devices to maintain stable contact with a variety of objects commonly used in ADLs has yet to be fully evaluated. MATERIALS AND METHODS: This paper presents the development and experimental validation in healthy users of a fabric-based soft hand exoskeleton through a grasping performance test using The Anthropomorphic Hand Assessment Protocol (AHAP), which assesses eight types of grasping with 24 objects of different shapes, sizes, textures, weights, and rigidities, and two standardized tests used in the rehabilitation processes of post- stroke patients. RESULTS AND DISCUSSION: A total of 10 healthy users (45.50 ± 14.93 years old) participated in this study. The results indicate that the device can assist in developing ADLs by evaluating the eight types of grasps of the AHAP. A score of 95.76 ± 2.90% out of 100% was obtained for the Maintaining Score, indicating that the ExHand Exoskeleton can maintain stable contact with various daily living objects. In addition, the results of the user satisfaction questionnaire indicated a positive mean score of 4.27 ± 0.34 on a Likert scale ranging from 1 to 5
MOSAR: A Soft-Assistive Mobilizer for Upper Limb Active Use and Rehabilitation
In this study, a soft assisted mobilizer called MOSAR from (Mobilizador Suave de Asistencia y Rehabilitación) for upper limb rehabilitation was developed for a 11 years old child with
right paretic side. The mobilizer provides a new therapeutic approach to augment his upper limb active use and rehabilitation, by means of exerting elbow (flexion-extension), forearm (pronation-supination) and (flexion-extension along with ulnar-radial deviations) at the wrist.
Preliminarily, the design concept of the soft mobilizer was developed through Reverse Engineering of his upper limb: first casting model, silicone model, and later computational
model were obtained by 3D scan, which was the parameterized reference for MOSAR development. Then, the manufacture of fabric inflatable soft actuators for driving the MOSAR system were carried out. Lastly, a law close loop control for the inflation-deflation process was implemented to validate FISAs performance. The results demonstrated the feasibility and
effectiveness of the FISAs for being a functional tool for upper limb rehabilitation protocols by achieving those previous target motions similar to the range of motion (ROM) of a healthy
person or being used in other applications
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
Fabric-based eversion type soft actuators for robotic grasping applications
Humans have managed to simplify their lives by using robots to automate dull and repetitive tasks. Traditional robots have been very helpful in this respect, but in certain applications, the complexity of manufacturing and the requisite control strategies have rendered these systems inadequate. The concept of robots made of soft materials has increasingly been explored and a new avenue of research has opened up within the robotics community. In terms of construction, robots made of soft and flexible materials have several advantages over their rigid-bodied counterparts, among them simple design, simple control mechanisms, inexpensive constituent materials and the fact that they can be easily integrated into existing systems. Soft grippers in particular have been the subject of extensive research and we have witnessed significant development in terms of attributes like grasping, payload and sensing methodologies. Progress has been enhanced by the development of new materials used in the construction of actuators or end effectors of the grippers. The use of lightweight, non-stretch fabrics is a relatively new concept but initial studies have demonstrated their effectiveness in grasping applications. This thesis sets out a comparative study of popular gripping systems, focusing on the advantages of using fabrics in the construction of soft grippers. Multiple designs for fabric based finger like actuators, each addressing the drawbacks of the preceding design, are discussed along with the experimental evaluation of each design. A novel gripping mechanism in which the fingers of the gripper grow lengthwise from the tip (evert) to access and grasp the object is also presented. Large-scale fabric based eversion robots have been constructed to access environments with restricted access and for monitoring purposes. An experimental evaluation of the eversion capable finger is also presented, outlining important attributes such as payload, bending and force capability of the designed finger. An optical fibre based sensing methodology is also presented, capable of measuring the bending behaviour in soft actuators. The proposed sensor can be configured to sense bending angles, as well as the contact forces along different points along the length of the actuators
A Retrofit Sensing Strategy for Soft Fluidic Robots
Soft robots are intrinsically capable of adapting to different environments
by changing their shape in response to interaction forces with the environment.
However, sensing and feedback are still required for higher level decisions and
autonomy. Most sensing technologies developed for soft robots involve the
integration of separate sensing elements in soft actuators, which presents a
considerable challenge for both the fabrication and robustness of soft robots
due to the interface between hard and soft components and the complexity of the
assembly. To circumvent this, here we present a versatile sensing strategy that
can be retrofitted to existing soft fluidic devices without the need for design
changes. We achieve this by measuring the fluidic input that is required to
activate a soft actuator and relating this input to its deformed state during
interaction with the environment. We demonstrate the versatility of our sensing
strategy by tactile sensing of the size, shape, surface roughness and stiffness
of objects. Moreover, we demonstrate our approach by retrofitting it to a range
of existing pneumatic soft actuators and grippers powered by positive and
negative pressure. Finally, we show the robustness of our fluidic sensing
strategy in closed-loop control of a soft gripper for practical applications
such as sorting and fruit picking. Based on these results, we conclude that as
long as the interaction of the actuator with the environment results in a shape
change of the interval volume, soft fluidic actuators require no embedded
sensors and design modifications to implement sensing. We believe that the
relative simplicity, versatility, broad applicability and robustness of our
sensing strategy will catalyze new functionalities in soft interactive devices
and systems, thereby accelerating the use of soft robotics in real world
applications
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