Soft Pneumatic Actuators for Rehabilitation

Pneumatic artificial muscles are pneumatic devices with practical and various applications as common actuators. They, as human muscles, work in agonistic-antagonistic way, giving a traction force only when supplied by compressed air. The state of the art of soft pneumatic actuators is here analyzed: different models of pneumatic muscles are considered and evolution lines are presented. Then, the use of Pneumatic Muscles (PAM) in rehabilitation apparatus is described and the general characteristics required in different applications are considered, analyzing the use of proper soft actuators with various technical properties. Therefore, research activity carried out in the Department of Mechanical and Aerospace Engineering in the field of soft and textile actuators is presented here. In particular, pneumatic textile muscles useful for active suits design are described. These components are made of a tubular structure, with an inner layer of latex coated with a deformable outer fabric sewn along the edge. In order to increase pneumatic muscles forces and contractions Braided Pneumatic Muscles are studied. In this paper, new prototypes are presented, based on a fabric construction and various kinds of geometry. Pressure-force-deformation tests results are carried out and analyzed. These actuators are useful for rehabilitation applications. In order to reproduce the whole upper limb movements, new kind of soft actuators are studied, based on the same principle of planar membranes deformation. As an example, the bellows muscle model and worm muscle model are developed and described. In both cases, wide deformations are expected. Another issue for soft actuators is the pressure therapy. Some textile sleeve prototypes developed for massage therapy on patients suffering of lymph edema are analyzed. Different types of fabric and assembly techniques have been tested. In general, these Pressure Soft Actuators are useful for upper/lower limbs treatments, according to medical requirements. In particular devices useful for arms massage treatments are considered. Finally some applications are considered

Soft pneumatic devices for blood circulation improvement

The research activity I am presenting in this thesis lies within the framework of a cooperation between the University of Cagliari (Applied Mechanics and Robotics lab, headed by professor Andrea Manuello Bertetto, and the research group of physicians referencing to professor Alberto Concu at the Laboratory of Sports Physiology, Department of Medical Sciences), and the Polytechnic of Turin (professor Carlo Ferraresi and his equipe at the Group of Automation and Robotics, Department of Mechanical and Aerospace Engineering) This research was also funded by the Italian Ministry of Research (MIUR – PRIN 2009). My activity has been mainly carried on at the Department of Mechanics, Robotics lab under the supervision of prof. Manuello; I have also spent one year at the Control Lab of the School of Electrical Engineering at Aalto University (Helsinki, Finland). The tests on the patients were taken at the Laboratory of Sports Physiology, Cagliari. I will be describing the design, development and testing of some soft pneumatic flexible devices meant to apply an intermittent massage and to restore blood circulation in lower limbs in order to improve cardiac output and wellness in general. The choice of the actuators, as well as the pneumatic circuits and air distribution system and PLC control patterns will be outlined. The trial run of the devices have been field--‐tested as soon a prototype was ready, so as to tune its features step--‐by--‐ step. I am also giving a characterization of a commercial thin force sensor after briefly reviewing some other type of thin pressure transducer. It has been used to gauge the contact pressure between the actuator and the subject’s skin in order to correlate the level of discomfort to the supply pressure, and to feed this value back to regulate the supply air flow. In order for the massage to be still effective without causing pain or distress or any cutoff to the blood flow, some control objective have been set, consisting in the regulation of the contact force so that it comes to the constant set point smoothly and its value holds constant until unloading occurs. The targets of such mechatronic devices range from paraplegic patients lacking of muscle tone because of their spinal cord damage, to elite endurance athletes needing a circulation booster when resting from practicing after serious injuries leading to bed rest. Encouraging results have been attained for both these two categories, based on the monitored hemodynamic variables

Robotics in Dentistry : A Narrative Review

Background: Robotics is progressing rapidly. The aim of this study was to provide a comprehensive overview of the basic and applied research status of robotics in dentistry and discusses its development and application prospects in several major professional fields of dentistry. Methods: A literature search was conducted on databases: MEDLINE, IEEE and Cochrane Library, using MeSH terms: [“robotics” and “dentistry”]. Result: Forty-nine articles were eventually selected according to certain inclusion criteria. There were 12 studies on prosthodontics, reaching 24%; 11 studies were on dental implantology, accounting for 23%. Scholars from China published the most articles, followed by Japan and the United States. The number of articles published between 2011 and 2015 was the largest. Conclusions: With the advancement of science and technology, the applications of robots in dental medicine has promoted the development of intelligent, precise, and minimally invasive dental treatments. Currently, robots are used in basic and applied research in various specialized fields of dentistry. Automatic tooth-crown-preparation robots, tooth-arrangement robots, drilling robots, and orthodontic archwire-bending robots that meet clinical requirements have been developed. We believe that in the near future, robots will change the existing dental treatment model and guide new directions for further development

Modeling and Experimental Study of a Novel Multi-DOF Parallel Soft Robot

In view of the demand for flexible drive and large load of the soft robot in the practical application, a novel type of flexible-actuated multi-degree-of-freedom (multi-DOF) parallel soft robot is designed. The proposed robot in parallel combination of three groups of flexible-actuated elements (FAEs) realizes large load by increasing the bearing area at the connection between flexible-actuated units (FAUs). In order to improve the driving flexibility, the multi-layer FAU is used to drive independently in parallel so as to realize omnidirectional bending movement by pneumatic drive. With the coupled analysis in terms of motion and force, the mapping model of kinematic attitude parameters and the external load force with output air pressure value is established. Finally, an experimental prototype is developed and an experimental test platform is built. Then, the comparison among the experimental data, simulation results and theoretical results verifies the capability of multi-DOF omnidirectional movement and flexible-actuated large load

Design, Modeling, and Fabrication of a Massage Neck Support Using Soft Robot Mechanism

The purpose of this research is to design and fabricate a neck support with massage function by applying a soft robot mechanism. Soft robot is fabricated by soft materials and can achieve certain shape deformation under actuations. The application of soft robot in the neck support enables its ability for individual adjustment and even massages function to improve comfort and alleviate fatigue. It has much lighter weight compared to those made of hard materials. In addition, applying the soft robot mechanism also allows lower manufacturing cost. The prototype design was validate by finite element analysis prior the actual fabrication to determine the feasibility for the design concept. A down scale prototype was fabricated first for practice and it was tested for concept validation. The full scale prototype was fabricated but it is not functional due to errors from manufacturing process. Future work will be focused on re-fabrication of full scale prototype and optimization for the neck support.No embargoAcademic Major: Mechanical Engineerin

A Variable Impedance Scheme Based on Power-Shaping Signals and Partial Knowledge of Link-Side Dynamics for Flexible-Joint Robot Interaction and Tracking Control

This article proposes a novel scheme - based on power-shaping control (PSC) - that can endow flexible-joint robots with both tracking, and interactional, capabilities. In virtue of relying upon the PSC method, this approach entails modest modeling requirements restricted to computation of the gravitational torque vector, and motor-side dynamics terms (typically available in manufacturer datasheets). Hence, it distinguishes itself by obviating the need for calculation of computationally cumbersome link-side dynamics elements, such as the Coriolis and link inertia matrices. In contrast to analogous schemes, the highest order term required by the proposed design is the third derivative of the motor position vector; it therefore avoids the usage of link-jerk feedback that can be detrimental to interactional performance. Moreover, the propounded framework enables utilisation of noncollocated feedback for enhanced tracking accuracy, as well as variable impedance control for interactional performance augmentation. The aforesaid features are effectuated without any reliance on coordinate transformations; thus, the original dynamical model's structure remains immutable throughout. Also, the proposed design's complexity is dependent solely on the gravitational torque vector's dimension (i.e., not on the link inertia or Coriolis terms). Experimental results involving a flexible-joint robot, namely the Rethink Robotics Baxter, corroborate the theoretical analyses, in addition to demonstrating that interactional performance improvements can be achieved via the proposed methodology.</p

A soft, synergy-based robotic glove for grasping assistance

This paper presents a soft, tendon-driven, robotic glove designed to augment grasp capability and provide rehabilitation assistance for postspinal cord injury patients. The basis of the design is an underactuation approach utilizing postural synergies of the hand to support a large variety of grasps with a single actuator. The glove is lightweight, easy to don, and generates sufficient hand closing force to assist with activities of daily living. Device efficiency was examined through a characterization of the power transmission elements, and output force production was observed to be linear in both cylindrical and pinch grasp configurations. We further show that, as a result of the synergy-inspired actuation strategy, the glove only slightly alters the distribution of forces across the fingers, compared to a natural, unassisted grasping pattern. Finally, a preliminary case study was conducted using a participant suffering from an incomplete spinal cord injury (C7). It was found that through the use of the glove, the participant was able to achieve a 50% performance improvement (from four to six blocks) in a standard Box and Block test