Soft Limb Research Articles

Soft Gripping Fingers Made of Multi-Stacked Dielectric Elastomer Actuators with Backbone Strategy.

Soft grippers, a rapidly growing subfield of soft robotics, utilize compliant and flexible materials capable of conforming to various shapes. This feature enables them to exert gentle yet, if required, strong gripping forces. In this study, we elaborate on the material selection and fabrication process of gripping fingers based on the dielectric elastomer actuation technique. We study the effects of mixing the silicone elastomer with a silicone thinner on the performance of the actuators. Inspired by nature, where the motion of end-effectors such as soft limbs or fingers is, in many cases, directed by a stiff skeleton, we utilize backbones for translating the planar actuation into a bending motion. Thus, the finger does not need any rigid frame or pre-stretch, as in many other DEA approaches. The idea and function of the backbone strategy are demonstrated by finite element method simulations with COMSOL Multiphysics® 6.5. The paper describes the full methodology from material choice and characterization, design, and simulation to characterization to enable future developments based on our approach. Finally, we present the performance of these actuators in a gripper demonstrator setup. The developed actuators bend up to 68.3° against gravity, and the gripper fingers hold up to 10.3 g against gravity under an actuation voltage of 8 kV.

An Underwater Biomimetic Robot that can Swim, Bipedal Walk and Grasp

In developing and exploring extreme and harsh underwater environments, underwater robots can effectively replace humans to complete tasks. To meet the requirements of underwater flexible motion and comprehensive subsea operation, a novel octopus-inspired robot with eight soft limbs was designed and developed. This robot possesses the capabilities of underwater bipedal walking, multi-arm swimming, and grasping objects. To closely interact with the underwater seabed environment and minimize disturbance, the robot employs a cable-driven flexible arm for its walking in underwater floor through a bipedal walking mode. The multi-arm swimming offers a means of three-dimensional spatial movement, allowing the robot to swiftly explore and navigate over large areas, thereby enhancing its flexibility. Furthermore, the robot’s walking arm enables it to grasp and transport objects underwater, thereby enhancing its practicality in underwater environments. A simplified motion models and gait generation strategies were proposed for two modes of robot locomotion: swimming and walking, inspired by the movement characteristics of octopus-inspired multi-arm swimming and bipedal walking. Through experimental verification, the robot’s average speed of underwater bipedal walking reaches 7.26 cm/s, while the horizontal movement speed for multi-arm swimming is 8.6 cm/s.

Background Material Identification Using a Soft Robot

Soft robotics is an emerging technology that provides robots with the ability to adapt to the environment and safely interact with it. Here, the ability of these robots to identify the surface of interaction is critical for grasping and locomotion tasks. This paper describes the capability of a four-limb soft robot that can identify background materials through the collection of reflection coefficients using an embedded antenna and machine learning techniques. The material of a soft-limb robot was characterized in terms of the relative permittivity and the loss tangent for the design of an antenna to collect reflection coefficients. A slot antenna was designed and embedded into a soft limb in order to extract five features in reflection coefficients including the resonant frequency, −3 dB bandwidth taken from the lowest S11, the value of the lowest S11, −3 dB bandwidth taken from the highest S11, and the number of resonant frequencies. A soft robot with the embedded antenna was tested on nine different background materials in an attempt to identify surrounding terrain information and a better robotic operation. The tested background materials included concrete, fabric, grass, gravel, metal, mulch, soil, water, and wood. The results showed that the robot was capable of distinguishing among the nine different materials with an average accuracy of 93.3% for the nine background materials using a bagged decision-tree-based ensemble method algorithm.

Development of an inchworm-like soft pipe robot for detection

Pipe robots have been gradually applied to regularly detect drainage pipelines in building to ensure drainage system operating smoothly. However, mostly existing pipe robots hardly pass through various pipelines for insufficient flexibility of rigid mechanism and clumsy movement. Inspired by the soft limbs and efficient motion mode of inchworm, a soft pipe robot is developed to smoothly traverse these pipelines by reasonably optimizing modular actuators based on deformation analysis. By constructing a uniform mechanical model considering varying gravity load, the mechanical equilibrium relations during robot worming are established to accurately calculate inflating/deflating volume of actuators. Integrating inflating/deflating time calculating method for different working-state actuators, an efficient motion control workflow is developed to coordinately control each actuator to inflate/deflate orderly with the cooperation of control system. Experiment results show that the developed robot adopting proposed motion control workflow can move stably in horizontal, vertical, inclined, varying diameter and continuous curved pipelines.

In-Situ Sensing and Dynamics Predictions for Electrothermally-Actuated Soft Robot Limbs.

Untethered soft robots that locomote using electrothermally-responsive materials like shape memory alloy (SMA) face challenging design constraints for sensing actuator states. At the same time, modeling of actuator behaviors faces steep challenges, even with available sensor data, due to complex electrical-thermal-mechanical interactions and hysteresis. This article proposes a framework for in-situ sensing and dynamics modeling of actuator states, particularly temperature of SMA wires, which is used to predict robot motions. A planar soft limb is developed, actuated by a pair of SMA coils, that includes compact and robust sensors for temperature and angular deflection. Data from these sensors are used to train a neural network-based on the long short-term memory (LSTM) architecture to model both unidirectional (single SMA) and bidirectional (both SMAs) motion. Predictions from the model demonstrate that data from the temperature sensor, combined with control inputs, allow for dynamics predictions over extraordinarily long open-loop timescales (10 min) with little drift. Prediction errors are on the order of the soft deflection sensor’s accuracy. This architecture allows for compact designs of electrothermally-actuated soft robots that include sensing sufficient for motion predictions, helping to bring these robots into practical application.

Robust Control of a Multi-Axis Shape Memory Alloy-Driven Soft Manipulator

Control of soft robotic manipulators remains a challenge for designs with advanced capabilities and novel actuation. Two significant limitations are multi-axis, three-dimensional motion of soft bodies alongside actuator dynamics and constraints, both of which are present in shape-memory-alloy (SMA)-powered soft robots. This article addresses both concerns with a robust feedback control scheme, demonstrating state tracking control for a soft robot manipulator of this type. Our controller uses a static beam bending model to approximate the soft limb as an LTI system, alongside a singular-value-decomposition compensator approach to decouple the multi-axial motion and an anti-windup element for the actuator saturation. We prove stability and verify robustness of our controller, with robustness intended to account for the unmodeled dynamics. Our implementation is verified in hardware trajectory tracking tests of a soft SMA-powered limb with accurate, promising results for future multi-limbed robots.

Soft-Tentacle Gripper for Pipe Crawling to Inspect Industrial Facilities Using UAVs

This paper presents a crawling mechanism using a soft-tentacle gripper integrated into an unmanned aerial vehicle for pipe inspection in industrial environments. The objective was to allow the aerial robot to perch and crawl along the pipe, minimizing the energy consumption, and allowing to perform contact inspection. This paper introduces the design of the soft limbs of the gripper and also the internal mechanism that allows movement along pipes. Several tests have been carried out to ensure the grasping capability on the pipe and the performance and reliability of the developed system. This paper shows the complete development of the system using additive manufacturing techniques and includes the results of experiments performed in realistic environments.

Soft Electrically Actuated Quadruped (SEAQ)—Integrating a Flex Circuit Board and Elastomeric Limbs for Versatile Mobility

Like their natural mammalian and reptilian counterparts, legged soft robots require robust walking dynamics and untethered functionality in order to swiftly maneuver through unstructured environments. Progress in this domain requires careful selection of soft limb actuators and integration of power and control electronics into a soft robotics platform capable of biologically relevant locomotion speeds without dependency on external hardware. We demonstrate this with an untethered soft palm–sized, 25 g soft electrically actuated quadruped, which is capable of crawling at a maximum speed of 0.56 body length per second (3.2 cm/s), and making 90° turns in two complete gait cycles (∼5 s). The robot is composed of a flexible printed circuit board and electrically powered soft limbs that contain shape memory alloy (SMA) wires inserted between pre–stretched layers of a soft, thermally conductive elastomer. Its versatile mobility and robust dynamics are demonstrated by its ability to walk on a variety of surfaces—including inclines, rocky, and granular surfaces, and steps that are over half the robot height—and maintain continuous forward locomotion through confined space or after being dropped from an elevated height. In addition to these locomotion studies, we perform an experimental study on the blocking force of a single actuator to provide independent support for the feasibility of untethered soft robot walking with SMA–based actuation.

Nomograms Predict Cancer-Specific and Overall Survival of Patients With Primary Limb Leiomyosarcoma.

To date, there have been no data to predict the survival of patients with leiomyosarcoma from soft limb tissue because of the rarity of this disease. Nomograms have been widely applied in clinical oncology to precisely predict the survival of individual patients. This was a retrospective study to construct and validate nomograms to predict the cancer-specific survival (CSS) and overall survival (OS) of patients with primary limb leiomyosarcoma (PL-LMS). A total of 1,208 patients with LMS from limb soft tissue were collected from the Surveillance, Epidemiology, and End Results database from 1975 to 2015. We identified independent prognostic factors using univariate and multivariate Cox analyses. These prognostic factors were then included in the nomograms to predict 3- and 5-year CSS and OS rates. Finally, we validated the nomograms internally and externally. A total of 1208 patients were collected and divided into validation (N = 604) and training (N = 604) groups. Age, race, grade, tumor size, stage, and surgical types were demonstrated as independent prognostic factors for CSS and OS (all p < 0.05) and further used to construct the nomograms. The concordance index (C-index) for CSS was 0.857 for internal validation and 0.727 for external validation. The C-index for OS and CSS both demonstrated that the nomogram prediction agreed perfectly with actual survival. We developed nomograms to predict CSS and OS in PL-LMS patients and can benefit from using them to identify patients' mortality risk and make more precise assessments regarding survival. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1649-1657, 2019.

Challenge in Management of Aggressive Clients in Psychiatric Setting: Development of Four-Point Physical Restraints

Introduction: The use of physical restraints is a very common procedure in psychiatric setting from the beginning of psychiatry as a branch of medicine. Any measure that keep someone under control is called a restraint. Four-point physical restraints are required for managing clients with mental illness. Material and Method: The objective of the project was to develop a safe and secure soft limb restraints for aggressive clients. A set of soft limb restraints (two each for upper and lower limbs) was developed along with user guidelines. High quality narrow woven fabric material was selected for preparing the restraints. The restraints were tested in 5 psychiatric hospitals. A 12 item checklist was developed and validated for assessing the user friendliness of the restraints. Necessary modifications were made based on the feedback given by the nurses who tested it. Results: All the nurses (100%) reported that the developed restraints were easy to apply, easy to remove and met the safety of the clients. Conclusion: The restraints developed was found to be more safe and operable as compared to other commercially available restraints.

A Compliant Telescopic Limb with Anisotropic Stiffness

Soft limbs with anisotropic stiffness are common in nature and enable animals to solve a variety of tasks, including locomotion and manipulation. This mixture of hardness and softness enables animals to efficiently control the unpredictable contact forces that occur while performing such tasks. A challenge for soft robotics is to create artificial limbs that mimic natural mixtures of hardness and softness for use as a building block for soft, adaptable robots. This article presents the design of a novel pneumatic limb module with adjustable length and anisotropic stiffness. The artificial limb is designed with a rigid telescopic endoskeleton inside a rubber bellow, which we show is able to resist buckling, while remaining externally soft. Finally, we present the design of a hexapod walker based on the limb units.

Les verbes περιπατει̃ν et φέρειν dans le Livre VII des Lois de Platon : la promenade et le portage dans la formation du jeune enfant

The verbs περιπατει̃ν and φέρειν in book VII of Plato's Laws: walk and carriage in the development of the young child. In the 789th passage of his Laws Plato uses the verbs peripatein and ferein when referring to the respective activities of pregnant women and nurses. The study of these two verbs is centered on the positive effects of walk and carrying on embryos and newborns. Pregnant women are required to walk because this helps to ‘ mould’ the soft body of the future baby. Such movements should control the moods and frights of the fetus. Plato seems to be repeating Hippocrates’ theses on the contribution of walking to the physical and sanitary formation of the human body. However, what makes this philosopher’s approach a peculiar one lies in his advocating pregnant women’s walking with a view to having the children in the womb benefit from it. Child-carrying which is imposed upon the sturdy nurses of the ideal city in Plato’s Laws is a physical ordeal that protects from deformity the young and soft limbs of children under three. Finally, in both prenatal and postnatal periods, Plato has strongly advocated pregnant women’s walking and child-carrying because of the physical and psychological advantages infants derive from them. As a matter of fact, the eugenics that is extolled by Plato in the ideal city of his Laws is the main prop of the pedagogical orientation he is advocating.

Bone Mineral Analysis through Dual Energy X-Ray Absorptiometry in Laboratory Animals

To determine how to eliminate species difference in animal bone experiment, bone mineral content (BMC) was measured using dual energy X-ray absorptiometry (DXA) on the femurs of laboratory mice (Mus musculus) and rats (Rattus norvegicus), and common marmosets (Callithrix jacchus). Measures were taken on femurs in situ, detached from the body, skinned and defleshed, or dried completely. When the BMC of the bone measured in the intact limb attached to the trunk was set at 100%, the actual BMC of the dry bone was 58.7 +/- 11.5% in mice and 103.2 +/- 3.2% in rats. Similarly, the bone area (Area) and bone mineral density (BMD) of the dried femur was significantly lower in the mouse femurs than intact limb. Thus, soft limb tissue such as skin and muscle modified the BMC, Area, and BMD only in mouse but not in those from rats or marmosets. The bone mineral ratio (BMR; BMC divided by dry bone weight) was nearest to the human bone value in the rat femurs, whereas the mouse femur BMR was the most different. The BMR was proved to be a practical index in evaluating bone characteristics in laboratory animals, but the mouse femur might not be suitable as an animal model for research into the aging of human bone.

Effective assessment of use of sitters by nurses in inpatient care settings

This paper is a report of the evaluation of the impact of adopting the Patient Attendant Assessment Tool (PAAT) on nurses' requests for sitters, use of restraints, and falls and fall injury rates. Staffing should be the primary issue in eliminating risks of patient falls during hospital stays. Data were collected in two acute adult medical units of a Michigan hospital from August 2005 to February 2007. Data from three sources were merged for analyses: (1) study units' monthly reports; (2) quarterly reports of the National Database of Nursing Quality Indicators and (3) PAAT reports collected from October 2006 to February 2007. The primary outcome variables were the use of sitters, number of restraints ordered and fall and fall injury rates. Independent t-tests and correlation analyses were used for data analyses. The data before and after adopting this tool were compared using independent t-tests. The PAAT helped improve the fill/request rates for sitters. The use of soft limb holders decreased after adoption of this tool. The results also showed that if the number of sitter requests was higher, the total number of restraints would be lower but the total fall rate would be higher. Hospitals should include a tool similar to the PAAT in guidelines related to provision of constant observation or use of sitters. Further investigations of the optimum combination of staffing patterns and infrastructure are needed to promote safer hospital stays.

Music Therapy in the Psychosocial Care of Pediatric Patients with Epilepsy

ABSTRACT: Presented here is a working model of music therapy as an invaluable component to the psychosocial care of pediatric patients admitted for the diagnostic testing and treatment of epilepsy. Central to this model is the implementation of music therapy across three domains: psychoeducation to increase patient understanding and awareness, procedural support to maximize coping and compliance, and psychotherapeutic support to facilitate the expression and processing of feelings pertinent to the experience of living with epilepsy. Data collected over a four-year period in which 835 patients successfully underwent Video Electroencephalogram (diagnostic testing for epilepsy) without the use of sedation or medical controls reflect the efficacy of the model and may also suggest certain cost effectiveness as well. Doctors treat the body but music therapy treats and cures the soul's spirit, and keep it up from one day to another . . . from one week to another. I listen to the music therapist play music that quietly sooths my son's worries. I listen when music played loudly makes my son feel so strong, carefree of all worries and pain. His spirit floats to a different world of beauty. Parent of a pediatric patient Epilepsy affects an estimated 10.5 million children worldwide (Guerrini, 2006), implicating it as one of the most widely diagnosed illnesses among pediatric patients. Central to the diagnosis of epilepsy, is the Video-Electroencephalogram (VEEG), which measures the electrical activity in the brain while simultaneously recording correlative clinical (visible) data on the patient being tested. The VEEG, which involves the topical placement of twenty-six electrodes onto the patient's scalp, is not a painful procedure but it is invasive on a sensory level. This often leads to a high degree of patient resistance and non-compliance during the procedure, especially in those patients who are tactile sensitive to any degree. Many EEG laboratories regularly implement medical controls (defined as any method of physically restricting a person's freedom of movement, physical activity, or normal access to his or her body by way of papoosing or through the use of commercially manufactured devices such as vest and belt restraints, mittens, and soft limb restraints) to ease the process of electrode application. The questionable morality and humanity of restraining any child against his or her will regardless of age, is substantiated in a growing body of research (Minnick, Mion, Leipzig, Lamb, & Palmer, 1998; Mohr, Mahon, & Noone, 1998; Pridham, Adelson & Hansen, 1987), and provides impetus for this report. Additionally, the use of general anesthesia or chloral hydrate to achieve conscious sedation may be sought by the ill-prepared unit in order to ensure the successful completion of the procedure. While such interventions are made under the guise of being in the best interest of the child undergoing the procedure, this practice actually translates into a tremendously inefficient use of hospital staff and resources. The reported expense of various forms of sedation and anesthesia (Lee, Vann, & Roberts, 2001; Nelson, Hoagland, & Kunkel, 2000), as well as studies on the possible adverse effects of such intervention (Cote, Karl, Notterman, Weinberg, & McCloskey, 2000; Bluemke & Breiter, 2000; Heistein et al. 2005; Lang & Rosen 2002; Lee et al. 2002; Mascia, Koch, & Medicis, 2000; Meiser & Laubenthal, 2005; Nelson, Hoagland & Kunkel, 2000; Pershad, Palmisano, & Nichols, 1999), should generate genuine interest at the administrative level of the health industry to seek alternative means of reinforcing patient coping and compliance during minor procedures such as this one. Music therapy within the context of Child Life philosophy (American Academy of Pediatrics [AAP], 1993; Orland, 1965; Plank, 1965) is routinely implemented as both a time- and cost-effective alternative to sedation and restraining within the epilepsy-monitoring unit (EMU) of a large medical center operating in the New York metropolitan area. …