Inflatable Arm Research Articles

A Novel Inflatable Actuator Based on Simultaneous Eversion Retraction.

Inflatable robotics is a promising area for the deployment of low-cost structures that are easy to transport and deploy while allowing safe interactions with humans and the environment. One of the key elements in the development of inflatable robots is their actuation system. In this work, we introduce the original concept of a Simultaneous Eversion-Retraction Inflatable Actuator, used in the actuation of an inflatable joint of a long-range manipulator. Through an analytical study, simple relations about the total stroke and the effective area are obtained. These relations are compared to finite elements simulations and contrasted with experimental data obtained from tensile tests of an actuator prototype. The results show that the proposed design outperforms existing concepts in terms of total stroke and force distribution through the entire stroke, which makes it suitable for the actuation of long reach inflatable arms.

Design, fabrication, modeling and control of a fabric-based spherical robotic arm

In this paper we present a spherical soft robotic arm made from fabric. The inflatable arm has a small mass and is pneumatically actuated. A configuration is employed with only three actuators controlling the two rotational degrees of freedom of a spherical joint. This differs from the commonly employed antagonistic pairs, including four actuators for two degrees of freedom. The fabrication procedure of the lightweight and compliant system is discussed in detail and uses commonly available materials and tools. The capability of the robotic arm to adjust the joint stiffness as a function of the actuator pressures is investigated and characterized for different deflection directions. The static mapping from the actuator pressures to the orientation of the robotic arm is identified from data and the inverse mapping is employed in a position controller. The modeling and controller derivation are performed for three different stiffness levels demonstrating the ability of the spherical robotic arm to change the joint stiffness independently of controlling the position. The position tracking performance is experimentally evaluated by tracking a square trajectory. A comparison of the tracking performance for the different stiffness levels shows that accurate tracking is more challenging for the smallest joint stiffness. A gray-box model capturing the interactions of the two degrees of freedom is used in a learning scheme that is applied for the smallest stiffness level. The learning approach reduces interactions between the two degrees of freedom and demonstrates the control performance achievable with the system developed.

Design and structural analysis of an inflatable coated fabric manipulation arm

This paper presents the structural behaviour of a novel inflatable manipulation arm, which consists of inflatable coated fabric tubes and bellows-type joints. In order to minimise the actuation moment, a rotational joint with creases, analogous to a spacesuit elbow, has been introduced. The biaxial tensile and shear tests have been carried out to evaluate the elastic constants of the PVC-coated polyester fabric membranes of the inflatable arm. Finite element analysis has been carried out to predict the mechanical behaviour of the inflated arm structure. Effects of the internal pressure on the arm deflection, and influence of crease geometric parameters, e.g. number, width and depth on the rotation performance are evaluated. A prototype of the inflatable arm has been developed to perform an experimental investigation on its rotational behaviour. Good correlations have been found between the predictions and the experimental results. The current work on a representative single-joint inflatable arm unit provides the rationale and knowledge to develop long range multi-joint manipulators.

Preeclampsia and the 20th century: "Le siècle des Lumières".

The authors delineate seven quantum leap forward and, or revolutions having occurred during the 20th century in the understanding of the physiopathology of preeclampsia. First the discovery of the inflatable arm band permitting to measure blood pressure in 1896. Second, the discovery that eclamptic (convulsions), and later "pre"eclamptic (proteinuria) women presented hypertension in 1897 and confirmed in 1903, discovery of the hypertensive disorders of pregnancy. Third, the eight major textbooks published all along the 20th century by delineating risk factors of preeclampsia with the concept of "preeclampsia, disease of primigravidae". Fourth, the discovery in the 1970's that human trophoblast implantation was far deeper than in other mammalian species. Fifth, and a major step forward, description at the end of the 1980's that the maternal syndrome in preeclampsia (glomeruloendotheliosis, HELLP syndrome, eclampsia) could be unified in a global endothelial cell inflammation. Sixth, the epidemiological descriptions in the 1970-1990's that indeed preeclampsia was a disease of first pregnancies at the level of a couple ("primipaternity concept"), leading to an explosion in immunological research in the last decade, beginning in 1998. Seventh and finally, in the search for the "factor X" explaining the vascular inflammation in preeclamptic women (inositol phospho glycans P-type were described in 2000, while soluble Flt-1 and S-endoglins have been clearly predicted since 1997). The majority of the seeds or findings have been grounded or realized in the 20th century. Indeed, for preeclampsia, the 20th century has been le "Siècle des Lumières" (the Enlightments).

Design, Kinematics, and Control of a Multijoint Soft Inflatable Arm for Human-Safe Interaction

In this paper, a novel soft inflatable arm is proposed for telepresence robots. The new proposed structure of the arm is achieved by a very common and low-cost inflatable material and it is very light, weighing only about 50 g. However, it can realize agile movement by driving six tiny cables installed in the shoulder and elbow joints. The soft inflatable arm can work by pumping air at a very low pressure ( $7.32 \pm 3.45$ kPa) and allows direct and soft human contact without any external force sensors. This paper proposes joint compressed models, joint kinematic models, and kinematic models for the whole inflatable robot arm. These models can be easily applied to multijoint arms. In addition, a new redundancy resolution method is also developed for the inflatable arm, which makes it easier to control resolution and is less complex than other traditional approaches. Numerous experiments have been conducted, including performances of accuracy, repeatability, motion trajectories, human-safe interaction, and remote interaction. Results are satisfactory and validate the expected performance of the proposed robotic arm.

Maternal and placental preeclampsia. Physiopathological and geographical differences

Eclampsia (together with epilepsy) being the first disease ever written down since the beginning of writings in mankind 5000 years ago, we will make a brief presentation of the different major steps in comprehension of pre-eclampsia. (1) 1843 Lever, description of proteinuria, (2) 1903 Cooks & Briggs discovery of gestational hypertension (7 years after the invention of the inflatable arm band in 1896 by a young 31 year-old Italian physician Riva-Rocci), (3) End of the 1970’s, description of the “double” trophoblastic invasion existing only in humans, (4) between the 1970s and the 1990s, description of preeclampsia being a couple disease. The “paternity problem” (and therefore irruption of immunology), (5) at the end of the 1980s, a major step forward: Preeclampsia being a global endothelial cell disease (glomeruloendotheliosis, hepatic or cerebral vascularitis, HELLP, eclampsia), inflammation, (6) end of the 1990s: Consensus for a distinction between early onset preeclampsia EOP and late onset LOP (34 weeks gestation), EOP being rather a problem of implantation of the trophoblast (and the placenta), LOP being rather a pre-existing maternal problem (obesity, diabetes, coagulopathies etc…). LOP is predominant everywhere on this planet, but enormously predominant in developed countries (those who publish and have the means to do research): 90% of cases. This feature is very different in countries where women have their first child very young (88% of world births), where the fatal EOP (early onset) occurs in more than 30% of cases. (7) and finally, we will approach the current stage in 2016: What is the common factor which could explain the maternal global endotheliosis in EOP and LOP?

Sleepers Versus Nonsleepers

There is growing evidence that an elevated nocturnal blood pressure is associated with an adverse cardiovascular outcome. In the Dublin Outcome Study, for each 10-mm Hg increase in mean nighttime systolic blood pressure, the mortality risk increased by 21%.1 At present, ambulatory blood pressure measurement is the only technique that permits close examination of the circadian profile and identification of patterns that may be associated with risk. Much happens to the cardiovascular system at nighttime, especially in relation to blood pressure. The patterns of nocturnal blood pressure–nocturnal hypertension, nocturnal hypotension, dipping and nondipping, reverse dipping, and autonomic failure–have been largely ignored in clinical practice. Many studies evaluating morbidity and dipping status have supported the concept that a diminished nocturnal blood pressure fall is associated with a worse prognosis.2 However, despite compelling evidence that changes in nighttime blood pressure may hold many secrets that, if unlocked, might benefit the clinical management of hypertension, there has been reluctance to focus on nocturnal blood pressure both clinically and in hypertension research.3 The nocturnal period of the 24-hour blood pressure profile, which is surprisingly complex, can be divided into a number of windows in which discrete phenomena may occur. These windows are the retiring (or perhaps more aptly named vesperal) window, the nighttime (or basal) window during which sleep is most likely, and the preawakening (or matinal) window, which precedes rising. In the normal individual there is a decline in blood pressure in the vesperal window from daytime levels of blood pressure to reach a plateau during the basal window (the “dipping” pattern), with a modest rise in the matinal window to regain daytime levels of blood pressure.4 In hypertensive patients (or …

Is hand splinting effective for adults following stroke? A systematic review and methodologic critique of published research.

Upper limb hemiplegia after stroke is common and disabling. Hand splints are widely used to prevent contracture and reduce spasticity. To assess the effectiveness of hand splinting on the hemiplegic upper extremity following stroke. A search was conducted of the Cochrane Central Register of Controlled Trials; the electronic databases MEDLINE, EMBASE, CINAHL, PEDro, SCI, SSCI; websites of professional associations; reference lists in trial reports and other relevant articles. Studies of the effect of upper extremity splinting on motor control, functional abilities, contracture, spasticity, or pain in the hand or wrist. Validity of studies was assessed systematically and a content analysis was conducted of the methodologies used. Methodological quality of randomized trials was rated by two independent assessors using the PEDro scale. Nineteen studies were appraised for content. Of these, most (63%) were reports of case series. Four studies (21%) were randomized controlled trials. Methodological scores of trials ranged from 2 to 8 (maximum possible score 10). One trial of nominally 'medium' quality reported that inflatable arm splinting makes no difference to hand function (mean difference on Fugl-Meyer Assessment -0.12, 95% confidence interval (CI) -9.8 to 9.6). The remaining trials investigated effects of thermoplastic splints; one trial of 'high quality' reported no difference in contracture formation in the wrist and finger flexor muscles after wearing a hand splint which positioned the wrist in the traditional functional position for 12 hours each night for four weeks (mean difference in range of movement after four weeks was 1 degree, 95% CI -3.7 degrees to 6.1 degrees; power >80%). All remaining trials were of poor methodological quality. Limited research and lack of a no-splint control group in all trials to date limit the usefulness of these results. REVIEWER'S CONCLUSION: There is insufficient evidence to either support or refute the effectiveness of hand splinting for adults following stroke.