Soft Pad Research Articles

Creating a Soft Tactile Skin Employing Fluorescence Based Optical Sensing

Currently, optical tactile sensors propose solutions to measure contact forces at the tip of flexible medical instruments. However, the sensing capability of normal pressures applied to the surface along the tool body is still an open challenge. To deal with this challenge, this letter proposes a sensor design employing an angled tip optical fiber to measure the intensity modulation of a fluorescence signal proportional to the applied force. The fiber is used as both emitter of the excitation light and receiver of the fluorescence signal. This configuration allows to (i) halve the number of optical fibers and (ii) improve the signal to noise ratio thanks to the wavelength shift between excitation and fluorescence emission. The proposed design makes use of soft and flexible materials only, avoiding the size constraints given by rigid optical components and facilitating further miniaturization. The employed materials are bio-compatible and guarantee chemical inertness and non-toxicity for medical uses. In this work, the sensing principle is validated using a single optical fiber. Then, a soft stretchable skin pad, containing four tactile sensing elements, is presented to demonstrate the feasibility of this new force sensor design.

Examining the Frictional Behavior of Primitive Contact Geometries for use as Robotic Finger Pads

Prosthetic and robotic grippers rely on soft finger pads to better acquire objects of varying size, shape and surface. However, the frictional behavior of soft finger pads of different designs and geometries have yet to be quantitatively compared, in large part due to the difficulty in modeling soft contact mechanics. In this letter, we experimentally examine the frictional behavior of several common primitive contact geometries in terms of their performance under shear loads that would tend to cause the contact to slip and the grasp to potentially fail. The effective static and kinetic coefficients of friction were recorded for each finger pad under a range of common grasping loads. The results show that the variance in contact curvature, contact patch geometry and pressure distribution have influences on key parameters for grasping at low forces. The advantages and disadvantages of these simple geometries are discussed for design of single finger, multi-finger and manipulation-based robotic hands.

Prevention and Treatment of Reproductive Tract Infection

Reproductive Tract Infections (ISR) occur because of the process of entering and breeding the germs that cause infections into the female reproductive tract. Caring for sexual organs is often not done as often as caring for other organs. Though sexual organs need extra attention. In these sexual organs, the resulting sweat is quite excessive. So that the sexual organs become moist. prevention that can be done to prevent the occurrence of sexually transmitted diseases that is with care and maintain the cleanliness of the reproductive organs. Treatments that can be done are consuming healthy and nutritious eating, avoid using tight pants, check with your doctor if you experience vaginal discharge for a very long time, make it a habit to cleanse the genitals after sexual intercourse, do not use pantyliner, avoid having sexual intercourse with multiple partners. Washing the genitals every day, changing clothes frequently, at least twice a day in the bath, during menstruation, use soft pads, always wash hands before touching the genitals, avoid using other people's towels or washcloths and shave a portion of pubic hair to prevent bacterial growth

Challenges in the Automation of Eddy Current Evaluation for Aerospace‐Spacecraft Propellant Tanks

AbstractAn automated system is designed for Eddy current evaluation of spacecraft components with a proven multi‐axis industrial robot interfaced with dynamic electromechanical distance compensation device (EMDC), automated probe exchange, array eddy current probe, precision component fixtures and turntables, eddy current equipments, centralized control system to control robot and eddy current system with seamless handshake capability. Accuracy of the probe guidance system for the entire test period is ensured by the repeatable probe positioning within ±0.05mm by the robot and a minimal lift off error of ± 50μ, achieved by deploying an automated device with a high precision component turntable with positioning accuracy of £0.005°. The component is aligned initially by LASER and fine alignment is established by Infrared based touch‐tool.Automation of eddy current based evaluation technique has made the system state of the art with high probability of defect detection capability at a lesser evaluation time. Also the system has enhanced process confidence level due to the high positional accuracy of the system in comparison with manual methods, with defect detection capabilities up to depth of 0.12mm on a shell of 0.8 mm thickness. The challenges in automation of the system include intricacies due to component's thickness and also due to the complex hemispherical profile of the component. Fixtures were designed to provide enough support for the fragile components with soft pads at the contact area, and alignment of component in turntable to avoid surface run‐out errors, synchronization between turntable and the robot scanning speed, precision maintenance of lift‐off distance between eddy current probe and component surface, array eddy current probe design with multiple elements ensuring defect detection in any orientation are some of the challenges overcome in the automation of eddy current evaluation technique.The challenges in designing an automated eddy current system for evaluation of propellant tanks were systematically overcome with automation to get better defect characterization capability with reduced test time aiding in design optimization of thin walled metallic structures like propellant tanks.

PENGARUH BANTALAN KARET TERHADAP MOMEN YANG TERJADI PADA LINK SLAB BETON

The use of link slab as a substitute for expansion joints is one of the innovations that can provide benefits for bridge life, user comfort, and maintenance cost efficiency. Link slab is a slab placed on the upper surface of the adjacent girder end which forms a continuous slab system with the slab deck. In the transition zone, link slab and girder are installed in hard rubber and soft rubber pads at some thick variations in each type of rubber. Moment on the link slab is obtained due to the effect of traffic load according to SNI 1725: 2016 with the condition of the link slab without and with rubber pads. The study of the use of link slab in this paper is carried out in a numerical approach on a finite element software-Abaqus. Link slab is modeled as a 3D solid model in compressive concrete variations. In this study, the addition of hard rubber pads on link slab can reduce the magnitude of moments compared to link slab without rubber pads. This is indicated by the percentage reduction moment between 39,20-83,42% on LS-1, LS-2, and LS-3 hard rubber pads with thichness 10 mm, 20 mm and 30 mm. While on link slab with soft rubber pads is found that moments are greater at the very thick pads This is indicated by the percentage difference in moments between 198,26 – 244,58% on LS-1, LS-2, and LS-3 soft rubber pads with thickness 10 mm, 20 mm and 30 mm. This large difference is due to the effect of moment change from negative moments (initial conditions) to positive moments after the addition of soft rubber pads.

Computerized Hittite Cuneiform Sign Recognition and Knowledge-Based System Application Examples

The Hittites had lived in Anatolia more than 4000 years ago. The Hittite language is one of the oldest and may be the only one still readable and grammar rules are known member of Indo-European language family. The Hittites had a cuneiform script of their own written on soft clay pads or tablets. Tablets made durable and permanent by baking them after writing with some tools. That is why they could endure for thousands of years buried in the ground. The study of Hittite language has been made manually on the Hittite cuneiform tablets. Unfortunately, field scientists have read and translated only a relatively small number of unearthed tablets. Many more tablets are still waiting under and over ground in Anatolia for reading and translation into various languages. To read and translate the cuneiform signs, using computeraided techniques would be a significant contribution not only to Anatolian and Turkish but also to human history. In this paper, recognition of Hittite cuneiform signs by using computer based image-processing techniques is reported. Additionally, uses of data-mining applications are also included in the paper. Most importantly, the authors also demonstrated feasibility of an expert system on the Hittite cuneiform scripts.

Experimental research on the thermal conductivity of the contact pads for electronic equipment

Currently, soft contact pads of foreign manufacturers of SIL-Pad, Gap-Pad and Bond-Play series are widely used to transfer heat flows in electronic equipment elements. Within the framework of import substitution programs, the technology of manufacturing analogs of heat-conducting gaskets from local raw materials is being developed. The main thermal property that determines the performance of gaskets is the thermal conductivity. The article describes the installation, technique and methods of conducting and processing the results of experiments developed for its determination. The analysis of the obtained experimental data is made.

Soft Robotic Pad Maturing for Practical Applications.

Soft pneumatic actuators (SPAs) have existed for many years as one of the mainstream actuators. Along with the rise of soft robotics, the development in SPA designs in recent years was especially rapid and diverse. Particularly with innovations in SPA fabrication, there is an increasing variety of SPAs with different air chamber designs, varied scales, and distinctive motion modalities. Collectively, it can be seen that the majority of the SPAs come in the format of a finger-like one-dimensional actuator. To expand the SPA spectrum, this article gives a detailed and thorough introduction of a new class of SPA, called soft robotic pad (SRP). SRP is a silicone-based two-dimensional (2D) pad-like actuator that can be programmed to do a multiplicity of surface morphing without any change in thickness. We have previously reported a novel fabrication technique for SRP. However, it also came with a major issue-premature failure. Therefore, in this article, we present significant improvements in the fabrication that substantially strengthen the SRPs so that they can withstand higher pressure for future applications. In addition, shape and force modeling are also provided to predict the corresponding outputs upon different pressures. Motion tracking using Vicon system is proposed for the characterization of the 2D surface morphing. As a pioneering step, we also propose one SRP application, a soft wearable assistive pad for elbow flexion, to demonstrate its capabilities. As a new and unique member in the SPA family, SRP brings new dimension and more motion varieties to SPAs, a substantial boost to the application scope for SPAs and soft robots.

Modeling Novel Soft Mechanosensors Based on Air-Flow Measurements

In this letter, we introduce a new pneumatic mechanosensor dedicated to Soft Robotics and propose a generic method to reconstruct the magnitude of a contact-force acting on it. Changes in cavity volumes inside a soft silicon pad are measured by air-flow sensors. The resulting mechanosensor is characterized by its high sensitivity, repeatability, dynamic range and accurate localization capability in 2D. Using a regression found by machine learning techniques we can predict the contact location and force magnitude accurately when the force magnitudes are within the range of the training data. To be able to provide a more general model, a novel approach based on a Finite Element Method (FEM) is introduced. We formulate an optimization problem, which yields the contact load that best explains the observed changes in cavity volumes. This method makes no assumptions on the force range, the shape of the soft pad or the shape of its cavities. The prediction of the force also results in a model for the deformation of the soft pad. We characterize our sensor and evaluate two designs, a soft pad and a kidney-shaped sensor, in different scenarios.

Safety and Efficacy of a Trans-Eyelid Facial Rejuvenation Surgery Combining Partial Repositioning of Orbital Fat and Midface Lift in Chinese Patients: A Prospective Case Series.

To describe the combined technique of midface lift and partial release of orbital fat for facial rejuvenation and evaluate the safety and aesthetic results. This was a single-center study that included patients who underwent facial rejuvenation from January 2010 to December 2016. The orbital fat was partially removed, and the cheek fat pads were repositioned to exfoliate the myocutaneous flaps of the lower eyelids and midface through a sub-ciliary incision. The cheek soft tissue pads and orbital fat were restored and sutured to the periorbital membranes and orbital margins. Postoperatively, the patients were examined at 6 and 18 months for changes in the shapes of cheeks, eyelid joints, sunken eyepit, and nasolabial sulcus along with procedural complications. A total of 179 (177 women; 2 men) eligible patients with a mean age of 47.17 years underwent the procedure. The shapes of cheeks and eyelid joints of all patients improved, along with shallowing of the sunken eyepit and nasolabial sulcus at 6- and 18-month follow-up. The surgical procedure involved minor trauma without facial scarring, lower eyelid flinch, and dislocation. None of the patients reported complications of nerve injuries, long-term chemosis conjunctiva, periocular swelling, or dislocation of the lower eyelids. Only 2 patients who underwent subsequent pouch surgeries had slight ectropion, which was restored within 4 months of surgery. To conclude, the combined partial orbital fat repositioning and midface lift via sub-ciliary approach is a successful treatment option for facial rejuvenation with no major complications.

Performance of Trizact™ Microreplicated Pad in W Buff Marathon Process

This work demonstrates the performance of a microreplicated pad used in a W buff polish process. 3M™ Trizact™ microreplicated pads consist of matrix designed asperitity and pore structures that can be tuned independently, into a wide variety of complex 3D structures. More uniform pad asperity diameter and height control allows for better wafer-pad contact interacions. Consequently, microreplicated pads have significantly higher contact area with the wafer surface compared to industry standard hard and soft pads. The unique heringbone groove design allows for efficient slurry transportation and uniform slurry flow distribution – enabling the potential for slurry saving and cost of ownership reduction. The CMP wafer polish results show stable oxide RR (se Figure 1) and consistent W:Ox film selectivity over 3000 wafers. Wafer removal rate recovey was repeatablly fast following periods of wet idle. Stable uniformity/edge profile control were also achieved. Total defect counts were controlled and consistent throughout the duration of the 3000 wafer marathon run. Upon completion of the marathon run, the loss in pad asperity height loss was less than 3 microns (14 %) compared to initial asperity height illustrating the potential to extend the pad life significantly beyond 3000 wafers (see Figure 2). The results illustrate the benefit of micro-replicated asperities in CMP pads, These results are important because of the potential to improve pad performance and reduce the cost of CMP. Figure 1

On the Planarization Mechanism and Pad Aging Effects of Soft Pad Polishing: A Perspective From the Micro-Mechanical Properties of Soft Pads

The local viscoelastic properties of soft polishing pads with different usage durations are measured by a micro-scale mechanical analysis testing platform. The testing reveals stimulus-adaptive local viscoelasticity of soft pads under the activation of asperity contact. This phenomenon suggests asperity-dependent local modulus. Such an increase of local modulus induced by higher asperity provides a further enhancement effect to the planarization of surface asperity. Furthermore, the measurement outcomes suggest that the reaction of local micro-scale viscoelastic properties of the soft pad surface to the workpiece asperity will decay with usage time. The current study provides a detailed understanding of the aging effects for the soft pad and explains the performance decay during soft pad polishing from a local micro-scale interfacial perspective.

"Keep your feet on the ground": Simulated range of motion and hind foot posture of the Middle Jurassic sauropod Rhoetosaurus brownei and its implications for sauropod biology.

The biomechanics of the sauropod dinosaur pes is poorly understood, particularly among the earliest members of the group. To date, reasonably complete and articulated pedes in Early Middle Jurassic sauropods are rare, limited to a handful of taxa. Of these, Rhoetosaurus brownei, from eastern Australia, is currently the only one from the Gondwanan Middle Jurassic that preserves an articulated pes. Using Rhoetosaurus brownei as a case exemplar, we assessed its paleobiomechanical capabilities and pedal posture. Physical and virtual manipulations of the pedal elements were undertaken to evaluate the range of motion between the pedal joints, under both bone-to-bone and cartilaginous scenarios. Using the results as constraints, virtual reconstructions of all possible pedal postures were generated. We show that Rhoetosaurus brownei was capable of significant digital mobility at the osteological metatarsophalangeal and distal interphalangeal joints. We assume these movements would have been restricted by soft tissue in life but that their presence would have helped in the support of the animal. Further insights based on anatomy and theoretical mechanical constraints restricted the skeletal postures to a range encompassing digitigrade to subunguligrade stances. The approach was extended to additional sauropodomorph pedes, and some validation was provided via the bone data of an African elephant pes. Based on the resulting pedal configurations, the in-life plantar surface of the sauropod pes is inferred to extend caudally from the digits, with a soft tissue pad supporting the elevated metatarsus. The plantar pad is inferred to play a role in the reduction of biomechanical stresses, and to aid in support and locomotion. A pedal pad may have been a key biomechanical innovation in early sauropods, ultimately resulting in a functionally plantigrade pes, which may have arisen during the Early to Middle Jurassic. Further mechanical studies are ultimately required to permit validation of this long-standing hypothesis.

The noise radiated by ballasted and slab tracks

Conventional railway track is supported by a layer of crushed stones known as ballast. In recent years concrete slab tracks have been introduced which have been used widely in the construction of high-speed lines. However, a particular concern is that slab track is considered to be noisier than ballasted track. In order to investigate the differences in the noise radiation characteristics of ballasted and slab tracks, the TWINS model for rolling noise has been updated. Differences are included in the sound radiation of the rails and sleepers due to the presence of absorptive or reflective ground and the effect of the ballast vibration on the sound radiation of the sleepers is taken into account. The effects of the ballast absorption under the train on the sound propagation are also considered. To calculate the sound radiation from the slab itself, a waveguide finite element/boundary element method is used, which includes the supporting ground. The slab vibration is shown to be the dominant noise source only up to around 100 Hz, whereas it is negligible at higher frequencies. Results are presented for two ballasted tracks (one with stiff rail pads and the other with soft pads) and one slab track, and compared with measured data. Finally, the sound radiation from the various tracks are compared for equivalent situations. The results are found to depend on the assumptions made, particularly in relation to the track decay rates and roughness spectra; the ground conditions adjacent to the track also affect the sound pressure spectra below 1 kHz.

Impact Attenuation of the Soft Pads and the Wearable Airbag for the Hip Protection in the Elderly

Hip fractures caused by the falls in the elderly can lead to serious injuries that diminish their quality of life. The soft pads and wearable airbag have been developed and commercialized to prevent hip fractures of the elderly. In this study, the hip impact simulator was developed and the impact forces of six types soft pads and the hip protection airbag were measured by using the hip impact simulator. In addition, the distribution of the impact force and maximum contact area were also measured by attaching the pressure sensor on the surrogate pelvis of the hip impact simulator. Experiments were performed depending on the conditions protecting the surrogate pelvis (unpadded, soft pad, airbag) and the fall from 20 to 40 cm heights were repeated three times depending on each condition. The hip protection airbag decreased the mean pressure applied on the hip joint by decreasing a peak impact force according to the increased maximum contact area compared to the unpadded and soft pad conditions at all fall heights. Therefore, it can be concluded that the hip protection airbag can prevent the hip fracture by effectively attenuating impact force during falls in the elderly.

Gripping ease in southern green stink bugsNezara viridulaL. (Heteroptera: Pentatomidae): Coping with geometry, orientation and surface wettability of substrate

AbstractThe southern green stink bugNezara viridulaL. (Heteroptera, Pentatomidae) is highly polyphagous, preferring apically situated seeds and fruits on more than 150 plant species belonging to over 30 plant families all over the world. This forces them to move over highly variable terrains, including plant stems, leaves, pods and buds, which requires efficient attachment. Stink bugs have long slender legs and feet (tarsi) equipped with paired curved claws, paired soft adhesive pads (pulvilli), and flattened lanceolate hairs (setae), which arise ventrally on the first and second foot segments (tarsomeres). To characterize their attachment abilities on well‐defined test substrates, here we comparatively measured and analyzed the traction forces of bugs walking horizontally and vertically on hydrophilic (water attractive) and hydrophobic (water repellent) glass plates and rods. The latter correspond to the geometry of preferred feeding sites of stink bugs in the field. The results show a clear contribution of tarsal flattened lanceolate hairs to the stink bug's attachment. Higher traction forces are generated on a glass rod than on a glass plate, corresponding to up to individual maximum of 43 times the stink bug's body weight. Substrate hydrophobicity promotes the attachment, while the measured forces are up to eight times lower when tarsal hairs are disabled. The combination of smooth and hairy tarsal pads results in a remarkable attachment ability, which enablesN. viridulato climb unstable apical plant parts, and supports their invasive behavior and global dispersion.

Smart Fetal Care

The exam of fetal well-being during routine prenatal care plays a crucial role in preventing pregnancy complications and reducing the risks of miscarriages, birth defects and other health problems. However, the conventional prenatal screening and diagnosis is conducted by medical professionals in a clinical environment, which is subject to certain limitations such as manpower, medical devices and location, time and cost of services, etc. This paper presents a new approach to detect and monitor fetal movement safely and reliably without any constrains of time, environment and cost. Unlike the conventional method, our contribution includes a novel soft sensor pad which can automatically detect fetal movement and uterine contraction nonintrusively and the robust data analysis software to monitor pregnancy health and screen abnormalities with quantitative assessment. The monitoring belt embedded with the soft sensor pad is wearable, non-intrusive, radiation free and washable. The new algorithms are robust for noise removal, feature extraction, time sequence data analysis and decision support to achieve personalized care. Both the design of soft sensor pad and functions of the belt are original and unique. The results of preliminary clinical trials demonstrate the feasibility and advantages of our prototype.

Electroadhesion for soft adhesive pads and robotics: theory and numerical results.

Soft adhesive pads are needed for many robotics applications, and one approach is based on electroadhesion. Here we present a general analytic model and numerical results for electroadhesion for soft solids with an arbitrary time-dependent applied voltage, and an arbitrary dielectric response of the solids, and including surface roughness. We consider the simplest coplanar-plate-capacitor model with a periodic array of conducting strips located close to the surface of the adhesive pad, and discuss the optimum geometrical arrangement to obtain the maximal electroadhesion force. For surfaces with roughness the (non-contact) gap between the solids will strongly influence the electroadhesion, and we show how the electroadhesion force can be calculated using a contact mechanics theory for elastic solids. The theory and models we present can be used to optimize the design of adhesive pads for robotics application.

Improvements and Evaluation of an In-Field Bin Filler for Apple Bruising and Distribution

Abstract. Automatic bin filling is needed for apple harvest and in-field sorting. A commercially viable bin filler for in-field use should be simple, compact, low in cost, and be able to distribute apples evenly in the bin without causing bruising damage. An innovative bin filling technology was developed for incorporation with the new apple harvest and in-field sorting machine recently developed by our group. Field tests of the first version of the bin filler in the 2016 harvest season showed relatively high bruising rates and uneven fruit distributions. Subsequently, a second version of the bin filler was developed with several major improvements. A new pair of foam rollers for better control of apples exiting the sorting system and avoiding fruit collisions during free falling was added below the sorter. An improved pinwheel with nine longer soft pads, instead of four short pads as in the original version, was installed for better fruit distribution. Foam guides, attached to the long pads, reduced the rolling speed of fruit from the pads into the bin. Field tests conducted in the 2017 harvest season showed that the second, improved version of the bin filler achieved superior performance in reducing bruise damage, with 99% of ‘Gala’ apples and 98% ‘Blondee’ of apples graded Extra Fancy. Furthermore, a depth imaging method, using a Kinect-v2 camera, was proposed to quantitatively compare the performance of the two bin fillers for distribution of fruit in the bin under uniform and non-uniform feeding conditions. Analysis of the fruit height data showed that the apple distributions were not significantly affected by feeding method for both bin fillers. Overall, the second version of the bin filler resulted in better distributions of apples in the bin, compared to the first version, and uneven distributions mainly occurred in the corners of the bin, which could not be reached by the bin filler’s pinwheel. The improved bin filler meets the requirements for apple harvest and in-field sorting, and it has potential for use with other harvest platforms. Keywords: 3D imaging, Apple, Bin filling, Bruising, Harvest, Sorting.

Mechanics of wet adhesion in soft interaction with patterned morphology

Locking surfaces with a wet interface can enhance interactions between a grasped object and a soft pad. This paper presents a mechanical approach to understanding the role of morphological design in achieving wet adhesion for secure grasping by a soft pad. Two conditions were compared in modeling wet interfaces between an object and a soft pad: a pad with a flat surface, and a pad with a micropatterned surface. The latter was designed and analyzed based on the wet attachment between the surface of a tree-frog’s toes and its substrate. In this model, we proposed a method to estimate the contact force in both normal and tangential directions between a soft pad with a micropattern surface and a rigid flat surface substrate. A square mold containing 3600 85 μm × 85 μm cells interspaced by grooves 15 μm wide and 15 μm deep was fabricated, using e-beam technology, as the micropattern pad. The generated normal and tangential contact forces of the pad with a micropattern surface, and a pad with a flat surface were measured in both normal and tangential directions under wet conditions. Experimental results showed good agreement with theoretical results, indicating that the micropattern significantly enhanced the contact force of the pad by approximately two-fold for the normal and 1.2- to 1.4-fold for the tangential force. This theoretical approach can be potentially utilized to investigate the association of soft pad morphology with wet adhesion, and enhance efficient grasping by soft robotic hands in wet and high-moisture environments.