Soft Objects Research Articles

Stitching soft matter

In this practice, I have been examining an ecology of touch through the filter of post-humanism and Karen Barad’s motive concepts of intra-action, re-turn and diffraction. The practice, inevitably affected by COVID-19, has led to a virtual iteration of the process and the continued development of soft matter during the pandemic has allowed me to reflect on the ghostly traces of touch left in materials and sensed in the body. The resulting soft matter objects will be employed as choreographic scores to wear, think through and move within an inherited field of touch, affect and echoes of ghostly matter.

Liquid Metal Transformable Machines

ConspectusConventional robots can accomplish defined tasks but often encounter troubles when handling irregular objects under unstructured environments. Soft robots, with supercompliance, large transformation, and high environmental adaptability, hold big promise for delicate manipulations such as grasping soft objects or delivering precious biomedical samples. Even a step further, if soft robots are endowed with the extraordinary behaviors to freely transform among different morphologies and constructions just like those already existing in literature and science fiction films, more fantastic challenges can be tackled. Representing one of the most potential robotic soft materials, liquid metals have been given sufficient expectations on realizing the transformable machines that might fundamentally reform modern daily life. Accordingly, inspiring discoveries on controllable transformations of the liquid metal have been obtained surprisingly and tremendous efforts have been made over the past decade, indicating a significant step toward such a formidable dream. It is clear that the discovery of liquid metal-based large-scaled transformation with several hundred-fold fast change on the surface area opens a brand new direction of manufacturing future transformable machines. Even unusual findings on a self-fueled liquid metal with biological life-like behavior to freely explore the unknown space that solves the energy supply issue also came into being, holding big promise for making bionic transformable robots. This Account aims to systematically sort out the developmental history of liquid metal transformable machines with special focus on the fundamental scientific discoveries, the underlying mechanisms, and the potential applied scenarios based on liquid metal enabled solid–liquid hybrids. The fantastic properties and unique transformation capabilities of liquid metals have built the basis for a new era of designing soft robotics and we believe that liquid metal transformable machines are evolving into new forms of soft robots.

Increasing self-other similarity modulates ethnic bias in sensorimotor resonance to others' pain.

The tendency to simulate the pain of others within our own sensorimotor systems is a vital component of empathy. However, this sensorimotor resonance is modulated by a multitude of social factors including similarity in bodily appearance, e.g. skin colour. The current study investigated whether increasing self–other similarity via virtual transfer to another colour body reduced ingroup bias in sensorimotor resonance. A sample of 58 white participants was momentarily transferred to either a black or a white body using virtual reality technology. We then employed electroencephalography to examine event-related desynchronization (ERD) in the sensorimotor beta (13–23 Hz) oscillations while they viewed black, white and violet photorealistic virtual agents being touched with a noxious or soft object. While the noxious treatment of a violet agent did not increase beta ERD, amplified beta ERD in response to black agent’s noxious vs soft treatment was found in perceivers transferred to a black body. Transfer to the white body dismissed the effect. Further exploratory analysis implied that the pain-related beta ERD occurred only when the agent and the participant were of the same colour. The results suggest that even short-lasting changes in bodily resemblance can modulate sensorimotor resonance to others’ perceived pain.

Reconstruction of Colored Soft Deformable Objects Based on Self-Generated Template

In reconstructing soft objects under different deformation states with RGB-D sensors, the results usually suffer from incomplete geometries and textures due to self-occlusion, such as dynamic wrinkles on a garment. A priori template is usually used for addressing this issue, but it requires complex scanning and an elaborate setup. This paper proposes a new framework to reconstruct a deformable soft object with complete geometry and consistent texture by introducing an incremental-completion self-generated template (SGT). By building a non-rigid registration that combines geometry and optical flow features, the SGT is dynamically updated and completed by supplementing the information from each initial state model. Then the updated SGT is reversely deformed to each state to obtain a sequence of dynamic reconstructed results with consistent geometry. Furthermore, a consistent Markov random field is also proposed to constrain mesh models in different states to generate consistent texture and guide non-rigid deformation. Experimental results show that our method achieves multi-state high-quality reconstruction effects, which provides a new solution for dynamically reconstructing colored soft objects.

Softness-Adaptive Pinch-Grasp Strategy Using Fingertip Tactile Information of Robot Hand

We develop a tactile information-based pinch-grasp strategy enabling a robot hand to adaptively grasp easily deformable soft objects. When a robot hand has to perform grasping tasks, the grasp planner develops the grasping strategy based on visual information. However, the intrinsic properties of the target object, such as softness, cannot be detected appropriately using only visual feedback. To overcome this fundamental limitation, we aim to develop a softness-adaptive pinch-grasp strategy using fingertip tactile information. To achieve this, we first categorize soft objects based on the characteristic of resistance to deformation. Moreover, we design a three-dimensional tactile sensor that provides tactile information by measuring and localizing the distributed forces induced on its fingertip. In devising the adaptive grasp strategy, we focus on developing an algorithm that enables a robot hand to grasp soft objects by minimizing object deformation by controlling the pinch force based on the tactile feedback. The experimental results demonstrate that object deformation can be reduced by up to approximately 83.5% by the proposed strategy.

Acoustic radiation force and torque on objects with continuous and discrete inhomogeneity

At the Fall ASA meeting in 2019, the Born approximation was extended to acoustic radiation force and torque on objects of arbitrary shape with spatially varying density and compressibility [Proc. Meet. Acoust. 39, 045007 (2020)]. This model is applied here to a standing plane wave incident on objects either with continuously varying material properties or composed of connected homogeneous regions with different material properties. The approximation for inhomogeneous objects is subject to the same restrictions on incident field structure, scatterer size, and material contrast as for homogeneous objects. Results are presented for cylinders with a variety of strongly asymmetric inhomogeneity distributions. Closed-form expressions are obtained for a sphere with material properties that vary linearly with distance from its center and for a sphere surrounded by concentric spherical layers. Results for the latter case are shown to be in close agreement with existing theory for the radiation force on a nucleated cell modeled as a multilayered compressible sphere [Wang et al., J. Appl. Phys. 122, 094902 (2017)]. The Born approximation thus proves convenient for determining radiation force and torque on soft objects with both arbitrary shape and inhomogeneity. [TSJ was supported by the ARL:UT McKinney Fellowship in Acoustics.]

Hollow MXene Sphere-Based Flexible E-Skin for Multiplex Tactile Detection.

Skin-like electronics that can provide comprehensively tactile sensing is required for applications such as soft robotics, health monitoring, medical treatment, and human-machine interfaces. In particular, the capacity to monitor the contact parameters such as the magnitude, direction, and contact location of external forces is crucial for skin-like tactile sensing devices. Herein, a flexible electronic skin which can measure and discriminate the contact parameters in real time is designed. It is fabricated by integrating the three-dimensional (3D) hollow MXene spheres/Ag NW hybrid nanocomposite-based embedded stretchable electrodes and T-ZnOw/PDMS film-based capacitive pressure sensors. To the best of our knowledge, it is the first stretchable electrode to utilize the 3D hollow MXene spheres with the essential characteristic, which can effectively avoid the drawbacks of stress concentration and shedding of the conductive layer. The strain-resistance module and the pressure-capacitance module show the excellent sensing performance in stability and response time, respectively. Moreover, a 6 × 6 sensor array is used as a demonstration to prove that it can realize the multiplex detection of random external force stimuli without mutual interference, illustrating its potential applications in biomimetic soft wearable devices, object recognition, and robotic manipulation.

Infant Injury Prevention Education for Pregnant Women Attending Antenatal Class: A Quasi-Experimental Study.

It is important to educate caregivers in order to prevent infant injuries. However, there have been few studies on the effects of education on pregnant women. This study aimed to evaluate the effects of injury prevention group education on this group. Study participants were recruited from a group of pregnant mothers attending an antenatal class in Tokyo. Participants were assigned to either the intervention or control group based on the month in which they attended the existing antenatal class. Both groups received a leaflet on injury prevention, but only the intervention group received an additional short one-shot lecture. The implementation of each of the nine safety practices was assessed during home visits after childbirth. Of the 131 study participants (56 in the control group and 75 in the intervention group), 106 (80.9%) received home visits after birth. Mothers in the intervention group implemented three practices significantly more than those in the control group: Keep soft objects away from the baby’s head (38.3% vs. 13.0%), Do not place your baby on a high surface (74.6% vs. 52.2%), and Use the baby carrier correctly (93.3% vs. 76.1%). In the future, we plan to follow up the participants to evaluate the program’s long-term effects, and to continue to improve the program.

Neonatal Intensive Care Nursing Pressure Injury Prevention Practices: A Descriptive Survey.

The purpose of this study was to explore neonatal nursing practices for neonatal pressure injury (PI) risk assessment, pressure redistribution surface use, and moisture management. A descriptive survey. A sample of 252 neonatal nurses mainly from the United States responded to a survey distributed electronically through the National Association of Neonatal Nurses, the Academy of Neonatal Nurses, and on the Wound Source Web site. Nurses responded to questions that explored what neonatal nurses used to assess PI risk, types of pressure redistribution surfaces used for neonates, and what moisture management strategies were used to prevent PIs. Descriptive statistics were used to describe nurses' practices. When assessing risk, 78% (n = 197/252) reported using a risk assessment scale: the 2 most common scales were the Neonatal Skin Risk Assessment Scale and the Braden Q Scale. Sixty-nine percent (n = 174/252) reported using a rolled blanket or small soft object as pressure redistribution surfaces. In addition, 15% (n = 39) reported the use of different types of positioners such as a fluidized positioner as pressure redistribution surfaces; however, these are marketed as a positioning devices. It appears that these interventions were considered redistribution surfaces by the nurses. For moisture management, petrolatum-based products (6.7%; n = 17/252) and ostomy powders (6%; n = 16/252) were most frequently used. Practices for PI prevention are different for neonatal patients due to their gestational age, size, and level of illness. Findings from this study create a beginning knowledge of and an opportunity for further research to determine how these practices affect outcomes such as PI incidence and prevalence.

Classification of Rigid and Non-Rigid Objects Using CNN

Classifying moving objects in video surveillance can be difficult, and it is challenging to classify hard and soft objects with high Accuracy. Here rigid and non-rigid objects are limited to vehicles and people. CNN is used for the binary classification of rigid and non-rigid objects. A deep-learning system using convolutional neural networks was trained using python and categorized according to their appearance. The classification is supplemented by the use of a data set, which contains two classes of images that are both rigid and not rigid that differ by illuminations.

Soft haptic sensation increases the expectation in the social context but not in the non-social context.

Previous studies have proposed that holding soft objects can increase expectations to be included in a Cyberball task. The present study investigated whether effects of holding soft objects on expectations are restricted to social contexts or can appear in non-social contexts. Sixty-six participants performed a social or non-social ball task, both modified versions of the Cyberball task. In the social ball task, participants were told that they would play a ball-tossing game with computer-generated players. In the non-social ball task, participants were told that they would take part in a judgement task. During the task, participants held either soft or hard cushions, and their electroencephalographic signals were recorded to evaluate the contingent negative variation (CNV), which is considered to reflect expectation and anticipation of an imperative stimulus. The results showed that participants who performed the social ball task exhibited larger late CNV when they held the soft cushion compared to when they held the hard cushion, whereas participants who performed the non-social ball task exhibited no such difference. The results indicate that holding soft objects increases expectations to be included only in social contexts.

LaSeSOM: A Latent and Semantic Representation Framework for Soft Object Manipulation

Soft object manipulation has recently gained popularity within the robotics community due to its potential applications in many economically important areas. Although great progress has been recently achieved in these types of tasks, most state-of-the-art methods are case-specific; They can only be used to perform a single deformation task (e.g. bending), as their shape representation algorithms typically rely on "hard-coded" features. In this paper, we present LaSeSOM, a new feedback latent representation framework for semantic soft object manipulation. Our new method introduces internal latent representation layers between low-level geometric feature extraction and high-level semantic shape analysis; This allows the identification of each compressed semantic function and the formation of a valid shape classifier from different feature extraction levels. The proposed latent framework makes soft object representation more generic (independent from the object's geometry and its mechanical properties) and scalable (it can work with 1D/2D/3D tasks). Its high-level semantic layer enables to perform (quasi) shape planning tasks with soft objects, a valuable and underexplored capability in many soft manipulation tasks. To validate this new methodology, we report a detailed experimental study with robotic manipulators.

Chemical-mediated translocation in protocell-based microactuators

Artificial cell-like communities participate in diverse modes of chemical interaction but exhibit minimal interfacing with their local environment. Here we develop an interactive microsystem based on the immobilization of a population of enzyme-active semipermeable proteinosomes within a helical hydrogel filament to implement signal-induced movement. We attach large single-polynucleotide/peptide microcapsules at one or both ends of the helical protocell filament to produce free-standing soft microactuators that sense and process chemical signals to perform mechanical work. Different modes of translocation are achieved by synergistic or antagonistic enzyme reactions located within the helical connector or inside the attached microcapsule loads. Mounting the microactuators on a ratchet-like surface produces a directional push-pull movement. Our methodology opens up a route to protocell-based chemical systems capable of utilizing mechanical work and provides a step towards the engineering of soft microscale objects with increased levels of operational autonomy.

Position/force modeling and analysis of a piezo-driven compliant micro-gripper considering the dynamic impacts of gripping objects

The compliant micro-gripper driven by piezo actuator has emerged as a representative end-effector in micro-manipulations. To achieve high performance gripping of tiny and fragile objects, the switched position/force modeling approach has been well explored for such systems. In the present work, we investigate a lever-bridge-lever type piezo-driven compliant micro-gripper and develop a new position/force model to describe both kineto-statics and dynamics of the micro-gripper, where the free motion and gripping motion states in the manipulation process are unified in the modeling approach. In particular, the impacts of gripping objects on the dynamic properties of the gripper (in gripping motion state) are incorporated by considering the gripping object as a spring-damper system with a characteristic length. With this, the dynamic model can better predict the position of the gripping jaw and the contact position of the object, as well as the force applied on the object, which also offers the capability to estimate the stiffness of unknown objects in manipulations. Various gripping experiments with soft and stiff objects of different dimensions are conducted, which demonstrate the effectiveness and accuracy of the proposed modeling approach.

Dual‐Responsive Soft Actuator Based on Aligned Carbon Nanotube Composite/Graphene Bimorph for Bioinspired Applications

AbstractNanocarbon‐based polymer actuators have attracted significant attention because of their excellent actuation performance. In this study, a soft bimorph actuator composed of an anisotropic carbon nanotube (CNT)–polymer composite and reduced graphene oxide (rGO) film is fabricated by a simple blade‐coating method. Owing to the excellent electrical, optical, and thermal properties of the CNT and rGO, the actuator exhibits dual‐responsive actuation. It generates reversible bending deformation with a displacement of ≈13 mm under low electrical voltage stimulation or white light irradiation. Furthermore, because of the embedment of aligned CNTs in polymer matrix, this actuator exhibits excellent mechanical output compared with many of the reported nanocarbon‐based actuators. It can lift a 2.048 g clip to a height of ≈5 mm under low electrical voltage stimulation. Based on this soft actuator with dual response and good mechanical output, various bionic devices are designed. A bionic eagle claw that grasps a soft object under electrical stimulation and an artificial flower blooming in response to light irradiation are constructed. Moreover, a light‐driven smart curtain and a seagull robot are fabricated. These results reveal the great potential of the dual‐responsive anisotropic soft actuator in soft robots and smart devices driven by electricity and light.

Chewing behaviour in dogs – A survey-based exploratory study

Chewing is a behavioural element of feeding, but dogs also chew on or dissect non-edible items. This can cause considerable problems to owners if directed at household objects. Nevertheless, the provision of chewing material, associated risks and relationships with chewing behaviour and other owner-dog activities have not been investigated so far. The aim of this online survey was to explore how dog owners manage the chewing behaviour of their dog and whether there are relationships to other owner-dog interactions. Of our self-selected participants (1439 filled in the entire questionnaire), 94 % provided their dogs with edible chewing material (e.g., rawhide, dried innards, meat), 83 % provided inedible chew toys, 73 % provided chew toys filled with food and 51 % provided hard chewing material (e.g. wood, antlers). Edible materials were provided four to six times a week by the average dog owner. Regarding risks, 67 % of respondents stated that their dog never had a problem caused by the use of chewing material, whereas veterinary treatment due to a problem with chewing material was reported by 3.6 %. Chewing daily on soft household objects was observed in 2.5 % of dogs (other common objects for daily chewing: resting places 2.2 %, clothes/shoes 1.4 %); dogs up to one year of age did this more frequently (p < 0.001). Chewing on objects was not substantially related to reported motivation of the dog to play or the frequency of activities with the dog (all rs < 0.2), but was reported to occur in contexts that may cause negative emotional states such as leaving the dog alone (rs = 0.63, p < 0.001) or changes in routine activities (rs = 0.47, p < 0.001). The average reported frequency of provision of chewing material correlated positively (rs ≥ 0.2) with motivation of the dog to play, chewing on objects, human-dog play and calm activities such as petting. Dog owners think that chewing material is important for puppies and even more for adult dogs (p < 0.001). However, it remains to be investigated how motivated dogs are for chewing on different types of materials and whether chewing, as proposed by dog professionals, reduces stress. This seems particularly important for assessing the trade-off between risks and benefits of different chewing materials and its impact on dog welfare.

Comparison of Different Technologies for Soft Robotics Grippers.

Soft grippers have experienced a growing interest due to their considerable flexibility that allows them to grasp a variety of objects, in contrast to hard grippers, which are designed for a specific item. One of their most remarkable characteristics is the ability to manipulate soft objects without damaging them. This, together with their wide range of applications and the use of novels materials and technologies, renders them a very robust device. In this paper, we present a comparison of different technologies for soft robotics grippers. We fabricated and tested four grippers. Two use pneumatic actuation (the gripper with chambered fingers and the jamming gripper), while the other two employ electromechanical actuation (the tendon driver gripper and the gripper with passive structure). For the experiments, a group of twelve objects with different mechanical and geometrical properties have been selected. Furthermore, we analyzed the effect of the environmental conditions on the grippers, by testing each object in three different environments: normal, humid, and dusty. The aim of this comparative study is to show the different performances of different grippers tested under the same conditions. Our findings indicate that we can highlight that the mechanical gripper with a passive structure shows greater robustness.

Dual‐Responsive Soft Actuators with Integrated Sensing Function Based on 1T‐MoS2 Composite

Developing a multiresponsive and multifunctional soft actuator that can output mechanical deformation is crucial to the fields of soft robotics and wearable devices. Herein, a 2D metallic molybdenum disulfide (MoS2)‐based soft actuator with dual‐response and self‐sensing function is designed and fabricated. By using the outstanding photothermal property of 1T phase MoS2, good electrical property and network structure of carbon nanotubes (CNTs), hygroscopic expansion of paper, and thermal expansion of polyimide (PI), the MoS2‐based actuator can respond to external voltage and light stimulation and produce rapid and large bending deformation. In addition, the actuator can be used as a flexible strain sensor to realize real‐time sensing of bending deformation by using piezoresistive property of the MoS2–CNT composite film. Based on this soft actuator, a flexible mechanical gripper that can manipulate soft objects with irregular shape and intelligent wearable gloves that can automatically close to block the light irradiation are made. Furthermore, combined with the sensing feature of this MoS2‐based actuator, the gripper with integrated sensing function is also developed. These results indicate the great prospect of the MoS2‐based actuator in intelligent soft mechanical devices, robots, and wearable systems.

Extra-Soft Tactile Sensor for Sensitive Force/Displacement Measurement with High Linearity Based on a Uniform Strength Beam.

The soft sensing system has drawn huge enthusiasm for the application of soft robots and healthcare recently. Most of them possess thin-film structures that are beneficial to monitoring strain and pressure, but are unfavorable for measuring normal displacement with high linearity. Here we propose soft tactile sensors based on uniform-strength cantilever beams that can be utilized to measure the normal displacement and force of soft objects simultaneously. First, the theoretical model of the sensors is constructed, on the basis of which, the sensors are fabricated for testing their sensing characteristics. Next, the test results validate the constructed model, and demonstrate that the sensors can measure the force as well as the displacement. Besides, the self-fabricated sensor can have such prominent superiorities as follows—it is ultra-soft, and its equivalent stiffness is only 0.31 N·m−1 (approximately 0.4% of fat); it has prominent sensing performance with excellent linearity (R2 = 0.999), high sensitivity of 0.533 pF·mm−1 and 1.66 pF·mN−1 for measuring displacement and force; its detection limit is as low as 70 μm and 20 μN that is only one-tenth of the touch of a female fingertip. The presented sensor highlights a new idea for measuring the force and displacement of the soft objects with broad application prospects in mechanical and medical fields.

3D printing in surgical simulation: emphasized importance in the COVID-19 pandemic era

3D printing in surgical simulation: emphasized importance in the COVID-19 pandemic era