The ability to achieve simultaneous intrinsic deformation with fast response in commercially available materials that can safely contact skin continues to be an unresolved challenge for artificial ...actuating materials. Rather than using a microporous structure, here we show an ambient-driven actuator that takes advantage of inherent nanoscale molecular channels within a commercial perfluorosulfonic acid ionomer (PFSA) film, fabricated by simple solution processing to realize a rapid response, self-adaptive, and exceptionally stable actuation. Selective patterning of PFSA films on an inert soft substrate (polyethylene terephthalate film) facilitates the formation of a range of different geometries, including a 2D (two-dimensional) roll or 3D (three-dimensional) helical structure in response to vapor stimuli. Chemical modification of the surface allowed the development of a kirigami-inspired single-layer actuator for personal humidity and heat management through macroscale geometric design features, to afford a bilayer stimuli-responsive actuator with multicolor switching capability.
This paper focuses on design, fabrication and characterization of a biomimetic, compact, low-cost and lightweight 3D printed humanoid hand (TCP Hand) that is actuated by twisted and coiled polymeric ...(TCP) artificial muscles. The TCP muscles were recently introduced and provided unprecedented strain, mechanical work, and lifecycle (Haines et al 2014 Science 343 868-72). The five-fingered humanoid hand is under-actuated and has 16 degrees of freedom (DOF) in total (15 for fingers and 1 at the palm). In the under-actuated hand designs, a single actuator provides coupled motions at the phalanges of each finger. Two different designs are presented along with the essential elements consisting of actuators, springs, tendons and guide systems. Experiments were conducted to investigate the performance of the TCP muscles in response to the power input (power magnitude, type of wave form such as pulsed or square wave, and pulse duration) and the resulting actuation stroke and force generation. A kinematic model of the flexor tendons was developed to simulate the flexion motion and compare with experimental results. For fast finger movements, short high-power pulses were employed. Finally, we demonstrated the grasping of various objects using the humanoid TCP hand showing an array of functions similar to a natural hand.
A soft actuator is an essential component in a soft robot that enables it to perform complex movements by combining different fundamental motion modes. One type of soft actuator that has received ...significant attention is the twisted and coiled polymer artificial muscle (TCP actuator). Despite many recent advancements in TCP actuator research, its use as an extensile actuator is less common in the literature. This works introduces the concept of using TCP actuators as thermal-driven extensile actuators for robotics applications. The low-profile actuator can be easily fabricated to offer two unique deformation capabilities. Results from the characterization indicate that extensile actuators, made with various rod diameters and under different load conditions, display remarkable elongation deformation. Additionally, a proof-of-concept soft-earthworm robot was developed to showcase the potential application of the extensile actuator and to demonstrate the benefits of combining different types of motion modes.
An affordable, highly articulated, child-size humanoid robot could potentially be used for various purposes, widening the design space of humanoids for further study. Several findings indicated that ...normal children and children with autism interact well with humanoids. This paper presents a child-sized humanoid robot (HBS-1) intended primarily for children’s education and rehabilitation. The design approach is based on the design for manufacturing (DFM) and the design for assembly (DFA) philosophies to realize the robot fully using additive manufacturing. Most parts of the robot are fabricated with acrylonitrile butadiene styrene (ABS) using rapid prototyping technology. Servomotors and shape memory alloy actuators are used as actuating mechanisms. The mechanical design, analysis and characterization of the robot are presented in both theoretical and experimental frameworks.
Purpose To evaluate the application of the medial sural artery perforator flap (MSAPF) aided by preoperative ultrasonic perforator localization for postsurgical reconstruction of oral carcinoma. ...Materials and Methods From November 2013 to August 2014, 25 patients with oral carcinoma underwent postsurgical reconstruction after oral carcinoma resection using MSAPFs. To explore and locate the perforators, preoperative vascular ultrasound localization was used to find the MSAPs. The number and location of the perforators, length of the vascular pedicle, and thickness of the MSAPF were measured. Thirty-eight patients who underwent reconstruction with a radial forearm flap (RFF) and 21 patients who underwent reconstruction with an anterolateral thigh flap (ALTF) were selected for comparison. Results The number of MSAPs ranged from 1 to 4, and 52 perforators were found accurately using preoperative ultrasonic localization (92.86%). The distance from the perforator to the popliteal crease ranged from 6.2 to 17.1 cm (10.70 ± 2.31 cm); the distance from the perforator to the midline of the back of the calf ranged from 0.1 to 3.5 cm (1.83 ± 0.81 cm); and the pedicle length ranged from 6.8 to 12.5 cm (10.14 ± 1.51 cm). Compared with the RFF, and ALTF, the thickness, postoperative oral sensation, and function of the MSAPF were similar to those of the RFF but better than those of the ALTF. In appearance and function of the donor site, the MSAPF was similar to the ALTF, but better than the RFF. Conclusion The MSAPF is a good alternative for postsurgical reconstruction of oral carcinoma because of its anatomic structural stability, suitable thickness, minimal donor-site scar, and ideal functional recovery after surgery. Preoperative vascular ultrasonic localization is a feasible and advantageous method for preoperative mapping of the MSAP because of its high accuracy.
Twisted and coiled polymer (TCP) muscles are recently introduced thermal actuators that offer unprecedented performance. Merits such as low cost, high load capacity, and light weight make them ...suitable for robotics and biomechanics. Using these actuators for practical applications requires an understanding of their behavior in response to the electrical input. In this article, a physics-based model is proposed to predict the displacement of TCP muscles with respect to the input electrical energy and the applied load. We quantified effects of temperature on coefficients of thermal expansion and elastic modulus. It is found that the change of properties above the polymer glass transition temperature has a crucial effect on the actuator performance. A stiffness model is proposed, which include the effect of change in geometry and elastic modulus of TCP muscles. Finally, a set of equations for simulating the TCP muscles are formulated in discrete time representation. The model is generalized for the two-ply case by considering the difference in geometry. The accuracy of the model is tested in comparison with experimental data, acquired at several actuation levels and applied loads, for both one-ply and two-ply configurations. The model showed a good accuracy in predicting the behavior of the actuators both in temperature and displacement. Our model was also compared with other representative models and revealed improvement in the prediction accuracy.
Perpendicular recording media technology faces limitation in the writability of media with high anisotropy. Therefore, alternative methods are sought to overcome this problem. Heat-assisted magnetic ...recording may give rise to high areal densities, but the technological process will take time. We have studied methods to improve the writability in perpendicular recording media using crystalline soft underlayer (C-SUL) materials with fcc(111) texture. One of the recording media designs consists of a simple insertion of C-SUL material between the nonmagnetic intermediate layers, thus providing a path for magnetic flux during the writing. In the alternative methods, part of the nonmagnetic intermediate layer material was replaced with C-SUL material. Overwrite improvement was observed in both the cases, indicating that the C-SUL material will play a major role in improving writability in recording media.
The musculoskeletal system (MS) is essential for the movements of biological systems. Inspired by this natural structure, several attempts are made to create a synthetic MS. However, one of the ...challenges in developing an artificial MS for biomimetic robots is the lack of a high‐performance, low‐cost, light‐weight, and compact artificial muscle. In this Communication, a novel twisted and coiled artificial muscle is demonstrated, which is a promising actuator for the development of the artificial MS. The new muscle is made by twisting a nylon 6 fishing line precursor fiber and wrapping with a very thin (80 µm diameter) resistance wire. The resistance wire is not twisted during twist insertion of the polymer, which is very important for the performance of the muscle. The new muscle termed TCPNCFL is integrated in a 3D printed ball‐and‐socket‐based artificial MS. Characterization results show a remarkable tensile actuation (53% strain provided at 1.69 MPa for an input current of 0.22 A). Furthermore, a bioinspired design and fabrication of the synthetic MS is illustrated incorporating antagonistic pairs capable of reaching a bending angle of 20° within 1 s. These actuators can potentially be used in other soft robots, prosthetics, and orthotics advancing the progress in the area.
A new artificial muscle consisting of a very thin wire that is not twisted with the precursor fiber is demonstrated. A remarkable tensile actuation (53% strain under 1.69 MPa load for an input current of 0.22 A) and a bio‐inspired musculoskeletal system are demonstrated. The muscle can potentially be used in other soft robots, prosthetics, and orthotics.
Forkhead box f1 (FoxF1), a transcription factor, was implicated in lung development. However, the molecular mechanism of FoxF1 in lung injury, specifically in injury caused by paraquat (PQ), one of ...the most frequently used herbicides, is unknown. Accordingly, we performed this study to investigate whether FoxF1 attenuates PQ-induced lung injury and to determine the possible mechanism.
We used PQ-treated Beas-2B cells to measure the expression of FoxF1. Later, ChIP-qPCR was applied to detect the levels of histone acetylation in cells, followed by the validation of the relationship between histone deacetylase-2 (HDAC2) and FoxF1. Subsequently, the correlation between FoxF1 and microRNA (miR)-342 and the downstream mechanism of miR-342 were evaluated by bioinformatics analysis. The apoptosis and the content of reactive oxygen species (ROS) in PQ-treated cells were detected to evaluate the roles of HDAC2, FoxF1 and miR-342 in vitro. Finally, a rat model was developed to evaluate the effects of HDAC2, miR-342 and Krüppel-like factor 5 (KLF5) on PQ-induced lung injury in vivo.
PQ treatment significantly enhanced FoxF1 promoter deacetylation, thereby inhibiting FoxF1 expression. After inhibition of HDAC2 activity, apoptosis and oxidative stress induced by PQ were significantly reversed. Nevertheless, further inhibition of miR-342 or overexpression of KLF5 promoted apoptosis and oxidative stress induced by PQ, and IκB/NF-κB p65 signaling was significantly activated after PQ treatment.
PQ treatment inhibited miR-342 expression by promoting HDAC2-induced deacetylation of the FoxF1 promoter, thereby promoting KLF5 expression and the IκB/NF-κB p65 signaling activation, and finally exacerbating PQ-induced lung injury in rats.
•PQ promotes HDAC2 to repress FoxF1 transcription through deacetylation.•HDAC2 inhibitor enhances FoxF1 level and attenuates PQ-induced Beas-2B apoptosis.•FoxF1 inhibits KLF5 and IκB/NF-κB p65 via transcriptional activation of miR-342.•miR-342 inhibitor or oe-KLF5 blocks the effect of HDAC2 inhibitor on Beas-2B cells.•Activated IκB/NF-κB p65 weakens the effect of HDAC2 inhibitor on Beas-2B cells.
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