Valveless microliter combustion for densely packed arrays of powerful soft actuators

2021 ◽  
Vol 118 (39) ◽  
pp. e2106553118
Author(s):  
Ronald H. Heisser ◽  
Cameron A. Aubin ◽  
Ofek Peretz ◽  
Nicholas Kincaid ◽  
Hyeon Seok An ◽  
...  
Keyword(s):  
Tactile Stimulation ◽  
Exothermic Reaction ◽  
Tactile Display ◽  
Metal Electrodes ◽  
Pneumatic Actuators ◽  
Display Technology ◽  
Fluidic Actuators ◽  
Operational Frequency ◽  
Soft Actuators ◽  
Flame Behavior

Existing tactile stimulation technologies powered by small actuators offer low-resolution stimuli compared to the enormous mechanoreceptor density of human skin. Arrays of soft pneumatic actuators initially show promise as small-resolution (1- to 3-mm diameter), highly conformable tactile display strategies yet ultimately fail because of their need for valves bulkier than the actuators themselves. In this paper, we demonstrate an array of individually addressable, soft fluidic actuators that operate without electromechanical valves. We achieve this by using microscale combustion and localized thermal flame quenching. Precisely, liquid metal electrodes produce sparks to ignite fuel lean methane–oxygen mixtures in a 5-mm diameter, 2-mm tall silicone cylinder. The exothermic reaction quickly pressurizes the cylinder, displacing a silicone membrane up to 6 mm in under 1 ms. This device has an estimated free-inflation instantaneous stroke power of 3 W. The maximum reported operational frequency of these cylinders is 1.2 kHz with average displacements of ∼100 µm. We demonstrate that, at these small scales, the wall-quenching flame behavior also allows operation of a 3 × 3 array of 3-mm diameter cylinders with 4-mm pitch. Though we primarily present our device as a tactile display technology, it is a platform microactuator technology with application beyond this one.

A soft ring oscillator

2019 ◽  
Vol 4 (31) ◽  
pp. eaaw5496 ◽  
Author(s):  
Daniel J. Preston ◽  
Haihui Joy Jiang ◽  
Vanessa Sanchez ◽  
Philipp Rothemund ◽  
Jeff Rawson ◽  
...  
Keyword(s):  
Constant Pressure ◽  
Particle Separation ◽  
Schmitt Trigger ◽  
Ring Oscillator ◽  
System Level ◽  
Pressure Source ◽  
Pneumatic Actuators ◽  
System Parameters ◽  
Soft Actuators ◽  
Single Constant

Periodic actuation of multiple soft, pneumatic actuators requires coordinated function of multiple, separate components. This work demonstrates a soft, pneumatic ring oscillator that induces temporally coordinated periodic motion in soft actuators using a single, constant-pressure source, without hard valves or electronic controls. The fundamental unit of this ring oscillator is a soft, pneumatic inverter (an inverting Schmitt trigger) that switches between its two states (“on” and “off”) using two instabilities in elastomeric structures: buckling of internal tubing and snap-through of a hemispherical membrane. An odd number of these inverters connected in a loop produces the same number of periodically oscillating outputs, resulting from a third, system-level instability; the frequency of oscillation depends on three system parameters that can be adjusted. These oscillatory output pressures enable several applications, including undulating and rolling motions in soft robots, size-based particle separation, pneumatic mechanotherapy, and metering of fluids. The soft ring oscillator eliminates the need for hard valves and electronic controls in these applications.

Torsional Stiffness Improvement of a Soft Pneumatic Finger Using Embedded Skeleton

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Amin Lotfiani ◽  
Huichan Zhao ◽  
Zhufeng Shao ◽  
Xili Yi
Keyword(s):  
Torsional Stiffness ◽  
Good Precision ◽  
Pneumatic Actuators ◽  
Finite Element Approach ◽  
Grasping And Manipulation ◽  
Element Approach ◽  
Series Of Experiments ◽  
Soft Actuators ◽  
Compact Design ◽  
Rigid Skeleton

Abstract Silicone-based pneumatic actuators are among the most widely used soft actuators in adaptable fingers. However, due to the soft nature of silicone, the performance of these fingers is highly affected by the low torsional stiffness, which may cause failure in grasping and manipulation. To address this problem, a compact design is proposed by embedding a rigid skeleton into a soft pneumatic finger. A finite element approach with an analysical model is used to evaluate the performance of the fingers both with and without the skeleton. Then, a series of experiments is performed to study the bending motion and rigidity of the fingers. The results reveal that the skeleton increases the torsional stiffness of the finger up to 300%. Furthermore, the consistency with the experimental data indicates the good precision of the proposed modeling method. Finally, a two-finger hand is designed to evaluate the performance of the reinforced finger in reality. The grasp experiments illustrate that the hybrid finger with the skeleton is highly adaptable and can successfully grasp and manipulate heavy objects. Thus, a potential approach is proposed to improve the torsional stiffness of silicone-based pneumatic fingers while maintaining adaptability.

scholarly journals Rapid Design and Analysis of Microtube Pneumatic Actuators Using Line-Segment and Multi-Segment Euler–Bernoulli Beam Models

Micromachines ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 780 ◽  
Author(s):  
Myunggi Ji ◽  
Qiang Li ◽  
In Ho Cho ◽  
Jaeyoun Kim
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Line Segment ◽  
Beam Model ◽  
Element Analysis ◽  
Pneumatic Actuators ◽  
Design And Optimization ◽  
Rapid Design ◽  
The Finite Element Analysis ◽  
Soft Actuators

Soft material-based pneumatic microtube actuators are attracting intense interest, since their bending motion is potentially useful for the safe manipulation of delicate biological objects. To increase their utility in biomedicine, researchers have begun to apply shape-engineering to the microtubes to diversify their bending patterns. However, design and analysis of such microtube actuators are challenging in general, due to their continuum natures and small dimensions. In this paper, we establish two methods for rapid design, analysis, and optimization of such complex, shape-engineered microtube actuators that are based on the line-segment model and the multi-segment Euler–Bernoulli’s beam model, respectively, and are less computation-intensive than the more conventional method based on finite element analysis. To validate the models, we first realized multi-segment microtube actuators physically, then compared their experimentally observed motions against those obtained from the models. We obtained good agreements between the three sets of results with their maximum bending-angle errors falling within ±11%. In terms of computational efficiency, our models decreased the simulation time significantly, down to a few seconds, in contrast with the finite element analysis that sometimes can take hours. The models reported in this paper exhibit great potential for rapid and facile design and optimization of shape-engineered soft actuators.

Trial Development of Tactile display technology using MEMS technology

2016 ◽  
Vol 2016 (0) ◽  
pp. 1P1-19a5
Author(s):  
Junji SONE ◽  
Takehiro ADACHI ◽  
Yasuyoshi Matsumoto ◽  
Yoichi HOSHI
Keyword(s):  
Tactile Display ◽  
Mems Technology ◽  
Display Technology

scholarly journals Amplifying the response of soft actuators by harnessing snap-through instabilities

2015 ◽  
Vol 112 (35) ◽  
pp. 10863-10868 ◽  
Author(s):  
Johannes T. B. Overvelde ◽  
Tamara Kloek ◽  
Jonas J. A. D’haen ◽  
Katia Bertoldi
Keyword(s):  
Constant Volume ◽  
Next Generation ◽  
Active Elements ◽  
Fluidic Actuators ◽  
Numerical Tools ◽  
Large Motion ◽  
Soft Actuators

Soft, inflatable segments are the active elements responsible for the actuation of soft machines and robots. Although current designs of fluidic actuators achieve motion with large amplitudes, they require large amounts of supplied volume, limiting their speed and compactness. To circumvent these limitations, here we embrace instabilities and show that they can be exploited to amplify the response of the system. By combining experimental and numerical tools we design and construct fluidic actuators in which snap-through instabilities are harnessed to generate large motion, high forces, and fast actuation at constant volume. Our study opens avenues for the design of the next generation of soft actuators and robots in which small amounts of volume are sufficient to achieve significant ranges of motion.

Challenges in Development of Sub-Millimeter Resolution Thermo-Fluidic Actuator Based Wearable Tactile Display System for Blind Individuals

2011 ◽  
Author(s):  
Prakash C. R. J. Naidu ◽  
Ramesh Yechangunja ◽  
Andrea Prosperetti ◽  
Mandayam A. Srinivasan
Keyword(s):  
Spatial Resolution ◽  
Bubble Formation ◽  
Tactile Display ◽  
Switching Frequency ◽  
Display System ◽  
Prototype Development ◽  
Fluidic Actuators ◽  
Spatio Temporal ◽  
Human Finger ◽  
Blind Individuals

This paper presents the work conducted towards the realization of a novel tactile display system composed of miniature thermo-fluidic actuators. An application of the system particularly relevant to blind individuals is communication with computers through touch. The development of programmable spatio-temporal pattern of touch actuation based on bubble formation and vapor pressure has remarkable scope, not only because of the flexibility and wearability but also the high levels of motion amplitude and force of actuation not achieved so far by other means. The design specifications of the tactile display involved packaging of the miniature actuators in such a manner that the display can be conveniently attached at the tip of the human finger with desirable spatial resolution, and achieving the optimum force that can be felt through the human finger. However, there were challenges that were faced by the authors while miniaturizing the actuators for suitability in sub-millimeter spatial resolution desirable for the tactile display. The paper reports on the design, prototype development and experimental results and brings out the limitations along with possible solutions being pursued by the authors. The progressive efforts through fabrication and testing of different prototype thermo-fluidic actuators ranging from 3mm diameter bore to sub-millimeter sizes and the corresponding difficulties faced in the form of cooling requirements, hysteresis effects, and fabrication challenges are elucidated. The paper reports on packaging of actuators as an array of tiny tubes spaced as close as possible, and establishment of parameters, namely, amplitude of actuation and switching frequency, along with force generation adequate for tactile perception.

Development of Miniaturized Rubber Muscle Actuator Driven by Gas-Liquid Phase Change

2016 ◽  
Author(s):  
Tomonori Kato ◽  
Kazuki Sakuragi ◽  
Mingzhao Cheng ◽  
Ryo Kakiyama ◽  
Yuta Matsunaga ◽  
...  
Keyword(s):  
Control System ◽  
Liquid Phase ◽  
Frequency Response ◽  
Artificial Muscle ◽  
Phase Changes ◽  
Corner Frequency ◽  
Pi Control ◽  
Pneumatic Actuators ◽  
Frequency Responses ◽  
Soft Actuators

The goal of this study is to develop a miniaturized artificial muscle in which a tiny compressor can be installed. Pneumatic actuators, such as pneumatic artificial rubber muscles (PARMs), have been widely used in many industrial and robotic research applications because they are compact and lightweight. However, the compressors driving such actuators are relatively large. To solve this problem, the authors have been researching soft actuators driven by gas-liquid phase changes (GLPCs). In this study, a fixed chamber containing a constantan heater and fluorocarbon was used to generate pressure instead of a compressor. The pressure generation caused by the GLPC was confirmed, and a PARM contraction experiment was then conducted. Additionally, a PI control system was built to test the step and frequency responses of the actuator. A frequency response of up to 4.0 Hz was determined, and the corner frequency was found to be approximately 1.5 Hz. The size of the actuator was reduced by removing the chamber and installing the heater in the rubber muscle. A PARM driving experiment was conducted, and the performance of the PARM was evaluated. The miniaturized actuator consumes less power than the original actuator.

Vestibulo-tactile interactions regarding motion perception and eye movements in yaw

2005 ◽  
Vol 15 (3) ◽  
pp. 149-160
Author(s):  
Jelte E. Bos ◽  
Jan van Erp ◽  
Eric L. Groen ◽  
Hendrik-Jan van Veen
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Visual Information ◽  
Tactile Stimulation ◽  
Vertical Axis ◽  
Recovery Phase ◽  
Current Data ◽  
Tactile Display ◽  
Self Control ◽  
Movement Parameters

This paper shows that tactile stimulation can override vestibular information regarding spinning sensations and eye movements. However, we conclude that the current data do not support the hypothesis that tactile stimulation controls eye movements directly. To this end, twenty-four subjects were passively disoriented by an abrupt stop after an increase in yaw velocity, about an Earth vertical axis, up to 120°/s. Immediately thereafter, they had to actively maintain a stationary position despite a disturbance signal. Subjects wore a tactile display vest with 48 miniature vibrators, applied in different combinations with visual and vestibular stimuli. Their performance was quantified by RMS body velocity during self-control. Fast eye movement phases were analyzed by counting samples exceeding a velocity limit, slow phases by a novel method applying a first order model. Without tactile and visual information, subjects returned to a previous level of angular motion. Tactile stimulation decreased RMS self velocity considerably, though less than vision. No differences were observed between conditions in which the vest was active during the recovery phase only or during the disorienting phase as well. All effects of tactile stimulation found on the eye movement parameters could be explained by the vestibular stimulus.

Prototyping of Tactile display technology using MEMS technology-2

2018 ◽  
Vol 2018.9 (0) ◽  
pp. 31pm2PN102
Author(s):  
Junji Sone ◽  
Katsuhiko Ooizumi ◽  
Yasuyoshi Matsumoto ◽  
Yoji Yasuda ◽  
Yoich Hoshi
Keyword(s):  
Tactile Display ◽  
Mems Technology ◽  
Display Technology

scholarly journals Modelling and implementation of soft bio-mimetic turtle using echo state network and soft pneumatic actuators

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
MennaAllah Soliman ◽  
Mostafa A. Mousa ◽  
Mahmood A. Saleh ◽  
Mahmoud Elsamanty ◽  
Ahmed G. Radwan
Keyword(s):  
Orientation Angle ◽  
Motion Path ◽  
Echo State Network ◽  
Element Analysis ◽  
Pneumatic Actuators ◽  
Large Pressure ◽  
Inclination Angles ◽  
Maximum Root ◽  
Soft Actuators ◽  
Rotation Motion

AbstractAdvances of soft robotics enabled better mimicking of biological creatures and closer realization of animals’ motion in the robotics field. The biological creature’s movement has morphology and flexibility that is problematic deportation to a bio-inspired robot. This paper aims to study the ability to mimic turtle motion using a soft pneumatic actuator (SPA) as a turtle flipper limb. SPA’s behavior is simulated using finite element analysis to design turtle flipper at 22 different geometrical configurations, and the simulations are conducted on a large pressure range (0.11–0.4 Mpa). The simulation results are validated using vision feedback with respect to varying the air pillow orientation angle. Consequently, four SPAs with different inclination angles are selected to build a bio-mimetic turtle, which is tested at two different driving configurations. The nonlinear dynamics of soft actuators, which is challenging to model the motion using traditional modeling techniques affect the turtle’s motion. Conclusively, according to kinematics behavior, the turtle motion path is modeled using the Echo State Network (ESN) method, one of the reservoir computing techniques. The ESN models the turtle path with respect to the actuators’ rotation motion angle with maximum root-mean-square error of $$1.04 \times 10^{-11}$$ 1.04 × 10 - 11 . The turtle is designed to enhance the robot interaction with living creatures by mimicking their limbs’ flexibility and the way of their motion.

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