Cavatappi artificial muscles from drawing, twisting, and coiling polymer tubes

2021 ◽  
Vol 6 (53) ◽  
pp. eabd5383
Author(s):  
Diego R. Higueras-Ruiz ◽  
Michael W. Shafer ◽  
Heidi P. Feigenbaum
Keyword(s):  
Robotic Systems ◽  
Practical Implementation ◽  
Artificial Muscles ◽  
Specific Work ◽  
Bandwidth Efficiency ◽  
Initial Length ◽  
Thermally Activated ◽  
Linear Actuators ◽  
Twisted Tubes ◽  
Polymer Tubes

Compliant, biomimetic actuation technologies that are both efficient and powerful are necessary for robotic systems that may one day interact, augment, and potentially integrate with humans. To this end, we introduce a fluid-driven muscle-like actuator fabricated from inexpensive polymer tubes. The actuation results from a specific processing of the tubes. First, the tubes are drawn, which enhances the anisotropy in their microstructure. Then, the tubes are twisted, and these twisted tubes can be used as a torsional actuator. Last, the twisted tubes are helically coiled into linear actuators. We call these linear actuators cavatappi artificial muscles based on their resemblance to the Italian pasta. After drawing and twisting, hydraulic or pneumatic pressure applied inside the tube results in localized untwisting of the helical microstructure. This untwisting manifests as a contraction of the helical pitch for the coiled configuration. Given the hydraulic or pneumatic activation source, these devices have the potential to substantially outperform similar thermally activated actuation technologies regarding actuation bandwidth, efficiency, modeling and controllability, and practical implementation. In this work, we show that cavatappi contracts more than 50% of its initial length and exhibits mechanical contractile efficiencies near 45%. We also demonstrate that cavatappi artificial muscles can exhibit a maximum specific work and power of 0.38 kilojoules per kilogram and 1.42 kilowatts per kilogram, respectively. Continued development of this technology will likely lead to even higher performance in the future.

Miniaturized Pneumatic Artificial Muscles Actuating a Bio-Inspired Robot Hand

2013 ◽  
Author(s):  
Thomas E. Pillsbury ◽  
Ryan M. Robinson ◽  
Norman M. Wereley
Keyword(s):  
Degrees Of Freedom ◽  
Full Scale ◽  
Constitutive Relationship ◽  
Force Density ◽  
Human Hand ◽  
Artificial Muscles ◽  
Specific Work ◽  
Robotic Hand ◽  
Robot Hand ◽  
Pneumatic Artificial Muscles

Pneumatic artificial muscles (PAMs) are used in robotics applications for their light-weight design and superior static performance. Additional PAM benefits are high specific work, high force density, simple design, and long fatigue life. Previous use of PAMs in robotics research has focused on using “large,” full-scale PAMs as actuators. Large PAMs work well for applications with large working volumes that require high force and torque outputs, such as robotic arms. However, in the case of a compact robotic hand, a large number of degrees of freedom are required. A human hand has 35 muscles, so for similar functionality, a robot hand needs a similar number of actuators that must fit in a small volume. Therefore, using full scale PAMs to actuate a robot hand requires a large volume which for robotics and prosthetics applications is not feasible, and smaller actuators, such as miniature PAMs, must be used. In order to develop a miniature PAM capable of producing the forces and contractions needed in a robotic hand, different braid and bladder material combinations were characterized to determine the load stroke profiles. Through this characterization, miniature PAMs were shown to have comparably high force density with the benefit of reduced actuator volume when compared to full scale PAMs. Testing also showed that braid-bladder interactions have an important effect at this scale, which cannot be modeled sufficiently using existing methods without resorting to a higher-order constitutive relationship. Due to the model inaccuracies and the limited selection of commercially available materials at this scale, custom molded bladders were created. PAMs created with these thin, soft bladders exhibited greatly improved performance.

Carbon Fiber Based Twisted and Coiled Artificial Muscles (TCAMs) for Powered Ankle-Foot Orthoses (AFO)

2021 ◽  
Author(s):  
Parth Kotak ◽  
Jason Wilken ◽  
Kirsten Anderson ◽  
Caterina Lamuta
Keyword(s):  
Carbon Fiber ◽  
Low Cost ◽  
Input Voltage ◽  
Input Power ◽  
Artificial Muscles ◽  
Specific Work ◽  
Foot Orthoses ◽  
Ankle Foot Orthoses ◽  
Low Cost Manufacturing

Abstract Ankle foot orthoses (AFOs) control the position and motion of the ankle, compensate for weakness, and correct deformities. AFOs can be classified as passive or powered. Powered AFOs overcome the limitations of passive AFOs by adapting their performance to meet a variety of requirements. However, the actuators currently used to power AFOs are typically heavy, bulky, expensive, or limited to laboratory settings. Thus, there is a strong need for lightweight, inexpensive, and flexible actuators for powering AFOs. In this technical brief, Carbon Fiber/Silicone Rubber (CF/SR) Twisted and Coiled Artificial Muscles (TCAMs) are proposed as novel actuators for powered AFOs. CF/SR TCAMs can lift up to 12,600 times their weight with an input power of only 0.025 W cm-1 and are fabricated from inexpensive materials through a low-cost manufacturing process. Additionally, they can provide a specific work of 758 J kg-1 when an input voltage of 1.64 V cm-1 is applied. A mechanical characterization of CF/SR TCAMs in terms of length/tension, tension/velocity, and active-passive length/tension is presented, and results are compared with the performance of skeletal muscles. A gait analysis demonstrates that CF/SR TCAMs can provide the performance required to supplement lower limb musculature and replicate the gait cycle of a healthy subject. Therefore, the preliminary results provided in this brief are a stepping stone for a dynamic AFO powered by CF/SR TCAMs.

Model-Based Feedforward Control of a Robotic Manipulator With Pneumatic Artificial Muscles

2012 ◽  
Author(s):  
Ryan M. Robinson ◽  
Norman M. Wereley ◽  
Curt S. Kothera
Keyword(s):  
Control Algorithm ◽  
Controller Design ◽  
Feedforward Control ◽  
Artificial Muscles ◽  
Specific Work ◽  
Pneumatic Actuators ◽  
Precise Control ◽  
Model Based ◽  
Pneumatic Artificial Muscles ◽  
Dynamics Simulations

Pneumatic artificial muscles (PAMs) are lightweight, flexible actuators capable of higher specific work than comparably-sized hydraulic actuators at the same pressure and electric motors. PAMs are composed of an elastomeric bladder surrounded by a helically braided sleeve. Lightweight, compliant actuators are particularly desirable in portable, heavy-lift robotic systems intended for interaction with humans, such as those envisioned for patient assistance in hospitals and battlefield casualty extraction. However, smooth and precise control remains difficult because of nonlinearities in the dynamic response. The objective of this paper is to develop a control algorithm that satisfies accuracy and smooth motion requirements for a two degree-of-freedom manipulator actuated by pneumatic artificial muscles and intended for interaction with humans, such as lifting a human. This control strategy must be capable of responding to large, abrupt variations in payload weight over a high range of motion. In previous work, the authors detailed the design and construction of a proof-of-concept PAM-based manipulator. The present work investigates the feasibility of combining output feedback using proportional-integral-derivative control or fuzzy logic control with model-based feedforward compensation to achieve improved closed-loop performance. The model upon which the controller is based incorporates the internal airflow dynamics, the geometric parameters of the pneumatic actuators, and the arm dynamics. Simulations were performed in order to validate the control algorithm, guide controller design, and predict optimal gains. Using real-time interface software and hardware, the controller was implemented and experimentally tested on the manipulator. Performance was evaluated for several trajectories, and different payload weights. The effect of varying the feedforward gain was also analyzed. Model refinement further improved performance.

Contractile Pneumatic Artificial Muscle Configured to Generate Extension

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Benjamin K. S. Woods ◽  
Shane M. Boyer ◽  
Erica G. Hocking ◽  
Norman M. Wereley ◽  
Curt S. Kothera
Keyword(s):  
Compressive Loading ◽  
Compressive Force ◽  
Artificial Muscle ◽  
Specific Power ◽  
Artificial Muscles ◽  
Specific Work ◽  
Operational Characteristics ◽  
Pneumatic Artificial Muscles ◽  
High Specific Power ◽  
Internal Mechanism

Pneumatic artificial muscles (PAMs) are comprised of an elastomeric bladder surrounded by a braided mesh sleeve. When the bladder is inflated, the actuator may either contract or extend axially, with the direction of motion dependent on the orientation of the fibers in the braided sleeve. Contractile PAMs have excellent actuation characteristics, including high specific power, specific work, and power density. Unfortunately, extensile PAMs exhibit much reduced blocked force, and are prone to buckling under axial compressive loading. For applications in which extensile motion and compressive force are desired, the push-PAM actuator introduced here exploits the operational characteristics of a contractile PAM, but changes the direction of motion and force by employing a simple internal mechanism using no gears or pulleys. Quasi-static behavior of the push-PAM was compared to a contractile PAM for a range of operating pressures. Based on these data, the push-PAM actuator can achieve force and stroke comparable to a contractile PAM tested under the same conditions.

2A1-B04 Development of a Biomimetic Robotic Arm Driven by Electromagnetic Linear Actuators for Artificial Muscles

2010 ◽  
Vol 2010 (0) ◽  
pp. _2A1-B04_1-_2A1-B04_4
Author(s):  
Yoshihiro NAKATA ◽  
Fuminao OBAYASHI ◽  
Katsuhiro HIRATA ◽  
Hiroshi ISHIGURO
Keyword(s):  
Robotic Arm ◽  
Artificial Muscles ◽  
Linear Actuators

Ionic Polymer Conductor Nano-Composites as Distributed Nanosensors, Nanoactuators and Artificial Muscles - A Review

2006 ◽  
Vol 949 ◽  
Author(s):  
Mohsen Shahinpoor
Keyword(s):  
Musical Instruments ◽  
Nano Composites ◽  
Artificial Muscles ◽  
Modeling And Simulations ◽  
Data Glove ◽  
Ionic Polymer ◽  
Force Optimization ◽  
Linear Actuators ◽  
Biomimetic Robotic Fish ◽  
Manufacturing Techniques

ABSTRACTBasic recent results, properties and characteristics of ionic polymer conductor nano-composites (IPCNC) as biomimetic distributed nanosensors, nanoactuators and artificial muscles are briefly discussed in this paper. Some fundamental considerations on biomimetic distributed nanosensing and nanoactuation are first presented and then expanded to cover some recent advances in manufacturing techniques, force optimization, 3-D fabrication of IPMC's, recent modeling and simulations, sensing and transduction and product development. This paper also covers some recent industrial and medical applications including a multi-fingered grippers (macro, micro, nano), biomimetic robotic fish and caudal fin actuators, diaphragm micropump, multi-string musical instruments, linear actuators made with IPMNC's, IPMNC-based data glove and attire, IPMNC-based heart compression/assist devices and systems, wing flapping flying system made with IPMNC's and a host of others.

scholarly journals Digital light processing of liquid crystal elastomers for self-sensing artificial muscles

2021 ◽  
Vol 7 (30) ◽  
pp. eabg3677
Author(s):  
Shuo Li ◽  
Hedan Bai ◽  
Zheng Liu ◽  
Xinyue Zhang ◽  
Chuqi Huang ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Optical Transition ◽  
Orientational Order ◽  
Weight Ratio ◽  
Great Promise ◽  
Artificial Muscles ◽  
Specific Work ◽  
Digital Light Processing ◽  
Stimuli Responsive Polymers ◽  
Liquid Crystal Elastomers

Artificial muscles based on stimuli-responsive polymers usually exhibit mechanical compliance, versatility, and high power-to-weight ratio, showing great promise to potentially replace conventional rigid motors for next-generation soft robots, wearable electronics, and biomedical devices. In particular, thermomechanical liquid crystal elastomers (LCEs) constitute artificial muscle-like actuators that can be remotely triggered for large stroke, fast response, and highly repeatable actuations. Here, we introduce a digital light processing (DLP)–based additive manufacturing approach that automatically shear aligns mesogenic oligomers, layer-by-layer, to achieve high orientational order in the photocrosslinked structures; this ordering yields high specific work capacity (63 J kg−1) and energy density (0.18 MJ m−3). We demonstrate actuators composed of these DLP printed LCEs’ applications in soft robotics, such as reversible grasping, untethered crawling, and weightlifting. Furthermore, we present an LCE self-sensing system that exploits thermally induced optical transition as an intrinsic option toward feedback control.

scholarly journals New twist on artificial muscles

2016 ◽  
Vol 113 (42) ◽  
pp. 11709-11716 ◽  
Author(s):  
Carter S. Haines ◽  
Na Li ◽  
Geoffrey M. Spinks ◽  
Ali E. Aliev ◽  
Jiangtao Di ◽  
...  
Keyword(s):  
Artificial Muscle ◽  
Polymer Fibers ◽  
Artificial Muscles ◽  
Specific Work ◽  
New Class ◽  
Hysteretic Performance ◽  
Potential Applications ◽  
Thermally Actuated ◽  
Sewing Threads ◽  
Response To Temperature

Lightweight artificial muscle fibers that can match the large tensile stroke of natural muscles have been elusive. In particular, low stroke, limited cycle life, and inefficient energy conversion have combined with high cost and hysteretic performance to restrict practical use. In recent years, a new class of artificial muscles, based on highly twisted fibers, has emerged that can deliver more than 2,000 J/kg of specific work during muscle contraction, compared with just 40 J/kg for natural muscle. Thermally actuated muscles made from ordinary polymer fibers can deliver long-life, hysteresis-free tensile strokes of more than 30% and torsional actuation capable of spinning a paddle at speeds of more than 100,000 rpm. In this perspective, we explore the mechanisms and potential applications of present twisted fiber muscles and the future opportunities and challenges for developing twisted muscles having improved cycle rates, efficiencies, and functionality. We also demonstrate artificial muscle sewing threads and textiles and coiled structures that exhibit nearly unlimited actuation strokes. In addition to robotics and prosthetics, future applications include smart textiles that change breathability in response to temperature and moisture and window shutters that automatically open and close to conserve energy.

Design and testing of a high-specific work actuator using miniature pneumatic artificial muscles

2012 ◽  
Vol 23 (3) ◽  
pp. 365-378 ◽  
Author(s):  
Robert D. Vocke ◽  
Curt S. Kothera ◽  
Anirban Chaudhuri ◽  
Benjamin K.S. Woods ◽  
Norman M. Wereley
Keyword(s):  
Angular Rate ◽  
Active Material ◽  
Small Scale ◽  
Artificial Muscles ◽  
Prototype System ◽  
Specific Work ◽  
Pneumatic Actuators ◽  
Actuation System ◽  
Angular Deflection ◽  
Pneumatic Artificial Muscles

Micro-air vehicle (MAV) development is moving toward smaller and more capable platforms to enable missions such as indoor reconnaissance. This miniaturization creates challenging constraints on volume and energy generation/storage for all systems onboard. Actuator technologies must also address these miniaturization goals. Much research has focused on active material systems, such as piezoelectric materials and synthetic jets, but these advanced technologies have specific, but limited, capability. Conventional servo technology has also encountered concerns over miniaturization. Motivation has thus been established to develop a small-scale actuation technology prototype based on pneumatic artificial muscles, which are known for their lightweight, high-output, and low-pressure operation. The miniature actuator provides bidirectional control capabilities for a range of angles, rates, and loading conditions. Problems addressed include the scaling of the pneumatic actuators and design of a mechanism to adjust the kinematic load-stroke profile to suit the pneumatic actuators. The kinematics of the actuation system was modeled, and a number of bench-top configurations were fabricated, assembled, and experimentally characterized. Angular deflection and angular rate output of the final bench-top prototype system are presented, showing an improvement over conventional servo motors used in similar applications, especially in static or low-frequency operation.

Promising Developments in Marine Applications With Artificial Muscles: Electrodeless Artificial Cilia Microfibers

2016 ◽  
Vol 50 (5) ◽  
pp. 24-34 ◽  
Author(s):  
Kwang J. Kim ◽  
Viljar Palmre ◽  
Tyler Stalbaum ◽  
Taeseon Hwang ◽  
Qi Shen ◽  
...  
Keyword(s):  
Electric Field ◽  
Circular Cross Section ◽  
Robotic Systems ◽  
Small Scale ◽  
Artificial Muscles ◽  
Metal Composite ◽  
Initial Development ◽  
Research Attention ◽  
Ionic Polymer ◽  
Artificial Cilia

AbstractIonic polymer-metal composite artificial muscles have received great research attention in the development of robotic manipulators, advanced medical devices, and underwater propulsors, such as artificial fish fins. This is due to their unique properties of large deformation, fast dynamic response, low-power requirements, and the ability to operate in aquatic environments. Recently, locomotion of biological cells and microorganisms through unique motion of cilium (flagellum) has received great interest in the field of biomimetic robotics. It is envisioned that artificial cilia can be an effective strategy for maneuvering and sensing in small-scale bioinspired robotic systems. However, current actuators used for driving the robots are typically rigid, bulky in mechanism and electronics requirements producing some acoustic signatures, and difficult to miniaturize. Herein, we report biomimetic, wirelessly driven, electroactive polymer (EAP) microfibers that actuate in an aqueous medium when subjected to an external electric field of <5 V/mm, which can be realized to create cilia-based robotic systems for aquatic applications. Initial development and manufacturing of these systems is presented in this paper. The EAP fibers are fabricated from ionic polymer precursor resin through melt-drawing process and have a circular cross-section with a diameter of 30‐70 μm. When properly activated and subjected to an electric field with switching polarity, the EAP fibers exhibit cyclic actuation with adequate response time (0.05‐5 Hz). The experimental results are presented and discussed to demonstrate the performance and feasibility of biomimetic cilia-based microactuators. Prospective bioinspired applications of the artificial muscle cilia-based system in marine operations are also discussed.

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