scholarly journals Modeling and Simulation of Robotic Finger Powered by Nylon Artificial Muscles

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Lokesh Saharan ◽  
Lianjun Wu ◽  
Yonas Tadesse
Keyword(s):  
High Performance ◽  
Electrical Power ◽  
Simulated Data ◽  
Artificial Muscle ◽  
Power Input ◽  
Artificial Muscles ◽  
Robotic Hand ◽  
Finger Motion ◽  
Angular Displacements ◽  
Measured Input

Abstract A robotic finger actuated by novel artificial muscles known as twisted and coiled polymer (TCP) muscles has been proposed as an inexpensive, yet high-performance component of a robotic hand in recent years. In this paper, the Euler–Lagrangian method coupled with an electro-thermo-mechanical model-based transfer function was used for the analysis of finger joints in the hand. Experiments were performed at three power magnitudes provided to the TCP muscles, and the output angular displacements of the index finger subtended corresponding to the power levels were measured. The measured input and output parameters were used for system identification. To elucidate how the new artificial muscle influences the finger motion, two types of numerical simulations were performed: force input simulation (FIS) using measured force as an input and power input simulation (PIS) using measured electrical power as an input. Results were quantified statistically, and the simulated data were compared with the experimental results. Sensitivity analysis was also presented to understand the effect of the mechanical properties on the system. This model will help in understanding the effect of the TCP muscles and other similar smart actuators on the dynamics of the robotic finger.

The Effects of Nylon Polymer Threads on Strain-Loading Hysteresis Behavior of Supercoiled Polymer (SCP) Artificial Muscles

2019 ◽  
Author(s):  
Revanth Konda ◽  
Jun Zhang
Keyword(s):  
Thermal Activation ◽  
Experimental Validation ◽  
Linear Models ◽  
Artificial Muscle ◽  
Power Input ◽  
Artificial Muscles ◽  
Helical Spring ◽  
Spring Model ◽  
Actuation Mechanism ◽  
Proposed Model

Abstract Supercoiled polymers (SCP) actuator, as a recently discovered artificial muscle, has attracted a lot of attention as a compliant and compact actuation mechanism. SCP actuators can be fabricated from nylon polymer threads, and generates up to 20% strain under thermal activation. A common challenge, however, is to accurately and efficiently estimate the performance of SCP actuators considering their significant hysteresis among loading, strain, and power input. Previous studies adopted either linear models that failed to capture the hysteresis or phenomenological models that required tedious procedures for identification and implementation. In this paper, a physics-inspired model is presented to efficiently capture and estimate SCP actuators’ strain – loading hysteresis by analyzing the properties of nylon threads from which they are fabricated. The strains of SCP actuators are found to be linear to that of the nylon threads under the same loading conditions. An efficient approach is proposed to characterize and estimate the strain – loading hysteresis of SCP actuators fabricated with different numbers of nylon threads. A helical spring model is adopted to obtain the stiffness of SCP actuators with different configurations. Experimental validation involving two-ply, four-ply, and six-ply nylon threads and SCP actuators are provided to confirm the effectiveness of the proposed model.

Actuation of untethered pneumatic artificial muscles and soft robots using magnetically induced liquid-to-gas phase transitions

2020 ◽  
Vol 5 (41) ◽  
pp. eaaz4239 ◽  
Author(s):  
Seyed M. Mirvakili ◽  
Douglas Sim ◽  
Ian W. Hunter ◽  
Robert Langer
Keyword(s):  
Phase Transition ◽  
Gas Phase ◽  
High Performance ◽  
Artificial Muscle ◽  
Artificial Muscles ◽  
Peak Strain ◽  
Soft Robots ◽  
Robotic Arms ◽  
Actuation Mechanism ◽  
Pneumatic Artificial Muscles

Pneumatic artificial muscles have been widely used in industry because of their simple and relatively high-performance design. The emerging field of soft robotics has also been using pneumatic actuation mechanisms since its formation. However, these actuators/soft robots often require bulky peripheral components to operate. Here, we report a simple mechanism and design for actuating pneumatic artificial muscles and soft robotic grippers without the use of compressors, valves, or pressurized gas tanks. The actuation mechanism involves a magnetically induced liquid-to-gas phase transition of a liquid that assists the formation of pressure inside the artificial muscle. The volumetric expansion in the liquid-to-gas phase transition develops sufficient pressure inside the muscle for mechanical operations. We integrated this actuation mechanism into a McKibben-type artificial muscle and soft robotic arms. The untethered McKibben artificial muscle generated actuation strains of up to 20% (in 10 seconds) with associated work density of 40 kilojoules/meter3, which favorably compares with the peak strain and peak energy density of skeletal muscle. The untethered soft robotic arms demonstrated lifting objects with an input energy supply from only two Li-ion batteries.

scholarly journals Constructing Large-Scale Genetic Maps Using an Evolutionary Strategy Algorithm

Genetics ◽  
2003 ◽  
Vol 165 (4) ◽  
pp. 2269-2282
Author(s):  
D Mester ◽  
Y Ronin ◽  
D Minkov ◽  
E Nevo ◽  
A Korol
Keyword(s):  
Discrete Optimization ◽  
High Performance ◽  
Large Scale ◽  
Simulated Data ◽  
Real Data ◽  
Genetic Maps ◽  
Chromosome 1 ◽  
Evolutionary Strategy ◽  
Group A ◽  
The One

Abstract This article is devoted to the problem of ordering in linkage groups with many dozens or even hundreds of markers. The ordering problem belongs to the field of discrete optimization on a set of all possible orders, amounting to n!/2 for n loci; hence it is considered an NP-hard problem. Several authors attempted to employ the methods developed in the well-known traveling salesman problem (TSP) for multilocus ordering, using the assumption that for a set of linked loci the true order will be the one that minimizes the total length of the linkage group. A novel, fast, and reliable algorithm developed for the TSP and based on evolution-strategy discrete optimization was applied in this study for multilocus ordering on the basis of pairwise recombination frequencies. The quality of derived maps under various complications (dominant vs. codominant markers, marker misclassification, negative and positive interference, and missing data) was analyzed using simulated data with ∼50-400 markers. High performance of the employed algorithm allows systematic treatment of the problem of verification of the obtained multilocus orders on the basis of computing-intensive bootstrap and/or jackknife approaches for detecting and removing questionable marker scores, thereby stabilizing the resulting maps. Parallel calculation technology can easily be adopted for further acceleration of the proposed algorithm. Real data analysis (on maize chromosome 1 with 230 markers) is provided to illustrate the proposed methodology.

Electrostatic bellow muscle actuators and energy harvesters that stack up

2021 ◽  
Vol 6 (51) ◽  
pp. eaaz5796
Author(s):  
I. D. Sîrbu ◽  
G. Moretti ◽  
G. Bortolotti ◽  
M. Bolignari ◽  
S. Diré ◽  
...  
Keyword(s):  
High Performance ◽  
High Reliability ◽  
Low Cost ◽  
Artificial Muscle ◽  
Pressure Head ◽  
Robotic Systems ◽  
Maximum Pressure ◽  
Term Operation ◽  
Energy Harvesters ◽  
Out Of Plane

Future robotic systems will be pervasive technologies operating autonomously in unknown spaces that are shared with humans. Such complex interactions make it compulsory for them to be lightweight, soft, and efficient in a way to guarantee safety, robustness, and long-term operation. Such a set of qualities can be achieved using soft multipurpose systems that combine, integrate, and commute between conventional electromechanical and fluidic drives, as well as harvest energy during inactive actuation phases for increased energy efficiency. Here, we present an electrostatic actuator made of thin films and liquid dielectrics combined with rigid polymeric stiffening elements to form a circular electrostatic bellow muscle (EBM) unit capable of out-of-plane contraction. These units are easy to manufacture and can be arranged in arrays and stacks, which can be used as a contractile artificial muscle, as a pump for fluid-driven soft robots, or as an energy harvester. As an artificial muscle, EBMs of 20 to 40 millimeters in diameter can exert forces of up to 6 newtons, lift loads over a hundred times their own weight, and reach contractions of over 40% with strain rates over 1200% per second, with a bandwidth over 10 hertz. As a pump driver, these EBMs produce flow rates of up to 0.63 liters per minute and maximum pressure head of 6 kilopascals, whereas as generator, they reach a conversion efficiency close to 20%. The compact shape, low cost, simple assembling procedure, high reliability, and large contractions make the EBM a promising technology for high-performance robotic systems.

Geometric Analysis and Synthesis of the Metamorphic Robotic Hand

2006 ◽  
Vol 129 (11) ◽  
pp. 1191-1197 ◽  
Author(s):  
Jian S. Dai ◽  
Delun Wang
Keyword(s):  
Differential Geometry ◽  
Geometric Analysis ◽  
Robotic Hand ◽  
Traditional Structure ◽  
Curve Approximation ◽  
Analysis And Synthesis ◽  
Finger Motion ◽  
The Relationship ◽  
Robotic Fingers

This paper presents a novel robotic hand with a metamorphic palm which changes the traditional structure of a robotic hand. Based on this new hand structure, the paper investigates motion of the robotic fingers with respect to the palm by presenting finger operation planes and by revealing the relationship between finger motion and palm motion. The study presents the normals of the finger operation planes as a function of the input angles of the palm and uses these normals to relate finger motion to palm motion. This leads to the coaxial condition of the finger-palm relationship that is then converted to the coplanar condition of normals of all finger operation planes. The condition is then used to generate a coupler trajectory, and the iterative trajectory fitting and curve approximation are used for synthesis of palm links, leading to differential geometry based synthesis of angular lengths of the metamorphic palm.

Macroporous smart gel based on pH-sensitive polyacrylic polymer for the development of large size artificial muscle with linear contraction

Soft Matter ◽  
2021 ◽  
Author(s):  
Vincent Mansard
Keyword(s):  
Soft Matter ◽  
Artificial Muscle ◽  
Ph Sensitive ◽  
Artificial Muscles ◽  
Linear Contraction ◽  
Large Size ◽  
Polyacrylic Polymer ◽  
The Revolution

The physics of soft matter can contribute to the revolution in robotics and medical prostheses.These two fields requires the development of artificial muscles with behavior close to the biologicalmuscle. Today,...

scholarly journals Theoretical Comparison of McKibben-Type Artificial Muscle and Novel Straight-Fiber-Type Artificial Muscle

2011 ◽  
Vol 5 (4) ◽  
pp. 544-550 ◽  
Author(s):  
Hiroki Tomori ◽  
◽  
Taro Nakamura
Keyword(s):  
Steady State ◽  
Dynamic Characteristic ◽  
Fiber Type ◽  
Human Life ◽  
Artificial Muscle ◽  
Artificial Muscles ◽  
Contraction Rate ◽  
Theoretical Comparison ◽  
Straight Fiber ◽  
Force Characteristics

Robots have entered human life, and closer relationships are being formed between humans and robots. It is desirable that these robots be flexible and lightweight. With this as our goal, we have developed an artificial muscle actuator using straight-fiber-type artificial muscles derived from the McKibben-type muscles, which have excellent contraction rate and force characteristics. In this study, we compared the steady state and dynamic characteristic of straightfiber-type and McKibben-type muscles and verified the usefulness of straight-fiber-type muscles.

scholarly journals Phase transformation-driven artificial muscle mimics the multifunctionality of avian wing muscle

2021 ◽  
Vol 18 (184) ◽  
Author(s):  
Pedro B. C. Leal ◽  
Marcela Cabral-Seanez ◽  
Vikram B. Baliga ◽  
Douglas L. Altshuler ◽  
Darren J. Hartl
Keyword(s):  
Skeletal Muscle ◽  
Mechanical Performance ◽  
Dynamic Control ◽  
Artificial Muscle ◽  
Bipedal Walking ◽  
Artificial Muscles ◽  
Operational Conditions ◽  
Leg Muscles ◽  
Engineered Systems ◽  
Electrical Stimuli

Skeletal muscle provides a compact solution for performing multiple tasks under diverse operational conditions, a capability lacking in many current engineered systems. Here, we evaluate if shape memory alloy (SMA) components can serve as artificial muscles with tunable mechanical performance. We experimentally impose cyclic stimuli, electric and mechanical, to an SMA wire and demonstrate that this material can mimic the response of the avian humerotriceps, a skeletal muscle that acts in the dynamic control of wing shapes. We next numerically evaluate the feasibility of using SMA springs as artificial leg muscles for a bipedal walking robot. Altering the phase offset between mechanical and electrical stimuli was sufficient for both synthetic and natural muscle to shift between actuation, braking and spring-like behaviour.

scholarly journals Fast Sheath-driven Electrothermal Artificial Muscles with High Power Densities

2021 ◽  
Author(s):  
Xinghao Hu ◽  
Jingjing Jia ◽  
Yingming Wang ◽  
Xintian Tang ◽  
Shaoli Fang ◽  
...  
Keyword(s):  
Direct Contact ◽  
High Performance ◽  
Large Diameter ◽  
Average Power ◽  
Artificial Muscles ◽  
Slow Cooling ◽  
Prior Art ◽  
Performance Results ◽  
Power Densities ◽  
Sheath Material

Abstract Electrothermal carbon nanotube (CNT) yarn muscles can provide large strokes during heating-cooling cycles. However, the slow cooling rate of thermal muscles limit their applications, since large diameter prior-art thermal muscles cannot be rapidly cycled. We here report an ultrafast thermally powered sheath-driven yarn muscle that uses a hybrid CNT sheath and an inexpensive polymer core. Our coiled muscle contracts 14.3% at 1 Hz and 7.3% at 8 Hz in air when powered by a square-wave electrical voltage input. The 70-mm-diameter actuated muscle cools in air to 16℃ from 150℃ within 0.5 s, compared with 6 s for a 65-mm-diameter sheath-run muscle that uses an electrothermally heated CNT core and 9 s for a 78-mm-diameter muscle that uses the sheath material for the entire muscle. An average power density of 12 kW/kg was obtained for a sheath-driven muscle, which is 42 times that for human skeletal muscle. This high performance results since the heating that drives fast actuation cycles is largely restricted to the muscle sheath, and this sheath is in direct contact with ambient temperature air.

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.

Sign in / Sign up

Export Citation Format

Share Document