A Method of Designing and Fabricating Mckibben Muscles Driven by 7 MPa Hydraulics

2012 ◽  
Vol 6 (4) ◽  
pp. 482-487 ◽  
Author(s):  
Kazuhiro Iwata ◽  
◽  
Koichi Suzumori ◽  
Shuichi Wakimoto ◽  
Keyword(s):  
High Power ◽  
Water Pressure ◽  
Fem Analysis ◽  
Artificial Muscle ◽  
High Strength ◽  
Maximum Pressure ◽  
Artificial Muscles ◽  
Rubber Tube ◽  
Robot Hands ◽  
Pbo Fiber

Research has recently been increasing on light weight and high-power robot hands that use artificial muscles. By applying ultra high strength PBO fiber sleeves to McKibben artificial muscles, new hydraulic artificial muscles have been developed in our laboratory. In this research, to apply this technology to a high-power robot easily, we have developed new, thin, hydraulic artificial muscles. While the hydraulic artificial muscles reported in our previous paper were driven by a maximum water pressure of 4 MPa, the newly developed thin muscles are driven by water with a maximum pressure of 7 MPa, resulting in very high force capability. This paper details the materials and structure of the new artificial muscles and reports the results of experiments on them. The muscles developed in this work are based on a sleeve and rubber tube design. The movements of the muscles depend on the angle of the knit of sleeve: an angle of less than 54.5 deg produces contraction while an angle of more than 54.5 deg produces extension. Based on this idea, we optimize, using FEM analysis, the angle of knit of the sleeve of each muscle. As a result, a high powered artificial muscle 21 mm in diameter which generates 8 kN of contraction force has been successfully developed.

A modified physical model of high-strength water hydraulic artificial muscles considering the effects of geometry and material properties

2021 ◽  
pp. 095440622199907
Author(s):  
Zengmeng Zhang ◽  
Jinkai Che ◽  
Peipei Liu ◽  
Yunrui Jia ◽  
Yongjun Gong
Keyword(s):  
Physical Model ◽  
Relative Error ◽  
Wall Thickness ◽  
Material Properties ◽  
High Strength ◽  
Artificial Muscles ◽  
Operating Pressure ◽  
Rubber Tube ◽  
Contraction Ratio ◽  
Water Hydraulic

Compared with pneumatic artificial muscles (PAMs), water hydraulic artificial muscles (WHAMs) have the advantages of high force/weight ratio, high stiffness, rapid response speed, large operating pressure range, low working noise, etc. Although the physical models of PAMs have been widely studied, the model of WHAMs still need to be researched for the different structure parameters and work conditions between PAMs and WHAMs. Therefore, the geometry and the material properties need to be considered in models, including the wall thickness of rubber tube, the geometry of ends, the elastic force of rubber tube, the elongation of fibers, and the friction among fiber strands. WHAMs with different wall thickness and fiber materials were manufactured, and static characteristic experiments were performed when the actuator is static and fixed on both ends, which reflects the relationship between contraction force and pressure under the different contraction ratio. The deviations between theoretical values and experimental results were analyzed to investigate the effect of each physical factor on the modified physical model accuracy at different operating pressures. The results show the relative error of the modified physical model was 7.1% and the relative error of the ideal model was 17.4%. When contraction ratio is below 10% and operating pressure is 4 MPa, the wall thickness of rubber tube was the strongest factor on the accuracy of modified model. When the WHAM contraction ratio from 3% to 20%, the relative error between the modified physical model and the experimental data was within ±10%. Considering the various physical factors, the accuracy of the modified physical model of WHAM is improved, which lays a foundation of non-linear control of the high-strength, tightly fiber-braided and thick-walled WHAMs.

scholarly journals Improvement of Elastomer Elongation and Output for Dielectric Elastomers

2021 ◽  
Author(s):  
Seiki Chiba ◽  
Mikio Waki ◽  
Shijie Zhu ◽  
Tonghuan Qu ◽  
Kazuhiro Ohyama
Keyword(s):  
Power Systems ◽  
Research And Development ◽  
Electrostatic Force ◽  
Artificial Muscle ◽  
High Strength ◽  
Carbon Foam ◽  
Artificial Muscles ◽  
Market Demand ◽  
The World ◽  
Swcnts And Mwcnts

The need for light, high-strength, and artificial muscles is growing rapidly. A well-known type of artificial muscle meeting these requirements is the dielectric elastic (DE) type, which uses electrostatic force between electrodes. In hopes of utilizing, it practically for a variety of purposes, research and development is rapidly progressing all over the world as a technology for practical use. Much of the market demand is dominated by more output-focused applications such as DE power suits, DE motors, DE muscles for robots, and larger DE power systems. To meet these demands, the elasticity of the elastomer is very important. In this paper, we discussed what the important factors are for SS curves, viscoelasticity tests, etc. of the dielectric elastomer materials. Recent attempts have been also made to use new carbon foam materials such as SWCNTs and MWCNTs as electrodes for DEs. These electrodes bring the elastomers to a higher level of performance.

Mechanical Properties Analysis on Elongation Type of Pneumatic Artificial Muscles

2011 ◽  
Vol 110-116 ◽  
pp. 1313-1320
Author(s):  
De Xu Geng ◽  
Ji Zhao ◽  
Lei Zhang ◽  
Yun Wei Zhao
Keyword(s):  
Mechanical Properties ◽  
Artificial Muscle ◽  
Bending Stiffness ◽  
Air Pressure ◽  
Artificial Muscles ◽  
Rubber Tube ◽  
Accuracy Control ◽  
Axial Deformation ◽  
Bending Angle ◽  
Flexible Joint

This paper developed a novel elongation type of Pneumatic Artificial Muscle (PAM), which is mainly composed of the expandable internal rubber tube surrounded by the external cylindrical helical spring and the two ends are closed. The PAM is not only the actuator of the flexible joint but also the core components to make up of the flexible joint. Therefore, the mechanical properties of the PAM directly influence the performance of the flexible joint. A mathematical model on the axial deformation and bending stiffness of elongation type of PAM was built applying theoretical analysis and experimental research methods. The results show that the axial deformation of PAM and the air pressure supplying to the PAM are nonlinearly related due to the generic nonlinear of deformation of the rubber tube; the bending angle of the PAM is proportional to moment; Similarly, the bending angle of the PAM is also proportional to its length. Furthermore, it indicates that the air pressure indirectly affects the bending stiffness of PAM as the air pressure directly influences the elongation of PAM. Finally, this paper provides a powerful framework for the dynamic analysis and motion accuracy control of the flexible joint or the robot which is composed by the artificial muscles.

scholarly journals Development of Soft Pneumatic Actuators Using High-Strain Elastic Materials with Stress Anisotropy of Short Fibers

Proceedings ◽  
2020 ◽  
Vol 64 (1) ◽  
pp. 41
Author(s):  
Akihiro Kojima ◽  
Manabu Okui ◽  
Taro Nakamura
Keyword(s):  
Fiber Type ◽  
Artificial Muscle ◽  
Axial Direction ◽  
Short Fiber ◽  
Working Fluid ◽  
Artificial Muscles ◽  
Rubber Tube ◽  
Fiber Reinforced ◽  
Soft Robots ◽  
Soft Actuators

In recent years, soft robots, such as those with high human affinity and those that excellently imitate the movements of natural creatures, have gained considerable attention. In soft robots, structurally flexible soft actuators need to be used, not conventional motors or hydraulic/pneumatic cylinders. Various types of soft actuators have been developed depending on the driving principle. A pneumatic rubber artificial muscle is a kind of soft actuator that acquires power through injection of a working fluid, such as air, into an elastic structure, such as rubber. In this study, the authors developed an actuator, namely, the straight-fiber-type artificial muscle, which exhibits excellent contraction characteristics. This artificial muscle consists of a rubber tube that contains reinforcing fibers arranged in the axial direction. When air pressure is applied to the rubber tube, the artificial muscle expands only in the radial direction and contracts in the axial direction due to the restraining effect of the reinforcing fiber. While this artificial muscle exhibits excellent contraction properties, it has some drawbacks. One is the difficulty in enclosing the reinforced fibers that have accumulated in the rubber tube, making this artificial muscle difficult to manufacture. In this study, we investigated short-fiber-reinforced artificial muscles that can be easily manufactured. First, a short-fiber-reinforced rubber was prepared, and anisotropy was evaluated via a tensile test. Then, the short-fiber-reinforced artificial muscles were prepared, and their contractions rates were evaluated. The results confirmed that a short-fiber-reinforced rubber can be useful for the manufacture of artificial muscles.

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.

FEM Analysis and Experimental Study for Bond Strength of High-Strength Coating by Wedged Load Test Method

2010 ◽  
Vol 152-153 ◽  
pp. 1058-1061
Author(s):  
Zhou Wei ◽  
Xiao Xia Zhang
Keyword(s):  
Bond Strength ◽  
Adhesion Strength ◽  
Fem Analysis ◽  
High Strength ◽  
Pressure Head ◽  
Optical Microscope ◽  
Complex Stress ◽  
Complex Stress State ◽  
Load Test ◽  
Test Method

A wedged load test method is used to evaluate the adhesion strength of high-strength coatings, which have been processed with various sintering parameters. In this test, for stress concentration at cut tip, cracks are always induced and expanded rapidly cross the interface between coating and substrate. Macro-fracture and SEM image of coating interface of high-strength coating are characterized using optical microscope and scanning electron microscopy (SEM), respectively. In order to evaluate the bonding properties between coating and substrate effectively, corresponding finite element (FE) analysis has been conducted to evaluate the adhesion strength of high-strength coating. And stress distributions cross the interface of high-strength coating are obtained. The stress analysis can help to evaluate the bond strength of high-strength coating. Because of small specimen and contact relationship between wedged pressure head and wedged cuts, complex stress state is affected by many factors resulting from interface, and also by the thickness of coating.

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,...

An Enhanced Hybrid Springback Compensation Approach: Springback Path – Displacement Adjustment Method For Complex Shaped Products of Sheet Metal Forming

2021 ◽  
Author(s):  
Zhihui Gong ◽  
Mandeep Singh ◽  
Bohao Fang ◽  
Dongbin Wei
Keyword(s):  
Sheet Metal ◽  
Automobile Industry ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
High Strength Steels ◽  
Fem Analysis ◽  
High Strength ◽  
Design Stage ◽  
Springback Compensation ◽  
Compensation Approach

Abstract Springback compensation is critical in sheet metal forming. Advanced techniques have been adopted in the design stage of various sheet metal forming processes, e.g. stamping, some of which are for complex shaped products. However, the currently available numerical approaches are not always sufficiently accurate and reliable. To improve the accuracy of springback compensation, an enhanced hybrid springback compensation method named Springback Path – Displacement Adjustment (SP-DA) method has been developed in this study based on the well-known conventional displacement adjustment (DA) method. Its effectiveness is demonstrated using FEM analysis of low, medium and high strength steels adopted in automobile industry, in which a symmetrical model owning geometry complexity similar to an auto body panel was established. The results show this new enhanced SP-DA method is able to significantly improve the accuracy of springback compensation comparing to conventional displacement adjustment technique.

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.

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