scholarly journals Experimental Research on the Hysteretic Behaviour of Pressurized Artificial Muscles Made from Elastomers with Aramid Fibre Insertions

Actuators ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 83
Author(s):  
Ovidiu Filip ◽  
Andrea Deaconescu ◽  
Tudor Deaconescu
Keyword(s):  
Experimental Research ◽  
High Performance ◽  
Hysteresis Loops ◽  
Artificial Muscles ◽  
Degree Polynomial ◽  
Pneumatic Muscle ◽  
Positioning Systems ◽  
Hysteretic Behaviour ◽  
Aramid Fibres ◽  
Hysteresis Behaviour

Inherent hysteresis behaviour of pressurized artificial muscles is complicated to understand and handle, calling for experimental research that allows the modelling of this phenomenon. The paper presents the results of the experimental study of the hysteretic behaviour of a small-size pneumatic muscle. The specific hysteresis loops were revealed by isotonic and isometric tests. Starting from hypothesis according to that the tube used for the pneumatic muscle is made entirely of aramid fibres enveloped by an elastomer material that merely ensures their airtightness, the paper presents the hysteresis curves that describe the radial and axial dimensional modifications as well as the variation of the developed forces for different feed pressures. The obtained third-degree polynomial equations underlie the configuration of high-performance positioning systems.

scholarly journals Studies Regarding the Use of Pneumatic Muscles in Precise Positioning Systems

2021 ◽  
Vol 11 (21) ◽  
pp. 9855
Author(s):  
Ioana Mădălina Petre
Keyword(s):  
High Performance ◽  
Position Control ◽  
Pressure Control ◽  
Pneumatic Muscle ◽  
Positioning Systems ◽  
Pneumatic Muscles ◽  
Contraction Ratio ◽  
Input Pressure ◽  
Important Challenge ◽  
The Relationship

The paper presents the methods and results of an experimental study that highlights the behavior of a pneumatic actuator under different pressures and with different loads applied. One important challenge that occurs in the application of pneumatic muscles is the phenomenon of hysteresis, which causes a nonlinear relationship between the input–output values. The aim of this study is to identify the occurrence of hysteresis in the operation of a small pneumatic muscle in different conditions. Thus, different loads are attached to the free end of a pneumatic muscle and different successive pressures are applied in order to examine the hysteresis of the contraction ratio when the muscle is inflated and then deflated. The obtained equations that describe the relationship between the input pressure and the axial contraction are significant for reaching a high-performance position control. In this regard, the article proposes a solution to increase positioning accuracy based on pressure control using a proportional pressure regulator and a programmable logic controller.

About the concept of synthesis of high-performance detection and positioning systems in the areas of elements falling, separated from strategic and space missiles on the trajectories of their flight during tests and regular operation

2018 ◽  
pp. 10-21
Author(s):  
G. G. Vokin
Keyword(s):  
High Performance ◽  
Physical Nature ◽  
Positioning Systems ◽  
Physical Conditions ◽  
Highly Efficient

The article describes the approach and topical issues of synthesis of highly efficient transportable systems for search and determination of coordinates in the areas of elements falling, separated from the missiles, taking into account the dislocation of pre-empted areas of fall and physical conditions in their territories. The principles of these systems are based on the rational integration of traditional and non-traditional information sensors of different physical nature, which record the moments of landing of separated parts of the missiles.

UWB Positioning Systsem Design: Selection of Modulation and Multiple Access Schemes

2007 ◽  
Vol 61 (1) ◽  
pp. 45-62 ◽  
Author(s):  
Hui Yu ◽  
Enrique Aguado ◽  
Gary Brodin ◽  
John Cooper ◽  
David Walsh ◽  
...  
Keyword(s):  
Multiple Access ◽  
High Performance ◽  
Ultra Wideband ◽  
Good Time ◽  
Modulation Scheme ◽  
Positioning System ◽  
Indoor Environments ◽  
Signal Design ◽  
Positioning Systems ◽  
Design Selection

In densely-populated cities or indoor environments, limited visibility to satellites and severe multipath effects significantly affect the accuracy and reliability of satellite-based positioning systems. To meet the needs of “seamless navigation” in these challenging environments an advanced terrestrial positioning system is under development. This system is based upon Ultra-Wideband (UWB) technology, which is a promising candidate for this application due to good time domain resolution and immunity to multipath. This paper presents a detailed analysis of two key aspects of the UWB signal design that will allow it to be used as the basis of such a high performance positioning system: the modulation scheme and the multiple access technique. These two aspects are evaluated in terms of spectral efficiency and synchronisation performance over multipath channels. Thus this paper identifies optimal modulation and multiple access techniques for a long range, high performance terrestrial positioning system using UWB.

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.

Experimental Research Regarding Rehabilitation Equipment Behavior on a Recovery Program

2014 ◽  
Vol 555 ◽  
pp. 689-694
Author(s):  
Ioana Mădălina Petre
Keyword(s):  
Experimental Research ◽  
Pneumatic Muscle ◽  
Human Knee ◽  
Human Foot ◽  
Experimental Behavior ◽  
High Incidence ◽  
Recovery Program ◽  
Experimental Researches

The aim of the article is to analyze the experimental behavior of a rehabilitation equipment during a recovery program. It is known the high incidence of the human knee/ankle/hip dysfunctions. So, it had been conceived a pneumatic muscle actuated rehabilitation equipment, for rehabilitation of those types affections. It is presented the components and the experimental researches made considering that on the equipment is a 20 kilos load (considered as a human foot weight). The results of experiments shows the behaviour of the equipment: slider position, speed and acceleration in time – under different commands.

scholarly journals Graphene/silver nanoflower hybrid coating for improved cycle performance of thermally-operated soft actuators

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Chengxu Piao ◽  
Ji Won Suk
Keyword(s):  
High Performance ◽  
Hybrid Coating ◽  
Cycle Performance ◽  
Artificial Muscles ◽  
Pristine Graphene ◽  
Pulsed Current ◽  
Enhanced Heat Transfer ◽  
Graphene Flakes ◽  
Sewing Threads ◽  
Soft Actuators

Abstract Twisted and coiled actuators (TCAs), fabricated by twisting cheap nylon sewing threads, have attracted a great deal of attention for their use as artificial muscles or soft actuators. Since the dynamic behavior of a thermally-operated TCA is governed by its thermal properties, graphene and silver nanoflowers (AgNFs) were spray-coated onto the surface of an actuator to achieve enhanced heat transfer. Addition of AgNFs improves interfacial thermal contacts between graphene flakes, while pristine graphene flakes have extremely high in-plane thermal conductivity. Thus, the synergistic effect of graphene and AgNFs reduced the total cycle time of the TCA by up to 38%. Furthermore, when a pulsed current with a 40% duty cycle was applied to the TCA, the graphene/AgNF-coated TCA exhibited a threefold larger peak-to-peak amplitude of the displacement oscillation of the actuator, as compared to that of the non-coated TCA, which demonstrates that the combination of graphene and AgNFs effectively reduced a cooling time of the TCA. This work shows great potential for a simple coating of graphene and AgNFs to produce high-performance thermally-operated soft actuators.

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