Development of a new system for reducing the temperature increase during the positioning of spoilers using pneumatic artificial muscle (PAM)

2020 ◽  
Vol 92 (8) ◽  
pp. 1257-1261
Author(s):  
Mustafa Soylak ◽  
Mustafa Bakır

Purpose The usage of pneumatic artificial muscles (PAMs) is becoming increasingly widespread across a variety of industries because of its advantages such as its lightness and its ability to generate a huge amount of force using the fewest components. The purpose of this paper is to develop a piece of hardware to minimize and equally distribute the thermal changes on the surface of a PAM when positioning using PAMs. A classic PAM and a PAM that contains the hardware suggested for tasks, such as the positioning of spoilers decelerating control surfaces for aircrafts, were compared experimentally. Design/methodology/approach Rapid thermal changes were detected in the classic PAM, especially at the tip of the PAM. These thermal changes decrease the positioning sensitivity and reliability, thus shortening life span of the PAMs. A component was developed that could create a circulation of air around the tip of the PAM, preventing the temperature increase caused by still air. It is installed inside the PAM and makes it possible to control the pressurized air volume in crucial areas. Shaped as a perforated metal pipe, the component was embedded inside the PAM and effects of this component were investigated. Findings The experiment results have shown that, thanks to the system that was developed, cool air that comes from outside is able to reach the tip of the PAM every time, thus keeping regional temperature increase to a minimum. The temperature increase in the pressurized air inlet was minimized by creating a circulation of air in the area. Originality/value With this study, the distribution of heat in different areas on PAM was homogenized at a low cost using the component that was developed.

2019 ◽  
Vol 10 (1) ◽  
pp. 43 ◽  
Author(s):  
Tsung-Chin Tsai ◽  
Mao-Hsiung Chiang

This study determines the practicality and feasibility of the application of pneumatic artificial muscles (PAMs) in a pneumatic therapy robotic system. The novel mechanism consists of a single actuated pneumatic artificial muscle (single-PAM) robotic lower limb that is driven by only one PAM combined with a torsion spring. Unlike most of previous studies, which used dual-actuated pneumatic artificial muscles (dual-PAMs) to drive joints, this design aims to develop a novel single-PAM for a one degree-of-freedom (1-DOF) robotic lower-limb system with the advantage of a mechanism for developing a multi-axial therapy robotic system. The lower limb robotic assisting system uses the stretching/contraction characteristics of a single-PAM and the torsion spring designed by the mechanism to realize joint position control. The joint is driven by a single-PAM controlled by a proportional pressure valve, a designed 1-DOF lower-limb robotic system, and an experimental prototype system similar to human lower limbs are established. However, the non-linear behavior, high hysteresis, low damping and time-variant characteristics for a PAM with a torsion spring still limits its controllability. In order to control the system, a fuzzy sliding mode controller (FSMC) is used to control the path tracking for the PAM for the first time. This control method prevents approximation errors, disturbances, un-modeled dynamics and ensures positioning performance for the whole system. Consequently, from the various experimental results, the control response designed by the joint torsion spring mechanism can also obtain the control response like the design of the double-PAMs mechanism, which proves that the innovative single-PAM with torsion spring mechanism design in this study can reduce the size of the overall aid mechanism and reduce the manufacturing cost, can also improve the portability and convenience required for the wearable accessory, and is more suitable for the portable rehabilitation aid system architecture.


Author(s):  
Benjamin K. S. Woods ◽  
Shane M. Boyer ◽  
Erica G. Hocking ◽  
Norman M. Wereley ◽  
Curt S. Kothera

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.


2020 ◽  
Vol 5 (41) ◽  
pp. eaaz4239 ◽  
Author(s):  
Seyed M. Mirvakili ◽  
Douglas Sim ◽  
Ian W. Hunter ◽  
Robert Langer

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.


2009 ◽  
Vol 3 (6) ◽  
pp. 731-740 ◽  
Author(s):  
Shinji Kuriyama ◽  
◽  
Ming Ding ◽  
Yuichi Kurita ◽  
Jun Ueda ◽  
...  

The demand for flexible, lightweight McKibben pneumatic artificial muscles (McKibben actuators) has been increasing for power assistance equipment used for assisting and rehabilitating the elderly. To accurately control this equipment, the length of the actuator should be measured. However, the equipment becomes heavier and less flexible when a rigid sensor, such as a potentiometer or an encoder, is used. The sensor should be flexible in order to take advantage of the favorable properties of the McKibben actuator. The aim of this study is to measure the length of the actuator without loss of its advantages. We propose a method of estimating the length from the circumferential displacement, which can be measured by a sensor made of electroconductive, flexible rubber. Higher accuracy is obtained by measuring the circumferential displacement than by measuring the axial displacement using this sensor. The sensor’s flexibility enables us to accurately control the actuator without any loss of flexibility or increase in weight. Furthermore, the sensor does not require the attachment of any rigid fixtures. The accuracy of the estimate is successfully evaluated and the usefulness of the proposed method is verified through its application to a multi-link arm driven by the McKibben actuator.


2020 ◽  
Vol 32 (5) ◽  
pp. 885-893
Author(s):  
Naoki Saito ◽  
Daisuke Furukawa ◽  
Toshiyuki Satoh ◽  
Norihiko Saga ◽  
◽  
...  

This paper describes a semi-crouching assistive device using pneumatic artificial muscles. The goal of this device is to reduce the load on the lower back when performing work in the semi-crouching position. The load on the lower back is reduced by decreasing the compressive pressure on the lumbar disk of the lower back. This compressive pressure increases as the contraction force of the erector spine increases. Therefore, it is important to reduce the muscle activity of the erector spine. Based on the analytical result of a worker’s position model, the proposed device adopts a scheme to push the chest of the user as an appropriate assistive method. Additionally, the analytical result shows that a reduction in weight of the device is also important for decreasing the load on the lower back. Based on these results, we prototyped a lightweight semi-crouching assistive device that can generate sufficient assistive force via a pneumatic artificial muscle, which has high power to weight ratio. This device was experimentally evaluated via electromyogram of the erector spine when the user maintains a semi-crouching position. The experimental results confirmed the usefulness of this device.


2013 ◽  
Vol 308 ◽  
pp. 39-44 ◽  
Author(s):  
Mária Tóthová ◽  
Ján Piteľ ◽  
Jana Boržíková

The paper describes operating modes of the PAM based actuator consisting of two pneumatic artificial muscles (PAMs) in antagonistic connection. The artificial muscles are acting against themselves and resultant position of the actuator is given by equilibrium of their forces according to different pressures in muscles. The main requirement for operation of such pneumatic actuator is uniform movement and accurate arm position control according to input desired variable. There are described in paper operation characteristics of the pneumatic artificial muscle in variable pressure and then operation characteristics of the pneumatic artificial muscle actuator consisting of two muscles in antagonistic connection.


2019 ◽  
Vol 256 ◽  
pp. 01005
Author(s):  
Feng Ning ◽  
Yingli Chang ◽  
Jingze Wang

Pneumatic artificial muscles (PAMs) can offer excellent force-to-weight ratios and act as shape-changing actuator under injecting the actuation fluid into their bladders. PAMs could be easily utilized for morphing structures due to their millimeter-scale diameter. The pressurized PAM can serve not only as artificial muscle actuator which obtains contraction deformation capability but also as a spring system with variable stiffness. In this study, the stiffness behaviors of pressurized PAMs and a variable stiffness structure are investigated. By taking advantage of the designed PAMs which was conducted by the non- linear quasi-static model, significant changes in the spring stiffness can be achieved by air pressure control. A case study is presented to explore the potential behavior of a structure with circular permutation PAMs. The structure used in this case consists of sixteen PAMs with circular homogeneous distribution and a circular supporter with sixteen slide way runners. The stiffness of presented structure can vary flexibly in wide range through controlling the air pressure levels and slide deformation respectively.


Author(s):  
Chen Su ◽  
Ao Chai ◽  
Xikai Tu ◽  
Hongyu Zhou ◽  
Haiqiang Wang ◽  
...  

Nerve injury can cause lower limb paralysis and gait disorder. Currently lower limb rehabilitation exoskeleton robots used in the hospitals need more power to correct abnormal motor patterns of stroke patients’ legs. These gait rehabilitation robots are powered by cumbersome and bulky electric motors, which provides a poor user experience. A newly developed gait rehabilitation exoskeleton robot actuated by low-cost and lightweight pneumatic artificial muscles (PAMs) is presented in this research. A model-free proxy-based sliding mode control (PSMC) strategy and a model-based chattering mitigation robust variable control (CRVC) strategy were developed and first applied in rehabilitation trainings, respectively. As the dynamic response of PAM due to the compressed air is low, an innovative intention identification control strategy was taken in active trainings by the use of the subject’s intention indirectly through the estimation of the interaction force between the subject’s leg and the exoskeleton. The proposed intention identification strategy was verified by treadmill-based gait training experiments.


Author(s):  
Michael F. Gentry ◽  
Norman M. Wereley

Pneumatic artificial muscles (PAMs) provide numerous advantages for use as actuators in a wide variety of mechanical systems. Our study focused on determining the effects of braid angle on the performance of PAMs. This paper discusses how we constructed a set of PAMs with varying braid angle, predicted their performance using analytical models, gathered empirical data characterizing the PAMs, and compared the analytical predictions with the experimental results. We constructed six PAMs of different braid angles between 38° and 73°. To predict PAM performance, we used an analysis based on the force equilibrium equations for a pressurized actuator. We first quantified the performance limits of each actuator in a series of static characterization tests. Then we subjected each PAM to cyclical displacement testing. Finally, a series of cyclical tests were performed with a pre-strain applied to the PAMs, to better approximate their typical use. Our results showed variation of braid angle causes significant differences in performance among the six PAMs tested; PAMs with larger braid angle generated higher blocked force and exhibited greater contraction. The empirical data matched the model predictions based on our estimates for the braid angle of a given PAM.


2009 ◽  
Vol 15 ◽  
pp. 49-54
Author(s):  
S. Díaz-Zagal ◽  
C. Gutiérrez-Estrada ◽  
E. Rendón-Lara ◽  
I. Abundez-Barrera ◽  
J.H. Pacheco-Sánchez

Actually, the pneumatic artificial muscles of McKibben type [1] show a great functional similarity with the skeletal muscle. A detailed analysis of the system has been performed to better characterize this similarity with the analogous dynamic behavior of the organic system. Such analysis has shown that the McKibben-type artificial muscle can be adapted to the Hill fundamental model [2]. Research regarding pneumatic artificial muscle with application to robotics has recently focused on mini-actuators for miniaturized robotics systems. This is specially true in the area of medical robotics, but an extension of miniactuator technology to other applications may be feasible, such as the development of artificial fine-motion limbs (hands and/or fingers). The present work details the artificial muscle miniaturization process developed in the LESIA laboratory, their behavior, their position and force control characteristics, as well as the possible applications of this technology to medical robotics.


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