Numerical modelling and experimental validation of a McKibben pneumatic muscle actuator

Abstract

The McKibben muscle belongs to the type of muscles known as braided muscles. It is made of an inner hyper-elastic tube, surrounded by a braided shell made of inextensible threads; both ends provide mechanical and pneumatic seal. A finite element model of a McKibben pneumatic muscle was built and experimentally validated. The model is based on characteristic parameters of McKibben muscles. It takes into account the non-linearity of the constitutive material of the inner tube. It does not simulate backslashes between the tube and the shell at rest condition, but it models threads and rubber that are always connected. However, it does not consider friction among threads. In order to build and to validate the proposed numerical model, an experimental prototype of the muscle was designed and built. Both isotonic and isometric tests were carried out. Same tests were simulated in the finite element environment. The model validation was performed by comparison between experimental and numerical results.

Additive Manufacturing Applications on Flexible Actuators for Active Orthoses and Medical Devices

“…The former have been the subject of research activities and find space in some industrial applications, as they are available in the automation components market; the latter are not present in the market but are often designed ad hoc and integrated into commonly used devices such as blood pressure measurement systems and other medical devices, such as car seats and massage chairs. Two types of pneumatic muscles have been developed [11, 12]: straight fibres and braided, also known as McKibben muscle. The straight fibres pneumatic muscle (Figure 5(a)) is made of a silicone cylindrical chamber in the wall in which a cage consists of 40 Kevlar threads, arranged longitudinally and held in position by two end rings, in which one is buried inside the silicone and the other is connected to the head that contains the air supply/discharge pipe.…”

“…In these models, the braided shell is analysed with average parameters available in the literature. The finite element model of the braided pneumatic muscle developed by the authors has been experimentally validated [11]. The model developed is nonlinear and based on real muscle parameters.…”

Modelamento Fenomenológico de um Músculo de Mckibben de Baixo Custo

“…Dentre outras metodologias utilizadas para modelar o comportamento do músculo podem ser citadas a abordagem termofluidodinâmica (Paynter e Juarez, 1999), mecânica do contínuo (Gasser e Holzapfel, 2002;Klute e Hannaford, 2000), mecânica Newtoniana (Schulte e Pearson, 1961;Caldwell et al, 2000Caldwell et al, e 2007 e o princípio do trabalho virtual ou PTV (Caldwell, 1993;Chou e Hannaford, 1996;Caldwell et al, 2005;Davis e Caldwell, 2006;Tondu et al, 2012;Zhang e Philen, 2012;Antonelli et al, 2017;Chapman e Bryant, 2018). O PTV é a metodologia mais empregada, pois, parte do princípio da conservação da energia, em que a energia de entrada, fornecida pela pressão interna, é convertida em trabalho.…”

The hysteresis modeling of pneumatic artificial muscles using least squares support vector machine approach

“…On the contrary, the soft robots can realize continuous deformation and large-scale motion profiting from soft or flexible materials, which can remedy for these shortcomings of rigid robots. As an important subfield of software robots, the pneumatic artificial muscle (PAM) is composed of a flexible cylindrical rubber surrounded by a braided mesh shell (Antonelli et al, 2017). This unique structure makes it possess the advantages including high power/ weight ratio, low cost, compactness, and noteworthily similar pliability as organic muscles (Tondu, 2012).…”