Numerical modelling and experimental validation of a McKibben pneumatic muscle actuator (original) (raw)
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Numerical Modelling and Experimental Validation of a Pneumatic Muscle Actuator
Proceedings of the JFPS International Symposium on Fluid Power, 1999
In this paper a modification of the McKibben pneumatic muscle, following the idea of a research group from the University of Warsaw, is implemented and manufactured. The muscle consists of asilicon bladder that is attached at either end to fittings; it has the shape of a tube. Inside the silicon bladder longitudinal high resistance cables are inserted with some circular rings. When the internal bladder is pressurised the actuator shorten. A Finite Element Modelling, using the Mooney-Rivlin formulation with two coefficients for the rubber and with truss elements for the longitudinal cables of the muscle, is used to forecast its behaviour. A prototype has been manufactured. A test bed has been developed to measure the mechanical characteristics of the actuator. The results of the comparison between the model and the prototype are presented and discussed. The F.E. model optimised in this way can be used to design every shape of this kind of pneumatic muscle actuator and to define simplified design procedure.
Actuators, 2017
To clarify the advantages of using soft robots in all aspects of life, the effective behaviour of the pneumatic muscle actuator (PMA) must be known. In this work, the performances of the PMA are explained and modelled in three formulas. The first formula describes the pulling force of the actuator based on the structure parameters; furthermore, the formula presented is the generalised contraction force for wholly PMAs. The second important model is the length formula, which is modified to our previous work to fit different actuator structures. Based on these two models, the stiffness of the actuator is formulated to illustrate its variability at different air pressure amounts. In addition, these formulas will make the selection of proper actuators for any robot arm structure easier using the knowledge gained from their performance. On the other hand, the desired behaviour of this type of actuator will be predefined and controlled.
Journal of Robotics
Modelling the behaviour of Pneumatic Artificial Muscle (PAM) has proven difficult due to its highly complicated structure, nonlinear nature of rubbery material, and air compressibility. To overcome these limitations, a FEM (Finite Element Method) model using Abaqus and CATIA is derived for the quantitative analysis on the impact of different factors on the pulling force of PAM. In the Abaqus a two parameter Mooney–Rivlin model is utilized to consider the hyper-elastic nature of flexible material. Then both Abaqus and CATIA are used in the parametric design of a 3-Dimensional model of PAM. Furthermore, the FEM model is employed to predict the static force exerted by PAM and the results show that the model is promising. The FEM model produces closer results to the test data for the typical PAM. Nonlinear behaviour of PAM is found to be obvious with an increase in both the contraction and the air pressure, different from the linear curves obtained by the fundamental geometrical model. ...
Simulation and Analysis of Pneumatic Artificial Muscle
Pneumatic muscle driven by compressed air is becoming more and more important in modern industrial systems. Such muscles are used in robotic applications. The aim of this work centers on the dynamic simulation of air muscle. Pneumatic air muscle is made mainly of an inflatable and flexible membrane. In this project, we made a model of Pneumatic air muscle using inner silicon tube and braided sleeve made up of Polyethane terephthalate (PET). Sleeve supports the tube as the tube alone can't bear the higher loads and without sleeve it would rupture due to high pressure. We did the dynamic simulation of PAM in ANSYS and we observed the analytical results and according to the obtained results, we decided the dimension and pressure limits. We also did the practical experiment of the manufactured muscle with a controlled air pressure and observed the actual results. In the end, we compared the analytical and actual results of the same.
Development of a Straight Fibers Pneumatic Muscle
International Journal of Automation Technology, 2018
This paper presents the development and implementation of a pneumatic muscle actuator based on an idea proposed by a research group at the University of Warsaw. The muscle comprises a silicone rubber tube with plugs at the ends. The tube wall contains high-rigidity wires arranged parallel to the tube axis. Circular rings are present on the exterior of the tube. When air is introduced into the tube, the actuator becomes bulky and contracts. In order to establish a prediction model of muscle behavior, a finite element model was developed, and in this model, the Mooney-Rivlin formulation was implemented with two coefficients for rubber simulation and truss elements for the wires. Several prototypes were developed, and a test bench for the experimental characterization of muscle performance was set up. The results of comparison between prototype behavior and model prediction are presented. The finite element model can be used to design the actuator with different dimensions; hence, it w...
Analysis and Modeling of Tap-Water/Pneumatic Drive McKibben Type Artificial Muscles
International Journal of Mechanical Engineering and Robotics Research, 2017
This study is concerned with comparative analyses and modeling of both tap-water and pneumatic drive McKibben type artificial muscles. McKibben type pneumatic artificial muscles have been widely used in various fields, especially medical and welfare fields. On the other hand, tap-water drive muscles are proposed because conventional pneumatic muscles require a compressor to generate compressed air. In this paper, to examine some static and dynamic characteristics of them such as contraction ratio, time-delay, and time constant, an experimental setup, which can be used to control the tapwater and pneumatic drive muscles, is constructed and then the differences on the characteristics of them are examined by comparative analyses. It is useful to investigate the characteristics in order to figure out the availability and suitable applications of them. In addition, difference on modeling are investigated by using system identification technique. As a result, the identified model of the pneumatic drive muscle is more complex than the model of the tapwater drive muscle because of nonlinearity due to compressibility of working medium.
Static Modeling of Braided Pneumatic Muscle Actuator: An Amended Force Model
2021
The present study reports an amended static force model for a pneumatic muscle actuator (PMA) used in different aerodynamic and fluid power system applications. The PMA is a fluid actuator, made of a polymeric bladder enclosed in a braided mesh sleeve. A physics-based static model is developed to predict the deformation response of the actuator for different applied pressure. The significant losses, like braid-to-braid friction, non-cylindrical ends, and bladder hyperelasticity effect, have been considered to enhance the model’s practical feasibility. However, a combined effect of all these losses in the PMA was ignored in the literature. The findings of the derived model agree well with existing experimental results.
Numerical modelling and experimental validation of pneumatic muscle actuator
1999
For the joint strength prediction of bonded joints, Fracture Mechanics-based techniques are often used. In this context, the tensile and shear toughness of the adhesives are two of the most important parameters to predict the joint behavior. The Finite Element Method has been used for strength prediction in the last decades. Cohesive zone modelling coupled to a FEM analysis is generally accepted as an accurate method. More recently, the Extended Finite Element Method (XFEM) has emerged. This work aims to validate the XFEM to predict the behavior of stepped-lap joints bonded with the adhesive Araldite ® 2015. Peel and shear stresses in the bondline were evaluated, which allows an analysis of the behavior of the adhesive under different geometrical conditions. For the XFEM strength prediction, different damage initiation criteria were used based on either stresses or strains. The damage law shape was also evaluated, namely the linear and exponential damage propagation laws. The XFEM was found to be adequate to predict the joint strength using the Quadratic Stress and Maximum Stress damage initiation criteria.
Experimental Characterization and Static Modeling of McKibben Actuators
Journal of Mechanical Design, 2009
McKibben actuators are pneumatic actuators with very high force to weight ratios. Their ability to match the behavior of biological muscles better than any other actuators has motivated much research into the characterization and modeling of these actuators. The purpose of this paper is to experimentally characterize the behavior of McKibben artificial muscles with basic geometric parameters, and present a model that is able to predict the static behavior accurately in terms of blocked force and free displacement. A series of experiments aimed at understanding the static behavior of the actuators was conducted. The results for three different lengths (4 in., 6 in., and 8 in.), three diameters (1/8 in., 1/4 in., and 3/8 in.), and one wall thickness (1/16 in.) at pressures ranging from 10 psi to 60 psi illustrate the key design trends seen in McKibben actuator geometry. While existing models predict this static behavior, there are varying degrees of accuarcy, which motivates the prese...
Advanced Robotics, 2012
This paper introduces the third generation of Pleated Pneumatic Artificial Muscles (PPAM), which has been developed to simplify the production over the first and second prototype. This type of artificial muscle was developed to overcome dry friction and material deformation, which is present in the widely used McKibben muscle. The essence of the PPAM is its pleated membrane structure which enables the muscle to work at low pressures and at large contractions. In order to validate the new PPAM generation, it has been compared with the mathematical model and the previous generation. The new production process and the use of new materials introduce improvements such as 55% reduction in the actuator's weight, a higher reliability, a 75% reduction in the production time and PPAMs can now be produced in all sizes from 4 to 50 cm. This opens the possibility to commercialize this type of muscles so others can implement it. Furthermore, a comparison with experiments between PPAM and Festo McKibben muscles is discussed. Small PPAMs present similar force ranges and larger contractions than commercially available McKibben-like muscles. The use of series arrangements of PPAMs allows for large strokes and relatively small diameters at the same time and, since PPAM 3.0 is much more lightweight than the commong McKibben models made by Festo, it presents better force-to-mass and energy to mass ratios than Festo models.