A Novel Geometric Formula for Predicting Contractile Force in McKibben Pneumatic Muscles

2017 ◽  
Vol 11 (3) ◽  
pp. 368-377 ◽  
Author(s):  
Guido Belforte ◽  
◽  
Terenziano Raparelli ◽  
Silvia Alessandra Sirolli
Keyword(s):  
Analytical Formula ◽  
Experimental Models ◽  
Design Tool ◽  
Analytical Models ◽  
Pneumatic Muscle ◽  
Muscle Structure ◽  
Pneumatic Muscles ◽  
Muscle Geometry ◽  
Muscle Types ◽  
Specific Muscle

Several analytical models exist in the literature for predicting the behavior of braided pneumatic muscles (McKibben muscles). Such models take into consideration the various variables and parameters that are related to the muscle geometry, material properties, and the loads applied to the system, and propose various relationships between these variables. Owing to the complexity of the muscle structure, in several cases, instead of a physical model, empirical or experimental models are used, which generally have limited validity for specific muscle types, i.e., they are only valid for a restricted range of operating parameters. This study proposes a new analytical formula based on the geometry of a pneumatic muscle studied in the rest and work phases and a simple experimental method to obtain corrective factors useful to design muscles. A mathematical formula can thus be obtained that allows one to deduce the measurements of interest in the system as a function of the specific parameters and permits one to interpret in qualitative terms the behavior of the muscle at each moment for various values of pressure, contraction, and applied load and to identify any critical situations. This model can therefore be a very useful design tool because it allows one to adapt the muscle geometry based on the required forces and contractions for different applications that are compatible with the muscle structure on which the model is based. This paper also presents a method for evaluating the efficiency of the muscles, useful to better use them in different applications.

Control of a Pneumatic Muscle Actuated Rehabilitation System of the Lower Limb Bearing Joints

2015 ◽  
Vol 809-810 ◽  
pp. 706-711
Author(s):  
Tudor Deaconescu ◽  
Andrea Deaconescu
Keyword(s):  
Human Body ◽  
Lower Limb ◽  
Rehabilitation Medicine ◽  
Medical Systems ◽  
Pneumatic Muscle ◽  
Motion Graphs ◽  
Pneumatic Muscles ◽  
Rehabilitation System

The specific objectives of rehabilitation medicine are maintaining and recovering human body functions, as well as preventing dysfunctionalities by means of kinetic and orthotic techniques and a variety of equipment for support and adaptation. The latter are medical systems facilitating the exercise of muscles at constant or variable speeds according to professional recommendations. The paper presents and discusses the control of rehabilitation equipment designed for the passive mobilisation exercises of joints. The novelty of such equipment resides in its actuation by pneumatic muscles, as well as in its control by means of an SPC 200 controller and WinPISA software. The paper presents a number of examples of rehabilitation programmes and the corresponding motion graphs of the rehabilitation equipment sliding block.

A Numerical Method for the Analysis of the Theoretical Flow in Crescent-Type Internal Gear Machines With Involute Teeth Profile

2019 ◽  
Author(s):  
Dinghao Pan ◽  
Andrea Vacca
Keyword(s):  
Numerical Method ◽  
Fluid Dynamic ◽  
Analytical Formula ◽  
Simulation Models ◽  
Design Tool ◽  
Multiple Control ◽  
Analysis And Design ◽  
Lumped Parameter ◽  
Control Volumes ◽  
Internal Gear

Abstract Lumped parameter approaches for the description of the flow displaced by hydrostatic pumps and motors have proven to be very effective for both analysis and design purposes. However, while these methods are relatively easy to implement for most of the existing design architectures for positive displacement machines, the case of a crescent-type internal gear machine (CIGM) presents clear challenges as it pertains to the definition of lumped control volumes within the machine. This paper proposes an original scheme for defining lumped control volumes within a CIGM with involute teeth profiles, which is suitable for developing fluid dynamic simulation models for CIGMs. The proposed method strictly obeys fundamental rules on continuous volumes required by lumped parameters models. This is achieved by defining not only multiple control volumes for each displacement chamber but also two variable porting volumes to respect the volume conservation. To prove the validity of the proposed numerical method, the paper provides comparisons between the displaced volume found by the proposed lumped parameter approach and the theoretical kinematic flow ripple provided by an analytical formula available from literature. The results show how the method can be used as a design tool for CIGMs, and particularly to further develop lumped parameter simulation models for detailed fluid dynamic analysis of CIGMs.

Design and Control of a Frog-Inspired Swimming Leg Powered by Pneumatic Muscle

2016 ◽  
Author(s):  
Jizhuang Fan ◽  
Gangfeng Liu ◽  
Huan Wang ◽  
Wei Zhang ◽  
Yanhe Zhu
Keyword(s):  
Dynamic Model ◽  
Step Response ◽  
Joint Control ◽  
Pneumatic Muscle ◽  
Experiment Platform ◽  
Pneumatic Muscles ◽  
Ankle Joints ◽  
Self Tuning ◽  
And Control ◽  
Swimming Leg

According to the shortages of previous generation of frog inspired robot, antagonistic joint based frog inspired leg was designed. With the multi-DOFs of hip, knee and ankle, the designed leg was able to perform various frog swimming modes. The dynamic model of antagonistic joint based on advanced pneumatic muscle model was established in MATLAB/Simulink environment. Besides, the servo control strategy of joint angle was studied based on the dynamic model of antagonistic joint. The PID and self-tuning fuzzy control were utilized to control the antagonistic joint. According to different swimming modes, joint trajectories of hip, knee and ankle were created by inverse kinematics based on the frog swimming mechanism. Therefore, the leg was controlled by the separated controls of hip, knee and ankle joints. Feasibility of pneumatic antagonistic joint control was validated via step response experiments with different loads. Finally, the experiment platform was established to carry swimming experiments with the developed frog-inspired swimming leg. The feasibility of antagonistic frog inspired swimming leg driven by pneumatic muscles was validated.

Actuation by Pneumatic Muscles of a Parallel Asymmetric Gripper System

2014 ◽  
Vol 548-549 ◽  
pp. 943-947 ◽  
Author(s):  
Doina Negrea ◽  
Andrea Deaconescu ◽  
Tudor Deaconescu
Keyword(s):  
Pneumatic Muscle ◽  
Natural Systems ◽  
Structural Rigidity ◽  
Pneumatic Muscles ◽  
Gripper Systems

Deployment of pneumatic muscles for the actuation of gripper systems is a solution with numerous benefits, related mostly to the developed force, structural rigidity, compliance and dexterity. The paper discusses a gripper variant with parallel jaws, actuated by a pneumatic muscle. The structure of the mechanism is presented, and the transmission functions of speeds and forces are determined. Due to its construction, the gripper system can be used for precision applications, similar to natural systems.

scholarly journals A Procedure for the Fatigue Life Prediction of Straight Fibers Pneumatic Muscles

Actuators ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 300
Author(s):  
Francesco Durante ◽  
Michele Gabrio Antonelli ◽  
Pierluigi Beomonte Zobel ◽  
Terenziano Raparelli
Keyword(s):  
Fatigue Life ◽  
Silicone Rubber ◽  
Life Prediction ◽  
Experimental Tests ◽  
Fatigue Life Prediction ◽  
Pneumatic Actuators ◽  
Pneumatic Muscle ◽  
Duration Data ◽  
Life Duration ◽  
Pneumatic Muscles

Different from the McKibben pneumatic muscle actuator, the straight fibers one is made of an elastomeric tube closed at the two ends by two heads that ensure a mechanical and pneumatic seal. High stiffness threads are placed longitudinally into the wall of the tube while external rings are placed at some sections of it to limit the radial expansion of the tube. The inner pressure in the tube causes shortening of the actuator. The working mode of the muscle actuator requires a series of critical repeated contractions and extensions that cause it to rupture. The fatigue life duration of a pneumatic muscle is often lower than traditional pneumatic actuators. The paper presents a procedure for the fatigue life prediction of a straight-fibers muscle based on experimental tests directly carried out with the muscles instead of with specimens of the silicone rubber material which the muscle is made of. The proposed procedure was experimentally validated. Although the procedure is based on fatigue life duration data for silicone rubber, it can be extended to all straight-fibers muscles once the fatigue life duration data of any material considered for the muscles is known.

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.

Pneumatic Muscle: Geometry of the Cylindrical Membrane and The Power Characteristic Prognostic

2018 ◽  
pp. 20-34 ◽  
Author(s):  
K. D. Efremova ◽  
V. N. Pilgunov
Keyword(s):  
Elastic Shell ◽  
Experimental Studies ◽  
Original Position ◽  
Internal Cavity ◽  
Internal Diameter ◽  
Numerical Representation ◽  
Pneumatic Muscle ◽  
Pneumatic Muscles ◽  
Shaped Cell ◽  
Force Characteristics

The pneumatic muscle is a pneumatic motor of the single-acting reciprocating motion. It is designed to create apullingforce. Return of the pneumatic muscle to its original position is provided by elastic deformation of its shell. A cylindrical membrane with the hard bottom and the lid provides the basis of the pneumatic muscle.The membrane cord is formed in the process of helically shaped CU-braid of the threads made from the super-hard synthetic fibres (for example, Kevlar). After the cord is filled with an elastomer, a strong, deformable and elastic shell is formed. An excessive pressure applied to the internal cavity of the membrane arises an extension of the tangent diagonal and a simultaneous shortening of the axial diagonal in the diamond-shaped cell, which is formed as a result of braid of cord threads. This results in pneumatic muscle’s retraction up to 25% of its original length, while creating a sufficiently large contraction force, which depends significantly on the contraction value.Using the cord structure of the MAS series pneumatic muscles of the company “FESTO” as an example, we have investigated a diamond-shaped cell deformation of the membrane and have defined a numerical dependence of its internal diameter and the volume of the internal cavity of the pneumatic muscle on the contraction value. This allowed us to develop a mathematical model of an idealized cylindrical membrane whose dynamics does not take into account a deformation force of the elastomer, filling a diamond-shaped cell.The experimental studies of industrial samples of the MAS 10 family of pneumatic muscles, carried out using a specially designed unit, allowed us to obtain their force characteristics. In the numerical representation, these characteristics turned out to be 2.5 ... 3 times less than the force characteristics of the pneumatic muscle with an idealized membrane, thereby allowing us to draw conclusions that the elastomer deformation forces have a significant influence. There is a proposal to take into account the elastomer deformation effect on the force characteristics of the pneumatic muscle by dint of the correction factor available from a comparative estimate of the force characteristics of the idealized membrane and the normalized force characteristics of the pneumatic muscles of the MAS family.The results of the performed studies allow us to predict the force characteristics of pneumatic muscles at the stage of their design and in-service.

Analytical Simulation of Annular Two-Phase Flow Considering the Four Involved Mass Transfers

2012 ◽  
Vol 134 (8) ◽  
Author(s):  
Zahra Baniamerian ◽  
Ramin Mehdipour ◽  
Cyrus Aghanajafi
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Fluid Flow ◽  
Analytical Model ◽  
Two Phase Flow ◽  
Experimental Models ◽  
Analytical Models ◽  
Phase Flow ◽  
Two Phase Flows ◽  
Two Phase

Efficiently employing two-phase flows for cooling objectives requires comprehensive knowledge of their behavior in different conditions. Models, capable of predicting heat transfer and fluid flow trends in this area, are of great value. Numerical/analytical models in the literature are one-dimensional models involving with many simplifying assumptions. These assumptions in most cases include neglecting some mechanisms of mass transfer in two-phase flows. This study is devoted to developing an analytical two-dimensional model for simulation of fluid flow and mass transfer in two-phase flows considering the all mass transfer mechanisms (entrainment, evaporation, deposition and condensation). The correlation employed for modeling entrainment in this study, is a semiempirical correlation derived based on physical concept of entrainment phenomenon. Emphasis is put on the annular flow pattern of liquid vapor two-phase flow since this regime is the last encountered two-phase regime and has a higher heat transfer coefficient among other two-phase flow patterns. Attempts are made to employ the least possible simplification assumptions and empirical correlations in the modeling procedure. The model is then verified with experimental models of Shanawany et al., Stevanovic et al. and analytical model of Qu and Mudawar. It will be shown, considering pressure variations in both radial and axial directions along with applying our semiempirical entrainment correlation has improved the present analytical model accuracy in comparison with the accuracy of available analytical models.

Two-Position and Highly-Efficient Clamping Device Based on Lever-Toggle Force Amplifier Driven by Pneumatic Muscle

2011 ◽  
Vol 201-203 ◽  
pp. 2841-2845
Author(s):  
Lin Lu ◽  
Ming Di Wang ◽  
Kang Min Zhong
Keyword(s):  
Production Efficiency ◽  
Simple Structure ◽  
Power Transmission ◽  
Compressed Air ◽  
Clamping Force ◽  
Pneumatic Muscle ◽  
Pneumatic Muscles ◽  
Output Force ◽  
Design Idea ◽  
Clamping Device

The clean compressed air is taken as power transmission medium in pneumatic clamping devices, and when cutting after clamping the workpiece, the energy are not consumed any more. So it can be said that it is a green clamping technology. However, a low pressure of pneumatic driving makes a lot of pneumatic fixtures too bulky in size.A new innovation design idea of clamping mechanism based on pneumatic muscle and the eternallever-toggle force amplifier is described in this paper, in which the pneumatic muscle is instead of traditional rigid cylinder. The pneumatic muscle has some features such as extremely simple structure, good flexibility, the big ratio of output force and diameter/weight, etc. Thus, this device can get much greater clamping force on the condition of reducing the size and weight of the structure definitely. In addition, using two pneumatic muscles alternately, it can enable the time of processing a workpiece to overlap with the time of unloading another workpiece, and which can improve the production efficiency significantly.

Study Concerning the Hysteresis of Pneumatic Muscles

2016 ◽  
Vol 841 ◽  
pp. 209-214 ◽  
Author(s):  
Tudor Deaconescu ◽  
Andrea Deaconescu
Keyword(s):  
Control Systems ◽  
Hysteresis Loops ◽  
Experimental Results ◽  
Pneumatic Muscle ◽  
Pneumatic Muscles

A known phenomenon during the contraction/expansion cycles of pneumatic muscles is the occurrence of hysteresis, caused by the elasticity of their component materials. The inherent hysteresis manifest in pneumatic muscles increases the non-linearity of the systems they are included in and consequently the complexity of the related control systems. The paper discusses a number of experimental results obtained for the hysteresis related behaviour of a small size Festo pneumatic muscle, where the specific hysteresis loops were highlighted via isotonic testing.

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