Static Force Model-Based Stiffness Model for Pneumatic Muscle Actuators

2015 ◽  
Vol 18 ◽  
pp. 207-214 ◽  
Author(s):  
József Sárosi ◽  
Ján Piteľ ◽  
Jaroslav Šeminský
Keyword(s):  
Variable Stiffness ◽  
Relative Displacement ◽  
Time Variable ◽  
Force Model ◽  
Power Weight ◽  
Static Force ◽  
Pneumatic Muscle ◽  
Stiffness Model ◽  
Muscle Actuators ◽  
And Control

Pneumatic muscle actuators (PMAs) differ from general pneumatic systems as they have no inner moved parts and there is no sliding on the surfaces. During action they reach high velocities, while the power/weight and power/volume rations reach high levels. The main drawbacks of PMAs are limited contraction (relative displacement), nonlinear and time variable behaviour, existence of hysteresis and step-jump pressure (to start radial diaphragm deformation) and also antagonistic connection of PMAs to generate two-direction motion. These make PMAs difficult to modelling and control. In this paper a new stiffness model and the variable-stiffness spring-like characteristics are described and tested using two Fluidic Muscles made by Festo Company. The muscles have the same diameter, but different length.

scholarly journals Comparison of static force exerted by fluidic muscle and shadow air muscle

2015 ◽  
Vol 9 (2) ◽  
pp. 15-19
Author(s):  
József Sárosi ◽  
László György
Keyword(s):  
Applied Pressure ◽  
Relative Displacement ◽  
Static Force ◽  
Contraction Force ◽  
Pneumatic Muscle ◽  
Pneumatic Muscles ◽  
Load Carrying ◽  
Air Muscle ◽  
Fluidic Muscle ◽  
Muscle Actuators

Many researchers have investigated different properties and behaviour of pneumatic muscles actuators (PMAs). Most of them have dealt with the force-contraction (force-relative displacement) characteristics or control of PMAs. In this paper two different type PMAs are compared: Fluidic Muscle made by Festo Company and Shadow Air Muscle made by Shadow Robot Company. The most relevant difference between them can be noticed in their structure. The Fluidic Muscle is an embedded muscle which means the load carrying element is embedded in its membrane, while Shadow Air Muscle is a netted muscle, but in its non-loaded condition there is a gap between the membrane and the load carrying element. Among other things, force developed by pneumatic muscle actuators depends on applied pressure, contraction, geometry and the used materials. As it is described in this paper, they show significantly different force-contraction characteristics despite having similar dimensional properties. These characteristics are determined by experimental measurement.

Novel Considerations on Static Force Modeling of Pneumatic Muscle Actuators

2016 ◽  
Vol 21 (6) ◽  
pp. 2647-2659 ◽  
Author(s):  
George Andrikopoulos ◽  
George Nikolakopoulos ◽  
Stamatis Manesis
Keyword(s):  
Static Force ◽  
Pneumatic Muscle ◽  
Force Modeling ◽  
Muscle Actuators

scholarly journals HUmanoid Robotic Leg via pneumatic muscle actuators: implementation and control

Meccanica ◽  
2017 ◽  
Vol 53 (1-2) ◽  
pp. 465-480 ◽  
Author(s):  
George Andrikopoulos ◽  
George Nikolakopoulos
Keyword(s):  
Pneumatic Muscle ◽  
Muscle Actuators ◽  
Robotic Leg ◽  
And Control

Static Modeling of Braided Pneumatic Muscle Actuator: An Amended Force Model

2021 ◽  
Author(s):  
Saswath Ghosh ◽  
Deepak Kumar ◽  
Sitikantha Roy
Keyword(s):  
Power System ◽  
Applied Pressure ◽  
Static Model ◽  
Force Model ◽  
Static Force ◽  
Pneumatic Muscle ◽  
Deformation Response ◽  
Static Modeling ◽  
Pneumatic Muscle Actuator ◽  
Practical Feasibility

Abstract 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.

Precise dynamic modeling of pneumatic muscle actuators with modified Bouw–Wen hysteresis model

2021 ◽  
pp. 095440892110080
Author(s):  
Mohammad Sheikh Sofla ◽  
Mohammad Zareinejad
Keyword(s):  
Weight Ratio ◽  
Muscle Length ◽  
Control Procedure ◽  
Force Model ◽  
Hysteresis Model ◽  
Restoring Force ◽  
Pneumatic Muscle ◽  
Hysteresis Nonlinearity ◽  
Asymmetric Force ◽  
Muscle Actuators

Pneumatic muscle actuators (PMAs) are frequently used in a wide variety of biorobotic applications, such as robotic orthoses and wearable exoskeletons, due to their high power/weight ratio and significant compliance. However, the asymmetric hysteresis nonlinearity reduces their fidelity and cause difficulties in the accurate control procedure. In this paper, Bouc–Wen hysteresis model is modified to describe the asymmetric force/length hysteresis of the PMA. The effect of muscle length on hysteretic restoring force is considered in this modified model and experimental results show that the proposed model has a better performance to characterize the asymmetric hysteresis loop of pneumatic muscles. The nonlinear pressure/force model of these actuators also is modeled precisely and its performance is experimentally verified for different muscle lengths.

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