Experimental investigation of characteristics of pneumatic artificial muscles

The characteristics of pneumatic artificial muscles (PAMs) make them very interesting for the development of robotic and prosthesis applications. The McKibben muscle is the most popular and is made commercially available by different companies. The aim of this research is to acquire as much information about the pneumatic artificial muscles as we can with our test-bed that was developed by us and to be able to adopt these muscles as a part of prosthesis. This paper presents the set-up constructed, and then describes some mechanical testing results for the pneumatic artificial muscles

Mesterséges pneumatikus izomelemek modellezése és paramétereinek szimulációja MATLAB környezetben

Pneumatic artificial muscles (PAMs) are becoming more commonly used as actuators in modern robotics. The most made and common type of these artificial muscles in use is the McKibben artificial muscle that was developed in 1950's. The braided muscle is composed of gas-tight elastic bladder, surrounded by braided sleeves. Typical materials used for the membrane constructions are latex and silicone rubber, while nylon is normally used in the fibres. This paper presents the geometric model of PAM and different MATLAB models for pneumatic artificial muscles. The aim of our models is to relate the pressure and length of the pneumatic artificial muscles to the force it exerts along its entire exists

Pneumatic Artificial Muscles (PAMs) Identification for Actuating a Wrist-Joint Rehabilitation Robot

Pneumatic Artificial Muscles (PAMs) are the most promising type of pneumatic-based actuators. Recently, they have been widely used in medical and rehabilitation robotic systems due to their flexibility, reliability, and high load-to-weight ratio. The aim of this work is to introduce an accurate mathematical model for describing the performance of the pneumatic artificial muscles under different applied pressures and loads by examining different previously proposed models. Being motivated by the muscles’ usage in a wearable robotic device for wrist rehabilitation where the required muscle force is not so large, it is interesting to consider the model that best expresses the muscle behavior over a lower range of the muscle force. An experimental system for measuring the muscle contraction at different applied pressures and loads is set up. Then, an algorithm for the parameters identification of the examined models based on the least squared error approach is developed using MATLAB Software

Function approximation for the force generated by different fluid muscles

The main disadvantage of the pneumatic artificial muscles (PAMs) is that their dynamic behaviour is highly nonlinear. Designing an adequate control mechanism for this highly non-linear system needs precise modelling. This paper presents our new, accurate and simple approximation model of PAM, comparing with measured and literary data

X-crossing pneumatic artificial muscles

Artificial muscles are promising in soft exoskeletons, locomotion robots, and operation machines. However, their performance in contraction ratio, output force, and dynamic response is often imbalanced and limited by materials, structures, or actuation principles. We present lightweight, high–contraction ratio, high–output force, and positive pressure–driven X-crossing pneumatic artificial muscles (X-PAMs). Unlike PAMs, our X-PAMs harness the X-crossing mechanism to directly convert linear motion along the actuator axis, achieving an unprecedented 92.9% contraction ratio and an output force of 207.9 Newtons per kilogram per kilopascal with excellent dynamic properties, such as strain rate (1603.0% per second), specific power (5.7 kilowatts per kilogram), and work density (842.9 kilojoules per meter cubed). These properties can overcome the slow actuation of conventional PAMs, providing robotic elbow, jumping robot, and lightweight gripper with fast, powerful performance. The robust design of X-PAMs withstands extreme environments, including high-temperature, underwater, and long-duration actuation, while being scalable to parallel, asymmetric, and ring-shaped configurations for potential applications

Positioning of pneumatic artificial muscle under different temperatures

Some researchers have mentioned that temperature creates an important part in the accuracy of positioning of pneumatic artificial muscles (PAMs). However, in literature investigations for measuring temperature inside and outside the PAMs have not been found. This paper presents our robust motion control of these muscle actuators under different temperatures using slidingmode control

Soft Wrist Exosuit Actuated by Fabric Pneumatic Artificial Muscles

Recently, soft actuator-based exosuits have gained interest, due to their high strength-to-weight ratio, inherent safety, and low cost. We present a novel wrist exosuit actuated by fabric pneumatic artificial muscles that can move the wrist in flexion/extension and ulnar/radial deviation. We derive a model representing the torque exerted by the exosuit and introduce a model-based optimization methodology for the selection of placement parameters of the exosuit muscles. We evaluate the accuracy of the model by measuring the exosuit torques throughout the full range of wrist flexion/extension. When accounting for the displacement of the mounting points, the model predicts the exosuit torque with a mean absolute error of 0.279 Nm, which is 26.1% of the average measured torque. To explore the capabilities of the exosuit to move the human body, we measure its range of motion on a passive human wrist; the exosuit is able to achieve 55.0% of the active biological range in flexion, 69.1% in extension, 68.6% in ulnar deviation, and 68.4% in radial deviation. Finally, we demonstrate the device controlling the passive human wrist to move to a desired orientation in the flexion/extension plane and along a two-degree-of-freedom trajectory.Comment: 16 pages, 15 figure