József Sárosi

New approximation algorithm for the force of Fluidic Muscles

The newest and most promising type of pneumatic actuators is the pneumatic artificial muscle (PAM). Different designs have been developed, but the McKibben muscle is the most popular and is made commercially available by different companies (e. g. Fluidic Muscle manufactured by Festo Company). Pneumatic artificial muscles have a wide range of use in industrial and medical fields. There are a lot of advantages of these muscles like the high strength, good power-weight ratio, low price, little maintenance needed, great compliance, compactness, inherent safety and usage in rough environments. The main disadvantage is that their dynamic behavior is highly nonlinear. The most often mentioned characteristic of PAMs is the force as a function of pressure and contraction. In this paper our newest function approximation for the force generated by Fluidic Muscles is shown that can be generally used for different muscles made by Festo Company.

Accurate positioning of pneumatic artificial muscle at different temperatures using LabVIEW based sliding mode controller

Pneumatic artificial muscles (PAMs) are difficult to control because of their highly nonlinear and time varying nature, thus robust control method is needed. Sliding mode control can be favourably used for accurate positioning of PAMs. In this paper the error of sliding mode control based positioning of a Fluidic Muscle at different temperatures is determined. The controller is developed in LabVIEW and the error of the experiments shows 0.01 mm.

Accurate position control of PAM actuator in Lab VIEW environment

As an important driver element, the pneumatic artificial muscle (PAM) is widely used in industrial applications for many automation purposes thanks to their variety of advantages. The design of a stable robust position controller for PAM is difficult since it is a very nonlinear time-variant controlled plant because of the compressibility of air, air mass flow rate through the valve, etc. The main contribution of this paper is a robust position control method based on sliding mode for a robot arm, driven by pneumatic muscle actuator. Finally, it presents experimental results.

ELIMINATION OF THE HYSTERESIS EFFECT OF PAM ACTUATOR: MODELLING AND EXPERIMENTAL STUDIES

2), judder-free and resistant to dirt and dust, therefore these actuators are widely used in industrial environment besides electric motors or hydraulic actuators. One of the most mentioned drawbacks of PAMs is the existence of hysteresis. In this paper two experiments related to hysteresis phenomena of PAMs are described. The goal is to present a precise static force model for the hysteresis loop in the force-contraction (force-relative displacement) curve and a LabVIEW based sliding mode controller for hysteresis independent accurate positioning. Using the approximation algorithm for the force produced by the Fluidic Muscle the correlation coefficient R of nearly 1 and 0,01 mm accuracy in positioning is reached.

Model based open looped position control of PAM actuator

The Pneumatic Artificial Muscle (PAM) has great potential in industrial, robotic and prosthesis applications because of the extreme power to weight ratio, high strength and scalability for different purposes. However it is hard to control without precise modeling because of its high nonlinearity. In this paper we present our more accurate transfer function in comparison with other approaches. Finally we present the design and experimental testing of an open looped position controller for PAM actuator using the inverse of the transfer function.

Static Force Model-Based Stiffness Model for Pneumatic Muscle Actuators

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.

Mass customization model in food industry using industry 4.0 standard with fuzzy-based multi-criteria decision making methodology:

This article presents a new model of customized mass production management with Industry 4.0 standards within the food industry. The aim of this article is to develop a method for managing the production line where it is possible to produce an entire spectrum of products without reconfiguring the production line. An illustrative example is the production of fruit yoghurt of various types. The entire life cycle of the product is monitored and documentation of all relevant raw material data is carried out through the production process all the way to product packaging where each product is specifically marked with QR code. A special technique for deciding on optimum maintenance of the production line has been introduced and a multi-criteria decision model has been developed using the fuzzy analytic hierarchy process method where it is possible to achieve a high degree of minimization of maintenance costs. In this work, a fuzzy-based multi-criteria decision making methodology is developed for conceptual design evaluation in the cost reduction in maintenance of mass customization process. For the purposes of monitoring the production process itself, a LabVIEW application was created in the form of a SCADA system.

Axial vibration of an artificial muscle

Significant number of muscles can be assumed to be of longitudinal type where the length is much higher than its cross-section. Usual motion of the longitudinal muscles is axial due to its contraction and dilatation. Our aim is to investigate the axial vibration of such muscles. The artificial muscle is formed whose physical model is a clamped-free beam. Characteristics of the muscle material are obtained experimentally and the data are applied for the rheological model. It is obvious that the stress-strain properties are strong nonlinear. The beam is assumed to be fixed at one end and free for axial motion at the other end. Mathematical model of motion is supposed as a partial truly strong nonlinear differential equation. In the paper an analytical procedure for approximate solving of the equation is developed. Using a suitable transformation the equation is rewritten into two strong nonlinear ordinary second order differential equations. Analyzing the solution, the influence of the geometric properties, but also of material properties and boundary conditions on the motion is considered. Special attention is given to frequency of vibration of the beam. Effect of the order of nonlinearity and of the initial conditions on the frequencies is widely analyzed.

Investigation of accuracy of the newest function approximation for the force generated by pneumatic artifial muscle

The newest and most promising type of pneumatic actuators is the pneumatic artificial muscle (PAM). Different designs have been developed, but the McKibben muscle is the most popular and is made commercially available by different companies (e. g. Fluidic Muscle manufactured by Festo Company). The most often mentioned characteristic of PAMs is the force as a function of pressure and contraction. In this paper our newest function approximation for the force generated by Fluidic Muscles is shown that can be generally used for different muscles made by Festo Company.