Stamatis Manesis

A Survey of Applications of Wireless Sensors and Wireless Sensor Networks

Wireless sensors and wireless sensor networks have come to the forefront of the scientific community recently. This is the consequence of engineering increasingly smaller sized devices, which enable many applications. The use of these sensors and the possibility of organizing them into networks have revealed many research issues and have highlighted new ways to cope with certain problems. In this paper, different applications areas where the use of such sensor networks has been proposed are surveyed

A Survey on applications of Pneumatic Artificial Muscles

The aim of this article is to present a survey on applications of Pneumatic Artificial Muscles (PAMs). PAMs are highly non-linear pneumatic actuators where their elongation is proportional to the interval pressure. During the last decade, there has been a significant increase in the industrial and scientific utilization of PAMs due to their advantages such as high strength and small weight, while various types of PAMs with different technical characteristics have been appeared in the relative scientific literature. This article will summarize the key enabling applications in PAMs that are focusing in the following areas: a) Biorobotic, b) Medical, c) Industrial, and d) Aerospace applications.

Intelligent control of wastewater treatment plants

In recent years intelligent control of large-scale industrial processes has brought about a revolution in the field of advanced control. Knowledge-based techniques which use linguistic rules elicited from human experts are at the core of this class of systems, of which fuzzy and neural controllers are two examples that have been applied with success. This paper presents an intelligent control system which can be embedded in a commercial programmable logic controller for the control of wastewater treatment plants.

Piecewise Affine Modeling and Constrained Optimal Control for a Pneumatic Artificial Muscle

In this paper, the modeling and control problem of a pneumatic artificial muscle (PAM) is being considered. The PAM is an actuator characterized by a decrease in the actuating length when pressurized. Its nonlinear nature and time-varying parameters cause difficulties in modeling their characteristics, as well as in designing controllers for high-performance positioning systems. A constrained linear and piecewise affine system model approximation is formulated, and a control scheme composed of the following is being synthesized: 1) a feedforward term regulating the control input at specific set points and 2) a constrained finite-time optimal controller handling any deviations from the systems equilibrium points. Extended experimental studies are utilized to prove the efficacy of the suggested controller.

A survey on pneumatic muscle actuators modeling

The aim of this article is to provide a survey on the most popular modeling approaches for Pneumatic Muscle Actuators (PMAs). PMAs are highly non-linear pneumatic actuators where their elongation is proportional to the interval pressure. During the last decade, there has been an increase in the industrial and scientific utilization of PMAs, due to their advantages such as high strength and small weight, while various types of PMAs with different technical characteristics have been appeared in the literature. This article will: a) analyze the PMAs operation from a mathematical modeling perspective, b) present their merits and drawbacks of the most common PMAs, and c) establish the fundamental basis for developing industrial applications and conducting research in this field.

Flatness Conservation in the n-trailer System Equipped with a Sliding Kingpin Mechanism

Nonlinear systems, which are differentially flat, have several properties that can be useful on designing effective controllers. In this paper we show that the n-trailer system equipped with a sliding kingpin mechanism is a differentially flat system, like its non-sliding kingpin counter part. The sliding kingpin technique is used to eliminate the undesired deviation of the path of each intermediate vehicle from that of the leading one (off-tracking phenomenon). The linearizing outputs of the flat system are the Cartesian coordinates of the middle of the last semi-trailers axle. The state space and the kinematic equations of the new modified system are derived and the conditions for flatness are examined. The flatness conservation is also checked relatively to several kinds of dynamic sliding feedback control.

On the Suppression of Off-tracking in Multi-articulated Vehicles through a Movable Junction Technique

The motion of a multi-articulated robotic vehicle as well as of a train-like vehicle is characterized by the deviation of the path of each intermediate vehicle from that of the leading one (off-tracking phenomenon). In this paper, we propose the use of an innovative movable junction, which allows the kingpin to slide along the rear axis of the pulling vehicle, a technique that proved to be efficient in reducing or completely eliminating off-tracking. New kinematic equations are derived and a nonlinear controller is analytically developed, based on the steady-state off-tracking behavior of the n-trailer system. Simulations and a comparison study for various cases without/with this innovative “sliding kingpin” junction technique showed that its use together with an analytically derived controller can make possible the elimination of off-tracking.

Off-Tracking Elimination in Road Trains of Heavy Duty Trucks with Multiple Semi-Trailers

Abstract The implementation of road trains consisting of multiple hooked semi-trailers presents mechanical realization and traffic related problems. Among these problems, the most basic is the off-tracking problem. This paper proposes a solution based on a kingpin sliding technique, that allows articulated semi-trailers to follow exactly the tractors path. Simulation results showed that, for highway paths, the off-tracking deviation is completely eliminated.

An experimental study on thermodynamic properties of Pneumatic Artificial Muscles

In the past fifty years, several attempts have been made to model the characteristics of Pneumatic Artificial Muscles (PAMs). PAM models based on their geometrical properties are the most commonly found ones in the scientific literature. In the process of deriving those models a lot of assumptions and simplifications are made due to the fact that PAM is a highly non-linear form of actuation. The purpose of this study is to propose additional considerations for future model improvements that will augment the overall model accuracy, and will best describe the relationship between force, displacement and non-linear thermal properties of PAM actuators through extensive observation and analysis of its thermodynamic characteristics during long-run operation experiments. In this article multiple experimental results will be presented that prove the relation between the thermodynamic properties of the PAMs, especially in iterative operations, and the accuracy on the muscles force-prolongation relationship.

A switched system modeling approach for a Pneumatic Muscle Actuator

The aim of this article is to present a switched system approach for the dynamic modeling of Pneumatic Muscle Actuators (PMAs). PMAs are highly non-linear pneumatic actuators where their elongation is proportional to the interval pressure. During the last two decades, various modeling approaches have been presented that describe the behavior of PMAs. While most mathematical models are characterized by simplicity and accuracy in describing the attributes of PMAs, they are limited to static performance analysis. Static models are proven to be insufficient for real time control applications, thus creating the need for the development of dynamic PMA models. A collection of experimental and simulation results are being presented that prove the efficiency of the proposed approach.