Design of Adaptive Fuzzy PID Controller for Electropneumatic System

The purpose of the study is to develop an adaptive electropneumatic automatic system based on the classical PID controller using modern technology for controlling like fuzzy controlling. The need of an adaptive setting occurred because of the fact that the classic controller has high sensitivity towards interferences with the main signal and the need for the parameters to be regulated often and be done by hand. Another reason is the inability to provide optimal parameters for the controller for nonlinear processes and changes of the parameters in time. In this article the work of electropneumatic system with linear actuator, is examined. A mathematical model describing the dynamics of the processes, is developed. An adaptive fuzzy PID controller with variable coefficients is synthesized. The system is studied in the environment of Matlab Simulink. The transient processes in the system are compared to processes where the classical PID controller. The results are presented in graphical form.

METHODS OF CONTROL OF MEASURING BALLAST WATER IN TANKS DURING THE LOADING OF THE SHIP AND THEIR INFLUENCE ON THE CALCULATION OF INCOMING CARGO

In transportation bulk cargo by the sea vessels weight of the cargo loaded in specified amount can be determined by both land measuring facilities and ship draught. In terms of the study there has been offered a comparative characteristics of different methods of measuring ballast water: manual measuring and use of automatic gauging (the system of pressure gauges MAS 2600 and electropneumatic system LevelDatic 80S). Errors occurring in the measuring process were studied. The article presents a technique to control measuring ballast waters while loading. The results of the analysis of water level in ballast tanks allow to evaluate possible losses of a consignee for any given type of vessel, and require to provide strict control over cargo loading in order to guarantee safe navigation and economic effectiveness of cargo operations.

Adaptive Moving Sliding Mode Control for SISO Systems: Application to an Electropneumatic System

This paper aims to propose and develop an adaptive moving sliding mode controller (AMSMC) that can be applied for nonlinear single-input single-output (SISO) systems with external disturbances. The main contribution of this framework consists to overcome the chattering phenomenon problem. The discontinuous term of the classic sliding mode control is replaced by an adaptive term. Moreover, a moving sliding surface is proposed to have better tracking and to guarantee robustness to the external disturbances. The parameters of the sliding surface and the adaptive law are deduced based on Lyapunov stability analysis. An experimental application of electropneumatic system is treated to validate the theoretical results.

Subspace Identification of Hammerstein Model with Unified Discontinuous Nonlinearity

The main aim of this study is to handle the case where the structures of nonlinear systems are unknown. In the many works, the parametric identification of nonlinear systems represented by Hammerstein model, with discontinuous and asymmetric nonlinearity, considers the structures of the nonlinear and linear blocks are known, especially the nonlinear bloc. To solve this problem, a unified form of nonlinearity representing eight cases of nonlinearities can be used. The parameters of both blocks, linear and nonlinear, are estimated using an iterative subspace approach. More importantly, in an attempt to show the extent to which this method is efficient, we apply it to experimental data obtained from the electropneumatic system. As a result, the numerical and experimental examples confirm a good conditioning and computational efficiency.

Dynamic High-Gain Observer to Estimate Pneumatic Actuator Temperatures

This paper deals with the estimation of the actuator temperature in an electropneumatic system. First, an appropriate nonlinear system that accounts for the actuator temperature dynamics is introduced. Then in order to overcome the difficulty of installing temperatures sensors in each chamber of the actuator, two nonlinear high-gain observers are proposed to provide online estimate of these temperatures. The gain of both observers can be tuned by the choice of a scalar design parameter. However, the design parameter is constant for the first observer and its choice has to satisfy a compromise between an accurate estimation of the state estimation and a satisfactory sensitivity of the observer with respect to the unavoidable output noise measurements. This difficulty is overcome in the second observer since the scalar design parameter is time varying and is governed by a Riccatti differential equation. The involved adaptation process of the design parameter is mainly driven by the power of the output observation error norm computed on a moving horizon window. Simulation results are given to show the effectiveness of the proposed observers and in particular to compare the performance of both observers, namely, the accuracy of the respective estimates and their sensitivity with respect to noise measurements.