Classical Proportional Integral Derivative Controller Research Articles

Neural Control of the Movements of a Wheelchair

This paper studies the problem of controlling the movements of a handicapped person‘s motorized wheelchair from a practical point of view. The control system implemented has been divided into two levels: the “low level”, consisting of an electronic system which directly controls the drivers of the chair‘s motors, with a classic PID (proportional-integral-derivative) control loop. The aim of this level is to ensure that the speeds of each one of the wheels is similar to the input speed of these control boards. The second control level (“high level”), implemented by means of neural techniques, ensures that the linear and angular speeds of the wheelchair are those indicated by a trajectory generator. A new recurrent model is used as the neural network, for which the stability conditions of the complete control system are obtained and various practical tests are carried out, which show the correct performance of the actual system implemented.

Linguistic PID Controllers

A class of linguistic controllers is derived using the combination of classical PID (proportional-integra l -derivative) control ideas and fuzzy set theory. Six different types of such controllers are proposed and their basic characteristics investigated and discussed. A fuzzy scaling technique is suggested for the reduction of off-line computational requirements. Simulation results are presented for comparing the performance of the controllers proposed, and to illustrate the advantages of such fuzzy PID controllers over that of the conventional PID controller.

Controller tuning for a slow nonlinear process

Determining the tuning constants of a classical PID (proportional-integral-derivative) controller for a slow nonlinear process, such as the temperature loops on a heat-treat of annealing furnace, can be a laborious task. Several tuning methods were considered to identify a method that could be applied easily in the field with limited resources. The method of Ziegler and Nichols (1942) proved to easy and effective. Results obtained by using the Ziegler-Nichols open-loop method to determine the tuning constants for a classical PID temperature controller for a heat-treat furnace are described. The process being controlled is described, and open-loop test data are presented. >