PID Controller as a Platform for Implementation of the Adaptive Laws of the Electric Drive Control

Innovations in designing of the algorithmic supply of the moving control systems, based on the ideas of the inverse dynamic problem and local optimization, lead to analytic expressions for the automatic control laws of the dynamic objects with an incomplete description or with the parameters, which may be essentially changed during operation. The controllers, which implement such control laws, provide a closed loop system of the adaptive properties, and their structural interpretation allows us to see a familiar outline of a traditional PID controller. This gives us a chance to realize the new adaptive control laws for the existing DC electric drives equipped with the traditional PID controllers. Thus, the procedure of changing of the control law results in new parameters of setting of PID controller in the electric drive. In this paper the authors adhere to the concept of a direct adaptation, current numerical optimization for the local criterion of the main loop of the control system. The main problem of such an approach is to summarize the control error containing the data about all the uncontrolled changes of the object characteristics and environment included into the chosen optimization criterion. This problem is solved by introduction of a generalized control error as a difference between the derivative controlled coordinate and the respective derivative variable of the model reference, and by the use of the local quadratic criterion. Application of the new technology is demonstrated by construction of the control law for the adaptive controller of the electric drive designed to control the speed of DC motor with an independent excitation in the conditions of the uncontrollable change of its parameters and shaft load. Therefore, the aim is construction and investigation of the adaptive control laws, and designing on its basis of an appropriate structure available for use of the traditional PID controller platform, and also the synthesis of its parameters determining the desired static and dynamic properties of the projected electric drive. The authors present a statement and a solution to this problem. They demonstrate that the designed adaptive control law can be implemented on a conventional PID controller platform. At the same time, a traditional PID controller is converted into an adaptive one simply by changing of the parameter of its tuning with a constant element structure including integrator, differentiator and amplifiers. The results are presented using the construction of the adaptive electric drive with the use of the virtual units of the power electronic elements and electric DC motors included into SIMULINK library.

адаптация, градиентный метод, закон управления, локальная оптимизация, адаптивный регулятор, ПИД регулятор, электропривод, adaptation, gradient method, control law, local optimization, adaptive controller, PID controller, electric drive

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