Optimization of transient processes of the pneumatic servo drive taking into account the friction model with the Stribeck effect

Abstract

The aim of the work is to select the optimal values of the parameters of the digital PID controller to eliminate self-oscillations in systems, as well as to optimize the type of transient processes of the servo pneumatic drive. The reason for the study was the problem of the occurrence of self-oscillations in pneumatic systems when using friction models that are closest to reality. The scientific novelty of the article consists in the creation of a computer model and the application of optimization methods to improve the quality of transient processes of the pneumatic servo drive, taking into account the Striebeck friction model. The authors of the article optimized the transient processes of the pneumatic servo drive taking into account the selected friction model. The optimal parameters of the PID controller were selected using computer simulation. And the instability of the system was eliminated as well. To optimize the system performance, the gradient descent method was chosen. An assessment of the quality indicators of transient processes before and after optimization was made. Based on the simulation results of the pneumatic servo drive system, it can be concluded that the gradient descent method can be used to determine the parameters of the PID controller. The transition from an analog (continuous) system to a digital (discrete) system has been made It is necessary to determine the sampling period for its implementation. The article indicates the main methods for determining the sampling period and shows the disadvantages of these methods. Analysis of the results shows that the methods described in the article should be used only for the first approximation, and the value of the indicated quantity should be selected from the calculation of the minimum error between an analog (continuous) and digital (discrete) system. An error of less than 1% allows the selection of a programmable logic controller. The topic of the article is relevant for scientific research and includes the provision of practical recommendations for determining the parameters of a digital PID controller and selecting a controller for specialists who are inloved in the design of systems that include a pneumatic servo drive.