Research On Control Distribution Technology Of Distributed System

Distributed control systems exist in a wide range of industrial control systems,such as advanced machinery manufacturing equipment,automotive control systems,industrial robots,hydraulic drives system and so on.In recent years,with the continuous development of "Made in China 2025" strategy,the machinery manufacturing industry with intelligent manufacturing as the core has been booming.The distributed control system with network,information and intelligence has been widely used in the traditional manufacturing industry.At the same time,the coordination strategy of each subsystem as a key issue in the design and analysis of DCS has also become one of the research hotspots in the field of electromechanical control.This paper studies cooperative control technology among DCS subsystems based on control allocation strategy.The main research work of this dissertation includes:(1)For the linear parameter-varying over-actuated systems,considering the impact of the time varying parameter real-time perturbation on the system performance,by using the robust optimization theory,the original control allocation optimization problem which cannot be solved is transformed into a second-order cone programming model problem which can be solved by mature methods.Then the suppression of time-varying parameter perturbation is achieved by the allocation process.In addition,a robust control allocation fault-tolerant algorithm is designed by considering the actuator failure.Finally,through the simulation and analysis of steering system of four-wheel steering vehicle,the results show that the robust control allocation algorithm can effectively reduce the time-varying parameter perturbation and motor failure on the impact of the vehicle handling stability,make front-rear wheel comers more reasonable allocation,with more robustness.(2)Aiming at the problems with cooperative control of subsystems in DCS,considering the influence of subsystem's dynamic characteristics on DCS cooperative control objectives,based on the research results of the above-mentioned robust control allocation technology,the LMI convex optimization problem is designed to obtain the dynamic control distribution gain matrix satisfying set constraint target and the process of optimizing the allocation of each subsystem control input is realized.In addition,by considering the sensor failure of some subsystems,we design and improve the dynamic control allocation strategy to achieve fault-tolerant of DCS.By using the four-corner leveling system simulation analysis of the hydraulic press,the results show that,the proposed dynamic control allocation algorithm and improved fault-tolerant algorithm can effectively suppress the adverse effects of pressure fluctuation or sensor failure of hydraulic subsystems on the leveling system,the cooperation of each hydraulic subsystem is more reasonable and the leveling accuracy is higher.(3)Aiming at the stability of DCS closed-loop system based on the above-mentioned dynamic control allocation algorithm,using Lyapunov stability theory,small gain theory,dissipation theory,etc.,the discriminant conditions for DCS closed-loop stability are obtained,respectively;and based on the design of the upper-level control law with a certain stability margin and the upper-level control law of dynamic output feedback,the stability conclusion of the DCS closed loop system is obtained.Finally,the work of the full text is summarized,and the direction of the next research is pointed out.