Contour Tracking And Synchronization Control Of Networked Multi-axis Motion Systems

Contour tracking and synchronization control of multi-axis motion systems are one of the important topics in the field of motion control of modern intelligent manufacturing systems,and have found applications in a variety of areas,such as CNC machine tools,industrial robots,shaftless printing machines,textile machines,and other industries.The development and introduction of Ethernet technology make the motion control systems have many advantages,such as simple wiring,reduced coupling,modular modularity,easy expansion,and easy maintenance.The use of network instead of PCI card to achieve multi-axis motion control architecture has become a mainstream trend.Therefore,it is of great practical significance to study the networked motion control systems.At present,in addition to the traditional PID control,there are many advanced control algorithms for multi-axis motion control,such as neural network fuzzy control,sliding mode variable structure,H? control,and active disturbance rejection control,etc.However,the introduction of Ethernet technology into motion control systems brings new problems,such as the network-induced delay and packet loss caused by Ethernet non-deterministic communication mechanisms,which can reduce the control performance of multi-axis motion systems.At the same time,the influence on system control performance of system coupling and external loads cannot be ignored.Also,the contour tracking and synchronization control of the multi-axis motion systems are common and important problems.Therefore,the paper will study the problems of multi-axis contour tracking and synchronization control under the influence of the above uncertain factors and establish a set appropriate theories and methods.By changing the physical structure and communication scheduling,a universal Ethernet-based architecture of multi-axis motion control systems has been explored.In the existing communication mode,the control strategy is used to compensate for the impact of the network.At the same time,the PC-based software controller is developed,and it doesn't need to configure additional hardware modules.It can reduce the development cost and increase the universal performance of the system.From above,this paper mainly focuses on universal Ethernet-based the contour tracking and synchronization control of multi-axis motion systems.The main research work is as follows:(1)Owing to the application of conventional algorithms to achieve the control of the networked motion system,it cannot get satisfactory control performance,and then the demand analysis of the networked motion control system is given.On this basis,a set of universal Ethernet-based multi-axis motion system experimental platforms were designed,and a client software and an embedded server software with good human-computer interaction interface were developed.By analyzing the causes,especially the uncertainties such as delays caused by the network,it is necessary to design appropriate control algorithms to compensate for the impact of these uncertainties and other disturbances on system performance.The designed experimental platform has good scalability and versatility and can conveniently carry out experiments on various multi-axis motion control algorithms to verify the effectiveness and feasibility.Based on the platform,the second-order model parameters of the servo system are obtained through experimental identification,and the measurement methods and measurement results of the network-induced delay are given.Further,two cases that the known and unknown parameters of the local servo system model are considered,respectively,and the uncertainty of the system model caused by the network time-varying delay is modeled as part of the total system disturbance.Moreover,a multi-axis motion control system model is established,which is the foundation for the design of subsequent algorithms.(2)In the case that the parameters of the local servo system are unknown,and a contour tracking control algorithm based on linear active disturbance rejection control(LADRC)and fuzzy PID is proposed for multi-axis motion contour tracking control system with network-induced time-varying short delay.First,the uncertainty caused by the network time-varying delay was modeled as a part of the total disturbance of the system.Then,the linear extended state observer(LESO)based LADRC was designed to implement the estimation and compensation of the total disturbance and reduce its impact on the system.Next,a cross-coupling controller(CCC)based on fuzzy PID is designed to achieve better contour tracking performance.The proposed method does not need to consider the system model parameter information and has a simple structure,which has certain practical application value.(3)In the case that the parameters of the local servo system are known,and a generalized extended state observer(GESO)and model predictive control(MPC)based contour tracking control method was proposed for a multi-axis motion contour tracking control problem with network-induced short time-varying delays.First,by decomposing the network-induced delay into the steady part and the uncertainty part,and the uncertainty part was modeled as a part of the total disturbance of the system.Then,the GESO based MPC is designed to estimate and compensate for the total disturbance of the system and reduce its impact on the system.Moreover,the stability analysis is given.Finally,a PID-based CCC is designed to achieve better contour tracking performance.(4)In the case that the parameters of the local servo system are unknown,a LADRC-based position synchronization control method is proposed for a multi-axis motion position synchronization control problem with network-induced long and short time-varying delays.Based on the establishment of a synchronization coupling error model,the uncertainty caused by the network time-varying delay is modeled as a part of the total disturbance of the system.The LESO based LADRC is designed to implement the estimation and compensation of the total disturbance and reduce its impact on the system.It can achieve a good position synchronization control performance.Finally,the stability conditions of the synchronization control system were given.The proposed method does not need to consider the system model parameter information and has a simple structure,which has certain practical application value.(5)In the case that the parameters of the local servo system are known,a GESO-based position synchronization control method is proposed for a multi-axis motion position synchronization control problem with network-induced short time-varying delays.Based on the establishment of a synchronization coupling error model,the network-induced delay is decomposed into a steady part and an uncertainty part and the uncertainty part is modeled as a part of the total disturbance of the system.Then,a position synchronization controller based on GESO is designed to achieve the estimation and compensation of the total disturbance and reduce its impact on the system.It can achieve good position synchronization control performance.Finally,the stability conditions of the synchronization control system were given.A series of experiments were carried out on the designed experimental platform to verify the effectiveness and feasibility of the proposed algorithms.Finally,the paper was summarized,and the problems that need further research prospect.