Modified MTS Algorithm And Co-design Of Scheduling And Control In Networked Control System

Networked Control System (NCS) is a distributed system which is the development and merging results of computer technology, communication technology and control technology, and the communication among sensor, actuator and controller in different areas occurs through a shared network. The control based on network results in a high communication rate, flexible architecture and shared network resources, even generally reduces the installation, reconfiguration and maintenance time and costs, which is especially adopted to remote control. However, the use of network also introduces several new challenges, such as network-induced delay, band-limited network, packet dropout and so on, which restrict the performance of NCS. Being the extension of computer network in the field of control and advanced development of control system and communication network, NCS has gained wide applications in practice. The co-design of scheduling and control in NCS is a key future direction, which needs further research.Firstly, the definition of NCS and essential problems are described in this paper, and the research progresses of NCS scheduling are also introduced, as well as the research methods in co-design of NCS scheduling and control; Then, according to the problems existing in present NCS simulation tools, the idea of a novel simulation platform called MS2 is proposed based on MATLAB and hybrid system theory, and its validity is also analyzed which proves that MS2 method is effective from the perspective of hybrid system theory.Then, according to the problems of the collision between real-time data and nonreal-time data existing in MTS algorithm, a modified MTS algorithm is proposed from three aspects, which are the definition of priority, allocation of free time in a sampling period and definition of sampling period, and the modified MTS algorithm is simulated through TrueTtime simulation toolbox. In three different conditions, simulation results show that the modified MTS algorithm results in better scheduling performance compared with MTS. According to the proper allocation of network resources, the modified MTS algorithm avoids the collision between real-time data and nonreal-time data, and it also keeps the network-induced delay smaller than a sampling period. Therefore, the system can be operated in a stable condition and the validity of the modified MTS algorithm is proved. Finally, GPC and EDF scheduling algorithm are adopted to the NCS co-design research, and the co-design method considers both the NCS scheduling performance and control performance, then the process of the general co-design method is also given. From the TrueTime simulation results based on a NCS with three loops of DC-motors, NCS under co-design compared with NCS without co-design, the former shows better control performance and scheduling performance, and a better anti-jamming ability and network adaptive ability, so the NCS with co-design is guaranteed to operate in an optimal state.