Research On NC-Link Protocol Proxy Service And Cluster Technology

As a protocol used to realize the interconnection between different CNC equipment,CNC equipment interconnection protocol is the key to realize the industrial intelligent manufacturing.At present,the main trend foreign CNC equipment interconnection protocols are MT-Connect in the United States and OPC UA in Europe,while there is NC-Link in the application test stage in China.In order to make NC-Link can be applied in complex factory environment,the thesis designs the NC-Link protocol proxy and cluster scheme by using proxy technology and cluster technology,which provides necessary security communication guarantee and availability for NC-Link system.First of all,based on the proxy technology,the thesis designs the NC-Link proxy service scheme,which provides message broker service,data encryption proxy service and user authentication proxy service for NC-Link.These services can not only ensure the privacy and integrity of data transmission between application systems and NC-Link proxy servers,but also provide security guarantee for CNC equipment.Then,in order to make the NC-Link system have the necessary availability and scalability,the thesis uses the cluster technology to design the NC-Link proxy server cluster,so that the NC-Link proxy server cluster can deal with the single point of failure in the proxy layer.In addition,based on the weighted round-robin scheduling algorithm,the thesis designs a load balancing algorithm for NC-Link proxy server cluster.The algorithm can adjust the scheduling strategy according to the real-time status of the background NC-Link message brokers,so as to achieve the load balance of the NC-Link proxy server cluster.Finally,the NC-Link proxy service and cluster scheme are implemented and tested.The test results show that the NC-Link proxy service and cluster scheme can not only provides message broker service,data encryption proxy service,and user authentication proxy service for NC-Link,but also deal with the single point failure of the proxy layer.When a proxy server in the proxy cluster fails,the whole NC-Link system can still operate normally.When the NC-Link system load is heavy,the improved load balancing algorithm is better than the weighted round-robin scheduling algorithm and weighted least connection scheduling algorithm on load balancing.