Research On Real-time EtherCAT And Its Application For Multi-axis Montion

Recently, the multi-axis motion system has been widely applied to various fields,such as the high-speed printing, electronic assembly and intelligent robot. Currently, itsreal-time and synchronism property directly affects the quality and performance ofproducts. The traditional multi-axis motion network constructed based on fieldbus hasalready shown many defects in the speed and synchronization accuracy during longdistance transmission. Moreover, for a long time, there exist too many fieldbusstandards. The application of fieldbus has been seriously limited due to the difficulty ininterfacing with multi-vendor products. In light of this, to bring the real-time Ethernet intomulti-axis motion field will be a good solution to these problems, with its highbandwidth, high precision and better openness. These would be of great significance forfurther theoretical research and application prospects of networked multi-axis motionsystem.At the beginging, the paper focus on shortages of fieldbus, and then bring in thelatest industry Ethernet known as EtherCAT originally developed by Beckhoff aftercompared with other real-time Ethernet. Then, the operating principle and basis ofEtherCAT is presented in details from three aspects (EtherCAT Physical Layer,EtherCAT Data Link Layer and EtherCAT Application Layer). On this basis, a basiccommunication network has been constructed with master-slave mode. In the designer,functions of EtherCAT master are mainly accomplished by TwinCAT configurationsoftware and applications written in VC++. ADS (Automation Device Specification)router is adopted to realize communication between these two softwares. As toEtherCAT slave, after finishing the basic network constructed by Beckhoff’s terminal,the paper has proposesd a novel design method of multi-axis motion system (MMS). InMMS, Programmable system-on-chip device is employed as microprocessor center inconjunction with EtherCAT controller.They realize functions of complex stationtogether and are responsible for the control of multiaxial linkage. Besides, in order toobtain a more stable effect, subdivided driver and Plus deceleration planning isimplemented in the system. Finally, the paper has completed the capture of EtherCATpackets with netANALYZER which is a real-time Ethernet analyzer. Thanks to networkpacket analysis software--Wireshark, system performance analysis and testing are also carried out in the design. Experimental results show that the paper has realizedarchitecture design of EtherCAT network and remote data transmission. Due to itssuperior performance of high-speed and high synchronization accuracy, EtherCAT isvery suitable for precise control of multi-axis within long-distance.