A position compensation method of ethercat bus

Abstract

The invention discloses an EtherCAT bus position compensation method, which includes a bus fault observer, a motion state buffer module and a position increment prediction module. The bus fault observer detects the timing relationship between DC interruption and PDI interruption of a servo slave station. , these two interrupts have a one-to-one correspondence relationship. The motion state cache module saves the state of the bus during normal operation, including position increment, acceleration and jerk. When the bus fails, according to the acceleration at the previous moment Calculate the current acceleration with the jerk, and calculate the current position increment based on the current acceleration and the position increment at the previous moment. This position increment will be given to the position loop as the input of the position loop; at the same time, the predicted acceleration and position increment will be cached. . By caching the position increment data when the bus is normal, the most likely position increment can be predicted when the bus fails, preventing the slave station from being affected by the bus failure caused by external interference, causing motor vibration or even mechanical failure.

Description

technical field [0001] The invention relates to the technical field of motor drive and motion control, in particular to an EtherCAT bus position compensation method. Background technique [0002] EtherCAT is the abbreviation of Ethernet for Control Automation Technology. It is an open network communication protocol between master station and slave station based on real-time Ethernet developed by BeckhoffAutomation GmbH and managed by ETG (EtherCAT Technology Group) organization. Currently EtherCAT has become a widely used bus communication protocol. [0003] EtherCAT is a high-speed field bus protocol based on Ethernet. It uses UDP to encapsulate the EtherCAT protocol into UDP / IP data packets, and uses a fixed bus cycle for data refresh. During the synchronization process of the EtherCAT protocol, the local clock of the first slave station will be obtained as the reference clock of the entire bus. All slave stations on the entire bus, including the master station, will adj...

AI Technical Summary

Problems solved by technology

At this time, if the data frame is damaged due to external electromagnetic interference and other reasons, the target position of a certain period is not updated to the slave station. At this time, the slave station will generate a sudden change in the position command, causing the vibration of the servo operation, and the servo slave station will Abnormal noise may occur when running at low speed, and may cause alarm when running at high speed, and even cause machine damage or safety accidents in severe cases

[0006] In order to solve this problem, the lost frame retransmission function can be added to the master station. However, there are many EtherCAT master stations from various manufacturers on the market, and many master stations do not have this function. In order to improve the anti-interference ability and stability of the servo slave station, there are also For the compatibility of each master station, this problem must be dealt with

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