Fault detection and diagnosis method for bus communication in hydraulic support electro-hydraulic control system

The communication system is the channel and bridge for information transmission in the hydraulic support electro-hydraulic control system of the fully mechanized mining face. Currently, CAN bus is commonly used as the communication bus. It is susceptible to interference from the complex electromagnetic environment underground, resulting in internal communication hardware failures of the support controller and causing the phenomenon of "disconnection" of the controller. In addition, the CAN bus communication system adopts a multi master communication mode. The disconnection of a single controller will cause the entire electro-hydraulic control system to malfunction, posing a safety hazard. A CAN communication protection circuit has been designed to ensure stable operation of the communication system under high load conditions and strong anti-interference capability in complex environments. A fault detection and diagnosis method for CAN bus communication is proposed based on the CAN bus communication protocol combined with the token ring network concept. By designing the frame structure and fault detection method of data reasonably, the defect of difficult positioning of nodes when lost in CAN bus communication mode is compensated. The impact of increasing data length on transmission load is minimized to ensure good communication performance. Two end controllers are combined with six hydraulic support controllers to form a ring network. The upper computer issues commands from time to time to simulate the actual load situation of the bus during underground operation. The experimental verification of the bus communication fault detection and diagnosis method for the hydraulic support electro-hydraulic control system is carried out. The results show that this method has a low impact on the system load rate and will not affect the normal operation of the system. When a faulty node occurs, the faulty controller can be detected within 300 ms and an alarm can be sent to the entire working face, with a fault elimination rate of 100%.