CAN-bus in a closed loop hydraulic position servo

CAN-bus is one of the most common data buses used in real time hydraulic control systems. The manufacturers of hydraulic components have also developed valves and accessories, which are available with CAN-bus interface. This paper concentrates on the closed loop hydraulic position servo realised with CAN-bus. Four different solutions to realise an electrohydraulic position servo system are presented in this paper. The normal system without any CAN-bus is used as a reference system. The other three systems studied are: CAN-bus in the forward loop between the controller and the valve, CAN-bus in the feedback loop between the position transducer and the controller and CAN-bus in the forward and feedback loops. State controller is used in each case, The influence of the sampling time, the baud rate of CAN-bus and the data transfer delays are studied and compared.