Sampling time adaptive control methodology for CAN-based Networked Control Systems

Networked Control Systems (NCS) have become a widely considered research topic. This new control approach differs from the traditional fieldbus systems in that the controller and the plant are physically separated and connected through an industrial network. The major challenge of NCS design is the limited data feedback using the communication network (network delays and packet loss), which can degrade the NCS performance or even cause instability. For CAN-based NCS, another important issue is the correct selection of the messages sampling times. In order to mitigate these problems, control methodologies have been developed based on different types of network protocols in conjunction with different strategies to handle the degenerative effects related to NCS. This paper describes our approach to design and evaluate a new control methodology for application in CAN-based NCS. The solution is based on an adaptive PID controller that automatically manages the NCS sampling time, reducing the network utilization rate while maintaining NCS performance and stability. The feasibility and effectiveness of the control methodology are outlined through experimentation on a CAN-based NCS platform, showing significant results in the CAN network utilization reduction.