Real-Time Software-In-The-Loop Simulation For Control Education

This paper suggests a real-time implementation method for software-in-the-loop (SIL) simulation for control systems, primarily for control education. The SIL simulation is carried out by using a PC for the controllers, a PC for the plant, an open network, and a general-purpose computer-aided control system design (CACSD) package. Specially, Ethernet network is investigated in terms of control issues such as sampling interval, network-induced time-delay, use with many I/O points and data synchronization. A performance evaluation of software-in-the-loop simulation is made with respect to a computation delay and a sampling interval. To reduce the effects of the time-delay, particularly for fast plants, we introduce a time-scaling method that leads to a slow motion. It is demonstrated that this real-time SIL simulation will be very useful, particularly for control education.