Abstract
In Networked Control Systems (NCS) data are communicated through networks which are subjected to damage or loss, resulting in an unstable system. To deal with issue of missing feedback/input (error (u-feedback)) data in a closed loop control system a discrete PID controller is designed. Cubic spline interpolation is used to estimate the missing input (error) values. The simulations show that the estimated values are fairly accurate. The method is then verified with the performance of First order, Third order and Fourth Order systems.