One of the major challenges in Internet-based control
systems is how to overcome the Internet transmission delay.
In this paper, we investigate the potential of using the multirate
control scheme and the time-delay compensation to overcome the
Internet transmission delay. A two-level hierarchy is used for the
Internet-based control systems.At the lower level, a local controller
is implemented to control the plant at a higher frequency. At the
higher level, a remote controller is employed to remotely regulate
the desirable set-point at a lower frequency for the local controller.
A compensator located at the feedback channel is designed to overcome
the time delay occurring in the transmission from the local
site to a remote site. Another compensator in the feedforward
channel is designed to compensate the time-delay occurring in the
control action transmission. The simulation and experimental application
results illustrate that the multirate control scheme with
the time delay compensation offers a promising way to efficiently
reduce the effect of Internet time delay on control performance
