UDP network communications for distributed wireless control

The closed-loop control of distributed systems via wireless communication offers many promising applications. Some research has been undertaken in the use of Bluetooth networks for wireless control, resulting in successful stabilization of an unstable plant with a network controller. Wired ethernet networks using the user datagram protocol (UDP) have also been investigated for real-time performance in control, and UDP communications were found to be suitable for this task. In the present study, we make use of wireless UDP communications in peer-to-peer network control loop, which are found to allow for higher sampling rates and better communication range than that achieved with Bluetooth wireless control loops. A simple timing scheme that does not require clock synchronization is used in this control loop as well. Stabilization of an unstable plant has been achieved, and sampling rates up to 250 Hz have been reached with little network data loss. A systematic study of the interplay between range, data loss, sampling rate and performance has also been carried out. Finally, we address the problem of data loss by looking at sampling rate variation, a strategy that improves performance and reliability in the presence of adverse network conditions.