Multiple iPads loose network connection

We are running 12 iPad 3s with a custom application to control LED displays over a 12 lanes of traffic. Each of the iPads have been configured to connect automatically to any of 3 different wireless routers. All of the routers are hardwired into a main switch and are on the same local area network. We are seeing iPads drop off the network with no connection to any router. The only way we have to recover is to go into Settings and reselect a wireless network. We have tried both 5 ghz and 2.4 ghz with no difference in stability or performance. The routers are spread across 12 lanes of traffic - 1 on each side and one in the middle. Each iPad has a static TCP/IP address, as does the router and each of the displays.

Any suggestions on how to stabilize the network connection? This solution must run for months at a time with no issue.