In addition, despite all the technological gains that industrial PCs have made recently, the well of ideas still refills pretty quickly, and so the flow of innovations seems more than likely to continue. For example, Unmanned Ocean Vehicles Inc. (www.UOVehicles.com) near Fredericksburg, Va., is using Opto 22's (www.opto22.com) industrially hardened SNAP programmable automation controller (PAC) and I/O modules to control and coordinate wind, photovoltaic and motion power sources on its 20-foot prototype; store the energy they gather in batteries; use it to power the UOV's on-board propeller; and even navigate. The company reports that its vessels, also known as "satellites of the sea," can travel and operate for up to two years, performing tasks such as bottom mapping, hurricane and storm tracking, and climate monitoring by gathering wind speeds, water temperatures, humidity, barometric pressure and other variables.
"These vehicles can be outfitted to sense, detect and perform the same functions as many manned ships," says Payne Kilbourn, UOV's founder and owner. "The difference is that the UOV is much more cost-effective to operate because it doesn't require fuel, on-board personnel or provisions. Plus, our vehicles can also be deployed and continue to collect scientific data in hurricanes and other conditions where having a manned ship would put lives in jeopardy."
As a result, SNAP PAC serves as a central controller that uses both serial and Ethernet communication to connect to and regulate a multi-vendor team of microcontrollers and marine instrumentation, each with its own area of responsibility, including controlling and rotating the UOV's rigid, winged sail, steering and power management (Figure 2).
Kilbourn adds that he used SNAP PAC's ability to run up to 16 software charts concurrently in one control program, and so the UOV's charts also execute concurrently and all share data. For example, a chart identified as "Captain" includes all the wind-speed monitoring commands, executes the logic needed to determine when to turn the motor on and off, controls at what speed it should run. Meanwhile, the "Navigator" chart uses data from the "Captain" to calculate and decide what course to steer, and it also gauges where the vehicle is with respect to where it's supposed to be.
Meanwhile, Trident Systems' payload interface master module (PIMM) interfaces with the PAC to let UOV transmit Ethernet-based data via high-frequency radio. Other PIMMs connect to onshore computers, and if the UOV is operating near the coast, real-time instrument data from the vehicle is aggregated from the SNAP PAC wirelessly over radio networks. At all times, operators have full access to the control program and can modify any of the UOV's functions, including changing course, repositioning the sail and adjusting speed.
Jim Montague is Control's Executive Editor