Consider the many advantages to operating unmanned ocean vessels (UOVs). They are durable, can navigate long distances and in rough or turbulent seas, and require no personnel. Vehicles designed and built by Payne Kilbourne at Unmanned Ocean Vessels Inc. rely on a combination of wind, photovoltaic, and motion power. Wind is used for propulsion. As the vehicle moves through the water, it turns an on-board propeller. The rotation of the UOV’s propeller generates power that is stored in the batteries and drives the vessel at night or when the wind diminishes.
The SNAP PAC system can operate up to 16 charts concurrently within a single control program.
Kilbourne said his UOVs can travel and operate for as long as two years, map ocean bottoms, track hurricane and storms, and monitor climate through wind speeds, water temperatures, humidity, barometric pressure, and other variables.
He also said that the sensors and instrumentation used to monitor humidity and water temperature use very little power so the solar cells, wind, and batteries are usually more than enough to meet all of the vehicle’s power needs including conveying it wherever it needs to go.
When he designed the 20-ft prototype boat, Kilbourne used Opto 22 SNAP PAC input/output modules and programmable automation controllers. The system can handle the large quantity and variety of inputs and outputs needed for power and navigation, as well as sensing, monitoring, and gathering data. Thus, the SNAP PAC serves as a central controller that uses both serial and Ethernet communication to connect and regulate a multi-vendor team of micro controllers and marine instrumentation, each with its own area of responsibility, including wing (sail) control, steering, and power management.
The UOV has a rigid winged sail that is outfitted with solar cells that must rotate in order to catch the wind. To do this effectively, a serial connection from the controller to a ComNav wind meter accurately measures wind speed and wind direction. The SNAP PAC then uses this data to regulate a Parallax BASIC Stamp microcontroller and stepper motor that adjusts the sail. The PAC also interfaces to an optical sensor to confirm that the sail has moved to the proper position.
Unmanned Ocean’s Vehicles’ prototype rests on the Potomac River. Because the UOV design is scalable (lengths from 12 to 50 ft), new potential applications such as homeland security and oil spill tracking are emerging.
Another microcontroller moves the UOV’s rudder, to ensure that the vehicle maintains proper heading and bearing. Adjustments can be made at any time based on the data input from the onboard Tristar global positioning system (GPS), magnetic compass, or by the UOV operator.
Voltage and current values from the solar cells are measured and a maximum power point tracking (MPPT) device is used to optimizes the sunlight-to-power conversion. Kilbourne said, “We use analog input modules to monitor power generation, power consumption, and battery charge, as well as the performance of the MPPT. This ensures that we achieve peak power voltages and that the proper amount of power is sent to the batteries to optimize solar power production.”
Unmanned Ocean Vehicles Inc.
Filed Under: Energy management + harvesting, Green engineering, Motion control • motor controls, Networks • connectivity • fieldbuses, PLCs + PACs