Hybrid propeller/undulating fin propulsion for aquatic vehicles

Abstract

An apparatus and method for an unmanned underwater vehicle that utilizes at least one flexible robotic fin to provide a highly maneuverable vessel with station-keeping performance in tight spaces, close to ocean structures or missions where a low-speed or station-keeping vehicle is required. A propeller is also provided for providing the main propulsion during high-speed transition with assistance provided by the flexible robotic fin. The vehicle includes sonar and camera equipment as well as a plurality of other sensors for achieving navigation and communication functions while surveying the underwater marine environment. A system controller and motor controller are synchronized to provide deflection commands to ray elements in the flexible robotic fin to achieve particular maneuvers such as pitch, yaw, and roll in confined spaces. The commands are traveling waves that undulate the fin precisely and for station-keeping the commands are opposing wave commands that fix the vehicle at one position.

What is claimed is: 
     
         1 . An unmanned underwater vehicle for maneuvering in tight spaces, close to ocean structures or missions where a low-speed or station keeping function is necessary, said vehicle comprising:
 a hydrodynamically-shaped hull having at least one robotic fin positioned on an external surface of said hull, said at least one robotic fin being flexible such that portions of the fin can undulate to cause said hull to pitch, yaw or roll in a confined underwater space;   a sonar device for detecting underwater objects proximate said vehicle; and   a controller, coupled to said sonar device, that commands said at least one robotic fin using at least one traveling sinusoidal wave to undulate said at least one robotic fin and maneuver in the confined underwater space.   
     
     
         2 . The unmanned underwater vehicle of  claim 1  further comprising a pressure sensor coupled to said controller for detecting the pressure external of said vehicle representative of a water depth of said vehicle. 
     
     
         3 . The unmanned underwater vehicle of  claim 2  wherein said controller commands said at least one robotic fin using a second traveling sinusoidal wave that is oppositely-directed to said at least one traveling sinusoidal wave to effect station keeping of said vehicle. 
     
     
         4 . The unmanned underwater vehicle of  claim 1  further comprising a camera that is coupled to said controller. 
     
     
         5 . The unmanned underwater vehicle of  claim 1  further comprising a propeller located at a stern of said hull and coupled to said controller for activating said propeller to propel said vehicle underwater. 
     
     
         6 . The unmanned underwater vehicle of  claim 1  further comprising a radio coupled to said controller for effecting remote communication from and to said vehicle. 
     
     
         7 . The unmanned underwater vehicle of  claim 1  wherein said at least one robotic fin comprises a plurality of rays that can be deflected by said at least one traveling sinusoidal wave. 
     
     
         8 . The unmanned underwater vehicle of  claim 7  wherein each of the plurality of rays is controlled by a separate actuator, wherein each actuator is controlled by the controller. 
     
     
         9 . The unmanned underwater vehicle of  claim 1  further comprising a global positioning system coupled to said controller for effecting detection of the location of the unmanned underwater vehicle 
     
     
         10 . A method for maneuvering an unmanned underwater vehicle in tight spaces, close to ocean structures, or missions where a low-speed or station keeping function is necessary, said method comprising:
 providing a hydrodynamically-shaped hull with at least one robotic fin positioned on an external surface of said hull, said at least one robotic fin being flexible such that portions of the fin can undulate to cause said hull to pitch, yaw, or roll in a confined underwater space;   providing said hull with a sonar device for detecting underwater objects proximate to said vehicle;   coupling said sonar device to a controller within said hull for providing said controller with data regarding objects in the vicinity of said vehicle; and   commanding said at least one robotic fin using at least one traveling sinusoidal wave, by said controller, to undulate said at least one robotic fin and maneuver said vehicle in the confined underwater space.   
     
     
         11 . The method of  claim 10  wherein said controller commands a plurality of actuators, each actuator coupled to a ray on the at least one robotic fin. 
     
     
         12 . The method of  claim 11  wherein said controller commands each actuator to move in unison with the rest of the plurality of actuators to move the at least one robotic fin as a single piece. 
     
     
         13 . The method of  claim 11  wherein said controller commands each actuator to move independently from the rest of the plurality of actuators to move the at least one robotic fin in an undulating pattern. 
     
     
         14 . The method of  claim 10  wherein the at least one robotic fin provides the only source of thrust during low-speed operation or station-keeping. 
     
     
         15 . The method of  claim 10  further comprising providing the hydrodynamically-shaped hull with a propeller coupled to the rear of the hull. 
     
     
         16 . The method of  claim 15  further comprising thrusting the unmanned underwater vehicle at high speeds by activating the propeller and maneuvering the unmanned underwater vehicle via commanding the at least one robotic fin. 
     
     
         17 . The method of  claim 10  further comprising providing said hull with a camera for detecting underwater objects proximate to said vehicle and coupling said camera to the controller within said hull for providing said controller with visual data regarding objects in the vicinity of said vehicle. 
     
     
         18 . The method of  claim 10  further comprising providing said hull with a global positioning system for detecting the position of the vehicle and coupling said global positioning system to the controller within said hull for providing said controller with data regarding the location of said vehicle. 
     
     
         19 . The method of  claim 10  further comprising provided said hull with acoustic sensors for recording sounds surrounding the vehicle and coupling said acoustic sensors to the controller within said hull for providing said controller with acoustic data. 
     
     
         20 . The method of  claim 10  further comprising transmitting and receiving wireless communications between the vehicle and another source selected from the group including another unmanned underwater vehicle, an aquatic structure, a land-based vehicle, air-based vehicle, and an external operator.