Launch and recovery method for unwired auvs and uuvs

Abstract

A launch and recovery method for unwired AUVs and UUVs (a marine vehicle) is disclosed. A method and system of recovering a marine vehicle floating on a choppy water surface, the method of recovering including determining a zero location coordinates of the marine vehicle floating on the choppy water surface and continuously monitoring a change of location coordinates of the marine vehicle in relation to the determined zero location in real time, moving a gripper to a predetermined distance from the marine vehicle, controlling a position of the gripper at the predetermined distance by continuously changing the position of the gripper according to the monitored change of the location coordinates of the marine vehicle, determining an angle of a central axis of the marine vehicle in the horizontal plane during the change in the location coordinates of the marine vehicle, calculating a moment of grabbing the marine vehicle; recovering the marine vehicle from the choppy water surface at the calculated moment with the gripper.

1 . A method of recovering a marine vehicle floating on a choppy water surface, the method comprising:
 determining a zero location coordinates of the marine vehicle floating on the choppy water surface and continuously monitoring a change of location coordinates of the marine vehicle in relation to the determined zero location in real time,   moving a gripper to a predetermined distance from the marine vehicle,   controlling a position of the gripper at the predetermined distance by continuously changing the position of the gripper according to the monitored change of the location coordinates of the marine vehicle,   determining an angle of a central axis of the marine vehicle in the horizontal plane during the change in the location coordinates of the marine vehicle,   calculating a moment of grabbing the marine vehicle;   recovering the marine vehicle from the choppy water surface at the calculated moment with the gripper.   
     
     
         2 . The method according to  claim 1 , wherein calculating the moment of grabbing comprises calculating a possible grabbing position and comparing the calculated possible grabbing position with suitable positions for grabbing the marine vehicle. 
     
     
         3 . The method according to  claim 2 , wherein calculating the possible grabbing position of the marine vehicle comprises
 receiving images of the marine vehicle,   calculating a distance from the gripper to the marine vehicle,   calculating a position of the marine vehicle's axis in a horizontal plane and the centre of mass based on the visual images and distance measurements.   
     
     
         4 . The method according to  claim 1 , wherein determining the predetermined distance comprises monitoring a change in the location coordinates of the marine vehicle. 
     
     
         5 . The method according to  claim 1 , wherein the predetermined distance is from 10 cm up to 300 cm. 
     
     
         6 . The method according to  claim 1 , wherein the method further comprises moving the gripper from the predetermined distance towards the marine vehicle before the moment of grabbing the marine vehicle. 
     
     
         7 . The method according to  claim 1 , wherein the method further comprises detecting the marine vehicle in a pick-up zone before determining the zero location coordinates of the marine vehicle. 
     
     
         8 . The method according to  claim 1 , wherein the method further comprises active heave compensating of the gripper on the water surface using a motion reference unit (MRU). 
     
     
         9 . The method according to  claim 8 , wherein the method further comprises turning off the active heave compensating, when the gripper is at the predetermined distance from the marine vehicle. 
     
     
         10 . A method of launching a marine vehicle onto a choppy water surface, the method comprising:
 continuously monitoring a change of the choppy water surface in real time,   moving a gripper holding the marine vehicle to a predetermined distance from the choppy water surface,   controlling a position of the gripper at the predetermined distance by continuously changing the position of the gripper according to the change of the choppy water surface,   determining a launching point of time, when a launching wave height is achieved and releasing the marine vehicle at the determined launching point of time from the gripper onto the choppy water surface.   
     
     
         11 . A launch and recovery system for launching and recovering a marine vehicle onto and from a choppy water surface, the launch and recovery system comprising
 a gripper configured to launch and recover the marine vehicle,   one or more sensors connected to the gripper, the one or more sensors being operable to
 determine a zero location coordinates of the marine vehicle floating on the choppy water surface and continuously monitor a change of location coordinates of the marine vehicle in relation to the determined zero location in real time; 
 determine an angle of a central axis of the marine vehicle in the horizontal plane during the change in the location coordinates of the marine vehicle; or 
 continuously monitor a change of the choppy water in real time; 
   a controller operable to
 control a movement of the gripper to a predetermined distance from the marine vehicle or the choppy water surface; 
 control a position of the gripper according to the marine vehicle by continuously changing the position of the gripper based on the change of the location coordinates of the marine vehicle; 
 determine an angle of a central axis of the marine vehicle in the horizontal plane during the change in the location coordinates of the marine vehicle, 
 calculate a moment of grabbing the marine vehicle; or 
 control a position of the gripper at the predetermined distance by continuously changing the position of the gripper according to the change of the choppy water surface, 
 determine a launching point of time, when a launching wave height is achieved. 
   
     
     
         12 . The launch and recovery system according to  claim 11 , wherein the one or more sensors further comprises at least one visual sensor and at least one distance sensor. 
     
     
         13 . The launch and recovery system according to  claim 11 , wherein the marine vehicle further comprises at least two markers detectable by the one or more sensors. 
     
     
         14 . The launch and recovery system according to  claim 11 , wherein the gripper further comprises a motion reference unit (MRU) operable to use active heave compensation (AHC) of the gripper on the water surface. 
     
     
         15 . The launch and recovery system according to  claim 11 , further comprising at least one of lights, high frequency lights or UV lights. 
     
     
         16 . The launch and recovery system according to  claim 11 , further comprising a suspension and retrieval (SAR) apparatus. 
     
     
         17 . The launch and recovery system according to  claim 16 , further comprising a capture device suspended from the suspension and retrieval apparatus for engaging and securing the marine vehicle. 
     
     
         18 . A computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method of  claim 1 .