Submersible robot for operating a tool relative to a surface of an underwater structure

Abstract

A submersible robot for operating a tool relative to a surface of an underwater structure has a tool holder movably mounted on a support assembly provided with a driving arrangement for movably holding the tool in operative position relative to the surface. Position and orientation of the support assembly relative to the surface is locked and adjusted by locking and leveling arrangements. A programmable control unit operates the driving, locking and leveling arrangements and the tool and receives measurements from a sensor unit. The control unit has an operation mode wherein a positioning of the robot is determined and controlled as function of an initial position for defining a first work area, and shifted positions of the robot for defining additional work areas, the work areas having overlapping portions with one another for tracking displacements of the robot relative to the surface of the structure using the sensor unit.

The invention claimed is: 
     
       1. A submersible robot for operating a tool relative to a surface of an underwater structure, comprising:
 a support assembly; 
 a tool holder for holding the tool in operative position relative to the surface of the underwater structure, the tool holder being movably mounted on the support assembly so that the tool is movable in a work area relative to the surface of the underwater structure when the tool is mounted on the tool holder; 
 a driving arrangement mounted on the support assembly for moving the tool holder so that the tool is movable within the work area when the tool is mounted on the tool holder; 
 a locking arrangement mounted on the support assembly for locking a position of the support assembly relative to the surface of the underwater structure; 
 a levelling arrangement mounted on the support assembly for adjusting an orientation of the support assembly relative to the surface of the underwater structure when the support assembly is locked by the locking arrangement; 
 a sensor unit directable toward the surface of the underwater structure, for measuring a distance between the robot and the surface of the underwater structure; and 
 a programmable control unit mounted on the support assembly for operating the driving arrangement, the locking arrangement, the levelling arrangement and the tool and receiving measurements from the sensor unit, the programmable control unit having an operation mode wherein a positioning of the robot relative to the surface of the underwater structure is determined and controlled as function of an initial position of the robot for defining a first work area, and shifted positions of the robot for defining additional work areas, the work areas having overlapping portions with one another for tracking displacements of the robot relative to the surface of the underwater structure using the sensor unit. 
 
     
     
       2. The submersible robot according to  claim 1 , wherein the support assembly has opposite ends, at least one of which is provided with a fastener projecting from the support assembly for attachment to a hoisting element. 
     
     
       3. The submersible robot according to  claim 1 , wherein the support assembly comprises an elongated frame, a first mobile member movably mounted on the frame in a longitudinal direction of the frame, and a second mobile member movably mounted on the first mobile member in a transverse direction of the frame, the tool holder being mounted on the second mobile member. 
     
     
       4. The submersible robot according to  claim 3 , wherein the driving arrangement comprises motors and respective rack and pinion assemblies operably coupled to corresponding ones of the first and second mobile members for moving the first mobile member in the longitudinal direction and the second mobile member in the transverse direction. 
     
     
       5. The submersible robot according to  claim 3 , wherein the support assembly is provided with a camera directed to view a displacement of the mobile members. 
     
     
       6. The submersible robot according to  claim 3 , wherein the support assembly has flexible cable guides extending between the programmable control unit and the mobile members. 
     
     
       7. The submersible robot according to  claim 3 , wherein the elongated frame has an opening for passage of the tool holder. 
     
     
       8. The submersible robot according to  claim 1 , wherein the locking arrangement and the levelling arrangement comprise together common complementary sets of adjustable leg members projecting on opposite sides of the support assembly and operable so that the adjustable leg members jut outwardly from the support assembly for pressing against opposite surfaces of the underwater structure to lock the support assembly and adjust a level of the support assembly relative to the surface of the underwater structure, whereby the tool holder has five degrees of freedom in the work area. 
     
     
       9. The submersible robot according to  claim 8 , wherein the set of adjustable leg members on the side of the support assembly opposite to the work area comprises pneumatically actuated pistons mounted on the support assembly, and the set of adjustable leg members on the side of the support assembly facing the work area comprises electrically actuated leg assemblies each having a foot slideably projecting from a housing mounted on the support assembly. 
     
     
       10. The submersible robot according to  claim 9 , wherein each electrically actuated leg assembly further has a motor coupled to a linear actuator connected to the foot. 
     
     
       11. The submersible robot according to  claim 1 , wherein the programmable control unit comprises a watertight enclosure mounted on the support assembly, and an onboard control unit housed in the watertight enclosure, the watertight enclosure being connectable to an umbilical cable through which at least one of power conductors, communication conductors and a gas supply pipe passes. 
     
     
       12. The submersible robot according to  claim 1 , wherein the tool holder comprises a motor connectable to the tool for driving the tool in operation. 
     
     
       13. The submersible robot according to  claim 12 , wherein the tool holder has a magnetic coupling arrangement for connecting the motor to the tool. 
     
     
       14. The submersible robot according to  claim 12 , wherein the tool holder comprises a bearing mechanism for rotatably receiving the tool. 
     
     
       15. The submersible robot according to  claim 12 , wherein the support assembly is provided with a pump and the tool holder has a suction nozzle extending near the tool and coupled to the pump. 
     
     
       16. The submersible robot according to  claim 1 , wherein the sensor unit is mounted on the tool holder, the distance being measured between a predetermined reference point of the robot and a corresponding point on the surface to be machined. 
     
     
       17. The submersible robot according to  claim 16 , wherein the sensor unit comprises a laser sensor. 
     
     
       18. The submersible robot according to  claim 1 , wherein the underwater structure comprises one of a runway, a seal seat, a sill and a lintel of a sluice. 
     
     
       19. The submersible robot according to  claim 1 , wherein the displacements tracked using the sensor unit comprise Cartesian and angular displacements of the robot.