Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
  • B63B59/00—Hull protection specially adapted for vessels; Cleaning devices specially adapted for vessels
  • B63B59/06—Cleaning devices for hulls
  • B63B59/10—Cleaning devices for hulls using trolleys or the like driven along the surface

Definitions

• the present invention relates to a device for in ⁇ specting underwater parts of fixed or floating objects, for instance ships' hulls.
• the object of the present invention is to provide an inspection device which overcomes at least part of the shortcomings indicated above. Disclosure of the invention
• the unit for dis ⁇ placing the device comprises at least two members ro- tatably mounted on a frame and alternately releasably fixable on the object to allow alternate pivotal movement or turning of the frame on the object, and at least one means which is rotatable by means of a motor in alternating directions and fixed with its motor on the frame and which preferably forms a unit for cleaning the surface to be inspected. 2
• the invention provides an inspection device referred to as inspection robot hereinbelow, which is capable of moving step by step on the object by means of members, for instance suction discs, electromagnets or the like, alternately fixed on the object and whose frame for each step is pivoted a certain distance in one direction as a result of the reaction force and the torque from one or more motor-driven rotary means, such as wheels, propellers or, preferably, cleaning units, such as brushes or scrapers, acting against the object and at the same time exposing the surface to be inspected, to an inspection unit, such as a TV camera.
• members for instance suction discs, electromagnets or the like
• members for instance suction discs, electromagnets or the like
• the invention provides an inspection device referred to as inspection robot hereinbelow, which is capable of moving step by step on the object by means of members, for instance suction discs, electromagnets or the like, alternately fixed on the object and whose frame for each step is pivoted a certain distance in one direction as
• the pivotal movement of the robot is obtained by the brush rotating in the opposite direction and having its centre of rotation spaced the same distance from the centres of rotation of the two suction discs, which latter centres may also suitably be spaced from each other by said distance.
• the brush is capable of cleaning a surface which is at least equally wide as required by a suction disc for ensuring a safe en ⁇ gagement against the object, one suction disc will always advance along a cleaned path irrespective of the ampli ⁇ tude of the angle of pivotment.
• the in ⁇ spection robot for each step may pivot for instance through 60°, whereby the displacement in the main di ⁇ rection becomes equal to the selected distance between the centres of rotation of the two suction discs and between these centres and the centre of rotation of the rotary brush.
• the energy being e.g. electric or hydraulic and 3 controlled by a control unit, for instance a microcom ⁇ puter, or by an operator, may be supplied to the motor of the brush by a power supply cable by means of which e.g. information from a robot-navigating TV camera, an inspecting TV camera, optionally ultrasonic plate thickness measuring means, a potential metering reference electrode, etc, may also be transmitted to a suitable control and observation site above the water surface.
• a control unit for instance a microcom ⁇ puter, or by an operator
• this information may be obtained from an instrument measuring the angle between the vertical and a reference line on the robot, this also giving information on the direction of travel of the robot. Instruments of this type are previously known.
• On horizontal surfaces e.g. the flat bottom of a vessel, one must however rely on "dead reckoning" to a greater extent, until the navigating or inspecting TV camera has recorded e.g. a weld joint which may be used as reference direction.
• each suction disc may for example be provided around its periphery with a number of equidistantly distributed detectable bodies, for instance magnets or pieces of soft iron, which upon passage of a sensor emit a pulse. The angle between the different pulse passages is de ⁇ termined by the number of detectable bodies.
• control unit For a change of course of the robot, the control unit (microcomputer) is supplied with an instruction (e.g. an instruction programmed in advance) to demand, for a change of the direction of the course, a larger number of pulses or, alternatively, a smaller amount of pulses in the opposite direction of rotation before initiating switching of suction discs and change of the direction of rotation of the brush.
• an instruction e.g. an instruction programmed in advance
• the arrangement may be such that the operator, on a control panel in the control unit, first pushes a button indicating the direction of change of the course and thereafter digitally the desired change of course.
• Fig. 1 schematically illustrates the inspection robot from above
• Fig. 2 schematically illustrates the robot from the side, turned upside down with respect to Fig. 1.
• Fig. 3 is an example of a sequence of movement which the robot can perform.
• the inspection robot generally designated 1 is connected by means of a power supply cable 2 to a control unit (not shown) disposed above the water surface and accessible to an operator, e.g. on the vessel of which the parts located under the water surface should be inspected.
• the control unit may be an e.g. programmable microcomputer.
• the inspection robot 1 is carried on a flat frame 3 in which two suction cups or discs 4 are articulated.
• the centres of rotation of the discs are designated V and H-, respectively.
• the motor for a motor-driven circular brush 5 rotatable in both directions is fixedly mounted on the frame 3 such that the brush will be located on the same side of the frame as the suction discs.
• the centre of rotation of the brush is designated B.
• V, H and B are located in the corners of an equilateral triangle or adjacent thereto.
• a water pump 6 which by hoses 7, is adapted alternatingly to suck water from the left suction disc 4 fixed to the object, and to eject the water in the right disc being released, and vice versa.
• suction discs are known per se.
• the motor of the pump 6, like the motor 8 for the rotary brush 5, may be driven pneumatically, hydraulical- ly or electrically. Hydraulics being preferred for various reasons, the continued description will be concerned with that alternative.
• the direction of the hydraulic flow through the two motors 6, 8 is determined by an electrically operated directional valve 9 which, by an electric lead in the power supply cable 2, is operably connected to the control unit.
• the bearings of the suction discs 4 are hollow for said pump-generated flows of water and spherical to enable the discs 4 to adjust themselves against any inclined surface, for instance when climbing on a pipe.
• the cleaning brush 5 By its rotational movement, the cleaning brush 5 produces a torque on and, by simultaneously engaging the ship's hull, a reaction force against the frame 3, resulting in a pivotal movement of the robot, about the suction disc 4 presently sucked to the object, in a direction opposite to the direction of rotation of the brush.
• the brush 5 When the right-hand suction disc 4 is fixed to the object, the brush 5 is rotated to the left, whereby the entire robot 1 will pivot to the right with the right-hand suction disc 4 as centre of rotation. If the pivotal movement is 60°, the left-hand suction disc 4 will come to the position which the brush 5 occupied when starting to walk to the right.
• control unit After sensing the angular change corresponding to one step, the control unit switches the directional valve 9 and the direction of rotation of the brush 5, such that the same pivotal movement of the robot is performed in the opposite direction.
• the effective or resultant direction of travel will then of course lie between the two turning positions. If the diameter of the brush 5 exceeds the diameter of the suction discs, the robot can pivot to an unlimited extent without any suction disc entering into a non- brushed area.
• the control unit is so designed as to permit ob ⁇ taining a change of course by requesting a larger pivotal movement of the robot in the desired direction before ordering the robot to turn, or a pivotal movement through a smaller angle in the opposite direction. in the case where the reaction moment from the rotary brush 5 is not capable of sufficiently rapidly pivoting the robot forwards in a step, it is possible to incline the brush 5 slightly, so that its edge remote from the suction discs 4 is pressing slightly harder against the object.
• the robot 1 is navigated by means of a TV ca- mera 12 which is oriented in the direction of travel, and performs the inspection by means of a TV camera 13 which is disposed just astern of the suction discs 4.
• the inspection camera 13 may be replaced by a video equipment, a potentiometer or an ultrasonic meter, as described above, according to the purpose of the in ⁇ spection.
• the navigation camera 12 and the inspection camera 13 are mounted on either end of a beam 14 which inter- mediate its ends is fixed at the upper end of a post
• the post 15 rotatably mounted on the frame 3.
• the post 15 extends at right angles to the surface to be inspected and is suitably disposed far astern where the movements trans ⁇ versally of the direction of travel are not as rapid.
• the post 15 with the associated beam 14 and the cameras 12, 13 is balanced hydrostatically and hydrodynamically and should theoretically be able to maintain its direction close to the direction of travel.
• the navigation camera 12 is of course directed forwards in the direction of the beam 14, and the in ⁇ spection camera 13 at the rear end of the beam is directed straight inwards towards the surface, for instance the shell plating of a vessel.
• fixed dampers can be arranged or allowed to pivot inwards such that every time the robot 1 commences a new step (change of direction) they can remind the camera-supporting beam 14 of the correct orientation.
• the pivotal movements of the inspection robot 1, water currents etc. should affect as little as possible the orientation of the camera-supporting beam 14 in the direction of travel.
• the above-mentioned hydrodynamic stabilization and dampening is however difficult to ensure with currents of varying angles of incidence.
• the beam 14 may be maintained in the direction of travel mechanically or electrically.
• the movements of the suction discs 4 and the beam 14 may be synchronized, for instance by means of toothed wheels and chains, links etc.
• the microcomputer is ordered to cause the robot 1 to move a certain number .of steps in a certain direction, . . . whereupon a resting position can be programmed, in which the brush 5 should be stopped in order not to wear out the paint covering the hull, or normally a change of course.
• the memory of the microcomputer may receive a sequence of orders simultaneously. Another memory may then be used for storing and subsequently documenting all operational steps.
• Fig. 3 schematically illustrates from below the pattern of movement of the brush 5 and of the suction discs 4, the centres of the successive turning positions of the brush 5 being designated Bl B10.
• the centre of rotation of the left suction disc 4 is designated
• the inspection robot 1 e.g. in phase 5, will pivot about the point VS_5 (coinciding with the point, VS4, to which the left suction disc 4 is moved in phase 4, and the point, B3, where the brush 5 has switched its direction of rotation and movement in phase 3) , and the centres of rotation of the robot 1 are located in the three positions "5" immediately before a change of course and change of the centres of pivotment of the robot.
• the robot pivots about HS6, VS assuming the turning position, B5, VS6, VS which the brush has just left, and the brush moves to position B6.
• phase 7 VS is locked (in VS7) , and HS is released and accompanies the robot to HS7 while the brush 5 moves up to B7.
• the hatched portions in Fig. 3 define the surface cleaned by the brush 5.
• the inspeciton robot 1 moves from one section of the surface to another, as appears from Fig. 3, on a straight course, always with pivotal movements of 60 .
• the length of each step in the direction of travel then becomes equal to the side of the equilateral triangle defined by the centre of rotation B of the brush and the centres of rotation V and H of the suction discs.
• the required "road width” freely available and relatively free from obstacles substantially corresponds to the double brush diameter, slightly more than 90% of the "roadway” being cleaned. Only in the case of a very close turn, a relatively small isolated spot may escape brushing, which is however of no practical consequence.
• suction discs 4 there may be provided more than two suction discs 4 and more than one brush 5.
• These members may be combined in dif ⁇ ferent groups and/or units together yielding the desired function.
• the driving rotary means consists of a cleaning unit
• the brush 5 may be replaced by a series of sea-acorn scapers or consist of a combination of brush and scraper.
• Such cleaning units may, as mentioned above, be replaced by propellers, wheels etc. for pivoting the frame.
• the pivotal movement of the frame about the members 4 may also be achieved by turning directly at the members, for instance by means of gear rings mounted on the members and meshing with toothed wheels rotatable by means of a motor.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• Ocean & Marine Engineering (AREA)
• Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
• Manipulator (AREA)

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• 1984
  • 1984-07-23 SE SE8403826A patent/SE8403826L/sv not_active Application Discontinuation
• 1985
  • 1985-07-23 EP EP19850903725 patent/EP0188565A1/en not_active Withdrawn
  • 1985-07-23 WO PCT/SE1985/000293 patent/WO1986000860A1/en unknown

Non-Patent Citations (1)

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