System and method for accessing ferrous surfaces normally accessible only with special effort

Abstract

A system incorporating a robot to inspect ferrous surfaces. Preferably, the robot is an articulated device having a tractor module for motive power and steering, a power module for electrical power and communications and additional motive power, and a third module for cleaning and inspection. The robot uses sensors and transmits signals to a computer through a tether and receives direction from an operator via the computer and tether. The computer continuously monitors the location of the robot and supports the robot during deployment. In a specific application, the robot travels the interior of a tank on a set of magnetized wheels. Prior to measurement, the tank surface is cleaned of deposits by rotary cutters and rotary brushes on the third module. The robot obtains at least thickness measurements via onboard ultrasonic transducers that contact the cleaned surface. A method for implementing inspection of ferrous surfaces is also described.

1 . A wheeled conveyance employing modules coupled end-to-end along a long axis of said conveyance, said conveyance facilitating inspection of ferrous surfaces indisposed to ready access, comprising:
 at least one central module for powering said conveyance;   at least one front module for steering said conveyance in a current plane of operation,   wherein said front module maintains operable communication with at least said central module; and   at least one rear module for at least abrading said surfaces, said rear module adapted to facilitate maneuvering said conveyance onto a plane of operation different from said current plane of operation,   wherein said rear module maintains operable communication with at least said central module, and   wherein at least one of said modules incorporates at least one sensor to facilitate said inspection.   
     
     
         2 . The conveyance of  claim 1  in which said sensor is selected from the group consisting  25  essentially of: acoustic sensors, ultrasonic transducers, electrical sensors, piezoresistive sensors, attitude sensors, contact sensors, thickness sensors, inclinometers, mutually orthogonal inclinometers, and combinations thereof,
 wherein at least one said sensor is encapsulated in a block of dense, tough and resilient material resistant to wear due to contacting said surfaces while said conveyance is moving.   
     
     
         3 . The conveyance of  claim 1  in which at least a part of at least one said module is sealed and pressurized with an inert gas. 
     
     
         4 . The conveyance of  claim 1  in which said conveyance is portable and configurable to insert into a riser of an underground tank. 
     
     
         5 . The conveyance of  claim 4  in which said conveyance weighs less than about 18 Kg (40 lbs) and is configurable to have a diameter perpendicular to said long axis of less than about 10 cm (4.0 inches) to permit inserting said conveyance into said riser. 
     
     
         6 . The conveyance of  claim 1  in which:
 said front module comprises:
 at least one first wheeled axle assembly having a first at least two polar member wheels of a first diameter, said first polar member wheels comprising a magnetically transmissive material and at least one permanent magnet of a second diameter smaller than said first diameter, each said magnet coaxially mounted between each pair of said first polar member wheels; 
   wherein if more than one said magnet is employed, each said magnet is mounted on said wheeled axle assembly so as to be oriented with polarity opposing that of a nearest mounted one of said magnets;
 at least a first steering mechanism to orient said front module in said current plane; 
   wherein orienting said front module orients said conveyance;
 at least one pivotally mounted first lever arm, 
   wherein said first lever arm operates on said front module to lift and lower said front module; and
 first communicating assemblies in operable communication with at least a portion of said central module to facilitate operation of at least said first wheeled axle assembly, said first lever arm and said steering mechanism; 
   said central module comprises:
 at least one second wheeled axle assembly having a second at least two polar wheels of a first diameter, said second polar member wheels comprising a magnetically transmissive material, and at least one permanent magnet, each said magnet of a second diameter smaller than said first diameter and coaxially mounted between a pair of said second polar member wheels, 
   wherein if more than one said magnet is employed, each said magnet is mounted on said wheeled axle assembly so as to be oriented with polarity opposing that of a nearest mounted one of said magnets;
 at least one motor; 
 at least one first push rod; 
 second communicating assemblies in operable communication at least with said first communicating assemblies to facilitate operation of said first wheeled axle assembly, said first lever arm and said steering mechanism; 
 third communicating assemblies in operable communication with at least said second wheeled axle assembly to facilitate operation thereof; and 
 fourth communicating assemblies in operable communication with said rear module; and 
   said rear module comprises:
 at least one abrading device; 
 at least one maneuvering assembly, 
   wherein said maneuvering assembly permits said rear module to follow said central module onto a surface in a plane of operation different from said current plane of operation of said rear module, and   wherein said rear module may move onto a surface in said different plane only when said conveyance is moving in a forward direction;
 at least one biasing mechanism, 
   wherein said biasing mechanism permits said rear module to maintain firm contact with said surfaces of operation regardless of the orientation of said conveyance; and
 fifth communicating assemblies in operable communication with said fourth communicating assemblies, said fifth communicating assemblies at least facilitating operation of said abrading device and said maneuvering mechanism. 
   
     
     
         7 . The conveyance of  claim 6  in which at least one said motor is a DC reversible servomotor and in which at least one said servomotor incorporates at least one odometric encoder. 
     
     
         8 . The conveyance of  claim 6  in which at least one said polar member wheel incorporates grooves across the width of the outer circumference of said polar member wheel, wherein said grooves enhance traction of said polar member wheel. 
     
     
         9 . The conveyance of  claim 6  in which said abrading device is selected from the group consisting of rotatable brushes, rotatable cutting wheels, scrapers, and combinations thereof. 
     
     
         10 . The conveyance of  claim 9  in which said rotatable brush is cylindrical and axially mounted on said rear module to be approximately parallel to, and approximately the same width as, said second wheeled axle assembly. 
     
     
         11 . The conveyance of  claim 9  in which said scrapers are employed in pairs, mounted adjacent the outer circumference of each of said polar member wheels,
 wherein said pairs of scrapers serve to remove debris that accumulates on said polar member wheels, and   wherein a first said scraper in each said pair is mounted to remove debris when said conveyance is moving in a first direction and a second said scraper in each said pair is mounted to remove debris when said conveyance is moving in a direction opposite to said first direction.   
     
     
         10 . The conveyance of  claim 9  in which said rotatable cutting wheels are cylindrical and axially mounted on said rear module to be approximately parallel to, and approximately the same width as, said second wheeled axle assembly,
 wherein said cutting wheel rotates in the direction of movement of said conveyance and is protected by a unidirectional clutch.   
     
     
         11 . The conveyance of  claim 6  in which said abrading device comprises at least one cylindrical rotatable brush and one cylindrical rotatable cutting wheel,
 wherein each said brush and cutting wheel is axially mounted across the width of said rear module, perpendicular to said long axis and parallel to the plane of operation of said conveyance, and   wherein each said brush and cutting wheel is approximately the same width as said second wheeled axle assembly.   
     
     
         12 . The conveyance of  claim 11  in which said abrading device comprises a first and second said rotatable brush and a first and second said rotatable cutting wheel,
 wherein said first rotatable brush and said first rotatable cutting wheel are rotated upon said conveyance moving in a first direction, said first rotatable brush rotated counter to the rotation direction of said first rotatable cutting wheel, and said second rotatable brush and said second rotatable cutting wheel are rotated upon said conveyance moving in a second direction opposite to said first direction, said second rotatable brush rotated counter to the rotation direction of said second rotatable cutting wheel.   
     
     
         15 . A method for inspecting an interior surface of a ferrous tank of a generally cylindrical configuration with a first end plate opposing a second end plate, said end plates at the extreme ends of the long axis of said tank, comprising:
 deploying into said tank a remotely controllable robotic vehicle comprising three modules, a middle module connected to a front and rear module along a long axis of said robotic vehicle, said robotic vehicle incorporating a connection to a remote power source and controller, at least one sensor, at least one abrading device and magnetic wheeled axle assemblies on said front and rear modules;   controlling said robotic vehicle to navigate along a selected linear path along the long axis of said tank to establish the orientation and position of said robotic vehicle;   generating and recording a graphical representation of said interior surface;   establishing and recording an initial orientation and position of said robotic vehicle;   controlling said robotic vehicle to navigate a pre-established portion of said interior surface;   directing said robotic vehicle to employ said sensor to measure the thickness of said tank at a pre-specified sampling rate while identifying the instantaneous location of said robotic vehicle during said measurement,   wherein said instantaneous location of said robotic vehicle is displayed on said graphical representation;   receiving signals indicative of said thickness measurements;   comparing said measurements with pre-established criteria;   wherein said locations of thickness measurements not meeting said pre-specified criteria are displayed on said graphical representation; and   recording the position of said locations where thickness did not meet said pre-specified criteria.   
     
     
         16 . The method of  claim 15  in which controlling said robotic vehicle to navigate said tank comprises:
 first directing said robotic vehicle to navigate along a line on a cylindrical surface of said tank that is parallel to the long axis of said tank until said robotic vehicle first contacts a surface not parallel to said cylindrical surface;   determining whether said first contacted surface is one of said end plates of said tank;   if said first contacted surface is not a said end plate, directing said robotic vehicle to circumvent said first contacted surface and further like said contacted surfaces that are not an end plate; and   if a said subsequent contacted surface or said first contacted surface is one of said end plates, directing said robotic vehicle to reverse direction by implementing a small angular difference from the prior line of travel of said robotic vehicle;   next directing said robotic vehicle to navigate in said reverse direction along said newly acquired path on said cylindrical surface until said robotic vehicle contacts the opposing said end plate;   repeating said navigation process by reversing direction at said opposing end plates until the entire surface along the long axis of said tank has been navigated;   causing said robotic vehicle to transfer to a first said end plate;   directing said robotic vehicle to navigate along a line through the center of said first end plate until said robotic vehicle first contacts a first surface not parallel to said first end plate;   determining whether said first contacted surface not parallel to said first end plate is said cylindrical surface;   if said first contacted surface is not said cylindrical surface, directing said robotic vehicle to circumvent said first contacted surface not parallel to said first end plate and further like said contacted surfaces that are not said cylindrical surface;   if a said subsequent contacted surface or said first contacted surface not parallel to said first end plate is said cylindrical surface, directing said robotic vehicle to reverse direction by implementing a small angular difference from the prior line of travel of said robotic vehicle;   repeating said navigation process as above until the entire said first end plate surface has been navigated;   causing said robotic vehicle to transfer to said cylindrical surface;   directing said robotic vehicle to navigate said cylindrical surface, now known as to configuration, until said robotic vehicle contacts the second end plate;   causing said robotic vehicle to transfer to said second end plate;   directing said robotic vehicle to navigate along a line through the center of said second end plate until said robotic vehicle first contacts a first surface not parallel to said second end plate;   determining whether said first contacted surface not parallel to said second end plate is said cylindrical surface;   if said first contacted surface is not said cylindrical surface, directing said robotic vehicle to circumvent said first contacted surface not parallel to said second end plate and further like said contacted surfaces that are not said cylindrical surface;   if a said subsequent contacted surface or said first contacted surface not parallel to said second end plate is said cylindrical surface, directing said robotic vehicle to reverse direction by implementing a small angular difference from the prior line of travel of said robotic vehicle;   repeating said navigation process as above until the entire said second end plate surface has been navigated.   
     
     
         17 . The method of  claim 15  dispensing a liquid, said liquid serving as a couplant between said first sensor and said tank. 
     
     
         18 . The method of  claim 15  providing at least one second sensor fixedly mounted to the front of said robotic vehicle,
 wherein said second sensor facilitates determining the location of contacted surfaces in a plane different from that plane of the surface on which said robotic vehicle is traveling.   
     
     
         19 . The method of  claim 18  providing a transition lever arm mounted to said robotic vehicle and operative for lifting said magnetic wheeled axle assembly when said robotic vehicle is transitioning from a first said surface to another surface angular thereto. 
     
     
         20 . The method of  claim 15  providing at least one abrading device mounted on said rear module and positioned so as to contact said surface for cleaning said surface prior to taking measurements thereof with said sensors. 
     
     
         21 . A method of inspecting ferrous surfaces of a structure, said surfaces otherwise inaccessible without employing procedures that are expensive, time consuming, dangerous, or any combination thereof, comprising:
 providing at least one inspection system comprising:
 at least one articulated conveyance for accessing said surfaces without either modifying said structure or expanding access to said structure, each. said conveyance incorporating at least three sections, 
   wherein a front section turns in only a first plane with respect to a middle section and a rear section turns to only a second plane, different from said first plane, with respect to said middle section;
 at least one tether for providing at least power to said conveyance via a means for providing power contained within said tether, 
   wherein said tether may also provide at least one source of fluids;
 at least one control system, at least part of said control system being remote from said conveyance and connected to said conveyance via connection means within said tether, 
   wherein said control system is in operable communication with at least one power source external to said conveyance, and   wherein said power source may be used to power said conveyance via said means for providing power; and
 at least one sensor incorporated in each said conveyance to facilitate semi-autonomous operation thereof; and 
   operating said inspection system for a time period necessary to collect at least one parameter for describing the condition of at least part of said surfaces.