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

• US 20050252296A1
• Filed: 04/05/2005
• Published: 11/17/2005
• Est. Priority Date: 04/20/2000
• Status: Active Grant

• Current Assignee: Charles Marsh, Frank Robb, Vince Hock, Warren Whittaker
• Original Assignee: Charles Marsh, Frank Robb, Vince Hock, Warren Whittaker
• Inventors: Whittaker, Warren, Marsh, Charles, Hock, Vince, Robb, Frank
• Granted Patent: US 7,296,488 B2
• Time in Patent Office: Days
• US Class Current: 73/623
• CPC Class Codes: G01N 2291/02854 Length, thickness
• CPC Class Codes: G01N 2291/2632 flat
• CPC Class Codes: G01N 2291/2636 cylindrical from inside
• CPC Class Codes: G01N 29/041 on the surface of the material, e.g. using Lamb, Rayleigh or shear waves
• CPC Class Codes: G01N 29/225 Supports, positioning or alignment in moving situation
• CPC Class Codes: G01N 29/265 by moving the sensor relative to a stationary material

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 generates 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 inspection, the tank surface is cleaned of deposits by rotary cutters and rotary brushes on the third module. The robot obtains thickness measurements via onboard ultrasonic transducers that contact the cleaned surface. A method for implementing inspection of ferrous surfaces is also described.

Claims

1. A system facilitating access to ferrous surfaces of a structure for purposes such as inspection thereof, said system comprising:

at least one conveyance having a long axis about which sections of said conveyance articulates, said conveyance having at least three said sections operably connected as at least a front section to a middle section and as said middle section to a rear section in line along the long axis of said conveyance,

wherein said conveyance is of a size suitable for deployment upon said ferrous surfaces without either modifying said structure or expanding access to said structure, and

wherein said front section turns in only a first plane with respect to said middle section and said rear section turns in only a second plane with respect to said middle section, and wherein said front section incorporates a first part of a first connection assembly for connection to said middle section, at least one first magnetic wheeled axle assembly comprising polar member wheels and annular permanent magnets and at least one first pivotable lever arm, and

wherein said front section steers said conveyance and transfers to the surface of operation at least part of the power to propel said conveyance, and

wherein said middle section incorporates at least one second magnetic wheeled axle assembly comprising polar member wheels and annular permanent magnets, a second part of said first connection assembly for connection to said front section, a first part of a second connection assembly for connection to said rear section, at least one motor incorporating interoperable connections to at least one device in each of said front, middle and rear sections and at least one first push rod, and

wherein said rear section incorporates a second part of said second connection assembly for connection to said middle section, and at least one abrading device, and

wherein said rear section turns to permit changing the plane of operation of said conveyance only if each of said front, middle and rear sections are at least approximately aligned along the centerline of said long axis of said conveyance, and

wherein said conveyance may move to a surface of operation in a plane different from the plane of the surface of current operation only in a forward direction such that said front section is moved to a new surface of operation prior to said middle and rear sections;

at least one tether in operable communication with said conveyance,

wherein said tether incorporates at least means for distributing power, means for distributing control signals and means for distributing fluids to said conveyance;

at least one control system in operable communication with at least said means for distributing control signals, at least part of which said control system is remote from said conveyance and in operable communication with said conveyance via said means for distributing control signals,

wherein said control system is in operable communication with at least one power source external to said conveyance, and

wherein said power source energizes said motors; and

at least one sensor,

wherein said sensors are incorporated in said conveyance and facilitate at least navigation and inspection functions.

2. The system of claim 1 in which said first plane is parallel to the surface upon which said front section is moving and said second plane is perpendicular to the surface upon which said front section is moving,

wherein said rear section turns only in one direction and only for purposes of permitting said conveyance to change planes of operation.

3. The system of claim 2 in which said conveyance responds to input from at least one first contact switch in operable communication with said first pair of sensors,

wherein said sensors are mounted on a first telescoping mount that is parallel to the front side of said front section, said first telescoping mount compressing uniformly upon contact with a surface that is approximately perpendicular to the surface of operation of said conveyance.

4. The system of claim 2 in which a second pair of said sensors is mounted on a second telescoping mount that is parallel to the back of said rear section, said mount compressing uniformly upon contact with a surface that is approximately perpendicular to the surface of operation of said conveyance, said compression activating at least one second contact switch,

wherein activating said second contact switch alerts said conveyance to the need to alter course.

5. The system of claim 1 in which at least one said motors is a DC reversible servomotor, wherein at least one said servomotors incorporates at least one odometric encoder.

6. The system of claim 1 in which said abrading device is selected from the group consisting of rotatable brushes, rotatable cutting wheels, scrapers, and combinations thereof,

wherein said rotatable brushes and said rotatable cutting wheels are powered by at least one said motor.

7. The system of claim 6 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 said pair is mounted to remove debris when said conveyance is moving in a first direction and a second said scraper in said pair is mounted to remove debris when said conveyance is moving in a direction opposite to said first direction.

8. The system of claim 1 in which said abrading device comprises at least one first rotatable cylindrical brush coaxially mounted on said rear section to be approximately parallel to, and approximately the same width as, said second wheeled axle assembly.

9. The system of claim 8 in which said abrading device further comprises at least one first rotatable cylindrical cutting wheel coaxially mounted on said rear section to be approximately parallel to, and approximately the same width as, said second wheeled axle assembly,

wherein said first cutting wheel rotates in the direction of movement of said conveyance and is protected by a unidirectional clutch.

10. The system of claim 8 in which said abrading device comprises at least one cooperating pair of abrading devices, said cooperating pair comprising a cylindrical rotatable brush and a cylindrical rotatable cutting wheel,

wherein said cooperating pair is coaxially mounted across the width of said rear section, said width perpendicular to said long axis, so as to be parallel to the plane of operation of said conveyance, and

wherein said pair is approximately the same width as said second wheeled axle assembly.

11. The system of claim 10 in which said abrading device comprises a first and second said cooperating pair,

wherein said first brush and said first cutting wheel of said first cooperating pair are rotated upon said conveyance moving in a first direction, said first rotating brush rotating counter to the rotation direction of said first cutting wheel, and

wherein said second rotating brush and said second cutting wheel of said second cooperating pair are rotated upon said conveyance moving in a second direction opposite to said first direction, said second rotating brush rotating in a direction counter to the rotation direction of said second cutting wheel.

12. The system of claim 1 in which each said first and second magnetic wheeled axle assemblies comprises at least three said polar member wheels of a first diameter coaxially mounted parallel one to the other and at least two said annular permanent magnets of a second diameter smaller than said first diameter,

wherein each said magnet is mounted coaxially so as to separate each of said polar member wheels from another of said polar member wheels, and

wherein any said two magnets affixed on either side of a polar member wheel are oriented with opposing polarities.

13. The system of claim 12 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.

14. The system of claim 1 in which said conveyance is portable and configurable to insert into a riser of an underground tank.

15. The system of claim 14 in which said conveyance weighs less than about 18 Kg (40 lbs) and is configurable to have a diameter perpendicular to said long axis thereof of less than about 10 cm (4.0 inches) to permit insertion of said conveyance into said riser.

16. The system of claim 1 in which:

said front section comprises;

at least one first magnetic wheeled axle assembly incorporating three said polar member wheels and two said magnets;

at least a first steering mechanism for orienting said front section in a single plane;

wherein orienting said front section in said single plane also orients said conveyance;

at least one pivotally mounted first lever arm,

wherein said first lever arm operates on said front section to lift said front section from a first surface upon which said first wheeled axle assembly is resting and lower said first wheeled axle assembly to rest upon a surface that may be different from said first surface; and

first communicating assemblies to facilitate operation of said first wheeled axle assembly, said first lever arm and said steering mechanism;

said middle section comprises;

at least one said second wheeled axle assembly having three said polar member wheels and two said magnets;

at least one said motor;

at least one said first push rod;

at least a first part of a maneuvering assembly;

second communicating assemblies in operable communication at least with some said first communicating assemblies;

third communicating assemblies in operable communication with at least said second wheeled axle assembly; and

fourth communicating assemblies in operable communication with at least some parts of said middle and rear sections; and

said rear section comprises;

at least one abrading device;

at least a second part of said maneuvering assembly,

wherein said maneuvering assembly permits said rear section to turn to follow said middle section onto a surface in a plane of operation different from a plane of operation in which said rear section is operating currently;

at least one biasing mechanism,

wherein said biasing mechanism permits said rear section to maintain firm contact with said surface of operation regardless of the orientation of said conveyance; and

fifth communicating assemblies in operable communication with at least some of said fourth communicating assemblies to facilitate at least the operation of said abrading device.

17. The system of claim 1 in which said tether comprises a flexible hollow conduit environmentally sealed at least at the juncture with said conveyance and suitable for containing items selected from the group consisting of:

cables, tubes, tubular nylon core, tubular nylon filler, coaxial cable, extruded jackets, braided jackets, insulated copper wire, wire, hose, pressurized hose, and combinations thereof.

18. The system of claim 1 in which said sensors are selected from the group consisting 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 of said sensors is encapsulated in a block of dense, tough and resilient material suitable for continuously contacting said surface of operation while said conveyance is moving.

19. The system of claim 1 in which said control system comprises:

at least one personal computer,

wherein said computer is interfaced to said conveyance via at least one means of communication carried in said tether, and

wherein said computer facilitates control of said conveyance, positioning of said conveyance, mapping of said surfaces, assessment of said surfaces, and defect identification and location upon said surfaces;

a supply of pressurized inert gas,

wherein said supply is interfaced to said conveyance via at least one means for supplying material carried in said tether;

at least one power source;

wherein said power source supplies at least electrical power to said conveyance via at least an interface to means for supplying power carried in said tether;

at least one transceiver incorporated in at least one said sections of said conveyance,

wherein said transceiver communicates between at least said conveyance and at least said computer; and

at least one retrieval bar affixed to said rear section of said conveyance,

wherein said retrieval bar facilitates recovery of said conveyance from confined locations.

20. The system of claim 1 in which at least a part of at least one said sections of said conveyance is sealed and pressurized with an inert gas.

21. A wheeled conveyance employing modules coupled end-to-end, 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.

22. The conveyance of claim 21 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.

23. The conveyance of claim 22 in which at least one said motors is a DC reversible servomotor and at least one said servomotor incorporates at least one odometric encoder.

24. The conveyance of claim 22 in which said abrading device is selected from the group consisting of rotatable brushes, rotatable cutting wheels, scrapers, and combinations thereof.

25. The conveyance of claim 24 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.

26. The conveyance of claim 22 in which at least one said polar member wheels incorporates grooves across the width of the outer circumference of said polar member wheel, wherein said grooves enhance traction of said polar member wheel.

27. The conveyance of claim 21 in which said conveyance is portable and configurable to insert into a riser of an underground tank.

28. The conveyance of claim 27 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.

29. The conveyance of claim 22 in which said abrading device comprises at least one rotatable cylindrical brush axially mounted on said rear module to be approximately parallel to, and approximately the same width as, said second wheeled axle assembly.

30. The conveyance of claim 22 in which said abrading device comprises at least one rotatable cylindrical cutting wheel 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.

31. The conveyance of claim 22 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.

32. The conveyance of claim 31 in which said abrading device comprises a first and second said rotating brush and a first and second said cutting wheel,

wherein said first rotating brush and said first cutting wheel are rotated upon said conveyance moving in a first direction, said first rotating brush rotated counter to the rotation direction of said first cutting wheel, and said second rotating brush and said second cutting wheel are rotated upon said conveyance moving in a second direction opposite to said first direction, said second rotating brush rotated counter to the rotation direction of said second cutting wheel.

33. The conveyance of claim 21 in which said sensors are selected from the group consisting 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 of said sensors is encapsulated in a block of dense, tough and resilient material suitable for continuously contacting said surfaces while said conveyance is moving.

34. The conveyance of claim 21 in which at least a part of at least one said module is sealed and pressurized with an inert gas.

35. A method for inspecting an interior surface of a ferrous tank, comprising:

deploying into said tank a remotely controllable robotic vehicle employing magnetic wheeled axle assemblies;

controlling said robotic vehicle to navigate along a selected linear path to establish the orientation and position of said robotic vehicle;

providing a graphical representation of said interior surface;

determining the orientation and position of said robotic vehicle;

controlling said robotic vehicle to navigate a pattern that covers at least a major portion of said interior surface;

directing said robotic vehicle to employ at least one first sensor to measure the thickness of said tank at select intervals in said pattern;

receiving signals indicative of said thickness measurements from said robotic vehicle;

identifying at least one instantaneous location of said robotic vehicle,

wherein said location may be displayed on said graphical representation;

comparing said signals with a predetermined thickness standard; and

recording the position of said signals that indicate regions of said surface to be out of standard thickness,

wherein said regions may be displayed on said graphical representation.

36. The method of claim 35 in which controlling said robotic vehicle to navigate said pattern 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 a first end plate of said tank;

if said first contacted surface is not said first end plate, directing said robotic vehicle to circumvent said first contacted surface and further like said contacted surfaces that are not said first end plate; and

if a said subsequent contacted surface or said first contacted surface is said first end plate, 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 again contacts said first end plate;

repeating said navigation process as above until the entire said cylindrical surface has been navigated;

causing said robotic vehicle to transfer to said first 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.

37. The method of claim 35 dispensing a liquid, said liquid serving as a couplant between said first sensor and said tank.

38. The method of claim 35 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.

39. The method of claim 38 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.

40. The method of claim 35 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.

41. 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 of a size suitable 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 suitable to describe the condition of at least part of said surfaces.